Driving Characteristics After Changes

[Track Junky]

Most you guys know that recently I have made a few changes on my car. I have been going back and forth with Blake on this but I decided to start a thread to see if anyone else has similar feeling in the driveability of your cars.

My car ran 17x9.5 torque thrusts with 275 R888's all around. Car drove great and was very predictable.

I added 17x9.5 and 18x10.5 vette wheels. 275's up front with 2" hubcentric spacer, 315's out back with 1 1/2"" hubcentric spacer. I also installed a Fays 2 watts link.

Now when I jump on the throttle from a 30 mph roll the car dips in the passenger side rear and veers to the left.

Anybody else getting this with larger 100 tread wear tires in the rear?

[Mean 69]

You made two changes simultaneously, so why do you think that the tires are the issue, and not the addition of the Watt's?

[70rs]

I'm only taking a shot in the dark here, but did ANY rear geometry change with the addition of the watts link? Was the rear centered before the tire swap?
Maybe there was already some kind of issue that the watts link or wider tires is magnifying?
All else being equal, a tire change alone shouldn't CAUSE a problem should it?

[Track Junky]

Originally Posted by Mean 69

You made two changes simultaneously, so why do you think that the tires are the issue, and not the addition of the Watt's?

I'm not discounting the watts. I would like to know if anybody else's car has similar characteristics though.

Originally Posted by 70rs

I'm only taking a shot in the dark here, but did ANY rear geometry change with the addition of the watts link? Was the rear centered before the tire swap?
Maybe there was already some kind of issue that the watts link or wider tires is magnifying?
All else being equal, a tire change alone shouldn't CAUSE a problem should it?

Good point. Rear is centered but we did bring the top of the shocks inboard just outside the frame rails and the bottom of the shocks are still in stock location.

I dont think there was a previous problem and the car felt great before the changes aside from being a bit loose in the rear and the differential shifting from side to side in the corners hence the watts and wider tires.

[70rs]

A mystery.....
Heres a thought, if you have a GoPro camera, mount it under the rear of the body. Try to get as much suspension as you can in the cameras field of view. Take it for a spin, make it present the handling problem, review the footage and see whats moving around on you.
Are you running leaf springs? Maybe the mount point at the front of the spring or link on that side is loose or worn (bad bushings?)
It doesn't take much movement to cause a noticable diff in handlng.

[69sponge]

Try putting the TT2s back on to eliminate the diffrent rim and tire combo.

[Track Junky]

Originally Posted by 70rs

A mystery.....
Heres a thought, if you have a GoPro camera, mount it under the rear of the body. Try to get as much suspension as you can in the cameras field of view. Take it for a spin, make it present the handling problem, review the footage and see whats moving around on you.
Are you running leaf springs? Maybe the mount point at the front of the spring or link on that side is loose or worn (bad bushings?)
It doesn't take much movement to cause a noticable diff in handlng.

The camera thing is a good idea. I have a GoPro so I will see if I can make this happen. It does have Global West leaf springs.

Originally Posted by 69sponge

Try putting the TT2s back on to eliminate the diffrent rim and tire combo.

Good idea. I will probably try that after the adjustment phase has been exhausted.

Do you guy's think their might be an issue with my posi unit? It's been in for 9 years.

[70rs]

Wider tire getting better traction could be pulling it to one side, but I would think only if the differential and suspension were moving around. Double check all of your mounting oints and suspension bushings. Try the camera deal and see what comes up.
At least that way you don't go buying new parts guessing at whats wrong.

[wmhjr]

What tires are on the new combo? Are they also R888s?

I agree - put the TT2s and original rubber back on and test first. Do that BEFORE any other adjustments.

[Track Junky]

Originally Posted by wmhjr

What tires are on the new combo? Are they also R888s?

I agree - put the TT2s and original rubber back on and test first. Do that BEFORE any other adjustments.

Yeah, all R888's. Makes perfect sense. I've got a buddy coming up to help, hopefully he hasn't left his house yet and I can get him to pull his tires and wheels off of his car.