Bish Bash Bosh Part 2: Tyres

Probably one of the most important components on a bike or any road going vehicle for that matter are the tyres.  They are the sole part of the bike that interfaces with the ground and can absolutely make or break the feel of the bike.  Previously I had run 30mm wide slick Challenge Strada Biancas for road and 35mm Schwalbe Smart Sams for off-road duties which barely fit the frame.  The Strada Biancas were fantastic tyres, extremely supple and grippy however they suffered from punctures.  The Smart Sams were so-so tyres, not particularly supple and average grip.

What am I trying to achieve?

In short, better off-road capability and a smoother ride with less punctures... doesn't everyone?
I've become more interested in wider more supple tyres generally as well as off-road riding.  The market has grown significantly in this regard in the past few years since I built Phil, now there are plenty of tyres that fit the bill.

I was spoilt by the suppleness and smooth ride of the Challenge Strada Bianca but didn't want to deal with the punctures, so in my mind the solution is to go tubeless in conjunction with sealant.  All else being equal, you get a more supple ride too with tubeless.

What about 650b?

Another factor that went into my consideration was wheel size, disc brakes allow more flexibility in wheel size choice as you no longer have to worry about the brake surface of the rim matching the brake mounts on the frame.  Many disc brake bikes have the flexibility to mount 650b or 700c wheels, also the rolling diameter of a 50mm 650b tyre is about the same as a 32mm 700c tyre.  The possibilities for off-road tyres would be opened enormously with 650b as there was a huge amount of choice of MTB tyres.

I considered this for a while, the frame clearance would allow about a 2.25" x 650b MTB tyre in the front and about a 47mm wide in the rear, but in the end stuck with 700c as I wanted to be able to fit more road oriented tyres in the end.  Going with 650b meant I would only be able to fit wider tyres, narrower 650b tyres would be too small and the ride height of the bike would be lowered noticeably which could cause problems.  I figured anyway I could always get a second set of wheels in 650b purely for this purpose.


The tyres that met these criteria were numerous, I settled on having a two pairs of tyres, one for off-road and one for road.  For the off-road tyres the first ones I considered were the WTB Nano 40c's.  These were really popular with the gravel crowd and had a nice smooth micro tread that would roll fast.  I wasn't really too interested in a full on MTB tread, rather something that would be suitable for loose over hard/hardpack type conditions.  There were also the Schwalbe G-Ones, however I decided that these had too little of a tread and would be insufficient.  In the end I settled on the Maxxis Ramblers, these were extremely light for a 40mm tyre at 380g and had a supple 120tpi carcass and a not too aggressive tread.  

The Rambler

They came in at 370g which is 10g lighter than claimed!  I fitted them with tubes and inflated them to get them into the right shape ready for mounting tubeless.  I had read elsewhere that they come up a little undersized, however after inflating and leaving overnight they came up to about 41mm @ 70psi and 40mm when inflated to 30psi.  Although it's not massively wider than the 35mm Smart Sams I had before you can see the difference below.

The Bish Bash Bosh frame is meant to clear 40mm tyres and I had measured it beforehand when I was considering 650b.  Definitely the fork has plenty of clearance, you could easily go up to a 700c x 45mm tyre even.  

The seatstays had plenty of room too, however this isn't usually where the pinch point is.

This is where it is usually tight... the chainstays have to fit the crankset and the tyre side by side.  There is about 5mm clearance either side of the tyre so not much room to go larger.  I was a little disappointed by this, as I originally entertained the idea of fitting 2.0" x 650b tyres however it looks like the largest 650b tyre that would fit the chainstays would be about 47mm.   Still this is plenty of clearance for my purposes, and I'm well aware this is not a high-end frame meant for a 650b conversion.

So far so good!  In the next part I discuss the wheel components...  Thanks for reading


  1. I've been looking at this frameset for a bit and really appreciate the build options you've mentioned.

  2. Cool. Have you tried the 650x47 yet? I'm very keen to go larger than my 40's(x 700)

  3. Hey, no it doesn't fit! Largest would probably be about 650x42 I think