LeicaLad 

Nice to see this thread brought back to life. Some fine examples shown here.

This is a spur-of-the-moment conversion, just to see what it would be like. With only a short shake-down ride to judge, it is, at first blush, quite marvelous.



This is a 1971 Gitane TdF. The wheels are a 105SC set at 123mm, giving me 7 speeds. 38mm Col de la Vie tires.

The brakes are r559 and stretched to the limit in the rear. BB is slightly lower. I'll need to watch this carefully during initial rides to better assess!!!

bear_a_bug 

Better toss this one in here while I'm at it...


1980 Fuji S12-S LTD.

Running VO Diagonale rims laced to Sunshine Gyromaster hubs. Tires are 42mm Compass Babyshoe Pass. Dia-Compe 750 centerpulls on front and rear.

Just the most natural, comfortable-all-day ride. I'm gonna enjoy running these tires down to the last mm of tread.

pcb 

I've been easing off my 650b conversions after scoring a proper 650b Boulder All Road. Had this Waterford RS-22 setup w/650b last year, for a bit, but the bb wound up a bit too low for comfort. The cush from the Somas was nice...



Like the Voodoo posted here a few years back, discs on this Waterford X-14 does make 650b conversion a little less challenging. The Hetres fit fine, bb height seems tolerable so far. There's some C&V heritage with Waterford steel, and Nitto Noodle neo-retro bars, but the sensitive might want to avert their eyes.

mountaindave 

Found this thread a while ago and briefly investigated 650b conversions. I didn't give it much thought (other than, "What are these weirdos doing?"). I thought I could handle any gravel with the proper 28's. But after a long weekend on some brutal gravel (the Cino) with my wife comfortably riding 35's on an old French Gitane TdF, I finally decide to further investigate 650b conversions.

My very first road bike, and '88 Specialized Sirrus, has been a test bed for a number of "modifications" over the years. I have ridden it three times on the above mentioned route and it wasn't terribly fun on the gravel so it was the logical choice for the conversion. Many thanks to the Bikeman's blog on conversion guidelines, his metrics allowed me to determine that my bike would be suitable for conversion (and I am happy so far - everything fit just as expected, BB isn't too low).

I got some cheap 650b wheels from uglyrm on eBay. At ~$110 shipped, they aren't bad and were an economical way to do a quick and dirty conversion. (Be prepared to true them up and adjust the cones, they might not be perfect.) I managed to retrofit some cheap Cherry centerpulls from a '72 Centurion Super LeMans, added Kool Stop pads, fit some old housing and brake cables, threw on a pair of Pari-Moto blackwalls, and I was in business. I also decided on a 12-30 8s cassette that I am currently only running as a 1x8 with the 42t chainring (yes, the short cage RD has no trouble handling the 30t sprocket).

I initially intended only to ride a little ways up a trail tonight, but ended up at the top of the hill as I was able to just keep going and going. The Pari-Motos have decent traction when aired up to no more than 45 psi (their recommended minimum, but they still felt a little stiff compared to Panaracers). The bike feels almost as fast as before, but there did seem to be some perceived increase in rolling resistance (could just be my imagination).

I blazed down the trail and had to stay on the brakes most of the way. I didn't have to worry about locking the back wheel up and skidding out - the brakes are not nearly as good as the 105 single pivot brakes they replaced. The Kool Stop triple compound can't make up for poor stopping power. However, on typical gravel roads, this won't be an issue - they bleed speed just fine. It was just after sunset and I couldn't see the trail terribly well. It's a great trail and there weren't many large rocks to dodge, but I didn't have to worry about them anyway, I just floated over everything.

It was a very enjoyable shakedown ride. I like it enough to consider doing some more conversions of other bikes with better wheels and brakes.

Here's the build:

whatwolf

1986 Trek 400, converted to 650b (and low trail)

I rode this bike for Cino with @mountaindave above, and was surprised not to see more 650b bikes there. The 42mm tires made the descents crazy fun and only a little sketchy.

Darth Lefty 

Those of you complaining about low BB's, have you considered shorter crank arms? This is a question and not a suggestion, would it suit you or drive you nuts to have shorter cranks?

mountaindave 

A beautiful bike and a great build (TA cranks are particularly gorgeous). Now that I've done my conversion, I'm surprised more people don't do it either. It is a bit esoteric, but given the fact that 650b was quite common on randonneurs back in the day, I would assume that they would be promoted more for the Cino. Or perhaps we're all just expected to suffer.

djkashuba 

I love how you have used some really accessible parts and have made them yours. This bike seems as much composed as built. The bag of course is unique.


Cino Heroica 2015 by djk762, on Flickr

mountaindave 

If it seemed advantageous, I loved the bike and it was feasible, I'd go shorter cranks without question.

velofinds

Prematurely wading into this thread. I'm super pleased to have just bought this neat-looking bike (though I don't have it in my possession yet) and am mulling the idea of a 650B conversion. The question is, does it look like it would take? I'd also like to run fenders, so that's yet more clearance to consider.

Naively, I assume this and the PX10 are roughly comparable geometry-wise (seller confirms this, too, as he owns both), but I would welcome any different views based on what is shown here. To my untrained eye, clearance between the stays looks tight to me.











The fork, on the other hand, looks like it has a decent amount of clearance:

velofinds

@nazcalines, thanks for the reply. Do you have before and after photos of that bike?

mountaindave 

+1 the only way to tell is to get it in your hands and measure. That being said, Bike Boom era bikes are usually pretty good candidates.

mountaindave 

Some photo help:

Before:




Interesting choice to go 1x, but I like it! So clean and simple.

velofinds

@mountaindave, what do you mean by "1x"?

@nazcalines, very nice. Is a 38mm tire the widest you can fit?

mountaindave 

As in 1x6 drivetrain. There is no front derailleur, so the crank is a one-speed. Simple and sexy. Only a real man can handle such a beast!

exmechanic89

Hey a quick question.. currently 650b is really only used on mtbs, right? Because I really like these road bike conversions I'm seeing in this thread, and plan on doing one myself soon.

In fact I have a '91 Trek 750 (hybrid) I'm thinking of using for the conversion. It's all OX tubing and is fully lugged. I bought it as a bare frame and have it currently built up with v-brakes, some spare 700c wheels, and some other random parts I had. My understanding is that the 750s of that year had the same geometry as the 520 road bike, and I was originally thinking of converting it to an outright road bike. But now I'm thinking this might make a pretty cool 650b-er if clearance and brake issues all work out.

gugie 

I agree, that came out marvelous - veryclean looking!

gugie 

Not at all. Lots of 70's-80's steel framed bikes are perfect candidates if you like fatter, performance tires, and especially if you like (or need!) fenders. A bike built for 700c, even 27" with skinny tires can become much more comfortable, and allow for non-paved riding, with fatter tires. Reduce the rim diameter and add it back with tire.

The problem with your bike is probably brake reach. Find a pair of 650b wheels to try out and see for yourself. You're in greater Portlandia, correct? I happen to know a guy, he sometimes answers to the name Crapmaster...could be arranged...

gugie 

Very nice! @Velocivixen, you watching this?

Velocivixen

@mountaindave - That's a nice looking bike. The simplicity really forces the eye to see the frame. Are those Symmetric Suntour shifters?

@gugie - you mean for the 650b aspect or Univega aspect?

LeicaLad 

Thanks, and I haven't changed back. It was such an easy conversion, and it really does ride nicely.

It's part of my full-time rotation team, for sure.

rhm

I've posted these photos before, but perhaps not in this thread... so here's mine.



The frame was originally a 1976? Holdsworth "531 Special" that someone had modified by adding fender eyelets, top tube cable guides, bosses for two water bottles, downtube cable stops, eyelets for front and rear racks (different from the fender eyelets, so presumably done at a different time). Apparently someone wanted to use it as a touring bike. That wasn't my plan, but then I thought, oh, why not?

So I did:

As a touring bike, it was fine. Rode some 600+ miles through NY State on 650b Col-de-la-Vie tires.

Since that tour, though, the bike has reverted to a 'rando' form with the handlebar bag almost always in place, and a removable bag on the rear:



Hetres are an incredibly tight fit. But they fit! Speaking of hetres, you've seen these before; I got them second hand.

I'm using 165's. I wouldn't mind something shorter, but it's hard to find anything shorter than 165's. Certainly nothing attractive.

mountaindave 

@VelocivixenThe Univega belongs to nazcalines, I just posted the large photos. But I agree, nicely done!

@rhmhow do you like the hetres vs the col de la vies?

rhm

@rhmhow do you like the hetres bs the col de la vies?

Well, if I could give the Col-de-la-Vie a report card, it would read as follows:

Ease of mounting------- A
ease of seating-------- C
puncture resistance---- B+
comfort---------------- B+
reliability------------ F
___________________
Final grade------------ F

Comments:
I mounted the tires without difficulty, and got them seated satisfactorily. On a 600+ mile fully loaded through upstate NY state, they rode fine. Punctures were not a problem. But on the last day of the tour, while I was eating lunch, the front tire just blew out. The sidewall separated from the bead without warning, and of course the tube exploded instantly. Had this happened a little earlier that morning, when I was screaming down a road out of the Adirondacks at top speed (say, 35 mph), that could have been very ugly.

The tire was new; it hadn't been ridden 700 miles. There was no sign of damage that might have caused it to fail. Based on my experience, I cannot recommend this tire.

So far I haven't had any problems with the Hetre. A few punctures, two of which couldn't be explained, but that's presumably not the tire's fault. They are gradually growing, as expected, and this may one day cause me problems. At this point I'd give them a passing grade. But they are not so amazing that I have to sing about it.

noglider 

@rhm, you're giving the F grade to which tire, the Hetre or the Col de la Vie?