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If you changed from the original donor car wheel and tire size, why did you change and what did you pick?

Was it performance based? Was it appearance based? Was it cost based? What wheel and tire did you choose?

There are some good answers above.

If you listen to Caterham 13" wheels are what you use if you wanna go fast (Ricky Bobby nod)

This Caterham exclusive design, has an additional heat treatment strengthening process during manufacture that has enabled us to make the wheel lighter than all but the 13" magnesium wheel, supplied as standard on the R500. This gives it handling comparable to a 13" wheel, combined with the aesthetic benefits of a large diameter wheel and low profile tyre. Nevertheless, because the Seven is so light, large diameter brake discs are not required. This means that 13" wheels can be used, giving the associated benefits of low rotational inertia (see in 'construction' for an explanation), so in general the best wheel size for the Seven is 13". It is no coincidence that the Superlight R500, and all Caterham race-cars run on 13" wheels. With a choice of rims, the 13" wheel offers the best unsprung weight, tyre choice and tyre wall aspect, although adjustable spring platforms may need to be fitted to ensure sufficient ground clearance. We strongly recommend the use of 13" wheels to achieve the best on-track performance from the car. To this end, all the following information assumes the use of this size wheel.

with the appropriate sized tire of course.

I hope that clears up the question.

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Engineer: noun en·gi·neer \ˌen-jə-ˈnir\ - Someone who does precision guesswork based on unreliable data provided by those of questionable knowledge. (See also: wizard, magician, sorcerer, witch, miracle worker)

Same here. 205/50r15 is a cheap size with lots of offerings. And it's close to the Civic tire size, so you know there is going to be decent tire selection for a long time. There are plenty of 15" 200 treadwear tires, and also lots of Rcomps. Also similar diameter (eg. 225/45r15) but wider available.

Rims are in the 8-11lb range which is pretty light, and they are cheap. You can also fit all the brakes you could possibly need under 15".

End of the day the most cost-effective, multi-use size is 15". 13" is fine if only running Rcomps. Lots of selection, but few street tires.

I always suggest to run affordable tires/wheels..... it's way more fun if you can afford to replace them every year or two rather than missing events because you're broke and have no tires left.

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Build log: viewtopic.php?t=9291

Wanted to add that the only tire I've wanted to run that is not available in 15" is the Conti DW. Good wet weather tire. However, the Kumho 4X fills that role nicely...... and is much cheaper.

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Build log: viewtopic.php?t=9291

My "Trick-6" toy is getting 14" Compomotive wheels from an Alfa-Romeo in place of the old damaged 13" mags.
They are the desired 4x108 PCD and lighter wheels.
14" performance tires are a little more available than 13", probably due to Alfa's using them.
I will try to buy extra tires just in case they really are on the verge of disappearing.
I do intend to drive the car hard, Virginia City Hill Climb and Silver State Challenge.
Hope I will never be forced to go up to 15" or larger, just plain hate the look of oversize wheels with too little rubber on a street car.

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I plan on using the 15" wheels that are on my 89 mustang parts car with 225-50r15 tire to get as close to a 24" wheel as possible. No rhyme or reason other than my car must be able to be serviced on the side of a nap and or tire shop same day.

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-STu

There is no shame in defeat, so long as the spirit is unconquered

My Build Log

What was probably years ago I posed the same question. If memory serves, I posted my question after I spent a weekend at a vintage car race and saw the small stuff on some of those cars. I think I posed my question in terms of unsprung weight -- tires, rims, brakes, etc. And I bet we agree -- like Caterham said, we don't need the monster brakes, etc on our cars.

So yeah, in theory, 13" would be great just to keep the weight down.

But, as I recall, it came down to tire availability. I posted my question about the time when Goodyear started slashing its lineup of performance / competition tire sizes. There are probably competitive race tires for 13" applications, but getting a good "performance" 13" tire for the road is a different story. BTW, in the 80's, I had 13" Goodyear Gatorbacks on my 84 turbo Colt....

I'm told that the The Tyrrell P34 (6-wheeled F1 car) was abandoned in large part due to tire availability.

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Geek49203 aka
Tim Wohlford
Louisville, KY
Hayes front, S10 +2 rear, Lalo body.

For comp usage, it's hard to beat 13" tire selection in sizes that fit the cars.
For street usage, 15's are the ticket as there are many sizes that work for the car and are readily available as well as a huge selection of wheels anywhere from 15x6 to 15x9 and select applications that go all the way to 15x11.
They are lighter and cheaper than 16"-up, hard to argue with that...

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Moti

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