Uprgading suspension travel

mr.tradesman

hi i've got a Whyte t-120 and im looking to replace the fork and shock from 120mm to 140mm+

will it be fine do this and do i need to cut the steerer and/or take headset spacers out?

thanks

nicklouse

so you want to slacken your steering by a degree?

that is not upgrading it is changing your geometery.

what is the current fork and whay do you want to change it?

mr.tradesman

i don't particularly mind about slacker steering but i've suggested cutting the steerer and/or taking the headset spacers out: wouldn't this steepen it and balance it out?

it is upgrading because i'm looking to buy a more capable, more expensive suspension fork and shock at the same weight; so i can absorb more impact (rather than bottoming out at 20% sag) while keeping the xc capability that the standard 28lb weight delivers

mr.tradesman

*current fork: rockshox reba rl

looking to gettinf fox 140 rlc

supersonic

You cannot alter the rear suspension, it works around specific geometry.

You could fit a longer fork, but check frame warranty.

mr.tradesman

annoying...

just checked and it voids the warranty...

...

nicklouse

mr.tradesman wrote:

i don't particularly mind about slacker steering but i've suggested cutting the steerer and/or taking the headset spacers out: wouldn't this steepen it and balance it out?

No it would do nothing at all. Same as if you did it your forks now nothing would change. Other than your grips would be lower.

Angles etc remain unchanged.

cooldad

What's wrong with the Reba - excellent fork. Maybe play with settings a bit rather.

nicklouse

cooldad wrote:

What's wrong with the Reba - excellent fork. Maybe play with settings a bit rather.

And/or get them serviced.

YeehaaMcgee

mr.tradesman wrote:

so i can absorb more impact (rather than bottoming out at 20% sag)

Sounds like you need to adjust the damping, rather than change forks.

Greer_

mr.tradesman wrote:

i don't particularly mind about slacker steering but i've suggested cutting the steerer and/or taking the headset spacers out: wouldn't this steepen it and balance it out?

it is upgrading because i'm looking to buy a more capable, more expensive suspension fork and shock at the same weight; so i can absorb more impact (rather than bottoming out at 20% sag) while keeping the xc capability that the standard 28lb weight delivers

Sounds like you need more pressure in it too.

YeehaaMcgee

20% sag sounds fine. But compression damping should be increased if he's expecting it to handle big hits.

mrmonkfinger

YeehaaMcgee wrote:

20% sag sounds fine. But compression damping should be increased if he's expecting it to handle big hits.

can you do that on a reba?

YeehaaMcgee

Depends what reba, surely. I'm sure changing the oil is possible in any model though.
But, what I'm getting at is that increasing the pressure is not the way to prevent bottoming out. The damping system is what controls the fork's travel.

mrmonkfinger

YeehaaMcgee wrote:

But, what I'm getting at is that increasing the pressure is not the way to prevent bottoming out. The damping system is what controls the fork's travel.

quite so

bails87

mrmonkfinger wrote:

YeehaaMcgee wrote:

20% sag sounds fine. But compression damping should be increased if he's expecting it to handle big hits.

can you do that on a reba?

On my Reba Race (2008) and Rev RLT Ti (2011?) you just turn the blue dial on the right hand fork leg to adjust the compressin damping.

The Rookie

YeehaaMcgee wrote:

But, what I'm getting at is that increasing the pressure is not the way to prevent bottoming out. The damping system is what controls the fork's travel.

Are you saying that increasing pressure won't help at all? As it certainly will, if you're asking a shorter travel fork to take big hits, just upping the damper can leave it unresponsive over extensions, you match damper rate to spring rate on any suspension system, so while it will work OK within a certain 'window' go outside that and if you up the compression damping rate you should up the spring rate and therefore the rebound rate to suite each other.

YeehaaMcgee

The spring rate is not the right way to go about reducing bottoming out. End of.

styxd

Yes, if you increase the pressure then you wont be able to set the sag correctly.

supersonic

Thoough it does depend on the ramp of of the fork, many air forks will ramp up and some designs use this to prevent bottom out. In some boxxers they use a system called Drop Stop (an adjustable elastomer) to control bottom out.

The Reba has compression damping with a blow off adjuster (on most models). This effectively makes it low speed compression and is not really designed for massive hits.

mrmonkfinger

I've just looked up this fork.

Is it a dual air version?


£5 says the air chambers aren't balanced right.

supersonic

Rebas are yes. Except very rare OE ones.