Woom Off cassette swap. 11-40 Sunrace- Mtbr.com
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  1. #1
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    Woom Off cassette swap. 11-40 Sunrace

    Hi, I am contemplating a Woom 5 Off for my sons next MTB (hes currently on an Islabikes 20 pro.)
    I keep looking at other options. It seems hard to justify to pay triple for a Trailcraft, and all the rest are so much heavier.

    The only thing Id like to improve in the Woom is the low gearing (stock is 9-speed, SRAM X5, 11-34.)
    I think an 11-40, 9-speed Sunrace cassette would be a cheap and easy drop in. Am I right? Has anyone done this change?

    Thanks!

  2. #2
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    I bought a Woom Off 5 for my son. If I remember correctly, the shortest gear is short enough even for tough climbs (I cannot find the chainring size at the moment)

    If you do want to change the cassete, you need to verify that the derailleur can handle a 40T largest cog.

    I usually like to upgrade and customize my bikes, and my kids' bikes, and if possible - to build them myself. Becasue of this, my only problem with the Woom Off 5 is that it's too perfect - I have nothing to upgrade there . . .

    Really - the bike is light, has proper gears, wide rims and tires, great brakes, good ergonomics. I'm planning to add a dropper post, and even then it'll weigh 9.5kg.
    Last edited by oren_hershco; 02-07-2020 at 10:30 AM.

  3. #3
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    Update: I checked my son's Off 5. The chairing is 28T.

    This gives a short gear almost identical to the 24x36 I have on my mtb (after calculating the wheel size difference)

    => Change nothing. Take the Woom off the box and go ride!

  4. #4
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    Quote Originally Posted by Encinitas Rider View Post
    Hi, I am contemplating a Woom 5 Off for my sons next MTB (hes currently on an Islabikes 20 pro.)
    I keep looking at other options. It seems hard to justify to pay triple for a Trailcraft, and all the rest are so much heavier.

    The only thing Id like to improve in the Woom is the low gearing (stock is 9-speed, SRAM X5, 11-34.)
    I think an 11-40, 9-speed Sunrace cassette would be a cheap and easy drop in. Am I right? Has anyone done this change?

    Thanks!
    Agreed with some of the other posters that gearing is probably OK with a 28T in front.

    If you're not going to be riding it immediately, the only thing I'd consider is waiting for the front suspension option -- I've seen a few references in reviews indicating it's supposed to be out in the spring.

    Would be curious to see what they eventually offer and if they'll make the fork available as an aftermarket part, since they're using 1" headsets and I don't really know of many suspension forks at that size.

  5. #5
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    Quote Originally Posted by TimTucker View Post
    Would be curious to see what they eventually offer and if they'll make the fork available as an aftermarket part, since they're using 1" headsets and I don't really know of many suspension forks at that size.
    Actually, it uses a 1 to 1 1/8 "baby taper" fork according to the specs on their web site. Ive never seen any suspension fork with this steerer type. Maybe the head tube can accommodate a more standard headset... Anyone knows the ID of the top and bottom of the head tube?

  6. #6
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    In this picture, you can see a kid riding a bike with a suspension fork in the background:

    https://cdn.shopify.com/s/files/1/22...g?v=1565615686

    It has a woom sticker on one side and a thru axle. I don't know what model it could be.

    On this picture of the stem, you get a better view of the top headset cup:

    https://cdn.shopify.com/s/files/1/22...g?v=1565609395

    The headtude probably has a 44mm ID. If that's the case, you could probably fit a straight 1 1/8" fork or even a standard tapered fork with an EC44 lower headset cup.

  7. #7
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    Thanks, oren_hershco

    Damn! "Change nothing" seems too simple!
    I know you are probably right, but I like to think I am doing something special...

    Ok, just so I have something to think about, is the chainring replaceable? What standard is it?

    And yes, I am going to wait for the suspension model to come out. I will probably still buy rigid, but woom kills it, maybe I'll be convinced.

  8. #8
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    Photos looks like a 4 hold pattern of some sort. If stock is a 28t, I'm guessing it's 64 bcd.

    If that's the case, you could try an oval ring - I just picked up a 26t one from Neutrino Components over in Russia. Nice touch is that you get your choice of color for anodizing.

  9. #9
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    It's some kind of a direct mount. The 4 bolts are for attaching the bash guard.

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