High performance racing bicycle technology and technique
Cyclocross - IRC Serac CX Mud Tubeless Tyre
Friday, March 23rd, 2018


IRC Serac CX Mud Tubeless Tyre


Paul Horta-Hopkins


A review of the IRC Serac CX Tubeless Mud Tyre.


The IRC Serac CX Mud tyres are one of three in IRC’s ‘cross range. The others are the Serac CX and the Serac CX Sand. The last two come in tubeless, tubeless X-Guard and a standard tubed version. The Mud is only available as tubeless only. Although there’s nothing to stop you running a tube in a tubeless tyre.


The IRC Serac CX MUD

The IRC Serac CX MUD


IRC technical specifications for the Serac CX MUD are as follows; stated size is 700x32c, so UCI legal. Inflation guide is 45-75psi, which is 3-5 bar, but who runs them that high? Weight on the box is 380g, mine came in at 386g which is not super light, but no porker either.


According to IRC, the Serac CX MUD is designed for muddy/rainy conditions. Unfortunately I only got to try them out in two muddy races during the test period; blame global warming! IRC adopted the original Serac CX tread pattern with modifications to improve performance in the slop.


The tread is directional for front and rear wheels, so pay attention when fitting. Alternating big/small ‘L’ shaped blocks run down the centre tread. These have 12mm of clear rubber between them, to help clear any sticky mud. The shoulders have two large blocks, with smaller blocks repeating down the sides. The smaller blocks line up with the small ‘L’s in the centre.


To prevent air escaping through the casing, a layer of butyl is applied to the inside of the tyre. This also adds an extra layer of protection from cuts. As an added bonus the butyl layer can be patched with a glue patch, handy for repairing cuts. IRC call this Internal Air Seal. You can also get the Serac CX MUD in an X-Guard version. This 40x40tpi cross mesh belt, gives a claimed 40% improved resistance to side cuts. Handy on rocky courses.


The inner is covered in a butyl layer, for extra protection, better air seal and can be repaired with a patch

The inner is covered in a butyl layer, for extra protection, better air seal and can be repaired with a patch


I set the Serac CX MUD up on two sets of wheels. The first was a pair of Pro-Lite Bortola A21W wheels. The second wheel-set was an older set of Ambrosio hubs and Mavic’s new Open Pro UST rims. Fitting to the Bortolas was simple and I achieved a good seal straight away. The Mavics however were a whole different story!


After swearing and snapping a cheap tyre lever, it was off to the LBS to get some Pedro’s tyre levers. After much huffing and puffing, I finally heaved them on. However what I didn’t realise is that in all that struggle I’d damaged the rim tape. Cue much pumping, followed by steady deflating until I realised what was happening. Two layers of tape finally sorted the problem, but this particular combo was not one I would want to be wrestling out in the wilds! Mind you the Seracs weren’t the only ones to struggle to fit on those Mavics. I had similar problems with Schwalbe and Clement tyres.


Anyway once the tyres were on how did they perform? First test was round the local rec; giving the dog walkers something to moan about! I have a little circuit that is all grass, but with a natural tree based slalom course. I ran the tyres at around 27psi, according to my pump and I weigh in at 65kg, to give you an idea. In damp autumn conditions, greasy, but not sloppy, the Serac CX MUD gripped well. Tight corners around and over tree roots weren’t a problem, with no unexpected slips. Onto the figure-of-eight around the goal posts and again the Seracs held on well. Here I try to get as tight and fast as my skills allow, to force a slide or slip, but they held on.


Weighing in at 386 grams

Weighing in at 386 grams


So riding around the park was fine, let’s try a little race action. Taking them onto the Happy Valley round of the London X League and riding round the practice lap was fine. The surface was short grass and there was little mud. A twisty downhill section through the woods posed no problem. Everything was looking fine, until some of the youth riders decided to add their own touch to the track.


Dumping bottles of water at the bottom of a short uphill corner, created a greasy skid pan. What had been a slightly muddy slope was now proving a challenge, with many riders opting to run up. The Serac’s tread was unfortunately just a little too small to really grab the loose surface. While they were fine making the turn, I couldn’t make the climb; possibly rider’s fault as much as the tyre?


Away from racing and time for some gravel riding around Sussex. Here the Serac CX Mud proved an excellent off-road tyre. Although a tad narrow for ultimate gravel cruising, they were fast over the close-cropped grass on the Downs. I was running them around 35-40psi and this gave enough cushioning, without too many rim strikes. On road they are a little noisy and while not as fast as say a Schwalbe G-One, they didn’t feel totally out of place.


IRC, made in Japan

IRC, made in Japan


After putting the Serac CX MUD tyres through some Sussex chalk and flint they have stood up well. Flint strewn gullies will catch out any tyre that is less than bomb-proof and IRC’s sidewall protection seems to work. However if you do experience a cut, the butyl inners will allow you to repair the damage.


So to wrap up, for me the Serac CX MUD tyres were more of a high grip, general purpose tyre. Good for leaving on your wheels until the mud gets really slippy and deep, then they begin to struggle. They will cope better than most general purpose tyres and shed the mud well, but you need to make the most of that practise lap.




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