700c wheels on the B2- Well that was entirely inconclusive

[ElyDave]

Added a pair of disc braked 700C wheels to the ICE B2 upgrading from the 26" that came with it. Shod with 25mm conti 4 seasons, so not slow tyres either, assumption being that as long a I can keep turning the pedals I should be going quicker for the same cadence.

At lunchtime rode the almost identical lap to wot I rode in August with the 26" on it.

August - 27.62km / 1hr 2min / average 26.6kmh / Ave HR 117, Max 136

Today - 26.54km / 59:51 / average 26.6 / ave HR 135 / max 153

Only real conclusion there is that I can't really make a conclusion.  Although it was breezy in August, I think it was somewhat more so today, suggesting that the 700Cs will have expected advantage in stiller weather and that I might have been even slower on the 26" today.

Surprisingly no adverse control/getting feet to ground issues, may even try clipless next time. 

[Torslanda]

I was told once but I've yet to prove empirically that a 559 wheel with a 50mm tyre is the same rolling radius as a 622 with a 23mm.

As I've never owned a frame that would take both sizes it never occurred to me to try...

[Mr Larrington]

Bike tyre sidewalls are usually as near as makes no odds the same height as the tyre is wide so a 50=559 would give a diameter of ~659 mm and a 23-622 ~648 mm.

[ElyDave]

Bike tyre sidewalls are usually as near as makes no odds the same height as the tyre is wide so a 50=559 would give a diameter of ~659 mm and a 23-622 ~648 mm.

The 559s had a 28mm Gatorskin on them so that gives 559+2*28 = 615mm

622s had 25mm GP4 seasons giving 672mm

so getting on for 150mm difference per revolution

[tom_e]

I did the same conversion on mine - convinced myself it felt slightly faster afterwards.  But I wasn't comparing like with like, I was switching to a lighter 700 wheel with a narrower tyre from a slightly wider, heavier 26" wheel and tyre.  I also thought the bike looked better with the new wheels...

And yes, the difference in height was small enough it never bothered me particularly either.  Still doesn't on a similar arrangement of two wheelsets on an upright bike, though I can tell the difference more there because it's harder to reach the ground from higher up.

[Torslanda]

I was told once but I've yet to prove empirically that a 559 wheel with a 50mm tyre is the same rolling radius as a 622 with a 23mm.

As I've never owned a frame that would take both sizes it never occurred to me to try...

 . . . but when I did the comparison it proved to be utter bolleaux

[tom_e]

I was told once but I've yet to prove empirically that a 559 wheel with a 50mm tyre is the same rolling radius as a 622 with a 23mm.

As I've never owned a frame that would take both sizes it never occurred to me to try...

 . . . but when I did the comparison it proved to be utter bolleaux

Bit harsh.  If you go by schwalbe's figures then a 23-622 is more of a match for a 60-559.  I agree, the common sizes don't really overlap, but a 50-559 is still closer to 23-622 than either are to a bigger touring size like 42-622.

Vested interest - speaking as someone who does have a [upright] frame which fits two wheelsets, one 700c, one 26".  I currently have 28-622 and 50-559 on them.  I do notice the difference, but it doesn't bother me.  I quite like that the 'heavy touring wheels' put my feet on the ground more easily.  Which wouldn't be the case if I had two wheelsets of the same nominal diameter, it would be the opposite by a similar margin.