# Long toptube, short stem, why not?



## JoelM (Mar 6, 2006)

After nearly buying a cross bike for the last couple of years, it's time for me to break down and buy one this time. With so many conflicting opinions out there about sizing, it seems to be personal preference more than absolute science. So here are my thoughts which are open for debate. Please note that I'm not saying that anyone is wrong or that I am right for that matter- I'm just throwing this out there to get some feedback. So here goes...

I come from a mountain biking background and ride quite a bit of road these days. The last couple of years I've done cross on my mtb hardtail and been fairly successful. Now that it's time for a full blown cross bike, it seems lots of folks suggest bumping down in frame size while others say to keep it the same as the road bike. The latter seems to make more sense to me. I'm around 5'10.5" and ride a roadbike with 55cm eff tt and a 120mm stem, around 9cm of drop. I've ridden as short as a 54.5 (slightly short) and I could go as long as long as a 56 cm toptube with a 110mm stem, but for the road I like the shorter wheelbase calmed down by the longer stem as opposed to the longer wheelbase excited by the shorter stem. For mountain biking in the last few years, the trend has been the opposite of the typical road setup, that is that most mtb manufacturers set their bikes up with longer tt's and short stems, which works well in my opinion. MTB's with long stems feel goofy, as the average speed is significantly lower and the technical requirements of the trails are significantly higher than what one sees on a road bike. Cross seems to be about smack in the middle in regards to speed and technical difficulty of the terrain. It seems sensible then to go with a setup somewhere in between road and mountain. Why not go with a bike with approximately the same eff tt length as one's roadbike and shorten the stem? The combination of a slightly shortened stem, shorter and shallower bars, and a reduced drop is going to make a bike ride significantly shorter and more upright. A shorter wheelbase may feel like a good thing to roadies, but compare cross wheelbases to that of mtbs which typically deal with significantly more technical terrain than a cross bike. The longer wheelbase adds stability, and slowed handling can be somewhat compensated for with a shorter stem. Running a long stem on a short bike places a rider over top of the bike, possibly to too much of a degree in technical riding, increasing the risk of endos and loss of control in general.
I've gone through a lot of riders setups posted here and elsewhere and it seems that many of those that bump down in frame size end up running a 10mm longer stem (often flipped up to positive rise) to compensate, while those who shoot for approximately the same size roadbike/crossbike shorten their stem slightly. From my experience the shorter stem makes more sense. I've got the choice between two cx frame sizes- one with a 540mm toptube and the other with a 555mm, and as it stands right now the 55.5 seems like the way to go. I'm having a hard time imagining squeezing on a 54cm toptube!

Does anyone agree with this argument? I'm sure quite a few disagree 
I'd like to hear more in-depth opinions on cx fitting since the recommendations cover the spectrum and are often rather terse.


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## javaracer (Aug 8, 2007)

my opinion, is that on a rigid bike, a shorter tt is better as your back is more upright. i'm 6'4' with a long torso and love long tt's but find a shorter cx bike is more comfortable, for bumps, less stress on hands( i've had two carpal tunnel op's)and less wear and tear on low back. dismounts are easier, if you're more upright. i ride my cx bike alot on road 'cause it's so comfy. i do ride 29'rs now, and like the long tt there, but front end is higher and, i'm suspended.


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## alxandl (Aug 23, 2004)

*love it*

My last four cross bikes have had long TTs and and I have had three of them set up with short stems. I find the short stem to be a huge upgrade. I feel more in control and more centered over the bike, which is advantageous in a number of situations, including on bumpy terrain such as the grass at Starcrossed a couple weeks ago. I ride mostly on the hoods in cross and the long TT/ short stem combo makes me feel like I am driving the most power and in the best position for control of the bike. Getting down in a low aero position is rarely an issue in cross, and if I need to, I can get in the drops. 

I don't subscribe to the "ride a smaller bike than you do on the road" theory. Anyone have a good argument for this?


AA


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## Art853 (May 30, 2003)

My thought is the larger frame is a more upright position because of the longer head tube. Granted it depends on the stem and spacers you use from there.


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## flanman (Jul 7, 2006)

I think the OP has it nailed.

Longer TT, short stem means longer wheelbase. Much better for tracking through mud and difficult terrain. On steep downhills - my main weakness - you're not so far forward. Larger frame usually means higher headtube. Most road frames have way too much of a drop. 

Longer TT is the way to go.


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## HarrieH (Sep 6, 2007)

I think it's all nice in theory, but a lot of bullshit.
Shortening the toptube by 15mm and having a longer stem (or the other way 'round) doesn't have ANY influence. Yes, theoretically, but not really noticeable.

Other elements, like wheelbase, front distance (BB-front wheel axis), head tube length,
do not depend on framesize or TT length. There's quite some difference is you compare different brands or just models within a certain brand.
You also have to take the seat angle, head angle and fork rake into consideration.

Yes, compared with roadbikes, many people will benefit a shorter bike (= length TT + stem) and higher handlebars (spacers, headtube length, stem angle and position, angle of handlebars, position of "brifters").
However, this has nothing to do with the frame size. More important is the brand & type you choose. At the end, the position of pedals, saddle and handlebars have to be okay. Length of tubes is not relevant.


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## J-K (Nov 5, 2006)

Not relevant?

I had a Kona Major Jake frame that had a 53.5cm top tube. To sit in a reasonable way, I put on a 140mm stem. It did not track at all in deep sand or mud. I kept wiping out on deep sand descends, normally my strongpoint. Also, there was a risk of touching the front wheel with my shoes. The bike was so nervous, at times I oversteered into a corner, wiping out on the inside of it.

Now I have a Salsa Las Cruces with a 56.5cm top tube and a 100mm stem. My roadbike has a 56cm top tube with a 130mm stem. The Salsa tracks really well when it has to and I do not feel any disadvantages in tight corners. On the whole, it is much more stable and it allows me to use more of my power to forward motion, it seems.

Offcourse, that first frame obviously was too small for me, and there are differences in frame design, but it is an example of two cases on opposite ends. That said: I would not go to a bigger frame with an even shorter stem.


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## HarrieH (Sep 6, 2007)

Did you compare head angle and trail of the Kona and Salsa? This could have more influence than length TT + stem.

Same for seat angle: if it's steeper and set your saddle correct (more backwards), this also increases the TT length in a certain way.


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## Vegancx (Jan 22, 2004)

I run my road TT length (55.5 cm) and go 2 cm shorter on the stem (90 mm). 

Perfect. 

As far as shorter TT equalling more upright goes, that's going to be more a factor of headtube length (which will be better on a bike that fits you) than TT length.


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## pretender (Sep 18, 2007)

JoelM said:


> I've gone through a lot of riders setups posted here and elsewhere and it seems that many of those that bump down in frame size end up running a 10mm longer stem (often flipped up to positive rise) to compensate, while those who shoot for approximately the same size roadbike/crossbike shorten their stem slightly.


I'm pretty sure I agree with you. Cross bikes tend to have longer wheelbase than road bikes, and I think people "size down" their cross bikes because they are sizing the frame based solely on top tube and not on the seat tube. So they end up on a too-small frame and use too much seatpost, moving the butt up and away from the handlebars, requiring some sort of riser stem (Here is a case in point).

Effective top tube is only half the equation in determining cockpit length, seat tube being the other half, but I don't think people fully grok that.


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## PeanutButterBreath (Dec 4, 2005)

J-K said:


> Not relevant?
> 
> I had a Kona Major Jake frame that had a 53.5cm top tube. To sit in a reasonable way, I put on a 140mm stem. It did not track at all in deep sand or mud. I kept wiping out on deep sand descends, normally my strongpoint. Also, there was a risk of touching the front wheel with my shoes. The bike was so nervous, at times I oversteered into a corner, wiping out on the inside of it.
> 
> ...


Hmm, those two bikes have more than an inch difference in TT and 140mm is a pretty darn long stem. Maybe Kona is different, but it seems like even 60cm frames never come stock with more than a 120mm stem these days. Sizing down and lengthening the stem is one thing, but you can take it too far.


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## jerry_in_VT (Oct 13, 2006)

I measure my saddle to center handlebar and saddle to brake hood distance, diagonally (ie true distance) with an accurate tape measure.

I tend to prefer a low center of gravity (ie maybe long for my size) but I size up the road bike/cross bike for a 1 cm differential.

So my road bike is 1cm longer from nose of saddle to the two points above. Well, exactly 1cm to the split on the stem clamp/center of bar. Bit different/more at the hood.

I run both bikes as low as possible on headtube as that is how I feel comfortable. Also, I am long in the arm and short in the leg, I think, for my height.

I wish my cross bike was a bit lower. I run a neg -17 stem on it and no spacers. That said, i am of course more upright on the cross bike as a result of the way I/most people ride a cross bike. I ride 95% of the time on the hoods. I scrapped the extra brake lever setup a long time ago. On the road bike, I get into the drops alot more often.

I also run a 44 on the cross bike and a 42 on the road bike.

My bikes have the same TT length. The cross bike is alot taller, but of course it has a much much higher BB as well. However, my saddle to BB distance is less (bout a cm) on the cross rig.

Net effect is that I am on the same size bike, same TT, same stem, but am slightly more forward and upright on the cross bike because I ride 44's, and stay on the hoods. This moves me forward and up, and weights the front wheel, and gets me the "nose of the saddle" type of power that I find most useful in a cross race (sort of like in a TT).

I guess thats all I have to say about that. Point being, its about alot more the TT length!

Jerry


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## dyg2001 (Sep 23, 2004)

HarrieH said:


> I think it's all nice in theory, but a lot of bullshit.


I'm with HarrieH.
You can't reduce how a bike will handle to one or two frame dimensions. Generic advice like "buy a cross bike that is one size smaller than your road bike" is meaningless. Different production cross bikes with the same "size" have radically different geometries. 
TT length and wheelbase are not directly correlated. Two bikes can have the same TT length but different wheelbases due to different chainstay lengths.
Having a really long TT may affect your ability to put weight on your front wheel. But your front wheel position is also affected by head tube angle and fork rake.


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## kvn371 (Nov 4, 2005)

*Bullshit?*



HarrieH said:


> I think it's all nice in theory, but a lot of bullshit.QUOTE]
> 
> I think :idea: that a shorter stem makes steering a bit more twitchy, as the bars travel a shorter distance (think of an arc) when turning. I'm not sure if this jives with people in this thread feel about handling.


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## ZenNMotion (May 28, 2004)

*Love the One You're With!*

I've had a lot of fun buying Ebay CX frames, building them up with the same basic mix of parts and then riding/racing them for awhile. It wasn't really planned that way, but I've been through 9 different rigs over the last 5 years (my wife greets the UPS man with a shotgun at the door...) The bikes all were all varied from 53.5-57cm top tubes- a fairly wide range, but with different setups they all worked fine for me. It was fun, and I learned a lot about what I like, what makes fit and handling vary so much with just small differences- it's really tough to predict from just the numbers. I've had my road bikes dialed in, what feels good hasn't changed in 20+ years of racing, and I'm picky, I notice what's off. But I've only done cross for 6 seasons, and still experimenting. I've come to the conclusion that if the size is in the ballpark most people, myself included tend to love the one you're with. Don't stress it too much. Once you've had a few rides on one rig, you get used to it and adjust yourself to it- it feels good. And the numbers are only part of the story, material selection, wheels and tires, components, not to mention all the fine points that a builder or quality manufacturer put into frame building makes big differences- but in the end a cross race is short, hard and chaotic, you can successfully ride just about anything and not know much difference, at least until you become a more discerning, experienced Elite rider. 

A description of what I like might be a little useful to you since I'm probably close to your size, 5' 101/2", long legs (33" inseam pants), narrow shoulders (size 37 suit jacket), 150lbs, mostly mid-pack B/Masters level rider with a few lucky top 5 results so far- my fitness and age limit my experience and handling, which I think are better than average for the B's at this point. My road bikes are 56X56c-t, 73deg parallel, 120mm 0deg stem, 140mmHT, 0.5cm spacer, I ride deep drop bars, and am comfortable with a lower position than most.

FWIW, of all the CX bikes I've had, here the two faves that remain in the stable, one or the other is the pit bike, depending on the course/conditions- remember I'm mostly a Roadie, YMMV. You'd do very well with some close version of either of them, though they're really different.
1) the "monkey bike"- Custom lightweight EL/OS steel built by a garage builder who's no longer in the bike business, too bad, I'd love to find him and shake his hand I love this bike, I have no idea why I'm the third or fourth owner, but it was Ebay gold at $125. 55 TT, short 52.5 c-t ST, very steep 75deg (ish, hard to measure) ST and HT angles, 120mm HT with a nearly horizontal 1-2deg slope to the TT. I fit it out with a Winwood carbon fork with 47mm offset, and a 110mm stem, 6deg. rise, 1cm spacers including cable stop. Short oval straight 415mm chainstays with a slight bend to fit 35mm tire, but no larger. High BB drop at 60mm. Basically with very steep angles, high BB, low trail, short wheelbase this thing rides like a monkey- it takes an inside line on slow turns really well, and the back wheel sticks like glue on slick steep uphills- I enjoy riding while others are forced off by lack of traction. And with the high BB, off-camber hillsides are my favorite places to move up. But it wanders a bit on straight power sections, especially on hardpack or pavement, not bad but not my choice for longer rides or pavement. Its great as a racebike though, feels more nimble and lively than stable, my position is forward to stick the front wheel through turns but its also easy to move back to unweight through sand or over berms. 
2) The Waterford- I have no idea why someone would sell an expensive custom lugged frame built just for them but they did and I bought it cheap on Ebay with no other bidders. I even asked Waterford to contact the original owner to be sure it wasn't stolen. The fit is completely different than the other, and also "perfect". 56x56ct, shortish 100mm 6deg rise stem with no spacers (just cable stop), road bike geometry, 73deg parallel ST/HT, 140mm HT, 70mm BB drop, 425mm stays, matching steel fork 43mm offset. Compared with the monkey bike, this one is great for long all day rides on mixed terrain, and tracks better in wet soupy mud, and is really stable on power sections and fast straight bumpy downhills. It doesnt carve turns as crazy close as the monkey bike, tending to wander out some. And I have to be more careful not to catch a pedal on offcamber sections. But I love the bike and it's my choice for training, less technical fast courses, and mud soup. With my position further back, I feel less powerful, but more efficient compared with the steep angled monkey bike.
Both bikes feel weird if I've been exclusively on one or the other for awhile, so I try to use them both. I often switch bikes when I'm doing consecutive races, and of course it's always great to have a pit bike ready. If I had to choose one or the other (for racing, East Coast, dry early season, it eventually rains, but not like NW and I usually do 1-2 races with some snow) I'd probably pick the monkey bike- not as classy and drop-dead gorgeous as the Waterford, but it's a righteous battle scarred cross racing tool, at least until that skimpy EL/OS tubing decides to buckle! If I ever spring for a custom rig, that will be the model.


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## PeanutButterBreath (Dec 4, 2005)

I always assumed that the inspiration for the "size smaller" argument was based on they fact that CX bikes are ridden differently than road bikes. Terrain is more techincal, standover is more important, aero positioning is less important. A slightly smaller bike (not just frame) will be more flickable (for lack of a better term).


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## pxt0909 (Aug 4, 2007)

*e-richey... what'chu think?*

As someone who rides a 56 cm road bike but a 52cm Ridley, I'm interested in this thread - But as someone who's tinkering with a torch, I'm really interested in what someone who actually builds frames has to suggest about this topic. 

Short top tube + longer stem can get wacky, but I don't think making a comparison between a road bike and a cross bike is apples to apples- On the road bike you're more often in drops thinking about "smooth power" (especially if you're Levi) but on a cross bike with all hell breaking lose, you're on the hoods trying to rip it and grip it.

I've found with the stem even slightly long or low on my cross bike my back will quit after the 3rd lap - on the road bike, hours and hours can go by with out a second thought. 

I'd suggest riding both bikes, pick one that feels good and go with it. Forget what you think people will think about your setup - dig on your own satisfaction and style. When it comes down to it, the dude wearing cutoff jeans who's flowin' and kicking butt could care less about your top-tube length and what angle your stem decides to dangle.
PXT


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## pretender (Sep 18, 2007)

pxt0909 said:


> As someone who rides a 56 cm road bike but a 52cm Ridley, I'm interested in this thread - But as someone who's tinkering with a torch, I'm really interested in what someone who actually builds frames has to suggest about this topic.


I might be saying something you already know, but Ridleys are sized center-to-center. Their 52cm Crossbow is actually 56cm center-to-top:
http://www.ridley-bikes.com/2008/Geometry/Crossbow.pdf


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## atpjunkie (Mar 23, 2002)

*this is a good assessment*



kvn371 said:


> HarrieH said:
> 
> 
> > I think it's all nice in theory, but a lot of bullshit.QUOTE]
> ...


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## Lectron (May 29, 2005)

A shorter TT does _*not*_ necessarily give you a shorter wheelbase at all, but it
might very likely give you a longer trail, meaning it's actually _*more*_ stable 
(less nervous) than the one with the longer TT. That due to to the larger frame's 
(very often) steeper HTA.

And those are the facts


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