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WTB Develops New 750d Wheel Size

Aug 28, 2023
by Dario DiGiulio  
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For the dozens of you lamenting the static nature of the wheel size debate over the past few years, this one's for you. WTB has announced their development of a new wheel and tire size, primarily focused at the gravel market. The new 750d distinction is currently aimed exclusively at the custom-built-to-order market, as the diameter is large enough to require specific frame geometry.

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750d is not meant to replace the tried and true 700c, but merely complement it and cater towards taller riders and those who want a more efficient ride over washboarded and rougher gravel roads. The larger wheel size is also meant to offer a larger contact patch than traditional sizing, closer in comparison to 29x2.4" mountain bike tires. Why they're not just using some of the many already available fast-rolling mountain bike tires, I don't know, but hey maybe I just don't understand innovation.

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The rim designation for 750d is 660, which is 38mm larger than 622 (700c/29"), which is 38mm larger than 584 (650b/27.5").

There isn't currently any production timeline for the 750d rims and tires, so availability will be limited for the time being. WTB says aftermarket availability is contingent on OEM adoption, so if and when the drop bar world moves to adopt the new standard we may see more of these larger hoops rolling around on the gravel roads we use to get to the actually fun part of cycling.

Author Info:
dariodigiulio avatar

Member since Dec 25, 2016
212 articles

252 Comments
  • 305 16
 MTBer: "The gravel segment couldn't possibly get any lamer." WTB: "Hold my beer."
  • 92 18
 Are gravel bikers just road biker converts? Who are these people?
  • 65 6
 @half-man-half-scab: I think they might be part of our clan but bored with suspension travel.
  • 43 7
 @half-man-half-scab: converts? more like heretics
  • 322 5
 @half-man-half-scab: I gravel and MTB. For me gravel is a great way to get in lots of training miles, before work rides, and rides from my house during the week. It's more of a replacement for a road bike than an MTB. I really hate getting into my car to ride my bike, and the closet decent MTB is a ~30 min drive from my house. I have access to ~60+ miles of excellent fire roads from my neighborhood, however. I love road biking, but drivers are so garbage that I'll probably never do it again.
  • 37 2
 @sngltrkmnd: 100%. With a healthy mix of 'good MTB'ers but not good enough to go world-level pro' and "retired" roadies looking for something that's still challenging but not as dangerous.

I like gravel bikes because they're efficient enough for the weeknight roadie group rides, perfect for weekend cyclocross in the fall, and ok enough to get you down some singletrack on those big weekend adventure rides. They've done a good job at turning 3 bike segments into one, a boon to wives and girlfriends everywhere.
  • 20 0
 @half-man-half-scab: My local trails close for 24 hours after rain due to the heavy clay soil. So my gravel bike comes on during those times to get away from roads with heavy traffic.
  • 7 5
 @half-man-half-scab: Gravel bike is great to have-for off season miles. .Nowhere near as fun to ride as a true road or mountain bike though.
  • 36 3
 @shreddyloam: Your last sentence.
  • 12 2
 @half-man-half-scab: roadies who are tired of riding on the road, see - cars. Scary AF watching them descend too...
  • 10 0
 @93EXCivic: This - I have a 'gravel bike' which is really just a road bike that is built for more comfort and capability when roads really suck... I'm in the Chicago suburbs, all the roads suck. Most of my "gravel" rides are mostly on beat up roads, sometimes dirt or gravel, when the trails are closed.
  • 5 8
 Roadies interpretation of "go big or go home" lol
  • 67 2
 @half-man-half-scab: Among us there is a faction who actually like the pedalling part of riding.
  • 8 55
flag rivercitycycles FL (Aug 28, 2023 at 10:21) (Below Threshold)
 @baca262: it’s just the Bike Industry’s me-too movement!
  • 8 5
 @half-man-half-scab: most are either roadies who don't want to risk their lives anymore or mountain bikers that ride hardtails or xc bikes. (which ironically are great gravel bikes)
  • 18 0
 @half-man-half-scab: People who don't live near any good mountain bike trails, but don't want to ride on the road with cars.
  • 4 0
 @half-man-half-scab: I ride my gravel bike a lot in the Northeast/Mid Atlantic because when it rains you can't ride a MTB or you will ruin the single track. That's how I got started, riding a road bike in those situations was not appealing.
  • 30 0
 @half-man-half-scab: I have enjoyed gravel a lot over the last couple years. Pure road riding is terrifying because people, and frankly not very peaceful. I also really enjoy the under-biking aspect of it. Rigid drop bars make otherwise boring trails that are closer to home fun.

Let people be weird and enjoy what they enjoy.
  • 4 3
 I mean overall those bikes make a lot of sense in their own niche but the hype kinda ruined the community. As a long range bike you can ride with big bags it's a good choice
  • 21 0
 @shreddyloam: You just encapsulated why I really want a gravel bike. I have a high-end (Well, it was high-end when I bought it in '09.) road bike sitting in my garage that hasn't been ridden in years. I've literally lost count of how many people have been killed on the roads around here in the past couple years, and I no longer have the race fitness required, nor the desire, to go out and hang at the local Tues. night world championships, so I don't need a "fast" bike for group road rides. I do kinda miss just grinding out miles on longer rides though. We have miles of easy fire/gravel road around here that's ideal for something that's not a full-on MTB. Those kind of roads are gonna be a lot more fun on something nimble and light like a gravel bike than my FS trailbike.

Gravel bike also seems to be a good platform for a bike-packing setup for family trips. With a 5yo, a 7yo, and a wife who is a beginner level mountain biker, we're not likely to be doing trips on the kind of terrain that would require a mountain bike. We've done some short trips and would like to do more of that kind of travel. For those reasons a gravel bike is next on my n+1 list.
  • 2 1
 @shreddyloam: gravel for the climb to avoid cars and roads for the down for that sweet-sweet descent.
  • 4 32
flag nickfranko (Aug 28, 2023 at 12:19) (Below Threshold)
 Gravel bikes are overstock road bikes that were inspired by Sam Pilgrim showing how durable a road bike was. Change my mind.
  • 9 0
 @shreddyloam: yeah there is no way I would put 12+ hour weeks on the bike if I only had a mountain bike, while I do have some singletrack very close to me I would get bored of riding it and the gravel bike is just more fun and way faster when riding on road to trails than a flatbar bike
  • 15 0
 @shreddyloam: Gravel bikes are also great to give life to those boring trails in the parks near home that I would never ride on a 150mm mtb. Going down a mild single track in the drops and with relatively skinny tires brings some fun back to life.
  • 3 0
 @powturn funniest comment I've read all month! Smile )
  • 1 0
 @half-man-half-scab: Yes, which explains everything!
  • 3 0
 @half-man-half-scab: I don't count myself as a "gravel biker" but I do own one, because at 6'5" and wanting a road (style) bike they're sooo much more comfortable than your roadie F1 tour racers. It's like driving my minivan vs. trying to fit into a sports car made for a 5'9" dude with a narrow ass.
  • 4 4
 Well, they succeeded with MTB, so why not find another bunch of suckers and repeat the history.
  • 2 0
 @lkubica: too many useable 700c wheels around
  • 11 6
 @shreddyloam: Road biking has to be one of the most dangerous sports out there. I used to do it to keep my legs and lungs strong while waiting for trails to melt in spring but after a few close calls with cars I had to stop. Every time I see a headline about a roadie being hit by a car I’m left wondering why people encourage this sport. We can take fault completely out of the equation and just acknowledge that tourist heavy, twisty mountain highways with narrow lanes, no shoulders, and limited view is no place for a bicycle. I live in aspen Colorado for reference. If gravel biking gets roadies off the busy roads and makes everyone safer, then I’m all for it.
  • 4 30
flag baca262 (Aug 28, 2023 at 14:30) (Below Threshold)
 @idontknowwhatiexpected: this. imagine the local law is that retarded that you're FORCED off the sidewalk onto the road if you're on a bike. a crash on a sidewalk will basically never be fatal, someone hits you with a car, you're a pancake AND they have to live with the fact they killed someone. also you're a nuisance to drivers. it's insanity, no one questioned it for decades.
  • 29 5
 @baca262: drivers are a nuisance to cyclists, they were there first. Not to mention cycling is a perfectly valid form of transport that shouldnt be discouraged by forcing riders onto slow, narrow shared pathways. If a driver can't avoid hitting things they really shouldn't be on the road.
  • 2 21
flag baca262 (Aug 28, 2023 at 15:08) (Below Threshold)
 @Murder-One: i see you're a quite the driver
  • 3 0
 @shreddyloam: if someone came out with a bike rack for a gravel bike, you could carry your mtb to the trail!
  • 3 0
 groadies
  • 6 0
 @Murder-One: I’m in that camp now that I have kids. I don’t want to get fat and if I only rode my enduro bike on worthy trails, I wouldn’t ride enough to stay happy or fit. My road bike permanently lives on the trainer now, my gravel bike is my daily driver for mixing road/fireroad, my XC bike is what I ride most days on singletrack, and the enduro bike comes out on the special occasions when it gets steep enough to be worth pedaling 35 lbs of bike around. Surprisingly, I enjoy riding as much now as I ever have. Lots of fun routes and races out there for the gravel and XC bikes.
  • 3 6
 @half-man-half-scab: roadies in denial of MTB actually being more fun
  • 3 0
 @baca262: change your name to Baka, so the name will check out
  • 4 17
flag nickfranko (Aug 28, 2023 at 16:35) (Below Threshold)
 @shreddyloam: so, basically you could just have a road bike.

Gravel bikers are the crossfitters of the cycling world. The comments and lack of sense of humor confirms this.
  • 13 0
 Gravel biking is to mountain biking as xc skiing is to downhill skiing: it makes tame, kind of boring trails scary and exciting because you have way less control.
  • 22 0
 I can't comment on the appeal specifically of gravel riding, but I can say something about road riding more broadly- and gravel is somewhere between the two. A huge part of the appeal is the activity starting the moment you get out of your house, as opposed to mountain biking, where most of us are faced with the absurdity of transporting a piece of transportation equipment to a special place so we can use it for its intended purpose. Also, in road riding it's a lot easier to zone out because you aren't constantly shifting your weight and all that, you just pedal and shift gears and that's it. I love mountain biking, but my preference has swung between it and road riding many times over the past nearly three decades of my riding.
  • 5 6
 Gravel bikes are XC bikes for people with bike handling skills...
  • 1 1
 @pbullard2017: Exactly, so why the need for another wheel standard? Sell more bikes as the consumer products market enters a slump! This will do wonders for the resell market.
  • 2 0
 @half-man-half-scab: I've been mt biking since the 80's and I love my MTB, gravel and road bike. On hot summer days in Southern California the weapon of choice is the gravel bike. Lighter weight for those 2-3000 ft climbs. Pinning fire road descents is a lot of fun. I'm not as blown out the next day to ride my MTB bike on those same climbs. + I start my ride from home, no need to drive to the trailhead.
  • 4 0
 @SoCalTrev: "The local Tues. night world championships..." That made me lol.
  • 6 0
 @shreddyloam: Good comment. Despite having a trail/AM bike and a DH rig and despite being 100% a mountain biker at heart - my gravel bike might get used the most just because I can ride it straight from the door. If I only have an hour after work I can ride straight out and make the most of that hour. It's also something I can do with my girlfriend - gravel riding is way lower barrier to entry than MTB.

Regarding the 750 rims - if you guys have ever seen a size XL or size 60/61/62cm gravel bike the 700 wheels look tiny on there. Much like an XL 27.5 MTB can look.
  • 2 0
 @plume: they should ban protective pads from Enduro and DH racers then we can see who's really brave.
  • 3 1
 @shreddyloam: I do similar, as I commute and ride local fire roads and trails on the way home. But that I use a 29er hartail for. I just don't see the point of buying a gravel bike - why would it be any better than an XC bike?
  • 7 0
 We are all just riding bikes, why cant we all just get along?

Bahahahahaha
Sigh
  • 4 1
 @saladdodger: it makes easier trails far more exciting. a lot of the trails in the foothills around here in Utah are pretty smooth. The occasional rock garden in the drops is EXCITING where my all mountain bike would otherwise feel bored. Try it. You may just find you like it. Or don't; I don't care.
  • 4 0
 @skiwenric: no I have to be personally offended that someone enjoys a riding different type of bike than i do.
  • 2 0
 @half-man-half-scab: The roads are too dangerous. Riders are hit by cars a lot more than people realize. The marketers ruin everything. Most gravel riders are roadies who want a safe place to ride.
  • 1 0
 @TET1: I'm sure every town with an active cycling community has something similar. Those group training rides that are fast-paced, competitive, and geared toward the local racing crowd, and that some people take way too seriously. It was actually good fun when I was fit enough to be trading pulls and bridging gaps at the front. Less so now when I'd likely be spit out the back on the first climb...
  • 4 1
 @saladdodger: XC bikes are good for one thing and gravel bikes are good for another. If you went on a ride that was 70% road and 30% off road (I do this all the time), a carbon gravel bike with drop handlebars, fully rigid fork and with 2x11 gears is a lot better than an XC bike. It's barely slower on the road than a road bike (and if you change the tires - it is a road bike).

If the ride was 30% road and 70% off road (including some small drops and jumps etc) suddenly an XC bike would be way better.
  • 1 1
 I tried the gravel thing, I didn't like it. For me it is the worst of road riding and the worst of dirt riding. So I put skinny slicks on my gravel bike and use it for commuting (daily 2+ hours round trip). But, I get why people like it, just not for me. Same thing as CX racing, just not for me. I will probably be ordering a new roadie next week though, so that will make me happy.


@TET1: The "World Champs" scene in SoCal is huge. I don't know about other place, but I know of a "Worlds" every Tuesday night, and two crit races in pedal range on Thursday night. A dude I know does one on in a rich neighborhood every Wednesday at lunch, and another guy I know does one Wednesday mornings. These are all treated as races, not fast group rides. And you will likely find some pretty fast people, as in actual national pros attending. I haven't gone in a long time since I haven't been interested in socializing (I'm very introverted).
  • 3 0
 @JSTootell: I'm going to start group rides where the goal is to go as slow as possible without falling over.
  • 1 0
 @TET1: I think that is called "trials".

Would be fun to see that in group ride format.
  • 1 0
 @JSTootell: Not trials, just two wheels on the ground at all time, creeping along in the neighborhoods. In order to not be disqualified you have to at least be moving at all times, with your two wheels on the ground.
  • 1 0
 @TET1: A bike crawl. Those also happen in most mid-size to major cities. They're a lot of fun with zero fitness required.
  • 1 0
 @JSTootell: Sort of, but Trials does have a (maximum) time limit. This would be a "slow race", something like this:

www.youtube.com/watch?v=CB9lf9BqgmQ
  • 2 0
 @half-man-half-scab: nah. Most mtbers who try gravel end up throwing road tires on the gravel rig and use a xc bike for the smaller stuff. Gets too sad passing all the single track from the fire roads. For me anyways
  • 3 1
 @rivercitycycles: You're not the first to make idiotic MRA comments, but you're the only one doing it with your business handle. Might want to delete your account before the rest of Portland finds out.
  • 1 2
 @fentoncrackshell: why do people keep thinking I’m associated with that shop? How many other cities in the USA have more than one river running through it? I have an opinion just like the next user.
  • 1 3
 omfg look at the sheer, violent amount of entitled pricks here. don't worry, reality checks are in the mail
  • 1 0
 @LAbikerider: I imagine it depends on where you live. The local spots where I ride, either I am riding there cause the trails are closed from rain so it doesn't make me sad to pass them or there is a big local loop but there is no singletrack attached it to.
  • 1 0
 @half-man-half-scab: would be roadies who watch van life vloggers on YouTube
  • 1 1
 @rivercitycycles: Why? I'd guess it's because it's a big, famous bike shop. Why is that not obvious to you? Do you think beer book author Michael Jackson wondered why people had heard his name elsewhere before too?
  • 1 2
 @barp: I’ve learned not to make assumptions but you’re free to assume!
  • 1 1
 @rivercitycycles: You're assuming that I'm free to assume right now.
  • 2 0
 @sngltrkmnd: bored with suspension does not exist as a sentence.....
  • 1 0
 @shreddyloam: Holy shit dude are we the same person?!!? LOL You describe my experiences 100% I'd just add that I like being able to hit train track byways and dirt roads at will where I might hesitate on my road bike.
  • 86 5
 This whole comment section will be a copy/paste of the first 29er article
  • 109 0
 But 38mm bigger.
  • 5 6
 @pipm1: you win lol
  • 8 16
flag nickfranko (Aug 28, 2023 at 12:18) (Below Threshold)
 The first 29er was on a bike with travel. Not an overstock road bike that they somehow convinced people was a different riding segment.
  • 9 1
 @nickfranko: gravel bikes are what we call the original "mountain bikes" now-a-days. They're not copies of modern road bikes, they're almost identical to the bikes we smashed down the north shore on before your one buddy showed up with a wildly expensive suspension fork bolted on to his and everything changed.
  • 9 0
 @nickfranko: Actually....no, the OG was a 700c (ie: 29") roadbike wheel..
  • 1 0
 I was thinking exactly this.
  • 1 2
 Except 29'ers (which I didn't like the way they rode when they first came out) were trying to make mountain bikes more capable. Gravel bikes are making them less!


Gravel bike filter please, PB! Smile
  • 1 0
 I copied and pasted my comment from back then! You'll be able to tell I'm a time traveler if you find it
  • 44 1
 I got to see this bike in the flesh yesterday at MADE and I spent some time talking to Moots about why they're experimenting with this. Here's the gist of their "why":

- It's still an experiment and may evolve into something different.

- The reason they aren't just using a larger MTB/Gravel tire pertains to aerodynamics, ride quality, and contact area: Moots says that a 40c 750D tire effectively has the contact area of a larger 48-52mm 650B tire, but in a longer and narrower contact patch. They say this is more aerodynamic for the same level of float, and the ride quality at higher speeds is better/more controllable than 650B in their experiments so far.

- Part of their initial prompt to explore wheel sizing was with difficulties optimizing the range of 1x drivetrains for gravel riding around a desired speed range and tire size, and the larger wheel size helps them optimize a gear range for the desired speed range with a desired tire size, while also claiming the benefits above.

- They see this tire optimized for a certain speed range. They said that generally for gravel, they see 650B as a 14-18 mph tire, 700C as a 15-25 mph tire, and 750D as a 17-30 mph tire.

- Because of the speed range, It's ultimately optimized for racing or higher speed riding.
  • 17 9
 Gravel bikes and aerodynamics? Won't the difference be negliable?

Though I see it as a useful standard for those long travel expedition setups. The issue is you won't find replacement tires if you have issues.
  • 26 1
 @spaced: when you consider the average speed of most gravel racers aero is very important
  • 24 0
 Can someone explain the gear range thing?

Did they develop a new wheel size rather than changing a chainring on their existing bike?
  • 5 1
 I'd like to see some data to back up the "longer contact patch is faster" idea. These with a 40c tire have a similar diameter to a 2.1" 29er tire, and wheel+tire probably has a similar weight.

I thought these days we all believed that fat tires at lower pressures were actually faster on rough terrain. Is it really faster than the 29er setup in anything but really high speeds due to aero differences?
  • 10 0
 @spaced: Depends where you're riding. Out in the US where there's gravel roads that go on for miles and miles across plains aero would definitely make a big difference. Here in Britishland it would make no difference riding along the towpaths and forest trails.
  • 2 0
 @Fix-the-Spade: yeah but when your riding on the road to the trails aero matters a lot, not everywhere in the US is Kansas with miles of flat gravel, a lot of US gravel riding is closer to British gravel riding but drier with a mix of roads, fire roads and singletrack.
  • 2 1
 And the bike is just beautiful.
  • 1 0
 Please explain what the "c" is supposed to mean in the term "40c" that you used? And I don't mean to pick on you; it's actually embossed on the damn prototype tire in the photos. I believe it's just confused continuation of the nomenclature of 700C tires.
  • 3 0
 @Drew-O: Agree. I always thought shorter/wider contact patches were faster.

Perhaps longer contact patches engage more gravel tired-sized block knobs, and therefore grip better and let the rider corner faster.
  • 1 0
 @spaced: recent 300 mile race was won by a guy averaging 250 watts for 10 hours. Aero is huge in gravel racing!
  • 5 0
 @somebody-else: 30 mph for 10 hours? I’m not so sure…
  • 3 0
 @pmhobson: yeah brain fart on that one. 8hrs for the 150 mile and 18:34 for the 300 (250W avg).
  • 2 0
 @Drew-O: longer contact patch is not directly faster, but it does give you same patch area with a slimmer tire, which has a lower CdA.
  • 3 0
 @barp: This is a long dumb and answer for a long dumb topic, and I probably have some of the facts wrong BUT: My understanding is that the letter designations are from an old French system that was supposed to allow for similar total wheel diameter with different tire sizes. So "700" was the approximate outside tire diameter, and there were "700a, 700b, 700c" etc ranging from a skinny tire w. larger rim to a fatter tire w. smaller rim. The other "700" sizes have died out, so pretty much all road rims are now "700c". Use of "c" with tires is probably a shorthand for "fits 700c rims," though I agree that in this case it seems nonsensical, since the rim in question is a 750D designation. The whole system is confusing as hell, as the named "standards" have no basis is reality (700c just means 622mm bead, 650b means 584mm, both are interchangeable with 29er or 27.5, road tire diameters are usually in mm while MTB are inches.) BUT, "c" on the end of a number is understood to mean tire diameter in mm for road/gravel tires, and given that the whole system makes no sense efforts to correct that are futile.
  • 3 0
 @Drew-O: Exactly. Almost nobody understands the French size naming conventions any more, but because 700C was the most successful of those sizes (as a bead seat diameter, that is--because the letter designation indicates the width of the tire for a given inflated diameter, which in this case is 700 mm, an actual 700C tire is exactly an ISO 622 - 39 and any other width with the same BSD is not strictly a "C"), people have started to assume that they need to suffix all tire widths with "C" without really understanding what that letter's supposed to mean. It does not stand for centimeters (the BSD and nominal cross-sectional width are both given in millimeters) or anything else.

Sure would be easier if we'd all use ISO tire size names. I watched a coworker struggle with a 26 x 1 3/8" tire just the other day. He needed ISO 590 and was trying to fit a 597 (almost exploding the tube in the process). I'd blame it all on the US's failure to convert to the metric system, but you've still got Continental and Schwalbe in Germany calling their tires 28-inch.
  • 4 0
 @barp: I’ve even seen tire companies refer to a 650b x 47 mm tire as being 47C wide and it drives me crazy and YES this is a hill I will DIE on
  • 1 0
 I mean, the whole system of nomenclature should be nuked from orbit and rebuilt from scratch, as should BB standards, free hub body standards, headset bearing standards....what am I missing?

The immediate and violent backlash against this new wheel standard gives me some hope, TBH.
  • 1 0
 @pmhobson: It depends largely on the tread pattern. On a tire with a smooth center, the longer contact patch will create even lower rolling resistance.

Contact patch science assumes that the tire is a slick but that theory doesn't work for treaded tires.
  • 1 0
 @pmhobson: You and I both, buddy.
  • 1 0
 @Drew-O: I agree with you.

Unfortunately, as we all know, this is what will happen whenever standards are "nuked"

xkcd.com/927
  • 2 1
 @bogey: Good info. N.B. My original comment about contact patches should have said that shorter contact patches have *lower rolling resistance*. If even that’s true in the slick tire case(I’m not sure), that won’t necessarily result in being faster.
  • 31 1
 Yes! The only thing I'm disappointed about is the lack of new hub standard. Surely this needs like super super boosted boost width hubs to truly do it justice.

You'll find me at the trail head this weekend saying something like: "No, blacks for me today. I'd die on this 29er I'd need at least 750c wheels to ride that"
  • 10 0
 You'll need the d if your going to ride that hard.
  • 5 0
 You joke, but road/gravel currently use non-boost through axle hubs. I'd bet some brands will move to gravel-boost (with 12x110 front hubs rather than 15x110 like MTB, just to be ornery!) in the next few years. This may make sense for improved tire clearance but will certainly piss everyone off.
  • 2 0
 @Drew-O: Way ahead of you. The Salsa Cutthroat uses Boost spacing already.
  • 1 0
 @barp: Salsa also uses Super Boost on all their MTB's, including their XC Spearfish. That company likes to be ridiculous when it comes to hub spacing.

And tbf, the Cutthroat is basically a hardtail with (very wide and flared) drop bars. It's marketed towards folks who are swapping their MTB wheels onto it for 2-week long bikepacking adventures.
  • 3 0
 @barp: yes, road boost already exists in 12x110 & 12x148. Quite a few companies use this already especially in the road/gravel e-bike world. It's completely unnecessary to go boost for road and gravel and even more unnecessary not to stick with 15X110 if they insist on boost.
  • 24 0
 WHY go with another stupid, nonsensical, outdated, name?

650B actually meant 650 outer diameter and a 32mm tire height, which got pretty close to the ETRTO Bead Seat Diameter of 589, but using the B for MTB tires was just stupid, because they're all closer to 60mm in height/width.
700C was the same idea with 700mm outer diameter and a 39mm tire height, which again is pretty close to the 622mm BSD of road wheel and 29ers, but the actual C height/width is only just now being used on road bikes.
750D should mean an outer _tire_ diameter of 750mm and close to 45mm of tire _height_, which does get close to the BSD of 660, and will probably represent a fairly common actual tire height/width, but it still adds the complication of 750 not always being the actual tire diameter and D not always being the actual tire width.

AND, we don't call 29ers "700C", because that would be stupid, and it's why 650B nomenclature faded away. Despite 27.5 being also stupid because, given the same tire height/width, it's exactly 1 inch bigger in diameter than 26, not 1.5 inches bigger; though it is 1.5 inches smaller than 29, which maybe should have been called 28.5...

It should have been named by it's BSD. 660 has a nice ring to it, and with more manufacturers displaying the ETRTO metrics more prominently, it becomes obvious which wheels are bigger. "40 x 750" is just dumb, and actually wrong if that tire is really 40mm high: outer diameter will be 740 in that case, not 750.
  • 8 2
 Maybe they didn't choose that because it just took you half an hour to explain it?
  • 2 0
 @CheddarJack46: umm, what took so long is when I explained why it's wrong: where the name they chose came from, and how their usage doesn't match the original intention of the naming. The one they should have chosen is one sentence: "Should have been named by BSD."
  • 5 0
 @CheddarJack46: Maybe just call the diameters by they ... size?
559
584
622
660

Sorry if this is a nerdistic view... But I find elegance in simplicity

Quite many times I've had people ask my the difference between ' 28" city tyre ' and ' 29" mtb tyre ' for example
  • 21 0
 I would love to see 29 x 2.2 become more prevalent in gravel before this. Totally understand the purpose behind it, and I don't hate it, but there is lower-hanging fruit that we could benefit from.
  • 3 0
 I run 29x2.1. Pretty limited selection unfortunately and I really wish there were more tougher casing options, but it gets the job done on pretty much anything I ride on.
  • 2 0
 Loving all the new gravel going 50x700c Only true gravel bike that would fit 2.2 is the lauf, all others are more like a bikepacking like the cutty etc.
  • 2 2
 @adrennan: yeah great stuff! I wish they gave a flat bar option on gravel bikes so it would be easier to navigate rougher terrain. Now that would be some innovation!
  • 1 0
 700c is the same diameter as 29 so you can use MTB tyres on 700c rims (I do it on my gravel)
  • 2 0
 @adrennan: Just run a Cushcore without a tire.
  • 16 1
 This (and 32") is a Shaq wheel size.

Ie., if you're as tall as Shaq, make as much money as Shaq, and want bespoke everything like Shaq, then this is for you. All us normal plebs need not apply.
  • 3 0
 Shaq has enough money to buy WTB, probably e*thirteen and ENVE for good measure and make them produce whatever the hell he wants...just ask The General or Papa John
  • 1 0
 31.4"
  • 1 0
 I forgot the guys name, he does a lot of local racing in my area, but a retired pro basketball player who makes his XL XC bike look pretty tiny. And he is short for a basketball player.
  • 1 0
 @JSTootell: Reggie Miller?
  • 1 0
 double post
  • 20 3
 Can anyone say toe overlap? Saw this on another site a couple days ago and it made my bones hurt thinking about it.
  • 12 3
 I believe these are generally aimed at taller riders (like myself) for whom this will not be an issue.
  • 9 4
 @sngltrkmnd: Weird, as a taller rider I also have bigger feet, which makes toe overlap more of a problem, not less.
  • 1 1
 @igxqrrl: Not to mention generally longer cranks for taller riders.
  • 5 0
 @igxqrrl:
Most bikes in the 'progressive' side of the gravel spectrum are growing in terms of reach, bringing stems shorter and meaning no toe overlap (I challenge to get toe overlap on the new Stig, however big your feet are). That said, where do we draw the line between mountain bikes and gravel? Oh yeah, with stupid new wheel sizes. No thanks.
  • 3 1
 First thing i saw. Im 6’1” with 12.5 feet and my tcx with a 47mm tire up front i toe scrub…f*cking hell she would be dicey on that unit. Needs to be longer, slacker…. Like the chamois Hagar
  • 1 0
 @solarplex:
I mean yeah, the TCX is a cross bike, of course you're getting toe overlap
  • 1 0
 @igxqrrl: But you also (presumably) rider a larger, longer bike with a longer front-center. And don't ride with the heel of your foot centered on your pedal. But sure, if you want to hate 750D, I'm not gonna stop you.
  • 1 0
 Where and when does this “toe overlap” ever become a thing? To turn your bars that far without crashing you must be at a standstill, correct?
  • 1 0
 @FuzzyL: My giant TCR size ML certainly has toe overlap, which is a bit sketchy track standing at traffic lights on the commute, or just at road junctions on a "proper"ride. And it's really bad with mud guards in winter, which is a market for gravel bikes. I use MTB SPDs, which are quick to jump out of if I get it wrong. Road cleats would be less fun
  • 1 0
 @sngltrkmnd: also road bikes are stupidly short thanks to uci ruling. So I think overlap should be less of an issue for gravel bikes if the manufacturer isn't hung up on road geometry
  • 1 0
 @FuzzyL: You can get toe overlap at, maybe, up to 10kmh. Hairpin corners, U-turns, navigating tight areas on city paths. On a gravel bike you might be doing some steep climb and get toe overlap on a tight corner or even navigating around rocks uphill.
  • 1 0
 @WheelNut: Actually, I was riding a track bike in the city about 30 years ago, when that was fashionable. With the vertical head angle on a relatively small frame for my size that thing had a bit of toe overlap (I don’t think it actually matters if a bike has a little or very much overlap, if the wheel strikes your foot it strikes your foot). I never had any issues with it.

Of course it can happen in a handful situations in which you are going very slow or are track standing. But I think it’s relevance is blown way out of proportion. It’s like complaining about the reduced steering angle of a double crown fork. Yes, that too can become an issue, but it very very rarely does.
  • 2 0
 @FuzzyL: I believe the amount of overlap does matter: With a minimal overlap, your toe can strike the tire only when your pedal is all the way forward; with a ton of overlap, there's a wider arc of the pedal where a strike can occur. More angle/time of overlap means more chances of a strike.
  • 11 0
 Because why offer better tires for an existing larger size such as 32 or 36 inch, when you can invent a pointless new wheel size to do the same thing. 36ers use a 787 ISO bead number and 32ers use 686 ISO, and in fact you can already buy production 32 inch tire mountain and hybrid bikes in China. There's also 700A at 642 and 700B at 635 which again, in a 40mm width would provide more casing size and air volume than a 700C x 40 would.
  • 10 0
 "meant to offer a larger contact patch than traditional sizing"

It's not larger, just longer and skinnier. Pressure is pressure, it doesn't care how big the circle is. The same PSI will give the same square inches of contact per pounds. So unless you're lowering pressure or gaining weight when changing wheel sizes, the contact patch won't be larger.
  • 1 0
 Not an engineer here but super curious. Will you explain this in further detail like you're talking to a room full of idiots(me)?
  • 3 0
 @TET1: force = pressure x area. For a given force (read systemweight here) and pressure the area (read contact patch) is also the same for all tires, just the shape is different. A wider tire will have a rounder shorter contact patch, a skinnier tire with a bigger diameter will habe a more ovalized longer contact patch, but the area is going to be the same.
  • 3 0
 However some truth as some of the contact patch is from carcass rigidity. There is less tyre deformation for the same contact patch.
  • 3 0
 @Tristanssid: that should be negligible when loaded with a rider.
  • 2 0
 @Tristanssid: that sounds like it will take less pressure to get the same patch, since the carcass is acting like some extra pressure. So same pressure, less deformation (from bigger diameter and more carcass involved), equals smaller contact patch...
  • 2 0
 @justinfoil: I did write my example poorly. The carcasses would be similar in rigidity but the amount of deformation is related to the air pressure and the carcass rigidity, as the tyre deformation from carcass rigidity is about the same a bigger contact patch occurs. How much difference is directly related to the carcass stiffness, a DH tyre would see a larger patch increase than a paper thin XC tyre that mostly relies on air pressure. In advertising bigger contact patch could be 0.0001%
  • 12 0
 I've been dying for a way to make my Moots gravel bike more unique and expensive, thanks WTB!
  • 7 0
 I don't hate it, but wish they would have just named it by the BSD instead of grafting onto the inexplicable French naming system.
  • 7 0
 Wow , a full 5 days after this broke on other sites.... I guess its in order to make room for all the moto/ebike contents :-)
  • 6 0
 We need a volunteer to take this 30.5in bike down A line. And then go super mullet 30.5in front x 26in rear. We can now make a penny farthing DH bike for Sam Pilgrim
  • 2 0
 I'd give that a like + subscribe
  • 4 0
 Put 'em on the "ebike" class of motorcycles, and fugedaboudum. BTW..., howcum nobody ever compares the contact patch of all these rehashed old ideas, with some of the other rehashed old ideas, like 26ers, 28s, or the other seldom mentioned 36ers? Are those "old" now? Her's a new rehashed old idea! Make 'em new again & sell 'em to the really new rehashed NEW riders! Sell 'em at premium prices to the nouveau riches daddies looking for a reason to spend more on less, by bestowing a specific tire size on the custom framed topshelf kitted teeny bikes that their kids are using in the back yard, to learn how to balance & turn!! There should be a special size tire for that!! A 26.5X7" BUMPY LAWN TIRE!!!
  • 4 0
 Makes sense to me.
700c on 63cm and larger looks like an out of proportion clown car.
Correct the trail and move to proper chain stay length for the biggies.
Perfect OE application is the KHS Flite 747 (a Leonard Zinn derived bike).
That has 200mm cranks and the larger hoops really would be mathematically correct.
If there is a market it will catch fire - then get reflected in the larger OE world.
We’re talking custom frames for people used to buying special due to their circumstances.

I’ve got a GT Tachyon w/ the D size wheels.
That one sorta flopped.
  • 8 1
 Toe overlap, more like ankle overlap.
  • 4 1
 I mean... it was bound to happen eventually, and gravel is probably where it makes the most sense.

It would be cool to see someone build a test frame with interchangeable dropouts to go between all three wheel sizes (assuming WTB offers the same tires in all sizes) and compare efficiency & comfort on various surfaces. I'd imagine these spin up super slow, but if they're a bit more efficient, it might be worth the trade-off.

In order to keep these from feeling sluggish, they'll need to keep the rim/tire weight down. However, if they try to use standard dropout spacing, I bet they'll end up with a lot of lateral flex, be hard to keep true, and break spokes faster than the typical 700c.
  • 3 10
flag Whataboutism FL (Aug 28, 2023 at 10:57) (Below Threshold)
 Gravel≠mtb
Side note. So Levy is gone? Seems like a really long vaca…
  • 8 1
 I don't trust anybody who uses alloy nipples.
  • 4 0
 I understand the durability of brass, but why not color coordinate when you're going to be relacing to a new wheel size every few years?
  • 4 0
 As the winning commenter pointed out on our 750d announcement last week (shameless plug), they shoulda went with the 666 ETRTO ... missed by 6mm: bikepacking.com/news/wtb-moots-750d-wheel-size/#comment-6263089803
  • 3 0
 I want to rail against this under the good 'ol "... not ANOTHER new -insert data- #*$&ing standard!!" section but history tempers that. When 29" bikes where coming on scene I was against it, granted most handled like a bag of bricks. Geo got sorted, the industry adopted it, now we're blessed with a uni-wheel size superior to 26" in pretty much every way.
Just saying maybe lets wait & see what sticks, maybe it's dope.
  • 3 0
 When they say "size" of the contact patch in the article, I think of area. But the area is the same, the shape will be more elongated, which I would call 'longer' rather than 'larger'
  • 4 0
 Yes yes, time to annoy a different segment of cycling with this kind of bullshit! I vote 13 mm axles and 28.99 mm crank spindles!
  • 6 1
 This can't be a legit gravel article. Neither "grinder" or "Roubaix" were used
  • 6 0
 Oh perfect just what no one asked for
  • 4 1
 I've built plenty of road and gravel bikes for really tall people and this would be fantastic if it catches on.

Hell, I'd build some mountain bikes with 31-32" wheels if they did a decent tire.

Good on ya, WTB.
  • 1 0
 It was about time. The only non standard thing recently I thought was super boost.
We were so close to having really nice standards across most lines; boost on a mtb, 12mm axles, we needed something to shake things up I guess.
Custom frame builders must also be pumped.
I'll keep riding my 2018 diverge for now though Smile
  • 1 3
 Tis true, 32" and 36" already exist ...

A few years back I was riding 32" on a mountain uni, I broke down a Walmart cruiser bike to scavenge the rims/tires, it made a great XC wheel size, glad it finally caught on.

That said, this is a new standard we don't need.
  • 1 0
 most say they ride gravel to stay off the roads from crazy drivers. but then i hear about gravel riders getting chased down by crazy "out there in the sticks drivers" on gravel roads with no shoulder and no easy way to stop..
  • 1 0
 What I find funny is the popularity of 27.5/650b in gravel, when we've already learned through MTB that bigger wheels are better over rough terrain - so 700c/29 would surely make more sense? How much real terms difference can there be between this and 29??
  • 1 0
 As a tall guy who likes normal looking bikes (no freakish long headtube), I like this. As I understand, the gravel tire on this rim has the same diameter as a 2.4" tire on a 700C / 29" rim ... so in a sense, it's not a new standard - it's just bringing true 29" size to narrower tires / gravel.
  • 3 0
 WTB: *Introduces new standard*
Also WTB: "but it's the SAME OD as a 29er MTB wheel and tire, so it's really the same"

Excuse me while I jump off a bridge.
  • 1 0
 Laugh all you want. WTB is largely responsible for the "29er" mountain bikes most of use ride today. The outer diameter of a 29" rim with 2.4" tires is going to be pretty close to the O.D. of one of these 750d rims with a narrower "gravel" (i.e. cyclocross, touring, town) tire. Makes a heck of alot more sense than a 6'6" dude riding 26" wheels.
  • 1 0
 Don't get me wrong, I'm of the opinion that this unequivocally stupid, but: We probably won't have to endure the same growing pains as back when the industry collectively started switching to 29" as the predominant wheelsize. Back then, they had no idea how to make bikes with big wheels fun and capable, but nowadays they understand a lot more about frame geometry and they can rely on the experiece they gathered figuring out 29ers. I'm definitley not at all in favour of yet another pointless change in standards but at least, should it happen, it won't be as bad as it was with 29ers.
  • 2 0
 since it appears to be strictly custom, these wheels should probably use the supa fat hub standard for better triangulation, 150/197
  • 2 0
 You've got it all wrong. It needs to be 140/187.
  • 10 6
 If someone rode gravel and didn't post about it did it really happen?
  • 3 0
 I guess on the bright side, 58 and 60 cm frames will not look so goofy anymore.
  • 3 1
 how many rides until the rims crack at the eyelets ? wtb = will totally break (and by break i mean the rims will crack at the eyelets)
  • 2 0
 36" and 32" Mullet is the future for Roadcycling!. Longer Toptubes shorter stems - doesn't that sound like a new idea?
  • 3 0
 What's todays date? Oh, thought I've been a sleep for 7 months.
  • 3 0
 It’s the innovation that’ll launch a thousand GCN youtube vids
  • 1 0
 Wouldn't road bikes have benefitted from this..? Is there a reason that it hasn't happened there? Or has it and I just know nothing about road biking?
  • 2 0
 This is exactly what we need
  • 2 0
 Can you say mullet-gravel?
  • 4 1
 Gtfo
  • 1 0
 Has anyone thought of using this 750D rim with 2.4 MTB tires to have a wheel bigger than 30"?
  • 2 0
 30 inch! 30 inch! 30 inch! we want 30 inch!
  • 2 0
 but... now i need longer spokes!?
  • 2 0
 Fuck ya, a new wheel size.
  • 1 0
 650b helped to sell lots of new bikes and make your old one outdated, why not try it with 750 too?
  • 3 0
 Sup 29er panzies
  • 2 0
 Big Gulps huh? Alright! Welp, see ya later.
  • 2 1
 nope, no, negative, don't need. still wondering what was wrong with 26" wheels.
  • 1 0
 Someone wanting to re-invent the wheel
  • 1 0
 Ok.... we dont need another wheel size WTB. Please keep ur crazy dreems for yourself.
  • 1 0
 why not throw a new bb, new hub width, new headset type, new chainring, new seatpost diameter into the mix
  • 1 1
 This is not a bad thing, but it does complicate tire options and inventory even further. I doubt it will stick, as even 650b is dying, except for XS frames.
  • 1 0
 Does this mean there's gonna be a new wider WTB front and rear hub standard? This is getting f*ckin stupid!
  • 4 2
 :ermagherd:
  • 2 0
 Bring the heat!
  • 2 0
 Kill it with fire!
  • 1 0
 Calling all butt pad manufactures
  • 1 0
 Waiting for GMBN to try and retrofit this onto a MTB
  • 5 6
 The rim designation for 750d is 660, which is 38mm larger than 622 (700c/29"), which is 38mm larger than 584 (650b/27.5").

WTAF is this.
  • 2 2
 Wondering the same thing.
  • 2 0
 750b bsd is 76mm larger than 650b bsd. There.
  • 2 2
 Yeah I'm a little confused. Is it a 30.5"?
  • 7 1
 False equivalency logic. 650B didn't replace 26 inch because it was 38mm larger ISO (it isn't), but because it was an existing established tire/rim size already adopted by folks in the loaded touring/bikepacking communities, and that had historical ties to mountain bike, and because the original "modern" 650B mountain bike tires were approximately 27.5 inches in diameter, it felt neatly in between 26ers and 29ers. It was easy for Kirk Pacenti to have Vuelta USA roll him wider rims in that size and Panaracer to make him tires once he ponied up the money to order 500 of each to do a production run, and that was enough to get a grassroots movement embracing the size again as many disc brake equipped 26ers could be converted for folks, including brand managers to test the size out. Similarly 32 inch unicycle tires have been adopted already by companies wanting to make larger fitting sizes of mountain bikes, and this has also led to an increase in manufacturing for the tire size (686 ISO) and in China today you can buy production 32 inch mountain bikes.
  • 2 1
 @shakabro: It would be smaller than 32 inch (which is a 2.1 inch tire width on a 686 ISO rim). Simply producing a 1.6 inch width tire for the same existing rim size would achieve a similar diameter to a 29 x 2.4. 750D is a solution in search of a problem.
  • 4 3
 Outrage now, everyone riding 31ers later.
26” for life!
  • 2 0
 26er ain't dead.. they have 36er wheels already
  • 4 2
 Just say no.
  • 1 0
 Here me out 29r mullet. It'll be all the rage in 2025
  • 1 0
 This is the Minka of wheel standards.
  • 2 0
 Just end it
  • 2 1
 At what point do gravel bikes just become mountain bikes?
  • 2 2
 0 difference between modern gravel bikes and 90's mountain bikes besides wheel size
  • 4 0
 ...and handlebars and disc brakes and drivetrains with clutches and thru axles and good tires...
  • 1 0
 @VtVolk: You can still put all that you mentioned onto a good 90's MTB bike frame and make it into a "gravel" road bike.
  • 1 0
 @CSharp: You can take a good look at a T-bone by sticking your head up a bull's ass, but wouldn't you rather take the butcher's word for it?

And if you're old enough to recognize that quote, you should also know that the vast majority of 90s mountain bikes didn't have thru axles or any way to mount disk brakes. Sure you can slap some curly bars, skinny tires, or even a clutch derailleur on one, but I don't know why anyone would, especially if the goal is actually riding gravel and/or roads.
  • 1 0
 @VtVolk: Dude, you can get a 9mm and 10mm thru-axles like the ones from DT-Swiss. As well, you can get 10 and 11-spd derailleurs with clutch. And you can convert those 90's bike with good steel or aluminum frames. If you really want disc brakes, you can get the IS or post mount brazed on. For this, I'm the butcher. So, don't stick your head up the the wrong ass!
  • 1 0
 SO.... closer to true 27.5" an not 27...........
  • 1 0
 Nobody cares, its Gravel, move on to the MTB content.
  • 1 0
 DeKerf is welding a frame as we speak for MTB
  • 1 0
 I've actually seen something like this in the wild.
  • 1 0
 I don't doubt it. There was a batch of eccentric bb steel frame and forks made in 1999 along with the rims and 40c Nano's that got passed around under embargo. Takes awhile for some things to perc? Covid did kind of get in the way of things eh? Not as significant as the 52/47 700c Nano back in 99', which raised a similar uproar IIRC, nor will be but just another couple of sku's for some folks that could benefit from it perhaps? Ride well on good gravel but wish they had made the rim i30 and the "tire" 45c personally for the chunkier stuff we have here in the PNW at times as well as cross compatibility to MTB. If you really want to hate mine has a 1000w direct drive front hub motor and a Schlumpf High Speed drive so when I'm ripping along at over 30mph I have plenty of pedal power.
  • 1 0
 Just fkn’ build a monowheel already.. 6025bbc.. then we’d all be happy
  • 1 0
 This gravel bike thing is generating a lot of initerest! Take notes PB
  • 1 0
 whens the new P series 750D drop?
  • 1 1
 Way much More biggest wheel standards is lovely for sure but what I really wanna know is what does Wes Willits think?
  • 1 0
 Wes “Willits” Williams
  • 1 0
 I am 110% in favor of this development for gravel bikes.
  • 5 6
 Are those washboard gravel roads beating you up? (boo hoo)

Then ride on the road, or get a mountain bike.
  • 4 4
 should be posted under sadanduseless
  • 1 0
 that last sentence haha
  • 3 3
 the pea gravel riders will be frothing over this ridiculous wheelset size
  • 1 0
 WGAF.
  • 1 0
 So it's 30.5" ?
  • 1 1
 YAAAAAAAAAAAAAAAWWWWWWWWWNNNNNNNNNN!
  • 1 0
 Uggggghhhh... Again?
  • 1 0
 29" ain't dead!!
  • 1 0
 Neither is the 26'er
  • 1 0
 "D, it's the biggest".
  • 1 0
 Date check.
  • 1 0
 650b was way more silly
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