RSA suspension change?

[Chris71]

My car is still set up for track use on ultra-grippy slips. Even on hard road tyres it behaves admirably on a nice smooth race track, but on a B-road at any sort of speed you almost always have at least one wheel off the ground. I think even for a regular track day attendee this is a tiny bit extreme for what is also an occasional road car, so I'm planning to change them (and maybe keep hold of the originals for track work). Wondered if I could pose a few questions...

• What springs/dampers do you recommend for mixed road and track use? I've been very impressed with the ride on standard factory cars (a lot more compliant, but still reasonably well controlled...) I think this is probably the way forward, but I thought I'd ask.

• Will I have to change the anti-roll bars (I say that, I can't even remember off the top of my head if they're fitted at both ends currently...)

• What's involved in changing the springs and dampers over? Is it possible to specify fully built up spring/damper units and avoid messing around with spring compressors etc? Any consumables - bolts, bushes etc - I should renew at the same time?

• On a related note, I've been meaning to start rust proofing the back of the chassis - is there any advantage to doing this while the springs and dampers are off, or any other jobs I might want to think about piggy backing onto the procedure?

Oh, and slightly off topic, but while I'm on here, can someone recommend the best jacking and axle stand points?

[fergus]

Chris71 said:

ultra-grippy slips

They sound it!

[fergus]

Chris71 said:

* What springs/dampers do you recommend for mixed road and track use? I've been very impressed with the ride on standard factory cars (a lot more compliant, but still reasonably well controlled...) I think this is probably the way forward, but I thought I'd ask.

Depends how much you want to spend? Guy @ Nitron will custom build (i.e. custom valve) a set of 1/2/3 way dampers for you and suggest suitable spring rates for your application. Alterantively, you could go to Gary @ Freestyle for one of his Avo packages. Crucially, both these options allow you to alter the ride height, which also allows an easy way of changing springs over if you don't want to compress the springs. (Spring compressors are rarely needed, to the extent that some owners fit tender springs to keep their springs centralised on the spring perch when at full droop!)

Chris71 said:

* Will I have to change the anti-roll bars (I say that, I can't even remember off the top of my head if they're fitted at both ends currently...)

Possibly, depending upon the spring rates you choose and how you want the car to handle. This is not a prescriptive choice though. May be worth moving to an adjustable, blade type front ARB, as this allows an almost infinite range of adjustment (given the properties (torsion) of the bar itself).

Chris71 said:

* What's involved in changing the springs and dampers over? Is it possible to specify fully built up spring/damper units and avoid messing around with spring compressors etc? Any consumables - bolts, bushes etc - I should renew at the same time?

It's usually a single allen key/bolt mounting both top and bottom for both front and rear. All you need to do is jack the car up and undo them! You may want to check the condition of all the suspension bushes if you're considering changing the dampers. I've got a bag of damper bushes you can have if you stick with std dampers.

Chris71 said:

* On a related note, I've been meaning to start rust proofing the back of the chassis - is there any advantage to doing this while the springs and dampers are off, or any other jobs I might want to think about piggy backing onto the procedure?

Just have a good look under the back of the car, check the A-frame, all the diff mounts for signs of cracking, the damper mounts on the de dion tube, all the brake fittings and unions. Signs of any leaks from any where. A general look around all the brazed joints around the diff carrier.....

Chris71 said:

Oh, and slightly off topic, but while I'm on here, can someone recommend the best jacking and axle stand points?

I use the front towing eye for most jobs and depending upon what I'm doing at the rear, either the rear pickup for the A Frame (compresses suspension though), or the two corners of the rearmost horizontal chassis member.

Next!

[Chris71]

fergus said:

Depends how much you want to spend? Guy @ Nitron will custom build (i.e. custom valve) a set of 1/2/3 way dampers for you and suggest suitable spring rates for your application. Alterantively, you could go to Gary @ Freestyle for one of his Avo packages. Crucially, both these options allow you to alter the ride height, which also allows an easy way of changing springs over if you don't want to compress the springs. (Spring compressors are rarely needed, to the extent that some owners fit tender springs to keep their springs centralised on the spring perch when at full droop!)

I presume the normal procedure is two of these:
https://www.caterhamparts.co.uk/product_info.php?p...
...and two of these:
https://www.caterhamparts.co.uk/product_info.php?p...

Jesus! That's £828 (I presume the prices given are per unit, not a pair!)

The ride/handling compromise on the standard cars I've driven was very good though and speaking to people about this the consensus was that factory springs and dampers are more than up to the job on track. I swore by the adjustables on my TVR (£600's worth of Gaz Gold Pros), but that was a big heavy car (in comparison) with a lot less structural rigidity - the Seven should be able to run a much more track-orientated setup on the road without affecting the ride too much. I'm not looking for plus, just something that keeps all four wheels in contact most of the time!

eta: Just spoke to Nitron and the basic kit costs £1,144 once you've factored in VAT. I know they're excellent shocks, but that seems like quite a premium. The Avo kits from Freestyle, in contrast, are either £499 or £644 depending on the body material as far as I can tell from their website.

Edited by Chris71 on Tuesday 21st July 14:51

[fergus]

Chris71 said:

fergus said:

Depends how much you want to spend? Guy @ Nitron will custom build (i.e. custom valve) a set of 1/2/3 way dampers for you and suggest suitable spring rates for your application. Alterantively, you could go to Gary @ Freestyle for one of his Avo packages. Crucially, both these options allow you to alter the ride height, which also allows an easy way of changing springs over if you don't want to compress the springs. (Spring compressors are rarely needed, to the extent that some owners fit tender springs to keep their springs centralised on the spring perch when at full droop!)

I presume the normal procedure is two of these:
https://www.caterhamparts.co.uk/product_info.php?p...
...and two of these:
https://www.caterhamparts.co.uk/product_info.php?p...

Jesus! That's £828 (I presume the prices given are per unit, not a pair!)

The ride/handling compromise on the standard cars I've driven was very good though and speaking to people about this the consensus was that factory springs and dampers are more than up to the job on track. I swore by the adjustables on my TVR, but that was a big heavy car (in comparison) with a lot less structural rigidity - the Seven just needs something to keep the wheels in contact with the ground.

I find the ability to back off my damping in the wet useful, echoed by the easily adjustable front ARB. I still need to get under the car to mess around disconnecting the rear ARB though!

[Red Seven]

Why not put a "Wanted" on Blatchat for a set of standard springs and dampers?

If buying new parts you'd be better with:-
These on the front https://www.caterhamparts.co.uk/product_info.php?c...
and These on the back:-
https://www.caterhamparts.co.uk/product_info.php?c...

That is with 150lbs/in springs and M0 dampers on the front, and progressive rear springs and M0 dampers on the back.
Standard springs and dampers still work well on track. I'd sell the "Race" springs and dampers and buy a set of standard ones.

If buying aftermaket dampers, then you pay for quality. Standard Bilstein dampers are a very good damper.
Cheaper adjustables, whilst adjustable, may not give consistent results.
ie, if you had the facility to test the dampers on a dyno, you may well find that "three clicks" on one damper is not equal to "three clicks" on the one for the other side of the car.
If buying adjustables, don't buy cheaper than standard bilsteins.

[fergus]

or, for the fronts..... http://www.pistonheads.co.uk/sales/1053397.htm

[fergus]

Red Seven said:

Cheaper adjustables, whilst adjustable, may not give consistent results.
ie, if you had the facility to test the dampers on a dyno, you may well find that "three clicks" on one damper is not equal to "three clicks" on the one for the other side of the car.
If buying adjustables, don't buy cheaper than standard bilsteins.

Agreed. If you're spending any cash on dampers, ask to see the damper dyno plot to make sure they're a matched pair in terms of damping "curves"/plot.

[Chris71]

Red Seven said:

If buying new parts you'd be better with:-
These on the front https://www.caterhamparts.co.uk/product_info.php?c...
and These on the back:-
https://www.caterhamparts.co.uk/product_info.php?c...

That is with 150lbs/in springs and M0 dampers on the front, and progressive rear springs and M0 dampers on the back.
Standard springs and dampers still work well on track. I'd sell the "Race" springs and dampers and buy a set of standard ones.

How does that differ to the standard setup?

Also, what's the risk level buying a set secondhand? The answer I suppose is 'it varies' but is there a rough guideline with regards mileage or anything?

ETA: What's the difference with the wide track springs and dampers? Is it just that the outboard mounting points are a further out so they're longer stroke?

Edited by Chris71 on Tuesday 21st July 15:53

[fergus]

Chris71 said:

Also, what's the risk level buying a set secondhand? The answer I suppose is 'it varies' but is there a rough guideline with regards mileage or anything?

Difficult to tell. As long as they're not leaking and are not physically damaged, you should be OK.

[Sam_68]

Fergus' original answer was pretty comprehensive and on-the-money. The only observations I'd add are:

• The price of decent adjustable dampers like Nitrons may seem expensive, but if you're serious about tuning your cars handling, there's no alternative. As Fergus said, the ability to play around with ride heights (and conveniently set corner weights) is worth it alone.
• Damping on very light cars like the Caterham is absolutely critical, unless you're running rock-solid sping rates for track use. It's worth paying for the very best. At the moment, there would only be two names in the running for me: Nitron or Penske. And if you're serious, you need at least two-way adjustment (which allows different bump and rebound settings). Three-way adjustment (which adds the capability to vary high speed (road imperfections) and low speed (roll, dive and squat forces) damping) is nice, but can just increase the scope for getting it wrong, unless you really know what you're trying to achieve.
• Given the fact that most cheap kit cars of the sort that many Caterham owners look down their noses at have (admittedly often fairly cheap and nasty) adjustable dampers, with adjustable spring seats, it tells you something about Caterhams opinion of its own customers that they don't offer them as standard...
• The downside of adjustability is that it gives you an almost infinite range of options to fk your car's handling up, though (and obviously Caterham doesn't trust its customers enough to fit adjustables as standard for this very reason). If you don't know what you're doing, get the car set-up by someone who does.

[fergus]

Sam - nice Sprint in your profile pic! My Dad has a very heavily modded (a la Tony Thompson 26R) S3.

[Sam_68]

Thanks - it is when it works!

I currently have the (bent) exhaust valve from number 4 cylinder on my office desk in front of me, to remind me to order a replacement!

[BertBert]

I am not sure I agree entirely with where Sam is going. I think if you want to tune your car for a specific track purpose (winning in racing for example), then maybe you'd be going for top spec dampers assuming the regs allow.

In my experience though, Caterham have done a very good job over the years in producing a standard setup that works very well. The concept that Caterham don't trust owners to get it right is just a bit silly.

I moved from standard caterham bilsteins to Avos from freestyle with the "secret" rated fast road/track springs. My motivation was to get adjustable platforms and uprated dampers. Not a great move though. Got the height adjustment, never got the handling back (even with Gary setting it up). Adjustment was pretty poor and one damper failed after a few k miles.

I think your starting point has to be to find out what you have got in terms of springs, dampers and anti-roll bar settings before just shelling out a chunk of cash on a new setup. You have to know the starting point.

Springs are easy and relatively cheap to change to see the effect. If it turns out that you have dampers which are too firm, then I wouldn't rule out the idea of buying used.

Bert

[sfaulds]

Unlike most other kit manufacturers, Caterham have dampers made to their specification and do some testing with them, hence they work pretty well out the box and aren't adjustable. If you were happy with the standard setup on other cars, then get that and use it on the road. Keep your existing dampers and stick them back on for trackwork.

Or buy something adjustable, stick some random springs on it and convince yourself it's better because it cost lots of money and looks good

[Sam_68]

I can see where you're coming from Bert (and sfaulds); yes, Caterham have developed a reasonable combination of springs and dampers that offer a good 'average' setting for an 'average' driver. If you want to be safe and, erm, average, that's fine and dandy!

Far from it being more important for track use, I'd argue that with a very light car like the Caterham, springs and (particularly) damping are actually more critical on the road, where you are typically running a more compliant set-up.

I'm afraid I can find no other good reason for Caterham not offering adjustable dampers and spring platforms apart from that they don't trust their owners to get it right.

Even if Caterham have found the optimum 'average' setting, there are a number of very obvious reasons that anyone competent would want the ability to fine-tune them:

• Personal preferences on ride and handling compromise
• Ease of corner weighting and accurate setting of ride heights (bearing in mind that the Caterham spaceframe isn't the most geometrically and structurally consistent device in the world).
• Different tyre characteristics
• Different mixes of road and track use/conditions.
• Even the very best dampers and springs have some range of consistency. I'm willing to bet that Caterham don't match their springs and dyno-match their dampers before selling them. A really good set of dampers (like Penske) will give you that opportunity.
• You're suggesting changing the springs without touching the dampers? That in itself is guaranteed to cause a mismatch, if you don't have adjustable dampers, because the dmapers need to be valved and adjusted to suit the spring rates.

To anyone remotely interested in handling (and surely that's most Caterham owners?) having non-adjustable dampers is a bit like having an automatic gearbox. Maybe it does change gear at pretty much the optimum point, 90% of the time, but the mere fact that you have very little ability to control it would be enough to rule it out for anyone who considers themselves an expert driver.

Even relatively quick-and-dirty, coarse adjustments can be useful; as Fergus suggests, even the ability to soften off the rear for wet roads or stiffen things up a bit for the occaisonal track day can be handy, and ultimately leads to a better understanding of your car and its handling.

...oh, and Avo's are nothing special, by the way. I'd rate them alongside Spax and Protech as one of the 'budget' adjustable dampers, so you really can't expect too much from them.

edited for grammar so crap I could spot it even when drunk

Edited by Sam_68 on Tuesday 21st July 23:58

[Chris71]

BertBert said:

In my experience though, Caterham have done a very good job over the years in producing a standard setup that works very well.

That's the thing - the standard Caterham really stood out to me as a great blend of body control and suppleness. I drove quite a few different examples and was continually impressed with the level of composure they maintained on typically bumpy B-roads.

I do understand Sam's comment about tuning the suspension to your requirements, but I honestly didn't find anything wrong with the factory setup to start with - I'm sure I'd be able to fractionally improve things with some adjustment, but it looks like you rapidly get into diminishing returns... fine if you're chasing the last hundredth against the clock, but a lot more money.

It is a good point about finding out what's on there. A friend who knows his Caterham's and has raced them in the past reckoned it was unusually stiff even for a track car.

[Sam_68]

Chris71 said:

...I honestly didn't find anything wrong with the factory setup to start with

Then sfauld's advice is good; if you're happy with the factory set-up, then no reason not to stick with it.

Caterham's basic set-ups are, undeniably, pretty well developed, so unless you have a definite idea of where you want to go, the maxim of 'if it ain't broke, don't fix it' probably holds true.

Leave the subtle stuff until there's something wrong enough with the standard set-up that you know you want to change it?

[BertBert]

Sam_68 said:

Im afraid I can find no other good reason for Caterham not offering adjustable dampers and spring platforms apart from that they don't trust their owners to get it right.

Even if Caterham have found the optimum 'average' setting, there are a number of very obvious reasons that anyone competent would want the ability to fine-tune them:

* Personal preferences on ride and handling compromise
* Ease of corner weighting and accurate setting of ride heights (bearing in mind that the Caterham spaceframe isn't the most geometrically and structurally consistent device in the world).
* Different tyre characteristics
* Different mixes of road and track use/conditions.
* Even the very best dampers and springs have some range of consistency. I'm willing to bet that Caterham don't match their springs and dyno-match their dampers before selling them. A really good set of dampers (like Penske) will give you that opportunity.
* You're suggesting changing the springs without touching the dampers? That in itself is guaranteed to cause a mismatch, if you don't have adjustable dampers, because the dmapers need to be valved and adjusted to suit the spring rates.

To anyone remotely interested in handling (and surely that's most Caterham owners?) having non-adjustable dampers is a bit like having an automatic gearbox. Maybe it does change gear at pretty much the optimum point, 90% of the time, but the mere fact that you have very little ability to control it would be enough to rule it out for anyone who considers themselves an expert driver.

When Sam said this, he was on drugs Most caterham owners do have adjustable platforms. Hpwever, he is talking of a level of sophistication that belongs in competition for the last hundreths of a second, not on the road, it's fruitless. I know of noone who even seeks to go here for road driving. Match springs and dampers before selling? Sam is dreaming. If you know anything about suspension like you may do, you will know that you can easily change springs and not dampers. There is no such thing as a magic matched spring and damper combination. Auto gearbox, what twaddle.

Sam_68 said:

Then sfauld's advice is good; if you're happy with the factory set-up, then no reason not to stick with it.

Caterham's basic set-ups are, undeniably, pretty well developed, so unless you have a definite idea of where you want to go, the maxim of 'if it ain't broke, don't fix it' probably holds true.

Leave the subtle stuff until there's something wrong enough with the standard set-up that you know you want to change it?

Sam arrives back on earth.

Bert

Edited by BertBert on Wednesday 22 July 00:15

[BertBert]

And to Chris, as an RSA car, it's only likely to have been fiddled with in the context of what's allowed in the regs.

My bet is that you have caterham race bilsteins and rather stiff springs. Sam will disagree, but I suspect that going for softer srpings might work, or you may need to go for standard caterahm bilsteins and softer springs.

Bert