PROSOUTH

Does anyone have a good picture of the bumpsteer blocks installed ? Could you post them or E-mail them to me? I bought a set and I really need some more information on them to get the whole concept down.

PROSOUTH@Charter.net

redvetracr

PRO,
What is the problem?? The two (straight) holes line up with your steering arm (after you drill the holes straight) and the tie rod goes into the third hole. Did you buy the Guldstrand tie rods themselves?? Your factory rods will probably be too long. If your interested I have a brand new set of Guldstrand tie rods for sale. e-mail direct redvetracr@msn.com

norvalwilhelm

PROSOUTH If what redvetracr says is true and it looks like that in the pictures then all you are doing with the blocks and shorter tie rods is lowering the outer tie rod a fixed amount. You are trying to get the tie rod to point to the instantanous center which changes with ride height.
To me the bump steer studs are alot simpler to install and are totally adjustable. You can set 1/2 inch lower , test it, change it to 3/4 etc. etc and they cost a little less.
One of our problems is the tie rod is not long enough so we have to change the inner mounting point on the center link and while we are at it it can also be raised.

PROSOUTH

Norval, I got a deal on these from a friend here on the Forum. I thought I would try them.

Now, if the blocks and shorter tie rods lower the outer tie rod attachment point and attempts to get the tie rod to point to the instantanous center isn't this what I was wanting to do?

redvetracr

Norval,
Please don`t take it personal BUT what Guldstrand sells for the "average guy" works, I don`t care why and I don`t care how it just does. I also believe parts like "bumpsteer blocks", "spreader bars" and the "real deal 5-link" among other things were designed by GM engineers back when someone (at GM) cared about the C-2/3 chassis. You are right however, the fastest Corvette at Road America/ Elkhart lk. WI last month (probably the fastest in the country) has a center link that has the INNER tie rods on top of the link along with the outer moved down, BUT I think they just spaced the outers down (NO blocks) and used a heim joint (this car also has "mega bucks" invested in it and a $30K small block to boot!!). ...redvetracr

68427

I just bump steered mine with the Guldstrand blocks and it has reduced bump steer, so it works. But I still have a some toe-in under bump which I would like to eliminate, I figure I need to lower the outside another 1/2" to be right. I like better the idea of mounting the inner tie-rod to the top of the center link to achieve the same thing.

BTW: maiden open track venture for this car at Thunder Hill on the 12th, so I'll see how it works.

Mark70

In talking to Dick, he also said that the bumpsteer blocks increase the turning radius of the car, and so he didn't recommend them for a street driven Vette. I decided against them for my car. Have any of you using the bumpsteer blocks noticed the increased turning radius?

ImBatman

OK I need a lesson in bump steer 101. :D What is it and what do these kits do for you. I have gone at my car with the idea of making it a good handler. I already have the performance kit from VB&P which includes Bilstein's, 550 springs, adjustable front and rear tie rods, rear xmember locating disks etc, etc. Also going with a spreader bar and 17" wheels and tires. Should I look at one of these kits for my car? :confused:

flynhi

The blocks that ProSouth is installing were on my 71 SB for several years. I'm not a racer but do drive agressively from time to time and I noticed no adverse effects. I admit that I'm not knowledgeable enough to evaluate them.
I removed them to install Steeroids.

However, even a novice like me will immediately notice the difference with a spreader bar.

norvalwilhelm

) has a center link that has the INNER tie rods on top of the link along with the outer moved down, BUT I think they just spaced the outers down (NO blocks) and used a heim joint

redvetracr. This is exactly what I was talking about. The bump steer studs go in the outer tie rod location and come with spacers to custom adjust the height of the outer tie rod. It also comes with 2 heim joints to replace the outer tie rods. The complete kit comes from Coleman's and cost about $60 american.
Also our tie rod sleeves are too short so while moving the inner tie rod location move it up and weld it on top of the center link.
I have the proper bump steer gage with the dial indicator and wheel, plus aluminum plate and have worked with the bump steer stud to get bump down to .015 but my bump up is still out of range. I did get 1 1/2 inch longer tie rod
sleeves and will install them along with new mounting points this winter.
What I was saying is that the bump steer studs work the same as the blocks , cost half the price complete with heim joints for the outers and are adjustable.
Just because an engineer designed something doesn't make it right.
After all our cars are totally engineered by engineers and we still seem to need to change them.

norvalwilhelm

I just bump steered mine with the Guldstrand blocks and it has reduced bump steer, so it works. But I still have a some toe-in under bump which I would like to eliminate, I figure I need to lower the outside another 1/2" to be right. I like better the idea of mounting the inner tie-rod to the top of the center link to achieve the same thing.

68427 This is the problem I ran into. The blocks or dropping the out tie rod in not enough. Our tie rod sleeves need to be longer , so the only alternative is to move the inner tie rod mounting location about 1.5 inches more towards the center and while we are at it raise it. The only way to weld another mounting point is to the top or bottom, the center is not an option.

norvalwilhelm

This is a drag link that has been modified. An old link has the holes cut off and rewelded to this center link. It has not yet been cleaned up but the holes are moved higher up on the link.
Double click to enlarge

norvalwilhelm

BlackRat Bump steer is when the wheels turn themselves without an input from you. As the car becomes air born like flying over a hill the front tires point inward or tow in really bad, even 1 to 2 inches. When the car comes down whatever wheel has the most load can cause the car to shoot in that new direction causing you to loose control
The opposite happens when you come down a hill , hit the bottom of a gulley and start back up the other side. The suspension compresseds, the tires point out but in this case both tires are loaded heavily and one doesn't tend to steer the car.
The worst case is comming down a hill, at a high rate of speed, there is also a small creek in the bottom of the gulley with a bridge, so you are flying down the hill, hit the bridge the front end compresses, bump out, the car goes over the bridge causing the suspension to unload, extreme bump in, the car hits the other side of the bridge and the front suspension is once again compressed as you start up the other side, extreme change from toe out to toe in agian and whatever tire is loaded the heaviest will start to drive the car in that direction.
I have been there, done that and almost had a bad crash because of it.
NO more. My bump steer is almost gone and I can do that same hill/bridge at 100 mph without any feedback.
Nice feeling when the suspension goes through it's travel without any darting of the car.

ImBatman

Thanks for the education Norval. I have heard this term many times but never new what it meant. I remember hearing a tech segment on speed channel a while back talking about how NASCAR does not allow the anti bump steer stops.

Thanks
Wade :thumbs:

68427

Norv, thanks for the drag link picture. I'll save this mod for the winter.

PROSOUTH

Uhhhhhhhh Norval, I may need that center link so don't let it get away!!!!!

I have the Gulstrand Blocks and VetRacer has some more of the parts for me. I figure that somehow I will make all of this work with the Jeep steering box.

I have to cut the frame to insert the plate to hold the Jeep box and I may be able to correct some of the bump relationship by raising the box and the Pittman. I'll just have to put it all together and see. At least I will have a good selection of parts to work with. One good thing about the fiberglass front spring is that I can apply or remove spring tension at will and check the travel.

Thanks Jim

norvalwilhelm

Jim raising the box does not address the problem with the length of the tie rods. Ours needs to be about 1.5 inches longer so at the same time as you raise the innere tie rod you have to also lengthen it. The center link that you see in the picture I posted was not for a vet and it did not address the need for longer tie rods.
This winter I will make a link with trial mounting points and do a proper bump steer test without a spring and with a aluminum plate in place of the wheel and the bump steer gage. I will try to find the proper inner mounting length and height and once I find it I will weld proper eyes in this location.
It is a winter project so I can take my time , experiment with different lengths of tie rods and different mounting positions.
I certainly will post results at the time.
Last night my wife and I went for a ride and she commented on how stable my steering was compared to a few years ago when the car was so darty.
So far the largest change came from slotting the A arm cross shafts and dialling in 5 degrees of caster.

PROSOUTH

Norval, I was thinking that by being able to change the location of the original steering box that I would be able to actually stage the whole system. To be able to raise or lower the steering box and pittman as necessary and then lengthen the tie rods or whtever is necessary to obtain the proper relationship needed,

I still have the picture of the geometric lines of the front suspension that Twin Turbo drew up and I could see that one the limiting factors was the permanant attachment point of the sterring box. JIM

norvalwilhelm

Jim I kept Twin Turbo's drawing also for reference.
Sure you can raise or lower the box but that is not easy. If you drilled the frame for mounting holes how do you raise/lower it without making more holes?
To lengthen the tie rods you need to weld up another center link. To cut our existing link is difficult because of the power steering control valve and the idler arm must remain parallel to the body when the car is pointed straight ahead.
You can not weld a eye for the inner tie rod in the center of the rod, you must either weld in on the top or the bottom of the existing center link. There is no in the middle.
I can not make my center link until I make the extended spindles for my raised roll center, that affects bump steer so I have to do things in the proper order.
Pete or redvetracr could really help us here but then again when I think about it what do we need?
In the last year I have really noticed a big difference in the car's steering with the rebuilt steering box and that means new bushings, the 5 degrees caster, the pump steer outer studs and careful setting of the toe.
Jim we seem to be the only ones concerned with this bump steer problem and guys it is a real problem unless you add really stiff springs to overcome any movement.

Twin_Turbo

youa re not alone, I have seriosu issues with out camber and bump steering problems. Was there any more discussion since the last thred died?