I changed from drums to disc brakes and 2in drop spindles. I had the car tubbed and put a 555 in it. I tested it today for the first time. when the tires was in the air they towed in a lot and once it hit the ground I really couldnt control it and jumped in the in the left lane real quick. any ideas what is wrong.When I put them on was on the lift and they towed in.when I put it on the ground they looked right. I had the alinement done , but that isnt any good in the air with the tires towing in alot.

Sounds like in the changes the bumpsteer was changed.

I have a little video but I can't seem to paste it on here. But soon as the car leaves you can see the tire shoot to the inside a bunch is that what you're referring to is Bump steer?

Bumpsteer.

Do a search for bumpsteer correction for a Nova. There are a few options but I’m not sure what is best fix.


Take the springs out and reassemble. Take a measurement at regular ride height and then again at full extension. Then one more at ride height going down the track. You will probably see three different measurements. You can limit travel and that will help but it’s a bandaid to the actual problem.

quote:

Originally posted by Novacaine:
I have a little video but I can't seem to paste it on here. But soon as the car leaves you can see the tire shoot to the inside a bunch is that what you're referring to is Bump steer?

Yes. Something in the geometry changed. It can be fixed by adjusting the angle of the tie rod by raising or lowering the attachment point to the steering knuckle. You can heat and bend the steering knuckle (time consuming) or modify the tie rod end to use spacers and possibly a heim joint instead of tie rod end.

It is very time consuming to make it right. There are compromises along the way. Each time the bump steer is changed the toe changes and vice/versa. Expect an iterative approach of trial and error. Try to pick a time to work on it where you have a weekend off. It's not something you're going to fix in a couple of hours.

Dave Morgan's book has good information on how to measure and how to fix, but expect some ingenuity on your end.

I can assure you the reward is worth the effort.

As mentioned above, the quick fix is get it close enough and limit travel.

I talked to the guy that set my car up. and he said to limit front end travel. measure front end height. then jack up 1 in and adjust the the threaded rod to touch and start from there. if the tires blow off go up 1/2 turn at a time till it works. that sound right? He said thats pretty common with drop spindles.

Limiting travel is a bandaid fix. Yes you may get it to somewhat work, but it’s best to correct the steering geometry like was already said. Btw, just my opinion but if your chassis guy always goes to limit travel to fix bumpsteer then you may want to find someone else to work with.

Everything was fine until I changed it to drop spindles and went to disc brakes of course. What if I change the drop spindles to the regular standard size spindles they came with the kit I just bought the drop spindles extra. If I would change back to this stock standard type spindle would that take care of my problem?

It will help but these cars have this issue naturally. You need to fix the issue, not bandaid it.

I have raced this car for 20 years and I've never had an issue till I change those drop spindles. I've never noticed I ever have a problem with it always drove and handle straight as an arrow. I've had the wheels up in the air 6 in to 3 ft and never had a problem.

The drop spindles can dramatically increase the amount of bumpsteer in a lot of cars.

One way to check this is to remove the front springs with it on a alignment rack and all hooked up. Take a baseline reading of toe-in at normal ride height and then raise and lower the front end 2 to 3 inches each way. With what you are saying, I would expect somewhere in the neighborhood of a half to three quarters inch difference between the raised and lowered readings.

You may never be able to take all of it out, which is normal, but you should be able to get it to less than a 10th of a inch change through the 4-6 inch range of travel.

Several companies make adjustable bumpsteer kits for these cars.

As was mentioned, if a so called chassis guy recommends limiting front end travel to put a band aid on bumpsteer, I'd be looking for a new chassis guy myself.

An alternative to spending a few hours on a alignment rack, is that the amount of bumpsteer there currently is in the car and how much adjustment is needed can all be modeled in a decent 2D CAD program but 3D is better.

Just went thur this with my car. Spindles i have have 4 sets of holes to mount the steering arms. They arms need to be in the lowest set of holes.. The spindles i have you can mount in 2 places they need to be at the bottom. Car kept going right. Ended up having a crazy amount of bumpster. Bumpster issue is fixed now but have not been to the track yet. Post a pic if you can

I have a video but cant put it on here. I do have them in the top hole.

A front steer car like a Nova will toe in with wheels in the air. A rear steer car like a Chevelle will toe out with wheels in the air.

Front steer = steering box ahead of the spindles, rear steer = steering box behind the spindles.

quote:

Originally posted by Novacaine:
I have a video but cant put it on here. I do have them in the top hole.

That is the problem 100% move the arms your problem will be fixed.

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Novacaine

How did you make out?

I didnt change yet. I Am on vacation. Will change and test Thursday. Not sure if I have to check the alinement again.

quote:

Originally posted by Novacaine:
I didnt change yet. I Am on vacation. Will change and test Thursday. Not sure if I have to check the alinement again.

FYI i had to make small spacers and change some of the bolts. the way the spindle i had the steering arms i had would not fit flush. But its perfect now less then a 1/8 bumps steer.

If you continue to struggle with it, a quick trip to Junior Carter at Outlaw Motorsports in Halifax, NC will fix it.

quote:

Originally posted by Novacaine:
Not sure if I have to check the alinement again.

You will need to get it re aligned.