ITT: Wheelsize & why 650C makes sense for smaller bikes

Multi part series from Rodriguez on designing bikes for shorter riders.

Start: 650c vs 700c | Rodriguez Bike News

Excellent diagrams showing ‘fake’ (steep ST to shorten the “TT”) small bikes in part 7:
Wheel size Cliff Notes | Rodriguez Bike News

+1 for 650c frames. There just needs to be more support from the industry, sadly that doesn’t translate to profit.

Pointless to suggest a wheelsize that has fuck all in the way of tyre options and availability. 26" will readily work for most small size bikes and there’s enough data to show that there is negligible effect on performance and rolling ability. 26" means a whole bukkake of rims and tyres perfectly capable of doing the job. 650c is in no man’s land … don’t expect the industry to come around on this one.

Dum question, but how different in size is 26" to 650c?

It’s like 700c versus 27 inch. Different enough to make you life hard if you choose the latter.

Smidge more.
12mm from 26" to 650C, 8mm from 700C to 27".
There are a few options for ‘road’ tyres for 26" but not much in the way of a 23C size tyre.
This is the most likely option as many of the touring bike builders are offering 26" wheels on their smaller frames or across the board.

I switched my polo bike from 24" back to 26" because of the lack of tyre choice. Pretty much BMX tyres, cheap-arse MTB tyres or nothing. Managed to get some Marathon Plus’ in 24" from O/S - still to be released in AUS.

The only reason why I prefer 650c over 26" is that there seems to be more road/track oriented bicycles that have been made for 650c as opposed to 26". Granted bicycles haven’t been in my blood for long but I have seldom seen many road based 26" bicycles. Most of the junior bikes here (eg hillbrick) are based around 650c which I personally find do the job quite fine.

Case in point I have a damn short wife who has an inseam of 64cm, the only road bikes (non step thru/mixte) i’ve found that suit her are all 650c. If there are 26" versions out there i’d jump at them in a heartbeat, alas no dice.

As i said my knowledge is quite limited so I may be (most likely) missing out on a huge chunk info out there. :slight_smile:

^ Go custom, although expensive:

Yup, for road/track/fasty-fast 650C, for all else, 26" has a much better range from wider slick to full knobby, and tyres are available everywhere.

There are good road tyre options for 650C, Gatorskin, GP4000, Pro Race 3, Rubino Pro, Opex Corsa Evo CX… Not so much in the >25/28mm range though.

Yes, you can’t just walk into any shop and buy them, but I can’t get my beardo 650B tyres in any shop either.

with good cause. Then you might think we support your beardo ways.

Out of interest have you seen any Hillbricks running 24" wheels?
I know they used to do them and have seen some young kids on them at the local Velo.

And some Googling found a thread on 650C ladies cross bike. What tyre options would there be for that? Zero?

Brunswick Junior Clinic has 24" and 20" Hillbrick trackbikes with proportionally small stems/bars/cranks/saddles.


20" Hillbricks


24" Hillbricks

650c cross bike tyres O_O can’t say i’ve seen anything, though i have never looked that way. I’ve just bought road tyres (rubino pro) but a quick google says MTB Dugast? Weight Weenies • View topic - who makes 650c cyclocross tires

Re the hillbricks, at the last roller racing event at Brunswick there were some junior hill bricks but i’m not sure if they were 650c or 24". Someone else might be able to answer that one. edit blakey did :stuck_out_tongue:

And for this reason i think it’s best not to complicate things. I/You/We like 'em but most people don’t care or have the time to become an expert in sourcing or stocking stuff they can’t readily find in any shop. Tying in with the recent articles on wheel size, rolling, deflection etc (Bicycle Quarterly Summer 2011) and also knowing that geometry can be readily altered to make bikes ride very similarly irrespective of wheel size, I think sticking to 26" will be an easier sell.

The bike industry will sooner make lightweight, skinny 26" tyres than they will make fat, wider tyres in a 650c size. The foot soldiers in moving bike design to smaller wheels aren’t racers, most are regular peep’s just wanting a bike for fun or to commute on.

Are the 20" bikes running 451s like the junior BMX ?
So that means there are 451 ‘cross’ tyres already so we’re all set for junior cross?

And are they running BMX 110BCD cranks to get the really short arm length?
Looks like there is lots of cross over with junior BMX.

I haven’t exactly read this thread yet, but I thought I might add that as a short rider, I much prefer 650 over 700c. I actually do feel a bit slower (I’m guessing due to more rolling resistence with the small wheels), but it’s worth it for the comfort. Plus I can get bargains that will make you all jealous. And everyone always wants to try it and I like it when my friends look like they are on clown bikes.