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  1. #1
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    120mm fork on Mach 4?

    I'm looking at building up a M4 this winter. Just read an article where the magazine reccommended a 120mm over 100mm fork on the M4, they say it makes the bike more "Usable over a wide variety of terrain"

    Is anyone using this setup?
    Can you comment how it affects the handling of the bike?

    Thanks in advance...

  2. #2
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    I used to have a Mach 4 that I purchased with a 120mm fork. It was great, except that I preferred to set my bike up for steep climbs and dropped it to 100mm to help keep the front end down. That was the only drawback to having it at 120mm. If you are climbing normal stuff I'd go for 120mm to make it more versatile.

  3. #3
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    Quote Originally Posted by rtcage
    I used to have a Mach 4 that I purchased with a 120mm fork. It was great, except that I preferred to set my bike up for steep climbs and dropped it to 100mm to help keep the front end down. That was the only drawback to having it at 120mm. If you are climbing normal stuff I'd go for 120mm to make it more versatile.

    Thanks for the repy, was the tendencie of the front to come up so bad that you could not slide forward to the front of the seat to overcome it?

  4. #4
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    Sliding forward helped for almost everything except for stuff that most people couldn't make it up in the first place. I would go with the 120mm since you can lower it to 100 pretty easily if you ever want to. My guess is that you will leave it where it is.

  5. #5
    West Chester, PA
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    I have a small with a 120, a 90mm stem and a setback post. For me it happened because i wanted a stiff frame with a firm pedal platform and a shorter wheelbase than the stumpjumper it replaced. In reality I could have possibly gotten a medium but i prefer a slightly smaller frame for the perception of control and flickability. I ride with a more sloppy bmx style - using the whole trail, manualing between gaps and rollers, hucking off roots and rocks. For my style, its perfect. If you're more of a true cross county rider who tends to keep the rubber on the ground you might like it better with the shorter fork.

    You lower the head tube angle 1 degree with a 120. The front end can wander on me a little during very steep climbing. Usually reminding myself to get my ass on the nose of the seat fixes that.

    Here's my comments from march right after i first got my frame -

    Quote:
    Originally Posted by with_the_band
    Hey 92gli, how does it ride (and climb)?

    I've just been demoing a mach 4 and was thinking about getting one and putting a 120 fork on it but run the stem as low as possible to make up for the extra hight.



    Its great. I think the longer fork and reduced head angle really fit what I need the bike to do. Its handling the short steep climbs we have in my area very well, the power transfer to the rear wheel is so much better than the specializeds I had. On the decents its just slack enough to give me most of the stability that the stumpjumper had, but with a much shorter rear end - which makes it very easy to manual.

    When I first got the frame a had 22.5mm of spacers between the HS and stem. The stem is a 6 degree bontrager. I started that way because it gave me the same handlebar height as I had with the stumpjumper. On the first ride I was having some trouble keeping the front wheel down on the very steep short climb I use as my benchmark. I now have only one 5mm spacer between the hs and stem and I was back on that climb last friday and the front wheel stayed down.

    Keep in mind, if you get a bike built up with a 120mm fox fork and you don't love it you can easily reduce the fork to 100mm. But, IIRC, the 100s can't be increased to 120 safely because the inners aren't long enough.

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