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correct stem length?(14 posts)

correct stem length?girodebirdman
Aug 21, 2001 11:55 PM
What is the general accepted stem length for a correct-fitting top tube? Is it between a 110-120, or does it matter much if you are riding a 100 or 130? The reason I am asking is because I can get an absolute killer deal on a frame that has a .8cm longer top tube than I am currently using, and would require me to drop down to a 100-105mm stem (from my current 110). Thanks!
Breezydz
Aug 22, 2001 4:39 AM
Shorter is probably less of an issue than longer for me. I'd be more concerned about my center of gravity than my stem length.
correct stem length?davidl
Aug 22, 2001 4:50 AM
I'm using an 80 on a 525 top tube frame and the bike feels good to me. I have short arms.
re: correct stem length?Johnn Evans
Aug 22, 2001 6:31 AM
Speaking of stems, is Salsa the only co that makes a threaded road stem that has some rise? They make one at 105deg, every thing else I've found is flat or drops.
Stems with risejtolleson
Aug 22, 2001 7:14 AM
Profile also makes them.
Stems with riseJohn Evans
Aug 22, 2001 7:34 AM
You wouldn't have a link to one of the on-line stores that carries them would you?
Stems with riseKevin M
Aug 22, 2001 7:58 AM
http://www.bikeusa.com/components/stems/stems3a.htm
ITM Big OnePaolo
Aug 22, 2001 11:54 AM
http://www.worldcycling.com

ITM BIG One with Rise
(10 degree rise)

or simply buy the ITM Big One or ITM Millenium in the size you want and turn it over - they are regularly 80 degrees - flipped over is a 10 degree rise. ITM BIG one also comes with 0 Degree rise. call them.
Correct fit mattersjagiger
Aug 22, 2001 6:56 AM
If you can be comfortable then it works. You can adjust the overall length by swapping out the stem for one thats shorter or longer. Keep in mind that following:
Correct fit = Top Tube length + Stem length + Comfort
If the bike fits ................Live Steam
Aug 22, 2001 8:50 AM
ride it. If it is only a matter of a few mm and everything else is OK, then no problem. Besides, you can make up different combos of stem lengths by varying the runout on the handlebars. Some bars have a shorter reach than others so you can go with a longer stem of say 110mm or even 120mm and use a shorter reach bar.
seat tube angles the same?C-40
Aug 22, 2001 8:59 AM
Remeber that you can't compare top tube lengths directly, unless the seat tube angles are also the same. One degree steeper seat tube angle effectively lengthens the top tube by about 1.2cm, depending on the frame size.

The formula to accurately calculate the effect of a seat tube angle is: saddle height(cosA -cosB). As an example, for a saddle height of 75cm (measusured along the seat tube to the center of the BB) and angles of 73 and 74 degrees, the difference is 1.26cm.
That's a handy formula to have :-)Live Steam
Aug 22, 2001 9:05 AM
It is great for setting up different bikes so that minimul dialing in is required. Thanks!
seat tube angles the same?girodebirdman
Aug 22, 2001 9:11 AM
Yes, the seat tube angles are the same. It is the same make of bike, but a 1cm larger size than I am currently riding. I probably won't have the pleasure of riding the frame before I buy it, as it is frame only, and unbuilt, meaning I will have to spend a few hours swapping parts. I know that my current model fits, but I have so much seatpost sticking out (about 165mm) that I figured the size larger would fit as well. My only sticking point was the top tube, as I have fairly short arms for my leg length. If I won't notice adverse handling effects with a shorter (100mm stem) then I will probably go ahead and purchase it. It seems logical that a bike with a 1cm shorter stem would be affected in handling, but is this what happens in actual practice, all factors being equal?
no problem with a 100mm stem...C-40
Aug 22, 2001 1:52 PM
It does sound like you have more seatpost showing than necessary. I only have about 180mm from the top of the top tube to the top of the saddle on my C-40. The larger frame will also give you a longer head tube require less head tube spacer.

Whatever stem length you happen to need, you'll quickly get used to any minor difference in steering quickness.

I rode my C-40 for 2000 miles with a 120 stem, but finally concluded that it was longer than needed. I switched to a 110 and never noticed any difference in the steering. The 110 still gave me ample knee to elbow clearance when riding in the drops.