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  1. #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.

  2. #27
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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  


  3. #28
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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.

  4. #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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  5. #30
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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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  6. #31
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    Delete double post.
    Last edited by mitzikatzi; 09-06-2010 at 09:17 PM.
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  7. #32
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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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  8. #33
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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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  9. #34
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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 .

  10. #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.

  11. #36
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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.

  12. #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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  13. #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.

  14. #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.

  15. #40
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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.

  16. #41
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    I agree with Bings comments, sounds like its going to be fine

  17. #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.

  18. #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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  19. #44
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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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  20. #45
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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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  21. #46
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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.

  22. #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.

  23. #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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  24. #49
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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.

  25. #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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