[purple puma]

I realize if a top tube is not the perfect length, the stem length can be changed to get the correct reach. So, is there a point when the stem length is considered to short for a certain size frame?

The reason that I am asking is because the 62cm frame I am considering has the right top tube hight for me, but the TT length is a little too long and I would have the use a 11 or 10 cm stem. The bike shop fitter recommends that I go with a smaller frame (60cm, 59 cm TT) so I can use a 12 stem, which he says with match the frame size better. However I am concerned that on the 60 cm frame, I will not be able to set the handle bars higher in the future if I want to.

Is there any major disadvantage in using a stem length on a large frame that would normally be used on a smaller frame?

I plan on using my new cross bike for commuting a light touring.

Thanks!

 

[atpjunkie]

I ride 61 x 59 Road Bikes with 130 stems (neg rise). On my cross bikes I ride 58x59 cx bike with a 110 and a 58x58.3 with a 120) with a positive rise.
If you plan on touring and using panniers you may need to take this into account as shorter stems make bike twitchier in general. It's great for cx racing and tight hairpins but could be scary on a long, fast, heavily loaded downhill. I'm no expert in touring set ups but as far as general cx set up, for racing most guys I know use shorter stems.

 

[PsyDoc]

Yes...and no

The information about a shorter stem leading to "twitchiness" is correct, but you are looking at stems < 10cm to see a noticeable difference, in my opinion anyway. If I recall correctly, correct toptube length has something to do with the weight distribution on the bike where you typically want 55-60% of your weight on the rear wheel and 40-45% on the front. I see absolutely nothing wrong with running a 10 or 11cm stem on a bike. I do think your concern about handlebar height is a legitimate one and being comfortable on a bike is paramount. If you are not comfortable on the bike, then you will not ride it as much or as far. Given that you are not going to be racing (and I am not convinced it would matter if you were), I would suggest going with the 62cm frame and the 10 or 11cm stem so you will be more comfortable. I ride a 57cm frame and have an 11cm stem on it because I am more flexible now. But, I used to ride the same size frame with a 10cm stem and did not notice any difference in the handling characteristics of the bike.

 

[Dan Cas]

look at the front center...

The head angle affects this distance from the BB to the front axle and determines where your weight will be in relation to the front axle.Cross geometry is all over the place and you need to compare this distance to your road bike to draw a meaningful conclusion.

A 10 or 11 stem is fine tho.

Dan

 

[PsyDoc]

There is a...

...range of cross geometry, but I think the majority of bikes have a seat angle of around 73 degrees and a head tube angle in the 72 degree range. For example, the cross bike I just bought has a 72 degree headtube angle with a 56.5 TT length. The seat tube degree is similar (within .5 degrees) to my roadbike. Because of the slacker headtube angle, the length of the TT is shortened a bit...a little less than a 1cm. Dan is correct that you need to take the angles into account. Why not take some measurements from your roadbike (tip of seat to center of stem, saddle height, and your K.O.P.S.) and then have the shop set up the bike you are interested in with the same measurements and see how it feels.

 

[dreww]

Psydoc is right weight distribution is vital in cross for traction and power transfer and also overall comfort for all disciplines, but lets not forget even though geometry is similar to road the wheel base on CX is at least 1" longer (my CX is 3.4cm longer) while some of this is taken up by fork rake/slacker HT angle, majority is in the rear triangle for mud/tire clearance. You must sit further back to compensate for this therefore usually requiring a shorter stem and or shorter top tube. Common belief that you must have bars closer and higher on CX for better "control". Well I like control on my road bike too so I find a position that gives me good: visibility, muscle distribution (not too much weight on hands/arms etc), aero effects, adequate breathing room (no Ullrich TT position) and lastly control - not in specific order. Then shorten and raise stem by 1cm. Thats it, my saddle to stem drop is still 5" but I rarely ride in the drops if ever, mostly on tops or lever hoods.
Thats my opinion anyway.