All The Six Fifty Bees Thread! (650b, 27.5 etc.).

Question....

Currently in the process of beginning a custom frame for my girlfriend around 650b wheels (due to her height). We'll be wanting to run them with 28mm tyres rather than the traditional big volume stuff normally associated with 650b as she needs them to be smaller than 700c wheels or it negates the whole point of going 650b.

Does anyone have any recommendation for road based narrow 650b tyres for women's bike? Best I can find are 25c Schwalbe pro Ones.

Thanks

You've got Kojaks at and Conti Contact Speed both at around 32mm. They are quite heavy and stiff and only available wired.

I'd strongly advise designing the bike around 42mm tyres. You then have far greater choice of much better tyres. To all intents and purposes a 650b tyre rides like a narrower 700c tyre anyway on all but perfect surfaces.

If you really must have small outer diameter ... you'd probably be better with 650c and 25mm tyres?

The whole point of designing the bike around 650b is to decrease the size of the bike and get something much more in proportion for her height (5ft 3). It seems there's sod all tyre choices for women wanting small road bikes based on 650b tyres....

^ I added a line about 650c

650b with 42mm is smaller than 700c ... unless we're talking 23mm tyres.

Yeah I think we're going to have to settle for 25c

Next challenge is to find a fork where it won't look ridiculously gappy at the front

I would love a fast 32mm 650b road tyre. It's a sweatspot imho and almost any road frame becomes convertable.

You'd have better luck designing around a fast, mid size 26" tyre. More of them around

^ This

@Hulsroy, its SPG time!

schwalbe is basically it at the moment
one and pro one in 25mm
Durano DD in 28mm

My guess is that 650B will take over from 650c in small bikes, see canyon's small women's bikes

Trail calculation for 650b. If I reduced wheel diameter from ~686mm (700x33) to ~670mm (650bx42ish) am I right in thinking that trail is decreased proportionally, to 670/686 x previous trail? None of the angles change so all the triangles should be mathematically similar yes? I am just changing the height of the lower triangle in the diagram down there

i.e. for 65mm trail with 700c my new trail is 63.5mm?

Just use: http://yojimg.net/bike/web_tools/trailcalc.php

And so it's my turn for some idiot questions:

I would like to have a go with 650b on my commuter bike.
It's an SS rat bike (I believe is an old BLB trick frame with horiz dropouts) which I use for commuting.

I was thinking to swap the front fork with one with disc so I can install a Shutter PD-8 dynamo hub that is currently not in use.
However, the rear must be brake rim.

Based on these considerations, which will be the pair of rims that potentially looks similar?

Budget is under my feet.

So, I bought the Ventura rims, although they were black. Luckily, they were painted, not anodised, so few minutes and they became silver.
Now time for frame

1 Attachment

needs a build thread!

If I’m doing the ‘wrong’ way conversion, ie frame built for 26”, with 27.5” x 42mm tyres, hoping to squeeze a gb mudguard in too ... anyone know or is able to quickly add up what sort of axle to crown/ axle to bridges would be the minimum requirement?

Forget about brakes for now btw.

42mm 650b should be about the size of a 56,5mm 26" tire (about 12,5mm different rim size)

Cool, thanks for reassurance, I was working out 25mm increase in BSD, couldn’t really believe it is such a small difference to 26.

If you don't end up doing this, I'd maybe be interested in the SP hub

I will let you know, thanks.
Many variables are not matching...and few moneys are left ahha

Blue lug has built loads of 26"-27,5" conversions on Surly Disc Truckers.
From memory they mostly fit around 40-42mm tyres with mudguards.

okey thanks. The thing I’m thinking of is likely to have similar clearances if not bigger than Surlys.

Sounds interesting!

I may be talking rubbish, haven’t got my sweaty paws on the bike yet...

Any recommendations for a cheap pair of 650b wheelset, disc, deep profile but not carbon, with quick release and 135 mm rear, 100 mm front spacing, 32 holes?

Thanks