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heys guys i have a 97 camaro rs and i was going to buy some black Z-06 rims but i dont know what size to buy that would fit my car perfectly. I was wanting to get some 18*9 1/2s. Ur help would be greatly apprecciated.
 

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Re: wheel measurments... good info

I found this note on the site www.1010tires.com/TireSizeCalculator.asp

"When changing tire sizes, we recommend staying within 3% of the diameter of the original tire. Any more than this and you face the risk of brake failure."

Does anyone understand this note on possible brake failure?
 

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Re: wheel measurments... good info

Dave H. said:
I found this note on the site www.1010tires.com/TireSizeCalculator.asp

"When changing tire sizes, we recommend staying within 3% of the diameter of the original tire. Any more than this and you face the risk of brake failure."

Does anyone understand this note on possible brake failure?
It's more an issues with MAJOR upsizing on SUV's. That are putting on 20's-22's, or 4x4's going to 40" tires or more. The rolling mass of the wheel/tire combo becomes too heavy for the stock brakes. Problems like brake fade, warping rotors, extremely long braking distances. If you have stock discs, or you've upgraded to big brakes, then it's not really an issue.
 

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Re: wheel measurments... good info

Actually it's something to consider anytime you plus size wheels and tires. It's all about leverage, remember the bicycle wheel example from school days? The area closest to the hub moves slower than the area out by the rim. I'm not going to do the math but a mark on the rim has to travel a lot farther than a mark by the axle flange travels, they both only make one revolution and start and stop at the same time.

It takes more braking power to stop the taller wheel and plus sizing can put you in a position where your existing brakes are not enough. Weight can come into play as well and taller wheels can often mean more unsprung (not carried by the cars suspension) weight. In acceleration loosing 10lbs of unsprung weight is equal to 100lbs of sprung weight. It works the same for braking, 10 lbs extra in wheels and tires is like throwing 100lbs in the trunk.

For the website though, it's a disclaimer so if you put 20's on your car and have brake issues they are off the hook. 3% on a factory 26" - 31" tall tire is less than a 1" increase. Using my Colorado as an example it has 31" tall tires from the factory but another option package includes 28" tall tires and there is even a 26" or 27" tall tire option. The vehicle's brakes are fine with the 32" tall tires I installed.

Take a stock drum brake 1st gen that came with tires in the 25" - 26" tall range and put 28" tall tires all around and you will run into braking issues... Remember though you could run 20" wheels on it if the tires only had 3" sidewalls as the overall height ends up being 26"...
 

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Re: wheel measurments... good info

thanks dennis
this is some really good info
69z28 rs x33
 

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Re: wheel measurments... good info

This sin't just about the extra weight of upsizing wheels/tires. More importantly on cars with ABS brake systems, this can cause failure of this system, do to the fact that it is computer programmed to run off your stock tire height. And of course it messes with the vehicles computer as far as trip computer, odometer, gearing, traction contol and can also lead to transmission failures.
Hope that answers some of your questions.



Dave H. said:
I found this note on the site www.1010tires.com/TireSizeCalculator.asp

"When changing tire sizes, we recommend staying within 3% of the diameter of the original tire. Any more than this and you face the risk of brake failure."

Does anyone understand this note on possible brake failure?
 

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Re: wheel measurments... good info

Thanks Kev. I'm going to try to consolidate all the useful wheel and tire information out there and create a page just for folks to read in this section pretty soon since I'm the new mod on this one. Appreciate any more useful links you or anyone else might have. Thank you again - Christropher
 

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Re: wheel measurments... good info

I am trying to put 17 or 18" wheels on my 68 Camaro. I go down to my local tire shop and they really can't help me with rim and tire sizing. They just say we can try on different sizes. I would like to prevent that step. Deos anybody know a rim sizing IE: Back spacing witch would center the laod for the bearings but yet still fill the rear wheel well and front. Would be satified for 17 both rear and front or 17 front, 18 rear. Pretty open would just like to drop it about 2" with the Hotchkis TVS. Thanks
 

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Re: wheel measurments... good info

I Was Watching An Episode Of Monster Garage With Jesse James And They Wwere Putting On Bigger Tires And Rims On A Car. He Explained It As Big Rims Big Lever. If You Dont Upgrade Your Brakes It Puts More Stress On The Rotors And Brake Calipers.. Just A Thought
 

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Re: wheel measurments... good info

Chevyboy, you are polluting our forum... again.

The overall diameter of the tire can't change much, 25 - 26 1/2" tall is pretty much it, and I like even shorter in front.
If you replace a 215-70-15 tire that's 26" tall with a 255-45-17" tire that's 25 1/2" tall, tll me about your lever effect?

RIM diameter is a non issue, it just don't matter.
8" rim needs 4 1/2" backspace
9 1/2" rim need 5 1/2"
7" rim needs 4"
"comfort level" is 225 in front, 255 in back. "better measure twice" = 245 in front, 275 in back.
 
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