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Discussion Starter #1
Hello all,

I have a suspension adjustment related question.

On our bikes, the stock suspension is only preload adjustable, and I understand that this will basically affect ride height (assuming linear springs). I?m about 170 lbs, and I?m wondering exactly what adjusting just the front and rear preload both together or separately will do to how my bike behaves. For example: lowing the front/raising the rear and vise versa?

Thanks
 

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heff said:
Hello all,

I have a suspension adjustment related question.

On our bikes, the stock suspension is only preload adjustable, and I understand that this will basically affect ride height (assuming linear springs). I?m about 170 lbs, and I?m wondering exactly what adjusting just the front and rear preload both together or separately will do to how my bike behaves. For example: lowing the front/raising the rear and vise versa?

Thanks
Some of the guys in the SV racing forum are really more qualified than myself to answer this, but, I believe it affects how much dive you get loading the suspension, and the static sag measurement. I could be wrong though.
 

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I'll take a shot at it... pre-load sets where the bike sits when there is no force going on, braking or accelerating (static sag). If it sits lower, you use less of your suspension's travel. If it sits too high, its possible to use too much where the forks extend too far or something like that. Overall I think the purpose is to have the bike set to the point that the suspension can be used to its best abilities.
 

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As well, changing ride height would change the center of the mass (you and the bike) which would effect cornering capability.
 

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fork preload essentially only changes ride height/sag..
 

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heff said:
Hello all,

I have a suspension adjustment related question.

On our bikes, the stock suspension is only preload adjustable, and I understand that this will basically affect ride height (assuming linear springs). I?m about 170 lbs, and I?m wondering exactly what adjusting just the front and rear preload both together or separately will do to how my bike behaves. For example: lowing the front/raising the rear and vise versa?

Thanks
Adjusting the suspension sag essentially puts the suspension in its ideal operating range. Rougly 30mm of sag is about 1/3 of the suspension's travel, so that it can dive/squat/take up bumps in one direction but also extend into dips (or extend the front under acceleration, or extend the rear under braking) in the other without topping out. The idea is to keep the tires in contact with the road.

Lowering the front quickens steering. Raising the front slows it. Most people do this by raising the forks up through the triple clamps instead of with preload so as not to take the suspension out of its proper range. Raising the rear will quicken your steering and decrease squat under acceleration. Lowering the rear does the opposite. Again, there are more ideal ways to do this than preload.

If your suspension is at the stock settings though, you probably have too much sag as it is. You should measure it.
 
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evilbologna said:
If it sits lower, you use less of your suspension's travel. If it sits too high, its possible to use too much where the forks extend too far or something like that..
other way around.
with less preload you use more travel and with more preload you waste part of travel.
 

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TWF said:
evilbologna said:
If it sits lower, you use less of your suspension's travel. If it sits too high, its possible to use too much where the forks extend too far or something like that..
other way around.
with less preload you use more travel and with more preload you waste part of travel.
doesn't it just move the travel from bottom to top?
 

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Discussion Starter #9
NOsquid said:
Lowering the front quickens steering. Raising the front slows it. Most people do this by raising the forks up through the triple clamps instead of with preload so as not to take the suspension out of its proper range. Raising the rear will quicken your steering and decrease squat under acceleration. Lowering the rear does the opposite. Again, there are more ideal ways to do this than preload.

If your suspension is at the stock settings though, you probably have too much sag as it is. You should measure it.
Thanks NOsquid! This is exactly the info I was looking for. I assume that quickening the front by lowering it, happens because you're reducing the rake and trail of the front? I was mostly just curious if I could tell a difference between the different preload adjustments on the bike. Sometimes it seems to wander a little bit and is very susceptible to following pavement sections etc (perhaps rear wheel alignment is out?). I will go measure the sag and will adjust accordingly.
 

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Wandering

Preload will affect straight line stability only if you have so little preload that the front end is too low when you are sitting on the bike. Proper preload is necessary, as mentioned above a couple of times, to put the suspension in the best part of its travel. This avoids bottoming out and topping out (within reason. You can always find bad enough roads to top or bottom out no matter what).

Set your preload, make sure the rear wheel is aligned properly, make sure the head stem isn't loose, make sure your tires are properly inflated, try again. If the front end still wanders then try pushing the forks down in the triple clamps 3mm and try again. Post back with results.
 
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RandyO said:
TWF said:
evilbologna said:
If it sits lower, you use less of your suspension's travel. If it sits too high, its possible to use too much where the forks extend too far or something like that..
other way around.
with less preload you use more travel and with more preload you waste part of travel.
doesn't it just move the travel from bottom to top?
kind.
let say you have about 1/2 inch of travel left in forks(they are not compressing all the way).with less preload you will end up using it.you did not move travel but you use more now.forks still extend all the way as before.
if you dial to much preload they are are not extending(they are already extended),you lost that part by preloading it.
 

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heff said:
I assume that quickening the front by lowering it, happens because you're reducing the rake and trail of the front?
Correct :) Raising the rear does that also.
 

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Discussion Starter #13
Re: Wandering

andyauger said:
Preload will affect straight line stability only if you have so little preload that the front end is too low when you are sitting on the bike. Proper preload is necessary, as mentioned above a couple of times, to put the suspension in the best part of its travel. This avoids bottoming out and topping out (within reason. You can always find bad enough roads to top or bottom out no matter what).

Set your preload, make sure the rear wheel is aligned properly, make sure the head stem isn't loose, make sure your tires are properly inflated, try again. If the front end still wanders then try pushing the forks down in the triple clamps 3mm and try again. Post back with results.
Well, there's traces of a hurricane here now, so I can't go try this immediately. I'll check sag ASAP; I do know tire inflation pressures are correct, and the rear wheel is aligned per the factory marks (will check using tape measure or some other technique soon). I've read the manual on checking the stem bolts (and searching around here) so that?s on the to do list also.

Thanks for all the input.
 
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