glopez

i found a nice cyclocross bike on ebay and was wondering if i could change the wheels to 26" if i ever had to change or replace them.
would there be a problem, besides the v-brakes? would it work if i switched to disk brakes?
thanks!
-g

fietsbob

WHY? N+1.. Don't like it as is?, sell it and Buy the Bike You want,

[ Or if this is another Pre worry, and you didn't win the Bid, stop ]

rather than do those changes .. it's a fool's mission.

cplager

If you switched to disc brakes, you could go to 26" wheels, 20" wheels, whatever you wanted to. People do things like this on recumbent bicycles somewhat often. Without disk brakes, you just need to have brakes that would work.

Cheers,
Charles

LarDasse74

Changing the wheel size may be possible but it is likely to change the handling of the bike, and result in increased pedal strike from a too-low bottom bracket.

What is wrong with the 700C wheels? 700C is the standard size for CX, touring, road bikes, hybrids, and 29ers. You have practically unlimited tire choice (limited mainly by the clearance in the frame and forks), and the bike will work as it was designed.

What are you hoping to accomplish with this change?

Also, what model of CX bike is it and does it have mounts on the frame and fork for disk brakes?

LarDasse74

I very much doubt you could use 20" wheels on a bike designed for 700C... 26 inch wheels would possibly work OK, 24" would likely put the pedals very very close to the ground, and 20" you would only be able to pedal 60 degress at a time to 'ratchet' the bike forward. Brakes are not the only consideration.

cplager

You're right. I'm thinking of short wheel base recumbents where there's no problem with hitting the ground.

Cheers, Charles

fietsbob

Drop the tail end several inches the head tube angle goes down too..
even on a recumbent.

FastJake

V-brakes? No. Disc brakes, it would work but what are you trying to accomplish? As stated a smaller overall tire height will change the handling and make the BB lower.

cale

A 26" wheel sporting a 1.75" tire has an axle height of only ~.5" difference to a 700c wheel sporting a 28mm tire. These sort of difference aren't significant enough to impact handling. It's about the same as moving from a 23mm to a 35mm tire on a 700c wheel assuming you had the brake and frame clearances.

Airburst

Don't be so sure - I managed to put 20" wheels on a 26" wheel bike recently - I did have to use very short cranks, but it worked. Don't even ask how I did the brakes, it'll scare people.

Lexi01

How did you do the brakes?

fietsbob

yea but that 559 -47 tire wont fit in a CX frame,

made for a 622-32 tire, particularly the fork.

fool's errand ..

go get a hundred yard spool of waterline while you are at it.

AlphaDogg

The angle doesn't change if you're lowering the rear and the front equal amounts. Maybe I misunderstood what you said?

Airburst

Sections of an old rim - I mitred them to fit across the fork blades and seatstays in the same kind of way that kickstands do, drilled out a spoke hole on each one to admit the centre bolts on the brakes, then bolted them in place with the centre bolts. The brakes are BMX sidepulls, but the levers are absolutely massive, so I can pull them by the ends and the braking's OK. The bits of rim stick out a couple of centimetres each side, so I put duct tape on them to reduce the chance of them killing me if I ever crash the bike. I need to do something less bodged when I next get the chance, I might cut the canti bosses off and move them down to the right height if I can borrow a stick welder.

I don't feel too bad about cutting and welding on the frame, it's a BSO that was donated to the co-op, and it's severely rusted. It was in the "scrap pile" when I found it. The 20" conversion was mainly to see if I could. It works, and who the heck's gonna steal it?

JohnDThompson 

I'm thinking "Ted Shred"

LarDasse74

The question that immediately pops to mind is not 'how,' but 'why?'

cplager

I am curious about this as well.

I'm pretty sure you can probably change to 26" wheels. If you tell us why you want to switch, I think you'll get better advice.

Cheers,
Charles

cale

Possibly the OPer doesn't want his reasons debated. I'm not sure I'd want that either.

cplager

You're quite possibly right. That being said, I really am just curious. I already live on the dark side (ride a recumbent) and am quite open to people doing non-standard things with bicycles.

Cheers,
Charles

Airburst

The short answer is "why not?"

The slightly longer answer is "it was a slow day at the co-op"

fietsbob

Recumbents, predominantly, already have a small front wheel.

Bat56

Pretty sure OP wanted to know about potential problems and in order to answer that the reasons for the modification, or purpose of the modification is needed.

LarDasse74

Even if the angles don't change, the amount of 'trail' will. Head angle is only relevant in that it works with fork rake and wheel diameter to produce trail.

Retro Grouch 

Does first and only post tell you anything?