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Help: Stem-clamp/handlebar mismatch.(5 posts)

Help: Stem-clamp/handlebar mismatch.gemcity
Jun 25, 2002 8:45 AM
I want to upgrade the OEM bars on my Bianchi Volpe (to Ritchey Biomax). I am happy with the current stem. I bought the bars and the bar diameter is slightly larger than my clamp. Bummer!

My questions...
(1) Apparently there is no single standard. What are the common sizes?
(2) Can't find a spec for my stem. I can get my size by measuring the OEM bar with calipers, right?
(3) The fit is close. I assume it is NOT OK to just clamp a bar into a slightly smaller stem. Right?
(4) Could I take the stem to a local machinist and have him round-out the stem to fit the new bar. Or, will that never be precise enough? I suspect this is a bad idea.

If it was my bike, I'd just buy a stem that matches.the dad
Jun 25, 2002 11:45 AM
That's way cheaper than an Emergency Room visit. The front of a bike is no place to take chances.
close doesn't count...C-40
Jun 26, 2002 12:59 PM
All handlebars are "close" to the same diameter. MTB bars and cheap japanese bars are 25.4mm (1 inch). Most all other road bars are 25.8 or 26.0 diameter. Ritchey bars are 25.8mm.

If you measure with a micrometer or dial calipers, you will find that bars are only close to one of these sizes and they are not all that round. The diameter will vary depending on where it is measured.

If your stem is an open-face type, with a removable faceplate, the 25.8 and 26.0 bars can both be used with stems of either diameter.

If the stem is an older style closed model (with one clamp bolt) the 25.8mm Ritchey bars should work, unless you have a cheap 25.4mm stem. If you have this odd diameter, I would get a new open-face stem of the proper 25.8mm diameter.
Thanks. I'm getting a stem...gemcity
Jun 26, 2002 2:44 PM
Apparently I have a cheap 2-bolt 25.4 stem. The only way to upgrade the bars is to get a new stem (I'm not real happy about that). Too bad close doesn't count! On the up-side I will have a sweet new stem with a refined bar-position too.

My LBS is hooking me up with a Salsa 1-bolt 26.0 stem AT COST to get my problem resolved (the bike and the new bars both came from them). You don't get that kind of service mail-order!

Thanks for the help!
Actually,Spoke Wrench
Jun 26, 2002 2:45 PM
My QBP catalogue lists Ritchie Biomax bars as having a 26.0mm clamp diameter. Scrunching your brand new bar into a smaller diameter stem, even if it is open face, doesn't strike me as being very cool. I'd pony up for a new stem. The majority of decent quality aftermarket stems will have 26.0 clamp diameter.

You can almost never replace just one part on a bicycle.