1. The most important thing about buying a new bike is to make sure it fits. The only way you'll know if the bike is right for you is to size up the bike and make sure that the bike's geometry matches your body's geometry. Ask questions and do some research.
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2. If possible, try to find a shop that will let you demo the bike on real dirt. Five minutes in a parking lot won't cut it. You wouldn't buy a car without a real world test drive, and a bike should be no different.
3. Don't belive the hype. Just because your favorite rider or best friend rides a certain bike, that doesn't mean that's the best one for you. Have an open mind and be realistic about your needs and ability.
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  1. #1
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    Question about sizing

    Are there any easy ways to make a small frame a bit larger, or more comfortable for the rider?

    Say the rider was on the edge between a small and a medium frame....what could he do?

    Would getting an angled seat post help?

    Is there anything you could do to the stem to stretch the handle bars out further away from the rider?


    Thanks

  2. #2
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    Reputation: Bikinfoolferlife's Avatar
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    Best to have the right size frame of course (not every frame labeled small vs medium are the same). You can use a layback seat post (the post doesn't have to be angled, just the saddle rail clamp position needs to be set back from the center line of the post), but this may not put you in ideal pedaling position. Longer stems or those with different rise could work to make the cockpit length work for you. Some handlebars have more back sweep than others, too. What are the specifics?
    "...the people get the government they deserve..."
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  3. #3
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    the specifics are a 2008 BMC fourstroke 03. Size is 15" frame.

    http://www.bmc-racing.com/fileadmin/..._Australia.pdf

    I found that above link and on the second to last page it lists the geometry specs.

    I am about 5'6" tall, with a 28 inseam.

    I'm thinking the 17" frame would fit me better, but the bike is a very good deal and the seller has stated that his wife (who the bike was for) is 5'7" and fits it fine.

    So I'm trying to figure out if I shouldtry to make this work, or if it is too small. I've contacted a few BMC riders from this forum and others...but keep getting some that say "yea you should fit" and some that say "go with the 17"

  4. #4
    Fat-tired Roadie
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    Wow. Those bikes run really small - looks like about 35mm shorter in the top tube in each size than the numbers I'm used to seeing.

    Fit's pretty personal. But I'd be surprised if you personally fit onto a 15" anything from that brand.

    Sounds like you haven't actually bought the bike? Maybe you should keep it that way.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  5. #5
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    Quote Originally Posted by AndrwSwitch
    Wow. Those bikes run really small - looks like about 35mm shorter in the top tube in each size than the numbers I'm used to seeing.

    Fit's pretty personal. But I'd be surprised if you personally fit onto a 15" anything from that brand.

    Sounds like you haven't actually bought the bike? Maybe you should keep it that way.

    Yea I don't know what to think. I've had a few people think its too small (such as yourself) and a few people that think it should fit fine (including a couple of current BMC owners).

    The seller emailed me back this morning and says that he isn't pushing for a sale, especially if I am unsure about it, but that he is 5'9" and he can "ride this bike comfortably".

    Whether or not that is the truth, I dont know. The guy seems truthful but the data doesn't seem to be adding up.

  6. #6
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    Try the bike and see what you think. If it's too short, you'll feel cramped and upright and you may bang your knees into the handlebars when you try to ride out of the saddle, especially uphill. Ultimately, your opinion's the only one that really matters.

    I think an 80mm or 90mm stem is a really good length, and I'd be concerned about messing up the handling with a longer one. I'm also pretty opposed to messing with the saddle position to improve anything but pedaling health and efficiency. So unless the bike has a really short stem, if it feels cramped there's probably not much you can do about it without messing up the handling or the pedaling efficiency.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  7. #7
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    I agree entirely with AndrwSwitch - you gotta try the bike and see.

    A good deal is only 'good' if the bike is right for you!
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  8. #8
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    The frame specs do look to run on the small side, but why not just test ride it and find out if you like it enough to buy or not? IMO just because I could ride a bike "comfortably" doesn't mean you necessarily would come to the same conclusion...
    "...the people get the government they deserve..."
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  9. #9
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    ok I went to the LBS and I fit best on a 15" specialized hardrock (they didn't have many brands in my size) and a giant boulder in size small (which we measured roughly to 16") and both felt pretty good.

    Measured my inseam at 27.5".

    The 17" Specialized felt a little too big (basically sitting directly on the top tube when standing) as did the Giant sized Medium.

    I also emailed a company (arts cyclery) about the BMC frames and they said it is a bit further and lower, inspired for racing.

    Looking at the numbers of the FS03 and the Giant Boulder...

    Giant seat, tt actual and tt horizontal: 382mm, and 538mm and 555mm
    BMC seat, tt actual and tt horizontal: 381mm, and 518mm and 548mm

    so not much of a difference there.

    Giant wheel base: 1032mm
    BMC wheel base: 1051mm

    So the BMC is a little bit longer overall, but has a shorter top tube. One other thing to note was that the Specialized has a 60mm stem (according to specialized.com) - so If I get something a little larger (as AndrwSwitch suggested above) like a 80mm.... that may put them at almost the same size in regards to distance from the seat tube to the handlebars (20mm longer stem would cancel out the 20/7mm (actual/horizontal) difference in top tube length).

    It makes sense to me, but I don't know if there are some other factors that may come into play with those calculations...

    So it doesn't seem like there is too much of a difference, with the BMC being slightly smaller. I can go try it out and we'll see how it fits.


    Any tips to ensure it fits while I'm down there?...I probably can't practice climbing in this guys driveway, but like someone mentioned above...to make sure my knees don't hit the handlebars when I'm standing up, doesn't feel like your sitting directly over the handlebars, don't feel top heavy, etc.... what else are good indicators?
    Last edited by turbospartan; 04-13-2010 at 05:46 PM.

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