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A simple question(3 posts)

A simple questionScot_Gore
Nov 4, 2001 8:36 PM
I'm back on a road bike for the first time in 10+ years and THINGS HAVE CHANGED.

I got my first flat today, but I'm a good boy scout, I'm Prepared, or so I thought.

My tire says (in great big letters) 700-23c on the outside. So I purchased (months ago) replacement tubes that say 700x23-25c and 34mm presta valve on the outside of the box. They had the longest presta valve at my local REI so I figured this must be the right size for these new fangled wheels. (Shimano WH-R535's) So today, I pop the tire off the rim, pull my flat tube out and it says (in great big letters) on the outside 700x20/28c. I line up the presta valves on the replacement tube and flat and it's way short. (After the long walk home) I measure the presta valve on the flat, it's 50mm, long. Off to REI again. No tubes in the 700x20 range and no 50mm presta valves in any size. Of course it's November in Minnesota, so stock may be low. I pop out to the internet bike e-tailers and get more confused. Is it extra long presta I'm after? 700-23 or 700-20? Previous experience told me to read the side of the tire and match up. Thought I knew what I was doing...Ahhh Hubris.

Can the forum give me a quick education on rim, tire, and tube matching.

Thanks in advance.

700x20 or 700x23 will workspookyload
Nov 4, 2001 9:41 PM
Sorry about the tough luck on the road. That hasn't changed in ten years. Look for tubes that have valve stems of 48mm or 60mm. They are pretty common from most online retailers. Using 60mm will give you just a little more room to get the pump/cartrige on. You might want to find a valve extender for emergencies. It threads on to your shorter valve for inflation. They can leak pretty bad if teflon tape(plumbers tape) isn't used. I keep one in my bag in case I have real bad luck and have to get a third tube from a stranger and it isn't extended valved.
Your tire size was right, btwjtolleson
Nov 5, 2001 7:44 AM
It was just the stem length that got you.

That 700 X 20/28, for example, will fit anything from 20 - 28 (including, obviously your 23s). That's a pretty common range for tubes.