scorpa3 Posted September 11, 2008 Report Share Posted September 11, 2008 If ground clearance, mudguard clearance, stability and suspension travel are ignored. Does sliding the fork tubes up allow the bike to make a tighter turning circle? Quote Link to comment Share on other sites More sharing options...
dan williams Posted September 11, 2008 Report Share Posted September 11, 2008 Yes Quote Link to comment Share on other sites More sharing options...
copemech Posted September 12, 2008 Report Share Posted September 12, 2008 No! (waiting) Quote Link to comment Share on other sites More sharing options...
jse Posted September 12, 2008 Report Share Posted September 12, 2008 (edited) No! (waiting) Your wait is over......yes. No, maybe, hmmm, let's see, front end weight bias: Wf=Wt(L-x)/L Wf=front-end weight Wt=total weight x=distance from front axle to CG L=wheelbase Well, Copey, I think it does in my experience. Jon Edited September 12, 2008 by JSE Quote Link to comment Share on other sites More sharing options...
copemech Posted September 12, 2008 Report Share Posted September 12, 2008 Your wait is over......yes.No, maybe, hmmm, let's see, front end weight bias: Wf=Wt(L-x)/L Wf=front-end weight Wt=total weight x=distance from front axle to CG L=wheelbase Well, Copey, I think it does in my experience. Jon You may be correct in reality, yet remember we are negating other factors basically, which only leaves the change in wheelbase, and the result of the drop, of say 6mm, just how much is that going to change wheelbase? Err' uh my mind says roughly 2mm. You will never make that turn Jon, it in itself is a totally negledgable factor, you are screwed! And the CG is not a constant, nor is Wf, they are dependant as the rider position changes which is centered on the pegs aft of CG. I postulate that if you did this same scenerio in 3 dimentions, a similar 6mm change in lean angle of the bike would yield you a more signifigant change in turning radius than the steering angle. Go run that through your 3D animation and let me know if you can make that turn? I need another beer now! Quote Link to comment Share on other sites More sharing options...
scorpa3 Posted September 12, 2008 Author Report Share Posted September 12, 2008 You may be correct in reality, yet remember we are negating other factors basically, which only leaves the change in wheelbase, and the result of the drop, of say 6mm, just how much is that going to change wheelbase? Err' uh my mind says roughly 2mm.You will never make that turn Jon, it in itself is a totally negledgable factor, you are screwed! And the CG is not a constant, nor is Wf, they are dependant as the rider position changes which is centered on the pegs aft of CG. I postulate that if you did this same scenerio in 3 dimentions, a similar 6mm change in lean angle of the bike would yield you a more signifigant change in turning radius than the steering angle. Go run that through your 3D animation and let me know if you can make that turn? I need another beer now! No wonder I couldn't make up my simple mind if it made any difference! Effects on the other factors (ground clearance etc) are pretty well established, however the actual turning circle query takes some working out. I'm going to try an experiment on some fresh wet ground. Keep the lean and body position constant (as far as is possible) and do one turn on max lock. Then repeat with raised forks starting from exactly the same place. Will the diameter of the circle left by the front tyre be different? I wouldn't put money on it...... or would I? Quote Link to comment Share on other sites More sharing options...
nzralphy Posted September 12, 2008 Report Share Posted September 12, 2008 Interesting... Yes it will turn tighter. But only by a couple of mm. Leaning the bike further into the turn will make it turn much tighter. 6mm will make the steering angle steeper buy approx 0.16deg. You may as well be talking about nothing and tyre pressure or spring settings will have more effect on steering head angle. It is likely to effect the feel of the handling of the bike and how the front would either tuck under or plow forward. But again tyre pressure and spring settings will effect things more The biggest difference i found is that the bars will be lower which suits some riders more. Quote Link to comment Share on other sites More sharing options...
tombo46 Posted September 12, 2008 Report Share Posted September 12, 2008 You lot are way too clever, it should be illegal. Tom Quote Link to comment Share on other sites More sharing options...
zippy Posted September 12, 2008 Report Share Posted September 12, 2008 Oh screw it just learn to hop the front and rear tire around..........takes less thinking. Quote Link to comment Share on other sites More sharing options...
motofire Posted September 12, 2008 Report Share Posted September 12, 2008 I dont think raising the forks up would be worth it. Yea it would turn a little tighter....but the front end would plow a lot more in the turns. Quote Link to comment Share on other sites More sharing options...
scorpa3 Posted September 12, 2008 Author Report Share Posted September 12, 2008 I don't want THIS I would like THIS Quote Link to comment Share on other sites More sharing options...
jse Posted September 12, 2008 Report Share Posted September 12, 2008 You may be correct in reality.......... Hmmmmm, what other way is there? This is a very interesting question, but darn difficult to answer objectively as there are so many other variables involved. My subjective experience is that it tends to make tight turns a little easier but it could only be that it's the placebo effect working and I only "feel" that it does. In Trials we seem to have more physical ability to effect steering geometry than, say, roadracing and the surfaces we face with the bikes are much more varied than just about any other sport, so it could be that the slight change in the fork height/tripleclamp area is not primary but results in a secondary effect, like more front weight bias dropping the tubes further into the lower legs and effecting the rake measurement. Copey, I breathlessly await your astute, three-beer final analysis of the question..... jon Quote Link to comment Share on other sites More sharing options...
nzralphy Posted September 12, 2008 Report Share Posted September 12, 2008 The bloke on the tractor has more hair than the dude holding the girl. It is therefor scientifically proven that tractors are better. Quote Link to comment Share on other sites More sharing options...
zippy Posted September 12, 2008 Report Share Posted September 12, 2008 NZRalphy Posted Today, 02:46 PM The bloke on the tractor has more hair than the dude holding the girl. It is therefor scientifically proven that tractors are better. And the tractor won't complain if he rides a different tractor tomorrow. Quote Link to comment Share on other sites More sharing options...
steveo Posted September 13, 2008 Report Share Posted September 13, 2008 I don't want THISI would like THIS Thats a nicely lowered fork leg, I would like that one too ! Quote Link to comment Share on other sites More sharing options...
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