Large Diameter Rear Springs

[Chris J]

I'm just wondering if there would be a demand for large diameter springs for coilover struts?

My struts have 2.5" diameter springs, but I'm looking into the supply of springs similar to the ones on the new GAZ struts and the manufacture of some spring seats to fit. This may be a job too far, as I've got enough jobs to do (and fund!) on the car right now.

2.5" spring make perfect sense for choice, but they don't look right?

[strat6v]

Cheap to change though when you are playing around with spring rates. Best to experiment with the 2.25's, find what suits you then have some bigger coils made. There are some big differences in spring rates on various cars.

[SUSIT]

I'm just wondering if there would be a demand for large diameter springs for coilover struts?

My struts have 2.5" diameter springs, but I'm looking into the supply of springs similar to the ones on the new GAZ struts and the manufacture of some spring seats to fit. This may be a job too far, as I've got enough jobs to do (and fund!) on the car right now.

2.5" spring make perfect sense for choice, but they don't look right?

easy to get springs made to any diameter, and my understanding of spring is that you need less coils for larger diameter springs so bigger gaps between coils and less likely to go coil bound. but as a nurse not an engineer i may be wrong.
cheque in post chris

[Chris J]

I've maybe had a bit of a breakthrough with this after some info from Mark Cowling.

Alloy billet coilover spring seats are available off the shelf, and I've already borrowed some new ones. They're for Escort coilover Mk2 struts using exactly the same Bilstein inserts as my Beta case struts. The springs are a similar diameter to standard Escort Mk2 fronts, but not quite a large in diameter as the Beta fit GAZ or Leda before that.

'Haven't got the moment of truth yet, because I forgot to rattle gun the top nut of one strut to try it. (they're built up with small diameter springs at the moment)

[rutthenut]

Gerry Porkridge has provided large diameter springs, and alloy seats, for the rear struts. No idea if still available, or at what price, but I've had a few different sets of springs in this diameter for my car.

Agree with earlier comment that you may want to mess around with 'standard' size springs to decide on your preferred rate, then maybe switch to large diameter springs for appearance' sake.

Also correct that less coils are needed - think of the uncoiled spring as a long torsion bar. It's that length (and bar thickness) that determines the rate. When wound at a larger diameter, there are less coils. Other approach to avoid possible coil-bound problems on small-diameter springs is to use a thicker piece of wire to start with, so resulting in a shorter length of metal and less coils.

[Chris J]

Large diameter springs in all rates and threaded billet alloy seats are available off the shelf to fit my struts, so there's no problem.

I had a word with David Ainsworth regarding the springs and seats on the GAZ units he supplies, but the diameter of strut body (and thread) is larger than that of my Bilstein cases.

[strat6v]

Maybe you could use the small threaded spring seat under the bigger one, after boring out the bigger one that is?

What OD springs are you looking at Chris?

[Chris J]

What OD springs are you looking at Chris?

They're 133mm O/D. (The GAZ ones are 145mm O/D)

The alloy threaded spring seats for the 133 O/D springs will fit my struts.

[strat6v]

I would prefer larger diameter myself. Have to check i have clearance with the splash panels though.

[Chris J]

I'll try and take a photo when I get chance.

If I can get this to work, I'll have a pair of new (unbounced) 300lb 2.25" I/D 12" free length springs for sale, coated gloss black. Some new anodised sleeve type spring seats, and some top 2.25" spring seats too.