[oddestfellow]

I just bought a MX Comp 120 for my Weyless SP 18" frame. I emailed Supergo to see if the 120 was going to be too long for the Weyless (probably should have done that first) and they said that the frame is designed to handle a fork up to 100 and that the 120 will throw off my geometry. Couple of questions - has anyone put a 120 on an 18" Weyless SP and if so, how did it work out? Also, is there a way to shorten the travel on an MX Comp 120 to 100?

 

[ANdRewLIu6294]

it probably would work fine, just affect the rake and the geometry of the bike

 

[dawgboy]

Personally, I don't think you will notice a difference except maybe on steep technical climbs and in that case, use the ETA!

 

[GearHead]

You will definitely notice a difference between a 100 mm and 120 mm travel fork on the same bike, completety different animal. However, you may like the way it rides better. One thing to note also is that some frames can't handle the extra stresses of a longer travel fork, it will cause the head tube to ovalize.

It is easy to change your fork from 120 mm to 100 mm. Here is a link to a lot of service manuals:

http://manualer.happymtb.org/marzocchi/

The 2004 Marzocchi manuals have good schematics showing the spacer which needs to be changed. Also, if the 120 mm spring is too stiff for you you actaully resuse it as a 100 mm travel spring and simply move the spacer to the top of the spring stack and it won't cost you anything.

 

[dawgboy]

Don't know about the Weyless but I have an 04 Kona Dawg which was designed for and came with a 100mm MX fork. I replaced it with a 120mm MX Pro (nice fork) to rake it out a little. I noticed VERY little difference between the two forks. Was almost disappointed! I did get a better ride however as I was able to lower the air preload a little and run with more sag. I do agree gearhead that a taller fork can make a big difference on certain frames but on the Dawg it did not. There is only 20mm difference axle to crown difference between these two fork so I wouldn't worry about ovaling your head tube. It's not like your going to a Z1 or something.

Try it if you don't like it, you can always go reduce the travel as gearhead said. Good link by the way

 

[GearHead]

Good link by the way

If go up one level in the directory you will see that there are manuals for a lot of MTB companies.

 

[oddestfellow]

You will definitely notice a difference between a 100 mm and 120 mm travel fork on the same bike, completety different animal. However, you may like the way it rides better. One thing to note also is that some frames can't handle the extra stresses of a longer travel fork, it will cause the head tube to ovalize.

It is easy to change your fork from 120 mm to 100 mm. Here is a link to a lot of service manuals:

http://manualer.happymtb.org/marzocchi/

The 2004 Marzocchi manuals have good schematics showing the spacer which needs to be changed. Also, if the 120 mm spring is too stiff for you you actaully resuse it as a 100 mm travel spring and simply move the spacer to the top of the spring stack and it won't cost you anything.

Thank you for the link! The fork I'm buying is the '05 - was there much of a difference between the '04 & '05?

 

[GearHead]

The '04 and '05 forks should be the same, they haven't made many recent changes. I think I wrote incorrect instructions before so here is a clarification.

Being you have the 120 and want the 105 mm version, you will not have the 105 mm version spacer already inside your fork. You can either buy this spacer or make one out of plastic pipe. Also, the preload spacer on top of the main spring stack will be approximately 15 mm too long as you need to lower the fork height by 15 mm. You can probably cut off part of the top preload spacer and use this as the spacer on the damping cartridge on the bottom.

Also note that if the 120 mm travel rated spring had the correct spring rate when being used as a 120 mm travel fork, it will now bottom out when used as a 100 mm travel fork. However, if the 120 mm rated spring was too stiff when used as a 120 mm travel fork, it will now work perfect as a 100 mm fork.