Bicycle Mechanics - Stem/extension and headset

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wjcronin2002
11-22-03, 05:48 AM
I'm a roadie who is pretty tall. My seat is much higher then my handlebars. While I"ve gotten used to this, I'm sure I'd be much more comfortable if I could get those handlebars higher. I see that I can get different stems with longer extensions. Two questions - How do I know if a particular model is compatible with my headset, and two, can you just by the extension? Thanks for any advice.

uciflylow
11-22-03, 06:54 AM
Get a Delta Ahead Stem Riser, if you have 1 1/8 threadless and just want to move the bars higher. Works great. :D
John E
11-22-03, 11:06 AM
Since late-model steerer tubes use ISO-diameter stems, all you probably need to worry about is threaded-versus-threadless. In the good old days, the French and the Swiss used 22.0mm stems, whereas the rest of Europe used 7/8" = 22.23mm.

shokhead
11-23-03, 02:22 PM
degree of rise will bring them higher.
Gonzo Bob
11-24-03, 06:55 AM
1-1/8" steer tubes need a 1-1/8" stem. 1" steer tubes can use either a 1" stem, or a 1-1/8" stem with a shim.

You also need a stem with close to the same stack height. If you get one that's a lot shorter, you may have to trim more off the steer tube or insert some spacers. If you get one that a lot taller, you my not be able to screw in the top cap. There's usually not a lot of variance in stack height but it could be an issue in the extreme case.

There are two bar clamp diameters - 25.8-26.0mm and 31.7mm.

Many threadless stems are flippable. So if you get one with 6 degree drop, it can be flipped to give the bars 6 degree rise. +- 10 degrees and +-17 degrees are other common stem angles.
shokhead
11-24-03, 08:22 AM
1-1/8" steer tubes need a 1-1/8" stem. 1" steer tubes can use either a 1" stem, or a 1-1/8" stem with a shim.

You also need a stem with close to the same stack height. If you get one that's a lot shorter, you may have to trim more off the steer tube or insert some spacers. If you get one that a lot taller, you my not be able to screw in the top cap. There's usually not a lot of variance in stack height but it could be an issue in the extreme case.

There are two bar clamp diameters - 25.8-26.0mm and 31.7mm.

Many threadless stems are flippable. So if you get one with 6 degree drop, it can be flipped to give the bars 6 degree rise. +- 10 degrees and +-17 degrees are other common stem angles.
80/100 is more common and its 31.8,not 7.Deda uses 31.7