Larger diameter wheels. Upgrading wheels and tires. Resizing wheels and tires. Modernizing wheels and tires. Campy clones, etc.

D-

Welcome aboard. Sympathy for the loss of your father.

Tire Diameter and Front to Rear Δ

Like any car the Pantera's front and rear wheel wells will only look “GOOD” with front and rear tires that are within a small range of diameters. One very unusual aspect of the Pantera is that the front fender openings were deigned for tires approximately 2 inches smaller in diameter than the Pantera's rear tires.

A front tire 25 inches in diameter fills the front fender opening quite fully, whereas a front tire smaller than 24 inches in diameter begins to look proportionally too small for the fender opening. Therefore front tire diameter should remain within the range of 24” to 25”.

A rear tire 27 inches in diameter fills the rear fender opening quite fully, whereas a rear tire smaller than 26 inches in diameter begins to look proportionally too small for the rear fender opening. Therefore rear tire diameter should remain within the range of 26” to 27”.

In terms of appearance the tire set should use front and rear tires with diameters that fill the front and rear fender openings the same amount, i.e. the difference in the diameter of the front and rear tires  (the "Δ") should be about 2 inches. Setting-up the chassis around a tire set like this will also result in the chassis geometry being set-up as it was designed.

This difference in tire diameter (the Δ) is the most basic aspect to get right in terms of appearance AND chassis set-up, which is why I've mentioned it first thing, right up front. You'd be surprised how often this has been gotten wrong.

Ride Height

Using tires on the small end of acceptable diameters (24" front, 26" rear) will only lower the car 1/2 inch compared to tires that are on the large end of acceptable diameters (25" front and 27" rear). Small diameter tires don't lower the car tremendously. A lowered ride height is more a function of chassis set-up.

North American Panteras were equipped with spacers between the springs and shocks to raise their ride height about 1". The spacers were omitted from the European models. In other words, the European "standard body" Panteras sit 1" lower to the ground than their North American cousins. If a reader's US Pantera still has those spacers installed, then the first step towards achieving a lower "stance" is to remove the spacers. Lowering the Pantera improves appearance AND handling.

However, rather than rely on the ride height built into the factory shocks and springs, ride height and stance can be "dialed-in" much better utilizing modern gas shocks that feature the ability to adjust spring pre-load. Shocks with adjustable spring pre-load make it possible to fine tune the front and rear ride height individually. I would add my voice to those of David and Devin who both already hinted at this:

quote:

Originally posted by David_Nunn:

... with a good spring/shock package, the "stance" of the car no longer depends upon tire diameters.

quote:

Originally posted by Garvino:

... came to the conclusion that I wanted the ability to adjust the ride height of my car to my specific liking. I ended up buying a new set of Koni’s with Hyperco springs and am glad that I did.

The compliance of modern gas shocks complements the shorter/stiffer sidewalls of lower profile tires more so than the OEM shocks. Therefore everyone should consider installation of modern gas shocks a pre-requisite for the installation low-profile tires, regardless of wether or not they plan to change their Pantera's ride height. 

Setting-Up a Pantera Chassis

Whereas many automobiles are “lowered” by their owners to improve handling, the Pantera was originally designed to be about as “low as you can go” right off the showroom floor (before Ford raised the Pantera's ride height by 1 inch). If you set-up your Pantera to ride as it was originally intended by its famous designer (Gian Paolo Dallara), I don't think you'll be disappointed.

In preparation the fuel tank should be half full with fuel, the driver & passenger should be sitting in the seats, and the tires should be filled to the appropriate air pressure.

If the shocks have pre-load adjustment (its optional with the steel body Koni shocks) the chassis needs to be leveled; i.e. the frame rails that run below the doors should be equal distant to the ground front to back, and side to side. The minimum ride height sets the rear lower control arms level with the ground. To achieve that ride height adjust the rear springs first, then level the chassis by adjusting the front springs.

At this point the car is about as low as its going to get. My Pantera is set-up this way, and a racing style floor jack barely fits under the jacking points. The car bottoms out on large high speed bumps and dips, and the middle of the car scrapes certain driveways and speed bumps. I personally wouldn't want the ride height of my Pantera to be any lower than this. My Pantera has spring rates of 450 lbs front and 550 lbs rear. If the springs were softer it would bottom out more often.

If your Pantera is equipped with a front/rear tire combination in which the front tires are 24 to 25 inches diameter, the rear tires are 26 to 27 inches diameter, and the rear tires are about 2 inches greater in diameter than the front tires, then after adjusting the front and rear ride height in this manner the tires should be centered in the fender openings, and the gaps between the tires and fender openings should be fairly equal front to rear. This provides best appearance and best chassis set-up.

Upgrading to Modern Wheels and Tires

quote:

Originally posted by Clockwork:

... I've basically given up on 15" tires and have decided to move on to Campi Clones …

If you're going to go out and just purchase a set of Campy clone wheels with 17x8 front dimensions and 17x11 or 18x12 rear dimensions … the tire choices are:

(1) Front: 245/35ZR17 (23.75 diam.) Rear: 285/40ZR17 (25.98 diam.) 2.23 Δ
(2) Front: 235/40ZR17 (24.40 diam.) Rear: 335/35ZR17 (26.23 diam.) 1.83 Δ
(3) Front: 245/35ZR17 (23.75 diam.) Rear: 335/30ZR18 (25.91 diam.) 2.16 Δ

These are what I call "small diameter" tire sets, on par with the Pirelli P7 that were installed on the narrow bodies beginning 1977 (225/50VR15 and 285/50VR15). Some vendors choose to use 225/45R17 front tires which are 24.97 inches diameter. That is not a "small diameter" front tire, and tires in that size are not good front tires to complement the usual rear tires due to the resulting difference in front to rear diameters (i.e. the Δ).

Tire availability (according to The Tire Rack, 2019):
235/40ZR17: (6) Dunlop, Falken, Sumitomo, Toyo (Proxes R1R), Yokohama (x2)
245/35ZR17: (1) Toyo (Proxes R1R)
285/40ZR17: (2) Continental, Pirelli P Zero
335/35ZR17: (2) Michelin Pilot Sport, Pirelli P Zero
335/30ZR18: (4) BF Goodrich G-Force (x2), Pirelli P Zero (x2)

Unfortunately according to The Tire Rack  (2019) there are no "sets" available using the same make and model of tire for the front and rear.  This is a dismal situation. Installing the ultra-wide 17 inch  rear tire requires a compromise in wheel width and offset, but the 18 inch rear tire does not; therefore the 18 inch rear tire may be a better choice.  Availability of both of the 17 inch rear tires seems to be off and on as well.

However ...  

You can purchase wheels sized for tire sets that will improve the tire availability situation. Would you care to take a brief excursion down the rabbit hole with me?

The 335/35ZR17 rear tire has been around since 1990, the 335/30ZR18 tire has been around since 1995. The tire sets listed above AREN"T REALLY MODERN.

Appearance is always high on everyone's criteria when it comes to upgrading tires and/or wheels. But another possible criteria for selecting tires or wheels is the availability of front/rear tire sets. Acquiring tires in sizes which aren't supported by the tire industry can be frustrating and expensive. Life is frustrating enough without spending a lot of money on a wheel set which adds to life's frustration. Spending a sizeable amount of money on something that adds to life's frustration is tantamount to shooting yourself in the foot.

De Tomaso owners considering the purchase of aftermarket wheels in the year 2012 2019 are doing so for one to three reasons:

• Because they are frustrated with the availability of 15", 16", or 17" tires. They need wheels designed for tire sets in sizes that are available from several tire manufacturers now and shall continue to be available into the future.
• Because they want to modernize the appearance of their Pantera.
• Because they want to improve the performance of their Pantera, which includes equipping it with the best performing modern tires they can afford.

If you're going to spend a substantial amount of money on a new set of wheels, it makes sense to purchase the wheels for a tire set that shall be available for the next 15 to 20 years, and for which more than one make and model of tire is available. I don't need to tell you that the auto industry is currently installing 18", 19", and 20" wheels on new high performance production automobiles. Aspect ratios are 40 on the tall side, 35 and 30 predominantly, and even as low as 25 on the short side. A 4 inch sidewall is a tall one in today's world; even SUVs have 4" sidewalls. In some cases sidewall height has dropped a bit below 3 inches.

Based upon the availability of "tire sets" a new set of wheels TODAY (2012 2019) should incorporate 17" or 18" front tires and 18" or 19" rear tires. The choices in 18" rear tires for the Pantera are not bountiful. But they are better than the choices in 15", 16" and 17" tires. 

As an example, the German engineered 2017 Audi R8 is propelled by a naturally aspirated 5.2 liter V10 engine rated at 540 BHP and 398 ft./lbs. torque. Its curb weight is 3649 pounds; that weight is distributed 42% on the front tires and 58% on the rear tires. It accelerates from a standstill to 60 MPH in 3.5 seconds. It circles the skid pad at 1.00 G; and it stops from 70 MPH in 153 feet. It is equipped with 245/35R19 front tires and 295/35R19 rear tires as standard equipment. I am confident that a tire complement similar to this is well suited for most Panteras.

Future Tire Availability:

These two internet sites help in judging the availability of tires, they both allow you to perform a search based on tire size. One very beneficial feature offered by both web sites, they allow you to search by size for "sets" of tires wherein the front tires and rear tires are a different size.

Tire Rack.com/

On Line Tires.com/

The web site linked below lists the OEM applications of the various tire sizes, and the years. Obviously more applications, and/or more recent usage will indicate good prospects for future availability.

Size My Tires

Possible Tire Sets

Once you've selected a set of tires you have to acquire a set of wheels to mount them on.

Wheel Width

Unlike the average car in which all 4 tires are the same size, and all 4 wheels are identical (same width and offset) the Pantera uses front and rear tires differing in width and diameter by a significant amount, and requires wheels of different widths and offsets for front and rear.

In the past, when tire sidewalls were "taller", the width of sports car wheels was usually 50% of the tire’s rim width range, or at least as wide as the tire's tread. If a wheel with that width was not available, a wider wheel would be chosen. This helped stiffen the sidewall for better handling. However, with modern "performance" tires having such "short" sidewall height, the "need" to do this is a moot point ... the sidewalls are plenty stiff already.

With the "short" sidewalls of modern tires wheel width should be a bit narrower than tread-width. This squares-up the sidewall which accomplishes 3 important things:
(1) It protects the wheel from damage in pot-holes.
(2) It helps in protecting the wheels from curb rash.
(3) It "squares-up" the tire sidewalls for best appearance.

Since wheel width affects the tires appearance, the front/rear wheel widths should "square-up" the sidewalls of the front/rear tires a similar amount for balanced front/rear appearance in this regard.

Wheel Offset

The trend in aftermarket wheels for the Pantera has been to set the front tires too far inwardly (excess offset) and the rear tires too far outwardly (insufficient offset). The result is an imbalance in the appearance of the car. I advocate setting front and rear offset to set the edges of the tires' outer sidewalls inwardly from the front and rear fender edges an equal amount for balanced front/rear appearance.

I recommend recessing both front and rear tires inwardly by 20mm. UNLESS of course the car shall have ultra-wide tires in the rear, in that case set the rear wheels flush with the fenders edge.

Pantera Tire Rubbing Issues

• 245mm cross-section front tires and 335mm cross-section rear tires are the limits in tire width in terms of avoiding rubbing issues in a narrow body Pantera.

• Offset at the front or rear making the outer sidewall of the tires flush with the fenders’ edges MAY result in rubbing at the fender opening flanges, and MAY make it necessary to “roll” them. Rubbing is also impacted by tire diameter, ride height, and camber settings ... tires larger in diameter are more likely to rub than tires smaller in diameter.

• Front tires with 245mm cross-section mounted on wheels with 22mm offset MAY rub the wiper motor’s protective housing in the right wheel house at full lock, and MAY rub the inner wheel house at full-lock as well; in general 22mm front wheel offset has worked well in avoiding any rubbing issues. If rubbing occurs it shall be minor and only occur in low speed parking maneuvers; it shall not be a significant problem.

• On rare occasions front tires greater than 25.0 inches diameter have rubbed the lower front corner of the fender openings, this is because the front tires are not centered within the fender openings, they are positioned forward of center. This situation is the result of Ford’s decision in 1971 to reduce caster in order to promote “understeer”. This can be reversed by moving the upper ball joints 5/8 inch (15mm) rearward via modification of the upper front control arms. This revision centers the front tires within the fender openings thus improving appearance and eliminating rubbing in the lower front corners of the fender openings (if rubbing is a problem). It also restores the Pantera’s originally intended 6° of caster which improves directional stability and reduces understeer. Debbie and I recommend this "reversal of Ford tampering" for every Pantera.

• Rear tires greater than 26.5 inches diameter and wider than 285mm MAY rub the OEM Ansa mufflers, and MAY require modification of the mufflers to create clearance.

• New shock absorbers have more travel built into them than the OEM shocks. Rear tires often rub the upper portion of the wheel houses over large bumps due to the additional travel built into the new shocks. This rubbing is resolved as it was with the OEM shocks, by limiting shock travel ... not by altering offset. Shock travel is easily limited via installation of a second set of "stop rubbers" on the shock absorber shafts.

•  Rear wheels that are 15", 16", or 17" diameter are limited to 6-1/2" "calculated" back-space (or an actually measured back-space of 6-1/4"). A wheel in those diameters shall rub the lower rear control arms at 6-3/8" actual back-space. This normally limits rear wheels in those diameters to 11" width and 12mm offset. This impacts wheels designed for 335/35R17 tires. Wheels larger than 17" diameter have enough clearance to avoid rubbing the lower rear control arms; this limitation doesn't apply to them.

Wheel Specs

Where To Acquire Pantera Wheels In Diameters Appropriate For Modern Tires

The Campy clone wheels sold via a few Pantera vendors are easy to acquire, but they have NEVER represented all the wheel options available to Pantera owners. Here are three alternative wheel choices which are available to everyone …

(1)  Custom manufactured Campy clone wheels, which can be ordered in larger diameters, are available from American Republic Wheels (Boyd Coddington USA web address). The "Campi" wheels are among their "Elite Series" of wheels. The centers of these wheels have 3 dimensional "depth" like the OEM Campy wheels, more so than other Campy clone wheels. For instance the frames around the "windows" tilt outwards at an angle whereas other Campy clones are flat as a pancake. To machine the wheel at multi-angles like that requires more time on the CNC machine, and makes the wheel more expensive. These wheels are gorgeous, and a good option for Pantera owners.

Boyd Coddington once manufactured the wheels for Pantera East, the Pantera East wheels had several features which made them closer in appearance and function to the OEM Campy wheels than other Campy clones on the market.

• 62mm hub bore diameter
• wheel center designed for the OEM logo disc held-in by a circlip, instead of a "pop-in" cap
• reproduction of the intermediate "step" built into the original wheel
• old-style (traditional) wheel "lip" design

Boyd Coddington is under new ownership, it has been owned by American Republic Wheels since 2010. Please be forewarned their standard "Campi wheel" spec is a rather generic style wheel spec. It lacks the features listed above that were found in the wheels formerly produced for Pantera East. It is not marketed as a "Pantera wheel", it is intended for owners of classic American hot rods and muscle cars who like the Campi look. If you want a wheel that is more Pantera-specific or similar to the Pantera East wheel, be sure to start the exchange by explaining the wheels are for a Pantera AND you want wheels machined and assembled to the former Pantera East specification, except in terms of diameter, width, and offset. Be specific with what you're looking for. They have a CNC program for the Pantera East wheel, owners have been able to have wheels produced to that spec.

Please be forewarned doing business with American Republic Wheels has been an exercise in frustration and disappointment for some folks. If you do business with them, please share with us your experiences.

(2) Roin Technology of Italy (represented in the US by one of our forum supporters, Mr. Fiat) manufactures authentic looking Campy replica wheels in 15" and 17" diameters, and they are in the process of making them available in 18" diameter too. The wheels are CNC machined from solid blocks of billet aluminum. Being manufactured from billet aluminum instead of cast magnesium is a huge benefit. Monoblock wheels like this are the cream of the crop … the best wheels you can buy.

Two possible tire sets using Roin's new 18" wheels would be:

Front: 245/40ZR17 mounted on 17x8.5 (16mm offset)
Rear: 275/40ZR18 mounted on 18x9.5 (8mm offset)
There are currently 18 tire sets listed at the Tire Rack for tires in these sizes.

OR

For the owners who want an "ultra-wide" rear tire:
Front: 245/35ZR17 mounted on 17x8.5 (16mm offset)
Rear: 335/30ZR18 mounted on 18x12.0 (18mm offset)
But keep in mind this tire set does not alleviate the availability problem that exists for tires in those sizes.

(3) Another wheel solution (one that Debbie and I promote) is to:

• Purchase and install longer wheel studs (available from Pantera vendors)
• Purchase "off-the-shelf" one piece cast wheels from Enkei or TSW. These wheels are high quality, manufactured in either Japan (Enkei) or Europe (TSW); they are also lightweight, and strong. They are available inexpensively on eBay and Amazon.
• Adjust the offset using hub and wheel-centric spacers. Custom billet aluminum spacers up to 30mm thick are available from several companies, including Motorsport Tech.

Even factoring-in the price of studs and spacers (about $800 USD) the overall price of a wheel package such as this is still substantially below other options.

If nothing else perhaps I've given some folks food for thought.

Apologies for my prolixity.

I have 17 clones and a nice low stance IMHO (adjustable shocks)

But I also liked the 15" on my previous Pantera. Hell, I like Panteras!

quote:

Originally posted by No Quarter:

Hell, I like Panteras!

 Right on!

quote:

Originally posted by Clockwork:

... Mikael those 17"s look really nice ...

Agreed!

quote:

Originally posted by David_Nunn:

.... George, I don't enjoy voicing an opinion contrary to yours …

David, you are more than welcome to disagree with me. The respect you expressed is appreciated. But don't apologize for having a differing opinion. I appreciate and value your opinions, experience and the knowledge you've gained along the path of De Tomaso ownership. I'm sure other members do as well. As members of a community we all learn from each other, and we all disagree from time to time.

And at the end of the day ...

-G

Select tires for the front of your narrow body Pantera which are 24" to 25" OD, 225 to 245 cross-section.

It is a common mistake to try and set the front tires too far outward, closer to the fender lip. What happens is you'll end up with a tire that rubs the fender lip in high speed corners.

225mm front tire: 6mm offset - 7.5 inch wheel (20mm recessed)
235mm front tire: 11mm offset - 8 inch wheel (20mm recessed)
245mm front tire: 16mm offset - 8.5 inch wheel (20mm recessed)

8" wide Campy clone wheels (Pantera East) are designed with 23mm offset, 9" wide Kinesis wheels are designed with 25mm offset.
________________________________________________________________

Select tires for the rear of your narrow body Pantera which are 26" to 27" OD. My personal preference is a tire in the range of 275mm to 295mm cross-section. The exact cross-section depends upon the tire's availability and its outside diameter. 

Others prefer tires in the range of 315mm to 335mm cross-section. Neither choice is wrong, each person knows what's best for them, or will learn from experience. The outside diameter of 315mm tires are an issue for me. 6018 had a set of them when I purchased it, I felt they were way too small for the fender opening.

275mm rear tire: 8mm offset - 9.5 inch wheel (20mm recessed)
285mm rear tire: 13mm offset - 10 inch wheel (20mm recessed)
295mm rear tire: 18mm offset - 10.5 inch wheel (20mm recessed)
315/35R17 rear tire: 12mm offset - 11 inch wheel (4mm recessed)
335/35R17 rear tire: 12mm offset - 11 inch wheel (protrudes 6mm)
335/30R18 rear tire: 18mm offset - 12 inch wheel (flush)
325/30R19 rear tire: 13mm offset - 11.5 inch wheel (flush)
335/25R20 rear tire: 18mm offset - 12 inch wheel (flush)

-G

ttam23, I have Michelin Pilot Sport, 235/40 ZR 17 and 335/35 ZR 17 on a narrow body Pantera with a low stance. No rubbing issues except the rear part of the front inner fender when steering wheel is turned max. Fender lips are rolled, I don't know if the tires would rub if fender lips weren't rolled

I have read this post multiple times and every time I get dizzy! I use to work with dimensions and rattling off reams of figures was the norm, but nothing as boggling as this.

I think I have begun to grasp the concept of wheel offsets, tire widths and possibility of scrubbing, but I just wanted to verify the few basics, please correct me if I am wrong

To me, offset is the value of a wheel I am interested in and to determine it, I can easily measure wheel width and backspace.
offset = backspace - wheel width/2.

The wheels bolt to the lug stud flanges and this width should be the starting point for any wheel evaluations. From online sources, I found the front track given as 57” with the OEM 7” Campy’s and their 0.25” offset. From this I gather the front flange to flange width would be 57.5”. Is this correct thinking?
Track = 57.5” - 2 X offset

Using the track and the tire sectional width, I can figure a tire outside width. For the OEM with 185s, that would be 64.3”.
Outside = Track + sectional/25.4

If correct in my thinking, I can use the flange width and the offset of the desired wheel to figure the new track. For example, in George’s post with the wheel table, he stated the 8” clone Campy’s had an offset of 0.86”, thus given a new track of 55.8”. With a 245 tire, one can expect rubs. This combo would have a width of 65.4” (or have the tire about 0.6” farther out than OEM combo). Going with the 9” clone and its 1” offset, the outside width would reduce to 65.1” and be OK.

My comparison of using the OEM 8” with their 0.75 offset reduces the track to 56” and with the OEM 225 tires had the outside width of only 64.9”.

So it appears to me that an outside tire width of less than 65.4” is the limit. I am still dreaming I’ll use the OEM wheels, but this implies that the BFGoodrich TA 215/60r15 93S for 7” I was considering might scrub with its outside width of 65.5”

(oh, I did make an excel sheet to do the crunching)

Here you go.

Another angle.

quote:

Originally posted by Garvino: Anyone have a side profile picture of a Pantera running 18" front and 19" rear wheels? Thanks in advance. Devin

Kinesis K29s

Best,
K

18/19

The front & rear wheel arches & chassis of each Pantera model are designed for tires of specific diameters.

In this picture 6018 had 18" front tires (245/35ZR18) 20" rear tires (325/25ZR20). It has an Amerisport front spoiler. The lower rear control arms are level with the road, notice how well the rear tires are centered in the rear wheel arches with the control arms set that way. The front end has been lowered until the chassis is level. Since the difference in tire diameter front to rear is 1.65" (less than 2") the front tires are not centered in the front wheel arches, the tops of the wheel arches overlap the tops of the front tires. But I don't think anyone would accuse 6018 of looking too high, which is why I'm replying to your post.

If the back tires had been a little larger in diameter, closer to 27" OD, they would have filled the rear wheel arches even better than the 325's did, the rear of the car would have been higher, to level the chassis would have required raising the front of the car. That would have centered the front tires in the front wheel arches better. And the diameter of both sets of tires, front & rear, would have filled the wheel arches relatively evenly. After that, you have to consider wheel off-sets, not only for suspension geometry & rubbing concerns, but for cosmetic concerns too. You want both sets of tires to be inset from the edge of the fenders about the same. Otherwise it looks wrong. Looking at the side view of 6018, the front tires are inset more than the rear tires.

Regarding wide bodies, the ideal cosmetic "stance" of Group 4 replicas are similar to narrow body Panteras. BUT ... GT5 & GT5-S Panteras need front & rear tires which are closer to 24" diameter front & 24.5" diameter rear, because that's how the wheel arches were designed. But its not possible to find modern tires in such small diameter. So with the GT5 & 5-S don't lock yourself into the frame of mind looking for the widest tires, balance that with tire diameter. You're gonna want front tires in the 24.5" to 25" diameter range, and rear tires that are 1/2" larger in diameter than the fronts.

-G

quote:

Originally posted by Garvino: Panterror, Wow - those rear wheels are wide. I bet they look awesome. Thanks for the information.
Devin

......Do these wheels make my butt look big?

K

For 14 years #6007 ran with BFG TA 275/60R15 rears and 205/60R15 fronts. Rears looked way too tall IMO so using this thread I decided on 255/60R15 rears and retained the 205/60R15 fronts.

And 255/60R15's & 205/60R15's

quote:

Originally posted by JFB #05177:
the BFG's 255/60R15 & 205/60R15 is my planned choice.

How about photos when you get them on the car

Here you go JFB

keep it low, 18's all around.

Hi All,

I finally have to upgrade the old 15" wheels on my Pantera (hard to get rubber - plus one of the wheels is leaking). I'm most interested in Chip Fooses's new Pantera wheel design, with the gold center to highlight my car's green paint.

Foose has now changed the tire recommendation for their 18x8"/19x11" wheels. They now recommend 225/40-18 and 285/35-19 for "a better fitment".

Does anyone know the specifics as to why they changed their recommendations?

Craig Cline
THPNPU07352

Craig,

My guess (and that is all it is) is due to tight tolerances and fitment/rubbing issues.

Although I did not go with the Foose wheel I did go with the size he ran on his car - 18x9 & 19x11 wheels wrapped in 245/35/18 & 325/30/19 tires.

I fought getting the correct offset on the front wheels due to rubbing at full scrub and eventually fabricated a new windshield wiper motor cover under the passenger front wheel due to tolerance issues. I initially thought I may have to roll the front fender farther forward (towards the nose) but ended up not having to after getting the correct offset. The factory roll on the front fender sufficed.

With the rear wheels I had to roll the fenders a bit to get the tires not to rub.

From an online tire size calculator it appears that the difference in Foose's tire size (on his red show car) on the front tires is 9.6" versus 8.9"(his new recommendation). Likewise, the rear tires went from 12.8" wide to 11.2".

By the way, I ended up buying a tool that allowed me measure the offset needed for the actual tire I was planning on running. I mounted the tire on the tool, adjusted the offset, mounted the tool and tire to the car hub, and ran the suspension and/or steering through its paces...adjusting the offset until I found that sweet spot. Then there was no guess work involved.

Just my two cents....or maybe the other tires are easier to get???

Devin

Here are the specs for the Forgeline Motorsport wheels that were built for my car.

Front Wheels
18” X 9”
Offset 19.05 mm
Back spacing 5.75
62 mm center bore

Rear Wheels
19” X 11”
Offset 12.7 mm
Back spacing 6.5
62 mm center bore

I did not have a chance to run to my shop today but I found these pictures on my phone this evening. The photos with the tires mounted don't have the center caps mounted - sorry.

To all the Pantera wheel offset experts:

As I posted previously, my old 15" Gotti wheels have finally given up the ghost, so I'm researching new replacements.

My question is about front wheel offsets.

I like the way my old wheels, with their 225/50-15 tires, fit in the front wheel wells. And they've never rubbed in all the years I've had them on the car.

I measured my current 15x8" fronts wheels, and they have a 4.5" backspacing, which calculates to a 0 offset.

All of the 17" and 18" front wheel offsets that I have seen (for the same 8" widths) vary from 12mm (5.0" backspacing) to as much as 22mm (5.375" backspacing).

Why do the new wheels need so much more positive offset (added back spacing) compared to my old wheels? I know my old tires are short at only 24", but the 17-18" replacements are only 0.5" to 1.0" taller. And if I stick to 225/235 replacements, they are at most only 0.5" wider.

Slightly Confused
Craig

quote:

Originally posted by CraigCline:

... Why do the new wheels need so much more positive offset (added back spacing) compared to my old wheels ...

Good question Craig. As a generalization most aftermarket Pantera wheels are built with too much front offset and too little rear offset. The front wheels are 8 to 9 inches wide and have 22mm to 25mm offset. A 245mm tire rubs the inner wheel house, and looks excessively recessed. By contrast the rear tires are generally offset to be flush with the fender edge; in fact the 335/35R17 tires stick-out from the fender by 5mm! Then the level ride of the chassis is upset because the rear tires are generally much smaller than OEM, so the rear end must be jacked-up or the front end lowered. You end up with a front tire that fills the fender arch as intended, but a rear tire that has a big gap between it and the fender arch. So the appearance of the tires is imbalanced front to rear in two ways, the amount they are recessed by offset, and by the gap between the tires and the fender arches. On top of that, the front tires are not centered within the fender arches, they are shoved forward. Correcting these things has been a crusade of mine.

Yes small diameter tires and the vehicle's ride height both impact tire clearance. I recommend 6mm offset for 225mm front tires, and 16mm offset for 245mm front tires.

I have a wheel width and offset guide I'll attach below.

quote:

Originally posted by Garvino:

... Let me know if I can be of any further assistance ...

Devin thanks again. You've been a great help. Very cool that you are helping the school with the kids.

I agree with you regarding the appearance of a "small" amount of tire recess. Emphasis on the word small (20mm?). Its also a very practical choice. I'm also excited that you were seeking the same recess front and rear, something I've been harping about for a long time. Finally I'm happy to see somebody "buck" the trend and use something less that 22mm to 25mm front offset.

#6018 has been my guinea pig, and it seems there is some variation between our Panteras. The 325mm rear tires previously installed on 6018, mounted on wheels with 12mm offset, were flush with the top of the fender lip, not recessed. I wonder if that might be due to the tires themselves, as I used Michelins PS2's, and they were very wide. Whatever the explanation, it is a lesson for everyone to keep in mind.

----

Finally I'd like to comment about the Pantera's front caster. If you take a look at any Pantera in which Ford reduced caster to about 3 degrees, you'll notice immediately that the front tires are not centered in the fender opening, they are pushed forward. This resulted when Ford moved the upper front ball joints forward about 1/2 inch in order to cut caster in half.

If an owner moves the upper front ball joints rearward 1/2 inch in order to increase caster, restoring it in the range of 5 to 6 degrees, it centers the tires in the fender openings AND looks much better. There shall be no increases in rubbing in as much as the tires are positioned (centered) in the wheel wells as they had been originally intended. If there's any tire rubbing it will be on the inner wheel house, and only with the widest 245mm tires, because the vendors insist upon 22mm to 25mm offset. And even then its only during full lock parking lot maneuvers, nothing dramatic.

Besides appearance the increase in caster improves forward stability, and what is less understood is that cornering "bite" improves as well, because the front tires "lean" into corners more. Ford reduced caster to reduce "bite" and increase understeer. Ford "dumbed down" the Pantera chassis in this way because they believed their customers could not cope with the full capabilities of the chassis (i.e. the immediate response to driver input).

In terms of chassis response to driver input I personally want more! That's why I am a sports car enthusiast. Therefore from my perspective Ford's decision made no sense at all back then ... nor to this day. I don't want to revise the Pantera chassis to make it something better than it was intended to be, but whatever capabilities it was intended to have, I want them all ... undiluted by corporate Ford's committee made decisions.

Craig here's the wheel width and offset guide.

Norm

The wheels you have are obviously not OEM. I suspect they are Pantera East or perhaps Wilkinson wheels. If a tire set is not available via Tire Rack or On-Line Tires then stack your 16 inch and 17 inch wheels in the garage and opt for a more modern tire set in sizes that will be available for a while.

We can't help with a wide range of custom sizes, but as a club we do our best to guide owners towards modern sizes that will best replace the OEM tires. Maybe this little chart we've put together will help … maybe not. But we exist to help you one way or the other. Debbie and I guarantee nobody has put more effort into this subject than we have.

Be careful using Tire Rack's size search function. It misses lots of combinations.

Here a few close up pics of the wheels I purchased from Dave Rittenhouse.  These are the wheels Boyd made for Pantera East.

Jimmy,

Is the wheel in the pics a 17" or an 18"?  

If I recall, you have 17" on the front and 18" on the rear. Does American Republic use the same center on 17" and 18" but with a larger step in the rim for the 18" or do they use a larger center for the 18"? 

Hi David, the wheels in the pictures are both sizes.  You are correct that the fronts are 17’s and the backs are 18’s.  

Another member wanted some info so I thought I would post some close up shots of the wheels.

I believe that the centers are different sizes but am not totally  sure.  I can’t check right now as the car had a few minor issues so it is at my friends shop.

I also want to say many thanks for the help in answering some of my questions along the way.  It was greatly appreciated.  Thanks again David.

I can't believe I read this entire thread. My eyes are hammered. Now I have to think about a lot of stuff.

If you figure out a source for a nice looking set of FR500 style (or anything else) that fit a narrowbody car, looks cool, that you can get modern, performance tires for, and doesn't cost over 6-7K for the set, please post up the vendor, wheel specs, and estimated price!

I'm sure a lot of people would appreciate it!

Thanks!

Rocky

Hi

I now beleive the 285/50R15 P7 has actually been produced. I also beleive they are currently in a lorry on their way to Longstone Tyres! which is great news.

They will be on here soon https://www.longstonetyres.co....aso/pantera.html?p=2

Of course i will post on here again when they get here. How exciting, but blimey iot has taken some time, but the Pandemic has cost us an extra 2 years, and i do have other projects in with Pirelli that have just been put on the back burner so it will be great to get these.

i am relatively confident i will be able to keep the price sensible.

It would be great if people could post pictures of their cars fitting these new tyres that they are happy with us using in our advertising or on our web site. (we will fudge out your registration plate to make it a bit annonymous)

Going to run 335/35/17 MICHELIN - possibly on a 13.0 or 13.5 rear and 255/40/17 MICHELIN - possibly on a 10.0 or 10.5 on a factory GT5 with all the GT5 plastic removed and rivet on GT4 flares.  Not sure what rims yet - - but looking to possibly use centre lock BBS.   Rear tyres took some finding - fronts are a 2 -3 month wait.

According to the literature I found 13 inches would be the widest recommended rim, very common width for the 335 is an 11 inch width.

Larry

You need a 13.0 - 14.0 inch wide rim to fill original fiberglass GP IV flares depending on the backspacing you select.  The 335 17 is narrow in width compared to the 345/35/15 I run.  Measure multiple times and cut once to get the right look.   I have seen 335 tires on too narrow a rim with literally no back space attempting to fill the flare.  Remember the factory GP IV cars use a 14” rim.  

@lf-tp2511 posted:

According to the literature I found 13 inches would be the widest recommended rim, very common width for the 335 is an 11 inch width.

Larry

Larry, an 11" rim isn't ideal for a 335 width tire; however, it is acceptable. Increasing the width of a 2 piece wheel to 11.5", 12" or wider costs considerably more than an 11" wide wheel. That's because the company that supplies rims to Wilkinson, Coddington, American Republic, etc., make an 11" rim but nothing wider. If you want a wider rim, it involves cutting 2 rims in half and welding them back together, to give the width and offset you want.

Thanks all for the suggestions.  11.0" is way too narrow for my purpose, pulls the sidewalls in too much and seems to be often used as a sort of a 'cheat' (for want of a better term) on a narrow bodied car (on my narrow GTS - I am sticking with 15" - PIRELLI CINTURATO) - this is not a narrow body, currently a factory GT5 - going to GT4.  Yes - the car currently has 345/35/15 as per factory GT5 (I wish someone made a 345 in suitable 17"), but I want to get away from the 15.0".  I have seen a 335/35/17 on a 14.0" - but in my opinion, too much of the rim was hanging outside the sidewall.  When I physically have the 335/35/17 in my hands (after the holiday break) - I will be experimenting, and expect at 'worst' - the rim will need to be 13.0" - at 'best' - I am expecting 13.5" - yes slightly narrower than what I 'dream' of - as being able to run a 14.0" - but the 14.0" seems just a tad too wide for the 335 carcass.  HA - by "...measure multiple times..." - I assume you mean -'measure ONE THOUSAND TIMES BEFORE CUTTING' - HA - for whatever cutting is required - I will be measuring multiple multiple times - leaving it - coming back the next day - measuring multiple multiple times again - and then doing what is required.  My biggest 'headache' - is figuring out a safe way to remove the factory bonded GT5 flares without causing any damage - they are genuine factory plastic parts and I prefer no remove them undamaged.  I also intend to run the car as low as I can - that may also cause me a few headaches - and is one reason that I may go from a 255/40/17 on the front to a 245/40/17 - but only time will tell.  HA - I have seen a 335 on 15.0" rim - but way too much stretch and only suitable for fad type events.  The BBS rims will be multiple piece, and hence  I can juggle the width of the hoops to create either the 13.0" or 13.5" (HA - and dream of a 14.0") - HA - following the old saying - "it is only money".

Firstly, why oh why convert a 9000 series GT5 to a Group 4! The factory GT5 is a rare car, likely as few made as GT5-S!

I run aftermarket 17" rims on my factory GT5, apart from the diameter they follow the specs of the GT5/5S 10 spoke Campi's for width and backspacing with 13" rears and 10" up front. Tires are Michelin Pilot Sports 335/35 rear and 275/40 up front. IMO they work great, fill the flares as they should. They are higher profile than OEM tires, so cause the car to sit higher, I have the suspension set as low as I can go and as a result have some cracking on the front flares from tire rub.

"Firstly, why oh why convert a 9000 series GT5 to a Group 4! The factory GT5 is a rare car, likely as few made as GT5-S!" -- Firstly - I do not care what you think of what I do my my cars - HA - my car - my money  - my choice.  I am also getting rid of the hideous Italian lounge chairs - AKA - the bucket seats - pulling the factory 351 and installing an all aluminium 434 CLEVELAND (when the DAMN block becomes available) with 8-stack EFI and HALTECH engine management - and I could not care if it was the most rare PANTERA on earth, I do not 'collect' cars for investment - I 'collect' and build to want I want - not to satisfy some 'collector//investor' mindset.  I have never liked the GT5 all that much from all angles - hence back to GT4 - which in my opinion is a more clean wide look.  And understand re the 275 being a bit too tall on the front - hopefully either the 255/40/17 or 245/40/17 solves my problem.

I totally understand, each to his own, your money your choice how you spend it. Where are you located? I would take those hideous lounge chairs off your hands!

Pirelli make a 245, 255, and 335 in the 17" P Zero.  They also make a 335 in the 18". Consider overall tire height as well in your calculations.  

Yes – advice re tyre height is well accepted – unfortunately – if one decides to play around with larger diameter rims – DAMN tyre sizing can then quickly ‘ruin your day’ - HA.  I hope to end up with the sizes listed for the MICHELIN 335/35/17 @ 26.0” rear overall height – and MICHELIN 255/40/17 @ 25.0” front overall height (not sure if I can get a matching 245/40/17 – otherwise I would test fit a set of those to the front) and I will be running 4.62 gears.

Re anyone modifying their car – I often cringe at the wheels and spoilers and other ‘bling’ that many people install on their car – but – it is their car, they can cover it in pink shag pile carpet for all I care – HA. And I believe we are members of the ‘PANTERA CLUB’ (for want of a better term) where we do not have a ‘spasm’ like the FERRARI club seems to have if a line up of absolutely identical red cars has a different valve cap – HA.  PANTERA like LAMBORGHINI (HA – yes – I modified that a well) are what I call exotic hotrods and you do what you want – it is your car and you can do what you want without other people having a ‘spasm’ over changes.

HA – I missed out on an F40 some years ago – and yes – I was going to modify that too – HA – no doubt I would not be typing this now as some lunatic from the FERRARI club would have had me shot – HA.

The GTS of one of my sons, it looks dead stock outside with CINTURATO 225/50/15 and 285/50/15 and mostly stock interior – the only major changes are the mechanical specifications – engine mainly.  HA – one change I do to all our vehicles – pull the stupid radio//tape//CD players out.  The exhaust is the ONLY music required in these cars for me – HA.

Rethe horrible Italian lounge chairs (AKA – the bucket seats) and all the other parts I will be removing from my cars – all factory parts will be carefully wrapped and stored for the day I die and then my boys can either decide to drive my cars as I left them, or they can return to factory specifications.  Same as the matching engines, the factory engines will all be properly put into long term storage, and one day if they decide 750.0 hp is too much, they can always install the somewhat slower factory engines – HA.

Whether someone decides to turn their L into a GT5 clone, or turn a GT5 into an L clone – that is their choice.  Such is life.

Re my GT5 to GT4 – I see my biggest headache (other than making sure I do not damage the factory parts when removing them) – is making sure that the GT4 flares are an accurate fit (as one can get) and modern quality construction.  Everyone says “my flares are perfect’ – but that is often with a hand over one eye and the other eye closed – HA.

I hope to find a red Si to purchase – and I intend to change the factory 17.0” rims out to 18.0” rims on that.  My ‘theory’ at this stage - is to have the factory Si rims copied in 18.0” – exact same offset – same color finish.  The rather low-performance 302 cu in will be replaced with a 427 cu in.

Hi all. New to the Pantera world. Looking to have custom wheels made for my 74 that has gts style fairings on it. I’ve read all 4 pages of info and feel dumber than when I started! Lol. The wheels would be 18x8 and 18x12. I need help with backspacing. Want the deep recessed look in the rear.

Mike,

I'd only be guessing, because you have GTS fender flares and I'm really only familiar with the dimensions that work on a stock bodied Pantera. Dennis Quella told me, with aftermarket GTS flares, you can add about 1-3/8" to the outer dimension. Another vendor with GTS flare expertise is Ron McCall. I have photos (below) of a GTS bodied Pantera he built and the dish on the rear wheels was HUGE! I'd send him a PM. Looks like you have the same wheels. Perhaps yours could be "re-rimmed". Also, why only 8" and 12" wide? You could go an inch wider, front and back, without difficulty. What tire sizes will you be using?

Davidnunn

thank you for reaching out to them.
Just doing online searches brought me to those width wheels. Even though it’s flaired, there is a pretty big return lip on both front and rear. My thoughts on tire size are 245/35-18 and 335/30-18.

Thanks again

You must have OEM style GTS flares. Are they fiberglass? The tire sizes you mentioned are perfect but I'd suggest 8-1/2" or 9" front and 12" or 12-1/2" rear. 13" works too but stretches the tire out a bit.

They are fiberglass, molded in, not exterior fastened.

Mike,

If the photos are your black car measuring the existing wheels would be a great start, then you can measure where you want the new wheels to sit in the flare and it should come down to some simple math.

Hello everyone.  I am sure that I am not the only one that goes through 'wheel and tyre dimension anxiety' each time they are putting a new project together, but in an effort to hopefully ease my 'wheel and tyre dimension anxiety' a bit (HA - hopefully), I am ordering a tool that I have found online that can be used to calculate offset and also check tyre clearance.  I have no personal experience with using such a tool, but as soon as I figure out how to use it (HA - my 'weakness' is never reading instructions properly), I will post my experience with it.  There are multiple manufacturers of such devices, but until I receive mine and gain some experience with it, I prefer not mention the brand I am going to use.  I do not expect any 'surprises' with it as all the different brands seem to do the same thing, and all seem to do it successfully.  CHEERS from AUSTRALIA.

@MikeSchill posted:

Hi all. New to the Pantera world. Looking to have custom wheels made for my 74 that has gts style fairings on it. I’ve read all 4 pages of info and feel dumber than when I started! Lol. The wheels would be 18x8 and 18x12. I need help with backspacing. Want the deep recessed look in the rear.

Your car has a great stance and those wheels are really nice. What size are they?  

tajon.
Thanks. The current wheels are 17x8 and 17x11. I’ll be putting them up for sale once I figure out the new set.

If you like the centers of your current wheels, as they are 3 piece you could simply get new outer hoops to widen and bring them out further.

These are made by SIMMONS in AUSTRALIA (simmonswheels.com.au) - this is a 17" version.  They make them in a range of diameter, width and colors.  SIMMONS has been around for many decades and make quality products. I purchased my first set of SIMMONS near on 35-years ago, and they are still going strong on the car I sold.   They also have other designs.

So I finally had time to pull the wheels and do some measurements. Current setup is 17x9 with 6” backspace (+1” offset)

17x11 with 6” backspace (-1/2” offset).  I’m thinking of upping the to 18x9 and keeping same dimensions due to the 245/35-18 being a little wider tire. The existing setup is pretty close to full turn fender rub about 1/2”    The rears 18x12 with 6” backspace would push the tire closer to flush of fender lip. Can’t really go wider or pull wheel in more because it’s already close to exhaust pipe and 335/30-18 should work. The car has adjustable coil overs on all corners and wilwood disk brake conversion all around.
Do my calculations look correct?

To be clear with builder 62 mm bore and 5x4.50 bolt pattern?

Thanks

Did you guys know Pirelli have made this tyre again?

https://www.longstonetyres.co....li-cinturato-p7.html

Making the 15" wheels a viable option again.

Yes, and Lucas Classic Tires out of California have them in stock.

https://www.lucasclassictires....NTURATO-P7-4572L.htm

HA - I wish PIRELLI made a 345/35/17.

@Moby935 posted:

HA - I wish PIRELLI made a 345/35/17.

Hi

But they will be 2" too tall