HugovdMerwe Posted April 17, 2016 Share I feel strongly that any bicycle component manufacturer who uses O-rings (and bearings) should publish the sizes of these cheap industrial consumer items and not try and sell you a very expensive "seal kit". I recently serviced my Rockshox SID RL 100mm Solo Air 29" (was new at about 2013) and measured and recorded all the O-ring grooves. I post the O-ring sizes here for anyone's perusal: (The name used for the specific O-ring is as per Rockshox Service Manual from their website. As per standard O-ring notation, size in mm is given by Internal Diameter x Cross-Section).Top cap, air spring 25x2.5Seal head inner, air spring 10x3Seal head outer, air spring 21x3.5Top cap, compression damper 25x2.5Compression damper piston 23x2.5Outer seal head, Dig Valve 25x2.5 Get O-rings from bearing suppliers. They are very cheap, I once bought a 100 for R1.00! The O-rings above was about R1 a piece. Link to comment Share on other sites More sharing options...
David Marshall Posted April 18, 2016 Share Some fine tuning for the above :- These sizes apply to the other 32 mm RS models and to dual air. Damper side: Compression cartridgetop cap 25 x 2.5lower seal 22 x 2.5o'ring under lockout lever 13 x 1.8 (imperial 12.29 X 1.78) Rebound shaft outer seal 24 x 2.5 (actually imperial 119 ie 23.81 x 2.62)inner seal (omitted above) 12 x 3.5 (imperial 12.29 X 3.53) Air side:- top cap 25 x 2.5top piston 21 x 3.5lower piston outer 21 x 3.5lower piston inner 10 x 3 For some reason 21 x 3.5 are not easy to come by. I use 22 x 3.5 for the top piston and 20 x 3.5 for the lower. Crush washers: ID 8 mm OD 11 mm H 2 mm. Link to comment Share on other sites More sharing options...
BaGearA Posted April 18, 2016 Share ADIMIN'S PLEASE PIN THIS THREAD Link to comment Share on other sites More sharing options...
Skylark Posted April 18, 2016 Share Some fine tuning for the above :- These sizes apply to the other 32 mm RS models and to dual air. Damper side: Compression cartridgetop cap 25 x 2.5lower seal 22 x 2.5o'ring under lockout lever 13 x 1.8 (imperial 12.29 X 1.78) Rebound shaft outer seal 24 x 2.5 (actually imperial 119 ie 23.81 x 2.62)inner seal (omitted above) 12 x 3.5 (imperial 12.29 X 3.53) Air side:- top cap 25 x 2.5top piston 21 x 3.5lower piston outer 21 x 3.5lower piston inner 10 x 3 For some reason 21 x 3.5 are not easy to come by. I use 22 x 3.5 for the top piston and 20 x 3.5 for the lower. Crush washers: ID 8 mm OD 11 mm H 2 mm.Does the closest metric size work as well as the correct imperial oring? I got the orings incl the imperial from Skf. Link to comment Share on other sites More sharing options...
David Marshall Posted April 19, 2016 Share Does the closest metric size work as well as the correct imperial oring? I got the orings incl the imperial from Skf.Rule of thumb - a stretch greater than 5% of the O-ring I.D. is not recommended. Link to comment Share on other sites More sharing options...
Skylark Posted April 19, 2016 Share Rule of thumb - a stretch greater than 5% of the O-ring I.D. is not recommended.So I can substitute a metric oring for a imperial if the ID is within 5%, is that either way, I can go smaller or bigger. Link to comment Share on other sites More sharing options...
David Marshall Posted April 19, 2016 Share So I can substitute a metric oring for a imperial if the ID is within 5%, is that either way, I can go smaller or bigger.Yes but......... the problem is that it is difficult to find the original spec for the o-ring. You are never sure if the one in there was already adjusted at the previous service or not. I have even found slight variances in the agent supplied seal kits. Measuring the groove that the o-ring goes in will give you the ID but the width is more difficult to estimate as the ring will squash out sideways in the fork and groove but you cant say by how much. If the fork came in working I try to match the rings exactly. If you have to make a judgement you usually have a bit more leeway on the damper side. On the RS air side the lower 10 x 3 must be the right one. This is a common size so should not be a problem. The outer seal can vary (20,21,22 x 3.5) A word of warning - don't trust your supplier! Once you have the o-ring measure it yourself and then do an idiot check by resting it on top of the old one just to be sure. Then bin the old one so that you don't mix them up. Link to comment Share on other sites More sharing options...
Skylark Posted April 19, 2016 Share Agreed, I got sold the closest metric when I requested imperial, luckily I had a vernier with and checked before paying. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.