Follow WSM Suspension and Steering data for suspension set up or not?

[Martin V]

I've been looking at 4.119 WSM (unladen )for my late GT6 1973 non-rotoflex >KF20000 data and looking to get something that is "right" wrt alignment and suspension.

Problem: My steering was vague and steering misaligned. This turned out to be due to both wheels being toe out (thanks PO) and NS considerably more when steering wheel was straight. The cambers also looked considerably +ve and not even.

Alignment

We used Trackrite to adjust to a toe in of about 0.25deg per side (I calculated the WSM target 1/6-1/8 from various tables for std whee//tyre size). Steering wheel now more or less straight and felt better on short 2 mile run but need proper road test on straight A road when the monsoons end.

Not checked rear toe yet but I understand the shims are available to give me straight or minor toe in if wheels are toe out.

Depending on the proper test drive I will settle for small toe in F&R or zero toe in but allowing for some splaying of front with a small toe in makes sense to me.

Camber

Measured with Gunson and nice wheel rim alignment tool off ebay ("Camber Bar - New adjustable" thatI'd highly recommend), I found the following:

Front DS +2.75deg and NS +1deg:

Qn: What to aim for - With modern radials do I try to increase NS with shims or should I even try to balance the camber L/R and remove refit steering wheel straight as start point? I think PO may have had it not far off WSM for camber but then not fitted steering wheel correctly? OR should I even aim for nearer 0deg camber as positive does not make sense to me !

Qn: Can anyone explain why positive would be good for front and whether that was specific to Radials ?

Camber Rear +1.75deg each side : *late 1973 GT6 non rotoflex* target WSM is -1 (+/-1)

Qn: For Rear, I'm wondering if something like the PO tightening the eye bolt/damper bolts up when the car was off the ground might be causing the springs/bushes to be working against the car and causing the positive camber? PO did apparently fit a new spring on the rebuild and I'd have hoped he fitted correct spec.

Qn: Anything else that could be adjusted/checked to give me 0 to -1 camber on rear?

 

As ever much appreciate any guidance.

 

 

Overall I also plan to take Castor measurements and then consider the complete picture with Camber/Toe knowing that increasing toe in reduces positive camber. I did small experiment to see if half turn on each side opposite directions on rid ends made much difference on camber and was clear to see the impact so I know that whatever I do with Camber/Alignment I need to check and compensate.

 

[Pete Lewis]

just check the geometry specification data you used  is unladen or as many are 150lb on each seat to set the static ride height 

some gt6 spec is unladen but if not you need to get rent  a crowed  round or a bags of sand 

especially important to get the rear toe correct to stop bunny hops on pot holes /rear wheel steering   etc.

pleased you have some basic gear to check with 

Pete

[Martin V]

https://tecb.eu/onewebmedia/Triumph Vitesse GT6 workshop manual.pdf

P 259 top table is for the unladen and shows the models including my own late Gt6

Suspension& alignment data WSM P259.pdf

[Martin V]

Looking further afield at suggested real world user comments UK/ US, it seems that Front Camber is the one that it is probably not sensible to follow the original 2-3deg +ve camber specification with today's tyres. I think I'll try work towards 0 to -1 deg unladen. If I can get to that it would be good, using shims of course. Need to then work out the rear camber (unladen, after a short drive) as +ve on the back is not good but that might just need the bush fixings to be loosened off and allowed to settle under the cars own weight so I will try that and see where it takes me. Again zero to -1 unladen would be my aim.

[Pete Lewis]

simplest way to change the rear camber is to add a spring lowering block on top of the diff

cheap and very effective

Pete

[Martin V]

23 hours ago, Pete Lewis said:

simplest way to change the rear camber is to add a spring lowering block on top of the diff

cheap and very effective

Pete

Thanks Pete, where might I source such a block and is it simple enough to do?

[Pete Lewis]

canley classics and others  they come in 1/2" 3/4" and 1"   heres a couple of suppliers 

 Alloy Diff Spacers : Canley Classics

James Paddock Limited - Triumph Stag, Spitfire, TR6, TR7, GT6, Vitesse, Herald Parts and Spares Specialists. REAR SPRING LOWERING BLOCK ALLOY 1/2 INCH SPIT MKIV/1500/GT6 DRIVESHAFT(SSP1)

the deeper ones will probably need longer studs in the diff and then they fouls the tin cover  i used a !" and made a rubber cover from a mud flap 

cant advise which to use as we had a courier spring fitted ,buy 2 thin ones and play but that adds costs 

Pete

Edited November 17, 2023 by Pete Lewis

[Martin V]

2 hours ago, Pete Lewis said:

canley classics and others  they come in 1/2" 3/4" and 1"   heres a couple of suppliers 

 Alloy Diff Spacers : Canley Classics

James Paddock Limited - Triumph Stag, Spitfire, TR6, TR7, GT6, Vitesse, Herald Parts and Spares Specialists. REAR SPRING LOWERING BLOCK ALLOY 1/2 INCH SPIT MKIV/1500/GT6 DRIVESHAFT(SSP1)

the deeper ones will probably need longer studs in the diff and then they fouls the tin cover  i used a !" and made a rubber cover from a mud flap 

cant advise which to use as we had a courier spring fitted ,buy 2 thin ones and play but that adds costs 

Pete

Thanks Pete, also my two preferred suppliers. I'll look into how this would be done and see when I might try it.

[Pete Lewis]

you do need to remove the spring to fit a spacer so need enough room to extricate the unit out the side of the car 

many have done this an find the garage wall gets in the way  ha !  

if you remove all the studs and lift enough to drop a spacer in thats also possible 

Pete

[Martin V]

On 17/11/2023 at 14:31, Pete Lewis said:

you do need to remove the spring to fit a spacer so need enough room to extricate the unit out the side of the car 

many have done this an find the garage wall gets in the way  ha !  

if you remove all the studs and lift enough to drop a spacer in thats also possible 

Pete

I have one on order, Thanks again Pete. Dave at Canley's also suggested this 1/2" space could be fitted by undoing and removing the studs. Will be giving it a try at some point over winter.

Edited November 24, 2023 by Martin V

[Pete Lewis]

yes let the spring rise and remove the studs   they are 3/8" and unf threaded   nothing special 

Pete

[Waynebaby]

From my experience getting the holes in the spring to line up with the holes in the spacer to line up with the holes in the differential can be a bit of a nightmare! Take your time making sure the studs are going cleanly into the holes in the differential, as it's quite easy to strip a thread in the casing. Ask me how I know!! 

Wayne

 

[Pete Lewis]

you could leave the rear set of studs in place   and slot the  rear packer holes 

the packer doesnt need the studs for location the packer is located in the diff case by the spring location 

pete

[Martin V]

22 hours ago, Pete Lewis said:

you could leave the rear set of studs in place   and slot the  rear packer holes 

the packer doesnt need the studs for location the packer is located in the diff case by the spring location 

pete

You mean, just to check my understanding, change two of the holes on my new spacer to open slots to the rear edge of the new spacer and just push that rear side onto the in place rear studs then refit front studs?

Sounds a great idea if that’s understood correctly. I have friends who could probably do that very easily for me.

thanks both for your comments

[Pete Lewis]

thats the idea     4 studs on a swing spring box   6 studs on a fixed spring 

so yes leave   2 stud in and slot the packer holes to slide it under the spring box on your swinger.

drop the spring box back and fit the other two studs  then  torque the nuts 

Pete

[Martin V]

On 26/11/2023 at 10:41, Pete Lewis said:

thats the idea     4 studs on a swing spring box   6 studs on a fixed spring 

so yes leave   2 stud in and slot the packer holes to slide it under the spring box on your swinger.

drop the spring box back and fit the other two studs  then  torque the nuts 

Pete

All fitted nicely at the weekend, thanks Pete. I got the rear on axle stands, undid the nylocs (4 on my late GT6), removed the two front studs, lifted very slightly the wheel verticals on both sides with jacks and the from near side managed to insert my arm to the differential gap and slide my slotted half inch spacer into the gap.

Points of note for anyone trying the same job;

Prepare the studs carefully before trying the job : I spent couple of hours the day before removing each stud individually, cleaning the thread/loosening seized nylocs etc. this enabled me to ensure I could get enough minimal thread visible after inserting the spacer. After inserting the spacer I pre-fitted the nyloc enough to get the nylon onto the end of the stud. Then used that to reinsert the studs. I did this one by one, always having min 2 in place. The studs are OK for half inch spacers but would need longer studs for larger spacer.

You may also need a little filing of the side edges (front and back) to allow the spacer to fit enough into the trough in the top of differential.

I slotted the rear bolt holes which enabled me to leave rear studs in place which held spring clamp aligned (thanks for the tip Pete). I needed a small nudge of one stud to reinsert through lower spring clamp plate but otherwise went back perfectly.

Half inch spacer removed 1 deg positive camber both sides rear leaving me at 0 deg (both unladen).

Thanks for you help, I had the job done surprisingly easily/quickly and also now have a sealant sealed cover panel and new nylocs and cover panel screws so it looks grand!

[Pete Lewis]

nice to know when a job comes together with smile 

great  when a legit short cut works correctly 

Pete

Edited December 11, 2023 by Pete Lewis