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  1. #1
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    1984 Trek 500 27" --> 700C conversion ... can i tour it?

    I'm considering buying this bike: http://seattle.craigslist.org/sno/bik/983569769.html to do extensive touring and possibly commuting. It's built for 27" wheels and I want to convert it to a 700c set. Will the altered geometry of putting smaller wheels on (and possibly swapping the fork, if necessary) cause extra wear and tear on the frame? Any suggestions are helpful.
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  2. #2
    Older than dirt CCrew's Avatar
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    27" and 700C are so close it's almost inconsequential. The several I've done we had to change nothing except the wheels, and adjust the brake pad positioning.

    622mm dia on the 700c versus 630mm on the 27". Half that on the diameter which means the pads need to move 4mm.

    -Roger

  3. #3
    Senior Member mijome07's Avatar
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    I'd replace those chainring bolts and clean the chainrings.

  4. #4
    Acetone Man
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    the geometry difference is small enough to be utterly insignificant. A new fork will not be necessary. 700c conversion means the brake pads need to move down 4mm. Photo shows the (front at least) pad mounted in the middle of the brake arm; you should therefore have enough adjustment room to run 700c rims with the same brakes.

    Considerations for touring:

    The brakes it has are inadequate for carrying loads. A pair of modern long reach dual pivot calipers will do you fine for power and reach, but mounting them can be tricky, since modern brakes use recessed nuts, while older bikes like that trek use exposed nuts. technical detail on making modern calipers work with old frames here at
    http://www.bikeforums.net/archive/in.../t-232521.html

    The frame is decent, but not made for loaded touring. It will be uncomfortably floppy with more than 30ish pounds of gear, fine for overnighters and weight weenies, but could be lacking depending on what your vision of extensive touring is. The affordable way to do heavier touring is with a late 80s/early 90s rigid MTB, like my 1994 Trek 930

  5. #5
    Senior Member Nigeyy's Avatar
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    On the flip side, I found the changes are noticeable (and not inconsequential!!) on the bikes I've had. It really depends on your bike. Looking at the photo, it looks suspiciously like the pads are more at the bottom end of their adjustment.

    But why change? Though 27" tyres are harder to find and you do have less of a choice, you can still find them. Unless there's a compelling reason to, it might be easier to keep them, though I won't deny you'll be better off with 700C for the long term and for choice (and obviously if the current rims are shot -I notice they are 36h which is good -this is a good time to consider the conversion assuming you can do one with no problems). Geometry wise, I haven't done this change, but would assume the differences would be marginal; it would not be a concern to me.

    Concerning the bike, I'm sure it would be fine for lightweight touring, though there might be some heel strike as it's not a pure touring bike, and the gears looks like they will be too high, so you *might* find yourself spending more money than you think you might (unless you are really going lightweight on the touring). And unless you have a real want to use 700c, as the previous poster mentioned, you might be better off waiting for a cheap old style mtb that you can convert with slicks (my neighbour has a Trek 930 he uses to tour on, and I can attest it's a very nice frame for that).

    edit: I notice you are referring to an ad in Seattle. If you use caliper brakes, then without a lot of jiggery pokery and cutting into the fenders (don't ask) you will not have fenders on the bike. In rainy conditions touring, fenders are very, very nice to have.

    Quote Originally Posted by CCrew View Post
    27" and 700C are so close it's almost inconsequential. The several I've done we had to change nothing except the wheels, and adjust the brake pad positioning.

    622mm dia on the 700c versus 630mm on the 27". Half that on the diameter which means the pads need to move 4mm.

    -Roger
    Last edited by Nigeyy; 01-08-09 at 05:52 AM.

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