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E. Tyler Pedersen

What Tire Size Does Your Team Run?

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On the Supra, anything near 255/40R17. Will go up or down a little in width or aspect to save a few $$ if there's a good sale.

 

For the other vehicles we're considering as future Champcars, 245/40R15, or anything between a 165/70R10 and 175/50R13.

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16 hours ago, Team Infiniti said:

Why?

 

Just to see.  We started with the 245s but I never did any side-by-side testing.  My thoughts are: slightly lower gearing, little lower cg, less weight (?), a little more sidewall stretch/stiffness on the 9 (or 9.5), getting the tire in a more optimum heat range.

 

One thing we've always enjoyed is extremely good tire wear.  Like 2-3 events on a set.  One set I even had to life based on heat cycles.  Not that I mind, but Its made me a little concerned that we're running a little too much tire for our power/weight and not getting the tire in its optimum temp/grip range.  Again, just figured I'd test and see.  Of course, I need a running/driving car before any of that can happen :blink:

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Are these responses considering the new fender rules? I just remembered to check to see if the 225's would fit. Looks like I won't have enough points on the CRX to add flares. So I would have to cut off the Quarter panels and throw them in the english wheel to get the width. 

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2 minutes ago, SpeedMaverick said:

Are these responses considering the new fender rules? I just remembered to check to see if the 225's would fit. Looks like I won't have enough points on the CRX to add flares. So I would have to cut off the Quarter panels and throw them in the english wheel to get the width. 

You don't have 3 extra points?

 

Ditch that 10 point front strut brace, it doesn't do much anyway.

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No front brace. I will have the 2 forward cage struts so no need for one. CRX has adjustable coilovers and an engine swap. That is 450. Suspension adjustment and a couple other items takes me to about 520 If I can substitute something for the 4 rod ends for rear toe and still be adjustable then I will be at 500.  Still looking at bending the spindles an slotting the upper mounts for no points. Aero is key on the CRX for HP tracks. So big tires will hurt that.The Civic won't use up the 300 points so it will be more likely to need the extra tire. That will be part of the testing. What gives me more. The tires or shocks. I know 3rd Gear Pulls said the shocks weren't worth the points. 75 per corner seems a bit high. Are they 3 times more effective than a turbo? I don't think so. But I will accept what is in the rules right now. I think that 25-50 per corner is more realistic.  My Prelude has the adjustable shocks and I was told By the last owner that they were worth it on that car which has no power and plenty of fuel. When I got the car home I discovered it had 2" front toe out and 1.25" rear toe out. All in the right rear. Maybe it will be faster if all the wheels point the same direction. I am considering a turbo on the Civic. Fuel can be conserved to some degree. But having HP on tap could come in handy. 7 hour races on Sunday could put us up front when it counts.

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Tires are 2/3 of your suspension. Big tires don't add drag on the straights unless they aren't covered and are sticking out. You'll gain more in the corners than you lose on the straights.

 

Use the stock toe links on the rear and slot holes if you need to. Same with camber. Lower the car first though, you may find that you're already close enough.  

 

CRX swap starts at 200 points and adds at least 50 pts, then you have to add 300 pts for your adjustable shocks = 550 with nothing else. Lose the 300 pt shocks; wider tires and 3 points worth of flares will be faster because if nothing else you have 297 pts for other mods.  We have Koni Str.ts and they work well enough with the 225/45/15s that I'm considering 245/40/15s for next time. 

 

But before you take them off, see if you can play with them a bit to see what the car likes. If you find a trend you can at least try to find a set of non-adjustables that are close to the best setting. 

 

Edited by mender

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225 45 R 15 on both E30's. We might do flares and new wheels this year on one car to go up to 245s on a 15 inch. 225's 45 R 15's are not available in the Maxxis line. 

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