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Discussion Starter · #1 ·
Is it normal for the outer tie-rod ends (mine are Forte's bump steer kit) to make contact with the lower control arms when the frame is on jackstands?

I assume this comes close to simulating 'full droop', and so I don't think you would want any contact with your steering gear at any point!?

I have 95 donor front lower control arms & spindles, donor power rack, FFR (shorter) inner tie-rod ends and Forte's bump steer ends connected to the steering arm.

Most people have suggested I probably do not need to correct bumpsteer with my setup, but I got it from Mike Forte just in case. :rolleyes:

It is connected as the factory tie-rod end would be (comes up from the bottom), with a single 1/8" spacer between the rod end and the steering arm. I have not done any kind of alignment, and the fronts do have a significant amount of toe-in as it sits up in the air.

Turning the steering wheel causes the outer ends to touch the upper surface of the lower control arms about 3/4 of the way through it's full lock to lock rotation.

I don't know if this will improve once the alignment is done, or if I need to change something.

Thanks,

Sean

[ November 26, 2006, 02:41 AM: Message edited by: canuck1 ]
 

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I have fox spindles but had a similar problem.
I just ground off a little bit of the casting to give clearance. I didn't want any contact between the tie rod end and the steering arm.
 

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Discussion Starter · #3 ·
Originally posted by Mike_C:
...I just ground off a little bit of the casting to give clearance...
But they are sooo pretty! :D


They also don't really have a 'top or bottom' to grind, so any adjustment would mean the bit I ground off wouldn't be where it needed to be. I'm pretty sure your solution would work for OEM tie-rod ends though. Thanks Mike.

Sean
 

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I'll bet when you get them on the way you want them with the spacers correct; they will not hit. I assume you have the ends for the SN 95 spindles? Mike wouldn't do that to us. :D I have a pair yet to be installed.
 

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By "casting" I meant grinding off the edge of the steering arm, not the heim joint. Just a little bevel where it was getting close. I also added safety washers on top of the joint so it can't possibly come fully apart.
 

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Discussion Starter · #6 ·
Thanks again Mike,

I guess grinding the steering arm would defeat my ability to adjust for bumpsteer (if necessary)? Technically, I should be able to adjust it by adding or removing spacers to minimize bump-steer. right now, I can't make it work with the thinnest possible spacer in place.

I realize with these outer tie-rod ends I CAN mount them on the top of the steering arm. That would definitely solve the problem I am having right now. Problem is everyone has already told me I should mount them to the bottom of the steering arm!? :confused:

I have lots of clearance when set at ride height, but I just want to be sure I can still steer when I come upon a full droop scenario.

Any other ideas? Am I worried about something that will go away once aligned??

Thanks
 

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just another builder
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maybe get the offset bushings to raise the rack and put the tierods on the spindle from the top...that's what i did on a MKII and it worked out
 

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Discussion Starter · #8 ·
Thanks quicksand,

I'm sure you are correct, this would resolve my current issue. I am just not sure what the (handling) consequences would be if I were to raise the rack and mount the tie-rod ends on top in my MK III?

Anybody had to deal with this clearance problem in a MKIII or with the early SN95 style donor front LCA's?

Thanks,

Sean
 
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Guys, I just spent a lot of money to correct the bump steer problem on my Cobra. Just installing the kit will not correct the problem, you have to keep checking bump untill you adjust the bump steer problem out. In most cases the tie rods will parallel the lower control arms when bump steer is minimized. In the above photo the tie rods are no where near parallel to the lower arm.I could be wrong but I can't see that working properly.
 

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just another builder
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Roger...i should have mentioned the pic above was taken during trial fitting...i am familiar with bump steer (causes and cures)...i was addressing Sean's interference issues.

that said, because of the racks we use and the geometry handed to us by FFR, bump steer can only be minimized... custom machined rack extenders (like dv/dt's) on the other hand can eliminate it all together (if applied properly with the other components)

[ November 26, 2006, 09:52 AM: Message edited by: quicksand ]
 

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I've installed Forte's Bump steer on my MKIII. Check out the photos. I researched the bump steer cause and effect also and ended up with the Heim jpints on top to get the tie rod ends as close to parallel to the lower a-arm as possible.



The second picture shows the rack bushing adjusted to put the rack as high as possible ... also needed to get desired parallel geometry.



I'm not to the go-kart stage yet ... but soon. If anyone has experience with this set-up, I'd also appreciate feedback on set-up.

Pete
 

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Canuck1,
Additional info. I called Mike Forte before installing the rack to ask about the position of the rack bushings. He said that the kit was designed for the rack to be adjusted as high as possible. I didn't know to ask him about the location of the Heim joints at that time, but putting them on top is the only way to make the geometry work. No interference too. I'm sure a call to Mike would clear it up.
Pete
 

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Sean- before you go modifying the bumpsteer parts, set your car up for minimal bumpsteer first.


The advantage of the bumpsteer kit is that it can be mounted above or below the steering arm, and then spaced out as needed. THIS is what gives it it's bumpsteer minimizing characteristics.

In a MKIII with SN95 spindles you will find bumpsteer is minimized by mounting the arms on TOP of the steering arms.....no trimming will be necessary...


-SB
 

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Here is a outstanding article...

www.maximummotorsports.com On the left of Home page goto "Instllation Instructions" then to Steering finally, left click (MMTR-1,-3, and -6)
The tapered sleeve on Mike Forte's kit saves a lot of time...you'll note other kits require drilling the steering arm to 5/8". Anyway, the article goes on to a excellent discription of 'bumpsteer' and its relationship to steering box location, etc. Very worthwhile; lengthy. Hope this helps the discussion.
 

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SB, Correct me if I am wrong here but if the kit contains a tapered spindle for the steering knuckle how can it be mounted either top or bottom of the knuckle. Tho whole idea of the taper is to form a secure mount?
 

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Roger,
Check out the first picture in my earlier post. The tapered sleeve fits snug in the tapered hole in the steering arm. There's a spacer above and below the tapered sleeve insert. The bolt is just a straight bolt providing clamping force for the whole sandwich. It's not going anywhere.
Pete
 

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Discussion Starter · #17 ·
Thanks everyone for the replies.

I had it explained to me (by a member much more experienced than me) that the SN95 spindles with the 95 LCA's have different bump-steer characteristics than most people experience.

Because the arms mount in the inner set of holes, the LCA pivot point is actually closer to the pivot point of the inner tie-rod end. It's not the 1 1/4" (?) that DV/DT's rack extensions come out, but closer than the outer mounting location and so bump-steer is 'less' noticable than with FOX donor LCA's or even FFR tubular LCA's which both mount in tbe outer set of holes. I learned this after I had purchased the bump steer kit, but decided to use them anyways. I thought this would give me a better chance to be able to dial out most of the bump-steer that remained.

I confess, I did not call Mike Forte first :eek: , but being on the left coast sometimes makes calls during working hours difficult.

Pete,

I have a set of offset rack bushings, but was told by FFR that they are not required with the MK III since they altered the rack location to improve it over previous iterations.

Looks like you have a different rack (FR manual?) as well as the black adjustable upper control arms where the upper ball joint sits at a different angle than the gold ones I have. Not sure how much difference that makes?

Roger you and Quicksand are both right. Yes, I realize adjusting for bump-steer is a process which involves repeated adjustment and measurement, but I would like to know if anyone thinks my 'contact' issue is a problem before I go any further. If bump-steer measurement suggests I need to move the tie-rod end lower, I can't. (there isn't enough clearance right now!) If I move it to the top, will I be severely handicapping my ability to minimize bump-steer?

Mumbler, Sporty,

Thank you for the excellent bump-steer reference. I think I am fairly up to date on the physics now, just not sure If my starting point is correct. Sporty suggests I will find it will work better starting at the top of the steering arm (opposite of OEM), but others have already told me I will have more success mounting below the steering arm. :confused:

It's my oddball collection of components that confuses the issue here. Sure would be nice to find someone with th same parts who could point me in the right direction. As it stands, safety seems to be pointing me in the same direction as most here have suggested. I'll start on top. If the bump-steer issue can't be minimized with the components I have, I'll have to seek another solution.

Thanks again.

Sean
 

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Incidently, when putting the parts/spacers on for testing 'bumpsteer' curve, use a lug nut Vs the lock nuts provided (from Mike Forte). Lock nuts should only be used once. Get extras if necessary. :rolleyes:
 

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Discussion Starter · #19 ·
Thanks Mumbler,

You are correct about the stover type lock nuts. I have a couple non-locking nuts on for mock-up.

FWIW, here's one of the MANY bump-steer posts that has confused the issue for me:

Bump-steer orientation?

Sean
 

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Sean,

I have FFR LCAs on my car, plus the offset rack bushings, so my car might require a different setup than yours. I measured bumpsteer in many different configurations, and found the least amount of bumpsteer (almost nil) was achieved with the rod ends right on top of the arms (ie no spacers).

- SB
 
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