I'm (somewhat) intrigued by the touted benefits of wide low pressure wheels/tires in 650B for road use but everything that I see available is way overbuilt for my requirements. I ride TX chip-seal at pace for century distances carrying minimal stuff in hilly terrain, not back country gravel or PNW back paths.

The favorite wheelset for my terrain (stole the front for a FG century recently) is a low spoke count AL/CF composite 16X20 Shimano RS-81 running supple 25mm tires.

A single "quality" 650B rim seems to be ~500 grams vs my entire wheelset at 1,500.

Don't try to pitch: "Wheel weight doesn't matter" to an old retired racer.
It most certainly does for me, on my terrain, at my pace and in the company kept.

So, what's state of the art in wheels to get a weight below '70's touring bikes for those interested in considering 650B for a trial?

Edit: See post #101 for a Much Better question, and it's Answer.

-Bandera

Well, I don't think you'll ever approach the weight of composite rims with the alu rims currently available in 650B. Fwiw, the Velocity A23 is listed as 435g. I'm not sure you can find lighter, but that's what I have on my go-fast Lemond Buenos Aires 650B conversion (and, for the record, I've never raced).

Uh, yeah that's back to Mavic MA-40 spec.
Been there on training wheels in the '80's, use them on my winter/wet bike w/ 28mm tires, they are very nice but plodding.

-Bandera

The marketing segments don't seem to overlap, do they?

I'm with [MENTION=45088]nlerner[/MENTION]; the velocity a23 would be near the top of my list as well.

Also, although you're saying wheel weight matters, you're also looking at substantially heavier tires compared to your 25's. Just based on a rough estimate by circumference without looking anything up, 2x heavier.

Edit... more like 1.6x heavier. Soma Grand Rando superlights are 300g, most others in 650b x 42 are 350-400g. Compare to 215g ea for 700c x 25mm GP 4000S II. Bigger tubes, too, 149 grams standard and 108 grams light. Compare to 65/112 for skinny 700's. So you're looking at roughly 3/4 lb more rubber, for 2 lb total.

Yup, guess you just have to work on the motor then.

Indeed.
If the purported low rolling resistance of wide/low volume 650B is indeed a of fact testing, much less adoption, by the traditional community of performance cyclists (even if retired) is hindered by any wheelsets suitable for fast paceline use where acceleration rules.

-Bandera

Pacenti CL25 are listed at 408g, those would be near top of my list. But I'm a 700 guy, always will be.

That "work" started in the Johnson administration and has produced fewer watts lately for some reason or other.

-Bandera

Maybe its time to change what cycling is to you? Your too old to race or ride/train like you still race, so why not try something different? There is not much point in comparing apples and oranges and complaining that they are not the same.

Man I wish I had gotten my 650B conversion of my Fuji done before went set in. Was too busy riding to mess with it. All I can say is that my original 27 inch rims on this bike were really heavy. I say that because the Velocity Atlas wheels/Compass tires I got dropped the total weight of the bike almost a full two pound.

Which "Apples" & "Oranges" would those be?

Perhaps you need to understand that there is a natural cycle of cycling for individual development with a progeression from "Junior" through "Emeritus" that has nothing to do with technical fads or doo-dads. It's about getting out on the the bike, however it is configured with some style and pace.
Not much has changed in how I ride in over 40 years, and why would it?

How a heavy 650B vs a much lighter 700C wheelset performs vs current fashion/hype is the subject of this post, not my Age.

Read & Work as "Fast After 50" by Friel details, or not as you prefer. I'll not do anything "different" as it still pleases me >40 years of cycling on.

I'll save you the trouble, for absolute speed on the road, 650bx38 or 42 or whatever is going to be slower than a 700x23/25 racing tire.

It's not so noticeable on most group rides where there's differing abilities but at the pointy end it is obvious. I switch between bikes a bit and I've never been able to hang with the paceline on my 650b bike. No problem with my 700c bike.

Wide 650b has a lot of benefits and I think that for most recreational riders it is a more sensible choice than 700x23/25 racing tires. However, if you want to race or emulate racers or just be really really fast, you're not going to be happy with 650b.

I've been running a 650bx42 bike since August 2015 and as soon as I run through the last two tires I have I'm going to sell the wheelset and go back to 700c.

Also, rim brake 650b rims are probably going to be a dead end so I don't really expect to see a lot of development. All-road and modern 650b designs are heavily invested in disc brakes where rims are building on mountain bike development and good carbon rims are already available.

I've posted this before but it's really the best illustration of my switch from 700c to 650b.

What's the weight of 70's touring bikes? My 650b univega (mid-range, nothing fancy) weighs ~23.8lbs with full coverage fenders and 38mm tires. I guess it would be nice if it was lighter, but I'm no racer.

Good input.
Never been dissatisfied w/ the carrying capacity/comfort of the traditional British Audax/Club designs fitting 700C up to 28-32 tires with mudguards for the last several decades for winter/wet/touring.
A proper road race design was required (and still is) for more spirited use.

650B seems to be an answer to a question that I never asked....

-Bandera

650b is about Rando, don't look for light wheelsets in that genre by many manufacturers.

I have not ridden 650b, have been told by many: 1. that 700c in frame sizes 60cm & above is the way to go. 2. 650b really makes more sense at 56cm and below

So I wonder why [MENTION=13607]cyclotoine[/MENTION] is a committed 700c type guy?

When I'm in shape, I can hang with some of the fast group rides here on my 650B bike. Wheels are A23 rims, shimano 5700 hubs, double butted spokes. Tires are the Compass 38mm regular version. Don't know what the wheelset weighs , but the bike is 24.5 pounds as ridden.

My go-fast 700C bike does indeed feel zippier than the 650B bike, but I only built the go-fast bike this summer and have not been in as good shape this season. However , the 700c bike has similar wheels: A23 rims, 5800 hubs, double butted spokes. 25mm GP4000s tires. The fast bike is 22 pounds.

I wish I had some objective ride data comparing the two bikes to share, but I don't track that stuff. My impression is the 700c accelerates and climbs better, but I certainly don't feel slow on the 650B and it's still really fun to ride.

If it matters, everyone will think you're a really strong rider when you do a group ride on a 650B bike with fenders. People tend to assume it's a heavy touring bike. I did feel that the 650B gave me a clear advantage on twisty descents, so smooth and it just sticks to the road while some other riders are getting rattled around by the terrible pavement on some of the local roadie hills.

Also depends on your paceline. I've got a Pelizzoli that takes 700 up to 32 and also takes 650b X 38. If there's a lot of acceleration/deceleration/surges involved, the 700 X 25 wheels wins it hands down. But in a constant high speed paceline, it is pretty much a wash. At least it is for my sixty five year old self.

Seems you had your answer before you started the thread...maybe time for a ride? Fill those water bottles with Ensure and hit the road!

OK, why "Rando"?
I just rode a century on a fixed gear 700x25, not interested in 1,200KM but how would 650B on touring weigh wheelsets have made that ride faster?

Heavy 650B wheelsets will keep them a non-starter for any performance riders when modern tech/could/should be applied.

MTB didn't hesitate.

-Bandera

Light 650B?
Bring in on!

-Bandera

650C/26x1"/ISO571 might be more what you want. This was always the go fast 26" size. It's not as retro hip as 650B, but it's still common enough that you could probably get a pretty light wheelset. Used to be a tubular version too, but not sure rims are still sold. Haven't kept up.

650B was historically a utility/touring size. It kind of still is. Even so, 32h A23 650B wheels with light tires could be OK.

I've only done one brevet on my 700c road bike, a hilly 200k. Loved it, but even without any chance of rain in the forecast I would take the 650B for 300k and up.

It wouldn't. But by getting the extra volume tire in there, it'd almost certainly make it more comfortable, so you'd actually have a chance to finish.