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  1. #1
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    Newbie question--changing cranks on a Trek 520

    My first postóhi to all! I have a 2005 Trek 520, havenít done any serious touring yet but want to eventually. I feel the stock gearing might be too high for me with a loaded rig. I was looking at the Shimano LX FC-M581 Trekking crankset on the Nashbar web site. Would this work on the Trek 520? I was also looking at the Sugino XD2 crankset on the Rivendell web site. Has anyone out there used either of these cranksets on the Trek 520? I noticed the Shimano crankset comes with a bottom bracket. Would I have to buy a different bottom bracket with the Sugino?

    I can use (I hope) the Shimano crank from the 520 on road bike I want to rebuild so it wouldnít be a total loss on that end.

    I would ask the LBS, but they think Iím crazy for wanting lower gears. Iíve been using the bike as is, and itís fine, but when I get on serious hills, I feel like I could use some lower gears.

    Thanks in advance for any replies.

  2. #2
    Senior Member Ziemas's Avatar
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    Quote Originally Posted by fromabuick6
    My first postóhi to all! I have a 2005 Trek 520, havenít done any serious touring yet but want to eventually. I feel the stock gearing might be too high for me with a loaded rig. I was looking at the Shimano LX FC-M581 Trekking crankset on the Nashbar web site. Would this work on the Trek 520? I was also looking at the Sugino XD2 crankset on the Rivendell web site. Has anyone out there used either of these cranksets on the Trek 520? I noticed the Shimano crankset comes with a bottom bracket. Would I have to buy a different bottom bracket with the Sugino?

    I can use (I hope) the Shimano crank from the 520 on road bike I want to rebuild so it wouldnít be a total loss on that end.

    I would ask the LBS, but they think Iím crazy for wanting lower gears. Iíve been using the bike as is, and itís fine, but when I get on serious hills, I feel like I could use some lower gears.

    Thanks in advance for any replies.
    You can always just change the rings on the crankset that you have on the 520. It would be much cheaper.

  3. #3
    Caffeinated. Camel's Avatar
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    Quote Originally Posted by fromabuick6
    ...I would ask the LBS, but they think Iím crazy for wanting lower gears. Iíve been using the bike as is, and itís fine, but when I get on serious hills, I feel like I could use some lower gears...
    Most bike shops may not understand what you want the lowered gearing for. At the same time, many may not have experience setting up rigs for loaded touring. Take a moment to explain what types of loads you will be carrying, for how long, and over what type of terraine-an experienced mechanic should "get it".

    That said, as Ziemas wrote, you should be able to change the rings. I recently set up my Brevet bike with an Ultegra triple (52/42/30). I swapped the 30 "granny" gear for a 26, and left the other rings. I also switched from front STI shifting to downtube friction-it shifts just dandy, even with the original "double" derraileur. Note however, that I don't carry hardly any load > ~8lbs+water on this rig-just an example of what can be done.

    My touring rig on the other hand, has all 3 rings swapped out: Shimano Ultegra, 24(generic)/38/48 TA rings. Swapping rings can get allmost as pricey as a new crankset, but the previous owner had it set up allready for me (except I did lower the granny). I've this matched with a Shimano XT freewheel (11/12/14/16/18/21/24/28/32), but will CERTAINLY swap the cassette out for one of Sheldon's for my next big tour. I rarely needed the 11/12+48, but could certainley have used a 34 rear on several occasions. The tighter spacing would have been handy as well.

    Along with lowering the front gearing, consider a "larger" rear cassette. Say something with a 30, 32, or 34 large sprocket (provided you have a long cage rear deraileur). If you can afford one, look into Sheldon Browns custom touring cassettes. These drop the high end sprockets (11/12 perhaps 13), giving closer spacing, and better low gearing. Link to Harris cyclery custom cassettes. Note that I "think" you can make your own customized cassettes, by mixing an LX with an Ultegra-if you happen to have new ones of both, or can get ones cheap. I think it's just cheaper&easier to buy one allready set up from Harris.

    -Anyways...

    a) That LX crankset off nashbar seems nice.
    b) Gearing can be trickey to get right for the individual rider/load.

    Take some time and play with an online gear calculator (such as Sheldon Brown's found here)-using a high cadence/spin (80-90). I've spent the better portion of a day on a few occasions spinning happily up climbs (with breaks of course) at close to or bellow walking speeds with a load, and happy knees. A larger rear sprocket (the 34) would be handy (for me) on the steeper sections of climbs-usually at the corners where grades are highest.

  4. #4
    Banned Bikepacker67's Avatar
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    I just use a standard MTB 22-34-44 crankset (mine's Truvativ, but Shimano is fine) with a Shimano 11/13/15/17/20/23/26/30/34 cassette.

    That gives me a low of around 17 gear inches. Which - when fully loaded for bear - comes in handy for things like this:


  5. #5
    aspiring wannabe hoogie's Avatar
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    I had the same issues with my Trek 520, and i changed the stock 105 cranks for LX cranks [44/32/22] ... it works good, but i did have to change the bb as well ... i also installed flat bars and LX rapidfire plus brake/shifter combo [LX mtb ones], and basically haven't looked back ...

    from memory, but don't qoute me on this ... i think that the splined bb on road based components is different to the mtb based components, you migt need to get your lbs to confirm this ...

    my trek 520
    thought for today: "Does my ass look fast on this bike?"

  6. #6
    aspiring wannabe hoogie's Avatar
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    I had the same issues with my Trek 520, and i changed the stock 105 cranks for LX cranks [44/32/22] ... it works good, but i did have to change the bb as well ... i also installed flat bars and LX rapidfire plus brake/shifter combo [LX mtb ones], and basically haven't looked back ...

    from memory, but don't qoute me on this ... i think that the splined bb on road based components is different to the mtb based components, you migt need to get your lbs to confirm this ...

    my trek 520
    thought for today: "Does my ass look fast on this bike?"

  7. #7
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    Thanks for the responses. I have considered switching just the chainrings, but they seem to be almost as expensive as a new crankset. Plus Iím hoping to use the Trek crank on another road bike I have.

    I just wanted to make sure before I order another crankset, itíll work on the Trek. Iíve done some repairs etc on bikes, but havenít swapped cranks yet.

  8. #8
    Banned Bikepacker67's Avatar
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    Oooooohhh.... I Like that bike, Hoogie!


    Quote Originally Posted by hoogie
    I had the same issues with my Trek 520, and i changed the stock 105 cranks for LX cranks [44/32/22] ... it works good, but i did have to change the bb as well ... i also installed flat bars and LX rapidfire plus brake/shifter combo [LX mtb ones], and basically haven't looked back ...

    from memory, but don't qoute me on this ... i think that the splined bb on road based components is different to the mtb based components, you migt need to get your lbs to confirm this ...

    my trek 520

  9. #9
    aspiring wannabe hoogie's Avatar
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    gosh ...

    thanks for your kind comment ... still like my Nomad though ...
    thought for today: "Does my ass look fast on this bike?"

  10. #10
    Gone ridin' Joeagain's Avatar
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    I did the same as hoogie, but had to change the FD as well as what he did. (Same model bike, same crank/ ring, etc.). Well, my LBS did it. Think I'll go with a slightly higher geared middle ring when replacement time comes around, but I'm pretty happy with it.

    Joe

  11. #11
    Radio Bemba 00.0 EnLaCalle's Avatar
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    Don't want to sound like a snot, but have you tried loading up your bike and riding up some hills before you go ahead and spend money on a new crankset? I have a Trek 520 that I toured South America on, like silly-loaded. I've yet to encounter again hills like the ones I rode up in the Andes and I did fine with the stock gearing. That being said, there were times where I wouldn't have minded having a couple more lower gears to shift onto, but it definitely wasn't necessary. I'm not trying to dissuade you from doing what you think you need to do. I'm just wondering if you've tested what you've got yet.

  12. #12
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    Quote Originally Posted by EnLaCalle
    Don't want to sound like a snot, but have you tried loading up your bike and riding up some hills before you go ahead and spend money on a new crankset? I have a Trek 520 that I toured South America on, like silly-loaded. I've yet to encounter again hills like the ones I rode up in the Andes and I did fine with the stock gearing. That being said, there were times where I wouldn't have minded having a couple more lower gears to shift onto, but it definitely wasn't necessary. I'm not trying to dissuade you from doing what you think you need to do. I'm just wondering if you've tested what you've got yet.
    I understand that. Iíve been out biking around Seattle here where we have plenty of steep hills. If I were not thinking of touring, Iíd leave the gearing the way it isóI can climb pretty much any hill with the 30/34 combination. But I do find myself wanting a lower gear on some of the steeper hills. I went back to the LBS here and talked to a different mechanic who was more amiable to swapping out chainrings. He said it would be possible to replace the 30 with a 26 and it would probably work OK. Iím leaning towards doing that instead of changing the whole crankset. I actually use the higher gears on some of the converted rail trails out here when thereís nothing in my way and I can fly.

  13. #13
    Sabbanides dvsabban's Avatar
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    I'm new to this whole gear changing thing too. Is it actually possible to change just the 30 front chainring on my Trek 520 (to something smaller) and keep everything else the same?
    Camel (#3 above) seems to imply that.

    Please clarify if you would. Thanks very much!

    David, now "Cranky in Seattle"

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    Banned Bikepacker67's Avatar
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    Quote Originally Posted by fromabuick6
    I actually use the higher gears on some of the converted rail trails out here when thereís nothing in my way and I can fly.
    Let's say your top-end is 53-11 combination.... if you keep a 90 rpm cadence you'd be flying at about 35 mph.

    With a 44-34-22 crankset, (and the same 11 tooth cassette cog) I can hover around 30mph at 90 rpm.

    I'd rather have the low-end gearing at the end of a long day of touring, when faced with longclimb #17.

  15. #15
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    Quote Originally Posted by dvsabban
    I'm new to this whole gear changing thing too. Is it actually possible to change just the 30 front chainring on my Trek 520 (to something smaller) and keep everything else the same?
    Camel (#3 above) seems to imply that.

    Please clarify if you would. Thanks very much!

    David, now "Cranky in Seattle"
    The mechanic I talked to seemed to think it would work OK. He said if it were too big of a jump, the middle chainring might have to be changed to a 40 or 38. Has anyone out there tried this on a Trek 520?

  16. #16
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    No, but my tandem had 48-38-24. It works in our kind of terrain which is mostly flat or gently rolling, but with a few steep hills here and there. No shifting issues, but I sometimes wished for a smoother transition between gears available on the 24 and the 38.
    The tandem now runs as a quad with 48-38-28-18... mostly because I wanted even lower gears.
    Michel Gagnon
    Montrťal (Quťbec, Canada)

  17. #17
    Caffeinated. Camel's Avatar
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    Quote Originally Posted by dvsabban
    I'm new to this whole gear changing thing too. Is it actually possible to change just the 30 front chainring on my Trek 520 (to something smaller) and keep everything else the same?
    Camel (#3 above) seems to imply that.

    Please clarify if you would. Thanks very much!

    David, now "Cranky in Seattle"
    To clarify, I made this change on a bike I use for randonneuring, looong timed rides (brevets 200-1200Km) for a personal best. These rides usualy have a heck of a lot of climbing involved as well.

    I wrote about changing the 30 granny to 26, while keeping the 52/42 only as an example of what can be done. I do think that the granny could go as low as 24. Shifting is pretty descent-but again I switched from front STI to front friction.

    Note:

    -I had to swap out my rear deraileur (changed from double to triple).

    -I keapt the original front deraileur, so cross chaining when in the granny is not possible. Only the 4 low end rear sprockets are actually useable before deraileur/chain scrape is an issue (on my tourer I can cross chain should I want to).

    I would not suggest doing this for a loaded tourer, unless one really has to (and knows when they have to shift). For loaded touring there is no need for such a high end (52+) IMO.

    Perhaps more suitable for a credit card tourer? Sorry for the confusion...more of a "look what I did" kind of post I guess vs relevent to the OP's original inquiry. Oops.

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    I just upgraded my new 2005 Trek to an LX 44-32-22. you can either get the cranks that fit an Octalink BB. (you'll need to change BB since the LX need the the longer splined Octalink BB) The cost of the LX Octalink cranks can be found for aroung $80-90. If you go with the new intergrated version it will cost aroung $160. I debated and wound up going with the older version since part availability would be better on a tour. Also if you ebay the 105 cranks and BB that you remove then your net upgrade cost wouldn't be that much.

    The 105 front derailleur works fine with the 44-32-22. I took the trek 520 on a club ride I took it up to 26mph no problem, the weight vs my litespeed Vortex eventually got to me though.

  19. #19
    Banned Bikepacker67's Avatar
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    C'mon now...
    Everything you said up to the last comment was spot on.

    Are you trying to tell me that you were affected by the diff in WEIGHT between your old crankset and the new one?

    Why does this remind me of the Princess and the Pea?


    Quote Originally Posted by like2bike
    The 105 front derailleur works fine with the 44-32-22. I took the trek 520 on a club ride I took it up to 26mph no problem, the weight vs my litespeed Vortex eventually got to me though.

  20. #20
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    That wasn't my point. I never even considered the weight difference between the 105 cranks that came off the Trek 520 vs the LX cranks that went on. It didn't matter to me. I was more intent on the resulting gearing.

    It was really a irrelevent contribution. I was just making a point that with the 44T big gear up front the bike has more top end gear than you need for touring. It's enough to do club rides if you want. I just don't intend to take the Trek 520 out for regular club rides since it's heavier than my Vortex.

    As a side note: It was fun pulling up to the regularly scheduled Saturday club ride on a touring bike with grifters, fenders, rack, and rack trunk around all those pretty, sleek, expensive road bikes and keeping up for most of the ride. Really fun to ring the bike bell that I mounted every now and then. I also took the Trek 520 out on a foul weather club ride and loved the fenders and 32cc tires. If it's wet I'll leave the fancy road bike at home and take the Trek from here on out.

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