Project Phil Part 5: Tyres

Off-road tyres
One of the main reasons I chose the Croix de Fer frame as well as all the other component selections, was to be able to run larger tyres, particularly larger off-road tyres.  I ordered some the Schwalbe Smart Sam 35c tyres as they were quite cheap and had gotten good reviews.  Oddly they are marked as both 700c x 35c and 622-37 which is contradictory.  They measure close at 34.7mm at 65psi at the widest point.  Sadly they won't fit under the SKS Chromoplastic P45 mudguards that I have, however without the mudguards the clearances on the frame were reasonable, I reckon you could probably go up to 37mm wide tyres; this is consistent with what Genesis states.

I took the bike on it's first ride (which I'll write about in the next post) with these tyres on a muddy towpath and dirt trail.  The trail mostly consisted of mud, hardpack, some gravel and lots of dead leaves which hid a lot of rocks and branches underneath.  I also have ridden these tyres on pavement around London.  Firstly, for a cheapish tyre they are actually quite supple; I inflated the front/rear to 60psi/70psi and they absorb a lot of the road bumps, they feel like the just glide over most pavement bumps.

In the mud, they give quite good grip and tend to shed it reasonably quickly, the knobs transition smoothly from the centre to the side which gives a smooth lean-in.  The semi-continuous tread down the middle of the tyre gives low rolling resistance for a knobbly, there is still a very slight buzz on smooth surfaces.  On hardpack and gravel they give good grip, braking is good and you had to really brake hard to break the front wheel from the ground.

The carcass itself is quite thin, which probably gives it its supple feel.  However I'm guessing they aren't the best commuting tyres, although on road the knobs lift the base of the tyre off the pavement so it probably avoids most hazards on the street like glass.  The grip on pavement is decent, although not as good as a slick because of the decreased contact area, overall a good cheap tyre for off-rad jaunts.

Update 20th December
I managed to get the Schwalbe Smart Sams to fit underneath the guards, normally the front mudguard of the SKS P45 Chromoplastics has two indents either side to fit between the forks, the standard Croix de Fer forks are a lot wider so these aren't really necessary.  They are the narrowest part of the mudguards so cutting them off gives you a lot more clearance.

There is about a 5mm gap around most of the tyre and mudguard at the tightest points, you probably wouldn't want to go any tighter than that.  This amount of clearance isn't ideal although I guess if you want maximum mud clearance you probably wouldn't be running full length mudguards.

The rear mudguard has a bit more space, although it's a little tighter around the brake bridge.

On-road tyres
I had to get these Strada Bianca tyres on back order for about a month, I'd read about them for a bit and despite my bad experience previously with Challenge tyres I thought I'd give them another chance.  These are different from the Elites in that they have a double anti-puncture layer which you can see above in red, it's a kevlar liner which is glued to the inside of the carcass.

The reason I chose these tyres was that there is a dearth of high-end wider slicks, once you get above 28mm wide there are mostly only touring oriented tyres.  The Panaracer Paselas I had on Mr Ramen were great, however I couldn't find them in the folding version in all black.  Also the Strada Biancas are a very high 260tpi which is unrivalled for a tyre this wide, in theory this should give it a very supple ride.

The tyres are a bit odd to mount, they are billed by Challenge as open tubulars and it shows; out of the packet they come in a belt-like shape which is completely flat, this is really apparent when you mount one bead like in the picture above.  It takes a bit of stretching to get the tube in and then the other bead on, but there is a bit of give in the kevlar bead and it's not too hard, if a little bit different to a normal tyre.   Once both beads are on, it looks a lot like a deflated tubular with a completely flat tread.

  The reccomended pressure is 55-115psi (4bar to 8bar) although I only inflated it to 75/90psi (5/6bar) initially.  The width measures at 31.2mm and there is plenty of clearance around the forks and chainstays.  The SKS P45 Chromoplastic mudguards fit quite easily which is good, I intend to have these tyres on for most of the time and put on the knobblies on occasion.  The tread itself is a traditional file pattern which is not dissimilar to the Challenge Elite tyres, except a lot wider.

  The first impression riding it down the street was that they felt quite fast, almost as fast as an average 23 or 25mm tyre.  However they felt quite supple but still a bit hard over the bumps.  They feel very grippy and the large round profile encourages cornering.   I later deflated them to 60/75psi (4/5bar) and this changed the feel of them immensely, the tyres are super supple and just float over bumps.  They feel super grippy and ride quite quickly even at a slightly lower pressure.   I'm yet to do a longer ride on these and will have to write a more detailed review.

   Ok, not a good sign but I punctured on the first time I rode it to work.  A large shard of glass cut right into the back tyre and made a pinhole in the tube.   This was after 15km, as well after riding them for another 40km or so there were 3 more cuts on the tyres but thankfully no punctures.  Judging by the stickyness of the rubber and my experience with the Challenge Elites, I'll take a guess that these tyres will cut up quite easily over time.  I went in knowing this, but from this brief experience these tyres are more meant for country roads rather than glass strewn London streets.   That's what I have Schwalbe Marathons on Charles for, this bike is for the weekend.

Project Phil Part 6: First ride continues here...