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

IMG_7877mr

Attachments

Photos (1)
One detail that may become a pain late in your Pantera adventure is, adding extra caster to the front wheels to cure tram-lining and instability at high speeds will pull the wheels & tires back toward the cabin. If you buy max-sized wheels & tires, fit them almost as a slip-fit to the fender openings and then try tweeking the handling as a final stage, you may find the right tire again hits the wiper motor cover, the left tire touches a cowl drainage tube and generally, there may be little rub-areas all around the front wheel area, when at full lock one way or the other. The left & right tires will NOT necessarily be perfectly aligned the same with the two fender openings either, as the multiple frame jigs the factory used were apparently not exact copies nor perfect mirror images. And of course, front frame movement from 45 yrs of use, crash damage (even minor), lowering to taste and other things can change clearances when 5X-or more- tires are fitted. Tires also vary in exact dimensions from different mfgrs or even between tire models from the same maker.

To a lesser degree, the same goes when fitting giant rear tires. Best to leave extra clearance in excess of what George mentioned, or do all your handling & appearance updates before buying those max-size wheels & tires. Trading wheels & tires or flaring a fender for enough tire clearance on a 'finished' Pantera WILL be expensive!

I'm reminded of the owner that had his Pantera extensively pro-redone at enormous cost, bought big tires & wheels, drove the finished machine for a month and found that it's stock brakes were no longer adequate and 'looked funny' with the huge wheels & tires. But oversized brakes would not fit the wheel sizes he'd bought! He nearly gave his almost-new aftermarket wheels & tires away, and took a bath on prices for even larger ones when upgrading the brakes. Redesigning a car is a many-aspects thing....
George,

Sorry for the delayed response - I have been off the grid at the Teton Science School outside of Jackson Hole, Wyoming with my son's class as a chaperone.

As per your question, both the front and rear tires on my new wheels are slightly tucked in from the outermost fender lip area (visually about the same amount on front and rear).

I did this on purpose because I like that look more than the tire and wheel being exactly even with the fender lip (just my preference).

Just as Bosswrench mentioned, my car was not exactly even on the front end. The front passenger hub sits slightly farther out towards the fender compared to the driver's side hub. It is not noticeable visually but I figured it out when I started measuring for the new wheels.

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

Devin
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. Thumbs Up!

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.

Pantera wheels specs

Attachments

Photos (1)
I have read all of this sticky and looked at several tire manufacturers but can't find replacements for the combo I have.
My car has stock looking 2 slot wheels with 225/50/ZR16 tires on the front and 315/35/ZR17 on the rear. The existing tires are BFG G-Force TA KD.
I haven't been able to find anywhere to get the same type/brand tires for front and rear. Anyone know what options I have. What I am running fit and clear fine.
Thanks
Norm
I think the only thing you'll find in a matched set are Pirelli P-Zero System but you'll have to go slightly larger on the rear (335/35-17).

If you NEVER drive your Pantera in the rain, you can get 225/45-16 or 245/45-16, paired with a 315/35-17, in a Toyo Proxes R888R. It's an autocross tire so it won't last very long but you'll have fun in the meantime. I hesitate to even mention a competition tire for the street but some people seem to be OK with it.

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.

Pantera_tire_sets

Attachments

Photos (1)
Norm, IMO ... those tires won't work well together at all. If you're going to mix tires, front and rear, you should choose tires that at least have the same traction and rubber characteristics. Pay attention to the UTQG ratings. They are just a guide and not 100% accurate but at least they give you an idea what the tire is all about, as far as rubber compound is concerned. The Michelin Pilot Sport PS2 is a great tire with a UTQG rating of 220 AA A. You should try to find a front tire with the same UTQG, or as close as possible. The Michelin Pilot Sport A/S 3+ has a treadwear rating more than double that of the PS2 (500). A UTQG of 200 AA A or 240 AA A should be OK too. A 200 A A, 220 A A or 240 A A would also be OK. For the sake of aesthetics, try to find a front tire with a similar tread pattern.
This is tough. I don't think I would want the pure race Toyo Proxies R888R suggested but I did find the Toyo Proxies R1R with sizes 225/45ZR16 and 275/40ZR17. What do you guys think. Are Toyo tires any good? I replaced a set on another car I bought that had a serious right pull, with Michelins and the pull went away. Alignment was OK and not changed.
Norm, Toyo’s are great but a 275 width is pretty small for an 11” rim (which I assume you have). A better option would be Continental Extreme Sport (225/50-16 & 285/40-17). That being said, the Pirelli P-Zero System combo is still the best for you. I realize they’re expensive but so’s your Pantera.
UTQG numbers are supplied by the manufacturer, so they're always taken with a "grain of salt". All you can really gather from the two tires you mentioned is that the P-Zeros have a softer rubber compound than the Continentals. They are both good tires but I believe the Pirelli's are better suited to your rim widths. I recall seeing the 335/35-17 P-Zero's for $488 each, I just can't remember where. Maybe the Tire Rack will let you have them for that. Get them before the sale ends (June 4th).
quote:

I can get Michelin Pilot Sport A/S 3+ in 225/50ZR16 and Pilot Sport PS2 in 335/35ZR17. Would this mix of tire types work OK?


What about Michelin Pilot Super Sports they have a tread pattern quite similar to the PS2's. I have used them in a 17 inch size but not sure if they come in 16's.
Warning: several owners invested in 16" front wheels and tires, and then found that so-called 'big brakes' would not fit inside 16" wheels. If you think you need both giant tires and big brakes, choosing 16" wheels can be a VERY expensive mistake!

Personally, I think smaller OD front wheels look better on most Panteras, but that's just me. I can lock max-width (with unflared fenders) 245-50 x15" front tires with "small" brakes, so the extra money for big brakes went somewhere else (and with a Pantera, there's ALWAYS 'somewhere else'!)
An update on what I did. I have the 16x8 fronts and 17x11 rear wheels. My existing fronts were 225/50/ZR16 and rears were 315/35/ZR17. I could only get a finger between the rears and mufflers so couldn't go to 335 size. Couldn't find sets of 225 front and 315 for rear. I switched to 285/40/ZR17 for rears which are slightly bigger diameter but narrower. I could only find these sizes as sets in Continental and Pirelli P-Zero. I bought the Pirelli P-Zeros as listed in the Tire Rack P-Zero System. They are Asimmetrico. The fronts are listed as N3(Porsche) for 8" rims. Both UTGs are 140AA.
I have installed the new tires (actually bought thru my local Tire Factory store). They are fine. The rears, although narrower tread width, look great, maybe better.
Hope this update for these sizes helps someone.
Thanks for all your help with info.
Norm

Add Reply

Likes (0)
Post
×
×
×
×