Adjusting ride height
Discussion
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).
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).
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.
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 said:
................the scenery is wonderful in Scotland but the roads are shyte
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 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.
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.
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.
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
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
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.
Sorry I was incorrect about the 20 mm,,, that's the fronts
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.
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