Rear camber adjustment

[pedlar17]

I have a new CTM chassis with all new rear shocks, springs and poly bushes.

The problem is that the near side is at zero degrees, with standard brackets but the right hand is about 2 degrees positive. I have checked all parts and cannot find a solution to get the right hand to zero.

Should I fit non standard brackets?

[jerrytr5]

The adjustable Goodparts brackets make life easier, but you may need spring spacers too.

start here: http://www.buckeyetriumphs.org/technical/Suspension/AdjRS/AdjRS.htm

Jerry

[mikeyb]

perhaps you should talk to CTM?

[RogerH]

Hi Pedlar,

you MUST read the Buckeye link from Jerry.

 

Adjusting the camber is hard work and you only want to do it once (dream on).

 

TRiumph put spacers under the springs to bring the wheels nearer to 0' but this will raise the body.

Very small measurement oddities of the chassis will have an effect on the camber - it doesn't mean the chassis is duff.

 

An interesting point - if you need a weird combination of bracket (3 notches, 2 positions, normal or upside down = 36 combinations) then you may find that the holes in the pairs of brackets do not line up. This could stress the TA as it will try to impart a twist into it.

For this reason I don not think the adjustables are as good as everyone thinks.

 

Do not expect both nearside and offside to be the same brackets/notches.

 

Before you take anything apart, and with the car correctly loaded, get all four corners measured with a Hunter Hawkeye system.

Once measured you can now start your challenge.

[stuart]

How much have you run the car around since the build and have you weighted it as per the manual.

Stuart.

[Dave McDonald]

Pedlar

Could one of the trailing arms be twisted?

Dave

[pedlar17]

I have run the car around 150 miles since rebuild, so everything should have settled down correctly. I don't think the trailing arm is twisted, but do not have anything to check it against.

According to buckeye link, with the current angle that I have, I could get close to zero with a 3u inside and 2d outside.

Do you think it's worth swopping brackets?

[Guest ntc]

Do you have a matching pair of arms ?

[pedlar17]

How would you tell? Both arms look identical, one has the manufacturing date welded on.

[TRseks]

I went for adjustable brackets, some dont like them but makes it easy to adjust camber. To change the standard brackets around seems like a very difficult and time consumable task, and you still probably need to buy some brackets as there are three different types. Even with the instructions on what brackets to use I guess it's could be frustrating.

 

I am in the process to adjust toe in at the rear myself, does somebody know how much the toe in would move after moving just one of the shims?

[John L]

I would love to know how they set these up in the factory at assembly, I'm sure they would have just put them in a std position with a 2 or 3 shims behind the brackets and let them go, I'm sure they wouldn't have had time to set up each chassis on the line.

I'm sure they would have done some tests to see what the average settings where with the different brackets, and then put them on the line like that.

When you see the time allowed do it on a new car with all the latest equipment, I'm sure there must have been an easy way to do it then, does anybody know how it was done in the factory?

John

[jerrytr5]

I went for adjustable brackets, some dont like them but makes it easy to adjust camber. To change the standard brackets around seems like a very difficult and time consumable task, and you still probably need to buy some brackets as there are three different types. Even with the instructions on what brackets to use I guess it's could be frustrating.

 

I am in the process to adjust toe in at the rear myself, does somebody know how much the toe in would move after moving just one of the shims?

For each shim the wheel rim will move approx 2.5mm.

Jerry

[stuart]

How would you tell? Both arms look identical, one has the manufacturing date welded on.

If only one has the date welded on it then you dont have a pair.

Stuart.

[RogerH]

Hi Jerry,

your simple statement For each shim the wheel rim will move approx 2.5mm. is actually quite complicated.

if you remove one shim from each bracket the TA will move forward and not affect the toe-in (but does help the fore/aft wheel alignment by just slightly less than the thickness of the shim)

If you 'remove' an outer shim you will increase Toe-in by X amount.

If you 'add' a shim to the inner bracket the the toe-in will increase by X + Y as you have now move the pivot and you now have different levers.

 

However instead of adding to the inner you simply work on the outer - if possible.

 

One needs to sit and think before attacking this area. Compared to replacing the brackets the shims are easy.

 

Roger

 

Roger

[Peter Cobbold]

I have a new CTM chassis with all new rear shocks, springs and poly bushes.

The problem is that the near side is at zero degrees, with standard brackets but the right hand is about 2 degrees positive. I have checked all parts and cannot find a solution to get the right hand to zero.

Should I fit non standard brackets?

To correct the offside positive camber, measure how much you need to bring inwards the top of the tyre to give zero camber. And measure the radius to the tyre edge. Measure the horizontal distance from the tyre edge (extended down to the hub) to the inner t/a fulcrum. If the tyre top needs to move inwards, say, 22mm and the radius is R and the horizontal distance is H then you need to lower the inner fulcrum by:

22 x ( R/ H ) mm.

In effect you are looking at moving the top of a right angle triangle inwards a defined amount.

That value will be smaller than 22mm, lets guess at 10mm, but may still be greater than the inner bracket can supply. So you then share that10mm between inner and outer brackets, maybe 5 down on the inner and 5 up on the outer. There are several brackets available distinguished by notches. And they can be fiited upside down I think (not sure).

Peter

Edited November 4, 2015 by Peter Cobbold

[jerrytr5]

Roger, do stop making simple things complicated, algebra is not required for setting toe-in.

Now get back to your knitting.

Jerry

[RobinTR6]

I had a similar problem on an earlier TR and used the Buckeye table to adjust the camber. Worked perfectly no problems.

[Peter Cobbold]

Hi Jerry,

your simple statement For each shim the wheel rim will move approx 2.5mm. is actually quite complicated.

 

One needs to sit and think before attacking this area. Compared to replacing the brackets the shims are easy.

 

Roger

 

Roger

Yes, I think of moving a rigid triangle made by the t/a and wheel/tyre rim. For toe-in look down on its from vertically above. We measure:

T radius of tyre edge from hub

Bi lenght of hub to inner bracket , measured from edge of tyre/rim extrapolated to the hub

Bo length of hub to outer bracket " " " "

Removing a say 1.5mm shim from the outer bracket brings the tyre inwards by: 1.5 x ( T / Bo)

" " inner " " 1.5 x ( T / Bi )

As Bi is much longer than Bo a shim removed for the outer bracket has more effect on toe.

 

Peter

[Tom Fremont]

I had this problem on both of my TR250s when fitting new springs, i.e. positive camber and more on the LHS in both cases. I used a combination of brackets including the later TR6 bracket with the most offset to bring them round, where all now have between 1/2 and 1-1/2 degrees negative camber.

 

Having been through this successfully with (2) examples I don't see the need for the adjustable brackets and their additional potential failure modes.

 

Cheers,

Tom

[Graham]

Stuart remind me to add this to the list of 'can you just' jobs when you get BUO

 

ATB Graham

Edited November 4, 2015 by Graham

[Guest ntc]

I had this problem on both of my TR250s when fitting new springs, i.e. positive camber and more on the LHS in both cases. I used a combination of brackets including the later TR6 bracket with the most offset to bring them round, where all now have between 1/2 and 1-1/2 degrees negative camber.

 

Having been through this successfully with (2) examples I don't see the need for the adjustable brackets and their additional potential failure modes.

 

Cheers,

Tom

+1

[RogerH]

Hi Jerry,

sorry if you think I am complicating issues but for the inexperienced car fiddler those brackets and shims need at least a little bit of warning.

 

For my Toe-in issue I removed an outer shim and got the wheels remeasured again and it was well within its tolerance - no algebra at all.

 

Anyway I haven't got any knitting sticks.

 

Roger

[PaulAA]

I had this problem on both of my TR250s when fitting new springs, i.e. positive camber and more on the LHS in both cases. I used a combination of brackets including the later TR6 bracket with the most offset to bring them round, where all now have between 1/2 and 1-1/2 degrees negative camber.

 

Having been through this successfully with (2) examples I don't see the need for the adjustable brackets and their additional potential failure modes.

 

Cheers,

Tom

 

Exactly what I'm relying on, Tom.

 

As I type, my late-model CF is in for new springs, refurbed Armstrong lever arms (+15% stiffer) and new bushes to overcome a very soft tail and nearly 3deg of negative camber both sides. No changes to standard spec, other than swapping to blue poly bushes.

 

Paul

[TriumphV8]

 

For my Toe-in issue I removed an outer shim and got the wheels remeasured again and it was well within its tolerance - no algebra at all.

 

 

For that I have the Gunsons Trakrite and I am happy with/can recommend it.

I am doing several attempts, pushing the car forward and backward

over the Trakrite until the display makes sense.

 

The good thing with Trakrite at home is that between setting and measuring

it is possible to drive a bit around to let the axle settle.

[stuart]

 

For that I have the Gunsons Trakrite and I am happy with/can recommend it.

I am doing several attempts, pushing the car forward and backward

over the Trakrite until the display makes sense.

 

The good thing with Trakrite at home is that between setting and measuring

it is possible to drive a bit around to let the axle settle.

I have the same and an original Dunlop caster/camber gauge for setting.

The driving around between really helps to settle the suspension between which you cant do if fiddling on a ramp.

Stuart.