hi guys pretty new to trials and have bought a 05 txt pro 280 and just replced the rear shock link bearings. i noticed the preload collar was wound up as hard as could go, and forks seem pretty soft just wondering how most riders have their suspension set as im assuminng you would need some sag and also enough compression and rebound to help bounce the bike around but not too much as the tires bounce off things and loose grip? any help on sag and settings would be great also the damping and rebound.

cheers chris

this might help...

https://www.youtube.com/watch?v=hpN4Iix_fkQ

Edited April 3, 201511 yr by michael_t

Rear spring wants to be 140mm long with the bike supported under the bash plate and the wheels off the ground Set the damping screw to middle and back both fork adjusters fully out

spot on cheers guys will have a go with it today and see how i get on.

Remember the best suspension setting is one that works equally front and rear. Test by pushing down in the middle of the bike. Better too soft than too hard. Never have seen marzocchi fork settings turned full out.

Remember adjusting the spring length only raises or lowers the ride height, it does not alter the stiffness or softness of the shock only a stiffer or softer spring can do that.

Edited April 4, 201511 yr by the addict

Remember adjusting the spring length only raises or lowers the ride height, it does not alter the stiffness or softness of the shock only a stiffer or softer spring can do that.

This is wrong! Preloading the spring will change the effective spring rate.

With the bike on the ground with no rider I aim for about 1/2 to 1 inch of sag at the rear guard. It should not be locked out with no sag and anything more than an inch you are loosing movement and upsetting the balance of the bike.

Edited April 5, 201511 yr by faussy

It preloads, thas why its called that way, lol. But if you use pre load to compensate you belly or a too weak spring, you will have less travel in your suspension.

more info...

https://www.ohlins.eu/en/motorcycle/technics/Setting-up-your-Bike-part-2-spring-preload--3554/

and another decent explanation of preload...

http://www.worksperformance.com/html/tpl_desc.html

i had a play with the bike yesterday, got the rear shock to sag correctly and feels pretty good but as for the forks they feel a lil on the soft side, a screwed the compression in to firm them up and didnt seem to do anything so think i might have to pull them in bits and service them :/

i had a play with the bike yesterday, got the rear shock to sag correctly and feels pretty good but as for the forks they feel a lil on the soft side, a screwed the compression in to firm them up and didnt seem to do anything so think i might have to pull them in bits and service them :/

The marzocchi forks arent very responsive to their screw adjustment. If you are a relative beginner id find it a tad unusual the forks are too soft for you. Dont worry if you are using most of your movement over smallish obstacles, trials suspension is a fair bit softer than road or motocross suspension.

However a bike that age could be more than due an oil change, old oil will reduce the damping and make it feel soft. Can be a bit of a pain on the marzocchis. If they still feel to soft for you you could make up a pastic or alloy spacer to go between the top of the springs and end cap to preload the spring about 1/2 inch (if you dont fancy buying new springs), although to reiterate, ive never really known anyone to want to harden the marzocchi forks, beginner and expert alike.

ah right this seems to make sense then, as i have done road and motorcross andvrealised im using pretty much all the travel at the front doing stuff. might do just a servive anyway as it cant do any harm. didnt realise the suspension was run quite soft as i thought you would want it not too soft when you are pushing up and down and bouncing around. just thought you would use a lot of energy in the suspension, maybe i just need to get fit haha. thanks for the info.

ah right this seems to make sense then, as i have done road and motorcross andvrealised im using pretty much all the travel at the front doing stuff. might do just a servive anyway as it cant do any harm. didnt realise the suspension was run quite soft as i thought you would want it not too soft when you are pushing up and down and bouncing around. just thought you would use a lot of energy in the suspension, maybe i just need to get fit haha. thanks for the info.

I know its pretty obvious, but run as soft as you can unless you feel it bottoming. You need it soft to grip over the small stuff like wet tree roots and the like and the bounciness actually helps for any lifts or hoping you may be doing, as you are using the rebound to do this. Any big hits is usually taken up by the rear if your body positioning is correct.

and#160;

This is wrong! Preloading the spring will change the effective spring rate.

and#160;

With the bike on the ground with no rider I aim for about 1/2 to 1 inch of sag at the rear guard. It should not be locked out with no sag and anything more than an inch you are loosing movement and upsetting the balance of the bike.

No, YOU are wrong. Spring rate is mesured in N/mm and you can't change that no matter how far you turn up the pre load.

 

"Spring Pre-load and spring rate - CHANGING PRE-LOAD DOES NOT CHANGE SPRING RATE. You don’t get a stiffer spring by adding pre-load. Rather you change the weight point at which the spring starts to move. Once the spring starts to compress it will move at its spring rating."

 

http://www.worksperformance.com/html/tpl_desc.html

On 9/19/2015 at 6:01 PM, guys said:

No, YOU are wrong. Spring rate is mesured in N/mm and you can't change that no matter how far you turn up the pre load.

 

"Spring Pre-load and spring rate - CHANGING PRE-LOAD DOES NOT CHANGE SPRING RATE. You don’t get a stiffer spring by adding pre-load. Rather you change the weight point at which the spring starts to move. Once the spring starts to compress it will move at its spring rating."

 

http://www.worksperformance.com/html/tpl_desc.html

Hence the word "effective"....