You are hereForums / By Discipline / Mountain (off road) / MTB Gear / Upgrade Stumpy to Enduro

Upgrade Stumpy to Enduro

Andy Bloot's picture

By Andy Bloot - Posted on 04 February 2008

Hello all fountains of information.
A way in the future (depending), but I'm interested in any advice on the following:
I have a Stumpy 120 (Septune 120mm Fox shock) with a 140mm fork
After recently cactusing the shock link I had it replaced with a beautiful piece of engineering that allows the rear end 120-150mm of travel.
The bike shop said that they couldn't get 150mm of travel from the back as it would throw out the geometry of the bike.
What I'm wondering is, to upgrade the bike to 150mm travel (Enduro) what would I need to do? Could I fit (say) a fox DHX air shock (is this a good choice?) and a 150 or 170mm fork (suggestions)?
The measurements of the Sepatune is 7.5'' x 1.75'' - I can't find another shock on the Fox site with these m'ments. They are all 2''. Can it be fitted using reducers, and would it fit the frame anyway?
If it is possible, am I confined to a certain max. amount of travel at the front.
Are there any other modifications or other issues I need to be aware of?
Thanks for any advice.

Stuart M's picture

won't be the shock.
Using the 150mm option would actually raise the back end of the bike relative to the head angle, swapping brands of shocks won't change this, and if you go to a different size shock it would only make the problem worse or negate that extra 30mm.

You need to be looking at a longer fork to match the extra height the back now has and on the face of it yes a 150mm fork would sound right.

Down side of this is that if you lift the front end to match the raised rear end you will actually also lift your standover height. This is good in helping clear obstacles but bad because it lifts your centre of gravity.

MAte its a shame to see you got that extra length up rear but can't use it. Why don't you just throw it on the 150 and give it a try with the existing fork. If you don't like the feel then swap it back until you get the bigger fork.

Hope this helps.

delicious's picture

Mods like this can invite disaster however if you're really keen I'd say install a new shock.The extra stroke of a quarter inch which is only 6mm shouldn't cause any suffering.190mm x 50mm is a common size.Buy which ever brand you fancy.Some brands will require new reducers though.The actual travel available will be hard to calculate as it's a math equation based on leverage ratios etc and I'm no mathematician....
Also,to start off keep your forks and see how you feel.Unless you're bottoming out often which tells you you're using all available travel and begging for more then don't worry yourself.
Once built,fool around with set up,meaning handle bar height relative to the ground and stem lengths.A short stem of say 70mm can do wonders for that real freeride feel and you'll bee able to jump and land easier,climb pretty well and quicken the steering.You'll feel a bit more in your bke.
If you got a new fork then set up your bike in the same way.Bar reach,position and height from the ground and hand position relative to the front axle are all important.Then get your seat position right.In any case,a fork over 160mm would be a disaster but up to that level one could find good set up without throwing out geometry to a degree to induce vomiting while your new suspension happily works beneath you.
Spending money on quality suspension upgrades is totally worth it.Nothing will make your bike ride,track and perform better.Bling parts may be nice,but suspension changes can be truly beneficial,but one must be really anal about set up.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Best Mountain Bike