Corvette Forum : Corvette Forums banner
1 - 3 of 3 Posts

746 Posts
Discussion Starter · #1 ·
Guys check your own bump steer.
The proper way to check bump steer is with a plate on the wheel instead of a tire and rim, no spring and a pair of dial gages on both ends of the aluminum plate.
That is expensive and labor intensive.
Do a check in your driveway. It is rough but gets you the idea.
Laying under the front bumper on the drivers side/ passengers if if you prefer, reach across with a good tape, hook it in the tread and the spot where you hook it must remain the same each time measure across to another spot on the tire you are laying infront of.
Mark this dimension down. This should be taken as high up as possible, you are trying to get roughly in the center of the tire in height, or hub height.
This is just a number but you call it toe.
With a jack under the center of the car jack the car up exactly 1 inch. Measure the same points as last time. This is your new toe at 1 inch rise. Remember if you cheat on the meauring points by changing them you are causing inacurracies.
Raise the car 2 inches and do it agian.
Raise it 3 inches a do again.
The toe reading will be getting less as the car toes in. Subtract the values and right them down.
You will see for 1 inch rise your toe in might be 1/8th to 1/4, 2 inch rise might be 3/8 or more and 3 inches even alot more.
This is not true toe in because the back of the tire toes out the same amount.
So the toe is actually double what you are reading. So if your reading is 1/4 inc h toe in double it and you have 1/2 inch toe in.
You can not pull the car down. I have the special tools to do it.
When I started my 75 the toe in was an honest 2 plus inches.
I am down to 5/16 toe in total and .015 for 2 inches of toe down.
Believe me it make all the difference in the world with high speed driving down a rough road or over the crest of hills.
I almost became a fatality at 100 mph over a bridge when the car went right nuts.
Not today with the better reworked front end. That same bridge at 100 mph doesn't even warrant a twitch.
Good luck and I have lots of articles on this subject.
Little was known about it 20 years ago but to day all race cars have the bump steer removed.
They recommend .010 max and .050 would put a nascar in the wall.
We measure ours by the inch.

746 Posts
Discussion Starter · #3 ·
MGA the aluminum plate is just that a plate with holes drilled for the hub and 5 lug nuts, It just alllows a dial indicator to run up and down it tracking toe changes.
At our stage we don't have a bump steer gage, well I do but you don't need it.
I am too cheap to buy a digital camera and have to make do with borrowing one occasionally.
I know what I am going to buy the wife this christmas.:laughing: :laughing:
1 - 3 of 3 Posts