650b conversion - issues

[weisan]

Yes, even before the dust settled with the "crimping" saga, I have opened up yet another case of unsolved mystery.

So, assuming I want to put a 650b wheel on my Merlin Ti cyclocross bike, how do you solve the problem with the canti brakes being too high and not align with the rim brake track?

Please see picture.

[thirdgenbird]

I'm not sure you do. Disc and caliper are easy to convert. Canti is not. Even going from 27in to 700c can pose an issue with canti brakes.

[happycampyer]

Have disc tabs installed? I think it's easier with calipers since you can go from short reach to medium or long reach. Not sure if there is a canti solution.

[bicycletricycle]

Not much to be done about that unless you got a grinder, TIG welder and some argon.

Also, how would you solve your lower bottom bracket height? I guess it might be okay if it is a little high now.

[weisan]

I guess the consensus is..."no go". Thought I might check anyway. According to this chap, it's definitely no go.

"However, bikes that have cantilever brakes are not viable candidates for 650B conversion due to the fixed placement of the canti bosses. The bosses will be right next to the 650B rim and proper brake adjustment is not possible without relocating these brazed-on fittings."

https://www.bikeman.com/bikeman-blog...sion-guidlines

[pinkshogun]

i recently saw a doo-hickey that mounts onto the canti stud post that will drop the caliper enough to line up the brake pad with the rim

i dont remember who makes it or where i saw it but perhaps a google search or a looksy on the bob list or 650b list will help

[weisan]

there's always a solution...well, alright not always, but if only we don't give up so easily or come to a conclusion so quickly...

Elevn Brake Adaptors
http://www.maximumbmx.com/catalog.php?item=1205


V brake Post extender
https://www.danscomp.com/products-PA..._Extender.html

[marciero]

Not to be annoying, but, speaking of crimping, I would attach the rack at the axle rather than where you have it. You can make a piece for it or use the one you have there, oriented vertically. The setup as shown supports weight by acting as a lever on the stay and has the potential to concentrate the load, esp over bumps, at small point, magnified by the lever action.

[weisan]

Originally Posted by marciero

Not to be annoying, but, speaking of crimping, I would attach the rack at the axle rather than where you have it. You can make a piece for it or use the one you have there, oriented vertically. The setup as shown supports weight by acting as a lever on the stay and has the potential to concentrate the load, esp over bumps, at small point, magnified by the lever action.

marci pal, good eye! and good advice...I will take it!

[hokoman]

Originally Posted by marciero

Not to be annoying, but, speaking of crimping, I would attach the rack at the axle rather than where you have it. You can make a piece for it or use the one you have there, oriented vertically. The setup as shown supports weight by acting as a lever on the stay and has the potential to concentrate the load, esp over bumps, at small point, magnified by the lever action.

Could be an optical illusion from the flash, but the seatstay looks bent where you have the rack...

[weisan]

Originally Posted by hokoman

Could be an optical illusion from the flash, but the seatstay looks bent where you have the rack...

No illusion, it is bent...by design

[happycampyer]

Originally Posted by weisan

there's always a solution...well, alright not always, but if only we don't give up so easily or come to a conclusion so quickly...

It's an inexpensive experiment. Depending on the roads you intend to ride (especially how long/steep the dirt/gravel escents are), it may be fine. Bear in mind that these extenders would likely add some flex, which isn't a great thing to add to cantis/v-brakes.

[weisan]

Originally Posted by happycampyer

It's an inexpensive experiment.

you mean compared to crimping the chainstay?

thanks campyer pal.

[oldpotatoe]

Originally Posted by weisan

you mean compared to crimping the chainstay?

thanks campyer pal.

But if ya get them from Dan's Comp, they'll probably only send you one

[palincss]

Originally Posted by bicycletricycle

Not much to be done about that unless you got a grinder, TIG welder and some argon.

Also, how would you solve your lower bottom bracket height? I guess it might be okay if it is a little high now.

Usually lower bottom bracket height isn't an issue because the outside diameter of a 650B wheel with 38-42mm tire mounted is within a mm or two of that of a 700Cx23 wheel with tire mounted. However, it is a factor that should be borne in mind (along with whether the bike is equipped with cantilever brakes!) when evaluating a frame as a candidate for 650B conversion.