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  1. #1
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    27.5 rigid fork on 26er

    Hi to all and please advice.
    I have 26 Stevens F10 and would like to swap RS Tora SL 130mm with some rigid fork and 27.5 thick tyre /2.6 2.7 or 2.8 .
    Would this fork be ok:
    https://www.aliexpress.com/store/pro...70b07c4cBEEs3d
    Last edited by dawor; 4 Weeks Ago at 01:51 PM.

  2. #2
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    I think that rigid fork is going to be too short.

    That fork has an axle to crown of about 440mm. Your fork that you're taking off is about 510mm. You'll want to roughly calculate how much height a 27.5 tire adds, and then find a fork to offset that amount. I think the one in the link is an inch+ short.
    WTB: Med Bontrager Ti Lite, PM Me...

  3. #3
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    Which model Trek 26er is that?

  4. #4
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    Kona P2 29er fork will work fine. I've used it in place of 150mm Rockshox Sektor on my 26er before.

    My favorite is the Identiti Rebate XL though.

  5. #5
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    27.5 rigid fork on 26er-imag0963-1-1_zps5caa25eb-picsay.jpg

  6. #6
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    This is my bike,I would like to go rigid on front with a thick tyre.
    What do You suggest?
    Attached Thumbnails Attached Thumbnails 27.5 rigid fork on 26er-112755128.vxxvuxaz.jpg  


  7. #7
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    Quote Originally Posted by jestep View Post
    I think that rigid fork is going to be too short.

    That fork has an axle to crown of about 440mm. Your fork that you're taking off is about 510mm. You'll want to roughly calculate how much height a 27.5 tire adds, and then find a fork to offset that amount. I think the one in the link is an inch+ short.
    You need to take sag into account. A 130mm fork should sag about 40-45mm in attack position, so you have to subtract that from the axle-to-crown of the suspension fork.

    There is 25mm diameter difference between 27.5 and 26” wheels. So assuming a similar tire width, 510-42.5-12.5=455mm. Since a suspension fork sags a bit more in the corners, 440mm is just about perfect.

  8. #8
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    Quote Originally Posted by dawor View Post
    This is my bike,I would like to go rigid on front with a thick tyre.
    What do You suggest?
    What do you consider thick? Are you replacing your front wheel with a larger-than-100mm fat hub? Are you staying with 26” or going 27.5?

    CarbonCycles.cc has a wide variety of carbon and aluminum forks, and their 445mm 26” forks will fit a 26”x3” tire, and I’d bet a 27.5x2.8” would fit, if not larger. They also have 465mm that will fit about anything, and fat forks but they are probably too tall. You’ll need to make sure the steerer will fit the head tube (1 1/8” or tapered), and that the axle fits (quick-release or through-hub).

    Carver Bikes have some nice forks too (some of which are almost identical to the CarbonCycles forks), but less selection.

    I own one of each and can recommend both.

  9. #9
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    Quote Originally Posted by banjor View Post
    You need to take sag into account. A 130mm fork should sag about 40-45mm in attack position, so you have to subtract that from the axle-to-crown of the suspension fork.

    There is 25mm diameter difference between 27.5 and 26” wheels. So assuming a similar tire width, 510-42.5-12.5=455mm. Since a suspension fork sags a bit more in the corners, 440mm is just about perfect.

    OK I'm really missing something here. The sag has nothing to do with what tire will fit into what fork, because the fork and arch are at fixed distance around and over the tire; the distance is fixed between the top of the tire and the bottom of the fork arch whether he sits on the bike or not. If that was not the case, people who used all of their fork length would be banging into the front tire all the time. Remember that he's talking about the largest tire INSIDE the fork, not anything from the fork arch up to the crown. The moving parts in the fork don't affect what tire will fit in the fork. All that matters is the width and height of the tire inside the current and proposed fork, nothing else.

    Dawor: I like your posts. You bring up interesting information. I'm going to do the same thing to with my 26" later. However, after looking at rigid 27.5" forks that start at around $125, I decided that since air forks are so damn cheap, I'll do that instead. Some 27.5" forks can't take a 2.8 tire so you may want to play it safe and first try 27.5 x 2.60 or 27.5 x 2.75 instead (I cannot find any 27.5 x 2.70). Or...you keep your 26" fork and do a 26 x 2.70, that will probably fit.
    ABSU: Arrogantly executing mythological occult metal since 1991.

  10. #10
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    Quote Originally Posted by richj8990 View Post
    OK I'm really missing something here. The sag has nothing to do with what tire will fit into what fork, because the fork and arch are at fixed distance around and over the tire; the distance is fixed between the top of the tire and the bottom of the fork arch whether he sits on the bike or not. If that was not the case, people who used all of their fork length would be banging into the front tire all the time. Remember that he's talking about the largest tire INSIDE the fork, not anything from the fork arch up to the crown. The moving parts in the fork don't affect what tire will fit in the fork. All that matters is the width and height of the tire inside the current and proposed fork, nothing else.
    There are two things to consider: will the tire fit, and does the fork/tire combination match the geometry of the frame? You are only considering whether the tire will fit. Remember that most suspension forks have a lower fork brace that limits tire size (except Cannondale Leftys), but most rigid forks have no bridge and can fit a larger tire.

    The tire size, fork height, and sag all matter because they change the height of the head tube/handlebars/top tube and even pedal height. The geometry of a particular frame is set up for a combined fork/tire height. A frame that is designed for a 120mm fork is going to ride too high and with too shallow a fork angle with a 150mm fork. Similarly, if you replace the tire with a larger tire, that will also bring the front end higher. You compensate by using a shorter fork. This is why most 29” bikes have less fork travel than their 26/27.5” counterparts.

    You may not think it matters to raise your front end by an inch or two, but it not only affects height but also fork angle. Increased height and decreased angle both make steering worse, and you end up with a front end that wanders, especially when going uphill.

  11. #11
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    Quote Originally Posted by banjor View Post
    There are two things to consider: will the tire fit, and does the fork/tire combination match the geometry of the frame? You are only considering whether the tire will fit. Remember that most suspension forks have a lower fork brace that limits tire size (except Cannondale Leftys), but most rigid forks have no bridge and can fit a larger tire.

    The tire size, fork height, and sag all matter because they change the height of the head tube/handlebars/top tube and even pedal height. The geometry of a particular frame is set up for a combined fork/tire height. A frame that is designed for a 120mm fork is going to ride too high and with too shallow a fork angle with a 150mm fork. Similarly, if you replace the tire with a larger tire, that will also bring the front end higher. You compensate by using a shorter fork. This is why most 29” bikes have less fork travel than their 26/27.5” counterparts.

    You may not think it matters to raise your front end by an inch or two, but it not only affects height but also fork angle. Increased height and decreased angle both make steering worse, and you end up with a front end that wanders, especially when going uphill.

    This is why I'm thinking of putting 26+ tires on my 27.5". So you are saying that geometry-wise, a 26+ tire in front and a 27.5 standard in back would be better than the reverse? I'm going to try both but just wanted some opinions first, theoretically speaking. I put a standard 26 on the front already and it rode OK but it was not quite as stable downhill. Hopefuly a 26+ will fix that but we'll see.
    ABSU: Arrogantly executing mythological occult metal since 1991.

  12. #12
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    Quote Originally Posted by chelboed View Post
    Click image for larger version. 

Name:	IMAG0963-1-1_zps5caa25eb-picsay.jpg 
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    Is that photo with a 26" front wheel? Do you think the Rebate XL would fit a 26x2.8???

  13. #13
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    Just ordered a Identity Rebate 14/20 XL fork. I hope it will solve my Hugo 52 26+ clearance issues...

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