Bilstein coilover insert lengths

[wicked 103 3 Cars]

 

I have set of Bilstein coilovers, forest/gravel spec that I converted from 70mm PTS springs to 2.25" springs with camber plates for my gti (road/occasional track). 

The coilovers came with some 10.5"-ish springs and I mounted 8" springs with 3" helpers to reduce ride height. I have mounted them and I am not really pleased with the ride height.  At the lowest setting they are just not as low as the previous KW coilovers.

Actually I would like to go to 7" springs, but think the inserts are way to long for that. I need to jack the car also much higher in order to get the wheels from the ground. With 7" springs, I also fear that the springs will come loose if I jack the car, which is an MOT fail here. 

 

Are tarmac spec Bilstein inserts shorter? I also read on here that fixed platform Bilsteins have the same length insert, which puzzles my a bit. I have a set of fixed platform Bilsteins (40mm rally kit?) that are much shorter and need to jack the car less high to clear the wheels from the ground.

 

Can anyone some light on this? Are there Bilstein inserts with different lengths available or is there a way to get them deeper in the bodies?

Would it hurt the inserts if I run them continuously compressed with 7" springs? I'm tempted to remove them again and use the shorter KW's again. 

 

I think my current inserts are the PTS 7234, but not sure.

 
 

 

 

Edited June 2, 2021 by wicked

[Thijs_Rallye 86 4 Cars]

I wouldn't be surprised if the gravel spec inserts have a longer overall travel then a tarmac spec tbh. If I were in your shoes and you have the insert part numbers I'd contact Bilstein directly.

The fixed platform Bilsteins (assuming you mean the 205 cup spec) are equivalent to the B6 in regards of length.

[wicked 103 3 Cars]

These seem much longer than fixed platform (both challenge and B6)

 

Number on the insert: 4711XDE 7880M2; looks indeed forest spec on Kamracing:

 

2 x Bilstein Tarmac Insert - F4-XDE-7880-M3  

2 x Bilstein Forrest Insert - F4-XDE-7880-M2  

 

Question remains if the 7880-M3 is much shorter? 

Think there is more knowledge here about 205 stuff than a the local Bilstein reseller....

Edited June 2, 2021 by wicked

[petert 550]

Pull the Bilsteins apart, unpick the platform mount and TIG it back on further down.

[wicked 103 3 Cars]

I think it cannot go lower? It is already at the bottom of the tube? (If I understand correctly what you try to do?)

[petert 550]

I’ve got the guards off, so easy to take pics and measurements tomorrow.

 

The picture you posted isn't loading.

Edited June 2, 2021 by petert

[petert 550]

Sorry, no progress today. Other life stuff got in the way. Hopefully pics tomorrow.

[wicked 103 3 Cars]

No problem, car won't move due to engine work and other priorities.

So no hurry... 

[petert 550]

In the pics, you can see my spring base adjusting sleeve is sitting on the anti-roll bar mount. I don't use a front bar, so I could grind those off and bring the sleeve down a bit further. My overall combined spring assembly height is 250mm, unloaded. The main spring is 150mm, unloaded. It's a bit hard to measure the overall length of the strut without a complete disassemble.

[wicked 103 3 Cars]

Thanks for the pics!

 

My bilsteins have a 1 piece body:

 

This was still with the 70mm springs. 

They don't have a seperate adjustment sleeve, so you trick won't work with my coilovers.  And I like to keep the ARB (road car). 

Dropping the spring seat down, would give the same effect as fitting 7" springs iso the current 8" springs (with 3"  helpers). That would still make that the springs come loose when the car is jacked. 

 

 

Meanwhile I've found this info on the forum:

Quote

Had a bit of a play with the 2 sets last night and they're actually fairly different!

 

The 300/120 set are short inserts, overall length of about 510mm if that makes sense, and have 8" springs.

 

The newer (to me) 250/180 set being 580mm, running 10" springs.

The forest inserts are indeed longer than the tarmac ones. 

 

So probably I need to bite the bullet and order tarmac inserts (and maybe have them revalved to forest spec) and order 7" springs. 

If I would order 7" springs with 4" helper springs, I fear the dampers will bottom out because of their longer length or need to remove the bumps stops... 

 

 

 

 

[wicked 103 3 Cars]

I also found this one for a forest insert:

 

So it has about 7" - bumpstop length of travel.

Probably not much room left to run 3" lower than intended. 

 

[welshpug 1,622]

I think you'll struggle to get silly ride heights with rally dampers, they are intended to still have some wheel travel and road clearance.

[wicked 103 3 Cars]

I'm not trying to get it very low. With the 8" I tried to get a drop op 40-50mm, same as what I had with the weitecs, but at the lowest setting they sit higher than the weitecs. 

 

When I bought them, I did know they were longer than tarmacs, otherwise I wouldn't have bought them likely. Did buy them because of the lower damping rate for the road. 

[wicked 103 3 Cars]

Topic kick...

 

I was bit bored on Boxing day, so I pulled the Bilstein box from the shelf and continued where I was left off...

I disassembled the forest coilovers from my Gti as well.

Meanwhile I have multi bodies and inserts to mix and match.  But I still struggle with the lengths of the inserts:

 

 

From top to bottom:

- B6 insert

- F4-XDE-7880-M2  250/120 (forest)

- F4-XDE-7880-M3  300/200 (tarmac)

 

It turns out that the forest inserts (M2) are also shorter inserts, like the tarmac inserts! (Both from Kamracing)

So swapping to tarmac inserts does not help.

 

In the end I would like to end op with 2 sets, both with ~50m drop from standard ride height. I have springs (matching with inserts) to get there, but I'll be almost riding on the bump stops.

 

Q1: How bad would it be if I shorten the bump stops? 

Q2: Are there even shorter Bilstein inserts available for track purpose? I cannot imagine that I'm the first to run into this problem? 

 

 

Edited December 27, 2023 by wicked

[petert 550]

Mine are easily +50mm lower than standard. I think it also depends a lot on how well you engineer the top mounts. The only way you'll know for sure, is to put it all together without springs and do some measuring by using a jack.

[wicked 103 3 Cars]

The top mounts are indeed a significant factor and think I already found a cm in moving rings, but the long top spindles kind of scare me to get to close to the bonnet. 

Atm I have compbrake top mounts and think I'll order some bakerbm topmounts; from pictures it looks like that the bearing is sitting slightly higher (=car lower) compared to the comp brake ones.  And the bakerbm's have caster (=bonus) and move the top spindle to a place were the can stick out higher than at the original mounting point. 

With that I likely can stick with the 8" springs and chop a 1/3 of the bump stops  and do a test fit without springs. 

 

 

Edited December 27, 2023 by wicked

[wicked 103 3 Cars]

I ordered BakerBm top mounts (did need an extra set anyway), but they don't differ much in effective height compared to the compbrake ones. 

Instead of the 8" springs I'll use 7" springs to reduce the amount of travel a bit and the need to put the rings at the lowest possible position. 

Edited January 23 by wicked