650b

[MikeW]

I've been thinking of getting a set of 650b wheels but not sure if the bike will take them. Is there an easy way to work it out? It's a genesis cda10. I can't find any info anywhere about if they will fit or not.

[ScotRoutes]

It'll definitely take 650B wheels, though tyre width might need a bit of experimentation and the smaller wheels will lower the BB (and CoG) a little too.

[Bearbonesnorm]

Aye, as Colin says, it's not the wheels but the tyres. I like wider tyres on 650b rims in things designed for 700c (generally) but if you can't fit wide tyres, the point is largely lost and will likely result in something horrible to ride.

[MikeW]

Thanks for the help!

[Scattamah]

A bit of necrothreading here...

650b on a Flyxxi 29er....should be able to get 2.4" in the frame with a smaller wheel. Pros? Cons? A question for the more enlightened users here abouts.

Greetz

S.

[Bearbonesnorm]

If there's not masses of clearance available, then I'll always (well, nearly always) take a high volume 650b above a narrower 700c. Once clearance reaches proper 29" mountain bike widths, let's say above 2.2", things change and the benefits deminish somewhat.

[jameso]

Uh oh, here we go... At one point I did wonder if there was a rule of thumb for where more volume makes up for less OD and v-v, in terms of general XC rolling ability.

If you take volume/casing size and wheel OD to be the 2 variables,

I found a 700 x 45 Riddler (actual casing volume closer to a true 40-42mm) 710-715mm OD, and a 650 x 50 G-one 685-690mm OD to ride very similarly.
Also a 700 x 60 Ardent 2.4 750mm OD, and a 650 x 72 Trailblazer 725mm OD, they were balanced in pros+cons and roll-over was really similar - on average/this is not science etc.

= in both cases, the 700C wheel had a casing size X wheel OD number that was ~87% of the 650B wheel.

So it seems that a slimmer tyre on a bigger rim (assuming going from 650B to 700C) has 'in general' similar roll-over ability as a bigger tyre on a smaller rim when the casing size X OD (both in mm) result gets to 85-90% of the result of the bigger tyre on smaller rim.



Of course the bigger tyre handles the impacts better. If the weight is the same they will feel as fast/slow as each other (OD makes no odds there). The narrower tyre with larger wheel OD will feel different to handle, steers more 'accurately' or has an edge-to-edge feel more than a 'boat roll'. But on a mix of road/easy tracks, woodland trails and simple singletrack there's not a lot in it at this 85-90% point*

*until you load the bike up - then I think more volume has different gains/losses.

[Bearbonesnorm]

Don't go getting your tape measure out on me. This is the internet, he requires conjecture not measurements

[jameso]

Conjecture quantified by bad science and objectives applied to measure subjectives, it's perfect. It worked better than looking at the actual air volume of the tyre inc PSI, that was a dead end

(And those tyre casing size are from memory anyway .. so it's really sh1t science. Still, the numbers work out over that general range)

[Al]

Scott - you not finished building it yet
When I had it I had a 29er 2.4 Hans dampf on a Stans flow rim that came up pretty big and fitted fine if that helps your calculations.

[Scattamah]

@Al - she's built...and named. Takes the wheels (29") from Lois ok...rides ok. Creak from the bottom bracket under load...but that's probably torque on the BB. Hoping it's not the BB unwelding from the carbon. I do have a q about the internal routing though...I'll PM you about it fella.

@Stu 'n James...ta for that. Sounds like I'll be ok. I was talkin' with MaM earlier and he mentioned lower BB/CoG...but that I should be ok with. Hell...anything with a lower CoG I might be able to stay upright on after drinks.

FWIW....bad science and conjecture are fine...you could even bullsh!t right about now...Leffe is good for that.

Ta y'all.

Greetz

S.