Which BC's do you have?
The standard coilovers or the inverted monotubes (RM series).

_________________
Vice Chairman
1990 White UK Celica ST185 - Project DTM
1997 Cream BMW R1200C (as seen in James Bond "Tomorrow Never Dies")
2005 Jaguar X-type 3.0 Sovereign AWD Automatic
Blood Bikes - https://www.freewheelers.org.uk/

could they add more rebound on the first perchase of the units? i mean befor i brought some,could this be adjusted?

I got the normal ones. They don't offer different damping rates from new, but can or will do different springs.

I most likely will go to 5kg/mm on the rear next.

_________________
--

Darryl

are you happy with them in all though?

Are the BC's as short stroke as the D2's as this, IMHO, is their main failing on UK roads in that they blow through their travel on speed humps/potholes and give you a nasty bang?

Not great on Derbyshire B-roads!!

The rest of the time excellent.

John

Oh yes most definitely, would buy them again, if I was doing it again. As I said I'd have 5 kg / mm on the rear springs personally, would help the slightly understeer brought in by the soft rear end. You can cover it by upping the damping, but its too firm in my opinion when on approx 24 out of 32 which is needed to keep it neutral when using the standard supplied 4 kg / mm rear springs. I have a standard arb, so the usual whitened might not suffer this trait.

However the runs 60 / 40 front to rear weight, so that match of 8 front to 4 rear is poor imo.

_________________
--

Darryl

Do not up damping to make the car stiffer. Up the spring rate and match the damping otherwise you'll overwork the dampers and the damping will not be optimal for springs.

HTH

John

i said, as the rebound damping is so poor, you need to run more compression damping to counter it.

the spring rate is good enough, and if you were to up the spring rate, you'll only show the weak rebound range worse. its not raised bumps causing the trouble its the extension into pot-holes.

the cheaper (BC) dampers only have the compression adjustable. i generally like soft damping.... i'm not running them at the max, approx 3/4 of the adjusting range.

however its the poor match of compression to rebound, that does not suit b-class uk roads, which will be easily overcome, by using a suspension specialist to re-valve them at the time of a maintenance rebuild. all will be fine then.

_________________
--

Darryl

i have to say that the D2 set up i have on my car is great good on the road and just as good on track

_________________
BRD Page

http://www.brooks-brd.co.uk/

https://www.facebook.com/Brooks.Racing.Dev

Hmm I thought you meant up the damping to control understeer.

I also assumed they would have had reasonable spring rates to start with. My old D2's were 7/5 which seems a lot better than 8/4.....crazy!

Yep, you need a wave washer removing/replacing.

IMO you would be better off converting the struts to 40mm bilstein upon rebuild as you've got a good base to start with with the struts themselves. If you've got the wonga convert to remote reservoirs too with independent compresssion/rebound adjustment.

I've learnt a lot from my time with D2's, AGX conversions etc and know exactly what I'm doing next time. I ended up with 10.5" springs and 2" helpers on my old AGX's for a good b-road ride.

Personally I do think the RM GR (inverted gravel) series would be pretty good for the roads here if they've sorted the damping out. A chap has reviewed them on alltrac.net. For the money though I think I could do a lot better DIY.


John

Yes, custom building .... if you know what you want is the way to go. I needed to replace top mounts and the spring rate was a little to soft. Plus the springs had settled a bit too much on my stock CS suspension.
I knew the damping wasn't what I wanted, but the price for easy weekend swapover of parts ( my car is a high mileage daily driver ) and leaving me in a good place to adjust / tailor to my needs . Means I got them happy I am for the cost.

New rear springs are very cheap, rebuild ability means I can get the damping fixed, and I've been able to get more Castro and camper at the front end. It's a win win for me.

_________________
--

Darryl

I have tried a number of spring rates
and have settled on 8kg up front
but found 6kg at the rear too strong so have fitted 4kg.
6KG hardly moved, no compliance at all.
These are allied to 5kg tenders up front and 4kg tenders at the rear,
may go to 5kg tenders at the rear.

Coilovers are hard on suspension components
and I am fitting Polish Paul's front droplinks this week.

I am interested in what spring lengths and diameter are used by BC?

Suspension seems to be a dark art!
Tein have recently altered their spring rates, which are now the same as USA ones.

BC seem to have listened to UK feedback on rates?

Stephen

_________________
1993 Carlos Sainz 2939, Forged, Apexi RX6B turbo with external wastegate. MOTEC M4, AFPR and 800cc injects. 3" exhaust, +1mm valves.ST205 cams. Rays 8.5" x 17". 205 rear subframe. Bilstein coilovers. 205 brakes.TRD diff

Coilovers aren't hard on components, not any worse than any other suspension setup.

It's the choice of springs AND dampers ( well the damping level ) that can make it harsh.

Springs don't actually have any effect on the ride unless extremely soft or hard. (after all, the force of the bump, will still be passed to the car, weather you have a soft spring, or a rick hard spring )
A wide range of spring rates will work very well. People, spring rate determines suspension travel and the cars ride set into the dampers stroke. Damping controls the ride quality.


For a fairly normal weight st185 approx 7 or 8 kg/mm on the front will use 2 1/4 to just under 3 inch of damper stroke. Now as long as total damper travel is over 4 inches then you have a good starting spring rate.

The BC kit I have has a damper full stroke of just under 5 inches. ie. it settles just under half its stroke on the road. perfect.
that front spring I've got my measurements as 12.5 mm wire, 180 mm free length 5 coils. 62 mm internal diameter.

The rear coils are 200 mm free length 6 1/2 coils 10 mm wire . Damper I got 128 mm stroke. The rear spring is 4 kg/mm ..... (sorry I'm mixing units) but that weak a spring uses over 3 inch of the 5 inch travel. A fraction too much in my usage of my car.
As you rear load the car with the boot being used or carrying people. The 5 or if you carry lots of weight the 6 kg/mm spring would be a better match. once you have the car using approx half its damper stroke, you have a spring right for our UK roads, mixing bumps and pot holes.

its damping that makes it harsh or wallowly, not the spring rate.
of course you could say put a 30 kg/mm spring on the rear, and you will have so little movement going on, the damping wont matter one iota, which is true, but get it roughly right, and then its the dampers, not the springs controlling how you feel the ride.

_________________
--

Darryl

Hello Darryl

Thank you for sharing information.
My own setup is hybrid, loosely based on JIC
but using KYB AGX dampers.
The original dampers were very short and very shot.

I agree with using 8kg up front,
mine being 8" long allied to 2.5" 5kg tenders.

I had 6kg on the rear
and the ruddy things didn't move.
I have changed to D Faulkner 2.5" - 65mm diameter 4kg springs that are 8" long. Maybe I have a better spring than BC?
Getting more movement has caused the rear AGXs' to blow, but they were 3 years old!
When I change the rear AGXs' I may also change the rear tenders
currently 4kg x 2.5" long to 5kg x 2.75 - 3" long.

I may be able to supply tenders
using Eilbach which seem to be very good.

Stephen

_________________
1993 Carlos Sainz 2939, Forged, Apexi RX6B turbo with external wastegate. MOTEC M4, AFPR and 800cc injects. 3" exhaust, +1mm valves.ST205 cams. Rays 8.5" x 17". 205 rear subframe. Bilstein coilovers. 205 brakes.TRD diff

so taking your front end, how much travel before the 2.5 inch tenders go coil bound ? i guess they are on a 10mm wire ? and what 1.5 coils ?

_________________
--

Darryl