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Conference noted::bicycle

Title: Bicycling
Notice:Bicycling for Fun
Moderator:JAMIN::WASSER
Created:Mon Apr 14 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3214
Total number of notes:31946

1875.0. "MTBs: Chainstay Length -and- Frame Material" by OFFHK::MURRAY (Tom, Telecom AD and Architecture, MKO2-1/D9) Mon Mar 11 1991 13:19

        I'm not yet indoctrinated to MTBs but have been shopping and I
        am getting inconclusive advice on...

        - Chain stay length - does 16.75" vs. 16.9" make any difference? 
        Climbing?  Descending?

        - Frame material - Aluminum vs. steel alloy.  I don't care on a
        fat tire bike that Al rides better, but does it dissipate less
        energy due to flex?  Does it save enough weight to make a
        difference? 

        It might help to note that I am comparing Diamond Back Axis
        (16.75) vs. Trek 970 (16.9); and then Trek 970 (steel alloy) vs.
        Trek 8000 (Al).  These are similar bikes except for the
        differences I note.  

        Are these too costly a range to start out ($700-$825*)?  Not
        costly enough?  I would prefer to buy something that I'll be
        happy with and won't have to upgrade later.  I expect to get 
        enthusastic but not race.

        * S&W Sports in Concord NH discounts Treks; Ultrasports in
        Manchester seems to discount Diamond Back.

        Thanks, Tom

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1875.1WUMBCK::FOXWed Mar 13 1991 13:0734
>        - Chain stay length - does 16.75" vs. 16.9" make any difference? 
>        Climbing?  Descending?
    That amount probably won't make that much difference to the casual
    rider. Generally a shorter chainstay gives you better climbing ability
    due to having more weight proportioned on the rear end. It also gives
    a harsher ride, since you're closer to sitting where all the action is.
    Descending, I don't believe chainstay length plays  the same part. If
    your flying down a rough decline, you want stability. That is achieved
    via longer wheelbases, and more relaxed frame angles. The chainstay
    will effect wheelbase, with everything else being equal.
    It all comes down to compromises. You can't have hands-off stability,
    and lightening quick reflexes, or excellent saddle comfort, with
    supurb climbing abilities (then again, I haven't ridden a suspended
    MTB bike).

>        - Frame material - Aluminum vs. steel alloy.  I don't care on a
>        fat tire bike that Al rides better, but does it dissipate less
>        energy due to flex?  Does it save enough weight to make a
>        difference? 
    Al can be stiffer or more flexible than steel depending on the grade
    and thickness of the given materials being compared. Generally, Al
    is stiffer and only marginally lighter than quality steel.

>        Are these too costly a range to start out ($700-$825*)?  Not
>        costly enough?  I would prefer to buy something that I'll be
>        happy with and won't have to upgrade later.  I expect to get 
>        enthusastic but not race.
    
    Hard to say. The best bet is to try each one for as long a time as
    possible. Try to put them through what you expect to use your bike
    for. Choose the one you like best!
    
    John
1875.2Also try the original commercial mtb: the StumpjumperCIMNET::MJOHNSONMatt JohnsonThu Mar 14 1991 11:006
    The only way to know is to ride.  Of the bikes I tried at that price,
    the low-end Specialized Stumpjumper (Shimano DX, I think) was the 
    nicest off-road, especially on tough descents.  
    
    
    MATT
1875.3Start lower - find your preferencesCARROL::SOLONTue Mar 19 1991 16:2313
       One thing mentioned to me at shops is that a bent STEEL frame can
    usually be repaired much more easily than an aluminum frame.  Having
    just bought my first MTB myself, I found that I was able to get a good
    spec bike (Tange frame, Deore LX, Araya rims) relatively cheap - around
    $400.  My plan is to ride it long enough to find out 1)do I enjoy this
    type of riding (so far so good), 2)what do I like and what do I dislike
    as far as components, geometry, features, and 3)I will have a reference
    to really judge other bikes if I want to change or upgrade.
        I suspect it's easier to unload a mid-range bike without loosing
    too much than a high end one, if you decide you want something
    different.  Hope this helps.
    
    Tom