Reduce, Reuse, Recycle - Feasible to use FSA SL-K road crankset on 29er SS?- Mtbr.com
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  1. #1
    Bad Case of the Mondays
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    Reduce, Reuse, Recycle - Feasible to use FSA SL-K road crankset on 29er SS?

    I went to compact gearing on my road bike to get me up the long, grinding steep climbs here on the Front Range of CO. In doing so I have a very nice carbon FSA SL-K crankset that is sitting around gathering dust.

    I'm building up another 29er SS and I've got the crazy notion to try to reuse the FSA crankset. Both the road bike and the new frame use 68mm bb shells, so I think I'm OK. I can run a 38t up front with a 23t cog and get the same ratio as my 32:20 on my Niner SIR9. I've found non-ramped, no pin chainrings for its pattern as well.

    And yes I realize that the road crankset won't be as resilient to rocks and such, but this is going to be an "in-law" bike, meaning its going to reside in Arkansas at my in-laws place giving me a bike to ride when we are out visiting as they are close to lots of great trails and paths. I'm expecting most of its life to be spent riding roads, gravel paths and buff singletrack.

    My only concern is will the road crankset have such a narrow Q factor that the crankset will hit the chainstay. Anyone else try something like this? What else I am not considering?

  2. #2
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    You might have to mount the 38 in the outer position for it to clear the chainstays too.

  3. #3
    is buachail foighneach me
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    if you can get the chainline right, running a cassette hub, it should work fine. like you said, ground clearance will be an issue. is it 170? if you could find a way to get a metal plate over the end of the crank where it would contact rocks it'll save alot of stress.

  4. #4
    Occasionally engagedů
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    Quote Originally Posted by Jdub
    My only concern is will the road crankset have such a narrow Q factor that the crankset will hit the chainstay. Anyone else try something like this? What else I am not considering?
    That is a concern and many 29er frames won't have the clearance -- pretty much just have to measure it or install it to know. You will definitely need to mount the chainring on the outside of the crank, but that makes for a better chainline in most cases anyway. Interestingly, the outside position of a road double crank lines up with the White Industries ENO hub (~47 mm chainline) if you're using a single speed freewheel. The other place you might have clearance issues even if you can get the crankarm past the chainstay is having the spider/chainring bolts hit the chainstay near the bottom bracket --- that was an issue for one bike I tried a road double crankset on. I have had a new 29er singlespeed for less than a month (not much riding with all the snow we've been getting) that was built specifically to clear the Ritchey WCS Road Compact double crank -- I actually gave the frame builder the crank and bottom bracket so he could make sure everything fit (crank clearance and tire clearance). I absolutely love low Q-factor set-ups, hence my willingness to pay for a custom frame to get it to work well...
    "The plural of anecdote is not data." -- Attributed to various people in a variety of forms, but always worth remembering...

  5. #5
    CB2
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    I tried using a FSA Energy compact crank, and there was only 1 mm clearance to the chainstays.

  6. #6
    mvi
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    In my experience you need a road TRIPLE with the ring outside to get barely enough clearing for the spider.
    With square taper more options probably.
    130 mm spiders are much bigger!

  7. #7
    Bad Case of the Mondays
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    Quote Originally Posted by PeT
    pretty much just have to measure it or install it to know.
    I think you are right, there are too many variables (frame, bb, crank, etc) to know for sure. I mainly wanted to think out loud and see if anyone else has had success doing something like this.

    I'll probably just end up selling the FSA SL-K crank and then buying a mountain crankset with the proceeds. Just had this vision of how nice the carbon weave would look next to that metallic green..... Oh there I go again...

  8. #8
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    Quote Originally Posted by mvi
    130 mm spiders are much bigger!
    True story.
    Attached Images Attached Images
    altBike.com: One for the ride.

  9. #9
    The Dog.
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    Quote Originally Posted by Jdub
    I went to compact gearing on my road bike to get me up the long, grinding steep climbs here on the Front Range of CO. In doing so I have a very nice carbon FSA SL-K crankset that is sitting around gathering dust.
    Oh come on! You are a singlespeeder! What did people do before compacts? They either sucked it up and got strong on a 39-53, or they sucked it up and wore the shame of a triple. I've never met a climb in the front range that couldn't be tackled with a standard 39-53 and 12-15.

    Here's what you do:
    -Ride your other singlespeed more to get stronger.
    -Remove the compact and put the FSA SL-K back on
    -Sell the compact and buy an Eno or some Middleburns.

  10. #10
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    Quote Originally Posted by Dogdude222
    Oh come on! You are a singlespeeder! What did people do before compacts? They either sucked it up and got strong on a 39-53, or they sucked it up and wore the shame of a triple. I've never met a climb in the front range that couldn't be tackled with a standard 39-53 and 12-15.

    Here's what you do:
    -Ride your other singlespeed more to get stronger.
    -Remove the compact and put the FSA SL-K back on
    -Sell the compact and buy an Eno or some Middleburns.
    I've been called out, and I can't really disagree with you...

    I am a SSer, but a new convert. I just got my Niner last winter, so I'm still strength building. I can climb the steep stuff fine, but the 6% grades for 10 miles just blow me up. I'm a big guy (190lbs), so gravity isn't on my side but I see your point and will give that some consideration.

  11. #11
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    I've done this on two bikes, both were steel framed. Any kind of flared stays at all and you will hit the crank arms oin the stays........

  12. #12
    The Dog.
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    Quote Originally Posted by Jdub
    I've been called out, and I can't really disagree with you...

    I am a SSer, but a new convert. I just got my Niner last winter, so I'm still strength building. I can climb the steep stuff fine, but the 6% grades for 10 miles just blow me up. I'm a big guy (190lbs), so gravity isn't on my side but I see your point and will give that some consideration.
    I can't believe it! I was abrasive, and you agreed with me!

    If you want your compact, then have your compact my good man. You deserve it just for having extraordinary forum manners.

  13. #13
    HIKE!
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    I run a Race Face Cadent road crank (110mm bcd) with a 36t ring. Clears the stays fine on a Kona A, and a Santa Cruz Chameleon. Chainring in the outer position. Solid, up to the task, correct chainline and narrow-ish tread (some call this Q-Factor). It'd clear a 38t, or even 42t.

  14. #14
    Bad Case of the Mondays
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    And the answer is.......

    No.

    The 39 chainring clears fine, but the drive side crank arm just barely scrapes the chainstay. Could probably come up with some sort of spacer or something like that, but at this point it makes more sense to let the nice road crankset go to a loving home and get a real mountain crankset.

    But damn the carbon would have looked good up against that sparkling green metallic paint.

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