Ride height change with lowering springs - for reference

[BaulyCars]

Hi everyone, 

I just changed my springs all round and measured each arch height at all four corners before and after.

I thought maybe the change in rideheight information is a useful reference for others (I know there is already a lot of information on the topic so I hope this adds more clarity than confusion!). 

The below gives the free spring lengths, the before and after heights to each wheel arch and the resulting change in rideheight.

Not sure of the spring rates of the springs that were removed, but the new fronts/rears are 650/600lb/in respectively. 

The front shocks were swapped out at the same time (new Avo's, old Spax's which were dead) although I wouldn't expect that to have a great influence on the rideheight.

I also swapped out all the original spring rubbers top and bottom for poly versions. The ones that came off the car were in OK shape so any change in rideheight from those alone is probably not significant I think.

Ignoring the fact that the rideheight is different at each corner (something else to sort out!), the drop in rideheight was approx 47mm front and 37mm rear - rather unexcitingly that's pretty much the same as the change in spring lengths (I was expecting slightly less drop given the high rates of the new springs...). 

Hope its useful!

 

Fronts new and old:

 

Rears new and old:

 

 

Kind Regards

Toby

[RogerH]

Hi Toby,

as well as spring length (unloaded)  there is also the spring rate  Lbs/inch - quite a variety.

 

Roger

[BlueTR3A-5EKT]

Had the new springs been scragged ?   Fully compressed by the maker to ensure they are settled and will not sink once fitted after some weeks of use.  If not what is the ride height after 1000 miles?   
 

https://iecltd.co.uk/catalogues/schnorr-disc-springs/scragging-or-presetting/

Edited June 2, 2023 by BlueTR3A-5EKT

[jerrytr5]

Wow Pete, that's a new term that I must remember and try out at the next meeting: "Have your springs been scragged?"

I'll try it on Roger.

Jerry

[Malbaby]

Those new 600lb plus springs are obviously only for a dedicated race/track car.

[Z320]

Hi Toby,

I was very busy in that issue years ago.

What I had to learn is the free length of the springs says nothing about they length fitted in the car if you don’t know their spring rate.

Shorter, but normally with higher spring rate, the ride high is the same.

I ended with 25 mm lowered original spring, using stronger springs have been a pain to drive.

Their result very easy to calculate: each mm lowered the spring is double lowered on the wheel arch (TR4A-TR6).

The shock absorbers have to be considered on all TR4A-TR6!

Because they have only a short way of travel and the bump stop is inside. Already with a 10 - 15 mm shorter spring you have only they way of travel provided by the bump stop rubber (also a pain).

Modified lower shock absorbers brackets are needed in that case.

On all earlier TRs the way of travel is more obvious to see because of their external bump stop below the spring pan.

I hope that helps

Ciao, Marco

Edited June 10, 2023 by Z320
my original springs have been lowered 25 mm

[RogerH]

11 hours ago, jerrytr5 said:

Wow Pete, that's a new term that I must remember and try out at the next meeting: "Have your springs been scragged?"

I'll try it on Roger.

Jerry

Too late Jerry; I was scragged many years ago.

 

Roger

[BaulyCars]

19 hours ago, RogerH said:

Hi Toby,

as well as spring length (unloaded)  there is also the spring rate  Lbs/inch - quite a variety.

 

Roger

Endless variety it seems and I'm feeling quite scraggy about the whole issue (am I using the word right? ). 

[BaulyCars]

16 hours ago, BlueTR3A-5EKT said:

Had the new springs been scragged ?   Fully compressed by the maker to ensure they are settled and will not sink once fitted after some weeks of use.  If not what is the ride height after 1000 miles?   
 

https://iecltd.co.uk/catalogues/schnorr-disc-springs/scragging-or-presetting/

Not sure and that's new info to me, good to know, but I'll see whether it settles in the coming miles

[BaulyCars]

12 hours ago, Malbaby said:

Those new 600lb plus springs are obviously only for a dedicated race/track car.

It'll be for hard driving on smooth roads, occasional track for fun, but yeah still not really the right spec... Ideally I'd like a 200mm spring at around 400lb.

Although on first drive they're not actually that uncomfortable, surprisingly.  

Edited June 3, 2023 by BaulyCars

[BaulyCars]

@Z320 many thanks - I also thought the ride height wasn't going to drop as much as it did - no doubt other things at work also.

Good to know on the dampers - the Avo's boot covers the bump stop (assuming there is one in there - wish I'd had a look now before I fitted them, and measure their before and after length....)

Does anyone make the modified lower damper bracket (or perhaps you've a picture of one?) - would be interested to look at that. 

Now when I look at it there's still actually more rideheight than I'd like... largely as its on a 195/65 tyre so there is more arch gap than with a classic tyre.

Yours looks spot on, super looking.

 

Edited June 3, 2023 by BaulyCars

[BlueTR3A-5EKT]

There is a trick to get the front  lower   Fit the front lower wishbones upside down to lower the suspension by about 3/4”   That does not call for shocker lower mount bracket modification as you are raising the axle pin.   Top wishbone will need to move upwards and inwards too.  

[BaulyCars]

Thanks, Peter, something I’ll have a go at - I’d seen a couple references to this but wasn’t sure if it was an accidental thing. 

Any downsides?

Surprised someone hasn’t tried to make a drop spindle (I think Canley did one for the GT6) 

Edited June 3, 2023 by BaulyCars

[Z320]

6 hours ago, BaulyCars said:

@Z320 many thanks - I also thought the ride height wasn't going to drop as much as it did - no doubt other things at work also.

Good to know on the dampers - the Avo's boot covers the bump stop (assuming there is one in there - wish I'd had a look now before I fitted them, and measure their before and after length....)

Does anyone make the modified lower damper bracket (or perhaps you've a picture of one?) - would be interested to look at that. 

Now when I look at it there's still actually more rideheight than I'd like... largely as its on a 195/65 tyre so there is more arch gap than with a classic tyre.

Yours looks spot on, super looking.

 

Hi Toby,

the correct length of the shock absorbers I posted a short time ago - but I don’t remember where?

Modified shock absorber brackets I found nowhere to buy, this is why I made them my own.

See the attached photos 

If I remember correctly I made them 18 mm lowered, you have to find out yourself how much you need, please.

Ciao, Marco 

[Z320]

Here it is

[BlueTR3A-5EKT]

1 hour ago, BaulyCars said:

Thanks, Peter, something I’ll have a go at - I’d seen a couple references to this but wasn’t sure if it was an accidental thing. 

Any downsides?

Surprised someone hasn’t tried to make a drop spindle (I think Canley did one for the GT6) 

The stud fixing at the inner end could be an issue.  Tap right through I guess to let the stud be fixed   From either side 

Edited June 3, 2023 by BlueTR3A-5EKT

[Chris59]

Hello guys, what about "standard" height (and stiffness) front springs, for a 71 TR6 ?

I'm after this kind of springs, but don't know where to find the right ones, as I don't want to fit "sagging fast" poor repros.

 

[BaulyCars]

On 6/3/2023 at 10:22 PM, Z320 said:

Hi Toby,

the correct length of the shock absorbers I posted a short time ago - but I don’t remember where?

Modified shock absorber brackets I found nowhere to buy, this is why I made them my own.

See the attached photos 

If I remember correctly I made them 18 mm lowered, you have to find out yourself how much you need, please.

Ciao, Marco 

Very nice. 

Did you think about supporting a coilover off those brackets... Makes me think of that when I see these.  

[Z320]

no

[BlueTR3A-5EKT]

Probably tear the 4 studs out the lower spring pan if you expect them to support the coil spring as well as the shocker.  

[Malbaby]

Adjustable coil over combinations are a great idea, but in our later TR's, there is not enough available height to effectively fit them, even with Marco's lowered/modified shock brackets.

The shock towers would have to be modified...[higher].

[BaulyCars]

I found a couple references of TR6 coilovers, seems a few have thought about it before. Certainly a custom lower bracket and/or lower spring pan re-design needed and a custom bracket/modification up top also (the pic below appears to be on a Ratco chassis or similar).

The lower pan/brackets is probably the easier one to design/fab, the upper shock towers would be the challenge, to not have to modify the factory shock tower somehow.

Maybe some sort of 'cup' arrangement that the coilover rod end bolts to, then the cup goes up into the shock tower with the outer edge of the cup bearing onto the same location the springs originally bear onto?

The cup could still be held in place using the original damper top bolt and bush arrangement since the damper rebound forces still come out through the top bolt.  

Poor sketch attached if that makes any sense...!

 

Kind Regards

Toby

  

Edited June 5, 2023 by BaulyCars

[roy53]

i do think that you would have a more accurate reading of heights if taken from the chassis to ground. Wings can vary.

Roy

[nickw71]

On 6/4/2023 at 7:13 PM, Chris59 said:

Hello guys, what about "standard" height (and stiffness) front springs, for a 71 TR6 ?

I'm after this kind of springs, but don't know where to find the right ones, as I don't want to fit "sagging fast" poor repros.

 

I'd like to ask the same question. After 14 years of driving the car with uprated springs (Triumph Tune 420lbs rears and 390lbs judging by the colours spots) and getting sick of the harsh ride on the terrible Bucks roads I'm going to change back to standard springs or slightly uprated. The front ride height is also very much lowered on my car with the springs having a compressed length of around 6" resulting in routinely bottoming out on the steering rack mounting straps and front cross member.  

I'm also changing over from yellow road/race poly bushes to SuperFlex all round to hopefully reduce harshness. 

I have Koni's all round with type 2 (CTM) rear conversion with the shocks would back. 

Question 1 - do I go for "standard" spring set (354lbs/312lbs) in order to achieve a more compliant ride and are the silicone chrome versions from a well-known supplier worth the extra? Where are the best ones to be found? 

Question 2 - Will standard springs work well with my Konis? 

Many thanks 

Nick 

 

[Z320]

Hi Nick,

if your front height is much lowered and you dit not bother the free way of travel of your shock absorbers

you very likely drive / bound on the internal rubbers / bump stop of your shock absorbers.

That's indeed a pain.

In my opinion, if you drive alway with your look strongly on the road 50 - 100 m ahead,

avoiding to drive across / throught everything - something is wrong...

Ciao, Marco