Ride height

[JP]

So, having measured my old non-adj bilsteins (with spacer for sidetrack) against the new Pro-tech shocks, the total opening length is the same.  I am starting to think that the original non-adj suspension could never have been right for a 14" wheel; car moving to 13"s...were the adj bilsteins for widetrack longer when fully open than the non adjust ?

[JP]

So, having done a bit of research, I'm now starting to reach different conclusions about the ride height issue.  I would be grateful for any comments (including to be told that I've got it all wrong)...

1. The key issue with the starting point for the front ride height is that the bottom wishbone should be horizontal when weighted and at rest.  If one seeks to raise the front to get 75mm under the sump with 185/60/13s , then the front wishbone will have to have a steep downward slope from the chassis to the wheel, which will upset the rest of the suspension / steering geometry and function.

2. If that is correct, I do not see that it is possible for a wet sumped K-series to have 75mm of ground clearance under the sump if it is on 185/60/13s, given how low the sump sits in the engine bay.

3. The Caterham / Bilstein shocks for the std fixed set up and the adjustable set up are the same core shock - the latter just has adjustable platforms added (ie the full open length is the same). 

If all that is right, I just need some stiffer and slightly longer springs as my front wishbones are ever so slightly angled upwards at the wheel.  If anyone is interested, the full open eye-to-eye length of my old std Bilsteins was 38cm/15".  My Pro-techs are the same.  The stroke of the Bilsteins is about 60mm.  The Protechs are 115mm. 

I guess, on a wet sump K-series, that if one is concerned about ground clearance, the best solution is to use 14" wheels for regular road use and reserve the 13"s for track days...

Grateful for any comments...

[JP]

I've now spoken with Protech and had my setup done by PT and everything feels much sharper.  Surprisingly, just by following the build manual the setup was pretty close.

And I've changed front springs.

On the point about mounting protechs upside down, I have been assured (for the second time now) that there is no issue.  I am told that the protechs are indeed a twin tube design, but also that they are internally sealed and so cavitation won't be an issue.  My reasoning for mounting upside down is simply to keep road crap away from the adjuster knobs.