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  1. #1
    FM
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    Long top-tube + short stem vs. short top-tube + long stem?

    Just curious about others opinions on this.. I've researched the hell out of it, and am pretty confident with my logic, but I'm always curious to hear what people think.

    Looking at "medium" frames, I see horizontal top tube lengths ranging from 22.75 to 23.75".

    So, a 22.75" toptube with a 90mm stem, vs.
    a 23.5 top tube with a 70mm stem.

    roughly the same distance between bars and seat; the difference is in wheelbase & weight bias. Of course seat tube angle and handlebar height are factors (which can be adjusted)... I've thought all this through ad nauseum.

    What say ye, MTBR brothers!?

  2. #2
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    I am not sure that top tube measurments tell the whole story. The the seat tube placement / angle can alter the true frame sizing. I got into a discussion w/ Canfield bikes about misleading frame geometry spec's that don't tell the whole story. I was told a better way to measure a frames actual size was to : make a mark on the floor directly below the centerline of the BB, next from the side of the HT find the center and drop another centerline mark straight down to the floor and make a mark, now measure this distance. This measrment acounts for your feet on the pedals and how much bike you have inf ront of you. My preferance short stems and big bikes.

  3. #3
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    I think after a weekend of riding, you will be used to, and ripping on either option. Find something else to agonize over

  4. #4
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    Some random thoughts from a common idiot:

    I prefer a 70mm stem for anything down or in the air, no doubt.

    Yup, when climbing is involved 70mm ain't so good but you've got to make a choice of which is more important. 90mm stems are not fun to hang onto in the rough steeps.

    I went from a 70 to a 90 recently to get more weight on the front to help out in the corners. You see on XC rides I was getting tired, and not fully shifting some weight to the front for traction with 70 stem. With a 90 stem I can just attack without thought. more on this later....

    One odd thing is... no matter what TT length I get I seem to be able to adapt to a 20mm change in cockpit length quite easily....

    here's what I learned out of it... it's more to do with how a frame is designed to handle that affects things. My bike has a long TT but is designed for a longer stem too .... because the seat angle is slack so it puts more weight back when sitting. Add differing chain stay lengths further complicates the equation.

    Longer chainstays bring shorter top tubes.... so ideal centre of mass may not be influenced greatly by thinking a 22.75" toptube needs a 90mm stem and a 23.5 top tube needs a 70mm stem.

    Standover was all it once

    longer TT length was all it two years ago

    now scrap all that with the new breed.....
    duallies are now being tweeked as duallies should be geometry wise for intended use

    this upsets some equations... I can really dig some shorter chainstays but the bike may need a longer TT and will often come with a slightly longer one. Or, want to eat all the pie then lengthen the chainstays for easy climb with a slightly shorter TT (to appease the expanding wheelbase). In these scenarios I am not sure stem length plays a significant role. Seat angles can play silly buggers like my scenario though...

    Give us the good oil on what seat angles and chainstays you anticipate for your two options.

  5. #5
    FM
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    Quote Originally Posted by All Mountain
    Some random thoughts from a common idiot:

    Give us the good oil on what seat angles and chainstays you anticipate for your two options.
    Good stuff, thanks everybody.

    I got to ride with geolover recently and we discussed in person....

    I know what you're saying about chainstay length- short chainstays make the front end light, so sometimes you need a longer/lower front end to keep the bike balanced. All the bikes I've considered have 17" chainstays.

    I totally agree on stem length- tried everything and I feel a 70mm length is the best for my riding style. Mostly cuz it seems to get the weight not too far in front of the front wheel's axle or behind it. If I needed to run a 90mm+ for all day trail riding, I'd think the frame is too short.

    So I'm stil leaning towards longer TT & shorter stem, seems most agree this is the way for AM/FR riding. Nothing I'm losing sleep over, but more entertaining than TV!

  6. #6
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    Quote Originally Posted by FM
    ....
    I got to ride with geolover recently and we discussed in person....
    did he catch on fire ?~?


    Quote Originally Posted by FM
    ... I feel a 70mm length is the best for my riding style. Mostly cuz it seems to get the weight not too far in front of the front wheel's axle or behind it. If I needed to run a 90mm+ for all day trail riding, I'd think the frame is too short.
    Absobloodylutley

    With my 90 I feel stretch out very XCish... but that's what I'm riding mainly now in the wet winter. When I put the 70 on I still feel good but ready for action !~!

  7. #7
    Nightriding rules SuperModerator
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    I am jumping back and forth on this... in my case with an 80mm and a 100mm stem (the M 575 is a tad short for me I think ) now that I got a On One Inbred with a 23.7" TT I enjoy having the short stem there.. a lot... on the 23.4" 575 I used the 80 a bit.. but was way too short for any extended climbing.. it felt harder and got tired faster... so the 100mm X4 went back on the 575 and the 80 is now on the Inbred.... maybe next time around I will get a trail bike with a 24"+ TT and use shorter stems....

  8. #8
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    front/ center

    to measure the center of BB horizontaly to the center of front axle NOT the head tube(canefields suggestion) is called front center... something BMX'ers have refered to for years. This measurement will change with fork lower leg lengths, trail and rack. alsosee some frame makers who use 1.5 head tubes and 1.1/8 reducers with inset cups to lower headtubes, effectively shortening the front/ center. Front/ center effects the bikes center of gravity.
    depending on how bored I am today, I may generate a compairison based on those manufaturers websites who show F/C in their geo charts. wondering if there is a common F/C out there for any given amount of travel or purpose bult bikes

  9. #9
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    Generally for XC riding a 100mm stem is ideal. So pick a frame that fits you with a 90-100mm stem. A 7deg. or 10deg is what I have used over the years.

  10. #10
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    Quote Originally Posted by sneakyracer
    Generally for XC riding a 100mm stem is ideal. So pick a frame that fits you with a 90-100mm stem.
    I agree. From my experience, I find that anything less than 90mm causes the steering to be too twitchy and compromises climbing (for general xc riding).

    I'm 5' 11.5" and ride a medium Yeti 575 (23.4" top tube). I used to own a large 575 but in order for me to have the right cockpit, I ended up with a 75mm stem and didn't like the way it handled, except for really steep downhill stuff. My medium has a 110mm stem on it and it feels great...except for really steep downhill stuff. On steeper stuff I sometimes wish for a slightly longer tt (23.75 would be perfect) so I could run a 90mm, but I'd still take my M 575 over a L 575 any day. With the right body english, I can still roll everything I could ride before. Plus, the shorter wheelbase has helped me clean some tight switchbacks that I never could clean before.

    For the type of riding I do, a shorter top tube and slightly longer stem (90-110) just works better than a longer tt and shorter stem, but YMMV.
    "If you suck, that means I'm better. The more you suck, the better I am. So. Let me count the ways you suck." - Scribb

  11. #11
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    I'm with the poster who says it really doesnt matter.. Total reach/position is way more important than how you get there.

    Good riders will adjust.

  12. #12
    Five is right out
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    FM- what was the medium frame you found with a 23.75" ETT?

    I'm with AM on the inital statement about the shorter stem being better on rougher stuff. I used to run a 110mm on my medium 575 (I'm 5'10"), but kept going over the handlebars. I now run a 50mm just for confidence on the downhills. The position is a little more upright than I'd prefer, but the benefit is no more random endo-ing. I don't notice any twitchiness and climbing is still fine as I run barends.

    I've just ordered a hardtail frame with a 24.4" ETT, so I can still get a nice stretched-out position with a short stem.

  13. #13
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    Don't forget that if you have wider bars than the effects of a shorter stem on your steering will be less.

  14. #14
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    Stem length is important and shorter is better. I like the 65-80mm and am 6'. You'll find very few people who have tried both (not refering to those who say 'most people use') and like longer stems.

    Short stems absolutely help handling but shorter cockpits can compromise your ability to keep the front tire down when climbing steep pitches if you don't compensate by keeping your chest down. I don't know any good riders who have tried short stems and don't like them more on the same bike that previously fit with a longer stem. Just keep your chest down and pull back on the bars and you'll climb better than with a longer stem.
    2 wheels

  15. #15
    Canfield Brothers
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    The front Center measurment is the best for final size evaluation after you have the fork, frame, headset together. As far as evaluating frame only you can't use it. You need to use HT top center to BB horizontal (I like to call it DH size, standing size) with the head angle measurment. Every fork slightly differs in length and trail measuments. It's important to know all the numbers to effectively know how it will fit when it's together.

  16. #16
    FM
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    Quote Originally Posted by womble
    FM- what was the medium frame you found with a 23.75" ETT?
    Gary Fishers....

    And Larges from sone brands where the mediums are extra short...

  17. #17
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    Quote Originally Posted by All Mountain
    did he catch on fire ?~?
    No, he did not catch on fire! The trail we rode was SWEET though and I can't wait to go back!

    I think FM is crazy to get a large, but it's your money. Damn, I should have let you ride the SuMo...pretty similar numbers to the bike you're looking at...23.8"TT...70mm stem...shorter chainstays though....
    Last edited by geolover; 06-21-2007 at 12:14 PM.
    Extreme stationary biker.

  18. #18
    FM
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    Quote Originally Posted by artnshel
    Stem length is important and shorter is better. I like the 65-80mm and am 6'. You'll find very few people who have tried both (not refering to those who say 'most people use') and like longer stems.

    Short stems absolutely help handling but shorter cockpits can compromise your ability to keep the front tire down when climbing steep pitches if you don't compensate by keeping your chest down. I don't know any good riders who have tried short stems and don't like them more on the same bike that previously fit with a longer stem. Just keep your chest down and pull back on the bars and you'll climb better than with a longer stem.
    This is exactly my opinion too, having tried everything bewteen a 50 and 130mm. Of course, the "XC" riding I do involves jumps, drops and skinnies, and the rides are usually under 20 miles... so I'm more concerned with handling than with efficiency. Basically the reason I'm asking all this, I'm going to try a large frame with a 23.75 top tube so I can run a 65mm stem and still get stretched out enough to do long climbs comfortabely. The long wheelbase and seat tube also appeal to me since I am "in between" sizes.

  19. #19
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    fwiw

    I read an article sometime back this fella out in CO wrote.... Apparently he is a guru to the degree he holds camps for riders...anyway:

    He preaches shorter stems.....so I went out and got a 45mm just to see....this may be important I guess: I ride a XL '05 Heckler, Minute 20mm @ 140mm fork, Cloud Nine rear shock, 2.35 UST Spiders, Thompson Lay-Back seat post with seat adjusted half down rails, Azonic 45mm stem, 28" 31.8 bars- I weigh #260 and stand 6'3', and ride between XC and AM...

    The guru's contention is that a riders weight should only be a few pounds more than what is required to steer while riding any particular condition....in other words it is my comprehension of that statement that you should be light on the bars and front end.... He also says (which is obvious) the closer you are to the steer tube the more control you have over the front of the bike, which comes in handy for bunny hopping and lifting the front end while technically climbing (roots, rocks and such) and more than a few other situations...

    The dude was dead on in my case... Changing to a shorter stem has drastically improved my technical riding abilities.....understand I dropped from a 110 and 120mm to the 45mm now, but I have greater control, less fatigue on long rides, and just as much power to the pedal as before- The only thing lacking is keeping the front end down while climbing steeps- I have compensated for that though with body position...

    imHo the most important body geometry is that of seating position over the pedals- you gotta have that leg extension and that plumb-bob drop from your knee to the center of your foot arch when in the 3 o'clock position.... if you don't you are not working the largest most powerful muscles, if you do there is much less effort to do the same thing..... that being said, the little hint the guru dropped about being light on your bars has again, made me a much better technical rider, and that is easier with a shorter stem....

    my opinion anyway.

  20. #20
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    Lee of www.leelikesbikes.com is all about shorter stems. He runs a 50mm on all of his bikes. He figures stem length is most important when going down. When pedaling up you'll adapt to whatever you have on there and stem length isn't as important.

  21. #21
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    I don't find a short stem to create twitchy steering at all.
    Like was said, handlebar length is a big factor, don't forget fork height, HA, etc, etc.

  22. #22
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    70 stem (or less) and 710 bars

  23. #23
    FM
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    Quote Originally Posted by All Mountain
    70 stem (or less) and 710 bars
    word yo

  24. #24
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    I recently went from a 120mm stem to a 80mm stem on my cannondale rush. I'm worried because I was very stretched out on it and was having issues with the front coming up. Now with the short stem I'm not as stretched out, but I'm worried the front may come up even easier.

  25. #25
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    zombie thread! shoot it! shoot it!

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