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Re: Riding in the wet

Posted: Wed Feb 06, 2008 9:16 am
by BJ
Just a couple of pics from last weekends Denman twinshock trial. It was tough weekend for the observers too :P

Re: Riding in the wet

Posted: Wed Feb 06, 2008 12:35 pm
by PA
I notice that the last rider is not wearing calf length boots of Leather or other suitable material.

Re: Riding in the wet

Posted: Wed Feb 06, 2008 2:58 pm
by outfit65
Riding in the wet?? What's that??
Here in SA we don't ride in the wet, unless a flock of galahs fly overhead, and we don't ride in fog either, unless dust counts!

Anyone got a feather hat, a tom tom and know how to dance?

Its a dry agruement!

Outfit

Re: Riding in the wet

Posted: Fri Nov 28, 2008 9:37 pm
by gordonmichaellee
Re begining of topic. check tyre presures.

Cheers Gordon

Re: Riding in the wet

Posted: Sat Nov 29, 2008 12:48 pm
by Trango
I have found out from trial and error that having the rear shock adjusted correctly for your body weight greatly improves grip.

Re: Riding in the wet

Posted: Sat Nov 29, 2008 7:01 pm
by Neo
Trango wrote:I have found out from trial and error that having the rear shock adjusted correctly for your body weight greatly improves grip.


Hi Trango,

How did you work out what the best settings for you were?

Best of balance.
Neo

Re: Riding in the wet

Posted: Sun Nov 30, 2008 8:15 am
by Trango
Hi Neo

I first realised the importance of suspension settings about 15 years ago when I bought a TT 350 Yamaha off a mate of mine. He was about 30 kg lighter than I was and I think now he had the shockie set too soft even for his weight. When I started riding it and opened the throttle I could feel the rear suspension pull down before before the bike moved forward. I started gradually adjusting the tension on the shock until the bike moved forward when the power was applied. The improvement in the acceleration and handling of the bike on enduro tracks and on the road was remarkable. When I returned to trials I used this experience as a guide when adjusting the too soft shockie on my trials bike and I noticed a difference in the grip I was getting. You do not want the shockie set too hard or you will lose the benefit of the full travel but if it is too soft the traction of the back wheel will be lost in the suspension. I cannot give you an accurate measure of where this point is as I go by trial and error when riding it but I will look at finding a measurement I can pass on.

Re: Riding in the wet

Posted: Sun Nov 30, 2008 8:28 pm
by David Lahey
The effect that Trango is referring to is the result of our bikes using chain drive to the back wheel.
Because the top run of the chain is under tension during accelleration, and the chain runs above the swingarm pivot, the tension in the chain tends to cause the swingarm to rotate upwards. The manufacturer positions the swingarm pivot to minimise this effect and is optimised for when the standard sprockets are fitted and the rear suspension rides at the height intended by the manufacturer. The weight of the rider, rear spring rate, rear spring preload, the length of the shock/ies and the diameters of the sprockets all will affect how close to ideal the setup is on any given bike for minimising the effect.
Be aware that in optimising a non-standard bike for this effect you may make it worse to ride in other ways. For example if you have a larger than standard sprocket (on either end or both ends), you may want to change the ride height to bring the top run of the chain back closer to the swingarm pivot to minimise the Trango XT350 effect. This would then also affect the steering geometry, centre of gravity and seat height.
If you have ever ridden a shaft drive bike you will have probably noticed the opposite happen (the rear end rises under accelleration).

Re: Riding in the wet

Posted: Sun Nov 30, 2008 9:01 pm
by Neo
Hmmm...interesting stuff... :-k

I will have test this out during the week :thumb:


Best of balance.

Neo

Re: Riding in the wet

Posted: Sun Nov 30, 2008 11:37 pm
by gordonmichaellee
I understand all that but I'm not sure you are right about the shaft drive. Please explain.

cheers gordon