emil Posted August 31, 2011 Author Report Share Posted August 31, 2011 Thanks David for a good answer. I've also had some enduro bikes, latest was a KTM EXC 200 -08. Like you say, in enduro there is plenty of information regarding suspension. With good suspension settings on an enduro, it's much easier to ride faster. I'm a beginner at trial, but I know the importance of suspension. That Quote Link to comment Share on other sites More sharing options...
gasser_david Posted August 31, 2011 Report Share Posted August 31, 2011 Hello Emil Should have added the comment about linkage and swingarm bearings been in 'tip top' shape..no binding or play..before doing any type of set up. Seen plenty of trials bikes with around 20mm (3/4 inch) of free play at wheel due to linkage bearings been well worn... Regarding your linkage 'problem'..obviously will have some effect when riding...but when bike on ground any 'play' / 'slop' in linkage will be taken up.. and shouldn't effect difference between static and 'race sag' measurements...unless you measure static sag with rear wheel off ground..then it will make a difference. To quote Bill Clinton...depends on what your definition is...of static sag in this instance... Once had a 87 (I think) Beta TR34 200 where the previous owner had tightened linkage bolts far too tight so that badly binding...which made rear end feel way overdamped and the bike a 'total dog' to ride... as rear end reluctant to move.. so did make a difference....unfortunately I wasted several hours trying to sort it out before I realised what the real problem was. Yet again a reluctance by manufactures to freely give torque settings for linkage bolts etc... which I consider to be important david Quote Link to comment Share on other sites More sharing options...
emil Posted September 1, 2011 Author Report Share Posted September 1, 2011 I always start by measure total distance with both wheels off the ground. Then I measure static and race sag from that point. In my case, free play in linkage will affect the results. It seems like the linkage worn out pretty fast on Gasgas. My bike does still have the original chain, but the linkage is loose and mowing about 20 mm. I agree David, torque settings should be included to every new bike. Quote Link to comment Share on other sites More sharing options...
gasser_david Posted September 1, 2011 Report Share Posted September 1, 2011 Having read my last post...I don't think I made the point clear..not helped by a few beers!! So I'll try again.... Bike on box..rear wheel off ground..in your case you can lift wheel up & down due to linkage play of 20mm. Lift wheel until play taken up and pack with a wood wedge which takes out any play....then make 1st measurement. Stand bike on ground and take 2nd measurement....which should give static sag. Get on bike..bounce a couple of times with usual riding stance and take 3rd measurement...which should give race sag. Over the years I have fully rebuilt my linkage a couple of times with all new parts and even then there is still a small amount of play...which is why I use the wood wedge method to eliminate play from calculations. Hope this makes sense to you david Quote Link to comment Share on other sites More sharing options...
cabby Posted September 1, 2011 Report Share Posted September 1, 2011 Having read my last post...I don't think I made the point clear..not helped by a few beers!! So I'll try again.... Bike on box..rear wheel off ground..in your case you can lift wheel up & down due to linkage play of 20mm. Lift wheel until play taken up and pack with a wood wedge which takes out any play....then make 1st measurement. Stand bike on ground and take 2nd measurement....which should give static sag. Get on bike..bounce a couple of times with usual riding stance and take 3rd measurement...which should give race sag. Over the years I have fully rebuilt my linkage a couple of times with all new parts and even then there is still a small amount of play...which is why I use the wood wedge method to eliminate play from calculations. Hope this makes sense to you david That all makes sense to me, you now have three measurements - check.... Now what ? Oh and sorry for jumping in, been following this closely. Quote Link to comment Share on other sites More sharing options...
emil Posted September 2, 2011 Author Report Share Posted September 2, 2011 A few beers make things a little harder (or easier)... That was a good solution! I will try that next time when I have measurement help in the garage. Quote Link to comment Share on other sites More sharing options...
gasser_david Posted September 2, 2011 Report Share Posted September 2, 2011 Hello Thedbf Measurement 1 - Measurement 2 = Static sag Measurement 1 - Measurement 3 = Race sag or what I call 'riding gear' sag as done wearing helmet & boots etc which makes me slightly heavier... When making measurements remember that wheel follows an arc...so I measure from wheel spindle center to a point on rear mudguard at the 11 o-clock point on the LHS so avoiding silencer on RHS. Hope this helps david Quote Link to comment Share on other sites More sharing options...
cabby Posted September 2, 2011 Report Share Posted September 2, 2011 (edited) Gonna take this to PM to save any further embarrassment for myself...PM coming your way G D Edited September 2, 2011 by Thedbf Quote Link to comment Share on other sites More sharing options...
emil Posted September 3, 2011 Author Report Share Posted September 3, 2011 That all makes sense to me, you now have three measurements - check.... Now what ? Oh and sorry for jumping in, been following this closely. I can really recommend this link: http://www.gasgas.com/Pages/Technical/trials-suspension-tips.html Quote Link to comment Share on other sites More sharing options...
moleman Posted September 4, 2011 Report Share Posted September 4, 2011 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. Getting back to your first post... if you have to adjust the spring all the way down at your weight it may be that you have lost some or all the pressure in the shock, the pressure can contribute 1/4 to 1/3 of spring pressure (in effect) it may show symptoms of oil loss on the shaft or rubber bumper, if you loose all pressure it will leak, as the pressure inside makes the seal work, but it is possible to loose some pressure and still seal. what make of shock is it and does it have a valve? check against another similar bike, and see how far their adjuster is down. Quote Link to comment Share on other sites More sharing options...
emil Posted September 5, 2011 Author Report Share Posted September 5, 2011 Ok. I thought the mechanical spring did absorb all static loads. It Quote Link to comment Share on other sites More sharing options...
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