Request for help with lower gearing for my 7-speed

Discussion in 'Cycling Equipment' started by CandyEpic, May 21, 2003.

  1. CandyEpic

    CandyEpic New Member

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    I'm preparing for a cycling tour this summer which will involve a number of difficult climbs. I've recently started training for this event doing a lot of climbs where I live. Generally, it's flat. I learned quickly that I'll have to do something with the cassette to get lower gearing (39T up front, 24T in back). I would like to get a cassette with at least a 28T in the back, preferably a 30T.

    Not knowing much about history of freehubs and cassettes, I have been told by a local bike shop that my bike has an old Shimano freehub/cassette style that was only made for 1 or 2 years. Here's my setup:

    7-speed Shimano 600 drivertrain
    Shimano Dura-Ace rear (free)hub
    The smallest cog on the cassette threads onto the outer portion of the freehub.

    There is the problem. The freehub I've got will not accept 7-speed Shimano cassettes sold by the likes of Nashbar and Performance. Aside from looking on eBay for parts, what can I do?

    I am hoping someone with knowledge on this subject can help me out with following questions:

    - which years were this style of hubs/cassettes sold?

    - Are the spacers and cogs for Shimano 7-speed cassettes and 8-speed cassettes of the same era interchangeable?

    - Can I use the larger cogs from an 8-speed XT cassette along with two of the smallest cogs on my freehub as this article suggests?
    (see link below)

    - Does slight twist on each tooth of the cassette serve a purpose other than "filling" the slot in each chain link? I ask because it appears that (looking from the top of the bike down) the XT teeth are straight, while the teeth on my 7-speed cassette are slightly twisted.

    I really appreciate your thoughtful replies. My screaming knees will thank you also!

    www.insidetri.com/train/bike/articles/1328.0.html
     
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  2. DiabloScott

    DiabloScott New Member

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    If you've got 7-speed you probably have downtube shift levers that you can put in friction mode. If that's the case you can put the XT cassette on your Dura Ace hub (maybe even a 9-speed if you have the right spacing and hub and you get a new chain) and just use friction shifting because the cog spacing won't matter.

    7-speeds were the standard for quite a few years, but it was during the time of the switchover from freewheels to cassette hubs too so there are a lot of variations out there.
     
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