Directional stability vs wide tires
Thread Starter
Advanced
Joined: Feb 2001
Posts: 71
Likes: 0
Directional stability vs wide tires
Hi,
I have 275-40-17's Kumo's on 17 x 9.5" wheels, 4.5" backset on all 4 corners with no modification to fenders/hubs etc. on an 81 corvette. The car looks sweet but if the road is no perfect, the thing wants to dart all over the lane. Thought it was just the corvete but when I put the wheels on my Camaro, it does the same thing.
The thing that I do not understand, I ran a 265-50-15 on a 15 x 8 wheel, 4" back set. Same cross section, same tread width, both pretty much centered on the hub but it does not dart around.
Whats UP?
Would changing the caster help? Run the same width wheel but go to a 5" back set? Like to keep the current set up but it is no longer fun to drive.
Any ideas appreciated,
Bronco_Rider
I have 275-40-17's Kumo's on 17 x 9.5" wheels, 4.5" backset on all 4 corners with no modification to fenders/hubs etc. on an 81 corvette. The car looks sweet but if the road is no perfect, the thing wants to dart all over the lane. Thought it was just the corvete but when I put the wheels on my Camaro, it does the same thing.
The thing that I do not understand, I ran a 265-50-15 on a 15 x 8 wheel, 4" back set. Same cross section, same tread width, both pretty much centered on the hub but it does not dart around.
Whats UP?
Would changing the caster help? Run the same width wheel but go to a 5" back set? Like to keep the current set up but it is no longer fun to drive.
Any ideas appreciated,
Bronco_Rider
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
Re: Directional stability vs wide tires (Bronco Rider)
What are your alignment specs? I'm running 255/50-17 on 17x8 rims and the car is stable at all speeds.
My alignment is:
Front camber: -0.3
Front Caster: +4.0
Toe in: 1/8
Rear Camber: -0.5
Rear Toe-in: 1/8
My alignment is:
Front camber: -0.3
Front Caster: +4.0
Toe in: 1/8
Rear Camber: -0.5
Rear Toe-in: 1/8
Team Owner
Joined: Sep 2003
Posts: 88,393
Likes: 2
From: eville in
Re: Directional stability vs wide tires (Bronco Rider)
stiffer sidewall , different tread, different rubber compound, have you played with tire pressure's any, bet it turns in quickor into a turn :thumbs:
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Re: Directional stability vs wide tires (comp)
Have you ever wondered why those big 4X4 pickups with monster tires install those steering arm shock absorbers?
Well your just experiencing why they have them.
Additional castor, new ball joints and A-arm bushings.......... Will all help, but life is all a comprimises :yesnod:
Well your just experiencing why they have them.
Additional castor, new ball joints and A-arm bushings.......... Will all help, but life is all a comprimises :yesnod:
Thread Starter
Advanced
Joined: Feb 2001
Posts: 71
Likes: 0
Re: Directional stability vs wide tires (zwede)
Hi,
What are you running for back set on the 17 x 8 wheels? 4"?
I have run the car auro cross and it corners much better that stock. It could be the alignment is still set up for auto cross.
My 4 wheel drive doesn't wander as bad as the Corvette
Thanks for the responses
Bronco_Rider
What are you running for back set on the 17 x 8 wheels? 4"?
I have run the car auro cross and it corners much better that stock. It could be the alignment is still set up for auto cross.
My 4 wheel drive doesn't wander as bad as the Corvette
Thanks for the responses
Bronco_Rider
Pro
Joined: Jun 2001
Posts: 672
Likes: 0
From: Quebec
Re: Directional stability vs wide tires (zwede)
I have the same problem and I run 255/45 ZR17 Khumo Ecsta Supra. I have to say that it was unstable with the 255/60 R15 Goodyear GTII too until I run the specified tire pressure for the Corvette 1980: 26 psi all-around. I'll try to run my 17" with 26 psi next summer.
Zwede:
How did you get 4.0 degree of caster? Tubular A-Arm?
Stephan
[Modified by American Boy, 6:27 PM 1/7/2004]
Zwede:
How did you get 4.0 degree of caster? Tubular A-Arm?
Stephan
[Modified by American Boy, 6:27 PM 1/7/2004]
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