Front suspension height

[Waldi]

7 hours ago, Z320 said:

Nearly, 1 mm on the spring are 2 mm on the wheel arch,

1/2“ longer with original spring rate is 1“ on the wheel arch.

Big mistake to give any old original part to the scrap!

Hi Marco,

a factor 1.5 is what I measured on my TR6 (IRS) rear springs. A friend had the same experience. Maybe front is a factor 2?

Waldi

[Z320]

Yes, on the front.

10 turns with my M12x1.75 compressor tool is 35 mm on the wing

[andyhall]

Hi,

I used this https://www.thespringstore.com/spring-calculator.html as tool to help, but at 10.25" free length that does seem high would have thought 8.5-9"

also found this https://www.tr-register.co.uk/forums/index.php?/topic/60959-tr6-spring-heights/

 

Andy

 

 

[AJAS]

Front springs from trgb, rear springs stickered as Rimmers. The part numbers seem common between these and moss

[Bfg]

Tony, If I understand correctly you haven't yet driven the car with those springs fitted.  In case it's of interest this was my TR4A ( Katie ) after I'd rebuilt the suspension . . .

 

^ and as you can see it was sitting very high ..despite my also bumping up and down on the front wing.  The static spring length was 10-1/4".

This however is what it looked like after the car was driven . . .

^  Better.  After just a hundred miles it is lower than when first lowered to the ground, but it is still sitting high.  Having no bumpers doesn't help its static sitting-high look. And again the modern 165/80 tyres are lower profile than the originals fitted to this model, so the wheel-arch to tyre gaps are greater.   

I'd also point out that a more representative measurement might be ground clearance.  Katie's  under chassis ground clearance at the front jacking place (behind the front wheels) is 6.5" ..which is just 1/2" more than specification, but the wheel-arch to tyre clearance is still an inch more that I would have thought 'normal'.  Part of this is that front-LHS wing and wheel-arch is higher than the RHS by almost 3/8" . . .

     

^ This side of the car has a more even gap under the front and rear wheel-arches.  Those gaps are still a little large, but only by 1/2" at the front (..which corresponds to chassis ground clearance).  As it happens I rather like the bumper-less slightly-high stance, and somewhat under-dressed-look for my car, but that's by and by.

Certainly the springs that were fitted before, I had the chassis changed, rode much lower.  Part of that was in the rubber isolation collars which had, over the years, each compressed down to less than 2mm thick.   But equally I believe the springs were softer too than modern replacements (of standard spec).  I suspect the new ones have more chrome in the metal's compound to make them springier and less prone to sag after a few years.  

It seems inconceivable to me that the TR4A, TR5, TR250, and TR6 should each have the same 'standard specification' because the both the vehicle weight and the weight-distribution of each model is different.  So what TRGB ..or anyone else, considers 'standard' ..I take a with a silver-seller of salt. !

 

I might add that I also went on to alter the suspension on the rear right-hand-side, to correct its tracking and camber. The latter slightly raised its ride height, which in turn has an effect (because it is carry more weight when parked) on the front wheel-arch clearance . . .

^ The difference is subtle ..to how she was sitting in my second photo (above),  but now the front and rear wheel-arch to tyre gaps are even. The rear has increased by 1/4" and the front has dropped by a similar amount.  It's still high compared to the white TR6 parked next to it, but as I say I'm not after a low n' lean look, and the upward sweep of the TR4's chrome trim, besides the headlamp brows, and also the bonnet bulge over the carbs, each contribute to Michelotti's tall and narrow style anyway.

In conclusion, and as other have suggested.. drive the car and give the suspension a little time to settle - if only to compress into the isolation collars top & bottom (poly may take much longer than the original rubber types). But then also check the chassis' ground clearance as your datum dimension.  And then once you've adjusted your rear suspension settings, you might notice further change to the wheel-arch clearance at the front tyre.

Hope that helps,  and perhaps even reassures you a little.  

Best regards, Pete     

 

p.s.  once the car has been driven a couple of hundred miles to settle the suspension - then do remember to check the camber angles at each wheel, as of course ride height and camber angles are to a degree co-dependent. 

 

 

 

Edited March 29, 2023 by Bfg

[Z320]

Hi Tony,

to get the car real down and to a modern look I did what Jochem already told you:

I gave the original coil springs to a special company to compress them 25 mm!

The spring rate is still the same, but I had to lover the shock absorber brackets 20 mm to get the shock absorbers work again.

My tyres are 185/80R15, they are wider and bigger than 165/80R15, filling the wheel arche better

I hope this helps.

Ciao, Marco 

[lee]

I’ve always struggled to get a TR to sit lower. 
Just had fitted slightly stiffer lowered springs and the car sits at factory height. Mad  

 

[Z320]

lowered but stiffer is about the same height as original.

[AJAS]

Thanks again for input, especially Pete with his comprehensive thoughts. Below is a picture of the car as bought - low at the front and high at the back......Altho this came with a comprehensive file, there is no reference to the front springs being replaced so don't know whether they were standard or lowered. Note the front trunnion bolt was seized solid, so may have had an impact on the height

 

[Bfg]

^ looks to me as if your car's rear suspension springs have been 'uprated' to help prevent take-off attitude ..and the exhaust dragging, under brutish acceleration, &/or when loaded for touring.  Stiffer rear springs tends to pitch the car's nose down when the car is parked, in a static and unladen condition. This is evident in your photo by the sill not being parallel to the ground, as I believe it was designed to be.

Pete

[AJAS]

Remover the offside rear trailing arm and there is a near new spring with a Rimmer sticker - checking the part number on their website, it says that this is a standard rear spring

[Bfg]

^ This is what my own car's wheel arch clearance looked like when I bought her.  She was particularly low on the driver's side.

^ And this is what she looked like after the chassis change, after being driven 120 miles home. (NB. although they look different because of the wire wheels and white walls the prior owner fitted, the tyres are the same size and profile in each photo) 

..but sitting too high, and a little higher at the back but otherwise pretty even gaps on both sides (actually at that time the LHS of the car  was now sitting just a tad higher).  The replacement rear springs now fitted were the same length (11-1/2" free length) as the old springs, and their compression - measured with just 24kg on them was 1/4" (same for both sets), so I concluded ; the replacement and the old springs were of the same rating < here >.  

Their mechanic had fitted new 7mm thick poly isolation collars top and bottom.  Changing back to the original isolation (4 to 5mm thick) collars lowered the ride height by the predicted 1/4". 

But the rear wheel's camber was now positive (wheel leaning out at the top, whereas it should be leaning in by 2-degrees)  so I researched what the effect would be in changing (swapping-out) the semi-trailing brackets.  I found information (from an American website) very useful but flawed.  Reproducing the suspension geometry in a 3d computer program, I formulated a predictive chart < here >.  Using this I was able to correct the rear wheel's camber and at the same time lower the back of the car.  I also changed again the isolation collars to 3mm thick ones (off the front suspension) ..and yes they do just about fit - to lower the rear's ride height by a further 1/4".

I had a lot of other jobs to do on the car.. and so it took until August last year before I was able to properly drive her any distance - to settle its suspension. Thankfully the effort was worthwhile. . .

^ the rear wheel-arch to tyre clearance is not far off, or from where it now is (..which I'm happy with), but I've subsequently rebuilt the front suspension ..as on both sides the lower-outer trunnion pins were seized with rust (..which does not effect ride height).  While doing so I swapped springs for the same length but slightly softer spring, so she's now sitting level, as you've seen in my previous post. 

Bottom line ; after the chassis swap - this car's rear suspension's camber angle needed correcting from positive (wheel leaning out) to negative. I did this by changing (swapping-out) the trailing arm brackets in accordance with the chart I'd formulated.  Along with the spring's length and stiffness, the choice and orientation of those semi-trailing arm brackets, together with the thickness of isolation collars (top and bottom) directly effect ride height.  As said before the rear ride height does have an effect on the front, although probably that's as much a matter of visually equalising those gaps.  

Again I hope these experiences help,

Pete

 

 

Edited March 29, 2023 by Bfg

[AJAS]

Thanks Pete. Looks like that took some thinking through!

The brackets fitted are 1 notch outer and 2 notches inner, both with 2 shims. The spring rubbers are much thicker than on the front, but haven't measured them yet.

I have a couple of weeks break in proceedings, but will be back ready to put in four wheels to see what I have and decide where to go from there.

Thanks to all contributors who have taken an interest in this!

[rcreweread]

I think one of the main issues here is "words" and in particular the term "standard" - I think I'm right is saying that Standard ( pardon the pun!)Triumph changed ( uprated if you like) the rear springs 3 times from when they first appeared on the TR4A to the last type on the TR6. If the standard spring at the time for a 4A was "x", then the next time they changed the spring rate, that became the standard then, and when they did the last upgrade on the TR6, that became the standard after that.

Given that I wouldn't be surprised if most, if not all, the springs sold by the TR Suppliers come from the same manufacturer/supplier, I imagine that they have adopted the last TR6 uprated spring as the "standard" - this has a higher spring rate than that fitted to many earlier cars, and if those original springs haven't previously been changed, then your new "standard" springs won't be the same, hence they will have an impact on ride height and ride.

I'm afraid I don't have all the technical stull about spring rates, heights, number and thickness of coils to hand, but it seems to be an increasing area of concern here on the forum - wouldn't it be great if someone with the detailed knowledge could produce a definitive schedule of what is currently available and compare with original specs and then cross reference that with availability - if that throws up serious gaps in the available springs, then that could be an initiative for the SDF or alternatively an issue to be raised by the PQI ( parts quality initiative) team.

Unfortunately I don't haver the info and skills sets to volunteer myself, so don't suggest it!

Cheers Rich

PS Maybe something already exists, in which case we need to publicise it!

[Bfg]

Tony, just to clarify ; 

• the shims under the rear  semi-trailing arm to chassis brackets only adjust the tracking of the rear wheel (LHS and RHS arms are individually adjusted by the brackets on that side.)   Those shims have no discernible effect on ride height
• Whereas the number of shims under the front  suspension's lower wishbones brackets adjust the camber  &/or the castor  of the front wheel.  They do effect ride height but only by a very small  amount, insomuch as extra shims swings the lower wishbones outwards, so the wheel's camber becomes more negative. As the wheel spindle is tilted, so the ride height is lowered slightly (..although hardly enough to be worth thinking about).

Adjusting the steering-rack's track-rod-end, on just one side, effects the tracking  of both front  wheels. So it is correct to adjust the track-rod-ends on either side (in or out by exactly the same amount) otherwise the steering column will be turned when driving straight ahead and the steering wheel will not be level.  

However, sometimes an owner will find that the indicator switch will cancel earlier on one turn than on the other. This is because the track-rod-ends have not been adjusted evenly and so the steering column is turned. The wheel has then been leveled on the steering-column's spline, but the column's indicator-switch's cam is not level, so it cancels the switch on one side's turn at a different angle to the other. 

 

  16 hours ago, AJAS said:

put the car on four wheels to see what I have and decide where to go from there.

That's the way to go.    Only after settling the car into its suspension, can you reasonably assess what fine adjustments might yet be required. 

Pete     

     

 

Edited March 30, 2023 by Bfg

[Bfg]

Tony, just to clarify ; 

• the shims under the rear  semi-trailing arm to chassis brackets only adjust the tracking of the rear wheel (LHS and RHS arms are individually adjusted by the brackets on that side.)   Those shims have no discernible effect on ride height
• Whereas the number of shims under the front  suspension's lower wishbones brackets adjust the camber and the castor  of the front wheel.  They do effect ride height but only by a very small  amount, insomuch as extra shims swings the lower wishbones outwards, so the wheel's camber becomes more negative. As the wheel spindle is tilted, so the ride height is lowered slightly (..although hardly enough to be worth thinking about).

Adjusting the steering-rack's track-rod-end, on just one side, effects the tracking  of both front wheels. So it is correct to adjust the track-rod-ends on either side (in or out by exactly the same amount) otherwise the steering column will be turned when driving straight ahead and the steering wheel will not be level.  

However, sometimes an owner will find that the indicator switch will cancel earlier on one turn than on the other. This is because the track-rod-ends have not been adjusted evenly and so the steering column is turned. The wheel has then been leveled on the steering-column's spline, but the column's indicator-switch's cam is not level, so it cancels the switch on one side's turn at a different angle to the other. 

 

14 hours ago, AJAS said:

put the car on four wheels to see what I have and decide where to go from there.

That's the way to go.    Only after settling the car into its suspension, can you reasonably assess what fine adjustments might yet be required. 

Pete     

 

 

Edited March 30, 2023 by Bfg

[Bfg]

14 hours ago, rcreweread said:

it seems to be an increasing area of concern here on the forum - wouldn't it be great if someone with the detailed knowledge could produce a definitive schedule of what is currently available and compare with original specs and then cross reference that with availability - if that throws up serious gaps in the available springs, then that could be an initiative for the SDF or alternatively an issue to be raised by the PQI ( parts quality initiative) team.

While I agree with most everything you've said, I suspect that there is little motivation for anyone to do it (likewise I do not have the resources) ...but do come back Roger and all will be forgiven.

I suspect my car's suspension springs were replaced because I specifically asked the chassis replacer to at-the-same-time correct the car's lop-sided suspension (which was low on the driver's side front wheel).  They might have assumed, as many of us would, that the spring had gone soft over the years and so simply swapped them out (as a pair) for replacements (which I'm sure were very good 'standard' TR6 ones ..and so too stiff for the lighter nose weight of the TR4A).  Whereas from what I've seen - as I did get the old components back, and then compared them to what was newly fitted - all the garage needed to do was to replace the old / perished and squashed isolation collars.  Which they did as well, but again changed the spec from what it was.

I may be wrong but I'd guess many home restorers swap out their car's suspension springs for new ones because they're thinking "the old ones are old and so must be worn out".  Personally I think 9/10 of those are wasting their money and end up replacing one problems for another.   If I were asked now (in light of my own experience) I'd recommend anyone - treat the diagnostics of their car's suspension in the same way as they might the engine. . .

• Get it running and settled in.
• Then assess it. 
• Only change what has obviously failed or is failing when you rebuild it.  Replacing like for like. measuring and comparing the new with the old to ensure that's the case.
• Get it running and settled in.
• Then reassess it. 
• And only change one thing at a time, with adjustments made by small degrees.
• Then use it for a while ..to see if it suits your own particular needs, load conditions and driving style, and local road & traffic conditions,
• Only once everything is right, working well and to specification, might you consider upgrades.

if one don't follow such a methodical path, and instead chase 'upgrade' specifications like stiffer springs, different dampers and anti-roll bars - then it would be like going for bigger bores and swapping the engine's camshaft for improved power, when really all that was needed for a sweet and reliable ride was to rebuild a worn distributor.

Just one man's opinion of course,

Pete

 

[DRD]

16 hours ago, rcreweread said:

I think one of the main issues here is "words" and in particular the term "standard" - I think I'm right is saying that Standard ( pardon the pun!)Triumph changed ( uprated if you like) the rear springs 3 times from when they first appeared on the TR4A to the last type on the TR6. If the standard spring at the time for a 4A was "x", then the next time they changed the spring rate, that became the standard then, and when they did the last upgrade on the TR6, that became the standard after that.

Given that I wouldn't be surprised if most, if not all, the springs sold by the TR Suppliers come from the same manufacturer/supplier, I imagine that they have adopted the last TR6 uprated spring as the "standard" - this has a higher spring rate than that fitted to many earlier cars, and if those original springs haven't previously been changed, then your new "standard" springs won't be the same, hence they will have an impact on ride height and ride.

I'm afraid I don't have all the technical stull about spring rates, heights, number and thickness of coils to hand, but it seems to be an increasing area of concern here on the forum - wouldn't it be great if someone with the detailed knowledge could produce a definitive schedule of what is currently available and compare with original specs and then cross reference that with availability - if that throws up serious gaps in the available springs, then that could be an initiative for the SDF or alternatively an issue to be raised by the PQI ( parts quality initiative) team.

Unfortunately I don't haver the info and skills sets to volunteer myself, so don't suggest it!

Cheers Rich

PS Maybe something already exists, in which case we need to publicise it!

This is something I pulled together a while ago using info from various sources from the web when I was working out what options were available. I can't guarantee its completely correct though. Also I found that quite a few of these parts weren't always easily available.

[Bfg]

Brilliant DRD    Thank you for sharing that compilation of road-spring data for, I assume, the TR6.

Would you also have happen to have beavered away the data regarding what the standard springs were, as quoted by Stan-Triumph for each model - the TR4 (fronts only), the TR4A-leaf-spring (fronts only), TR4A-IRS, TR5, TR250 and TR6 (..in its various model guises and for UK and overseas specs) at the time each were offered onto the market and then subsequently when their specification were amended ? 

cheers

Pete

[Malbaby]

Tony...as a matter of interest what ground clearance do you have to the chassis at the front?

 

[AJAS]

Hi. I did measure both sides after I got the car to check it was level, but can't remember what it was. It's currently on axle stands doing the rear suspension, although I don't have time to do that for a couple of weeks. Will check when it's back on terra firma.....