georgealready

Using my super fancy home-made bump steer gauge, I measured the rear bump steer with stock suspension on my 2005.

I found only .005" under compression and .007" under decompression from stock.

Can anybody either invalidate my methodology (shown in the picture) or confirm that AP2 cars have almost no rear bump steer from the factory?

Thanks for the help.

Sebring AP1

At stock height you are correct.

macr88

How did you maintain the distance of the board with the dial indicator? The arm doesn't move up and down without moving in and out right?

georgealready

There's a bolt with a rounded end on the other side, so the constant is the front of the hub. The dial indicator is reflecting change at the back of the hub.

Good to know that there's no bump steer I guess.

Thanks for the replies.

robrob

Quote:

The dial indicator is reflecting change at the back of the hub.

It needs to be measured at the back of the tire to compare it to Honda's toe numbers in inches.

You also have to multiply that 0.05 by 4 to get total rear toe-in (leading & trailing edge of both tires--I realize that in a corner the outside tire is supplying more traction than the inside tire though).

Those small toe-in numbers can be deceiving. Using a rough hub to tire tire distance correction of about 30% the total rear toe-in change comes to 0.026 inch or 0.06 degrees. With AP2 rear toe spec'd at 0.14" you're getting about an 18.5% change of toe-in at full compression. Still not huge, but more than most would think.

Were you getting toe-in during compression and extension, or toe-in one way and toe-out the other? Did the toe curve appear to be linear or curved? (curved=most of toe change occurs near full extension or retraction)

One thing about your methodology though, it appears that wheel (and hub) camber would affect the readings. Imagine what 45 degrees of negative camber would do to your needle movement.