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  1. #1
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    Help - 1997 Bontrager Race Lite crankset

    I'm in process of rebuilding by 97 Bontrager. It's taken some abuse over the years but looks like it's going to clean up very nice. I've post a few photos over on the Bontrager thread:

    Official Bontrager Thread

    It's all original right now and I'd prefer to keep it that way if possible.

    The problem is that the right crankarm has a major crack in it which I knew about before I took it apart. And tonight looking closely at the left crankarm it too has a pretty major crack in it. The cranks are Shimano XT M739s. I have hoped to find some original replacements as they are out there though the good ones seem priced ridiculously high while the beaters are less but still on the high side. And I'm questioning the wisdom of replacing them with the same items which have proved to be susceptible to cracks. Anyway, I would like ideas as I'm willing to explore other options. The bottom bracket is a square taper, the original chainrings/chain are IG and it is an 8 sp. Doing a quick search on ebay I saw some M737 cranks which are one piece arms and perhaps some XTR M950s if they come in silver. The originals were silver arms with silver chaingrings.

    Any other ideas? Thanks for the help.

  2. #2
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    Just saw your frame, very nice! Too bad I'm WAY over the weight limit on those....

  3. #3
    the new Gilbert Grape
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    My Bontrager came with the m739 cranks as well. I was never a fan of it. It worked well enough, but only came with a 42T big ring, and the big ring is permanently attached to the spider - making for expensive replacements. I'd opt for a different crankset.

    Bontragers were sold as framesets, so you can pretty much built it as you'd like and it's "correct" (assuming that matters). My current Bontrager is built with a mish-mash of parts; I still ride the bike a lot, so I use what I like regardless of component age.
    Each bicycle owned exponentially increases the probability that none is working correctly.

  4. #4
    マスターの自転車整備士
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    PM sent.

  5. #5
    Humanoid Lobster
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    Have a look through the Bontrager thread - you can see just about every crankset you can think of on the various Bonty's there.

    Laffeaux pointed out the shortcomings of the M739's. I'd say find something else that you like and go for them instead. There's a ton of square taper stuff on ebay that you can probably even reuse your BB with. The nice thing about riding vintage is that you can benefit from hindsight and run what works. (Or alternately, the CNC'ed peacock anodized cranks that you couldn't afford BITD are now within reach.)
    Don't call it a gooseneck.

  6. #6
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    Always thought these looked great on steel framed bikes!

    Help - 1997 Bontrager Race Lite crankset-syncros-bonty.jpg

    Also... I've had good luck finding used complete bikes with the parts I'm seeking, often for the same price or less than the part itself on Flea bay.

  7. #7
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    Thanks to all those who have responded - and quickly at that. And all good ideas and food for thought. My frame did come fully assembled at the end of the Bontrager run with mostly full XT but know that they were mostly frames before that. I think I'd like to keep it at the XT level but all the newer stuff is HG, or Isis or hollow spindle stuff. I did like the look of the M737 though. The BB does seem to be working ok so will probably stay with square taper. Plus, I can always put something on and if I don't like it replace it later.

    The idea of buying a whole bike is a good one and thank you cyclejce who sent me a CL link to one (Trek) in Denver (I'm in San Diego). The problem with that is then I end up with another whole bike and for some reason I don't like to part them out - so would probably have another project on my hands. And laffeaux's comments were good - I hadn't realized the big ring is a 42 - not that I need much more. I've not looked closely at the Syncros cranks before but have always liked the Cook Bros which are similar. I was even thinking of a Sugino in a simple sort of way. Anyway, a member here sent me a PM and he has a set of M739s that I'm going to take a look at. Will keep you updated. Thanks again to all.

  8. #8
    gobsmacked Moderator
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    Maybe keep the outings and pms of members that offer to sell stuff to you under your hat as they are not in line with forum rules or how this forum works. Check out the stickies.

    I would say good luck but you don't need it as square taper cranks can be had for cheap.

  9. #9
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    Will do - thanks

  10. #10
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    Quote Originally Posted by laffeaux View Post
    My Bontrager came with the m739 cranks as well. I was never a fan of it. It worked well enough, but only came with a 42T big ring, and the big ring is permanently attached to the spider - making for expensive replacements. I'd opt for a different crankset.

    Bontragers were sold as framesets, so you can pretty much built it as you'd like and it's "correct" (assuming that matters). My current Bontrager is built with a mish-mash of parts; I still ride the bike a lot, so I use what I like regardless of component age.
    Hens tooth found at LBS today...

    Help - 1997 Bontrager Race Lite crankset-xt-42t.jpg

  11. #11
    gobsmacked Moderator
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    You tease! Poor Dr Spoke.

  12. #12
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    That is a tease - however it's the arms I'm looking for as both have cracked. I'm sure the chainrings are worn too but they aren't the main issue.

    Would a 9 speed crankset work? Would the chain be too wide - either externally or internally? Would the rings be too close together? Would the 8-sp front indexing be off?

    Something like this:
    Shimano XT M760 9 Speed Chainset | Chainsets - MTB | Merlin Cycles

    I guess I was harder on this bike than I thought. Or else neglected the maintenance. The rear wheel bearing race in the freehub has some chunks out of it. They're not where the bearings run so I hope I can reuse it. And the lower bearing in the headet, supposedly sealed, came apart in pieces when I took the fork off - bearing everywhere. I thought this would be easier than the old Schwinns I've been doing lately. But those old bikes are bulletproof. Rusty - but bulletproof.

    Thanks again to all who have contributed ideas so far.

  13. #13
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    Found a set - on eBay as expected - and I won for less than what I bid on and lost for 2 different sets last week. And I don't think were as nice as these either.

    Shimano Deore XT Crankset FC M739 175mm Very Good Condition | eBay

    Anyway, I think I'm going to be happy with these - let the rebuild commence.

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