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Yet another newbie question (regarding stem length)(12 posts)

Yet another newbie question (regarding stem length)empacher6seat
Apr 21, 2002 11:18 AM
After months of looking for a cheap road bike that wont fall apart as soon as I touch it, I've found one. The only problem is, it was custom built for someone with a small torso. I have a bit of a longer torse. I was wondering if it would be possible to compensate with a longer stem?
Some more information, please?Kerry
Apr 21, 2002 3:19 PM
Are you looking at putting a 14 cm stem on a 49 cm seat tube frame? Probably a bad idea. Without any information, it is impossible to answer this question except in the most general of terms: frames in the 49-50 cm range would typically have a 6-7 cm stem, 53-54 cm frame = 8-9 cm stem, 56-58 cm frame = 10-12 cm stem, 60-62 cm frame = 13-14 cm frame. Plus/minus a cm in stem length wouldn't have a big effect. Plus/minus 2 cm starts to throw the weight distribution off, though this will depend on a lot of factors.
Some more information, please?empacher6seat
Apr 21, 2002 4:21 PM
It's a 58cm frame... but has a 56.5cm top tube.
I was just wondering what the bounderies would be for stem length.
Some more information, please?atpjunkie
Apr 21, 2002 6:25 PM
You can take that stem to 130, maybe 140. Sounds like a crit bike or some other bike with "sprint geometry". The frame fits as far as standover I assume so set saddle height and saddle fore/aft first. Once you are fit to the crank and pedals you can determine "reach". When you are holding the bars in the drops your knees should just clear your elbows as a good starting point. Determine stem length by that. I'd say if a 130 is too short still, the TT is too short for your size.
Some more information, please?empacher6seat
Apr 21, 2002 9:17 PM
Ok, thanks for the help.
The bike was custom built for someone with a short upperbody. I think it has a pretty short stem on it, so... we'll see what can be done.
Some more information, please?atpjunkie
Apr 22, 2002 9:06 AM
Yes check it out. By your name I assume you are/were a rower. I rowed engine room back in college both Port and Starboard. Good luck on the stem, if it is a short one, lengthening will help.
Some more information, please?empacher6seat
Apr 22, 2002 9:21 AM
That's cool... there seems to be a lot of rowers/cyclists around... they're excellent cross training sports for eachother.
Some more information, please?atpjunkie
Apr 22, 2002 3:40 PM
I think they equal each other in masochistic tendencies.
I think I'm addicted to the endorphins after a good suffering.
Some more information, please?nickie77
May 3, 2002 1:01 AM
This formula comes from 3T.
Measure the vertical distance from your sternum to the pelvic bone. That is the B distance. Measure the distance from your shoulder joint to the wrist. That is the b distance. Now, get the ratio of B/b. For a 58 cm frame, the nominal stem length is 11.5cm. If the B/b ratio is equal to 1, then use 11.5cm. If B/b is less than 1, then use stem length of 10.5 to 11 cm. If B/b is greater than 1, then use stem length of 12 - 12.5 cm.
Hope that is clear enough.
Some more information, please?nickie77
May 3, 2002 1:04 AM
This formula comes from 3T.
Measure the vertical distance from your sternum to the pelvic bone. That is the B distance. Measure the distance from your shoulder joint to the wrist. That is the b distance. Now, get the ratio of B/b. For a 58 cm frame, the nominal stem length is 11.5cm. If the B/b ratio is equal to 1, then use 11.5cm. If B/b is less than 1, then use stem length of 10.5 to 11 cm. If B/b is greater than 1, then use stem length of 12 - 12.5 cm.
Hope that is clear enough.
Stem length relative to frame sizesimstress
Apr 22, 2002 9:16 AM
My 48cm bike came with a 10cm stem. Should I try a larger frame with a shorter stem? (I have generous standover on my current frame.) Wouldn't a 6cm stem be really twitchy?
Stem length relative to frame sizenickie77
May 3, 2002 1:03 AM
This formula comes from 3T.
Measure the vertical distance from your sternum to the pelvic bone. That is the B distance. Measure the distance from your shoulder joint to the wrist. That is the b distance. Now, get the ratio of B/b. For a 48 cm frame, the nominal stem length is 6.5cm. If the B/b ratio is equal to 1, then use 6.5cm. If B/b is less than 1, then use stem length of 5.5 to 6 cm. If B/b is greater than 1, then use stem length of 7 - 7.5 cm.
Hope that is clear enough.