Adjusting ride height

Adjusting ride height

Author
Discussion

wuckfitracing

Original Poster:

990 posts

142 months

Sunday 23rd April 2017
quotequote all
My car is up on my ramp and whilst Its there im going to raise the ride height as when touring some of Scotlands roads last year it decided it wanted to file down the rear anti roll bar on the tarmac every now and then. Ive measured the rear and its 135mm from floor to the chassis outrigger corner plates. The front is also same !
Can anyone confirm it should be 150mm at rear and 140mm at front, give or take 5mm. Im off to Spa classic in May and dont fancy grounding on the ferry ramp ( The missus MX5 did last year).

bobfather

11,171 posts

254 months

Sunday 23rd April 2017
quotequote all
In simple terms the suspension set-up uses unequal length wishbones so ride height changes will affect the way the alignment works when cornering.

The benefit of unequal length wishbones is that the camber angle can alter as the suspension loads and unloads. For this reason the suspension should be set so that the lower wishbones are horizontal at rest. This allows the camber to change in one direction as it loads and the other direction when unloaded. The ride height you mention should be about right. I would suggest you are bottoming out because your rear springs are old or under rated and/or your dampers are loosing their ability to resist rapid movement.

phillpot

17,105 posts

182 months

Sunday 23rd April 2017
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bobfather said:
I I would suggest you are bottoming out because..........
................the scenery is wonderful in Scotland but the roads are shyte wink

SILICONEKID345HP

14,997 posts

230 months

Sunday 23rd April 2017
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What are the consequences of running lsrger diameter tyres ?

bobfather

11,171 posts

254 months

Sunday 23rd April 2017
quotequote all
phillpot said:
................the scenery is wonderful in Scotland but the roads are shyte wink
Scotland is my favourite TVR driving country, I've done loads of rough roads there but I will say that Scotland also has some of the finest road surfaces. You need to get on Hardnott Pass if you want rough roads. I just use stiffer suspension, changing the ride height spoils the poise of the car so what's the point in doing it if you're trying to enjoy twisty undulating roads

wuckfitracing

Original Poster:

990 posts

142 months

Sunday 23rd April 2017
quotequote all
Sorry should have mentioned. About 2 years old Gas Gold Pros. Less than 2000 miles on them. They work very well and have 400lb springs on the rear (if I remember correctly). Full geo set up by a company in Sheffield. Just too low. Hence my question does anyone know what is normal. Oh and standard size wheels and tyres 15" on front and 16" on rear.

ClassicChimaera

12,424 posts

148 months

Sunday 23rd April 2017
quotequote all
Excellent post from Bob there. Mines more like 150-155 measuring up to corner of chassis points to get a level lower wishbone. And I like the point about rapid movement too.
The consequences of larger dia tyre's is higher ride height and also a loss of arch space.
My rears are I think about 20 mm larger in dia so 10 mm ride height and also 10 mm loss of arch space, or in my case actually fills the arch and looks gooood. I run mine as high as I can get away with, for a number of reasons but mainly because it works better imho.

Peter mentioned mine looked lower than his when I did my dif, I've raised it since to very good effect. It's a few mm or cm rather than inches.

ClassicChimaera

12,424 posts

148 months

Sunday 23rd April 2017
quotequote all
Going by the corners of chassis I thought standard it's about 140-150 F to 150-160 R
But I could be wrong. thumbup

bobfather

11,171 posts

254 months

Sunday 23rd April 2017
quotequote all
For info I'm sitting at 155/145mm to the corner plates. I do have the factory five stud conversion so my rolling diameters are slightly different to the original tyre spec though I doubt they're different enough to make any real difference. The camber shift that occurs due to loading and unloading is progressive so +/-5mm in ride height shouldn't be an issue

wuckfitracing

Original Poster:

990 posts

142 months

Sunday 23rd April 2017
quotequote all
Thanks chaps, as I thought 135mm front and rear is too low.

SILICONEKID345HP

14,997 posts

230 months

Sunday 23rd April 2017
quotequote all
Im running. 205 50 16
And 235 45 17

Does this mean I need to lower the ride height to get the wishbone level ?

ClassicChimaera

12,424 posts

148 months

Sunday 23rd April 2017
quotequote all
The position of your wishbone won't change by raising tyre dia, the car will just naturally sit higher because of the tyre. This in theory allows you to drop ride height as you have more ground clearance but you'll be constrained by the less room inside wheel arch.
Sorry I was incorrect about the 20 mm,,, that's the fronts hehe
Check a tyre size calculator to determine how much higher your car sits on its tyre's and go from there, it's a few mm not inches, doesn't make a huge difference and you don't need to effect ride height.

ClassicChimaera

12,424 posts

148 months

Sunday 23rd April 2017
quotequote all
Dropping pressures to cold 20's will lower ride height by a few mm but then go up again when they get hot and read 30 psi biggrin it's all bks hehe

SILICONEKID345HP

14,997 posts

230 months

Sunday 23rd April 2017
quotequote all
Mine sits at 135mm to the corner plate running 205 50 16.

Rear 150 mm with 235 45 17 .

It looks sexy with the stance but I think fronts need to be higher .
Bottom wishbones are nowhere near level .

SILICONEKID345HP

14,997 posts

230 months

Sunday 23rd April 2017
quotequote all
Mine sits at 135mm to the corner plate running 205 50 16.

Rear 150 mm with 235 45 17 .

It looks sexy with the stance but I think fronts need to be higher .
Bottom wishbones are nowhere near level .

ClassicChimaera

12,424 posts

148 months

Sunday 23rd April 2017
quotequote all
Set it higher and you might find your steering works better, centres better.

SILICONEKID345HP

14,997 posts

230 months

Sunday 23rd April 2017
quotequote all
Its not worth doing untill my new Nitron 400lb front springs turn up ..


ClassicChimaera

12,424 posts

148 months

Sunday 23rd April 2017
quotequote all
So this was all just so you could show off biggrin oh er missus, 400 nice.
What are you on at the moment ?

SILICONEKID345HP

14,997 posts

230 months

Monday 24th April 2017
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375 but they keep settling quickly so constantly having to adjust .

The rear springs still look like new .


phazed

21,844 posts

203 months

Monday 24th April 2017
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ClassicChimaera said:
Going by the corners of chassis I thought standard it's about 140-150 F to 150-160 R
But I could be wrong. thumbup
That's what mine is set to.