650 vs. 650B

[kevin lindsey]

No doubt a dumb question, but here goes: is there a difference between
650 and 650B tubes? I just bought three sets of 650x18s for my
Bleriot, only to find that they look suspiciously thin for my 36mm
650Bs.
Anyone know where I can buy 650B tubes in northern Virginia?
Thanks,
Kevin

[Leslie]

There's 650A and also 650C in addition to 650B....

http://www.sheldonbrown.com/harris/tires/index.html


I would think a good LBS should have them, but if you don't know of one handy, Rivendell's got them and can send 'em your way...

[Tim McNamara]

There are 650A, 650B and 650C. Likely you have 650C tubes which are a smaller diameter as well as a smaller width than 650B.

http://www.sheldonbrown.com/26/index.html

Mos people mail order for this stuff since it is the rare LBS that stocks them. However, any bike shop with an account with QBP (which is most bike shops) can order them for you.

[Bill M.]

I think most of us just use 26" MTB tubes of the appropriate width.
Works fine for me.

Bill

[Horace]

The problem isn't with the "650" part of the sizing. If you stick 650x18 tubes into 650x36 tires, yes, the tubes will seem thin.

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[Horace]

650C and 650B are certainly close enough in diameter that you could use the same tube; but most 650C tires are narrow racing tires, so that's probably all the bike shop had. You probably want something like this:

http://www.rivbike.com/products/show/inner-tube-650b/10-066

But someone else also mentioned that you can use a 26" tube and that would be pretty close too.

[Philip Williamson]

The key number there is "x18," which would be half as wide as you
want. Upside... it's light. I've been putting 26" tubes in 650A tires
for years.

Philip

Philip Williamson
www.biketinker.com

On Jul 2, 6:55 pm, kevin lindsey <lindsey.ke...@gmail.com> wrote:

[Steve Palincsar]

On Sat, 2011-07-02 at 22:27 -0500, Tim McNamara wrote:
> There are 650A, 650B and 650C. Likely you have 650C tubes which are a
> smaller diameter as well as a smaller width than 650B.
>
> http://www.sheldonbrown.com/26/index.html
>
> Mos people mail order for this stuff since it is the rare LBS that
> stocks them. However, any bike shop with an account with QBP (which
> is most bike shops) can order them for you.

I doubt there's an LBS in the United States that doesn't have
26x1.25-1.5 or 26x1.5-1.75. That's the Mountain Bike 26" size. One of
those two widths will be right for 650B tires; it seems to depend on the
brand. Specialized 26x1.5-1.75 is so wide I've had trouble fitting the
tube under the tire bead, and their 1.25-1.5 is just right, but in the
Maxxis Ultralight the 1.5-1.75 fits perfectly.

[CycloFiend]

on 7/2/11 11:14 PM, Philip Williamson at philip.w...@gmail.com wrote:

> The key number there is "x18," which would be half as wide as you
> want. Upside... it's light. I've been putting 26" tubes in 650A tires
> for years.

I have found that running undersized tubes (i.e. the "second" number - in
this case the "18") seems to result in more pinch flats offroad. My working
theory is that the material is stretched so thin that it doesn't take much
to pierce it.

I've been going up one size, and as long as you aren't blowing the tire off
the rim, it seems to give another layer of protection. Works for CX, works
for trails.

- Jim "love them 45's in the 33 1/3's"

--
Jim Edgar
Cyclo...@earthlink.net

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it."
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[Michael Rivers]

Spokes in NoVA has Specialized 26 X 1.50/2.2 tubes which I have been using without difficulty with 650b tires from 32mm to 42mm wide.  They have both Presta and Schrader valve varieties.

Although the Schwalbe 650b tubes have that cool clear valve cap, I can't tell the difference between the brands.

Mike