tire diameter differences front/rear and active handling
Thread Starter
Safety Car
Joined: Feb 2000
Posts: 3,683
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From: Austria
tire diameter differences front/rear and active handling
If the difference in tire diameter between fronts and rear tires
changes 1,42%, compared to the stock setup, will it effect the active handling or even make it stop working?
Or is that difference to small to effect the AH computer at all?
This is the stock tire infos fronts and rears:
Overall height front 25,68....rear 26,66
Circumference front 80,68....rear 83,76
This is the new tires infos fronts and rears:
Overall height front 25,50....rear 26,85
Circumference front 80,10....rear 84,34
I don´t care about the traction control ....just the AH.
Thanks!
changes 1,42%, compared to the stock setup, will it effect the active handling or even make it stop working?
Or is that difference to small to effect the AH computer at all?
This is the stock tire infos fronts and rears:
Overall height front 25,68....rear 26,66
Circumference front 80,68....rear 83,76
This is the new tires infos fronts and rears:
Overall height front 25,50....rear 26,85
Circumference front 80,10....rear 84,34
I don´t care about the traction control ....just the AH.
Thanks!
Last edited by Austrian Vette; Oct 18, 2008 at 11:02 AM.
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
The stock tires have about 1 inch difference (as you have shown). It is generally accepted that you need at least 0.5 inches difference for AH and Traction Control to work properly.
You have it and should be okay. Now, maybe because you have MORE difference, both AH and TC may come on later.
What does ASR stand for?
ABS (brakes) look at the rotational speed of the wheel/tire and pulse the brakes when locking (no rotation) is sensed. So, tire size has no affect on this system. However larger diameter tires require more braking force.
You have it and should be okay. Now, maybe because you have MORE difference, both AH and TC may come on later.
What does ASR stand for?
ABS (brakes) look at the rotational speed of the wheel/tire and pulse the brakes when locking (no rotation) is sensed. So, tire size has no affect on this system. However larger diameter tires require more braking force.
Last edited by Oldvetter; Oct 18, 2008 at 10:10 AM.
Thread Starter
Safety Car
Joined: Feb 2000
Posts: 3,683
Likes: 0
From: Austria
The stock tires have about 1 inch difference (as you have shown). It is generally accepted that you need at least 0.5 inches difference for AH and Traction Control to work properly.
You have it and should be okay. Now, maybe because you have MORE difference, both AH and TC may come on later.
What does ASR stand for?
ABS (brakes) look at the rotational speed of the wheel/tire and pulse the brakes when locking (no rotation) is sensed. So, tire size has no affect on this system. However larger diameter tires require more braking force.
You have it and should be okay. Now, maybe because you have MORE difference, both AH and TC may come on later.
What does ASR stand for?
ABS (brakes) look at the rotational speed of the wheel/tire and pulse the brakes when locking (no rotation) is sensed. So, tire size has no affect on this system. However larger diameter tires require more braking force.
ASR stands for traction control here in Austria....I just changed that to traction control in my firs post, so noone is confused....
Anyone knows, if the AH really comes on later....and most important:
will it still be able to save my ***...just in case
...or will it step in too late, then, to be able to correct anything?
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
Now that I think about it, AH should not be affected. AH depends on the attitude of the car verses the angle of the steering wheel. It calculates where you are going verses where you are trying to go and selectively applies individual brakes to correct.
Now TC may come on later as it calulates when the rear tires are spinning by comparing rpms of the front tires verses the rear.
Your 1999 C5s use the earlier version of AH and TC, the TC was more "intrusive" than later versions. I don't think "it coming on later" will be much of a problem.
I have a friend that races his Dodge Viper, he always talks about the C5's AH saving them from spinning out. His Viper has no AH.
Now TC may come on later as it calulates when the rear tires are spinning by comparing rpms of the front tires verses the rear.
Your 1999 C5s use the earlier version of AH and TC, the TC was more "intrusive" than later versions. I don't think "it coming on later" will be much of a problem.
I have a friend that races his Dodge Viper, he always talks about the C5's AH saving them from spinning out. His Viper has no AH.
Last edited by Oldvetter; Oct 18, 2008 at 12:14 PM.
Thread Starter
Safety Car
Joined: Feb 2000
Posts: 3,683
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From: Austria
Now that I think about it, AH should not be affected. AH depends on the attitude of the car verses the angle of the steering wheel. It calculates where you are going verses where you are trying to go and selectively applies individual brakes to correct.
Now TC may come on later as it calulates when the rear tires are spinning by comparing rpms of the front tires verses the rear.
Your 1999 C5s use the earlier version of AH and TC, the TC was more "intrusive" than later versions. I don't think "it coming on later" will be much of a problem.
I have a friend that races his Dodge Viper, he always talks about the C5's AH saving them from spinning out. His Viper has no AH.
Now TC may come on later as it calulates when the rear tires are spinning by comparing rpms of the front tires verses the rear.
Your 1999 C5s use the earlier version of AH and TC, the TC was more "intrusive" than later versions. I don't think "it coming on later" will be much of a problem.
I have a friend that races his Dodge Viper, he always talks about the C5's AH saving them from spinning out. His Viper has no AH.
Yes, I think you are right with the AH.
BTW, I have both....C5 and Viper......so I know what your friend is talking about
But I don´t race my Viper at the round course.....I only race the Vette.
And having the AH active on wet tracks is a cheap insurance, when you try hard to better your times and keep driving on the limit (or above
) 
Safety Car
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From: Indianapolis Indiana
Cruise-In III Veteran
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I can say from experience AH is not affected by a tire size issue. I've run 305/35/18f and 335/30/18r tires at HPDE's with AH on and while it may freak out TC, the AH works fine.
Tech Contributor
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From: Charlotte, NC (formerly Endicott, NY)
Thread Starter
Safety Car
Joined: Feb 2000
Posts: 3,683
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From: Austria
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