It’s been done to death, but I’m still undecided….. Gravel wheel size.

Here’s the deal….

GF’s gravel bike needs a new rear wheel. Current set is the cheapo hubs and rims that came with it. Chain jumped the cassette the other day and ripped into the spokes. They’re heavy wheels with very slow pick up and narrow.

My wheels are a mishmash of Mavic rear and no name up front after the Mavic hub split at the flange. Need some new rubber, but have had a few pinch flats and rim dings due to the rough tracks here in Italy.

Riding is about 50/50 road and gravel/off road. Tend not to bother riding if it’s pissing it down and it’s sloppy. Besides, we’ve got the “big” bikes for proper trails and rough stuff.

Many of the fire roads/tracks here in Italy are rough. Certainly rougher than the gravel/forest roads around Munich which is where I was when I bought the bike.

So the question is… Stick with 700c and fit the largest tyres the frame can accommodate or pick up some 650b wheels and run bigger tyres?

Thinking being that on the road with slicker 650b the experience is much the same as 700c,but don’t have to be quite so gentle off road.

Often ride loaded up on my way back from the shops (had a pinch flat on the front a could of weeks back… Combination of rough track and loaded up). Thinking 650b le reduce that chance.

Can pick up a new set of DT Swiss G 1800 for under 300€ in either flavour for the GF’s bike.

What’s the consensus?

As far as I’m aware, 650 wheels were initially used so they could fit bigger tyres into the frames at the time, as newer gravel bike have capacity to fit 45/50mm tyres (or even bigger) on a 700 rim, I don’t see the point of using 650 wheels now unless you’re riding still on an older frame with limited tyre clearance or ride an extra small bike.

If you can get a 45-50mm tyre in with 700c go with that. Tyre choice is wider. Also, keeping all bike the same means it’s easier to swap things around should you need to.

What clearance are you dealing with, and what frame size/overlap does it have at the moment if any?

I’ve gone with 27.5 x 2.25 in mine (Brother Cycles Mehteh) rather than 700×50 as I’m on a small frame and the overlap was too great on wider/taller 700C’s. If it wasn’t for that limitation I’d probably have gone for 700C’s as I find the larger diameter and rollover angle etc. of the bigger wheels does a lot of the work that a higher volume tyre does in terms of comfort and hitting roots/rocks etc.

Personally I’ve found that if you can run at least a 700×45 with no issue in terms of clearance to fork/frame/toes then going any wider than that on 27.5 instead doesn’t give you as big an advantage. If the choice was <40mm 700C tyres or a decent size 27.5 then I’d pick the smaller wheel.

What clearance are you dealing with, and what frame size/overlap does it have at the moment if any?

Just checked both online and with vernier calipers.

GF’s bike says 40mm, but calipers say there’s 57mm. No toe overlap.

My bike (Ribble CGR) says 45mm, calipers again say 57mm. Bit of overlap, but new shoes and I could move the cleats forward a little.

Guessing 50mm shouldn’t be a problem with the right rims.

Both manufacturers say 47mm with 650b.

The max tyre clearance on my frame is 700x40mm so when it’s time to change wheels I’ll most likely go 650b to fit some 45-50mm tyres as I do like to run lower pressures on rough surfaces. However, if my frame had clearance for bigger tyres then I’d probably stick with 700c.

40mm tyres are fine off road IME, even on rough stuff.
My 50mm are luxurious all things relative.

IMO, go for a 700c (better rolling etc) and as fat a tyre with a supple carcass as you can.

I’m running 700x50c and it’s great, I see no reason to try 650b if you can get a large volume 700c tyre to fit

As far as I’m aware, 650 wheels were initially used so they could fit bigger tyres into the frames at the time, as newer gravel bike have capacity to fit 45/50mm tyres (or even bigger) on a 700 rim, I don’t see the point of using 650 wheels now unless you’re riding still on an older frame with limited tyre clearance or ride an extra small bike.

this

and as fat a tyre with a supple carcass as you can.

and this. Ideally tubeless – makes a huge difference IMO.

When I had a 650b gravel bike, decent tyres were a pain the hoop to find in stock or at the very least seemed pretty pricey compared to the relative ease of finding 700c ones.

With hindsight it made me wish i’d gone with 700c, quite often.

didnthurtFull Member
As far as I’m aware, 650 wheels were initially used so they could fit bigger tyres into the frames at the time, as newer gravel bike have capacity to fit 45/50mm tyres (or even bigger) on a 700 rim, I don’t see the point of using 650 wheels now unless you’re riding still on an older frame with limited tyre clearance or ride an extra small bike.

I’ve probably posted this near word-for-word myself in the past, but there are a lot of bikes out there nowadays with clearance for an entirely different class of 650 tyre… if the choice is 650×47 versus 700×42, I’s tick with 700. But 650×2.2 is an entirely different story on rough terrain compared to 700×45 – obviously you give up some speed on tarmac, but…..

Riding is about 50/50 road and gravel/off road.

Personally speaking, I’d base the decision around how much of the non-road 50% is ‘off road’ compared to rough road.

If a reasonable chunk is mountain bike territory then 650b would be a stronger option than if the vast majority of the surface is just a bit rough with very occasional ‘MTB’ trails.

For the use / bike you describe OP, ime the 650s is comfier and better all-round. The volume counts for a lot off-road and on-road they can feel good too as long as you’re not after a typical road-race bike feel.

I rode my VN Amazon for many years with either 700×40 or 650×47 wheels and tyres on. When it came to buying my Topstone last year, I could have gone with either nad opted for the 650×47. Of course, there are times where I with I’d gone the other way, but overall, I think it was the right choice. FWIW I still have the Amazon and both wheel sets for it. That’s now for winter/touring duties and is currently set up with the 650×47 too.

Yo….

I’m not a roadie despite now owning a pair of bib shorts.

Have found I quite enjoy the climbs in a sadomastic type II fun kind of way, but certainly get a kick out of caning it down asphalt at 80kmh and getting the braking/apex just right (other than that last time I overcooked it and slid across the tarmac…. still suffering the consequences of that one).

But my main kick is just getting out and pedalling.

The volume counts for a lot off-road and on-road they can feel good too as long as you’re not after a typical road-race bike feel.

That was my thinking….

From all of the above, I think that it’s fair to say that neither is wrong and only you know what surfaces you will be riding on. One day 650b will be better, the next it’ll be 700… I have stuck to 650×47 on my Ragley Trig fun gravel bike but also have a Croix de Fer that can fit 700×40; in that format, it has been over the Corrieyairick. It’s a more sedate bike, the Trig is for bopping about in the woods…

Not that any of this makes my decision any easier.

It’s not like I’m swapping tyres every few weeks or months.

Tyre is very likely to be something pretty slick and ridden till the threads are exposed (like the current G-Ones) or I trash it.

Hmmm

My only drop bar gravel bike is a Pinnacle Arkose X from years back. It came with very cheap 700c wheels and 40 Nano’s. It felt incredibly lively and much better than I expected on road BUT I bought it for more offroad than on so I switched the wheels for much more expensive 3T 650b and put 47s on it.

I gained a bit of ‘float’ on rougher stuff but the on road performance dropped off a cliff despite the new wheels being lighter and betterer……it just feels dead on the road.

Now I have a trek procalibre short travel 29er. With some modifications I think that now covers the ‘hard core gravel market’ and so I reckon the best gravel bikes now will be nearer to a road bike so my next one will be a 700c and more agressive stance. This is not to criticise the Arkose, it was of its time but now I’d only consider a 700c with clearance for 50mm.

700c for me simply for the ease and range of replacement tyres and tubes

I’d def go with 700c if you can fit 45-50mm in there, and only have an extra 5mm or so of clearance for 650b

Tyre is very likely to be something pretty slick and ridden till the threads are exposed (like the current G-Ones) or I trash it.

My gravel/fat tyre road bike takes 700 or 650, been on WTB Byways or 50mm G-One Speeds for years. Haven’t ridden a 700 gravel bike in ages basically because 650 works so well for me there – and I have a 32mm tyred audax bike or 2.3″ rigid alt bar 29er either side of it. Loved my gen 3 Arkose for a light gravel all-rounder though, if my 2 drop bar bikes had to become one it’d be something like that.

Cheers folks…..

You’ve pretty much convinced me to stick with 700c wheels.

Got Mavic Allroad rims, but I’m not a fan. Think they’re 22mm internal and the rear has a big old dent.

Rambling….

Question is, what tyres would you recommend for 80/20 road/gravel in 45-50mm width…..?

Pathfinders seem to very popular, I had the slicks in 42mm and found they cut up on dry gravel. Didn’t last long. Loads of others people I know have had much more longevity than I did.

My partner runs G One Bite on hers gravel bike, she also only rides in the dry…as in not raining, but she does ride winter days when it’s not raining….so still wet. Grip appears ok, but that’s pretty much hardpack gravel, green lanes and roads.

I use G One Ultra Bite, slow on road, but I like the fact that the grip is decent through forests all year round. 700×45 for me. I put up with the slightly slower on road to be able to go exploring in all conditions.

@alpin, I wasn’t entirely sure if you said what max tire size was with each wheel size?

In general, for the use case you describe, bigger tire is better. So, if the 650b gets you that, easy choice. On my Warbird I could run 50/ 53 mm front and rear in 650b, and 45/48mm in 700c. That was a noticeable upgrade when it was big rocks or deep sand.

However, many  (recent) bikes, don’t list better clearance, so then it’s a bit trickier:

650b gets you lower BB and stand over, both good.

700c gets you way, way more tire choices, especially in the newer, fast rolling tires. I can’t remember any of the high scoring new tires coming out recently that had 650b. Most existing 650b tires max out at 47mm.
If you have clearance for 27.5 x 2.2, then you have options again.

Oops, missed @alpins last comment.

ok. 700c it is. Which tire? just have a look at bicyclerolling resistance.com.

In their screen you  can filter for anything like puncture protection, wet grip, weight etc. And of course, most importantly, rolling resistance, and select only the sizes you want.

Question is, what tyres would you recommend for 80/20 road/gravel in 45-50mm width…..?

I really like my Continental Terra Hardpack. They are basically a semi slick centre with a few knobbly bits on the edges. For 50/50 road and off road on tracks etc and avoiding schlop as you said you do, they are great. They are noticeably supple in use.

https://www.bikeradar.com/reviews/components/tyres/gravel-bike-tyres/continental-terra-hardpack-tyre-review

There’s also these Terra Trails a slight step up in knobbles. Same carcass etc. Uber cheap.

Continental Terra Trail Performance TR Folding Gravel Tyre – 700×45

Mrs_oab has Schwalbe G-One All-round. They roll well, but I have to say she’s had two punctures in a year, compared to none on my Continental’s, and she’s only 8st and a smooth rider…

Same as Matt’s missus for me but 40mm. I wouldn’t go wider for 80% road. Still ride anything round here off-road, not rocky but can be chunky flint. I have had to stick the odd worm into them, but they haven’t destroyed themselves, just gradually worn out. Very limited grip in anything muddy though, as you’d expect.

GF’s bike says 40mm, but calipers say there’s 57mm. No toe overlap.

My bike (Ribble CGR) says 45mm, calipers again say 57mm.

Have you checked width and height at both brake bridge, bottom bracket and fork crown?

Bit of overlap, but new shoes and I could move the cleats forward a little.

Don’t overthink it, a bit of toe overlap, in 99.99% of cases you’ll never ever notice.

My Camino came with Goodyear Connectors, which I think are in a 45 width.

They seem pretty reliable on & off-road and have tightly packed knobs around the centreline which I think helps to keep it rolling OK on the road.
I haven’t tried any other gravel tyres though, so can’t really comment on how they compare.