Mother Theresa

I was going to get some ASTs ...but.... someone accepted a very low offer I put in on some Ohlin 3-way adjustable coilovers so I now have them with various springs to go with them. The rears currently have 45Nmm springs on and I have the choice of 75, 60, or 45 for the fronts. They are not fitted yet so I have not had time to experiment but should it be OK if I have 45 front and rear? I know Powerstation go for 60/50 or 50/40 but would I notice much difference 45/45?

Thank-you in anticipation.

jupiter

For what car make ?.

For wrx my01 newage , smooth gravel setup with ohlins three way adjustable , springs are 50N/mm at front and 35N/mm at rear. Given this, i would recommend not to go harder than 60N/mm at front.

Everything depends also and on the setup of the dampers ( shim stacks, damping forces ). Are the dampers you have tarmac or gravel set up ?.

Since the setup is quite difficult to achieve without a starting point, i would say to contact a local Ohlins Dealer to get the initial recommended settings from Ohlins. I believe that there is a number stamp at the top hat of each strut ( something like SUR1B00).

Given this number a local Ohlins dealer or even Ohlins Sweden should be able to advice on type and recommended setup.

Good Luck.

silent running

If you don't mind the messing about, why not try them all yourself and see what you like? I did that on my old Clio getting the spring rates and lengths right, trying single rate, double springs etc. In the end I got there. Depends on how much time you've got on your hands though...

Mother Theresa

They say "rough tarmac" on the cannisters and will be going on my MY03 WRX wagon.

For my baby I have all time in the world - but wouldn't mind knowing where to start.

911

I think you need to try the springs you have.

On my AST 3 way (and my previous 1 way) I used on my Classic 50/40 and then 60/50.

These are on a hillclimb/road legal car, so sort of tarmac stage 'conditions'.

I would try them and see if the existing spec of internals can damp the springs, start at the soft end, ie 50/40.

I was always told (and it works) that the rear rates should be close to 80% of the front, so 50/40 is spot-on.

Good luck and take it easy to start with!

Graham.

Fuzz

I'd go with the 60's on the front.


Andy

911

I've gotton used to my 60/50 now

Prescott in 2 weeks Andy, see you there?

I've got all these hot-shots chasing me now you have fitted AST's to their cars....

Graham

Fuzz

Probably not.
The landrover has taken a bit of hit because of all the time I've spent on the race car, not had much enthusiasm for it of late.
Must get on with it now, which means free weekends are in short supply.
Half my interior is in now though, I might see you next season at Prescott.

Andy

Mother Theresa

Thanks for all the above, I have spoken to the company who set the suspension up in the 1st place and their recommendation is to "underspring and overdamp" rather than the other way round so I'll kick off with with the 45's front and rear.

And keep you informed, of course.

911

Yes please as I will be interested to see how you get on with 45/45 and over damped.
Graham

Fuzz

You may find the rear "kicks up" over crests as it's the same stiffness as the front and is no longer balanced (80% split)


Andy

911

Exactly.

ukbob

hi guys,what are 60nm and 50nm springs in old money(lbs)please.

Fuzz

1 newton = 0.2248089 pound-force
1 millimeter = 0.0393701 inch

0.2248089/0.0393701 = 5.710143

N/mm * 5.710143 = lb/in

60 * 5.7 = 342.6 lb/in
50 * 5.7 = 285.5 lb/in


Andy

Mother Theresa

The suspension goes on next week but we have found some 55Nmm springs (albeit gravel length) so will try these 1st as they get closest to Graham's 80% figure.

JIM THEO

As you can see the front to rear weight distribution is more or less 14/10 thus your spring rate should follow this rule (7-5, 6,5-4,5 etc).
IMHO of course but if you see almost all known coilover manufacturers offer such combinations for our cars (Ohlins, Bilstein, AST, Whiteline, KW etc).
Depends also from the type of shocks you have, roads where you drive your car (smooth or uneven tarmac) and much more and finally your personal taste!
JIM

Mother Theresa

This is a new-age wagon so I don't know if it bu&&ers up your equation and the roads are Northamptonshire's worst C & D roads

911

Don't see why it shouldn't be valid.
Graham

JIM THEO

The most accepted spring combination in coilovers for our cars is 5-4lb/in (280-225), if you drive on C-D roads you need more suspension travel and good quality shocks rather softer springs, the same with your case applies to all Greek roads where we also have the worst tarmac!
I have tried some coilovers on STI and WRX and Ohlins is if not the best at least one of the best coilovers for bad road surfaces, it keeps the factory suspension travel (if you lower the front less than 3cm and rear about 2.5cm you have a very good balance and noise rake which helps you on understeering situations) and have good spring rates for road use.
I don't know though if yours is R&T Ohlins kit, a friend's Ohlins DFV setup is also very good but on the harsh side with 7-5lb/in springs better for track use!

Mother Theresa

So you reckon more like 50/40 - there seems to be some form of error with the units for either you or us. Well the 45's, 55's and 70's are all free as they came with the kit, anything else I will have to buy so I hope the 55/45 combo is OK as they are just over £50 per spring. Ouch. They go on on Tuesday.

911

IMHO: Good starting point. You may well not need to look any further!
Graham

JIM THEO

I believe 55-45 is a very good setup not very hard, I just mention what rates use most coilovers manufacturers!

Mother Theresa

They're on, they look the dogs. They have been set up for smooth tarmac rally settings by the guys which clicks from soft is:

Front: 37H 10L 34 rebound
Rear: 34H 8L 34 rebound

1st impressions. Absolutely no difference around town except over speed bumps - which is a good thing. As the speeds came up to 60-70mph on the way in I was beginning to brace my back before known bumps which tells me they are a bit hard on the high speed setting. Cornering was fine but not pushed as I have a boot full of suspension parts which were starting to slide around. All the lift-off oversteer has gone though. I'll rag it properly when doing my visits this afternoon.

Mother Theresa

Update. Could not provoke any sort of slide on any corners on the twisty lanes, but speed limited as a) I don't drive like a moron anyway and b) I had a dodgy Chinese and the guts just won't take it today.

Try again tomorrow.

911

Pic with the Report for top marks please!

Mother Theresa

No pics yet, sorry. Guts sorted so really gave it some stick yesterday and it was unreally good. There is a vicious 90 left at the bottom of a hill with really poor asphalt repairs on it and I can always get the back to step out wet or dry. I went into it 10mph faster than I usually dare and then saw a car coming the other way so had to tighten the line more than was expected and there was not the suggestion of movement from either end. Magical grip. The only downside is I took the g/f out in it last night and she has refused to go out again until I loosen the ride a bit. Hmmm.

911

Excellent, 8/10: 10/10 when you post pics and the GF is happy again (who needs the grief?)
Graham

Mother Theresa

Here goes with first ever pictures uploaded...

Fronts:

Rears showing external reservoirs:

and a bit closer up:

and inside at the front: