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13" wheels?

Old 02-13-13, 01:48 AM
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13" wheels?

I notice a lot of older racers running 13" wheels. I'm considering my options right now because I'm might not have the budget to upgrade my rear drum brake this season. My thoughts are that it would take less braking power to slow down a small light race wheel . Though I feel maybe a loss in carried momentum when off the throttle. Any thought Pros cons etc??
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Old 02-13-13, 08:40 PM
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Depending on what tires you have available I would go with the smallest rim that will fit over your brakes. No need to spin 4 larger flywheels up to speed every time you accelerate and you'll have lower unsprung weight.
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Old 02-14-13, 05:29 PM
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Originally Posted by jgrewe View Post
Depending on what tires you have available I would go with the smallest rim that will fit over your brakes. No need to spin 4 larger flywheels up to speed every time you accelerate and you'll have lower unsprung weight.
This is what I'm thinking so I'm gonna go with the 13's
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Old 02-14-13, 05:44 PM
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A lot of guys run 13s. On an SCCA HP racecar we've been campaigning (not an RX-7), we've run both 13s and 15s. We've found that there is a tendency to lock up the 13s during braking more than the 15s. This could be due to slightly less contact patch, but more than likely it's a side effect of there being less rotational mass while the brakes offer the same clamping force. If you run 13s, be careful when you initially get on the brakes, choose a brake pad with very light initial bite, or look into a brake proportioning valve.
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Old 02-16-13, 12:02 AM
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Originally Posted by Prof. Chaos View Post
A lot of guys run 13s. On an SCCA HP racecar we've been campaigning (not an RX-7), we've run both 13s and 15s. We've found that there is a tendency to lock up the 13s during braking more than the 15s. This could be due to slightly less contact patch, but more than likely it's a side effect of there being less rotational mass while the brakes offer the same clamping force. If you run 13s, be careful when you initially get on the brakes, choose a brake pad with very light initial bite, or look into a brake proportioning valve.
So if I go with these super light 13" wheels Could I possibly run with the GS Drum brake the car came with? Also what about tires is that an issue someone was telling me they're hard to find good race tires in 13's
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Old 02-16-13, 12:22 AM
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not really sure what you're racing... but you can get a few Hooiser A6s in 13's.

255s and 225s.

I ran a reverse stagger for a while on my corolla and they worked really well.

running 13s (with short sidewall tires) also lowers the car another inch or so with little to no bad side effects...
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Old 02-21-13, 11:44 AM
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Originally Posted by Adam12A View Post
So if I go with these super light 13" wheels Could I possibly run with the GS Drum brake the car came with? Also what about tires is that an issue someone was telling me they're hard to find good race tires in 13's
As mentioned, there are 13" R-compounds like the Hoosier A6, and Hoosier also makes 13" slicks, both bias-ply and radial.

I have no experience with RX-7 drum brakes, but I do know on the HP racecar I mentioned earlier that we've been running rear drums for years (with both 15s and 13s) and the car runs great. In fact, we're running stock brake shoes, too. The rear brakes don't really do enough to concern yourself about. Just make sure you have a good front brake setup (ie: quality race pads and good brake ducting).
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Old 02-24-13, 08:04 PM
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You still haven't told us what type of racing your doing. But like everyone else said. The is alot of 13" tires to chose from.
I'm running them on my PTE car. 225 45 13
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Old 02-25-13, 12:03 PM
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Originally Posted by Gian View Post
You still haven't told us what type of racing your doing. But like everyone else said. The is alot of 13" tires to chose from.
I'm running them on my PTE car. 225 45 13
ISCCA or possibly NASA road racing.
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