584×47 mm — my beautiful but failed experiment

A couple of weeks ago I had the idea to buy a second wheel set for Battle Cat, my gravel bike, to expand the where I can ride it. The plan was to keep the 700c wheel set I’ve been riding for the past two years for longer gravel rides or for road riding (using road tyres, obviously). I would then buy a 650b/27.5” wheel set and a pair of wider tyres with more bite to venture into more gnarly terrain.

I inquired with the frame manufacturer what tyre width would be safe to use in the frame and set out to find a good, used wheel set from DT Swiss because I’ve had nothing but great experiences with these so far. After being told that 1.9“ or 4.83 cm wide tyres should work and still provide enough clearance, I quickly settled on the WTB Sendero 650b × 47 mm pneus.

The result was this sexy setup:

My gravel bike Battle Cat with 650b wheels and WTB Sendero tyres

The wheel set I found was an older pair DT Swiss M1700 MTB wheels with a decent internal rim width and the Ratchet Free Hub System. There was a bit of a setback when I found out that the last person to service the hind wheel didn’t just fail to remove a massive radial run-out, they also centred the rim over the hub body and not over the axle, resulting in a rim that was too far on the left. After getting this fixed for a good amount of money, putting the tyres on tubeless and the wheels into the frame, I saw that it was a tight fit but doable with no tyre rub on the frame or fork.

Well, that changed after the first 15 km of singletrack riding on Saturday. I pushed the tyres the way you would and to my great dismay, they expanded/deformed in a way that caused tyre rub on the left chain stay twice in one revolution on a perfectly true back wheel.

What I’m left with is the choice to either sell the wheel set and tyres again or to find slightly smaller but equally gnarly tyres for the wheels. The problem here, of course, is that smaller tyres also mean an even smaller wheel diameter and a further lowering of the bottom bracket, something that already took getting used to going from 700×40c to 584×47c on the Litespeed T5 Gravel frame I’m riding.

There’s one silver lining to all of this, albeit a fact that left me with a very substantial urge to slam my head into my desk repeatedly because I could’ve saved myself the trouble of buying another wheel set:
I started checking out which 700×40c rubber is available that would give me better grip on wet forest floor than the Donnelly X’Plor MSO I love so much. I found a number of options, the WTB Nano 40 being the supposed best among them when set up tubeless. The only issue is that WTB recommends running these tyres on a rim with at least 20 mm internal width and my DT Swiss CR1600 Spline db wheels are 22 mm wide externally … … … or so I thought.
Turns Out ™ I had misread the specs of the wheels because the spec sheet of the bike I bought them on didn’t specify whether the 22 mm were internal or external width figures. Long story short, they have an internal width of 22 mm, meaning they are right in the goldilocks zone width not just for the WTB Nano 40 but for many other ~ 40 mm wide, supple gravel tyres.

I’m likely going to try and get my hands on the Nanos if I can find them for a decent price and maybe, just maybe I’ll get my wish of a gravel bike capable of some gnarlier paths but still fast when I need it to be.

Goodbye 650b wheels, I hardly knew ye.

Alex Hoffmann @mangochutney