sonic fork springs

[Mal S7]

My new fork springs arrived today from the States.



I am replacing my trusty progressives that I have had forever. I've always thought they were pretty good but lately I'm looking for an improved ride. Despite backing off the pre-load so its now 'old-buick', the front end is harsh at highway speeds on the patchy roads round here. The jarring is tiresome on a long trip. I think its the compression damping as they work pretty good at soaking bumps at slower speeds.

I chose Sonic springs after reading a post by Blitz and his success with fitting gold valve emulators using these springs. viewtopic.php?f=1&t=2598 I want to fit the gold valves, but will just fit the springs for now and see what difference they make.



That's the progressive spring on the left.

The Sonic springs have a spec of 0.65kg/mm. With my daughter's help I tested them on the bathroom scales, yep, about 65kg to compress 100mm. They are a straight rate, so no progressive increase in the rate. I pulled out my old springs and also tested these on the scales. To my surprise I got exactly the same result hmmmm of course that's not a complete test, as I don't know what the progressives do after that first 100mm, it was all I could do to compress them that much. Still, it makes me wonder if the difference will be that noticeable.

I've left the oil untouched (7.5wt) just checked and adjusted the level, cut spacers to 60mm length which gives 15mm preload and a laden sag of ... 60mm. A bit more than I had before. It's a rainy weekend but I hope to test it out next week on the run to the Alpine Rally.

[Major Softie]

What you are trying to fix doesn't sound like springs will help, but good luck.

[dwerbil]

I put in Progressive springs on my /7 about 6 years ago on the medium setting. The front suspension still seem to perform fine for me. But it's all relative to me....I just don't know what to compare them to. The ride seems fine? I guess that's what's important.

[Mal S7]

What you are trying to fix doesn't sound like springs will help, but good luck.

Yes, I agree MS. Not expecting the springs to solve the problem. Went for a test ride and they havent. I plan to fit gold valves; Racetech are adamant they wont work with progressive springs, thats why i got the Sonics. The ride was no different on the bumpy highway. Feels less mushy though (thats as quantitative as i can be) and I did find an improvement at 60 -90km/hr on the corrugated dirt road. Going to try as light a fork oil as I can get now. I expect that to improve the ride at expense of wallow.

[Major Softie]

Going to try as light a fork oil as I can get now. I expect that to improve the ride at expense of wallow.

Most likely, but if your compliance to small bumps is from some other problem, then you might get wallow, and still NOT get improved compliance over small bumps.

Have you checked fork alignment and stiction? That can compromise the performance of an otherwise properly setup fork, especially in the circumstances of which you speak.

[Mal S7]

Have you checked fork alignment and stiction? That can compromise the performance of an otherwise properly setup fork, especially in the circumstances of which you speak.

All rebuilt and checked and tested on tour, no problem with alignment or stiction but I need to try really light oil to rule it out. I figure if its still harsh then gold-valves wont fix it either. I can live with an old boat for the sake of sneaking up on this. Change of oil is cheap and easy, the valves cost a couple hundred and by some accounts, lots of friggin' around to get right.