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MG MGA - Bump steer--what does it feel like?
|I'm in the process of converting the suspension on my '59 A to B suspension. In article FS-205B on the mgaguru website, the author (Bill Spohn) writes about the problems of this conversion. The second major problem noted, is dealing with the steering arm differences. Either the A's steering rack must be shortened in the middle or longer negative camber A arms fitted to obtain correct steering arm location. But the problem of bump steer possibly remains.|
What does bump steer feel like? Would it feel noticeably different (with the B parts) than the stock setup?
I'm trying to decide whether to cut the rack or use the negative camber arms, although from the article, it doesn't seem to matter--both procedures will produce bump steer.
Just trying to get a "feel" :)
|Good article on it here:|
Don't sweat it. I converted my 1500 to a B suspension setup. I did reuse A coil springs for a time until I got -1" lowering springs. I even slotted the B damper mounting holes 1/16" and bolted those down too. I used my A rack and the issue with the tie rods was that I had to screw them in to almost the end of threads on the outer rod. This didn't leave much for toe adjustment. I just filed a little and ran a die about 3/16" more for adjustments, that's all. I chose not to install negative arms since it makes the steering more 'darty' and heavier.
Ackerman geometries will come into play for bump steer. The A steering is already well designed and running the tie rods in to the end is not noticeable for street driving. I researched it and the articles I read about many production vehicles having major geometry issues made me confident that a little adjustment to the A won't matter and it didn't.
|Thanks to you both! I feel better.|
|Jack, my car definitely suffers from bump-steer, or at least, much more than I remember my previous MGA with standard suspension had.|
It has had the suspension stiffened and lowered by almost 2 inches, negative camber suspension arms and a front anti-roll bar.
I love the instant steering response that this gives the car and it is an absolute delight to drive it around the British country lanes.
The down side to this is bump-steer.
I find that if I hit a bump with one front wheel at "illegally" high road speeds, instantly the car can physically steer over about a foot to one side.(it feels like more!). It has almost put me onto the grass verge once or twice, luckily most bumps tend to be near the edge of the road!
I have learnt to live with the effect and I have found that the best way to deal with it is by letting the car do its thing and stabilise. I find that if I react too rapidly with the steering wheel, I am likely to worsen the cars reaction.
I would think that this suspension set up would be ideal on a smooth race track or for auto tests but not really suited for relaxing long distance cruises.
Kind of depends how you like to drive your car.
|Jack, do NOT fit negative camber A arms from an MGB, as depending on how you fitted the B suspension, you may end up with excessive negative camber.|
I'll have to get Barney to amend my description to add that comment.
Just get a die and run it up the tie rods a little further, and see if the tie rods will go up far enough before they bottom to allow it to be aligned properly.
If not, then also saw off a small bit from the end of the tie rod so that the end no longer bottoms and you'll be able to get enough leeway for a proper alignment.
It simply isn't worth shortening the rack in the middle for a stret application.
This thread was discussed between 03/06/2011 and 06/06/2011
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