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drop spindles
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DRR Sportsman
Picture of Novacaine
posted
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.
 
Posts: 116 | Location: North Carolina | Registered: May 07, 2003Reply With QuoteReport This Post
DRR Sportsman
posted Hide Post
Sounds like in the changes the bumpsteer was changed.
 
Posts: 284 | Location: Going to or returning from the chipmine. | Registered: July 01, 2011Reply With QuoteReport This Post
DRR Sportsman
Picture of Novacaine
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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?
 
Posts: 116 | Location: North Carolina | Registered: May 07, 2003Reply With QuoteReport This Post
DRR Sportsman
Picture of FastLane
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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.


Do not argue with an idiot. They will drag you down to their level and beat you with experience.
 
Posts: 313 | Location: Parked... | Registered: May 27, 2007Reply With QuoteReport This Post
DRR Pro
Picture of Brktracer
posted Hide Post
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.


Matt Ward



 
Posts: 1246 | Location: South Carolina | Registered: March 20, 2004Reply With QuoteReport This Post
DRR Sportsman
Picture of Novacaine
posted Hide Post
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.
 
Posts: 116 | Location: North Carolina | Registered: May 07, 2003Reply With QuoteReport This Post
DRR Sportsman
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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.
 
Posts: 284 | Location: Going to or returning from the chipmine. | Registered: July 01, 2011Reply With QuoteReport This Post



DRR Sportsman
Picture of Novacaine
posted Hide Post
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?
 
Posts: 116 | Location: North Carolina | Registered: May 07, 2003Reply With QuoteReport This Post
DRR Sportsman
Picture of FastLane
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It will help but these cars have this issue naturally. You need to fix the issue, not bandaid it.


Do not argue with an idiot. They will drag you down to their level and beat you with experience.
 
Posts: 313 | Location: Parked... | Registered: May 27, 2007Reply With QuoteReport This Post
DRR Sportsman
Picture of Novacaine
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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.
 
Posts: 116 | Location: North Carolina | Registered: May 07, 2003Reply With QuoteReport This Post
DRR Sportsman
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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.
 
Posts: 308 | Location: coquille,or | Registered: November 18, 2003Reply With QuoteReport This Post
DRR Sportsman
Picture of RacerVX54
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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


"Just Shut Up and Race"

Brian Martin
Martin Racing
5.66 @121.55
 
Posts: 890 | Location: Va.Beach .Va | Registered: August 03, 2005Reply With QuoteReport This Post
DRR Sportsman
Picture of Novacaine
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I have a video but cant put it on here. I do have them in the top hole.
 
Posts: 116 | Location: North Carolina | Registered: May 07, 2003Reply With QuoteReport This Post
DRR Sportsman
Picture of SlyFox
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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.


Mike
 
Posts: 916 | Location: Marietta, GA | Registered: December 09, 2005Reply With QuoteReport This Post



DRR Sportsman
Picture of RacerVX54
posted Hide Post
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.


"Just Shut Up and Race"

Brian Martin
Martin Racing
5.66 @121.55
 
Posts: 890 | Location: Va.Beach .Va | Registered: August 03, 2005Reply With QuoteReport This Post
DRR Sportsman
Picture of RacerVX54
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quote:
Novacaine
How did you make out?


"Just Shut Up and Race"

Brian Martin
Martin Racing
5.66 @121.55
 
Posts: 890 | Location: Va.Beach .Va | Registered: August 03, 2005Reply With QuoteReport This Post
DRR Sportsman
Picture of Novacaine
posted Hide Post
I didnt change yet. I Am on vacation. Will change and test Thursday. Not sure if I have to check the alinement again.
 
Posts: 116 | Location: North Carolina | Registered: May 07, 2003Reply With QuoteReport This Post
DRR Sportsman
Picture of RacerVX54
posted Hide Post
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.


"Just Shut Up and Race"

Brian Martin
Martin Racing
5.66 @121.55
 
Posts: 890 | Location: Va.Beach .Va | Registered: August 03, 2005Reply With QuoteReport This Post
DRR Trophy
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If you continue to struggle with it, a quick trip to Junior Carter at Outlaw Motorsports in Halifax, NC will fix it.
 
Posts: 130 | Location: Ashland,Va | Registered: March 29, 2003Reply With QuoteReport This Post
DRR Sportsman
Picture of David_D.
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quote:
Originally posted by Novacaine:
Not sure if I have to check the alinement again.


You will need to get it re aligned.


David Deming
1974 Chevy Nova Custom Hatchback
Horsepower Innovations E85 Carb
 
Posts: 295 | Location: Nampa, ID | Registered: October 25, 2006Reply With QuoteReport This Post
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