12" Brake Swap: Bumpsteer Issues or No?

[Scoti]

My buddy & I have been debating the 12" disc swap on the Malibu. I want bigger brakes but don't want to make something that wasn't a good handling car from the factory even worse.

For those that have done the swap, what's your take on the issue of 'increased bumpsteer' from the B-body spindle swap that's been kicked around all the web sites these days? Years ago this was the hot ticket, now it's 'bad news'.

I know Marcus @ SC&C makes (or markets?) a killer spindle conversion but with several projects going on @ once, I must spend wisely. If they were cheaper, I would go that direction.

The car currently has dropped spindles, 600# springs, a 1 3/8" sway bar & poly front bushings. It does handle better than an original g-body, but I want the bigger brakes.

Let me know your experiences w/the 'B' spindle/12" brake swap.

 

[DeltaT]

You do not need any bumpsteer compensation when you go to the B-Body spindle & 1LE brake setup. The tie rod moves out just a bit, but not up or down. I have done this twice now. I even have the Baer Trackers with the adjustable bumpsteer and the best setting is factory height. My car is lowered but not slammed. I have never heard anyone that's actually done it to their car call it bad news, though it seems to be a persistent rumor.

I have the Global West modified B-body spindles on the car now and love the setup. I upgraded to the 13" Wilwood front brakes.

If you're interested, the 1LE Brake/B-Body spindle kit, assembled, is for sale in the Parts Section. I just posted it today for $300 plus shipping. It has Performance Friction pads. All details and pix here:

http://www.maliburacing.com/forum/viewtopic.php?t=35163

Jim

My Site with Pix: http://home.mindspring.com/~jim_fisk/id1.html

 

[355_79bu]

No bumpsteer isues for me either. I am very pleased with the handling and braking improvements with the b-body swap. I used all GW stuff (springs, control arms, and bushings) with stock b-body spindles from the local U-pick.BTW: I have no bumpsteer kit, or anything else to change the geometry either.

 

[Duts87ss]

Some people do notice the bumpsteer and others dont. The B-spindle swap *will* cause added bumpsteer. The roads in your area will determine how much of it you actually notice.

Delta, if you want to hear from people who have done the swap and didnt like it, cruise over to montecarloss.com. There's at least one guy who has done the swap and then gone back stock.

The factory steering arms on a G-body are too low from the factory; adding the B-body spindles lowers the arms even more. This is the reason that the Bear Trackers dont work on our cars. The optimum mounting point is about center of the factory steering arm.

If you just want bigger brakes, email Ed at [email protected]. He does LS1 and C5 (as well as other) brake swaps to G-body spindles. You may have to send him your spindles to be fitted with the parts, though. He normally sends a set of stock spindles with his kits and then you send you old spindles back for core; this is the reason I mention sending your to him.

 

[5-door]

I'm still using the stock spindles and brakes, but you could always get a bumpsteer kit like the one I have. It's from Speedway. Keep in mind that my front end has a lot of work done to it and a stock G-body front end will never see an extreme angle like you see on mine in the picture. If it works for a setup like mine with that extreme angle, it will damn sure work on yours.

 

[DeltaT]

if you want to hear from people who have done the swap and didnt like it, cruise over to montecarloss.com

I see guys over there that don't take the time to make their mods work as an entire package - they throw on something and don't tune or re-align the car, or they're unhappy with the B-body spindles but it's really the fact that they went too stiff on the springs, etc. There are exceptions, of course.

I went through 4 different spring combos and 3 different antisway bar combos before I got the car to handle how I wanted it. After settling on a combo, I took the time to dial it in. The car, with those spindles and brakes on it, handled well enough to allow to me change lines in the middle of an off-camber downhill. I also have 3" adjustable spring perches in the front so we could adjust corner weights and get the car very neutral.

After all that setup, I had no bumpsteer issues. And the roughness of the road won't make a difference - there are some big rollers bumps around here that make me hit my bumpstops occasionally, and they did not upset the car either.

Poor caster or camber setups can do things that feel like a bumpsteer issue. It's hard to find someone who has all their stuff actually set up correctly.

I don't go by what other people say on a web site, because a lot of that is them spouting crap that they read on another website, or their cousin heard from his friend's dentist! I go by what I did and what I found out and what I tested. I found no bumpsteer problems with the B-Body spindle conversion, otherwise I wouldn't have it on the car now.

Here's a quote from the montecarloss.com website:

12-inch 1LE Brake Upgrade:

"I am thoroughly impressed with this upgrade. The braking is awesome in comparison with the stock setup... IMHO, an awesome handling car that's very comfortable on city streets. " - George Dumpit

Jim

 

[Duts87ss]

On these rolling bumps, were you hitting them with both wheels or only one side?

I'm getting my information from people who have actually measured the bumpsteer after the B-spindle swap. Check out jeffd.50megs.com for a fix to the bumpsteer problem for G-bodies with the B-spindle swap.

Springs and sway bars wont get rid of or add bumpsteer; its in the steering geometry.

 

[gmachinz]

When I did my first B-body swap on my own '78 Monte, I did not notice any bumpsteer problems afterwards. Having said that, I somewhat agree that to see the full capability of the swap, you need a GOOD gearbox and all new suspension underneath. I opted for the quick ratio 'box from a 1LE Camaro, Bilstein shocks, Hotchkis arms, stock springs cut 1/2 coil and new suspension/bushings. Combine that with 275/45/17 rubber with 17x9 wheels and I have a damn good handling Monte. Bumpsteer just isn't an issue for me/us when we do the spindle swaps thus no need for altered spindles. -Jabin

 

[Duts87ss]

Some good reading on bumpsteer: Click Here

And a quote from that post:
Only after I installed the center link modified to reduce bumpsteer, did I realize how big a problem it is. The difference is very noticeable when driving the car fast. Even just driving down the highway is improved. Much better directional stability in all conditions. With little or no bumpsteer, the car will follow the same line around a corner, bumps or not, without having to make minor corrections to keep it on line.

I didn't measure it, but estimate about 3/8" total toe change from full droop to full bump. That is a lot! After installing the modified center link, I used a laser pointer mounted to the spindle to draw a line on a piece of paper 3 feet from the car. It drew a very straight line up until about 2 inches from full droop. Of course, I didn't think of this method of checking until after removing the stock center link! Changing the shims would change the angle of the line, as toe change returned. Very interesting.

But, bumpsteer is something you would definitely miss, if it was suddenly removed from your car. I guarantee.

--------------------
Jeff Davidson

 

[LS6 Tommy]

Some good reading on bumpsteer: Click Here

And a quote from that post:


I didn't measure it, but estimate about 3/8" total toe change from full droop to full bump. That is a lot! After installing the modified center link, I used a laser pointer mounted to the spindle to draw a line on a piece of paper 3 feet from the car. It drew a very straight line up until about 2 inches from full droop. Of course, I didn't think of this method of checking until after removing the stock center link! Changing the shims would change the angle of the line, as toe change returned. Very interesting.

But, bumpsteer is something you would definitely miss, if it was suddenly removed from your car. I guarantee.

--------------------
Jeff Davidson

True. If you measure the bumpsteeer on a 100% stock G-body I bet it's almost the same.

Tommy