650 to 29er conversion?
 

Hello bicycle community!

I am inquiring about anyone's experience in converting a 650 vintage mountain bike to a 29er. I know many will have doubts, but what of those that have actually made it over this big difficulty! What say you?

Vintage 650b in a mtb... Don't really go together.
650b on mtb jargon is 27.5, and I wince at that term.
GT made an odd wheel sized mtb, in the pre suspension era to dodge higher import duty.

Tell us what you have exactly, make model, pictures even.
My instinct is you may not have what you think or how old do you think vintage is? Something in the description does not match.

29er is the same diameter as a 700c road wheel translating mtn to road jargon.

One problem is there are not many vintage 27.5 or 650b mountain bikes.

Even if you could, I don't see what you'd gain.

I have a Yeti SB5+ and a Yeti SB5 29er.

Two different tools for differing terrain.

@op Why do you want to do this?

Where are you going to ride the bike?

What suspension systems do the bikes have if any?

What braking systems does the bike employ? Discs or cantis?

How about clearances?

Will you need racks on the bike?

Lots of questions here......

If the bike was built was built for 650b wheels will a big fat 700c tire even fit the frame?

Bigger question- is it actually 26"?

Not many as in none.

I'd think the frame itself would be the decider. I've converted bikes from 700c to 650b, but it was a no-brainer from a frame point of view - if the frame designer had to fit a 700c with a specific size front and rear hubs, then it would have to fit a 650b. The same logic does not automatically hold true in the other direction. And likely isn't.

:lol: True.

Most bike mechanics in the vintage MTB days had not even heard of 650B. The size simply did not exist in the USA at all.

OTOH, I suppose by vintage the OP could mean like 5 years old...

Google is your friend: try "vintage 650B mountain bike" and see what comes up. Nokian made 650B knobbies way back when. Not a big seller, but there were a few builders who worked with them, as you will see.

But regarding the OP's question: If you are fortunate enough to have such a bike as a vintage 650B mountain bike, why would you bother putting 29er wheels in it? It's the second golden age of 26x1½/650B/ISO584/27.5er right now. Not only do you have more ways than ever to refer to the wheel size, there are more rim and tire selections that perhaps any time in history. Go with what you have.

Cuz if you read it on the interwebs it must be true....

I was there... NO 650b

It's possible there were tires in ISO 584 made for the European market. Not in the USA.

Unless by vintage you mean something much newer than I do.

29 inch had been around long enough that you can usually find a good 2nd hand bike. Frames are to be had too if you have to be the frankenbike builder like me. I just looked and saw 2 in Phoenix for around 700. Also a Karate Monkey in Tuscon for 500.00. Figure you can get the to come down a little, then consider the difference of what it would cost to convert a bike, assuming that's possible. I'd go for that Surly! I upgraded one to 1x10 and put on a suspension fork and it was awesome for a couple of years.

Raleigh Portage was 650b was a touring bike, but with its somewhat knobby tires and cantilever brakes it might be mistaken for a vintage MTB, especially if the handlebar has been changed.

That said, I don't see the point, and I doubt it would work very well anyway. Even if the wheels and tires fit, the brake bosses will be in the wrong place.

I googled and found zero. He doesn't want to be my friend. What did you find on google?

And if you didn't see it it didn't happen....

Not saying there were lots and lots. But it only takes one to be more than none. And I'm not saying I was anywhere near it at the time, cuz I was but a lad. All the same...
Tom Ritchey made at least one, around 1978, for himself.
And though raced as a CX bike, Jim Merz made a 650B knobby bike around that time too. Ridden by Tim Rutledge in CX nationals with a flattish bar in 1981. That's an off-road bike that looks suspiciously like a mountain bike, but is that too hair-splitty? Not sure what qualifies as a mountain bike to you.
Obviously the tires and rims existed at the time, and were being ridden off-road, in Europe certainly more than USA. But it wouldn't surprise me if there were some East coasters who experimented with the size too.

Acknowldeged. But like anything, you could get them here if you knew the right people.

I generally mean older than about 1990. What do you mean?

I don't think the OP has Tom Ritchey's one off personal 650b MTB. Therefore, he does not have a vintage 650b MTB. Because nobody made them.

Well, wait a moment. What do you propose to do to this bike, assuming you find it? Most (actually, ALL, I think) early MTB's had cantilever brakes; and the brake bosses are brazed to the frame and fork. Fitting different brakes that will work with a different size wheel is not really an option; that is, there may be brakes that offer enough adjustment in theory, but not in practice. So to make an old MTB work with a rim size other than what it was built for, frame modifications will be necessary. That's not a big problem, but it will involve a repaint and it will destroy any 'collector value" the frame has.

So...

It seems to me the bikes you mention are hand made and special bikes; they might even qualify as "historically important" and they certainly have some kind of "collector value." Yes, they exist; but they were not production bikes, and if you have one, you'd be a fool to modify the frame.

Huh, ya learn something new everyday! The Renaissance of the 650b Wheel. Ritchey, Fisher, Zinn, and Kelly toyed around with 650b frames. The French proto-MTB scene sounds pretty rad, hopefully there's some photos or videos around somewhere.

FWIW, there are 650B "gravel" tires, but 650B is more a road size than an off-road size. If you're riding off-road, stick with "29er" (700C) or 26" (559mm) off-road tires.

I'd be shocked if MTB isn't by far the largest market for 650b at the moment.

I've done 26" to 700c conversion.

https://www.bikeforums.net/attachmen...1&d=1424415293

In my case, I chose to use skinny road tires, and thus didn't have any big clearance issues. My frame also came without a fork, so I used a road fork.

I'm pretty sure 29er MTB tires wouldn't fit on the bike. :eek:

Note issues with the rear brake canti-pegs. I was able to use the bridge with my center pull rear brakes (not perfect, but workable), but the canti-pegs were in the wrong spot.

Disc brakes, of course, would help alleviate the issues with brakes.

Anyway, I could imagine a 650B bike with options to run either 700c or 27" road tires, or the 650B MTB tires. In fact, there are a few vintage road frames converted to 650B, and could presumably be converted back. Again, building a specific frame with disc brakes would help alleviate brake issues.

Thank you. That's all I'm trying to say.

I'm just wondering what happened to the the OP. Maybe with photos we would know what he had.

To enlighten the topic, read what Ritchey said.