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  1. #1
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    Help with Marathon frame size and fit/standover height

    Hi to all the GT fans. Having previously only owned Cannondale and Gary Fisher bikes, I recently bought my 1st GT, a medium Marathon Sport - I love the i-drive suspension, and I think the Marathon is a lot of bike for the buck. I'm getting ready to upgrade essentially all of the stock components, but I'm holding off of on that at the moment becuase I'm not sure if I got the right size.
    I'm 5' 7" and 1/2. When I test rode the bike, the LBS only had the small female version of the Marathon on the floor so I test rode that as a comparision knowing that the geometry was a little different than the standard small frame. The LBS associate recommended the medium frame for me; he said I looked cramped on the small frame, but he never checked my standover clearance. The TT lenght on the medium feels comfortable to me, but I have essentially no standover clearance - my crotch barely touches the TT without any pressure, but I can only lift the bike up about 3/4 of an inch. The importance of standover clearance seems to be a matter of much debate based on my online searches, but that mainly seems to be in the roadie realm. I've never had an incident riding where I would've hit the TT, but I don't want to have any opportunities for that to happen! For those of you with more experience than I, particularily with the latest GT frames, do you think I should exchange the bike for a small Marathon? I'm worried that the small TT length would be too short for me; I know I could probably get a longer stem, but I'm worried that handling would suffer a little, and I need all the help I can get to stay on the trail! Your opinions and thoughts would be greatly appreciated!

    Thanks,
    bk

  2. #2
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    Small is way too small for you.
    Go by the top tube length.
    Medium is the right size for you.

    I've only fallen on my side, or gone totally over the bars. You won't ever rack yourself, unless you going really slow uphill and jump off the pedals.

  3. #3
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    Spot on Nato!

    Go off the top tube length first.

    If your comfortable in your riding position, that's the most important thing.

    In 16 years of riding mountain bikes the only place i've ever smacked the boys is on the back of the seat and on the headstem bolt..... both occasions i was well outta shape for that to happen!!!

    Medium is deffinately your size.
    I'm Ron Burgundy?

  4. #4
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    I'm 5' 7" and I have been stuggling with the same thing. I want a force and I have ridden both the small and the medium. I like the top tube length on the medium much better than the small. I also own a Avalanche expert in Medium and find it the most comfortable bike I have ever owned. I mesured the the center of the seat tube to the center of the handlebar stem and the medium force is the same measurment as my Avalanche. So I'm going to get the medium. Stick with the one you have!

  5. #5
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    I have a friend who has racked himself twice on two different races.....but then again he owns a Giant so that explains it. LOL!!! just kidding of course Giants are good bikes, but not great.... I too have not racked myself. I did hit the inside of my leg but that's because my foot came off my pedal. I hope I didn't just jinx myself. You should go for the medium. I have short legs for my height (5'10) and I have no problem with the medium Force which is a little higher than the marathon. Instead of upgrading the components, how come you didn't go with the next level of a carbon marathon? Best of luck to ya.

    GT J
    2009 GT Marathon Team,GT Force 2.0, GT Jelly Belly TT (nude carbon), and a very special Todd Wells Zaskar.

  6. #6
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    bringing this up from the dead:
    Just recently got a GT Marathon sport.
    I am 6'1 and 190. several friends recommended i get the Med frame vs Large. They said that a medium frame is a little smaller but because of that easier to control. The med seems to fit me fine, but the bike store didnt have a large in stock so i couldn't try it.
    Is what they say basically true for my size.. or should i try to exchange for a large frame?

  7. #7
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    At 6'-1" you should deffinitely be on a large frame.

  8. #8
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    Not true about a 6'1" person needing a large Im 6'1" and ride a medium but my inseam is 30.5" so I couldn't put both feet on the ground with a large I did find that it was a little more comfortable with a little bit longer stem on my medium though. All in all I am really happy with my Medium GT, but as anyone will tell you try both and figure out what feels better for you.

  9. #9
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    i ended up exchanging it for a large frame.. feels a little better.. not as cramped.
    i have a 33.5 inseam

  10. #10
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    yeah @ 33.5 I would definately be on a large too but we are all different, glad it worked out for you, enjoy your new GT

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