[descente]

i was doing some thinking the other day, which can be dangerous. a 8.75 shock with a 2.75 stroke compresses to 6" eye to eye. a 9x3 shock compresses to the same 6" i 2 i. this leads me to assume that the only difference between the two shock sizes is a .25" longer shaft. so why couldn't i install a longer shaft on my current shock to get more travel from my bike.

- my frame gets 7" of travel from an 8.75 x 2.75 shock
- fitting a 9x3 shock would net ~7.8" travel
- it is a very desirable but older frame that fits me well
- without the shock mounted, the swingarm gets 10+" of travel before linkage binds
- the shock i run is made by a major manufacturer, located in my city, and i have several friends who can raid parts piles for whatever i need.
- i can get really courageous with a dremel and move the upper shock eye hole on the frame .25" and not alter the static geometry with a longer shock, but gain more travel (which would do cool things like make it slacker and lower when i get on it). i know people did a similar mod with older DHRs to make them slacker and had no issues.

how dumb is this idea? do i fail at math and bikes?

 

[freeridefool]

You didnt say what frame, and that would help. But if it was my bike, and Im not afraid to cut and drill on any of my stuff, I would leave the 8.75 on it but still drill the upper shock mount to lower the bb and slacken the ha. You are going to make bigger gains in handling doing that, rather than gaining the extra .8 inches in travel.

I have a demo 8. Ive ridden a pretty similar demo 7 and didnt notice the travel all that much. Its really up to you though. But like I said if your sure it will clear and not bind or anything and wont eat your seat at bottom out I would go the route of slackening it.

 

[samdemo]

Who makes a 9"x3" shock? I thought 9.5"x3" is the standard for 3" stroke shocks. I know a few make a 9"x2.75".....


edit. I guess Avy makes a 9x3...

 

[descente]

i've seen quite a few actually. i think fox, elka, and rock shox all make them too. or the people who list classifieds don't know how to use a tape measure...

frame is a commencal dh supreme. the geometry is already pretty damn dialed as it is, but when it gets rocky you can definitely tell that it is 7" in back and 8" in front. its the older version with 73mm bb and 12x135 rear spacing. its hard to find info about the older versions of the frame but i think there was a version before the mk 2 (gees world champ frame) that got 8" travel, i could be wrong tho.

 

[Steve M]

9.0x3.0 is not a standard size... Elka do a 9.0x2.75, and 9.5x3.0, but nobody I'm aware of does a 9.0x3.0 (Avalanche might?).

 

[Wa-Aw]

i've seen quite a few actually. i think fox, elka, and rock shox all make them too. or the people who list classifieds don't know how to use a tape measure...

frame is a commencal dh supreme. the geometry is already pretty damn dialed as it is, but when it gets rocky you can definitely tell that it is 7" in back and 8" in front. its the older version with 73mm bb and 12x135 rear spacing. its hard to find info about the older versions of the frame but i think there was a version before the mk 2 (gees world champ frame) that got 8" travel, i could be wrong tho.

Putting a longer shock on you'd pay the price of kissing that dialed geometry goodbye.

 

[troy]

Putting a longer shock on you'd pay the price of kissing that dialed geometry goodbye.

To avoid that, You can run lower spring rate with more sag.

 

[norbar]

To avoid that, You can run lower spring rate with more sag.

That will then make the susp feel crappy if one does not like crazy sag.

I say ask the avy guys if they can get you a 8.75x3 shock. I remember they did some resizing (or was it someone else).

 

[descente]

Putting a longer shock on you'd pay the price of kissing that dialed geometry goodbye.

thats why i would move the upper shock mount .25" back to retain the same geo with a longer shock.

guess i was wrong about it being a standard size. i wonder if avy could make a 8.75x3. that would be perfect. and it would match my avy boxxer very nicely i bet....