27,1/2 or 650b gravel wheel

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rjb
Posts: 7200
Joined: 11 Jan 2007, 10:25am
Location: Somerset (originally 60/70's Plymouth)

27,1/2 or 650b gravel wheel

Post by rjb »

Are these the same size.? I've a new rear wheel from a Carrera bike, wide rim 36mm internal. Not sure if it's 650b or 27,1/2. No size marking on it that I could find. Perhaps it's under the wide rim tape. Could even be tubeless but having never come across one I not sure. What's the difference?
It's of no use to me so will put it in the sale section soon.
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
PH
Posts: 13106
Joined: 21 Jan 2007, 12:31am
Location: Derby
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Re: 27,1/2 or 650b gravel wheel

Post by PH »

Yes, it's the same.
mattsccm
Posts: 5101
Joined: 28 Nov 2009, 9:44pm

Re: 27,1/2 or 650b gravel wheel

Post by mattsccm »

Being super picky some might say that something flogged as 650b is a nice French road wheel that has a certain charm and takes nice wide tyres whereas 27.5 is a nasty modern MTB size that is either the new thing or obselete already. Possibly something sold as the later may have a wider internal width or maybe it won't . It won't be for sale in silver though.
Either way, on the whole the only thing you worry about is the width. A little bit and thats all.
JohnR
Posts: 248
Joined: 6 Jul 2020, 3:51pm

Re: 27,1/2 or 650b gravel wheel

Post by JohnR »

Here's a typical tubeless rim:
https://www.spacycles.co.uk/smsimg/195/ ... -2-195.jpg
The distinctive feature is the flat (or even sloping outwards) shoulders to the central depression. This helps the tyre beads move outwards and lock into place.
Usually riding a Rohloff-equipped Spa Cycles Elan Ti
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