help w/ rear suspension tuning...

[keen]

 I have a 2001 Disco monkey I just built up. I am running a 5" Marzocchi Z1 (heavy springs) up front. I have a Stratos Helix Pro for the rear. I ran it w/ the 500# progressive spring, 200 psi air, 6mm spring pre-load- way to soft for me (200#). I figured I'd call Stratos for some tuning info/ spring recomendations... well after getting of the phone w/ the saleswoman I felt like ditching the Stratos. She punched #'s (my weight, suspension travel etc.) and based on a formula came up w/ the 500# prog.- ok that's too soft- after the calculations were read- no more technical expertise. I asked to speak w/ a tech. and was told straight up they don't have time to talk w/ everyone that calls or they wouldn't make any money. Ok I spent $400 on shock and can't even get a spring recomendation. I am thinking of going up one step to a 600# prog. spring but ride XC so maybe a 550 linear??? someone point me in the right direction or i'll go broke trying different springs. Thanx

[Matno]

Yeah, I haven't been very impressed with their spring recommendations. I guess it's kind of hard to really know what spring weight is best for the huge variety of different bikes they make springs for. On the other hand, even the people on this forum will give you widely varying reports of what spring they like best. I'm only 140, and I didn't like my 500# spring, although it wasn't unbearable. A linear 400# spring was a slight improvement, but I'm still planning to get another Stratos progressive, maybe in a 350# weight. On the other hand, guys here ride everything from a 300# spring for a 163# rider to a 700# spring for a 210# rider (that was Stratos' recommendation and he was looking for a lighter spring, although it sounded to me like it was set up well for XC riding). Personally, I think most shock companies' recommendations are too heavy. Advise here has been to say you weigh 50# less than you do when getting a Risse shock valved. Maybe the same advice holds true for Stratos springs.

A couple of other points: First, what bike did you ride before the Disco Monkey? If this is your first full suspension bike, that would make a huge difference.

Second, how long have you been riding the Disco and what kind of trails are you riding? (i.e. where you live would be helpful). XC is a pretty broad category. Some people's "XC" is totally flat, my idea of XC includes rough technical rock gardens and the occasional 2-4 foot drop. You might find that you like it if you give it a chance. Ideally, (in my opinion) you want a shock that is as soft as possible without bottoming out too much. It should be set up so that it just barely bottoms out on the biggest drops you take.

Third, don't get a progressive spring unless you want to sacrifice small bump smoothness. I did, and it helped me to get full stroke travel, but didn't make the initial stroke travel any smoother. Stratos claims that their progressive springs generally start out about 100# lighter than the stated weight, then "progress" from there.

Fourth, you can experiment with the air spring. Definitely try adding a few pounds (maybe 220+) before ordering a new spring.

Fifth, you didn't mention how much sag you're getting. With the Stratos, depending on your riding style you should sag anywhere from 10-50% of stroke length. For XC riding, probably less than 25%. (My manual just recommended 50%, but the guy I talked to at Stratos said he runs 10-15% sag for XC riding. That would be too stiff for me).

Finally, even with heavy springs, the Marzocchi Z1 is a very "soft" fork, so to balance it out, you're going to need a soft rear shock.

Hope this helps. I'm still torn as to whether I should get a 300, 350, or 400# spring. I really wish I had an LBS that carried Stratos and would let me try out different springs without buying them!

[Old Proflexer]

matno -

you're only 140?

from your pic, it looks like your left arm weighs 140 all by itself!

OP

[Matno]

That particular arm probably does weigh 140. I borrowed most of that pic from "Commando" (Arnold Schwarzenegger). Only the face is actually mine...



(Besides, my AR-15 doesn't have a grenade launcher...yet!)

[keen]

 Re: My previous bike was a 97' Proflex beast. The suspension wasn't too active. I ride XC pretty much as you describe- occasional rock gardens etc. I rode the Stratos on a Mountain cycle San Andreas and it felt too soft on that bike. I havn't hit the trails w/ the Disco Monkey but based on the sag, 3/4", and the identical feel of the Mountain cycle I'd say it is too soft. I am not worried about bottoming the shock as I rarely jump but the pedal effort is too high- boucy, springy, soft??? I thought Stratos designed the shock to run a progressive coil because it has an air chamber to balance the soft start of a prog. coil? I would imagine 1/2" sag would be in order. I guess the prog. coil and air chamber gets me a little confused. I plan on going to a 600 prog. but wonder how it might work w/ a linear spring. If someone could just say don't use a linear the shock was designed for a prog. coil i'd be confident in choosing the 600 prog. Thanx

[IFO]

FOX vanilla Rc...


[smiley=laughing.gif]

with a 650lbs spring... all the shock you'll ever need...

[GrimJack]

The shock was definately designed for a progressive spring, but that doesn't mean it actually works better with one!

The Monkey with a properly setup shock on the back should feel a lot more active than the Beast did.  Pedal bob and such will become an issue unless you move over to one of the new technology shocks, like the 5th element or Romic.  This is just the way things are, riding a bike with 6 inches of rear wheel travel will includes a fair bit of bob.

Adding air to the Stratos will increase the spring a little at the beginning of the stroke, and a lot at the end of the stroke.  A stiffer spring will add across the board.  Air is cheap.