I've been enjoying the benefits of tubeless tyres on my mountain bikes for years and was keen to see how the technology transferred to the road. With the IRC Formula RBCC Tubeless tyres I was certainly getting to test it at the highest level. In many ways these are the best road tyres I have ever ridden, with outstanding grip in dry and wet conditions.
My plan had been to ask road.cc for some tubeless tyres and hope they sent me a nice tubeless wheelset to test at the same time. They didn't, dang it, so it was off to the workshop to bodge a 'ghetto' tubeless conversion on my regular Shimano RS80s.
After three days of experimenting with various combinations of tape I finally got them to stay inflated. To save you time, the winning configuration was three layers of electrical insulation tape, ensuring at least one layer got right up under the rim hooks on each side to create a tight seal. (Note that the first thing IRC tells you in the instructions is to use only tubeless-ready rims so following my advice will, more than likely, invalidate your warranty.)
Fitting and inflation were otherwise straightforward, and once the sealant was in and distributed around the inside of the tyre, all was secure and airtight. On the first test run I pumped them up to 110psi, anxious to avoid the tyre rolling off the rim in the middle of the first sharp bend, but nothing untoward happened and I gradually began running them at lower pressures, curious to know whether not having to worry about pinch flats would result in a comfort premium.
Surprisingly, I found the answer was 'no'. At 90psi (IRC's minimum recommended pressure) the tyres felt unpleasantly lifeless and, rather than eliminating road vibration they seemed to accentuate it. It was a sensation I can't explain – my only guess is that the thick casing is less compliant than in a standard road tyre and this becomes more obvious as you make greater demands on the casing's flexibility. Whatever the reason, the feeling went away when I increased the pressure to 100psi, where these tyres really zing.
This is also my first experience of a 25mm tyre over a 23mm. The round-profile tyres sit pleasantly plumply on the rim; and measured with the callipers across their widest point came up at 25.5mm. The large-volume casing certainly holds a lot of air, which is very noticeable in the ride quality. I thought for a while the council had been round fixing the roads, but that was just a dream.
The other great quality in these tyres is the grip. I took them to northwest Scotland for a few days' testing on the steepest, twistiest, wettest, gravelliest, farm-manuriest roads I could find and, honestly, it was all I could do to get them to step out of line. Only when I deliberately braked late and hard into a sharp left-hander at the bottom of a steep hill did I finally coax the back tyre into some sort of skid, and even then it was more of a correction of direction than any cause for alarm. It feels like your brakes have had an overhaul. Most impressive.
Grip can often be at the cost of something else, most typically lifespan or increased drag. With a few hundred miles on the tyres they still look like new and over the longer term we shall see how they fare. So far there's no sign of cuts or abrasions on the casing, and not a sniff of a puncture.
Regarding drag, I saw no evidence in my Strava stats of a sudden dip in my average speed. I kept notching up the PBs (mostly on the downhills – I don't get many on climbs since I turned 50!) and the smooth ride certainly makes it feel as though you are going quickly and is a great fatigue reliever.
IRC says the grip is thanks to a ceramic compound derived from rice husks, which create microscopic ball-like particles with spreading tentacles that stick to the road. This is then combined with a harder centre-line to the casing which keeps the tyre moving quickly on straight lines. Whatever the science, the results are excellent, and if you are thinking of going down the tubeless route I can recommend these as all-weather tyres par excellence.
Grippy, high-quality tyres with the advantages of tubeless, though you may find they run best at higher pressures
road.cc test report
Make and model: IRC Formula RBCC Tubeless tyres
Size tested: 700 x 25
Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
IRC rate these as all-condition race tyres.
The RBCC tyre uses ceramic compounds devised from rice, mixed with the rubber, to create a tyre that IRC claims has enhanced grip even in wet conditions.
IRC has lots to say on tubeless tyre technology. The advantages are:
Low rolling resistance
Reduced natural leakage
Tell us some more about the technical aspects of the product?
The RBCC rubber compound was developed by IRC.
Rice Bran Ceramic is derived from rice. Rice bran (or the outer husk of an individual rice grain) is ground to a fine powder, mixed with a thermosetting resin, and super-heated. When cooled, the block is pulverized to create millions of porous, ball-shaped structures with semi-rigid fingers extending in all directions. These Rice Bran Ceramic "balls" are then kneaded with the rubber and molded into tires. The spikes which extend from the RBC reach out and grab the uneven road surface for increased traction while the pores will wick water from the road surface to create a larger tire-to-road contact patch.
The Formula PRO TUBELESS RBCC shoulders are layered with RBCC compound for high grip performance and the center tread is composed of hard compound which strikes a balance between wear-resistance, grip and rolling resistance.
NR-TEX(NATURAL RUBBER) INNER AIR SEAL SYSTEM
To bring the advantages of a latex tube to a tubeless tire, IRC developed a new high-elasticity tire liner based on natural rubber which offers lower energy loss, reinforced with silica. Despite being slightly poorer at retaining air than the butyl rubber used for typical liners, air retention is sufficient, especially for tubeless construction.
These look quality from the packet: no surfeit of flash from the moulds, the bead tidy and the moulding true.
The combination of high volume comfort and high grip makes for a happy riding experience. I didn't get the hoped-for improvement in comfort at lower pressures, though.
Great so far, no punctures or signs of tread damage; only 500km covered at the time of writing though, and we shall see how they look after 3000!
As a tyre this is quite heavy, but once the lack of inner tube and inclusion of sealant are taken into account, they are pretty competitive.
A definite boost in comfort, though not due to running at low pressures. I found these rode best at 100psi.
Haven't tyres got expensive? You do save the price of two inner tubes, mind.
Tell us how the product performed overall when used for its designed purpose
These tyres impressed in their road-holding, puncture resistance and comfort.
Tell us what you particularly liked about the product
Fantastic grip, well made, big air volume, stay securely seated, puncture resistance...
Tell us what you particularly disliked about the product
I found the ride quality at lower pressures disagreeable.
Rather noisy at cruising speed and above
Did you enjoy using the product? Yes
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
Use this box to explain your score
These are incredibly grippy tyres that you would trust with your life on the worst road conditions. Wet or dry, stopping distance was better than anything I've ridden before. The wide, high-volume casing makes for a comfortable ride and the build quality is excellent. They are quite noisy, though.
About the tester
I usually ride: Cannondale CAAD10 My best bike is:
I've been riding for: Over 20 years I ride: A few times a week I would class myself as: Experienced
I regularly do the following types of riding: touring, sportives, general fitness riding, mountain biking