Bump steer question

brian6pac said

Sorry if I did not specify the exact set up. I have modified steering arms, pinto rack out front, other than that it is stock. I have 3/4" bolts in the upper bumper to stop the drop so the car doesn't lift all the way through the travel but it only stops about 1" of drop. It has most of the travel and it has 0 toe change all the way.

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My guess is you did 2 things
1) mimicked the arc of the LCA with your the tie rod assembly which is good, but IMO, only part of the puzzle.
2) limited travel to minimize the bump steer thru normal (not limited) travel and with its limited suspension travel, you also eliminate / minimize the effects of camber change on the toe.....another piece of the puzzle.

Your set up sounds similar to the way the early 70 Pro Stocks w/ racks set up their race fronts....limited the travel to achieve minimum bump steer. Joe Pappas, who crewed on the 72-73 Mopar Missile Duster, told me they literally ran on the stops....about 1" of travel that was due to the deflection of the (then) rubber (shortened) stops. With rear steer spindles and steering arms swapped / modified, Ackerman sucked, but they were more concerned with straight line performance. They would spend a whole day on the front end addressing bump steer constantly making sure the wheels stayed as straight as possible.

Butch Leal told me he and Ron Butler would also spend a day to achieve very minimal (never zero) bump steer with their only way to keep the bump steer number low was to limit suspension travel to around 2" total.....they had to have some travel, Butch always had the nose in the air.

I just like to add to the discussion. If what you do works for you....I'm good with it.