CurtisRider Posted April 22, 2011 Report Share Posted April 22, 2011 I am a little confused as to what spring I need for the rear of my marin. The shock is 19cm (7 1/4 inches)eye to eye The shock stroke is 5.5cm (2 inches) The spring is 5.5cm (2 inches) OD and 12cm (4.5inches) long The spring says (g400 550) on the side, i'm assuming its a 550lb spring, although that seems a little high so maybe its 400lb? The travel of the bike is 13cm (5inches) Even with the spring compressed as much as possible with the threaded washer thing, the suspension compresses halfway. I am nearly 15 stone, however aiming to be about 14. What spring do i need exactly? its for cross country use and id like a relatively stiff rear setup. I am thinking this spring in the 2" x 750 Llbs (For 190/200 Shock) size? Thanks in advance! Quote Link to comment Share on other sites More sharing options...
Christophe' Posted April 22, 2011 Report Share Posted April 22, 2011 This will pretyy much sort you out http://www.tftunedshox.com/info/spring_calculator.aspx Quote Link to comment Share on other sites More sharing options...
CurtisRider Posted April 22, 2011 Author Report Share Posted April 22, 2011 (edited) Thanks, I used that but its for the wrong shocks...will that make a difference? I just have a budget thing on there, but it works fine and seeing as I don't ride often, I cant justify changing! EDIT: the site seems to suggest a 600lb spring, does that sound about right? Edited April 22, 2011 by Paul Oliver Quote Link to comment Share on other sites More sharing options...
Tomm Posted April 22, 2011 Report Share Posted April 22, 2011 If you're getting that much sag, it'll probably either be a 400lbs spring, or a 550lbs spring that's ruined (old) and not as springy as it should be, hard to say. You'd never really feel the difference between 550lbs and 600lbs, unless as mentioned the 550lbs one was f**ked. The problem with springs is that they're really variable - depending on age / manufacturer one 550 spring can be completely different to another one. The only real way to get an answer is to try some different springs which isn't easy if you're buying online. Also what type of Marin is it? I'm not quite sure about the science behind it - but that website seems to suggest that single pivot / DW-link bikes should run softer springs than for 4-bar frames. Which is weird, because you can tailor a DW-link to have whatever combination of rising/falling rate you want, so I don't think they can generalise like that. So I don't know whether you should be using the values for Single Pivot/DW or VPP/4-bar. If it's one of those quad link bikes then it probably counts as VPP? The best way is to find out what other people are using on the same type of bike. I used that TF spring calculator for my Iron Horse and it came out with a 550 or something. I'm currently using a 400 which is spot on so I don't have too much faith in the calculator. P.S. Spring preload is bad. Tighten the collar until the spring stops rattling on the shock, then leave it. If it's too hard / soft, buy a different spring. P.P.S Are you definitely sure on the shock geometry. 200x50 is by far the commonest size for an XC bike rear shock. Quote Link to comment Share on other sites More sharing options...
CurtisRider Posted April 23, 2011 Author Report Share Posted April 23, 2011 Thanks for your help Tomm Its a Marin Rocksprings, quite an old frame, possibly 10years old? So its possible the spring is tired, however the frames in awesome condition so i doubt its been used much! The only reason im using the preload right now is to make the bike rideable, otherwise it would be nearly fully compressed all the time. I think the frame is 16-17 inch, so it would come with a soft spring for a lighter rider, so maybe 400lb is the correct spring weight. I really dont want to be spending much on this, as i dont use it often enough to justify it, so those £25 springs i linked would be perfect I havent really found much info on the frame, i wouldnt know which forums to search either Quote Link to comment Share on other sites More sharing options...
Tomm Posted April 25, 2011 Report Share Posted April 25, 2011 Well, since it's a very old frame and shock, it may well be a 550 that's old. At least the frame is single pivot which makes it slightly easier to judge. The TF tuned calculator recommends a 513 or 573 spring depending on what the shock is. Since it's old I have no idea which one it'll be but I'd err on the higher value since there probably won't be much compression damping built into the shock (which I guess accounts for the different values TF gives). I'd go for a new 550, I think. Give it a quick try on the bike and if it's completely wrong then send it back. Quote Link to comment Share on other sites More sharing options...
Shaun H Posted April 28, 2011 Report Share Posted April 28, 2011 Looks like the coils near the damping end are f**ked? They're much more bunched up than in the rest of the spring. Or is it a progressive rate spring? Quote Link to comment Share on other sites More sharing options...
craigjames Posted April 28, 2011 Report Share Posted April 28, 2011 Well i'd plump for a 550lbs (although using the Mojo spring weight calculator it suggests a 600lbs spring). As you're intending to lose some weight a 550 should be fine Quote Link to comment Share on other sites More sharing options...
CurtisRider Posted April 28, 2011 Author Report Share Posted April 28, 2011 Hi guys, thanks for your help, its very much appreciated. I think i will go for a 600lb judging by the results given on the sites as they seem to always suggest springs that are still on the soft side from past experience (had springs for my old pyslos and vanillas) Annoyingly it'll now be 5 weeks til i get to ride the bike again, so there isn't much point ordering just yet Quote Link to comment Share on other sites More sharing options...
CurtisRider Posted May 28, 2011 Author Report Share Posted May 28, 2011 (edited) Sorry to drag this up again... Seen this air shock for £50 This would mean i could adjust the shock as i please and it cant be any worse than what i have now i assume? EDIT: I am aware the bushes wont be included, i will make my own on my lathe Edited May 28, 2011 by Paul Oliver Quote Link to comment Share on other sites More sharing options...
Tomm Posted May 31, 2011 Report Share Posted May 31, 2011 Should be OK. It's 200x50 though which isn't the size you said earlier (although as I said, is the most common size). Air shocks feel a lot different to coils. Even a ruined coil shock may be more responsive on fast downhills, but the air shock is way lighter and far better for pedalling. Quote Link to comment Share on other sites More sharing options...
CurtisRider Posted May 31, 2011 Author Report Share Posted May 31, 2011 Thanks for the response Tomm, it occured to me after that it was 10mm too long, so i have found a few on ebay that are the correct size and hopefully cheaper (not like this is expesnive as such but i am on a pretty tight budget). I also realised that shock doesnt appear to have rebound adjust! Im not fussed about the suspension being ultra supple (i know air shocks arent reknowned for being as good as coils) as long as it takes the bigger hits, thats all i am worried about Quote Link to comment Share on other sites More sharing options...
CurtisRider Posted May 31, 2011 Author Report Share Posted May 31, 2011 Got this off ebay, should be superior to the Radium, and good enough for me Quote Link to comment Share on other sites More sharing options...
CurtisRider Posted June 7, 2011 Author Report Share Posted June 7, 2011 If anybody cares, i fitted the shock tonight and....WOW the bike is like a different machine now, so responsive and a pleasure to ride, its rekindled my love for biking again i cant wait to get riding! The shock is about.5mm from touching the seat tube of the frame, pretty tight! Managed to use the old bushing from the previous shock and the bushings from this new one, to cobble together the right bushings for the new shock to fit Now to give the frame a fresh lick of paint and the bike will look respectable! 1 Quote Link to comment Share on other sites More sharing options...
Tomm Posted June 7, 2011 Report Share Posted June 7, 2011 If anybody cares, i fitted the shock tonight and....WOW the bike is like a different machine now, so responsive and a pleasure to ride, its rekindled my love for biking again i cant wait to get riding! The shock is about.5mm from touching the seat tube of the frame, pretty tight! Managed to use the old bushing from the previous shock and the bushings from this new one, to cobble together the right bushings for the new shock to fit Now to give the frame a fresh lick of paint and the bike will look respectable! I think to change the colour would be a crime. Glad you got the shock sorted. Quote Link to comment Share on other sites More sharing options...
haydon_peter Posted June 7, 2011 Report Share Posted June 7, 2011 When I was younger I always used to love those Marins You could run the gear cable without that big loop of cable to the mech, Shadow mechs make cable routing much neater. And while I'm being picky, please do up your front QR with the lever ~180degrees from where it currently is and have it in front of the fork leg, I wouldn't want you catching it on something while hurtling down a trail Quote Link to comment Share on other sites More sharing options...
Tomm Posted June 8, 2011 Report Share Posted June 8, 2011 And while I'm being picky, please do up your front QR with the lever ~180degrees from where it currently is and have it in front of the fork leg, I wouldn't want you catching it on something while hurtling down a trail Yes! One of my pet hates. The QR needs to be on the other side for that though - the fork leg get in the way otherwise. Quote Link to comment Share on other sites More sharing options...
haydon_peter Posted June 8, 2011 Report Share Posted June 8, 2011 HAHA oh yeah, the QR lever should be on disk side too, that's a double QR fitting fail Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.