RockShox SID World Cup - Tech Q

[Brighter-Lights]

Just to add to the replies that came in while I was typing. Long ago, I also thought the STD recommendetions were waaayyy too hard, but if your fork feels too hard pumping the STD recommendations, there's too much oil in the damper in the right leg. Do a simple test by removing the lockout, damper top cap, and then pull the compression damper out slowly while twisting. Turn the bike sideways and dump, into a cup, a little of the oil. Put it back again and test.

 

If your fork is not locking out 100% as also said above, there's too little oil in the damper. When locked out, and taking a big hit, with thresold set hard, oil could also leak past the top stop/seal and get trapped in the upped part. So do the same as above, put back together. I'll make sure again, but I think I put 127ml of oil in the right leg.

[Markdeep]

Just to add to the replies that came in while I was typing. Long ago, I also thought the STD recommendetions were waaayyy too hard, but if your fork feels too hard pumping the STD recommendations, there's too much oil in the damper in the right leg. Do a simple test by removing the lockout, damper top cap, and then pull the compression damper out slowly while twisting. Turn the bike sideways and dump, into a cup, a little of the oil. Put it back again and test.

 

If your fork is not locking out 100% as also said above, there's too little oil in the damper. When locked out, and taking a big hit, with thresold set hard, oil could also leak past the top stop/seal and get trapped in the upped part. So do the same as above, put back together. I'll make sure again, but I think I put 127ml of oil in the right leg.

 

you make a good point about the Oil in the damper in the right leg, shot for all the Info, thought I was the only one struggling with this and feel more comfortable that guys say the standard settings are way too hard!

 

Will check it all out tonight and let you know

[Johan Bornman]

Hi,

 

Can anybody running these forks or know about these forks assist me with a tech Q. This being a dual air version, you have both the + at the top and - at the bottom. According to the little print on the shock it says for my weight 81-90kg I should be running at 120psi on + and - . When I try this setting it is SUPER hard, you literary have to put your body weight on it to make the shock engage. So in normally riding it rattles my hands badly. Now if I soften it to like 70psi and + and - then it feels right.

 

The reason I say this, is on my brothers Bike he has a RockShox Recon Silver which is a single Air, when I add the correct pressure for my weight the shocks feel 100% and so do other air shocks I have tested.

 

I suspecting something may be wrong with this fork, any ideas or should I just send it in for a service? The fork is still quite new though, done less than 100hrs..

 

Thanks in advance

 

Remember that pump pressure gauges vary wildly. I mean wildly. I have several pumps and can't believe any one pump.

 

I'll reply to some of the other responses but in a nutshell, set your sag correctly and I think your shock will be 100%.

[Johan Bornman]

 

Oil level in the right (damper) leg partly determines the amount of compression needed (in the left leg) to make the fork ride around the chosen sag percentage mark. On new SIDs is very easy to 'monitor' sag by looking down at the calibration marks while riding. IMO, setting sag as recommended by most, leaning against a wall while sitting on the bike doesn't give an accurate measurement as initial stiction plays an important role here and could result in a 'false' setting.

 

 

No, no, no, no. Oil level (unless far too much and it starts to limits compression, has nothing to do with sag. Nothing.

 

Cut cut cut cut.

 

 

Let me explain... The SID Races had too much oil in the right leg, adding to the compression curve and recommended pressures on the left leg were way too hard for my 70kg... At that time I pumped new SIDs rider weight over rider weight, + or - a bit at the negative chamber. But... after replacing all the oil in the right leg and adding to the correct level, the indicated pressures were much more realistic for good riding fork, hitting 80% travel on harder hits.

 

No. The compression curve is purely a function of the size of the air chamber - provided you're not again preventing compression completely by a hydraulic lock from too much oil. However, the two phenomena are not the same. Too much oil equals lockout and no further compression. The compression curve is determined by the amount of air your start with and the size of the air chamber and the ultimate compression cavity at the end of the stroke. It has NOTHING to do with the oil level on the other size. Provisors apply.

 

 

 

cut cut cut cut cut cut

 

1) with the bike standing upright, drop some fork oil, or even gearbox oil - 1 or 2 drops on the front side of the stanchoin (about 30mm above the wiper rim) and let it run down to the rim of the wiper, and then backwards of the wiper, (fork is at an angle so oil wil slowly run downwards to the back of the wiper) compress and release the fork once - dirt hidden on the edge of the wipers will have lifted and sit on the stanchoin - wipe off with soft cloth. Repeat 3-5 times. This will clear most of the crud, and also lubricate the stanchoins to some degree.

 

 

I disagree. This will do nothing to clean the area below the wipers. Yes, it will lubricate the crap that is in there, but best practice would be to clear it via opening and cleaning.

 

 

If the fork's upper bushes and foamrings were dry, this step will dramatically increase fork response

 

 

On the contrarary...but perhaps you know this and it is a typing error.

 

 

 

remember that any kind of resistance adds to the spring rate = harder feel with the same air pressure.

 

 

 

No no no. Spring rate has nothing to do with resistance at the stanchions or anywhere else or that matter. The very word "rate" refers to something per something. In this case it is travel per kilogram of applied mass. Unless the resistance is ludicrously high, the spring will travel the same distance on a dirty or clean fork for a given applied mass.

 

 

2) deflate + and - air, set rebound and compression damping to the least amount possible - make sure it's UNLOCKED! and cycle the fork up and down... This should be totally stiction free, and check how much travel the fork achieves when compressed all the way.

 

 

Your method is fine here but skip the stiction-free bit, we're not in outer space. Friction, taxes and *** TV are facts of life.

 

 

 

If the fork doesn't achieve at least 95% travel, something is in the way. That could be too much oil in the right leg (damping) or too much oil in the lower legs (lubricating) and oil can't compress - with these forks, it's very important to have the foam rings soaked + having enough oil in the lowers for lubrication - if THAT is properly maintained, the forks feels like your're floating on air. Very fast responding and smooth through the travel. Next...

 

 

Before we go to next....

 

Your methodology here is sound but I'd like to add one more possibility and that is too much oil on top of the air piston. This effectively reduces the compression chamber and creates ramp-up that prevents the fork from compressing all the way.

 

 

 

3) Remove the valve cores with a core removal tool and make sure they are good and sealing. A negative that's leaking may also make the fork feel VERY VERY hard, as you esentially have i.e. 100 top, 0 bottom. Then pump the + chamber to 100, and then the negative to 95 psi. When doing this, it's VERY important - crucial, to properly detatch the pump nozzle, as air can very easily leak out when detatching. In case of the negative, which is a very small chamber, a quick psssssst can be 30% of air in it.... resulting in a false impression of pressure inside... you pump it 100 and leak 40% and think it's 100... in reality, the underinflated negative will make the fork feel MUCH too hard. I use a Risse Racing pump with seperate atachment chamber which cannot leak air while taking it off... many pumps work like this.

 

 

It has to be a very poor pump to do this. Most pumps will just relieve the air trapped between the air hose and shock valve. The psst you hear is air escaping from the pump itself. The shock's valve seals immediate by the fact that the pressure on the outside is less than what's inside. I hope I understand you correctly here but a pump that opens the shock's valve by air pressure cannot leak pressure from the shock when unscrewing the pump.

 

 

 

 

First do the above and make very sure your pump is ok and that you're not spilling air while detatching the fitting... especially at the negative, because a 100 psi + 100 psi negative, which lost 30% while detatching, will make the fork feel MUCH harder than 100...

 

 

I agree about your negative pressure remarks but I think most decent pumps wont present with this problem. Maybe I'm naive and there are some really crappy pumps out there?

[Trapper]

Nope boet. That's the way a SID rides. Rock hard. I replaced mine with a Fox F120. Much softer ride.

 

That's why it's a ROCKshock...