700 to 650b ?
mr_eddy
Posts: 830
I have a new Holdsworth Elan (Disc equipped steel road bike).
I have recently stuck on a set of 32c Conti Sport Contact 2 tyres and the ability to take in some off road paths has been great fun to the point where I have now switched from 50-70 mile road rides at the weekend to 30-40 mile off road bashing. Just did a big session around Derwent Water in the peaks with 70% of it on fire roads and single track.
With the above in mind is there any reason why I can't swap out the 700c wheels and tyres for 650b?
PX don't recommend it but that is only because they want to sell me their dedicated gravel bike.
I have seen pics of the same frame (albeit a different fork) running 650b with what looks like 42c tyres and also a dude with a Stelvio (similar frame) running 650b with stock fork and again pretty big tyres.
As it stands with the 700x32c tyres the closest the tyres get to the frame is actually not to do with the width the rear tyre is about 3mm from touching the seat tube but it has about 5mm of clearance to the chainstays and the front again 5mm clearance to the sides of the fork but about 4mm to the fork crown at the top.
Looking at Bike Calc a 700c wheel with 32c tyre has a circumference of 2155mm, A 650b x 2" tyre is 2153mm so on that basis the only limiting factor is the tyre width and getting it to fit within my frame. I reckon I could get a 650 x 42mm in at a push or a 40mm
I could get an extra set of rotors and a cassette and have the 700c for the commute and the 650b for the weekend
Does this add up ?
Any reason why it won't work ? I am running discs so no need to worry about brake drop etc.
Would swapping out to 650b x 42mm be a big improvement in terms of comfort and grip over a 700 x 32mm ?
I have recently stuck on a set of 32c Conti Sport Contact 2 tyres and the ability to take in some off road paths has been great fun to the point where I have now switched from 50-70 mile road rides at the weekend to 30-40 mile off road bashing. Just did a big session around Derwent Water in the peaks with 70% of it on fire roads and single track.
With the above in mind is there any reason why I can't swap out the 700c wheels and tyres for 650b?
PX don't recommend it but that is only because they want to sell me their dedicated gravel bike.
I have seen pics of the same frame (albeit a different fork) running 650b with what looks like 42c tyres and also a dude with a Stelvio (similar frame) running 650b with stock fork and again pretty big tyres.
As it stands with the 700x32c tyres the closest the tyres get to the frame is actually not to do with the width the rear tyre is about 3mm from touching the seat tube but it has about 5mm of clearance to the chainstays and the front again 5mm clearance to the sides of the fork but about 4mm to the fork crown at the top.
Looking at Bike Calc a 700c wheel with 32c tyre has a circumference of 2155mm, A 650b x 2" tyre is 2153mm so on that basis the only limiting factor is the tyre width and getting it to fit within my frame. I reckon I could get a 650 x 42mm in at a push or a 40mm
I could get an extra set of rotors and a cassette and have the 700c for the commute and the 650b for the weekend
Does this add up ?
Any reason why it won't work ? I am running discs so no need to worry about brake drop etc.
Would swapping out to 650b x 42mm be a big improvement in terms of comfort and grip over a 700 x 32mm ?
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Comments
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I've just got a cannondale slate which comes with 650b, 42mm tyres.
I've seen people stick 700s on with road gearing and switch between so think this is doable as long as you have the clearances.
The 650b tyres I have are almost identical to 700c in terms of circumference due to the gigantic air volume in them, and they are really smooth to ride on.0 -
I have actually managed to shoe in some 700c x 38c. I never attempted before because I thought "there is no way they are fitting in" but after completing a 1 x setup last night the extra space near the seat tube meant I managed to get them in. Clearance at the back is a bit tight with about 3mm around the seat stay bridge so maybe an issue in muddy conditions but I will see this weekend.
Took it to work this morning the 1 x 9 works a treat and whilst 34x11t is not the highest of gears with the 38's I can run 20-25mph at reasonable cadence (90-100). Not dropped a chain but I did take a few more links out to keep the chain tight.
Time will tell if any further adjustments are needed maybe a chain keeper or narrow/wide ring but unless I get lots of drops this weekend I won't bother.
Will post pic of the new mongrel!0
