Wedge TR7 wheel alignment

Does anyone know what the wheel alignment specifications for a '79 TR7 are?

0" to 1/16" toe-in

Michael,

Thanks for the information. I am trying to solve a wheel shimmy and pulling problem. It has been a gremlin on my 7 ever since it was new so it is not just a matter of suspension wear over time. According to the British Leyland Technical Training booklet on suspension incorect caster can cause wheel shimmy and incorrect camber can cause the car to pull to one side. Although I realize that toe is normally the only thing adjustable on the 7 I suspect something in the front suspension may be bent or perhaps the strut mounting holes are not exactly in the right position. So, does anyone know what the caster, camber, and ball joint inclination specs should be or where I may obtain them? Thanks in advance for any information you can provide.

Michael,

Thanks for the information. I am trying to solve a wheel shimmy and pulling problem. It has been a gremlin on my 7 ever since it was new so it is not just a matter of suspension wear over time. According to the British Leyland Technical Training booklet on suspension incorrect caster can cause wheel shimmy and incorrect camber can cause the car to pull to one side. Although I realize that toe is normally the only thing adjustable on the 7 I suspect something in the front suspension may be bent or perhaps the strut mounting holes are not exactly in the right position. So, does anyone know what the caster, camber, and ball joint inclination specs should be or where I may obtain them? Thanks in advance for any information you can provide.

From my Bentley manual:

Front wheel alignment: 0-0.062" toe-in
Camber angle: 1/4 degree negative <u>+</u> 1 degree
Castor angle: 3 1/2 degree positive <u>+</u> 1 degree
Kingpin inclination 1 1/4 degree <u>+</u> 1 degree

You can also look into the wheels themselves. There's a thought that overtightened lug nuts warp the wheel making all adjustment and balancing pointless.

You may be able to spin up the wheels to check this at a local tire dealer or you may try switching out various wheels on your front end.

Do you mean shimmy as in steering back and forth or a shake that you normally associate with unbalanced tires ?

Thanks for the info. That's a nice picture of your 7. Utah, right? I took my 7 to western Colorado / Eastern Utah (Moab /Colorado river valley)a couple of years ago. Last year went to north Utah. Just got back from a vacation to Grand Canyon north rim and southern Utah (Zion and Bryce). You live in a interesting and pretty part of the country.

Richard Knowles aka "weed"

Naw, I am afraid it's not something as simple as wheels or anything (I wish). I purchased the car new and after 25 years of replacing tires, wheels, alignments, countless rebalancing, suspension rebuilds and upgrades, etc. all I have managed to do is vary the speed at which the wobble (shimmy)occurs. It will happen somewhere between 50 and 70 mph depending on what state of tune and what combination of parts are on the front suspension. It has been quite frustrating to say the least. Good thing I am stubborn old f...t. Two things to note: The car arrived at the dealer with a bent tie rod (replaced) and has always pulled to the left but has never had any odd tire wear. A couple of theories I have heard is that the suspension might have been
bent by overtightening the hold downs during shipment or that the strut mounting holes may not be drilled exactly right at this particular factory. Both theories might explain why some 7's wobble and some track like a laser but who knows?

Anyway the point of this rant is I have a decision to make. After ~160,00 miles I need (and am willing) to put some serious money and time into the car. But I can't see the point in doing it if the car is still going to drive like crap. Don't want to give up quite yet but I need to solve this problem.

Thanks for all the help, encouragement, advice, etc. you guys can provide.

Richard Knowles aka "weed"

Yep, northern Utah to be exact. That spot was about 40 miles ease of Ogden on state road 39. The wife snapped the picture last year on our "fall colors" drive.

Hi Weed,
I admire you for being so persistent. The common causes of shimmy would be bent wheels or tire runout, too much castor, & possibly wrong camber angles. A bent strut or control arm could change castor and or camber quite a bit. I assume that these parts have been replaced or checked somewhere along the way & are not bent.

While it is true that castor & camber are normally not adjustable, they can be changed by slotting the body mounting holes for the "turret top" as they call it. You would need to move the turret top forward to reduce castor, outward to increase camber & vs. The specs that Rich gave allow quite a bit of variation. The castor angle of 3.5 degrees plus 1 degree that Rich gave would be 4.5 degrees positive which could be the cause of shimmy. Maybe the factory DID screw up. It wouldn't be the first time.

I would suggest having a "good" alignment shop check & record the numbers. I would go for a castor angle of 2.5 degrees positive or less. As little as 1.5 degrees would probably work ok. As noted above, it can be changed. I would go for a camber angle of zero to 1/2 degree negative. The success of the project depends upon the willingness & capabilities of the alignment shop that you select, & whether they are willing to make the necessary sheetmetal modifications to move the "turret tops". They might require up to 1/2" of movement. (Slotting)

There are readily available castor & camber gages that you could use to check things yourself, but this may not be the time for a completely new learning experience. Good luck.
D

As a matter of fact, there are aftermarket kits you can install to make castor and/or camber adjustable. I found one such vendor when researching issues with my own, lowered suspension. I can't vouch for them, but here's a link to their website. Triumph alignment

Once again thanks for the information. I am aware of slotting the strut mounting holes as a possible solution. One of the two Triumph dealers in Houston (where I bought the car) use to do this to all of the wedges before they left the lot. I was not aware of this at the time and picked the dealer that didn't. I bought a used TR8 that had this modification and there are no problems with wheel shimmy. With the new information you guys have provided this will probably be the route I will take to solve this problem. Trying to find a frame / alignment shop in the Austin, Tx. area that will work with me and won't brake the bank should be a challenge though. I allready have a strut mounting plate(s) that my father made for me a few years back so that is out of the way. Some things I wonder about for this procedure: Can the strut mounts be slotted with strut assemblys still on the car? If so what tool would you use to do that? That would seem to be the simplest way to find out if this procedure is valid for this particular car. Or perhaps it would be better to remove the stut assemblys and drill out the holes (assuming there is enough metal to allow it) so that the strut mounts can be moved in any direction for adjustment? The front suspension is pretty worn right now. Do I want to go ahead and spend the time and money to bring it up to snuff before starting the slotting project?

Argh!! Decisions...decisions. Part of the joy of owning a LBC I guess. Opinions, advice, sympathy greatly appreciated.

"weed"

Weed,
It would probably be much more simple to get one of the kits that Rich suggests above. It looks like it "should" have the required adjustment range.

If you wish to slot the holes, jacking up the car with the top of the struts disconnected at the top will give working clearance. Anything from a rat tail file to a to a 3/8" to 1/2" cylindrical, CARBIDE, rotary file in a die grinder will make quick work of the slotting. As an example, if the strut length is 14", moving the top 1/2" would change the castor or camber by about 2 degrees. Obviously, a different slot length would be required for a different strut length. I'm only guessing at the strut length. If you slot the holes, you need to drill an extra hole & put a 1/4" bolt through to anchor the strut mount in it's final position, once you find out where it needs to be. However, I still think that the above kit would be far easier, I didn't know that a kit was available. This way, neither you or the shop will have to do any cut & try slotting.

By all means bring it "up to snuff" before making any changes. It might just be ok after a complete rebuild. It will likely change the required settings in any event.
D

Thanks for starting this informative thread Weed. I guess the shimmy in my 7 isn't normal after all. Mine was at 45-50 'til I put new tires on, then it shifted to 50-55. Have learned to live with it by driving the speed limit when it's below 50 and ignoring the speed limit when it's 55."Ignore" is one of the few things I do well anyway. /ubbthreads/images/graemlins/crazy.gif

As part of my job I routinely deal with alignment problems on many types of cars. It is my opinion that slotting the tower is NOT a repair at all and will only mask a potentially dangerous problem. The first step is to have a GOOD alignment shop do a complete check and print out all the angles, caster, camber, toe, SAI and thrust(setback)Now an experienced front end man will be able to "read" this and infer where to look for the real problem.
I wont try to guess from here, but you discribe a caster pull like problem. trying to balance that with camber pull the other way is a bad idea.......
MD(mad dog)

Rich,

Thanks. The K-mac kit appears to be the way to go for TR7 wheel alignment but certainly not the cheap way. But if it cures the wheel shimmy curse it will be worth it. The car was never cheap to own anyway. Oh well.....guess I might as well get started rebuilding the front end. If this works I will certainly let everybody know. I don't think I have the only 7/8 with this problem. Anybody out there tried the K-mac kit?

Happy motoring y'all

REK "weed"