Setting up/correcting roadwheel geometry on TR5

[TR Mitch]

I've read with interest comments from people who have correctly set up the geometry on their cars (not only TRs) and have a couple of questions for those in the know as I'm interested in getting my local place with the Hunter gear to look at the TR after they've tweaked my Audi and the missus' Boxster.

 

My understanding for the TR5 is that:

 

Rear Set Up

 

The toe in is set using a shim between the trailing arm outer bracket and chassis and this is Moss part number 139363. The numbers in the Bentley & Haynes say the rear should be within 0 to 1/16th inch (0-1.58mm).

 

The camber should be plus 1 degree to minus 1/4 degree (Bentley) or negative 1 degree +/- a half degree (Haynes) but would only need adjusting if the springs had sagged/settled and this is by way of a packing piece between the top of the spring and the rubber collar? Bentley mentions part number HAC104 but I don't see this part in the Moss catalogue. Am I correct in assuming if the springs are relatively new then this does not need "adjustment" and any error may be the construction of the body/chassis/trailing arm interface?

 

Front Set Up

 

Toe in adjusted in the standard way with the track rod ends and the tolerance is between +1/16th and +1/8th inch (1.6-3.2mm) (Bentley) whilst Haynes says between 0 and 1/16th inch.

 

Camber is adjusted with a shim in the wishbone bracket (Moss 139727) and should be biased plus 0.5 deg plus/minus 1 degree (kerb) and 0 degrees plus/minus a half degree (laden) [bentley numbers] or minus 1 degree plus/minus a half degree (Haynes)

 

Castor should be 2.75 degrees plus minus a degree (Bentley) or minus half a degree (Haynes). This is not adjustable on the car.

 

Summary of Settings

 

Rear Toe In : 0 to 1/16th +/- 1/32nd (Bentley & Haynes agree) [trailing arm shim]

 

Rear Camber : -0.25 to +1 degree (Bentley) or -1.0 degree +/- 0.5 degrees [spring shim]

 

Front Toe In : +1/16th to +1/8th (Bentley) or 0 to 1/16th degree [spanner on track rod end]

 

Front Camber : +0.5 degrees +/- 1 degree (Bentley) or -1.0 degree +/- 0.5 degrees (Haynes) [wishbone shim]

 

Front Castor : 2.75 degrees +/- 1 degree (Bentley & Haynes agree) [not adjustable]

 

 

My local Hunter equipped place said Hunter are sending them the TR5 settings but they can also just input the ones I supply. Does anyone have any thoughts on these numbers and any experienced based tips they have for setting up the geometry?

 

I haven't spoken to Moss yet, but do these shims come in different sizes or do you just make up your own?

 

I'd never really thought much about alignment in this level of detail, prior interest was just adjusting the tracking if the car pulled to one side after clonking a pothole or kerb but now I am assuming they will set the rears to run true with the line of the car then the fronts are adjusted to follow the reference provided by the rears thus giving true four wheel alignment?

 

 

 

 

 

[peejay4A]

The method of rear camber adjustment you mention is by adjusting ride height which is what spring spacers will do. Ride height and camber interact on the IRS cars but camber should be adjusted using the trailing arm brackets which have differing geometries based upon the number of notches on the brackets themselves. Different combinations of brackets and their orientations will affect camber. It's a faff. Richard Good sells adjustable T/A brackets that make adjustment easy. Moss sell them too I think. Maybe the best way forward is to get the rear measurements done first then see what you need to adjust.

 

PS, some people dislike the adjustable brackets.

Edited November 5, 2013 by peejay4A

[Kevo_6]

Hi Mitch

I was in a similar position to you earlier this year after a suspension rebuild but in the end the workshop I went too could not help, so I booked my car in with Colin at CTM engineering (http://www.ctmengineering.co.uk/), it did take most of the day.

Maybe too far for you but they do know all about TR chassis’ etc. He did a great job on my four-wheel alignment and the car now drives beautifully.

No connection to them, I am just a happy customer.

 

I do have some spare front and rear shims, if you need them let me know.

Edited November 5, 2013 by Kevo_6

[Tom Fremont]

Hi Mitch,

 

Current springs tend to give positive camber in the rear, necessitating a departure from original protocols to rectify. I used 3-notch brackets on mine to put them right, which in my book is 1/2 to 1 degree negative. Avoid positive camber as it will let the tail come round will little provocation.

 

Richard Good's website used to give the offsets for the factory brackets; there is a recipe to correct virtually every case but if you don't have the patience you can go for his adjustable type. I prefer the simplicity of the originals myself but seem to be in the minority.

[ianc]

You may find that toe-in expressed in inches is not understood by those using modern laser kit. You need to convert to degrees, and it is 20 minutes of arc, or 1/3rd of a degree.

Ian Cornish

[Motorsport Mickey]

Mitch,

 

There is a thread in the Competition forum which may be of interest - Bump Steer , check it out.

 

Mick Richards

[harrytr5]

Hi Mick, your PM says blocked and I can not send you a PM.

Regards Harry.

[Motorsport Mickey]

Harry,

 

You have a PM and an e mail.

 

Mick Richards

[jerrytr5]

You can do all this with a spirit level, string and a few home-made gauges. As previously said, it will take all day which at garage rates may or may not be acceptable to you.

I would at least adjust the camber at home as this is the most time-consuming part especially if you need to change the rear T/A brackets. Spring shims are used to make minor adjustments to ride height primarily but it is an iterative process as height and camber interact. Originals were I believe alloy but varying thickness spring insulators are currently available.

Front and rear shims are one thickness - just vary the number or make up your own.

Negative camber at both ends. 0.5-1.5 degrees.

Toe in at both ends 0 - 1/16".

Don't forget that camber doesn't have to be that accurate - after all suspension moves !

Jerry

[LGFromage]

I've read with interest comments from people who have correctly set up the geometry on their cars (not only TRs) and have a couple of questions for those in the know as I'm interested in getting my local place with the Hunter gear to look at the TR after they've tweaked my Audi and the missus' Boxster.

 

My understanding for the TR5 is that:

 

Rear Set Up

 

The toe in is set using a shim between the trailing arm outer bracket and chassis and this is Moss part number 139363. The numbers in the Bentley & Haynes say the rear should be within 0 to 1/16th inch (0-1.58mm).

 

The camber should be plus 1 degree to minus 1/4 degree (Bentley) or negative 1 degree +/- a half degree (Haynes) but would only need adjusting if the springs had sagged/settled and this is by way of a packing piece between the top of the spring and the rubber collar? Bentley mentions part number HAC104 but I don't see this part in the Moss catalogue. Am I correct in assuming if the springs are relatively new then this does not need "adjustment" and any error may be the construction of the body/chassis/trailing arm interface?

 

Front Set Up

 

Toe in adjusted in the standard way with the track rod ends and the tolerance is between +1/16th and +1/8th inch (1.6-3.2mm) (Bentley) whilst Haynes says between 0 and 1/16th inch.

 

Camber is adjusted with a shim in the wishbone bracket (Moss 139727) and should be biased plus 0.5 deg plus/minus 1 degree (kerb) and 0 degrees plus/minus a half degree (laden) [bentley numbers] or minus 1 degree plus/minus a half degree (Haynes)

 

Castor should be 2.75 degrees plus minus a degree (Bentley) or minus half a degree (Haynes). This is not adjustable on the car.

 

Summary of Settings

 

Rear Toe In : 0 to 1/16th +/- 1/32nd (Bentley & Haynes agree) [trailing arm shim]

 

Rear Camber : -0.25 to +1 degree (Bentley) or -1.0 degree +/- 0.5 degrees [spring shim]

 

Front Toe In : +1/16th to +1/8th (Bentley) or 0 to 1/16th degree [spanner on track rod end]

 

Front Camber : +0.5 degrees +/- 1 degree (Bentley) or -1.0 degree +/- 0.5 degrees (Haynes) [wishbone shim]

 

Front Castor : 2.75 degrees +/- 1 degree (Bentley & Haynes agree) [not adjustable]

 

 

My local Hunter equipped place said Hunter are sending them the TR5 settings but they can also just input the ones I supply. Does anyone have any thoughts on these numbers and any experienced based tips they have for setting up the geometry?

 

I haven't spoken to Moss yet, but do these shims come in different sizes or do you just make up your own?

 

I'd never really thought much about alignment in this level of detail, prior interest was just adjusting the tracking if the car pulled to one side after clonking a pothole or kerb but now I am assuming they will set the rears to run true with the line of the car then the fronts are adjusted to follow the reference provided by the rears thus giving true four wheel alignment?

 

 

 

 

 

I am pretty sure the set up is the same as for a TR4A as the 4 cylinder engine is just as heavy as the 6 and both have the same road springs all round. At least my 4A has as it was fitted with TR5 rear springs just after the 5 was introduced.

 

For the 4A the workshop manual gives the following settings for wheel alignment.

 

Front: Camber 0deg +or- 1/2deg, Caster 2deg 40 min + or - 1/2deg and Toe 0 to 1/16in.

Rear: Camber -1deg + or - 1/2 deg, Toe 0 to 1/16in.

 

My car was set up using the Hunter Hawkeye equipment using their settings as set out below.

 

Front: Camber +0deg 15min to -0deg 15 min, Caster +1deg 54 min to 2deg 54min and Toe -0deg 08 min to +0deg 08 min

Rear: Camber -0deg 30 min to -1 deg 30 min, Toe -0deg 08min to +0deg 08 min.

 

It was possible to achieve the correct settings using standard front and rear shims but, for frosting on the cake, it would be useful to have some shims made using 1swg smaller and 1swg bigger material. However please be advised that alignment using shims is a bit of a pain up the rear and the operator should be fully aware of what he is taking on.

 

Having said that Hunter alignment is really worthwhile as previous attempts at alignment on my car have never produced such a satisfactory result.

 

When setting the rear camber an allowance for the driver should be made. Also for the front wheels it is probably a good idea to set the camber slightly positive. A positive camber makes the wheels want to toe out whilst the caster wants to make them turn in thereby making the steering feel lighter.

 

All the above assumes that your car has the original springs with the original ride height. If not some additional fiddling will be required.

 

Hope you find this useful.

 

Tim

[Steves_TR6]

FWIW Mitch I had my last 6's suspension overhauled by Rees Bros, including the fitting of adjustable TA brackets.

 

They advised on the brackets saying that setting them up was so much easier than changing notched brackets.

However i have heard negative views on the adjustable brackets on here, but nothing quantified.

 

Was very pleased with their work and the resultant handling improvement, although this may have been as much to do with the polybushes fitted at the same time :-)

 

steve

[TR Mitch]

Thank you for the new comments. This job is still pending as the car remains garaged as anywhere within a mile of our house is a foot deep in water!

[Steves_TR6]

A mile!

500m from my house at the moment:-(

 

Might have to buy emergency ramps soon!

Edited February 13, 2014 by SDerbyshire