Tire Ratios = problem ?
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Registered User
Joined: Mar 2004
Posts: 283
From: Fort Lauderdale
Rep Power: 35
Tire Ratios = problem ?
Having some serious issues and hoping I am not screwed ....
Help !!!!!
Just installed a set of 20" Champion wheels with Nitto Invo's ..
245/30/20 front
305/25/20 rear
Also installed GMG springs ....
The car is dangerously unstable at speed ....
Mechanic thinks either the springs were installed wrong by previous wrench or the tire ratios are off ...
Just digging into this on the forums - but any help would be greatly appreciated ..
Thanks !!!!
Help !!!!!
Just installed a set of 20" Champion wheels with Nitto Invo's ..
245/30/20 front
305/25/20 rear
Also installed GMG springs ....
The car is dangerously unstable at speed ....
Mechanic thinks either the springs were installed wrong by previous wrench or the tire ratios are off ...
Just digging into this on the forums - but any help would be greatly appreciated ..
Thanks !!!!
Last edited by TripleNet; Oct 26, 2015 at 04:57 PM.
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Joined: Oct 2012
Posts: 447
From: Orange County
Rep Power: 137
Factory size is:
Front: 235/35-19
Rear: 305/30-19
With your current setup, you have a circumference difference (stock vs. new) of:
Front: -4.4"
Rear: +0.97"
So, you're current setup is a very different diameter compared to stock! This is pretty unhealthy for your differentials. Stock, the front circumference is ~80" and rear is 82". So, you can see that you are exceeding a 5% variance on the front...not much on the back.
You should be able to easily visually inspect the springs to see if they installed correctly or not.
Source: http://www.discounttiredirect.com/di...nfoTireMath.do
Front: 235/35-19
Rear: 305/30-19
With your current setup, you have a circumference difference (stock vs. new) of:
Front: -4.4"
Rear: +0.97"
So, you're current setup is a very different diameter compared to stock! This is pretty unhealthy for your differentials. Stock, the front circumference is ~80" and rear is 82". So, you can see that you are exceeding a 5% variance on the front...not much on the back.
You should be able to easily visually inspect the springs to see if they installed correctly or not.
Source: http://www.discounttiredirect.com/di...nfoTireMath.do
Last edited by TypeRx; Oct 26, 2015 at 05:13 PM.
Thread Starter
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Registered User
Joined: Mar 2004
Posts: 283
From: Fort Lauderdale
Rep Power: 35
Factory size is:
Front: 235/35-19
Rear: 305/30-19
With your current setup, you have a circumference difference (stock vs. new) of:
Front: -4.4"
Rear: +0.97"
So, you're current setup is a very different diameter compared to stock! This is pretty unhealthy for your differentials. Stock, the front circumference is ~80" and rear is 82". So, you can see that you are exceeding a 5% variance on the front...not much on the back.
You should be able to easily visually inspect the springs to see if they installed correctly or not.
Source: http://www.discounttiredirect.com/di...nfoTireMath.do
Front: 235/35-19
Rear: 305/30-19
With your current setup, you have a circumference difference (stock vs. new) of:
Front: -4.4"
Rear: +0.97"
So, you're current setup is a very different diameter compared to stock! This is pretty unhealthy for your differentials. Stock, the front circumference is ~80" and rear is 82". So, you can see that you are exceeding a 5% variance on the front...not much on the back.
You should be able to easily visually inspect the springs to see if they installed correctly or not.
Source: http://www.discounttiredirect.com/di...nfoTireMath.do
I am a novice here so forgive me for the questions if they make no sense
Much appreciated
Registered User
Joined: May 2013
Posts: 664
From: Texas
Rep Power: 83
agree with comment above -
if you are going to run a 245/30/20 you should run a 325/25/20 in the rear
You are playing dangerous game of roulette with your differential with those mismatched sizes.
if you are going to run a 245/30/20 you should run a 325/25/20 in the rear
You are playing dangerous game of roulette with your differential with those mismatched sizes.
Thread Starter
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Registered User
Joined: Mar 2004
Posts: 283
From: Fort Lauderdale
Rep Power: 35
Luckily I only put on around 40 miles on the car ... Not driving it again until I get the stock wheels back on
Last edited by TripleNet; Oct 26, 2015 at 05:57 PM.
Registered User
Joined: Feb 2010
Posts: 1,330
From: Pleasantville!
Rep Power: 167
Either way, get those tire ratios corrected so you do no blow up yoru all wheel drive differential.
Good luck!
DC
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