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  1. #1
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    How to fit frame size to a person's height?

    It's embarrasing that I've been riding for so long, yet don't know how to tell if my bike really fits me or not.

    I'm 5'6" and bought an 18" framed Trek 8000 back in the 90s. That bike was always comfortable and seemed about right for me. I would sometimes wish for a lower bar if I going out of shape going uphill, but overall it was a good stable bike.

    I later bought a Trek 8500 with the Fox fork and disc brakes. This was a 16.5" frame and it felt kind of smallish to me, but was lighter and seemed to be ok. It's a great bike, but looking back, think it was a big mistake. My weight ends up being too much over the front wheel, and I've clobbered my nuts on the goose neck before.

    Anyway, do you frame size a mountain bike like you do a road bike by the distance of the bar to your crotch? ...and if so, what are the prefered measurements?

    Thanks.
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  2. #2
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    Frame sizes differ from manufacturer to manufacturer. The 16.5" measurement you reference is the distance from the center of the bb shell to the top of the seat tube. Some manufacturers measure to the middle of the top tube, where it intersects the seat tube, rather than the top of the seat tube. Also, the angle of the top tube, or how sloped it is, changes that measurement.

    When fitting a bike, the first thing to do is get the saddle height and setback (distance back from bb shell) set so that you are positioned properly in relation to the cranks. Then adjust reach by changing stem length. Once you have these measurements, you can look at a bike's geometry chart, and decide if it will fit you or not, without regard for the frame's actual "size".

    On your current bike, you said you feel like your weight is too much over the front wheel. Where is your saddle setup? Is it adjusted all the way forward? Most people adjust "reach" by moving the saddle forward or back, which could totally mess up their position over the pedals. Saddle adjustment is for position over pedals. Stem length changes reach.

    Distance from bar to crotch is important for protecting the family jewels, but really isn't a good reference for bike sizing.
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  4. #4
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    Thanks,

    I guess I'll have to find out correct positioning over the pedals as a start.

    Here is the bike I'm talking about. I guess without me sitting on it, it doesn't do you any good.

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    I guess everyone is different but im 5'10" and have been riding a trek 9700 16.5" frame for the past 12 years and feel totally comfortable on it, in and out of the trails. i also road a trek 6500 17.5" for a few years and felt very good on it as well.

  6. #6
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    The first thing you need to figure out is your effective top tube length of the frame, and horizontal stem length, and see if that fits your body.


    FWIW, 18" seems too big for someone 5'6"....assuming it was not a cramped frame. I don't think the Trek 8500 comes in a 16.5" Do you mean 17.5"? I guess you have a short torso, long arms and long legs. I'm 5'11" w/ 32" inseam and I generally ride a 16.5"-19" bike depending on brand. ETT is much more important than stand over height, but oddly manufacturers size by height.

    Here is one of many calculators to size you up. You can just pick a frame at the end, then correspond the bike geometry to make it into absolute measurements.

    http://www.competitivecyclist.com/za...LCULATOR_INTRO

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    from looking at the pic of the bike i think a shorter stem would help out if you feel the bike is to big for you. nice bike by the way i love these older treks.

  8. #8
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    Quote Originally Posted by IAmHolland
    The first thing you need to figure out is your effective top tube length of the frame, and horizontal stem length, and see if that fits your body.


    FWIW, 18" seems too big for someone 5'6"....assuming it was not a cramped frame. I don't think the Trek 8500 comes in a 16.5" Do you mean 17.5"? I guess you have a short torso, long arms and long legs. I'm 5'11" w/ 32" inseam and I generally ride a 16.5"-19" bike depending on brand. ETT is much more important than stand over height, but oddly manufacturers size by height.

    Here is one of many calculators to size you up. You can just pick a frame at the end, then correspond the bike geometry to make it into absolute measurements.

    http://www.competitivecyclist.com/za...LCULATOR_INTRO

    Thanks, I'll check it out. The bike is at least 10 years old, and that's what I bought the bike as, although I never actually measured it. I have an 18" inch frame Trek aluminum 8000 from the 90s and that bike to me feels more comfortable and stable, but then too, it has a rigid fork. The only place I don't like that bike is on uphills where I have to get off fast.
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    Wow! I measured my Trek and the result is not what I expected.

    For some reason I thought this 8500 was a 16.5". The thing measures out to be 15" (could be 15.5") if I am measuring right. I am going from the center of the crank to where the seat post slips in. There is a clamp there that I need to loosen to get a perfect measurement. The center bar measures 33" at the headset, 30" in the middle and 27" at the seatpost. My inseam is 31", so it's really a good fit there.

    Once I get some assistance, I'll go through that measurement process and see if this frame size matches up.
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    Pics of you on bike with pedals at 9 and three please .

  11. #11
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    Bike Fit calculators are very fussy about the measurements you take. You can end up with some fairly silly recommendations from them.
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    A bigger size bike will always be more stable and a smaller one more agile. FWIW, XC racers prefer smallish frames as evidenced by a lot of seat post showing.

    As to your question about road vs mountain sizing, generally, a small size road bike will have shorter top tube than a size small mountain bike. As an example, typically a size small road has 52.5 cm (20.66 inches) top tube while a size small mountain has 22 inch. On (mountain) flat bars you only have one hand placements while drop bars have three - (top, hoods, and drops) all of which have different measurements to saddle. Each of these hand placements affect how your weight is distributed, how aero dynamic your position and relative to your flexibility, which position is more comfortable.

  13. #13
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    Quote Originally Posted by Dr. Tweedbucket
    Wow! I measured my Trek and the result is not what I expected.

    For some reason I thought this 8500 was a 16.5". The thing measures out to be 15" (could be 15.5") if I am measuring right. I am going from the center of the crank to where the seat post slips in. There is a clamp there that I need to loosen to get a perfect measurement. The center bar measures 33" at the headset, 30" in the middle and 27" at the seatpost. My inseam is 31", so it's really a good fit there.

    Once I get some assistance, I'll go through that measurement process and see if this frame size matches up.
    Frame size is often measured from the center of the bottom bracket to the center of the top top (were it meets the seat tube) often CC (center to center)
    Or from center of bottom bracket to top of seat tube CT (center to top)

    I am guessing the 33" 30" 27" refers to stand-over height. Often measured in the center of the top tube or 12" from it. In your case 30"
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    Front center or effective top tube measurements are the relevant numbers , stand over and seat tube length are virtually useless as long as you can physically stand over the bike . Cockpit , reach to the bars , effective top tube , these are the things that will get you centered on the bike . Pics of you on bike with pedals at 9 and 3 would help make this a quick resolution .

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    Get your feet, knees and butt in the right place

    and show us a photo with you on it and then we can talk. Otherwise we are just chasing our tail.

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    How close your knees are to your handlebars, both while seated and standing and hammering, is a good primary indicator.

  17. #17
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    Quote Originally Posted by Berkeley Mike
    and show us a photo with you on it and then we can talk. Otherwise we are just chasing our tail.

    Quote Originally Posted by AZ.MTNS
    Pics of you on bike with pedals at 9 and three please .

    I'll take one and post it tomorrow.
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  18. #18
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    Ok, 3 and 9 oclock on the 15" 8500 and the 17.5 dinosour 8000.











    .... and no snarky remarks on the blue jeans, I'm working on getting some good riding gear


    The 8000 feels much more stable to me than the 8500, maybe slower steering or less twitchy is a good description.
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    Thank you for the pictures!

    So define for me, now that you have brought this forward and kicked it around a bit, what your question is. Are you asking about what size bike you should be riding or are you asking about whether these bikes fit you?

    My question for you is, then, what does my answer do for you?

  20. #20
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    The "dinosaur" bike looks like a much better fit , the longer top tube would make it feel more stable . A flatter stem might be more appropriate for a "racier" position . IMHO the 8000 is too small . Position over the pedals on the "dinosaur" bike looks pretty good , its personal preference , but your close .

  21. #21
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    Quote Originally Posted by Berkeley Mike
    So define for me, now that you have brought this forward and kicked it around a bit, what your question is. Are you asking about what size bike you should be riding or are you asking about whether these bikes fit you?

    My question for you is, then, what does my answer do for you?

    I'm asking if the 8500 is too small for me and taking the pic was a great idea.... I look like I'm on a kids bike (almost).


    Quote Originally Posted by AZ.MTNS
    The "dinosaur" bike looks like a much better fit , the longer top tube would make it feel more stable . A flatter stem might be more appropriate for a "racier" position . IMHO the 8000 is too small . Position over the pedals on the "dinosaur" bike looks pretty good , its personal preference , but your close .


    Thanks man! I appreciate your opinion... it backs up what I am feeling when I ride the bike.
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    You look more comfortable on the 8000

    but your seat position looks a bit far back, possibly due to the clips. Your feet are too far back on the pedals, definitely due to the clips. That means you are having to push the pedals in a funny way from behind. I think this leaves you stretched out and that takes away a nice elbow bend we use for dynamic positioning on the bike. It also limits your ability to get behind the seat. It limits your ability to accommodate handling circumstances and you are stuck in a position of tension pulling you apart. You may be accustomed to that but really missing out on good power delivery and balance.

    The 8500 is too small.

    The 8000 May be a touch big but fit on the bike will mitigate that.

    The foot/seat position threw me off. I guess what it revealed is "fit" and "bike size" have to be interpreted at the same time. How to weigh these things is why I asked for clarification.
    Last edited by Berkeley Mike; 09-05-2010 at 01:45 PM.

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    You do look big for that frame but since it's yours I have a few ideas to stretch you out a bit. You need to try a seatpost with a little setback, the one your using has none. Also unless it's an opticle illusion or a different style bar it looks like you have the handlebar rolled way back crowding the cockpit, roll it forward.

    Also swap that last shim and raise your stem so there are no shims on top of the stem, try these things and check back.

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    Yeah, those bars are swept back slightly. Makings some adjustments may be worthwhile just to see...

    If I end up buying a larger frame, I'm thinking of splitting the difference between the bikes. The 8500 is a 15.5" frame (even though I measured 15.25"). The 8000 is a 17.5" frame. I may go to the local dealer and try out a 16.5" framed Trek to see how that feels.
    I could probably be happy with a 16.5 or 17.5 with that brand.

    Thanks again.
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  25. #25
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    Quote Originally Posted by Bammer
    You do look big for that frame but since it's yours I have a few ideas to stretch you out a bit. You need to try a seatpost with a little setback, the one your using has none. Also unless it's an opticle illusion or a different style bar it looks like you have the handlebar rolled way back crowding the cockpit, roll it forward.

    Also swap that last shim and raise your stem so there are no shims on top of the stem, try these things and check back.
    +1 Considering you all ready have the 8500 (15") I would also suggest also that you try an offset seat post, roll the handle bars forward as suggested but I think you should flip the stem to lower the frond end and put you in a "racer" position. It is also a good idea to check your seat height many people have the seats to low, try raising it 0.5 of and inch. You could also try a longer stem maybe 110 to 115mm max. A good local bike shop should let you try before you buy and also give bike fit advice. (longer stems just slow the steering down. I have a 115mm on one of my bikes which was standard and it rides ok. Most likely I will swap for a 100 to 110mm)
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  26. #26
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    pretty sure the 8 series doesn't have a 16.5

    your riser handlbar should have an upsweep and a backsweep. make the up part straight up and down. that will put you more upright though but give you more horizontal space. flip the stem, as others said. you can get more stretch in the racer position, as others said. the distance increases as you increase the difference in height positions.

    i'd go for a 120mm stem if i were you, with 6 rise and a flat bar. what is your current stem?

    http://www.habcycles.com/fitting.html has a visual on how angles affect length. you can also see how a riser bar (what you have) affects/equates to other stems.

    as you are now seeing, and has been noted by all, the effective top tube length is the important part for fit, not the standover height.

    8500 looks a bit small, but the seat position (to me anyway) seems fine. 8000 looks a tad large, and you are sitting a bit too far back.

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    It can't be both

    If the seat position on the 8500 is okay, an assumption with which I do not agree, the a set-back seat post is a mistake. In my view it makes things worse. Messing with a stem and bar to spread you out over the 8500 will make it ridable but hardly optimal.

    If you are open to another bike/frame which is a bit smaller than the 8000 that is the route I would recommend. As people here have indicated the frame size as given by the manufacturer is not particularly useful. A better indicator is something called Virtual Top Tube (VTT). This is calculated by measuring the distance from the center of the top of the head tube along a horizontal line to the center of the seat post.

    The bikes pictured below, a 1995 Bontrager Racelite and a 2010 Yeti Arc, show very different geometries. The seat post sizes are 21.25 and 19.75 respectively. Further the head tubes are at different heights due to the difference in shocks used. Subsequent wheel bases and front wheel trail are very different. Yet can both fit the same person with a VTT of 24 and 24.4 respectively.

    Just about any bike can create a seat height to fit a larger person with a long seat post so seat tube measurements become irrelevant. Fore and aft seat positions can be mitigated, too as rails allow for that adjustment and setback seat posts are available. Both of these can be adjusted for good power delivery. But what about the upper body and clearance in the cockpit?

    In your case you are too far back on the 8500 to begin with yet your hands are way too close to your knees. Heck, as you said you have already hit it, the topcap is too close to your knees. A longer stem will do nothing for that.

    The pictures told us a lot instantly. Take at VTT for each of the bikes and lets see what that tells us.
    Attached Thumbnails Attached Thumbnails How to fit frame size to a person's height?-ebonti852.jpg  

    How to fit frame size to a person's height?-eyeti650.jpg  


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    Quote Originally Posted by Dr. Tweedbucket

    My weight ends up being too much over the front wheel, and I've clobbered my nuts on the goose neck before.
    While I agree flipping/lowering the stem or buying a longer one would help him stretch out it would also make the situation above worse, he needs to raise it to push his weight back from the front wheel.

    Although your bike is a bit small and you may want to buy another frame, you really should try the recommendations above. They will easily add 4 inches to your cockpit, I know it will make a big difference. Then again buying a new bike that fits better is always a good idea if you have the coin.

  29. #29
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    Quote Originally Posted by Bammer
    While I agree flipping/lowering the stem or buying a longer one would help him stretch out it would also make the situation above worse, he needs to raise it to push his weight back from the front wheel.

    Although your bike is a bit small and you may want to buy another frame, you really should try the recommendations above. They will easily add 4 inches to your cockpit, I know it will make a big difference. Then again buying a new bike that fits better is always a good idea if you have the coin.
    In another thread a poster was complaining about lack of bike fit and sore hands.He stopped the sore hands by moving his seat back and lowering is handle bars. here
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    Quote Originally Posted by Berkeley Mike
    If the seat position on the 8500 is okay, an assumption with which I do not agree, the a set-back seat post is a mistake. In my view it makes things worse. Messing with a stem and bar to spread you out over the 8500 will make it ridable but hardly optimal.

    If you are open to another bike/frame which is a bit smaller than the 8000 that is the route I would recommend. As people here have indicated the frame size as given by the manufacturer is not particularly useful. A better indicator is something called Virtual Top Tube (VTT). This is calculated by measuring the distance from the center of the top of the head tube along a horizontal line to the center of the seat post.

    The bikes pictured below, a 1995 Bontrager Racelite and a 2010 Yeti Arc, show very different geometries. The seat post sizes are 21.25 and 19.75 respectively. Further the head tubes are at different heights due to the difference in shocks used. Subsequent wheel bases and front wheel trail are very different. Yet can both fit the same person with a VTT of 24 and 24.4 respectively.

    Just about any bike can create a seat height to fit a larger person with a long seat post so seat tube measurements become irrelevant. Fore and aft seat positions can be mitigated, too as rails allow for that adjustment and setback seat posts are available. Both of these can be adjusted for good power delivery. But what about the upper body and clearance in the cockpit?

    In your case you are too far back on the 8500 to begin with yet your hands are way too close to your knees. Heck, as you said you have already hit it, the topcap is too close to your knees. A longer stem will do nothing for that.

    The pictures told us a lot instantly. Take at VTT for each of the bikes and lets see what that tells us.

    The Yeti has a set back seat post. I am not sure why you are so anti set back seat posts. KOPS seems to have gone out of favor as a "set" rule of bike fit. It seems up to about an inch behind the pedals seems to be acceptable. Several custom bikes i have seen posted on this forum have off set seat post fitted. As to a slightly longer stem depending on the style of riding you undertake can still deliver acceptable handling just different.

    I agree that the OP probably needs a frame bigger than the 15 inch 8500.

    Time and time again I see on this forum that VTT is all important. The general consensus given often seems to be to go with the bigger frame which I don't think is always the best solution. An article I read on bike fit said you can make a smaller frame fit (to a small degree) but a frame that is to big will always be too big. The advice was to always go with the smaller frame.
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    Delete double post.
    Last edited by mitzikatzi; 09-06-2010 at 09:17 PM.
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    I can easily flip the bar stem and try that. How much of a setback on the seat post would you guys recommend? On this bike, it seems when I am up off the seat, the feeling is too much of my weight ends up over that front wheel and that's what I don't like about it, so I'm not sure this is going to be a fix. The top tube length seems like the key here.

    I've been pricing used frames and Trek did make a 16.5, but I am kind of leary on buying a used aluminum frame .... hard to tell what all it's been through.
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    Quote Originally Posted by Dr. Tweedbucket
    I can easily flip the bar stem and try that. How much of a setback on the seat post would you guys recommend? On this bike, it seems when I am up off the seat, the feeling is too much of my weight ends up over that front wheel and that's what I don't like about it, so I'm not sure this is going to be a fix. The top tube length seems like the key here.

    I've been pricing used frames and Trek did make a 16.5, but I am kind of leary on buying a used aluminum frame .... hard to tell what all it's been through.
    Most seem to be about an 1 inch. See if you can borrow one. I wouldn't just buy one to try.
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    Quote Originally Posted by Dr. Tweedbucket
    The top tube length seems like the key here.


    Exactly , top tube length is everything . If your position over the pedals is correct , you do not need a setback seat post . FWIW , Berkley Mike gave you some very solid advice . The force is strong in his advice , you may want to read it again .

  35. #35
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    small correction. the effective top tube length is important. there is an actual top tube length as well, which is the real length of the tube, but since it's angled, it's not the effective length.

    I must admit to being confused. I think the seat position on the 8500 is better, at least for me. I played with slightly behind as well, but I feel more effective a little slightly more forward. Of course, I have no empirical evidence (I don't time myself as that's not why I ride). I just feel less drained on certain rides.

    Mike, however, indicates that you are too far behind on the 8500 and the 8000....so you should be positioned in front of the pedals???

    I don't think your weight balance issue when you stand can be resolved entirely on measurements. When you are mashing it uphill, you're going to lean forward some. When you go downhill and stand, you'd need to lean back to ensure you are not going weight forward. Just MO, which can be entirely wrong, but it's what I do.

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    Good eye

    Quote Originally Posted by mitzikatzi
    The Yeti has a set back seat post. I am not sure why you are so anti set back seat posts. KOPS seems to have gone out of favor as a "set" rule of bike fit. It seems up to about an inch behind the pedals seems to be acceptable. Several custom bikes i have seen posted on this forum have off set seat post fitted. As to a slightly longer stem depending on the style of riding you undertake can still deliver acceptable handling just different.

    I agree that the OP probably needs a frame bigger than the 15 inch 8500.

    Time and time again I see on this forum that VTT is all important. The general consensus given often seems to be to go with the bigger frame which I don't think is always the best solution. An article I read on bike fit said you can make a smaller frame fit (to a small degree) but a frame that is to big will always be too big. The advice was to always go with the smaller frame.
    Actually we use it because we own it and the "fit" by the man we use for our team could be accomplished without it. At the end of building the bike I just ran out of money. These guys race and I have learned to listen to them. I think a set-back on a custom ride might work for a certain type of riding but my racers attack and get on top of their pedals for power and handling.

    KOPS out of favor? It is easy to say but I don't think so. I've been using a plumb bob, a compass and ruler for years. Now we have this really cool computerized fitting system and it still comes out the same. I keep hearing people say KOPS is dead over the years but it is still a great starting point for our team usage.

    To the point though, the set-back post was suggested here to deal with a very poor fit. That the OP is interested in another bike takes that out of the question.

    As to the VTT; it is simply a more useful number to use than a size given by different manufacturers. With a VTT measurement at least you are comparing apples to apples. After that you need to deal with seat tube angle, seat position, cleat placement. No matter what bike you get on, no matter what the seat tube "size", you have to do that. After that you have to deal with how far the head tube is from you. That is where VTT gets you much closer.
    Last edited by Berkeley Mike; 09-07-2010 at 12:11 PM.

  37. #37
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    Quote Originally Posted by Berkeley Mike
    Actually we use it because we own it and the "fit" by the man we use for our team could be accomplished without it. At the end of building the bike I just ran out of money. These guys race and I have learned to listen to them. I think a set-back on a custom ride might work for a certain type of riding but my racers attack and get on top of their pedals for power and handling.

    KOPS our of favor? It is easy to say but I don't think so. I've been using a plumb bob, a compass and ruler for years. Now we have this really cool computerized fitting system and it still comes out the same. I keep hearing people say KOPS is dead over the years but it is still a great starting point for our team usage.

    To the point though, the set-back post was suggested her to deal with a very poor fit. That the OP is interested in another bike takes that out of the question.

    As to the VTT; it is simply a more useful number to use than a size given by different manufacturers. With a VTT measurement at least you are comparing apples to apples. After that you need to deal with seat tube angle, seat position, cleat placement. No matter what bike you get on, no matter what the seat tube "size" you have to do that. After that you have to deal with how far the head tube is from you. That is where VTT gets you much closer.

    Thanks a lot for your time, I'm going to ditch this 15" frame, or maybe the entire bike and buy something else. I honestly never realized there was such a science behind fitting a bike ( I was always told it was always as simple as top bar to crotch ). If I stay with Trek, I think a good starting point would be to seek out a 16.5" if they make one, otherwise will have to dig in deeper.
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  38. #38
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    My opinion, you can fit in the smaller frame.

    Your posture has you stooping down to handler bars that are too low for your body. The shorter top tube makes this so . That stem on the smaller frame has no spacers underneath. Its maxed out at the headset. Try switching the stem and that silver spacer for more height. And the stem could use a lot more rise. Can you try other stems? Can you switch the stems from both bikes just to try 'em?

    When you raise the handle bars, you will have a more upright body position. That moves the weight off your arms and more on your behind. Youve hit the stem with your gonads because your weight is too far to the front. When you hit something, the weight shifts even more and you launch.

    Try it. At 5'6" you should fit a frame from 15 to 17 with a 22 inch top tube, give or take.

  39. #39
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    did rotating the bars to the proper position for a riser bar help? Riser bars have an upsweep and a backsweep. It's currently rotated to have the upsweep as a backsweep, and the backsweep as a downsweep...and hands in a funny position.

    It's a 5 minute fix and would help you immensely.

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    You get some weight savings and a more rigid triangle with a smaller frame. It's worth the effort if you can fit.

  41. #41
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    I agree with Bings comments, sounds like its going to be fine

  42. #42
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    15.5 Trek Fuel EX
    5'6" Rider
    29.8 inch inseam
    with a stem that has about 2 inches worth of spacers
    7 degree rise and 90 cm long stem

    for KOP, I dont seem to need the set back seat post I installed. 1 inch behind, setback set post is needed to mount the saddle on post without pushing it forward too much.

    I can balance on my butt just by thinking about it



    in comparison, note how you are bent over a bit more with more mass forward of the BB.



    on my medium size 17" HT, I am bent forward as much as you are, but my butt is much further back from the stem. This distributes the weight more to the rear, than on the smaller frame. I have a 50 cm stem on that particular bike.

    I like the smaller frame as its easier to work the cockpit, the bike feels a lot more responsive to pedal input and I have a better vantage point looking forward (add less neck strain).

    Try switching the spacer location and that advice about turning the riser handler bars. You dont need much height to change the angle of the dangle
    Last edited by bing!; 09-08-2010 at 12:14 PM.

  43. #43
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    Quote Originally Posted by bing!
    15.5 Trek Fuel EX
    5'6" Rider
    29.8 inch inseam
    with a stem that has about 2 inches worth of spacers
    7 degree rise and 90 cm long stem

    for KOP, I dont seem to need the set back seat post I installed. 1 inch behind, setback set post is needed to mount the saddle on post without pushing it forward too much.

    I can balance on my butt just by thinking about it



    in comparison, note how you are bent over a bit more with more mass forward of the BB.



    on my medium size 17" HT, I am bent forward as much as you are, but my butt is much further back from the stem. This distributes the weight more to the rear, than on the smaller frame. I have a 50 cm stem on that particular bike.

    I like the smaller frame as its easier to work the cockpit, the bike feels a lot more responsive to pedal input and I have a better vantage point looking forward (add less neck strain).

    Try switching the spacer location and that advice about turning the riser handler bars. You dont need much height to change the angle of the dangle

    I do like the features on the bike, so for just a little bit of money maybe I can try the suggestions here and make it work. It would be way less hassle than trying to sell the bike, ship it and then locate another that will work well. I'll see if I can do some work on it this weekend.

    Quote Originally Posted by bing!
    My opinion, you can fit in the smaller frame.

    Your posture has you stooping down to handler bars that are too low for your body. The shorter top tube makes this so . That stem on the smaller frame has no spacers underneath. Its maxed out at the headset. Try switching the stem and that silver spacer for more height. And the stem could use a lot more rise. Can you try other stems? Can you switch the stems from both bikes just to try 'em?

    When you raise the handle bars, you will have a more upright body position. That moves the weight off your arms and more on your behind. Youve hit the stem with your gonads because your weight is too far to the front. When you hit something, the weight shifts even more and you launch.

    Try it. At 5'6" you should fit a frame from 15 to 17 with a 22 inch top tube, give or take.

    I actually have some different bars that have about a 2" rise, maybe I can try that first rather than stealing the stem off the other bike. Too, I'll have to see if I can slide that seat back any more, or maybe just pick up a 1" offset post.


    Quote Originally Posted by IAmHolland
    did rotating the bars to the proper position for a riser bar help? Riser bars have an upsweep and a backsweep. It's currently rotated to have the upsweep as a backsweep, and the backsweep as a downsweep...and hands in a funny position.

    It's a 5 minute fix and would help you immensely.

    Good idea too, I'm going to be busy this weekend. Your idea will be the first and quickest to try!
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    Whoops, can't delete a post huh

    I took the day off work to do some stuff and messed around with the bike. See the post below...
    Last edited by Dr. Tweedbucket; 09-09-2010 at 09:27 AM.
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    ok, if I understood you guys right, I swapped a few things around and test rode the bike again.

    I swapped the shims from the top of the gooseneck to the bottom.

    I installed some higher rise bars (spares that came with my old 8000).

    I scooted the seat back another 1/2 inch which is as far as it's going to go. It still needs to go back at least another inch.

    With these up and back bars, I was riding on the very back edge of the seat.
    The bike did feel quite a bit better with me being off that front wheel. I should have lowered the seat a tad (I did for the pics). Still when I stand up, I am right over that front wheel, although not as much as before. The only thing that will ever remedy that is a longer top tube. Still, this is a cheap fix and certainly worth a shot. Too bad those new bars are so heavy. Maybe I should get a shorter and higher gooseneck and keep my old light weight bars?

    Here are some fresh GoPro pics ..... they are fish-eyed a bit, but you get the idea.













    So, it that basically what you meant?

    Much more knee to wrist clearance.
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    Yup. I can see how your back is more upright and there is less bending on your wrists.

    Be aware that with a shorter stem, the bar will be closer to your torso, you will need even more stem rise/bar height to keep you body from reaching down for it.

    Seat position should be set for two primary reasons. Sit bone support and Knee over pedal geometry (close, but does not need to be perfect)

    How about trying the bars UP, but not BACK. When you are on a small frame, you need to bend more to reach something low close to you, than something a bit further.

    Looks good. Go ride and see what happens.

  47. #47
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    roll your bars forward. when you go up, you actually increase stem length, giving you more room because you are stretching vertically, not horizontally. The proper riser position is that the bend in the bars is the UP sweep. The grips should be level with the ground. Right now they are angled down at the end, because the bar has both UP and BACK sweep. The BACK sweep is now a DOWN sweep the way you have it angled.



    you can see that when you apply a vertical rise, you are virtually changing the stem length. Much like how you change the rise of the stem, and the horizontal distance shrinks, changing your weight bias. In this case, you don't change the bias, but instead you change your stretch by stretching vertically up.

  48. #48
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    Ok, got it. I was thinking sweeping back a bit would move me back as well, but I'll rotate them up a bit. All I need is an offset seatpost to get that part closer, and I should be ready for a few more miles. Thanks for all the help!
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    Your body is very different from Bings.

    He is short legged, you are not. He sits very upright. His bike, whether he is comfortable or not, is too small, too. This input from this quarter is far too anecdotal.

    A lot of my young racers fall into this size range and I transition them from 13.5 inch frames to 21 inch frames in the time they are with me.

    Been there done that for 10 years.

    Doc, you are losing your way and going in circles. Get a new frame.

    This is my final post on the subject. Good luck.

  50. #50
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    /\ That , I could not agree any more . FWIW , my bars are well below the seat , you cannot use bar height as any benchmark as to fit . It is very easy to see from the pics I requested that the bike is too small , if you don't believe this is true , please go seek out a professional to get properly fit . By the way , I too have been doing this a very long time FWIW. Last post , good luck .

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    I think I began participating in this discussion with a very clear statement...

    "My opinion, you can fit in the smaller frame."

    I did not represent myself as any sort of bike fitting guru. Nor did I propose that my advice would make his bike fit perfectly. .

    Doc, my advice was given to help you fit better, not perfectly. Swap some parts that you already have, adjust a thing or two, and explore. If you read through that advice, at the end of the day you'll be be able to decide if you fixed your problem and all it cost you is elbow grease. If the advice doesnt fix the problem, then you can sit down and assess your situation and move forward.

    Your other option is to not even think, pull out your credit card, and buy a new frame. But then, if you didnt think it over, and did not try things with your current frame, you may end up buying, another frame that does not fit.

    I could be wrong. Shoot, I just got assessed that I'm riding a bike thats too small for me. Maybe he's right. I dont know. What I do know is there is nothing wrong with testing. Specially if it doesnt cost a thing.

    p.s. I try and keep an open mind. So I brought out my HT Cannondale with a 17 inch seat tube and 23 inch top tube and compared it with my Trek, 15.5 ST and 21.7 TT. did some cruising in front of the house. It has to be said that both bikes have been tinkered with to fit me. As I have previously known, I do like my smaller frame. Specially when I start moving around in the cockpit for techy sections. Thats why I bought it. I cant seem to move enough to influence the bike as much as I'd like with a bigger frame. It pedals amazingly better too. Where the small frame sucks is climbing torque. It has way too much torque climbing, and this makes me have to move over the bb quite a bit. On the bigger frame, I can sit and grind.

    As with any frame discussion, thats just me
    Last edited by bing!; 09-09-2010 at 10:48 PM.

  52. #52
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    Quote Originally Posted by Dr. Tweedbucket
    Ok, got it. I was thinking sweeping back a bit would move me back as well, but I'll rotate them up a bit. All I need is an offset seatpost to get that part closer, and I should be ready for a few more miles. Thanks for all the help!
    yes, you can move back, but you need to look at the parts. you are shortening your cockpit and then trying to compensate by moving the seat back, and thus losing your seating position.

    i'd rather have a good seat position, and bit more upright than having to shift way back.

    the problem is the shortness. you can compensate your standing weight bias by leaning yourself backwards instead of standing and lurching forward. it can be a bit awkward, but you can do it.

    it seems people are telling you to buy a new bike. *shrug*, sure go ahead, but that shouldn't stop you from making the most of what you have in the mean time. you're not really buying anything, just making adjustments...which is free except for time. you *need* to do this, for yourself. this is time to invest in your own knowledge of your necessary measurements. This is so you know what you would like instead of listening to joe schmoe salesman trying to make a profit.

  53. #53
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    Well, the bottom line is, this bike bit me hard twice in a year (ER both times), so while I'm slowing down and making a lot of adjustments, I'll still test ride some larger framed bikes and see how they feel in comparison. I'm sure going up one size would be to my liking, and I'll probably go that direction, but in the mean time, I appreciate the adjustment advice. At least I can use the bike through the end of the season here and then work something else out for next year.

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    Tweed - listen to Berkeley Mike, and AZ.MTNS
    The 8500 is too small.

    We are similar in height, I'm 5'6.5" I tend to like frames with an ETT around 22.5" and can make anything from 22" to 23" work.

    This geometry chart shows a good diagram on how it's measured, it's "D":
    http://www2.giant-bicycles.com/en-us...llections_id=4

    I'll also add my opinion on rotating riser bars: While you can rotate them forward, or back to slightly compensate fit, I'm in the camp where that's a "no-no."
    Sight from behind, level with the bars, front tire straight ahead - rotate them forward, and back - you will see the ends angle up and down - you want them to be parallel to the ground.

  55. #55
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    Quote Originally Posted by deoreo
    Sight from behind, level with the bars, front tire straight ahead - rotate them forward, and back - you will see the ends angle up and down - you want them to be parallel to the ground.
    bingo.

    it's currently rotated into the cockpit. put it in it's proper position and leave it. it's just awkward right now.

  56. #56
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    Quote Originally Posted by deoreo
    Tweed - listen to Berkeley Mike, and AZ.MTNS
    The 8500 is too small.

    We are similar in height, I'm 5'6.5" I tend to like frames with an ETT around 22.5" and can make anything from 22" to 23" work.

    This geometry chart shows a good diagram on how it's measured, it's "D":
    http://www2.giant-bicycles.com/en-us...llections_id=4

    I'll also add my opinion on rotating riser bars: While you can rotate them forward, or back to slightly compensate fit, I'm in the camp where that's a "no-no."
    Sight from behind, level with the bars, front tire straight ahead - rotate them forward, and back - you will see the ends angle up and down - you want them to be parallel to the ground.


    Yeah, it's been a tough lesson learned believe me. I'll have to measure the 'D' spec on the 8500 and then again on the 8000 and then shoot for something in between. I took it out on a ride today, but am taking it pretty slow. It's better with the adjustments, but still has that twitchy, unstable feeling (mainly at slow speeds). I'll go bike or at least frame shopping this winter and try to get something together by next spring. I need to buy a new furnace first.
    Mountain bike riding is the new dirt bike riding. It's cheaper and you don't get shot at as often.

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