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  1. #1
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    BMX crankset on MTB idea help

    I am current riding single speed with a home modified single speed crankset and the freewheel fully intact, with no tensioners or derailers and both gear changers gone.I have bent many rear axels due to tension and alignment. Before i spend money on the following I was wondering if I put a BMX crankset on my mountain bike and replaced my wheels with 24" cruiser weight bmx wheels in horizontal drop outs, would i have to worry about chain alignment and/or tensioners? Don't judge! this was my long term goal for my bike anyways.

  2. #2
    the test dummy
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    bmx cranks

    i know u can put 3 peace cranks on a mountain bike you just need a different bottom bracket
    Quote Originally Posted by craftworks750
    Riding a mtb is like a reset button, 10 mins in and there is nothing else in the world that matters.
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  3. #3
    Ovaries on the Outside
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    This whole thing confuses me. Would you be using the bike on singletrack? I think 24" wheels would lower the BB too much, assuming you are putting the wheels on a 26" frame. And if you are putting a BMX wheelset on a mountain bike, the rear spacing is going to be all off.

    More details and then we can go from there....

  4. #4
    the test dummy
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    it wont work well it would but it want work good the cranks would hit and u would have no brakes
    Quote Originally Posted by craftworks750
    Riding a mtb is like a reset button, 10 mins in and there is nothing else in the world that matters.
    my bikes
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  5. #5
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    yeah i want 24"s on a 26" bike frame and i dont care if i have brakes or not what i did to my bike was took off the smallest and biggest crank and left the middle one cause its the one attached to my pedals and the frame. i took off the left gear cables and componets cause i now only have that one middle crank, so theres no need to shift when theres the one crank. I also took off the cables,gear shifter and derailer chain tensioner thing from the back wheel, i left the rear freewheel together and chose the gear i wanted it on and got a chain tool and made the chain smaller. so the chain goes from the one working gear (the 4th speed ,the middle one for allignment) on the 7 speed sprocket 26" rear tire to the single middle crank, so its kinda like a ghetto single speed. since 24" cruiser weight bmx rims come with only a single speed for the back tire i thought i could make it easy on myself and just get that,it would also make the bike lighter which i want. but the alignment with the middle crank would be off now. i would have to get a crank thats closer to the frame to line up with the single speed at the back cause its closer to the hub now on a 24' rim. i have broke many rear axels with this and before i get a new crankset and 24" wheels i want to know if it will work.insanitylevel9 are you saying that when i pedal they would hit the ground. that would just give me more reason to change the entire crankset.

  6. #6
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    i dont see how 24" wheels are making anything easier, it's super easy to convert over to a SS on a regular multi speed wheel. FAR easier than trying to go with a 24" wheel IMO.

  7. #7
    Ovaries on the Outside
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    I'm tapping out until there is more punctuation. I spent the last hour walking around my house running into things because my pupils exploded.

  8. #8
    Shred...it's the new drug
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    Ok, just get some profile cranks...so sick and lots of tuning options to get your chain line set just right. I run a set on my DH bike and planning to get some for the SS. Solid, proven and US made. Case closed...

  9. #9
    the test dummy
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    hey well good luck tell me how it comes out
    Quote Originally Posted by craftworks750
    Riding a mtb is like a reset button, 10 mins in and there is nothing else in the world that matters.
    my bikes
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    Ben

  10. #10
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    OP, i'm going to assume you're on a budget, that your rear wheel has a thread on multi-speed freewheel, and that your crank has a chainring that is integrated into the crank arm. a 24 inch wheel is not going to solve your problems, it's going to make you some more.

    my advice, take your bike to your local bike shop and tell them you want to convert it to single speed, and that you want to swap your crank for a bulletproof crank.

    they will remove your current freewheel, put a single freewheel on it and respace the wheel so your chain lines up properly. the bulletproof cranks will help with this as they can choose the inner or the outer position for the chainring.

    this should cost you:
    freewheel: $25 (ACS)
    chainring: $15 (sinz probably)
    cranks: $35 (bulletproof)
    chainring bolts: $10
    Labor: $40 (estimate)
    total: $125

    that's about as cheap as you can get at your local LBS, and wind up with something i'd actually condone riding. if your area has a bicycle co-op you could cut this price in half or more, possibly make some friends and learn some things about your bike.

    good luck!

  11. #11
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    ok im either going with profile or what killsurfcity has, and i plan on getting disc brakes for the rear tire anyways. Thats why it doesnt matter if my v brakes dont line up any more

  12. #12
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    Quote Originally Posted by Dank Methods
    ok im either going with profile or what killsurfcity has, and i plan on getting disc brakes for the rear tire anyways. Thats why it doesnt matter if my v brakes dont line up any more
    Don't want to rain on your parade here, but if you want a rear disc brake you're going to need a new rear hub or a new wheel, which don't come cheap, unless you have disc mounts on your current hub (which i doubt) and all that is for nothing if you don't have disc mounts on your frame (which i also doubt). I think the best way to go from here is to try and post some pictures of this beast so that we can give better advice.

    Good luck.

  13. #13
    the test dummy
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    Quote Originally Posted by Effrum
    Don't want to rain on your parade here, but if you want a rear disc brake you're going to need a new rear hub or a new wheel, which don't come cheap, unless you have disc mounts on your current hub (which i doubt) and all that is for nothing if you don't have disc mounts on your frame (which i also doubt). I think the best way to go from here is to try and post some pictures of this beast so that we can give better advice.

    Good luck.
    agreed pics would help I'm kinda confused
    Quote Originally Posted by craftworks750
    Riding a mtb is like a reset button, 10 mins in and there is nothing else in the world that matters.
    my bikes
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    Ben

  14. #14
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    Quote Originally Posted by Effrum
    Don't want to rain on your parade here, but if you want a rear disc brake you're going to need a new rear hub or a new wheel, which don't come cheap, unless you have disc mounts on your current hub (which i doubt) and all that is for nothing if you don't have disc mounts on your frame (which i also doubt). I think the best way to go from here is to try and post some pictures of this beast so that we can give better advice.

    Good luck.
    nah its all good, your right to assume i dont have disc mounts, but its not a problem. awhile ago when i called the LBS i asked if they sell disc mounts so i can weld them on to my bike. They said yes for around 15$-20$. I havent got them yet cause I plan on getting a new back tire (the 24") anyways and im going to buy it all together. I also plan on getting a Gyro to work with my MTB and the disc brakes, and if its possible which i doubt is get rear mags (old school plastic looking large spokes) to go with the back tire disc brakes. So if you haven't figured it out yet Im trying to make a bit larger sized bmx bike but with DS.

    Thanks so far to all that are helping me "Pimp My Ride".

  15. #15
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    lol awesome is the only way this could end.

  16. #16
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    There seems to be one thing that has been overlooked. In all the discussion about brakes, BB height, etc... the big issue here is that the smaller wheel in the same fork will result in much less trail. The bike will become very twitchy, which is okay if that is what the OP wants.

  17. #17
    AZ
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    He will be lucky if all he has to worry about is twitchyness .

  18. #18
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    i wonder if OP is a fan?

  19. #19
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    Quote Originally Posted by killsurfcity


    i wonder if OP is a fan?
    i dont think he is a troll, just younger and/or a fan of the green leaves

  20. #20
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    i could see how that's possible, but i'm still skeptical.

  21. #21
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    Why is all I want to know.......... Buy a 24'' cruiser for cheaper than all this BS.... just my opinion.....

  22. #22
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    yeah, imo, this conversion is going to end up being way more costly than the obvious alternative, and produce a machine that is awkward and therefore not fun to ride.

    while bucking the perceived rules to make something unique may seem cool, when it comes to mechanical objects often the result is something that just doesn't work.

  23. #23
    Gigantic Hawk
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    If you are going to go through the trouble of welding on disc mounts, it'd be easier to weld on new v-brake mounts. This way you can get around the impossiblilty of creating a rear 135mm mag with iso mounts.

    Put your frame in a vise to compress the rear dropouts together, shove in an old 24" wheel with a coaster brake, and have at it.

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