Choosing bikes - 700c x 44mm or 650b x 47/48?

After a lot of thinking and internet research and talking with my cycling friends, I've come down to choosing between the Trek 920 and the Kona Sutra.

I live in central Maine.  90% of my biking is day rides that are between 30 and 40 miles.  By mid summer I'll probably be taking a ride once a week in the 55 to 65 mile range if I follow my cycling patterns from previous years.  I ride a mix of horrible pavement, gravel roads and rail trails.  Single trail and very rough jeep/logging trails are not part of the choosing criteria. 

I ride a Surly Disc Trucker right now with 38mm tires.  After riding for the past month, I am absolutely sure that I want to move up to a wider tire.  The last ride I took (40 miles) had long stretches of very rough, broken, frost heaved asphalt that really took a lot of enjoyment out of the ride and left me feeling more worn out than I think I should have been.

So that brings us to the two bikes in question.  These bikes are not the best for just eveyday riding, but I also want to be able to pack them up a bit for some touring and bike packing.  Since I've been riding the Surly for the past five years, I'm used to the stable ride at the expense of agility.  I'm OK with that.  Same with the weight.  However, I do not want to get any more sluggish than the Surly is with 38mm tires.

Even if there were bikes available now, there would be no Sutras or 920s in stock within any reasonable driving distance for me.  I was able to try out my friends Kona Sutra in the Boston area a couple of months ago.  It was a 54 and I take a 56 with Kona bikes, but it was OK to ride on for an afternoon.  We rode around Salem.  I was surprised that it seemed more nimble and fun than my Surly trucker.  The front end is very similar regarding HT angle and trail.  Maybe it was the shorter chainstay, maybe it was just having lots of fun with a friend.  It was only one afternoon and I did not get to A&B it with my Surly which was back home in Maine.  The bike was riding the stock Mondial 40mm tires.  I liked it.

My intent would be to use Rene Herse 700c x 44mm (Snoqualmie Pass) tires on the Trek 920 and 650b x 48mm (Switchback Hill) on the Kona Sutra.  The Trek has a BB drop of 85mm, so any 650b/27.5 wheel is out of the question, IMO.  The Kona has a BB drop of 72mm.  I will be using 170mm crank arms.  I am 6' tall with a 34" inseam, if that matters.  Either bike can use fatter tires with more tread for the rough stuff if called for, but I'm concentrating on the bulk of my riding time to make my choice.

I have no experience riding a 700 x 44mm tire.  I tried a 42mm tire on my Surly once, but it was really cheap, massively heavy (over 900g IIRC) with lots of heavy tread.  I got one mile down the road and turned right around, went back home and changed it back to the Panaracer Pasela 38mm.  I'm pretty sure the Rene Herse 44mm tire would not feel like that.  I have no experience at all with any 650b/27.5 wheel equipped bike.

So that's pretty much it.  I've picked the two bikes I can afford that suit my purposes best as far as I can determine.  They both have differing pros and cons, but the biggest factor for me to make my choice is to choose between a 700x44 or 650bx47/48.  I'm not sure how to do that at this point.  I'm hoping someone has some experience with these tire and wheel sizes and can give me their thoughts and opinions.

Side note:  Kona is totally out of Sutras until autumn and reportedly no framesets until spring 2021.  Trek has framesets now but no complete bikes.  Either way, it's OK with me.  I can wait if I decide the Sutra is the better choice.  If I went with the 920, I would definitely build up a frameset.

Thanks for any thoughts, opinions, advice, etc.

Running a 44mm will help with compliance a bit, but this is also weighing up an alu frame&fork 920 ride feel against steel. May find alu too harsh. 

I would lean toward having a bike with a lower bb drop, if using a 700x44. This will offset the tyre height. 

Have used SBH 48mm extralight black for a year or so. It is a nice riding tyre, though it does roll slower than a 700c. I kind of think at your height you'd prefer the 700x44. 

Tried the same in a 700x35mm on my 70mm bbdrop frame but didn't like the ride height. That's just me though. 33mm max feels right. Would love to try the 44mm on a frame which keeps same height, along with front end feel/trail? similar. 

Note the 920 has a 5mm longer chainstay than your bike. 

Feel if you could find a bike/frame with around an approx 80mm bbdrop and a shorter-end chainstay, with the right front end 44mm feel, that would be the way to go. 

Have read an earlier run of the 700x44 extralight were around 340gm.

Using 99spokes you can compare your bike and these side-by-side for geometry, across sizes.

A lightweight wheel set is going to help offset the negative effects of the larger tire size. I’ve been riding 700x45 Ramblers on my bike on a carbon Wheel set that weighs 1450g. Pretty wonderful setup with that air volume to smooth things out at low pressures. Look at tire weight too, some large differences there as well.

Hard to go wrong with the Ramblers. I’m 240 lbs and they have held up very well, roll great on pavement and dirt, surprisingly good traction in mud and sand.

Personally, I’d be fine with an alloy bike and this wheel/tire setup. The larger diameter, big, soft tire are real bump-crushers. 

shiggy wrote:

 IME those two RH tire/diameters will have a similar handling feel.
the 650B wheels will retain their agility more if/when you go to a heavier or more treaded tire than the 700C.

get the frame That appeals to you more

I'm not seeing this.  A 700x44 is significantly bigger in circumference than a 650bx47.

I agree that if I need to go fatter for rougher stuff, I would be better off with the 27.5 format.  That's making me lean toward the Sutra.  Then again, there's a guy on bikepacking.com that put big, fat 27.5 tires on his 920.  I can't remember the exact size, but they were pushing 3".

JWK1 wrote:

I'm not seeing this.  A 700x44 is significantly bigger in circumference than a 650bx47.

I agree that if I need to go fatter for rougher stuff, I would be better off with the 27.5 format.  That's making me lean toward the Sutra.  Then again, there's a guy on bikepacking.com that put big, fat 27.5 tires on his 920.  I can't remember the exact size, but they were pushing 3".

what don’t you see? The 650Bx 47 is heavier and wider (closer to 50mm than 47). This affects the handling, slowing it. 

I think the point when comparing 700x44 with 650x47, is that they (for all practical purposes) have the same width, but the rolling diameter is very different (and for that matter the tires I've looked at, the 650b is a little lighter for tire and wheel in that size.  The tire alone is about 50g lighter. 

Because of the diameter difference, the 700c is going to have better roll over characteristics (shallower impact angle), and hold speed better.  There is a reason why mountain bikes have settled on 29" tires.  They are faster in rough conditions.

Ultimately it may come down to how low you want to sit in the bike - which is going to depend on BB height & axle height as you have noted.  Personally, I like to be able to accelerate out of a corner without pedal strike, but many would rather glide through a corner with low center of gravity.  Personal preference...

I had a similar dilemma and couple years ago and went with 650b and 47mm tires. I have no regrets. It's a dedicated gravel rig and the wider tires make for a plusher ride and better control. And I'm still pretty damn quick too. When I wear out my MTB Byways I'll probably go even bigger and get Donnelly X'PLOR MSO's in 650Bx50. 

I propose to consider Giant Toughroad SLR GX frame for your application. Very stable, massive tire clearance. I actually use 700x45 Panaracer Fire Cross on mine and I still have room to spare.

Choosing a bike with more clearance opens up the possibility of using fast rolling mtb tires as well, which frankly, are as fast as most gravel tires.  I don't like the size/maneuverability of a 700x50-60 so I tried an odd thing and went 700 rear/650b front.  Now all my bikes are set up that way.  If you want a fast rolling tire that won't cost as much as the Rene Herse, try the Schwalbe G-One Speed.  Mine at 48mm on a 23 id rim has been a great all 'round tire.  It suffers a bit in sandy/rocky terrain but then makes up for it on smooth dirt and pavement.  It has held up to my pseudo mtb rides and mounts and seals without a fuss.  They make a 650b/27.5x2.0 version that would be a good rear tire.  The front tire is a little harder to match.  The Speed on the front does not have enough grip for cornering and I crashed once when it could not climb out of a rut.  The G-One allround is not a bad tire but is definitely slower.  I use a Byway in 650x47 and it has been durable but it is not any faster than a quickly rolling mtb tire so I'm switching soon to my Schwalbe Thunder Burt which tested just as fast but has more float/traction. 
My favorite rear tires is a Conti Raceking 2.2 with the center blocks worn down.  It rolls as fast as the G-One Speed but has more float and side traction.  Now you are talking about 57mm of clearance which is why all my 'gravel' bikes are really converted mtbs.  Without the big tires I would be forced to hike-a-bike in sand all the time.  When I tested my mtb tires against my gravel tires and found no speed disadvantage, I pretty much gave up on 38-45mm tires.   

My Gravel King SK 650Bx48 on a 23mm rim ended up at 52mm wide after a year. The new one is still 50mm. Sandy and rocky? No problem, front or rear.

But JWK1 is talking about slicks.

shiggy wrote:

 

No, they are not the same width. And JWK1 is specifically talking about the Rene Herse tires.
From the RH site (which match my own experience with their tires) the 700x44 measures 43mm on a 23mm rim, the 650Bx47 is 50mm on a 23mm rim.
Weight: 700x44, 378g (standard casing), 329g (extralight)
650Bx47, 441g (standard), 413g (extralight)
The 650B is 7mm wider, 63-84g heavier (for the same casing).
Yes, the 700C is larger diameter. 

The width and weight difference basically offsets the diameter difference as far as handling IME. There is a minor change in the rollover feel as the higher volume of the 650B allows lower pressure and literally smooths the bumps.

I have both the 700 x 44 Snoqualmie Pass, and the 650b x 48 Switchback Hills, both in Extralite versions. The larger diameter of the 700x44 increases the trail geometry of my bike, and slows the steering down. It is not noticeable on dirt, but it is on roads. 

On tarmac, the 650b x 48 tyre takes more steering input but the bike steers faster. 

As I now have the fat 650b wheels for rougher routes, I am now trying the Barlow Pass on the 700C wheels for routes with smoother gravel and/or more tarmac. I prefer the faster steering response of the 38's than the 44's, and expect I'll not go back to 700 x 44's for this bike.

This might be late getting to the party, but I had a Trek 920.  It's a very comfy bike.  Almost too comfy.  From my roadie background, I didn't like it's long chainstays and bouncy fork (even though it was made of aluminum).  Plus, the tires it comes with stock are 700x50C or 2.0" 29er tires.  This added to the suppleness, but added weight and made it feel sluggish in my roadie frame of mind.  

Main thing to think about with your idea of the 920 with 44C tires:  It's designed with 2.0"/50C tires in mind, so that BB drop would get a little too low with tires much smaller than that.  But I never tried that, so I don't have first hand experience.  It may be just fine.  Just thought I'd share so you don't run into possible pedal strike issues.  I took off the stock 2.0 29er MTB tires and put on some Schwalbe Marathon Supreme 50C tires for comfort and flat protection.  They were kinda supple, but just too beefy to be considered anywhere close to nimble.

I ultimately sold my 920 and went with a bike with comfy 40C tires on it - a Cannondale Topstone (aluminum).  It feels close to a road bike to me, but has cushion from Soma Supple Vitesse 40C tires.  The 920 was great for moseying along and bikepacking, but I like a little more pep in my bikes.