RockiesDad

Seems like a few bike companies are coming out with 650b size wheels as standard fare, ie. Kona. I was wondering what is the pros and cons of each wheel size? I know you can fix fatter tires with the smaller wheels but do you sacrifice speed or anything else? Gains are comfort or maybe quicker handling maybe? Problem is that there isn't too many choices if you want to upgrade wheels and tires. Well, not yet. So is this just another marketing sideshow or is it here to stay???

Spoonrobot 

Both.

Came from a combination of mtb companies overshooting the mark when going from 26"->29" and having to come back to a smaller size (27.5/650b). And from road riders wanting to re-enact a randonneuring trend from the 30s/40s as their bodies aged out of high pressure 700c sized wheels. It's not going anywhere because it allows gravel-themed bikes to be designed with the same clearance levels and parts but to fit both 650b/700c wheelsizes in respectable widths.

FWIW, I found 650bx42 to roll slightly slower than 700cx42. Noth enough to bother me in my regular riding but significant anytime I was riding in an event or with other riders. Or when the terrain was especially bumpy. Or at the end of very long or very hard rides.

It's about the same as 26" and 29" in the mtb world, rollover, moment of inertia etc. There are differences but mostly it's preference with a splash of what your physiology prefers and how tall you are.

650b is much closer to 26" than it is to 700c:

tangerineowl

Would be good if you can test ride a bike with 650x42, 47, and 700x40+
see how different the feel is.

I do like the nimble feeling of 650x47.
Wouldn't go to 42 though, as I feel the tire is too small; just feels a bit weird/slow.

Andy_K 

I think the biggest advantage of 650B for new bikes is that it lets you do things with the geometry that you couldn't do with bigger wheels, especially on smaller frames. For instance, 700x40 tires require longer chainstays than 650x42 tires. Obviously you lose a little air in that transaction, but for most gravel riding 650x42 are plenty comfortable.

Personally, I'm in the camp that's using 650B to retrofit wider tires on an old road bike. I recently built up a 1974 Motobecane Grand Jubile with 650x38 Panaracer Pari Motos and a 10-speed Campagnolo drivetrain, and just to be sure I was in full 30s/40s randoneur re-enactment mode, I raked the fork a bit to give it low trail. It's a very fun bike to ride on gravel, but possibly not quite as well suited to it as some of the best modern adventure bikes.

HTupolev

Smaller wheels allow you to use wider tires with greater geometry freedom and reduced rotational inertia. You may be able to use shorter chainstays if you want, front-center can be lower for the same trail without cramping the available space, etc, and the bike can feel a tad livelier, than with a similar tire on a wider-diameter wheel.

Depends. The notable caveat with lower wheel diameter is that don't roll as nicely over tall irregularities due to the angle of attack. That's a vanishingly small effect on most surfaces, although on bumpy roads and trails it may matter. They also *might* lose a bit more to hysteresis as the tire flexes as it rolls, but if so, within reason it's also a very tiny effect.

If a 700c wheel size would otherwise have prevented you from using a tire width appropriate to the surfaces you're riding, then gains also include speed.

I think tire selection is actually alright on the high end. Far less choices within each style as 700c, but there are decent options for nearly anything.

catgita

I have two bikes to compare. One with Compass 650b x 42mm. The other with 700c x 38mm. It is hard to tell the difference really. The 42s maybe a little smoother, more stable and sedate. The 38mm a little more responsive, still very smooth. I think they are equal in speed. I can't tell the difference in acceleration or steering inertia. Neither likes deep sand or soft surfaces, but they manage OK, nor do I want to ride them over large rocks. I am very tall, so geometry is not restricted either way. Unless you are using disks, rim choice is very restricted on 650b, but not 700c.

Wspsux

I think It depends on your pavement/offroad split. If you spend a significant time on pavement I'd go for 700c with something like a 38 mm compass tire. If you're off road more 650 x fat as you can fit.

RockiesDad

Yeah this crossed my mind too. Recently I've been spending more time on road than gravel and was thinking that my 35c tires might be too big. Might go down to 32-33c on my next set.

Now if I spent more time on gravel then 650b might be something to consider since bigger tires are better for this.

Will continue looking for an aggressive steel framed adventure bike with 700c wheels. Lots to choose from...

u235

Yes, chances are if you have a 650 wheel set laying around and disc brakes, they will bolt on to a 700c gravel bike with no problem and work without issue. Just for kicks, I mounted my 26x2.1 wheels on my gravel bike. My 26 wheels aren't disc so I had no brakes but it would have worked fine.

DiamondBack Carbon EXP is a nice flexible all purpose bike that ships with 650b.

Metieval

How Should I start? I am looking at 650b, because I want volume and I don't know of any 700x40 slicks. Well supposedly the WTB byway takes nothing away from the WTB Horizon, except maybe slower tramac carving? So there I am going away from slicks already. apparently there isn't much if a demand for slicks beyond 30c in the 700c world.
I love my 700x40 MSO, I'd probably love the 36c MSO just as well and Probably the Gravelking SK 700x38/43.
However 650b gives me a few things I am looking for on a large ride that is in the planning stages. Stiffer wheels, and a level of cush that 700 won't give. and I don't really feel like rolling 1,000's of miles on MSO's or Gravelking SK's on pavement.

Honestly I'd probably rather go roll 10,000+ miles on a 30c tire and stick to tarmac. But If you were to only do a huge adventure ride once in your life, wouldn't you too prefer to roll a 650x47 with a go anywhere you please tire?
We're talking Katy trail, Kansas gravel, Nebraska Gravel, Chip n seal, dirt, whatever is in South Dakato, Wyoming, Montana, Idaho, Oregon, West coast, CA sand, AZ, TX crap, southern coast stuff, Sand FL. Carolina Gravel. maybe some Georgia gravel (if it's dry).
I'll be on a bike that can roll either or, so If I want to camp out somewhere for a few days, and wait on a package to do wheel swaps so be it. which might be tempting. I could ride 800 miles on pavement/crushed limestone on 700's then swap out to 650b for Kansas/Nebraska. Then again I could just roll the WTB Byways the entire time, replacing them when needed, (before) most bike shops along the way could get them within a couple days. and a couple day break a few times isn't that bad of an idea.

I've played around on a Cannondale Slate and it was super fun. However I don't think the 650x42 is for me anymore than a 700x23 is for me. Just as anything beyond 40c in 700 isn't for me.
I think tire diameter is just as individual based as are chainring teeth and crankarm lengths. Sure we can all jump on a road bike with a standard crank arm, and a compact double, and ride it. Once we experience custom, off the shelf bikes rarely cut it anymore.

as for the 650/700 gravel/adventure tire thing. I'll relate to my Road bike. I don't want a super thin clincher race tire, neither do I want a Conti Gatorskin/Pro4 Endurance tire. There is a middle ground with a tire like the GP4000sII. Likewise I don't want a fragile Compass tire, neither do I want a burly gravel tire.

btw there are like 5 Manufactures all pulling the Dropped drive side chain stay to fit the larger tires all while keeping a short chainstay.
Which means I can run a 650x47 tire on a bike that gives me almost spot on Cannondale Synapse Geometry on 700x30's. I'll never forgive Cannondale for giving us the Slate rather than a Synapse than could run a 650x42/47.
Well I might forgive them enough to buy a di2 SuperX to park next to my di2 Supersix.

Metieval

I am guessing that tire size is about need & personal preference. So many GOOD options for 32c.
Donnelly (formerly Clements) Strada USH, Gravelking (tubed) 32c, Donnelly even has a new tire Strada CDG in 30c (I'd ride it on gravel), WTB has the Exposure line 30/32/34 (each one having more side lugs). All depends on distance, and gravel conditions though. Most of all our Ohio gravel roads have a packed limestone dust surface on it somewhere, making it almost smoother than our chip seal roads.
IMO frames play a huge impact on ride comfort as does tires. My alloy synapse was more comfortable on 25's @ 95 psi than my Trek Crossrip is on 40c @ 45 psi

and what do you mean by aggressive on frame?
https://www.chumbausa.com/terlingua-700c-650bplus/

Marcus_Ti

Nice thing about 650Bxfat---you get a lower riding bike that is more stable on unstable ground at speed...even with significant BB drop, 700x40mm tires put you pretty high-centered off the ground. Also 650B conversions let you run bigger tires frequently--and tire width is more the limiter than tread style on gravel roads.

Hehehe.

Yea over here your 32mm tires would be good enough for our paved roads....But our dumped pea-gravel, or non-compacted dirt, country roads want a 2" class tire, or as big as you can run.


Thinking about giving Terrene Honali 700x50 tires a try next year: Honali | Terrene Tires

Metieval

My Trip planning (loosely at the moment) Is running West through Southern IN, IL, hitting the Katy Trail, then dropping into KS below Kansas City. So coming up passed Ottawa, between Lawrence/Topeka to Lincoln. Unless there is enough reason to follow river up to say Nebraska city then head west.
Regardless that's for another thread.... You guys have some serious Minimum Maintenance roads that almost are not roads! or even driveways! like farm equipment only stuff maybe? lol I don't know how much of that I'll want to ride loaded (well 30-40 on top of my 190), but I'll for sure want to experience it! MY other reason for just picking the WTB Byway.
Now for the worse part, it will be May/June ish so kinda wet, but hopefully after the rain is done.

Metieval

so ummm Looking into Nebraska and Dakota. BIg floaty tires seems to be a requirement

Marcus_Ti

Depends on your luck with the weather. In the past 5 years....In June we've had everything from flood conditions (Brownville was under feet of water)...to complete and utter drought (The Platte River completely ceased flowing and was bone dry). The drought was so bad all the farmers gave up and harvested their fields, and mowed down the leftovers for hay---by friggin Memorial Day (which never happens). This last year, was mild-warm in June and wet/cold in August.

The river does have a few breweries/wineries nearby (in Brownville there was a winery that was still open when Might Mo left its banks). Along the Cowboy trail there are a few nearby too. Cowboy is nice as it mirrors the highway, but is separated by 50 yards or so--so no being buzzed, it also tends not to be so pea-graveled.


I can ask about the Katy, as I know an amigo down in KC in MO. Generally the MMR in NE are faster riding than gravel country roads, so long as it is dry...but overwhelmingly both MMR/gravel are much safer/friendly and lower traffic than pavement in Nebraska. Unlike say CA with its technical fireroads, MMR/gravel in the Plains are soft and steep but not twisty or off-camber.

Metieval

As far as i know much of Katy is paved, and maybe some crushed limestone. Kinda blah riding maybe but have to do it. (not real big on bike trails) I mean they are good, but is usually old rail way lines so its just bland and lots of trees on both sides. Good when it's windy. I've been across I-80 3 times in my life. It's time to go see stuff no one sees. another reason for the 650x47

LesterOfPuppets

Compass Snoqualmie Pass is a 700x44 file tread

tangerineowl

Re the Compass tyres being fragile, I think it depends on the terrain / rider weight / speed etc.

Using the 650x48 extralights setup tubeless, on the road and gravel. I switch out to ThunderBurts for the rockier singletrack.

If I raced I'd probably look around elsewhere, but at a casual to steady speed on an all-day ride, I find them really good for exploring around.

Spoonrobot 

Compass tires also benefit significantly from being aged before use. I’d recommend buying a pair and letting them sit out of the package for a few months before riding. Or riding the tire as a front tire for a few weeks to get some uv and outside exposure to harden it up a little before putting it on the rear.

I know this is often regarded as unnecessary with modern tires but my experience with compass tires specifically shows flat resistance improves as the tires age. There’s something different about the rubber Panaracer uses for this brand compared to all the other tires they make.

u235

Are there more 27.5 slick choices? I've never looked or considered it.

I've had wider file tread tires that rolled with less resistance on the road than some narrower slicks.

Metieval

IMO because of the touring and the nature of market demands, yes 27.5 has far more, and better options for a fatter tire than 700 series tires.
As per the deleted post.... and replying to it. the Conti Speedrides will ride with similar rolling resistance as many less desirable 700 slicks. (Sport contact, gatorskins, pro4 endurance, etc...) with the difference being in weight.
Conti speed rides (430/495 grams) are not tubeless, with 100+ gram tube that now puts me on par with a 515gram WTB 27.5 road plus Horizon tire. While I have never actually roll tested the Conti speed ride to a 650 WTB Horizon, I can imagine the roll resistance winner will be the WTB Horizon. Put that Conti speed ride up against any 650 compass tire, and the Conti speedride (not a bad tire btw) will lose.
I absolutely love my 28c GP4000sII tires which measure 30c, Conti offers me a 4Season in a 32c.
I would love to see many of these higher end road slicks go to tubeless and 32/35/38/40c, but until they do.... 650 will be my game. and even then, I don't know if I'd pick one as the WTB Byway is what is on my radar right now.

Where is the limit for road plus on 700? IMO once we start going passed 32c, we might as well do 650... which is where the market is right now.

First world problems, I love it, I also love options.

I am probably not your run of the mill tire guy either. I'm spoiled.

Banzai

Too much over 700c x 37, and you start to creep up into "29er" tire range. Very few tires in the 40mm plus range for 700c, because you're just that close to 29"x1.95".

Marcus_Ti

You want a fat 700C slick, the Gravelking comes in a 700x38 slick.

Problem you run into though...what is the point of a fat slick, if not fully-bagged touring off road? Usually if you don't need a knobbie tire, your need of a fat tire isn't that big. The hardpack rails-trails around here are rideable on narrow 700x25 roadie slicks even.


The limit for 700C is your frameset....which unless you have a longer-chainstay disc brake bike and a fat-tire fork or specialist gravel fork (there are only 4 or 5 of them), the limit is probably right around 700x40, simply due to frame clearance. Which is more commonly a problem on more racy framesets that try to keep the rear-center short for agility. What is more, on such frame sets, the gains from going 650B aren't as big....often barely clearing a 650Bx47 if that.


There's a funny thread going on over in General I believe...still... It is about crankset Q factor being too wide today, and wondering why variable Q-factor isn't a sizing thing from OEMs. Q-factor is part of the problem with tire clearance. Roadie or road "compact" or "sub-compact" cranksets all are designed around a narrower BB (coming from that old 68mm BB standard versus MTB's 73mm) and Q-factor....that narrow(er) stance limits gearing choice due to cogs clearing the chainstay....that chainstay clearance adds to the tire clearance woes.

Metieval

well well...... I appreciate this topic more than ever!
So I was looking at Panaracers website on gravel line up and they have a (new) 700x38 gravelking TLC 320 gram!
super hard to find, and 320 gram it doesn't sound very durable. Regardless, I bet it's a super fast tire!
only place I could find them.
https://www.bike-components.de/en/Pa...l-2018-p61146/

Marcus_Ti

Another option more availaboe now is Vittoria's Terrene Dry.

Vittoria Terreno Dry And Mix 40mm Tires: Getting Rolling -

Not fully bald, but does roll quite quick IME. Also is TCS, so it snaps in tighter and holds than Panaracers.