BBR Spring / Koni Damper Setup - Ride Height & Sag (Formerly Koni Dampers on the NC - Ride Height Adjustable? Thread)

Having recently fitted my recently acquired BBR Koni suspension setup (second hand, roughly 2k miles on it, PRHT variant and sat well on the previous owner’s car), The rear is sitting far to low - before and after measurements here:

Old measurements (std sport tech, Level ground, half tank of fuel):
Right Front: 365
Left Front: 365
Right Rear: 365
Left Rear: 355

New measurements (BBR kit, level ground, half tank of fuel, handbrake off)
Right Front: 335 (-30)
Left Front: 335 (-30)
Right Rear: 310 (-50)
Left Rear: 315 (-45)

Speaking to BBR, they said that the spring perch height is adjustable, making me breath a sigh of relief. However looking further into it, a lot of the Koni sport yellow dampers do appear to be height adjustable (including the NA and NB variants…) however looking at mine, it looks suspiciously as though the spring seats are welded on, thus not adjustable…!

So the question is - do any of you have these damper on your NC, and if so are they or are they not height adjustable?!

Cheers!

For reference, pics of the dampers below:


Close up of spring seat as fitted:

NA/NB Konis were height adjustable. Maybe BBR were thinking of these.

What process did you go through to tighten the rear bolts? Is it possible you had extra weight on the rear( bushes twisted in opposite direction)

@saz9961 That’s what I’m thinking… hope not as I need to find 20mm from somewhere!!

@mk375 I tightened the bolts with he car on its wheels - the only potential issue could be that although it was on its wheels, the wheels were on ramps where as the front was on the ground, so on a slope. Wouldn’t have thought that would cost me 20mm though?

I understand why you needed to raise the rear on ramps but it may indeed be the cause of the problem. You could try putting the car on jack stands and jacking the rear hubs individually until you get the 350 mm then loosen and retorque the bolts

An option I considered to raise the rear was to cut a spacer out of a sheet of hard alloy to fit between the shock ‘top hat’ and the chassis. You could get another 10mm that way.
Or you could get spacers between the spring and shock, that would increase preload on the spring causing it to sag less under its own weight.

I rejected both options because I was not convinced I would get enough height.

I also looked for longer springs (Auto Doc has many makes and options, but it is hard to compare spring rates and so on without a lot of Internet searching), but ultimately just imagined me throwing good money after bad.

Long story short, for me, the best option was to cut my losses, sell mine on eBay and buy a new set of adjustable ones. Decision boiled down to MeisterR vs TEIN Flex Z. Similar price, TEIN also has a £300 option to control damper settings via a control box in the cabin which would be excellent. But MeisterR was the proven option (also much prettier), and I have no regrets buying them.

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@McTrucky I’m very reluctant to put more money into this option other than the geo - It’s going to BBR on Tuesday for that and I’ve asked them to see what they can do to address the ride height at the same time (that’s where the conversation re adjustable perches came from).

@mk375 I’ve tried re-setting the bushes this morning using many differing techniques and measurements but to no avail. Really hope BBR can do something with it otherwise I wont be keeping them on which will be really disappointing!

Is yours a mk3 or a later update? Assuming everything else is the same between your car and the previous car the BBR gear was fitted to you would think the only variable would be torsional strength in the bushes once the bolts are tightened. Is it possible that your bushes are twisted or torn and offering no addition to the suspension effective spring rate

Yep, came off a club member’s mk 3.5 (and was fitted to it by BBR), gone onto a mk3.5. He’s sent me the pictures of his car on these struts and it looked spot on so I can only assume its something amiss on my car.

Like I say, it still needs geo-ing and i’m sure the rear wheels have too much camber on but I wouldn’t expect that to be costing me that much in ride height.

Hmmm, so the car is back from BBR, I’ve not measured the heights yet but they look a little better post geo But still not right.

However, BBR are saying that the reason the rear is lower than the front is that the springs have sagged. This seems pretty poor given I was told (and I’ve no reason to doubt) that they had only done a little over 2k miles. BBRs view is that if they have done that amount of hard driving, or if the car has been sat for a long time, that would cause the sag… not sure I’m buying that one.

Anyone have any views on this?

I presume they are H&R springs? If so, sag is unlikely. If they are no name no brand £25 options, then maybe… but Koni I thought would have H&R.

To establish if it is rubbish springs, I guess you could measure full extension (jack up the car to the point where the wheel leaves the ground) compared to ride height. Then ask others for comparisons.

What doesn’t make sense is the car they came off being fine, and yours not… Spacers?

They are, apparently, BBR’s own springs - from their site “ specially-developed progressive wound BBR lowering springs. ”

I have been looking into spacers but I’m yet to find any suitable for the nc unfortunately.

If they have sagged, even if they have been driven hard etc, sagging after 2k miles to me seems very poor!

Will measure the ride height post geo tomorrow morning and update.

Heavy wheels don’t help.

The original SAZ9961, as brought in 2000.

Previous owner had fitted heavy 17s, PI springs on stock shocks. Nominally, these springs were supposed to be a 35mm drop. As measured, they were a 55mm drop,

Post Geo Ride Height update:

Front Left: 337 (+2 from install, -28 from stock)
Front Right: 337 (+2 from install, -28 from stock)
Rear Left: 325 (+10 from install, -35 from stock
Rear Right: 315 (+5 from install, -45 from stock)

I’m happy with how it drives but I would like it level, so I think its time to investigate spacers or shims

You will probably have a difficult job guessing what size spacers to fit if on the springs themselves as you can’t assume a certain thickness spacer will lift a corner by that same amount. Even with spacers fitted the spring rate on sagged springs may be different across the axle. Think you may be better off with new springs

Should have just stuck to the original plan and saved longer for Meisters…

Those heights are without a driver, right?

Yes, no driver but this time it had a full tank of fuel.

Just to add to the fun… The car came back from geo at BBR with the steering off centre- its right hand down just enough to be annoying. I’d send it back but they are now on shutdown for two weeks.

This is going well!! Starting to wonder if I should have just left the bloody thing alone!

Updated the thread title to make it more relevant!

I think when it goes back to BBR for them to do the steering properly (still a bit irritated about that, expected better from them!) I’m going to get them to put som fresh rear springs on as well, so long as they are sure that it’s would sort the issue.

Fingers crossed…!