emil Posted August 21, 2011 Report Share Posted August 21, 2011 I've been searching on sag settings in many threads and now I'm very confused. Many people are recommending this article by Jon: http://www.gasgas.com/Pages/Technical/trials-suspension-tips.html. The strange thing is that Jon says to adjust the race sag for the front forks to 1/6 of the total travel, but almost every thread in this forum says that 1/3 is the measure to go after. It's a big difference between 1/6 and 1/3, what value should I try to adjust the forks to? The total travel is 177 mm and the race sag is 43 mm with zero preload, somewhere between 1/6 and 1/3. Is that a good value, or should I adjust it? Another confusing thing is that my rear spring seems too soft. My bike is a GasGas 300 Raga -08. I've read that this bike is build for about 70-80 kg. My weight is 65 kg so the spring should be to hard for me. To achieve 1/3 race sag at the rear suspension I have to preload the spring to the bottom. With maximum preload the static sag will be around zero. Do I need a stronger spring even if my weight is bellow 70-80 kg? I really appreciate all help I can get to solve my problems. Quote Link to comment Share on other sites More sharing options...
lowbrow Posted August 21, 2011 Report Share Posted August 21, 2011 I'd be inclined to set the rear up with just a hint of static sag (say 5 - 10mm of movement before the wheel leaves the ground when you lift the back of the bike) and then see if the suspension compresses evenly when you adopt a riding position and bounce on the pegs. Your weight should be fine for the standard springs. Are you saying its too soft or have you just become concerned after reading a technical article? Its all a matter of personal preference at the end of the day. Quote Link to comment Share on other sites More sharing options...
emil Posted August 21, 2011 Author Report Share Posted August 21, 2011 I've only been riding trial for a year now. I haven't adjusted the suspension at all to this point. Now I want to start adjusting my suspension, and that's from a good starting point. I will check static sag tomorrow. What race sag should I start with at the forks (1/3 or 1/6)? Quote Link to comment Share on other sites More sharing options...
emil Posted August 22, 2011 Author Report Share Posted August 22, 2011 The static sag is zero at the rear, when race sag is 1/ 2.5. To achieve 5-10 mm static sag, the race sag will be far from 1/3. Should I adjust the static sag and don't care about the race sag? I appreciate all the help I can get! Quote Link to comment Share on other sites More sharing options...
jimmyl Posted August 22, 2011 Report Share Posted August 22, 2011 What is race sag? Quote Link to comment Share on other sites More sharing options...
emil Posted August 23, 2011 Author Report Share Posted August 23, 2011 Race sag is measured when you are standing on the bike with all riding gear. This link explains it better: http://www.gasgas.com/Pages/Technical/trials-suspension-tips.html Should I post this thread in "general trials talk" or somewhere else? I thought this was a common problem. Quote Link to comment Share on other sites More sharing options...
jse Posted August 24, 2011 Report Share Posted August 24, 2011 I've been searching on sag settings in many threads and now I'm very confused. Many people are recommending this article by Jon: http://www.gasgas.com/Pages/Technical/trials-suspension-tips.html. The strange thing is that Jon says to adjust the race sag for the front forks to 1/6 of the total travel, but almost every thread in this forum says that 1/3 is the measure to go after. It's a big difference between 1/6 and 1/3, what value should I try to adjust the forks to? The total travel is 177 mm and the race sag is 43 mm with zero preload, somewhere between 1/6 and 1/3. Is that a good value, or should I adjust it? Another confusing thing is that my rear spring seems too soft. My bike is a GasGas 300 Raga -08. I've read that this bike is build for about 70-80 kg. My weight is 65 kg so the spring should be to hard for me. To achieve 1/3 race sag at the rear suspension I have to preload the spring to the bottom. With maximum preload the static sag will be around zero. Do I need a stronger spring even if my weight is bellow 70-80 kg? I really appreciate all help I can get to solve my problems. My experience is that static sag is generally only useful as a starting point to measure race sag. Race sag is the "operating mode" of your suspension, and as such, sets the conditions under which your damping system works. The reason for my advice being different for forks and shocks is they are different systems with different variables. The shock usually works well at 1/3rd and not 1/6th is because you need to factor in the "rising rate' spring loading caused by the linkage. The ratio of the shock shaft travel to the rear axle travel is not linear, but exponential i.e. the shock shaft speeds up with a constant rise in the axle level. The shock operates in a relatively constant set of vertical forces but the fork has a lot of stuff going on that affects it's operation like weight transfer/bar pressure, steering geometry-rake/trail/offset etc., side forces, shock preload, blah, blah, blah. Given the choice of correcting the forks or the shock settings, I'd say get the rear set first. A lot of riders spend a lot of time fiddling with the forks and tend to forget about the shock. In my experience, the main reason I'm wiggling the bejezez out of those handlebars is to make the rear tire go where I want it, not just try to steer through the section. The back tire gives you traction and drive. Shock preload also (affecting race sag) has a lot of influence on how a bike steers as it affects the "trail" measurement. Before you jump for a new spring, try setting up what you have first. Recommended suspension settings are just advice as to where to start and are not carved tablets handed down from some mountain, so don't be afraid to experiment a little to see what suits your riding style. I don't think that 65 kg. would be totally outside the spring range you have. Poke around with your settings and see what you find, but try to change only one thing at a time as it takes a bunch of experience to accurately evaluate the effect of multiple variables. I wouldn't worry too much about making a mistake, your bike will tell you when you've gone too far with a setting. Jon Quote Link to comment Share on other sites More sharing options...
emil Posted August 24, 2011 Author Report Share Posted August 24, 2011 Thanks Jon for a good answer and a good article! I will follow your advice and try to test till I find a good solution. I just thought it was strange that I had to maximize the preload of the shock to obtain 1/3 race sag. Quote Link to comment Share on other sites More sharing options...
nzralphy Posted August 24, 2011 Report Share Posted August 24, 2011 1/3 front and rear every time. Quote Link to comment Share on other sites More sharing options...
emil Posted August 24, 2011 Author Report Share Posted August 24, 2011 Even if the preload is maximized? My manual says that the total stroke front is 177 mm and 164 mm rear. Then sag should be 59 mm front and 55 mm rear. I measure from the rear wheel axle, vertical to the rear fender. To achieve 55 mm at the rear, the shock preload must be compressed to its bottom. This seems strange when my weight is 65 kg and the bike is designed for over 70 kg. Quote Link to comment Share on other sites More sharing options...
jse Posted August 25, 2011 Report Share Posted August 25, 2011 1/3 front and rear every time. 1/3rd race sag works too. It will help tighten turning ability at the cost of straight-line stability. The reason I like a little more preload on the front is that the rider can affect a greater load shift on the front through the bars than just through the pegs like the rear (butt not on seat, which would change the angle of force). You have to be careful when measuring race sag. The rider must, of course, have riding gear on, but the rider must be in the position that reflects how the bike is ridden in a section and that means the appropriate pressure on the bars and upper body placement. Total weight of the rider/gear, how tall the rider is and upper body mass have an influence on how the front end is set up. Jon Quote Link to comment Share on other sites More sharing options...
emil Posted August 25, 2011 Author Report Share Posted August 25, 2011 When reading threads about race sag, everyone seems to agree that 1/3 is a good adjustment for the shock. The forks seems to be somewhere between 1/3 and 1/6. Do people use to have the preload nearly maximized to obtain 1/3 at the shock on Gasgas bikes? For me it seems like the spring is too soft when the preload has to been maximized, but that might not be a problem? I can add that I had the exact same problem on my previous Gasgas 125 -07. I am very careful when measuring sag and I have done it before on some enduro bikes without problem. I'm sorry for questioning a lot of question on this topic, but I really want to know how it works. Quote Link to comment Share on other sites More sharing options...
nzralphy Posted August 26, 2011 Report Share Posted August 26, 2011 Nope. 1/3 sag front and rear with your gear on and the bike is static. Get a friend to help and take the measurement a few times to be sure it is right. and check it every 6mths. Quote Link to comment Share on other sites More sharing options...
jse Posted August 27, 2011 Report Share Posted August 27, 2011 Nope. 1/3 sag front and rear with your gear on and the bike is static. Get a friend to help and take the measurement a few times to be sure it is right. and check it every 6mths. My guess is that we're actually in agreement. My recc' for 1/6 is for no weight on the bars so that the peg weight only is the static setting (which is the most consistant and repeatable setting) and when in riding mode (with weight on the bars) it should be in the 1/3rd range. I don't think we specified rider position when measuring race sag. Jon Quote Link to comment Share on other sites More sharing options...
gasser_david Posted August 30, 2011 Report Share Posted August 30, 2011 Just an observation..but it appears strange that the manufacturer has no detailed recommendations regarding both static and riding gear sag or damping set up. Given the importance of such adjustments upon the handling of the bike..very strange that gasgas don't highlight the importance of getting such settings as correct as possible...as can make a big difference to handling and 'feel'. My old 1991 KTM EXC 300 owners manual devotes numerous A4 pages to sag and rebound/compression damping in different conditions i.e sand and mud etc. plus 'fault finding' info. for handling problems.... so KTM obviously appreciated the importance of getting the settings right ... 20 years ago!!! As delivered from new it handled like a 'sack' ... utter rubbish. Once set up to my weight / body position etc. change was the proverbial night & day. From memory and 'scibbled notes' my TXT 200's settings for riding gear/body position sag are - Rear = about midway between 1/4 and 1/3 i.e. 28-30%. Damping just lighter than mid point. Front = about 1/4 i.e. 24-26% no doubt due to my running more than normal 'forks through top clamp dimension' which obviously 'quickens' steering amongst other things. Damping +2 click compression & -3 click rebound with 2.5 wt oil. Although as Jon points out ... weight on bars is not 100% repeatable on a consistent basis. FYI - not a hopping & a bopping expert..so above suits my old fashioned riding style..may be absolute rubbish for you. Glad to see that I don't appear to be too far off using trial and error adjustment method to obtain settings that I use. Suppose I should recheck them at some point as last done over a year ago. Hope this helps your search for perfection.... david Quote Link to comment Share on other sites More sharing options...
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