Question for all those who have Rover engines and who also have Gerry's tubular wishbone front suspension.
What are your spring rates.
I have for years been happy with 250lbs rating but discovered recently that I had run out of suspension adjustment.
Since discovered that these were only 8" not 9" so that would equal approx 1" less adjustment.
Gerry apparently only stocks 325lbs springs for Rover engined FIA's which having just fitted these I find them too hard. Probably great for track work but not particularly compliant for our bumpy roads.
Comments please before I go purchase some new ones. 250 x 9" or 275 x 9" ??
Peter C
Rover engined front Spring rates
Re: Rover engined front Spring rates
I have made a discovery on the Hawk tubular wishbone design. With the help of Karl measuring his and comparing notes, it appears older wishbones are 20mm longer than the more recent fittings. My guess is that this co insides with the change from spline to pin drive and the increase in width of wheel from 6.5" to 7.5"
Most importantly is the radial location of the spring/damper mounting as this will affect the spring rating.
Taking Gerry's latest stock spring for Rover FIA at 325lbs and calculating the rate required for mounting 20mm further out it translates to approx 300lb. Now I know this is a little dangerous and that really one should investigate the whole geometry of the hub area but at least it gives a starting point to head for.
Having used 250lb springs for 15 years and been relatively happy I wasn't about to immediately jump to 300's
I also had this inkling that I my car started its life on 300's before downgrading to the 250's because it was too hard then.
I was advised to look closely at the old springs and noticed tell tale marks of bottoming out. Possibly due to them only being 8" not 9" but also that nagging doubt that perhaps the 250's we're being punished too hard. You don't need me to remind you of the state of the roads!
So a bit of a dilemma just go for 250 x 9" to avoid coil binding or play safe and go up a grade as well. So I have taken the plunge with 275lb x 9" and will let you know how they perform.
It would still be interesting to know what spring rate others use with older tubular wishbones and a Rover engine.
Peter C
Most importantly is the radial location of the spring/damper mounting as this will affect the spring rating.
Taking Gerry's latest stock spring for Rover FIA at 325lbs and calculating the rate required for mounting 20mm further out it translates to approx 300lb. Now I know this is a little dangerous and that really one should investigate the whole geometry of the hub area but at least it gives a starting point to head for.
Having used 250lb springs for 15 years and been relatively happy I wasn't about to immediately jump to 300's
I also had this inkling that I my car started its life on 300's before downgrading to the 250's because it was too hard then.
I was advised to look closely at the old springs and noticed tell tale marks of bottoming out. Possibly due to them only being 8" not 9" but also that nagging doubt that perhaps the 250's we're being punished too hard. You don't need me to remind you of the state of the roads!
So a bit of a dilemma just go for 250 x 9" to avoid coil binding or play safe and go up a grade as well. So I have taken the plunge with 275lb x 9" and will let you know how they perform.
It would still be interesting to know what spring rate others use with older tubular wishbones and a Rover engine.
Peter C
Re: Rover engined front Spring rates
For those interested - an update on Spring rates.
I purchased a pair of 275 lb x 9" springs from Faulkner Springs near Chichester. A warehouse in someone's back garden packed with springs. Apparently they supply the Subaru rally team amongst other top line competition teams. Springs are made to very high accuracy so they don't have to fiddle around to find a matched pair.
Very polite and helpful and also prepared to discuss my setup. They checked the old springs to discover they were well past their prime. Read knackered.
So with new springs fitted so far so good. Ride quality a little firmer but this would be due to the fact that the old 250lbs units had lost a fair bit of their rated value.
Ride height re set and camber corrected to 0.8 neg ( was 1.25 neg partially due to the sagging springs ). So now it's on going road testing and perhaps just need to adjust the shocks up one or two clicks.
Peter C
I purchased a pair of 275 lb x 9" springs from Faulkner Springs near Chichester. A warehouse in someone's back garden packed with springs. Apparently they supply the Subaru rally team amongst other top line competition teams. Springs are made to very high accuracy so they don't have to fiddle around to find a matched pair.
Very polite and helpful and also prepared to discuss my setup. They checked the old springs to discover they were well past their prime. Read knackered.
So with new springs fitted so far so good. Ride quality a little firmer but this would be due to the fact that the old 250lbs units had lost a fair bit of their rated value.
Ride height re set and camber corrected to 0.8 neg ( was 1.25 neg partially due to the sagging springs ). So now it's on going road testing and perhaps just need to adjust the shocks up one or two clicks.
Peter C
Re: Rover engined front Spring rates
Hi peter, how are you finding these springs now after a bit of use?
Nige
Nige
Re: Rover engined front Spring rates
Nige,
It appears pretty good so far. A little stiffer than the old knackered 250's obviously but certainly acceptable. I'm not inclined to bother to try any 250's yet.
Compared to the 8" units the longer 9" spring not only offers an extra 1" spring travel but there are also less coils due to the higher quality steel used. Should help with the pot holes.
Peter C
It appears pretty good so far. A little stiffer than the old knackered 250's obviously but certainly acceptable. I'm not inclined to bother to try any 250's yet.
Compared to the 8" units the longer 9" spring not only offers an extra 1" spring travel but there are also less coils due to the higher quality steel used. Should help with the pot holes.
Peter C