650b, 27.5 ??

steve_sordy

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#3
650b describes the rim
27.5 is the "nominal" diameter in inches of the mtb tyre fitted on a 650b rim.

650b is very precise. 27.5" not so much. I suspect that it was used because it was half way between the once very popular 26" and the new pretender the 29" wheel/tyre combo. In fact it wasn't even 27.5" it was nearly always less. Well it was when the tyres were 2.2" and on narrow rims (say up to 23mm). Now we have 30-40mm wide rims and 2.8" tyres, we are probably over 27.5 by now. :unsure:

Example: A mate of mine had a 26er and with the same brand/size tyres as me. He bought a new 27.5" bike. I asked him if he could tell it had bigger wheels. He said not, so I measured his wheel dia and got 27.25". I measured mine and got 26.75". He had Nobby Nics 27.5 x2.25" and I had Conti Trail Kings 26x2.2". But my TKs were BIG, his NNs were small. :)
 
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Zimmerframe

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#4
Isn't 650b the metric "euro" size and 27.5 is the imperial equivalent ?

and for some reason, in the world of bikes, a mix of imperial and metric is normal ?

Though you can't pay in shillings .. certainly not for an e-bike ..
 
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#7
I mean for all intended purposes it’s the same thing for us consumers. If you want to get technical about the definition sure. But if you’re going to go into a ship and ask for a mountain bike 650b or 27.5 tire, they are going to hand you the same thing.
 

B1rdie

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#8
I mean for all intended purposes it’s the same thing for us consumers. If you want to get technical about the definition sure. But if you’re going to go into a ship and ask for a mountain bike 650b or 27.5 tire, they are going to hand you the same thing.
Just kidding, mate 👍
 

steve_sordy

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#9
I mean for all intended purposes it’s the same thing for us consumers. If you want to get technical about the definition sure. But if you’re going to go into a ship and ask for a mountain bike 650b or 27.5 tire, they are going to hand you the same thing.
Only because they know what you mean. :)
When 650b/27.5 first came out, bike journalists used to refer to 650b because they were trying to (not so subtly) object to the use of 27.5 by the marketing guys.
 

Gary

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#10
There are a hell of a lot of words typed on this thread considering all the guessing and just making shit up going on.

650b has been around for decades in the road world. Just as 700c has.
Mtb marketeers nabbed each of these size, slapped on new sizes in inches to sell new tyres/frames/forks with wondrous new properties.

#Profit.

#Becauseyoureworthit
 
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miPbiP

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#11
27.5 is a pretence - that's 1/2 way between 26" and 29".

650b isn't, it's closer to 26" than 29".
 

R120

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#12
I always thought 650B was the wheel size, and 27.5 the tyre
 

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