DICK RUZZIN / 12-1-2013
This is my replacement tire program analysis.
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The first step for me was to choose a brand as a reference. There may be other brands to choose from for the sizes finally chosen but I have not gone that far yet. Ultra high speed is no problem as I do not go there. I drive my car usually in good weather on public highways, no racing or gymkhanas.
B F Goodrich is a respected brand that has a wide variety of 15 inch tires in many aspect ratios so for a number of reasons I chose them as the program study base. I did include other sizes from Mickey Thompson but those tires were configured for drag racing on the street.
MY GOALS:
1. Tires from a brand that have a good performance record, BFG has that, others might also.
2. Reduce the space between the top of the rear tire and the wheel opening above it.
3. Achieve a size differential between front and rear that is clearly discernible, both in side view height and cross section volume.
4. Lower my car front and rear, I have a 1 inch spacer on top of my rear shock that can be removed.
5. No deterioration in speed rating from my Good Year Eagles.
6. Good handling and braking qualities for street tires.
I am able to achieve all of the above by using BFG tires, front and rear.
I set up a gridded drawing and recorded diameter dimensions for the following
BF GOODRICH and MICKEY THOMPSON tires, to be used front and rear. Each vertical line that represented a tires diameter also depicted the location of the bottom of the bell-housing that defines rear road clearance. The bell-housing travels vertically with the wheel centerlines which moves up and down with the overall tire diameter.
THE FOLLOWING SIZES WERE CONSIDERED AND DIMENSIONALLY EVALUATED,
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FRONT:
225X50
225X60
225X50 (Mickey Thompson)
235X60 (Current, Good Year)
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REAR:
255X70
295X65 (Mickey Thompson)
275X60 (Current, Good Year)
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The following choices resulted in the best solution for me..
FRONT:
225X60 with a 9.0 inch section.
This tire is slightly smaller in diameter as well as slightly narrower than my current 235X60 front tires. The current front tire looks too big in relation to the 275x60 rears. The 225X60s will lower the front 4/10s of an inch.
REAR:
255X70 with a 10.2 inch section.
This tire is 1.1 inches larger in diameter than my current 275X60 tires and it gives me 5 inches of rear road clearance. It also reduces the space between the top of the rear tire and the top of the rear wheel opening to 1 3/4 inches. I can also remove the 1 inch spacer on my rear shocks, resulting in 4 1/8 inches of road clearance and reducing the space above the tire to wheel opening to 3/4 of an inch.
I am currently searching for other brands that will have these sizes.
All the best,
Dick Ruzzin.
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dickruzzinDESIGN@aol.com / Phone: 313-824-0539
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