lungimsam

Do Randos prefer one o'er t'other?

If so, why?

skiffrun

Yes.

jimc101

Why would you want to use 650b? The availability of them (tires, rims & frames) is poor compared to 700c, the vast majority of commercial frames are designed for 700c, getting spares on the road would be an issue.

650b is an old size, old and practically obsolete for road use, new and possibly up coming for MTB, although going by the 29er hype from a few years ago, and the number of riders I see with them; 26" will be here for a long time to come (in the UK at least, the US does seem to have taken much more to 29er).

Looking at current bikes available, the QBQ ranges (Salsa & Surly) use 26" on their smaller frames, most of the Thorn range is 26", which manufactures give 650b as an option?

unterhausen

I have seen quite a few wheel replacements on brevets, and with 650b that would be a ride-ending problem. I knew 2 people that needed new wheels on PBP. You could buy a 700c wheel at most controles.

There are plenty of people that use 650b successfully. I expect some of them will chime in shortly.

Hairy Hands

There are some advantages to the 650. Smaller rim = lighter weight, less rotational weight, greater acceleration, overall height of rim with tire is less than equivalent 700c, overall height of bike lower, and many say the handling is better with the smaller tire rim combo.

Negatives are: harder to find tires, must order almost exclusively on internet(expensive) and carry spares around with you, with few exceptions you will need a custom built frame which will limit you to steel (if you care about material choices), and are generally associated with retro type designs.

Cant think of any more at the moment. Jan Heine seems to be the biggest proponent and promoter of this.

unterhausen

I have a 650b bike that I will probably ride on some brevets and use for commuting. Need to get a spare tire. The rims I got (Velocity Synergy) seem to be relatively heavy in comparison to the 700C version. A lot of people have converted 700c bikes to 650b -- you just need longer reach brakes. If you use a larger tire, it doesn't change very much about the bike.

Hairy Hands

Unterhausen, I read your post further up the thread and I thought I remembered your were building a 650b a while back. I was surprised you did not have more to say about the subject seeing as you have one. Everything I know about the 650b is from reading Jan Heine's articles. I originally started out wanting 650's on my new build, but I also wanted a CF frame. When I found the frame I wanted it had posts on it for cantilever brakes. That killed my 650b idea.

My new bike is not completed yet, but one of the things that immediately is noticeable is the standover height. Compairing the new with the old bike the height of the bike is several inches taller. Both frames are 58cm. The only thing saving me is the new bike has a slanted top tube, Im curious how the height difference will effect my perception of things when riding it.

Another one of Jan's claims is that a 700c rim with a tall fat tire will be inherently more stable straight line vs the 650b with same combo, but less nimble in the turns. I would think the straight line stability would benifit a person when they cant hardly keep their eyes open.

unterhausen

I try not to ride when I can't keep my eyes open, but I think nimble is always better. If you get sideways with a more stable wheel, it's going to be harder to recover. But I'm not sure there is that much of an effect. If there was, it would be even more noticeable with 26" wheels, and I can't say that I have noticed it there.

I'll probably just use the 650b bike on 200k's and maybe a few dirt roads. Not going to be my primary bike. 650b used to be the preference for utility bikes. I guess it fell out of favor when those kinds of bikes were supplanted by mountain bikes, which is a shame. I think the 650b tire choices are going to continue to get better, but they will definitely be on the hefty side.

mulveyr 

As a guy who rides a small frame ( 50-52cm, depending on the geometry ) and has both 650B and 700s, I definitely prefer the 650B for most riding. I get toe overlap on all of my 700's. From an aesthetic point of view, 700's simply look too big to my eye on small frames.

In terms of tire/rim availability, yes, there are fewer options. You can still get everything from puncture-resistent tires to fast "event" tires, though you're not going to generally find them in your LBS.

For tire performance - well, when I'm riding with my 11-year-old, who is on a frame not much smaller than mine but has 700x25's, while I'm on 650Bx38's, I still beat him by a large margin when we've tried roll-down tests on hills. Plus, it's rather nice than I can go from smooth pavement to gravel and not even have to think about it. ;-)

650B is definitely "faddish" at the moment, especially in light of the easy availability of 26" tires/wheelsets. I suspect it will stay a niche, but still entirely viable size for a long, long time though. It meets a nice need for all-rounder bikes that aren't quite met by most 26"/700's in certain frame sizes.

Carbonfiberboy 

When we group up for a brevet here, one might see one or two 650B machines out of a hundred bikes. The rest will be 700c. Many carbon bikes, many TI bikes, several aluminum bikes, a few steel bikes.

Commodus

I like my 650b bike. I think it comes down to tire selection ultimately. If you want to run very large tires, things get a bit awkward with a 700c size, both in terms of handling and construction. Since the roads our organizers send us over here in BC are pretty random, and sometimes not roads at all but trails, I like my 42mm tires a lot.

Of course I've done these rides on my racing bike too, it works fine. It's a bit more tiring and the chance of wheel damage is increased of course, but then there is also the advantage of the much lower weight when conditions are good. This is the primary disadvantage of 650b, the added weight of the larger tires.

Some people talk about availability as a disadvantage, but I don't think that's really relevant. It's no big deal to bring another tire, and ordering enough tires off the internet to keep a stock on hand is simply done. I suppose a catastrophic wheel failure will keep you 'grounded', but I'd hate to find out what kind of obstruction could destroy a nicely built 32 spoke wheel shod with 42mm tires at 55psi. I've certainly never encountered one yet that wasn't easily avoided, and I have to think if I failed to do so, walking and breathing would be my primary concerns afterwards.

unterhausen

there is definitely some comfort in having bigger tires. I remember before I got my current lights, riding at night with 25mm tires could be a little stressful because I was afraid of hitting a pothole at speed. I've been doing a lot of gravel road riding, and even 32mm offer a lot more margin.

mulveyr 

Yep, I mostly ride at night due to my schedule, and even with a dyno light setup sometimes I get a little overenthusiastic and outrun them... straight into a pothole. ;-) I suspect that the ones that make me say "Ooops, that was dumb" on my 650bX38's would have me looking for all of my tooth fillings that had fallen out on my 700x23's...

unterhausen

I double flatted within 5 miles of the start of a 300k when I hit a couple of big potholes in the dark. Don't know if bigger tires would have saved that from happening, but it was pretty stressful. Even though I finished, I never fully recovered from that setback.

StephenH

I hadn't really thought about it, but a friend of mine recently got a Bacchetta recumbent that's 700-size, but she mentioned a lot of the older Bachettas were 650- they were just now going to 700s across the line. The significance around here is that most of the 650's you'd see here aren't on upright bikes. Which also means tire availability should be a little better than you'd imagine.

Similarly, I saw a kid-size racing bike the other day, and it's hard to imagine that thing would be in production if the wheel size wasn't being used on some recumbent somewhere. Or maybe it's the mini-velo fad, but either way, it gets some odd sizes in production.

Steamer

Bacchettas have been sold with 650C wheels (not 650B). 650C is ISO 571. 650B is ISO 584. Then you consider that 26" mountain bike wheels are ISO 559. Three wheel sizes with only very small bead seat diameter differences between them. Well, crap. If you took the tire availability in each of these sizes and somehow made them all the same BSD, then you'd have pretty much every possible type of bike tire and use covered. Unfortunately though, things are fractured, and will likely remain so. It may even get worse as time goes on. For a while there all road bikes were 622 and all mountain bikes were 559. The world made sense. Now, we have road bikes with 584, Tri bikes with 571, mountain bikes with 662 and 584 and 559, and recumbents with 622, 571, 559, 520, 507, 451, 406, 355, and 349. Well, crap.

unterhausen

and that's just your one bike

Steamer

Of course your joking, but I have, in fact, had at least one contraption using each of those wheels sizes except 571 and 349. But they're out there.

BenHud

I have one bike that I switch between 700c and 650b. I like the cushier ride with the wider tires, other than that, I don't notice much difference between the two. My average speed is about the same with either wheel size. The main advantage to me of 700c is the greater availability of tires. I don't worry about wheel failure with the 650b. I've never been on a brevet where I felt like I could've found a replacement wheel of any size, and still been able to finish within the time limit.

pdlamb

Seems to me the real advantage of 650B is that you can fit a wider tire on a frame that limits the size of the 700C it was built for, assuming you can get the brakes to work. That lets you ride wider tires at lower pressure without getting a new frame.

It would, therefore, seem reasonable to make sure a new bike fits 700C.

Exceptions are people who ride smaller frames (can somebody cue up a chorus of "Short People" please?).

One other note is that most 650B tires are (a) expensive and (b) thin. Lower rolling resistance than a similar (>30 width) 700C, and probably lower lifetime as well. It's hard to find a 700C tire >=32 with thin sidewalls, for instance, because most of these tires are sold for tourists (carrying a load and not wanting a flat) or hybrids (don't want a flat).

MileHighMark

Bike Fit > Wheel Size

Commodus

Wow what a random comment.

Trouble

I can see no advantage going from a 622 down to a 584. I can see going up from a 26" mtb application though.

Here is my reply for later use:
Currently on my 29er I am running a 622-60 Big Apple and the tire/wheel combo is huge and really, really cushy. It's a tubeless application and the 30psi is great for urban assault riding.
On my 700C road bike, going up from 25 to 28 tires was a huge advantage and I run them at about 80-90psi front/rear. The long distance bike I'm having built will use 700C wheels, but I won't ride anything smaller than 32 tires.
So...for me, no 650B. I like big wheels, the roll over stuff nicely and as far as one comment about being less nimble...I can flick those BA around just fine, so I don't buy that at all. The other comment about weight and acceleration is so over used and unfounded... minimal at best. I can spin up those BA just fine and once I get rolling look out.
As far as the other issue discussed about availability. I wouldn't let that stop anyone from going with the 650B.
If you're a shorter person, maybe 650B makes sense.

MileHighMark

Not entirely random. Many folks look to 650B wheels as a magic bullet. I've ridden 700C and 650B, and they both have their pros/cons. I think it's more important to choose a bike on fit/function, and then accept the corresponding wheel size.

chriskmurray

I am with him, proper fit should come before all else on a bike and if smaller wheels can help make the bike fit better I would certainly say go for it.