[ChrisRobin]

Ok I might just be frustrated and thinking irrationally here: Is there a way to take for example a Boxxer spring, cutting it and based on the new length and originating spring rate, calculate the new spring rate? (or even a Marzocchi 888/380 spring)

I'm about 8 rides in on my Fox 38 and I think the air spring needs a rebuild or lubing. When I say 8 rides, they're not more than 1.5 to 2 hours long. I haven't fully taken it apart to see but that's what I'm suspecting. To thoroughly lube the new air spring, some 10mm shaft clamps (which I have, I think) are required and a bullet tool which I don't have. I'm already brainstorming on how to convert this thing to coil.

 

[Kanye West]

This sounds like some crackhead shit.

 

[tacubaya]

Get a Vorsprung Luftkappe or a Secus and forget the coil spring.

 

[Jm_]

Would the spring rate not change, only that you may not be able to compress it as far? Would the problem not be that if x spring worked for you with 8" of travel, if you chop off whatever % gives you 7" of travel, you now need a HIGHER spring rate, to avoid bottoming and using too much travel?

 

[Westy]

Would the spring rate not change, only that you may not be able to compress it as far?

Spring rate does change inversely to the length of free coils. A coil spring is effectively a torsion spring in a compact package.

A progressive coil spring works by reducing the free coil length as it compresses.

 

[Jm_]

Spring rate does change inversely to the length of free coils. A coil spring is effectively a torsion spring in a compact package.

A progressive coil spring works by reducing the free coil length as it compresses.

Smarter every day.

 

[xy9ine]

This sounds like some crackhead shit.

ah, memories of cutting coils on the civic as a kid. bouncing off the bump stops on blown shocks, getting stuck on speed bumps, etc...

 

[ChrisRobin]

I pulled apart the fork and was able to remove the air spring assembly out of the uppers. By moving the air spring rod by hand, I was able to feel the notchy-ness I was feeling when the fork was on the bike. But I can't take apart the air spring assembly without this stupid Fox 10mm bullet tool that's not available anywhere. Lol.

edit. I cant probably buy one of Vorpsrung's bullet tools. I'll call them tmo.

 

[FarkinRyan]

I pulled apart the fork and was able to remove the air spring assembly out of the uppers. By moving the air spring rod by hand, I was able to feel the notchy-ness I was feeling when the fork was on the bike. But I can't take apart the air spring assembly without this stupid Fox 10mm bullet tool that's not available anywhere. Lol.

edit. I cant probably buy one of Vorpsrung's bullet tools. I'll call them tmo.

If you already have the assembly out of the bike try greasing the exposed air shaft with some slickoleum and cycling it to see if that improves the notchiness. Take a look down into the air tube with a bright flashlight and see if there looks to be a decent amount of slickoleum in that chamber too both on top of the piston and a film on the inner walls of the tube, if there isn't you can very carefully add a little slickoleum as far down as you can with something non-scratch and again cycle the piston by hand to distribute it around. Not a perfect solution but will at least give you an idea whether lack of grease is the problem.

 

[englertracing]

This sounds like some crackhead shit.

Sorta

Get a Vorsprung Luftkappe or a Secus and forget the coil spring.

Maybe, I mean the 38 should work wellish with its twin toobz air spring.

Would the spring rate not change, only that you may not be able to compress it as far? Would the problem not be that if x spring worked for you with 8" of travel, if you chop off whatever % gives you 7" of travel, you now need a HIGHER spring rate, to avoid bottoming and using too much travel?

Putting two springs in parallel = twice as stiff
Stacking two springs in a series halves the rate

Cutting a spring always makes it stiffer roughly by the amount removed.

I pulled apart the fork and was able to remove the air spring assembly out of the uppers. By moving the air spring rod by hand, I was able to feel the notchy-ness I was feeling when the fork was on the bike. But I can't take apart the air spring assembly without this stupid Fox 10mm bullet tool that's not available anywhere. Lol.

edit. I cant probably buy one of Vorpsrung's bullet tools. I'll call them tmo.

There are tons of spring calculators online.
All you need is the od, wire diameter, and coil count.

I have a seal bullet...
Only takes 10 mins to make one on the lathe...

 

[HardtailHack]

What englertracing said.

I had my coil Totem and X-Fusion Vengeance at about 120mm travel after spring chops. I used a pencil type tip on my blowtorch, put a soaking wet rag in the spring a coil or so down then got two small sets of Vise grips to hold the coil compressed when I got it to cherry red.

I hit the bottom of the spring on the linisher(upside down belt sander), the spring rate probably changed for the worse at the end I heated but I never had an issue. The hardest part is lengthening whatever you have as a top out system and getting the neg spring rate right for your weight.

 

[ChrisRobin]

I was able to make a ghetto bullet tool and put the whole thing back together. I figured out that notchiness is the air piston moving the negative air spring equalization port. It's not as bad as before but it's there.

 

[englertracing]

Did you use slickoleum and a few drops of float fluid?

 

[ChrisRobin]

Yeah, I used a bunch of it (but too much that it accumulated too much under the piston) and used the 3cc of Fox 20w.

 

[marshalolson]

Cutting a spring always makes it stiffer roughly by the amount removed.

Just to reiterate, in case missed...
cutting a spring in length by about 10% make it about 10% stiffer as a result