700x40 or 27.5x2.00
 

Which one would you choose for general commuting? It would include cracked roads and shortcuts on grass, dirt roads or trails.

700x40 would be my choice, and it would be a fast-rolling "gravel" tire like the Pirelli Cinturato Gravel H or Schwalbe G-One RS (or similar).

Whatever tire works best for you. Personally I would run the widest tires I could but depending on the commute and my abilities and what I carry I might pick one with better tube availability. Me personally don't really care too much on that front as I carry tubes with me and know how to change them.

What size wheels are already on the bike you’re going to be using? Or are we trying to pick from two different bikes, based solely on the tire size?

How important is speed-v-comfort? How much of the ride is “bad” roads or unimproved surfaces? What is your riding style / position; forward/aggressive or upright / relaxed?

700x40 is going to be faster on the smooth stuff, but 650x2.0 (54mm) is a LOT of tire; it can be super-plush, but may feel slower and less responsive than the 700

700x40 quality tire.
None of the described surfaces seem like an extremely wide tire is needed.

In the 90's and even early 2000s 1.95" was the standard for MTB tires. I think 40mm should be more than enough for your commute

Yes

I'm glad to see the responses. I have my own bias but was curious to know what other people think. I'm not ready to write a review of the two bikes I bought recently but I did buy a Raleigh Knox with 27.5x55mm tires and Linus Rover with 27.5x44mm tires. (That's about 2.16" and 1.73".) By the way, they're both nice bikes but the Raleigh has a more aggressive position while the Linus has a more laid-back position. I found the 55mm tires wonderful at absorbing the shocks of running over train tracks and even hitting street curbs directly and rolling over them and rolling off them without flinching. Although that came at the expense of road feel. I thought the 44mm tires were almost at the other end of the spectrum although still absorbed a lot of road vibrations which made it way more pleasant doing groceries (compared to 31mm tires at 55 PSI). Since Trek thought 2 inches was the best compromise between speed and comfort for the Dual Sport Gen 5, I'm inclined to think they're correct (that's 51mm).

One unexpected advantage of the 650b wheels though was being able to put my foot on the ground more easily. One area I bike to has so many stops to me this is really a very pleasant advantage. Anyway, I did see a Youtube video of Cyclingabout where during one trip he had to turn back when rolling in mud and snow with his 700x38mm tires. I thought this was a bit tragic and thought I'd prefer having larger tires in case I had any extreme circumstances.

I'm not decided if I want to learn how to build frames. But one thing I have to consider is the issue of bottom bracket height. I mean once you go to 40mm on 700c, your pedals are going to be high enough that you can't put your feet on the ground as easily. So I think 45mm or 1.75" is where I think I'd go with 650b.

a 2.0 tire is a lot of rubber to push on a commute.

Seat tube angle also has a lot to do with whether or not you'll comfortably put one or both feet on the ground while in the saddle. However on those bikes they don't show the geometry spec's. So I don't know if they are even that slack compared to seat tube angles on other bikes.

There are a lot more variables to making it though those kinds of conditions than just tire width. With some types of mud, a bigger tire can be a worse option.

If comfort over bumps and cracks is your primary concern, go for a larger volume tire. Understand that there are always compromises with tire choice. What is good for one condition will be a hinderance for another.

For general commuting, I'd choose something a little smaller, like 700cX35. The tires mentioned, I'd choose for rougher use.

OP is conflating wheel size with the ability to put their feet on the ground without dismounting the saddle. Some people require that they stay in contact with the saddle for the entire ride.

Stack, reach and ST angle have nothing to do with it.

I was passed once by a fat bike while riding a bike with Tiagra hubs and 28mm Vittoria Randonneur tires. Besides, I feel like I can get plenty of speed with the Raleigh Knox with 55mm tires. Anyway, I usually ride pretty slow to save my energy for my workouts.

EDIT: Another reason why large tires can be fast is because I won't brake for large cracks on the road etc. I found on one dirt road with 1 inch rocks I would slow to a crawl with 31mm tires at 55 PSI. With 55mm tires, they actually absorb the rocks on that road.

That is how I ride, But I do it for trails .
Seat dropped and feet on the ground
It's not a proper riding position, I like dirt trails.

https://cimg7.ibsrv.net/gimg/bikefor...f5e8168bf4.jpg
This is NOT a good set up for commuting.

Your trails must be all paved and smooth, because skinny slick tires and low spoke count wheels is a terrible set up for off-road trail riding

All hard pack and clay. Fast and smooth. Miles of them
Tires are 32s, wheels are great. Just keep them in line when you leave the ground.
https://cimg9.ibsrv.net/gimg/bikefor...7bc046abcc.jpg
https://cimg3.ibsrv.net/gimg/bikefor...97f5f675eb.jpg

https://www.alltrails.com/trail/us/c...sand-oaks-park

I don't ride the asphalt

I might be imagining it but I swear bigger wheels roll faster.

My wife and I doing a smooth dirt road downhill, neither of us pedaling, I'm way faster than her on 29 vs 26 tires is the most obvious example.

I'd do whatever I could to preserve wheel diameter.

I rode the White Rim trail in Moab on 700x38, the tires were fine but I should have used lower gearing. I think you can survive your commute on 40's.

do you weigh more than your wife ?

is her riding position more upright ?

https://cimg5.ibsrv.net/gimg/bikefor...c0b3ab499.jpeg

https://cimg6.ibsrv.net/gimg/bikefor...5b2636d4f.jpeg

agree ... 40mm is a great versatile size ... + or - 2 ... 38-42 mm ...

in addition to 700c bikes with 32, 35, 40mm tires - I often ride two bikes with 26” wheels (1.75 and 2.15) and a 650b bike ...

I’ve ridden the same 26” bike with 1.5, 1.75 and 2.15 size tires ... 1.5 can be a tad small for some mixed / compromised surfaces ... 2.15 is great - but you can feel the extra size ... the 1.75 size can be a nice compromise

top pic - 26 x 2.15
bottom pic - 26 x 1.75

I chose 650b x 47mm for my gravel bike. Probably be a similar usage to what OP is proposing

Being passed by someone on a fat bike may not have anything to do with tire size.

It seems like you have already determined what you prefer, and have your reasons why.

I did want to make the point I can get plenty of speed with the Raleigh Knox with 55mm tires.

In any case, I did want to see other people's opinions. I can see now why so many manufacturers are stubborn about making skinny tire hybrids. I even saw Louis Garneau bikes convert their M1 hybrid one year to 650b then I think it was the very next year they went back to 700c. I was stupefied and wondered how that happened.

I suppose the only other factor I could wonder about is v-brakes vs disc brakes. I had a couple of experiences that showed the downside of v-brakes. One was a near accident when I didn't have enough cable tension with v-brakes. The other was when I decided I was going to prepare an old bike to sell it. When I saw the state of those v-brakes I wondered if it was worth it. But that bike was used also in the winter and the rain.

As a passing comment, one of the reasons I could consider 51mm or 2.00" tires is the overall height. I measured 700x38c tires at 70.5cm high, 44-584 at 67.8cm and 55-584 at 69.6cm. I calculated 51mm might be around 68.8cm. Seems like a reasonable height to me (short enough to put your foot on the ground, tall enough for enough speed).