What pressure should me front forks have?

marcel147

[*]Hi all, need a little advice on setup.

Am riding a 2009 Boardman pro fs with standard fox forks. I would like a little advice on a correct psi or range that I should put in my forks.

I'm 15.5 stone & riding down stairs towpaths & moorland. Just finding front forks too sof on full lock even.

waby1234

That's a subjective one I think - try experimenting with higher pressures if it's too soft, but only go up in small increments. It depends on so many factors but I aim for about 25% sag when sitting on the bike and then adjust from there.

cooldad

Measure sag in 'attack position', ie out of the saddle, as if you are riding a bumpy section. Not sitting down.

marcel147

Reba rockshox forks - sorry was going off memory:)

Anyhow, they had 135psi in. I just looked on fork side and psi is shown for different weight ranges. For a 90kg + man, they should have 135+ psi. Shouldn'y have. Been to far off.

Upped to about 180psi, stood off bike and with hands on grips and feet off ground & leaning over bars with all my weight, forks locked out, I'm pressing the measuring ring to about 20mm from top of forks.

It's not quite "attack position" but hoping it will do...

EH_Rob

I'd completely ignore the psi charts, set them up for what feels right (20% sag or so). 180 is pretty high in my view. For what its worth I weigh about 75 kilos and have them at about 105 psi.

There is a second chamber that should be inflated to about the same psi as the top chamber. You can find the valve in the bottom of one of the fork legs.

cooldad

marcel147 wrote:

Upped to about 180psi, stood off bike and with hands on grips and feet off ground & leaning over bars with all my weight, forks locked out, I'm pressing the measuring ring to about 20mm from top of forks.

It's not quite "attack position" but hoping it will do...

No, they should not be locked out.

bennett_346

marcel147 wrote:

Upped to about 180psi, stood off bike and with hands on grips and feet off ground & leaning over bars with all my weight, forks locked out,

Come on, common sense man, how is that going to show you the sag?

marcel147

bennett_346 wrote:

marcel147 wrote:

Upped to about 180psi, stood off bike and with hands on grips and feet off ground & leaning over bars with all my weight, forks locked out,

Come on, common sense man, how is that going to show you the sag?

Ahh keep yer sarcasm dude, I don't know what I'm doing hence I'm on here pal.

bennett_346

Yes but, locked out? What did you think that would achieve? Lock out is so called for a reason.

marcel147

EH_Rob wrote:

I'd completely ignore the psi charts, set them up for what feels right (20% sag or so). 180 is pretty high in my view. For what its worth I weigh about 75 kilos and have them at about 105 psi.

There is a second chamber that should be inflated to about the same psi as the top chamber. You can find the valve in the bottom of one of the fork legs.

Thanks rob, I've only been dealing with bottom chamber, 180psi in there is my current situation.

Will have to look at top chamber too then. Tks

cooldad

All in here
viewtopic.php?f=40073&t=12629675

marcel147

cooldad wrote:

All in here
viewtopic.php?f=40073&t=12629675

Appreciated cool dad:)

marcel147

Read and understood ss's guide but I'm unfamiliar with "sag" would somebody please help me to understand the sag?

Thanks in advance

cooldad

Sag is the amount the fork sags when loaded, so the amount it compresses when you get on.
Measured by how much of the travel is taken up when you get on as a percentage.
So measure how much it sags using the rubber ring, or if there isn't one, stick a small cable tie around the stanchion.
If the travel is 100mm, and it sags 20mm, that's 20% sag, etc.
Assuming the Boardman has 120mm forks, you want sag of around 30mm (25%) to start, then experiment.

marcel147

Thankyou cooldad, that's got me fully sorted I think. Off out for a quick test & hope I dont go over the bars like earlier today:)
Its good to be able to fine tune the forks at last