Big tires (Page 3/5)
hunter29 JUL 29, 09:05 PM

quote
Originally posted by williegoat:

There are three major things that will have an effect on acceleration and breaking:

1) weight has already been discussed.
2) tire compound is obvious.
3) overall diameter: if you choose a combination with a diameter close to the original tires, there will be little noticeable change. So, if you go with a lower (numerically) aspect ratio, you will want a bigger wheel. Overall diameter much bigger or smaller will effect gearing or leverage.

If you look at my combination:

front: 17x7" with 225/45ZR17
rear: 18x8" with 245/40ZR18

The front and rear have nearly the same overall diameter.



Right, I have noticed that each tire is different in diameter from oem to oem. Even in the same size..

I'm trying to keep it at 25 inches however I'm having trouble finding out what factory tires were for my car, if only I could look them up..
My main motivation to do this is to get better tire choices.

[This message has been edited by hunter29 (edited 07-30-2024).]

williegoat JUL 29, 09:32 PM

quote
Originally posted by hunter29:

Right, I have noticed that each tire is different in diameter from oem to oem. Even in the same size..

I'm trying to keep it at 25 inches however I'm having trouble finding out what factory tires were.

My main motivation to do this is to get better tire choices.


Well, this is the best place to ask. Someone will know the answer.
hunter29 JUL 30, 11:55 AM

quote
Originally posted by williegoat:

Well, this is the best place to ask. Someone will know the answer.



I wrote Goodyear, you never know...
olejoedad JUL 30, 12:33 PM
I'm running 17x7 on all four corners, 215-50-17 front and 235-50-17 rear.
hunter29 JUL 30, 01:41 PM

quote
Originally posted by olejoedad:

I'm running 17x7 on all four corners, 215-50-17 front and 235-50-17 rear.




And I have to ask is your car lowered ?
fieroguru JUL 30, 06:57 PM

quote
Originally posted by hunter29:
Right, I have noticed that each tire is different in diameter from oem to oem. Even in the same size..



They don't change than much, maybe 0.1" overall.
195/70/14 = 24.7"
215-60/14 = 24.2"
205/60/15 = 24.7"
215/60/15 = 25.2"

This is my setup:
235/40/17 (24.4") in front and 285/30/18 (24.7") in the rear. It is lowered about 1 to 1.5 inches with 3x the power of a 2.8 (when it was naturally aspirated, it is even more now with the turbo)

[This message has been edited by fieroguru (edited 07-30-2024).]

hyperv6 JUL 30, 07:13 PM
Here is the trouble when going big for acceleration.

#1 if you go larger diameter it changes the gear ratio. It will damage acceleration unless you change the ratio.

#2 braking with larger diameter wheels will suffer as you have more torque on the brakes . To fix this you should go larger on brakes. Not justvroyors but pad size. Many 4x4 truck end up hitting cars as their braking distance increases.
hyperv6 JUL 30, 07:15 PM

quote
Originally posted by hunter29:

Right, I have noticed that each tire is different in diameter from oem to oem. Even in the same size..

I'm trying to keep it at 25 inches however I'm having trouble finding out what factory tires were for my car, if only I could look them up..
My main motivation to do this is to get better tire choices.




Go to tire rack and they show specs for tires

Also yes they vary a bit as they round them off measurement wise.
hunter29 JUL 31, 07:14 AM

quote
Originally posted by hyperv6:


Go to tire rack and they show specs for tires

Also yes they vary a bit as they round them off measurement wise.



All good info guys,thanks..


Tire Rack will not allow searching tires or wheels by size, so I won't be doing business with them.
hunter29 JUL 31, 10:33 AM
I measured my factory tires, front 24 1/2 rear 24 3/4 .. sounds about right I think...