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  1. #1
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    Reputation: Stevob's Avatar
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    Rigid Fork Length for replacing 100mm Shock

    Is it 425mm or 445mm? I'd think 445, but just want confirmation from someone who's done it already. I can't find my tape measure to measure my fork. Help.

    edit, sorry. For 26" wheel.
    I see hills.

    I want to climb them.

  2. #2
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    Im also interested to know. Soon my old trek 4300 will become a single speed rigid urban/trail bike and it currently has a 10o mm on it also.

  3. #3
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    Sorry, I don't know 26" fork lengths. If you do measure don't forget to take sag into account.

    Anyway, I can offer this: you don't necessarily need to match the same height. You won't be flying downhill at the same top speed so its ok if your bike is a little twitchier at high speed with a shorter fork. Also, you will have to pick and weave your way through rock gardens and such so being able to turn a bit quicker can be a benefit. I switch between a 100mm suspension fork and an rigid fork that's the height of a sagged 80mm susp fork and also has a lot more rake (which makes it steer even faster). The quicker feel of that shorter fork goes great with the precise steering feeling of riding rigid

    EDIT: I did find this document from RockShox that summarizes axle to crown lengths for their forks. Subtract 20% of the travel to find an equivalent rigid fork length

  4. #4
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    Quote Originally Posted by boomn
    Sorry, I don't know 26" fork lengths. If you do measure don't forget to take sag into account.

    Anyway, I can offer this: you don't necessarily need to match the same height. You won't be flying downhill at the same top speed so its ok if your bike is a little twitchier at high speed with a shorter fork. Also, you will have to pick and weave your way through rock gardens and such so being able to turn a bit quicker can be a benefit. I switch between a 100mm suspension fork and an rigid fork that's the height of a sagged 80mm susp fork and also has a lot more rake (which makes it steer even faster). The quicker feel of that shorter fork goes great with the precise steering feeling of riding rigid

    EDIT: I did find this document from RockShox that summarizes axle to crown lengths for their forks. Subtract 20% of the travel to find an equivalent rigid fork length
    interesting, i cant wait to get a rigid on it. My only concern is the wide trek frams looking funny with a skinny little surly rigid or something.

  5. #5
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    I've ridden rigid before, but that was on a bike not designed for a suspension fork, a 1997 Giant Yukon.

    FWIW, the research I've done since has shown that 445mm is the popular choice to replace 100mm forks. I just wish I could find my tape measure.
    I see hills.

    I want to climb them.

  6. #6
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    Thanks for the document boomn, I found my fork on there and it's 471mm, so take a bit of sag off and 445 sounds right, but put a bit more compression into the picture, like in corners, it comes down further. So I suppose it's a bit suck it and see. I'd hate to loose grip on corners, so I might go for a 425mm and just live with the twitchyness.
    I see hills.

    I want to climb them.

  7. #7
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    20% of the travel is only 20mm, so by that reasoning, 445 would be closest.
    I see hills.

    I want to climb them.

  8. #8
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    Fireline 26er rigid option

    Anyone running a rigid (carbon or ti) fork on a 26er Titus Fireline? If so, opinions and specific length/offset are welcome.

  9. #9
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    I run a 445mm White Bro Carbon fork on my Scandal which is set up for a 100m fork, which is the correct length when taking into account sag.

  10. #10
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    How would a 445 mm fork work on a bike set up for a 80mm suspension fork?

  11. #11
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    FWIW I have a 438 mm Vicious which I've run on a Gunnar Rockhound (designed around 80 mm fork) and a RM Blizzard (80 or 100 mm) and that A-C length seems pretty good. It was actually racier on the Rockhound, less so on the Blizzard, if you can figure out where your frame geometry fits in relation to them...
    RIDE HARD, live easy.

  12. #12
    XCDude
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    would 445mm work on 29er designed for 100mm

    I am replacing my Reba 100mm with a rigid.
    I ordered an Exotic carbon 465mm, but they sent a wrong fork with 445mm.

    I am debating whether to return this and get the 465mm or just use 445mm.

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