IRC Formula Pro Tubeless RBCC 25 tyres – review

Japanese-made tubeless road tyres that match a high quality compound with excellent ride quality

They’ve been making bicycle tyres since the 1920s, but Japanese company IRC aren’t the first names on anyone’s lips when they’re looking for a new set of tyres. But that level of experience at making tyres for all types of bikes – and motorbikes as well – manifests itself as real quality and that’s shown in their tubeless road tyres. And specifically in the 25mm Formula Pro Tubeless tyres on test here. 

IRC have aimed their Formula Pro Tubeless RBCC 25mm tyres squarely at racing, but they’re also a balanced compound, designed to perform well in both the dry and wet. Clichéd as it may be, this kind of balance makes them a good choice for changeable British conditions as they offer enough grip that you won’t be tentative around corners even when it’s really wet.

The compound IRC have used on these tyres is called Rice Bran Ceramic Compound1, which is where the RBCC in the name comes from. It has this name because, believe it or not, Rice Bran Ceramic is derived from – wait for it – rice. Normal rice. To make the tyres, the outer husk of rice grains are ground down into a powder, mixed with a resin and super heated. After it’s cooled, it gets pulverised to make Rice Bran Ceramic ‘balls’ which are mixed with the rubber and moulded into tyres.

The reason for this is that the Rice Bran balls have millions of little tentacle-style extensions that spread out in all directions and improve the tyre’s grip. Similarly, the pores that are created using this compound help to move water from the road and create a larger contact patch.

RBCC is the compound used in the tyres, and it stands for Rice Bran Ceramic Compound, so called because IRC mix Rice Bran Ceramic balls in with the rubber before forming the tyres in order to increase grip

One of the ways in which tubular tyres have had a bad rap over the last few years is mounting. And while it’s true that some tubeless tyres can be a pain to mount, the same is true of clinchers (Challenge’s Paris-Roubaix tyres I tested earlier this year were a prime example, as they were so tight on first fitting that there was much wailing and gnashing of teeth trying to get them on). It’s also not always totally the fault of the tyre, as rims play an equally important part in the process. Quality rims will make for easier mounting, while poor quality rims can make life near impossible.

I mounted these on Bontrager’s Aelous 3 TLR wheels, and the process was heart-warmingly simple. They went on quickly and easily, and the seal was good enough that I inflated them using track pump – no air compressors necessary. In fact, if all road tubeless tyres mounted this easily, it might do something to lessen the skepticism around the genre as a whole.

While I’m on the subject of seal quality, IRC claim that these will leak air slower than the equivalent clinchers with tubes due, in part, to their ‘NR-Tex Inner Air Seal System’. This is a high-elasticity tyre liner that helps to prevent air escaping from the tyre. While IRC happily concede that it’s not as effective as a butyl tyre liner, they reckon that it’s more effective than a clincher and either latex or butyl tubes. It’s very difficult to measure, but I certainly haven’t had to pump these up any more frequently than my standard combo of Continental GP 4000 II tyres with Conti’s own butyl tubes. You certainly won’t be having to pump these up every day.

Coming in at around 300g per tyre , they’re certainly lighter than the equivalent tube/tyre combination (in the same width), but the one other factor to add in is sealant. That’s probably another 50g or so for each which means if pure weight savings are your thing, you’ll likely not save a lot – if anything – by running these. IRC do make some super-light tubeless tyres as well, though, that’ll knock around 50-60g off the weight per tyre if you’re looking for a weight-weenie special. But weight isn’t the only reason to look at road tubeless, as ride quality and rolling resistance can be very high as well.

On a set of 27mm wide Bontrager Aeolus 3 TLR rims, the tyres opened up to look more like 28mm than a standard set of 25s

Combined with the 27mm rims on the Aeolus 3s, the 25mm offered by these tyres really opened up, to the point where they look far more like 28mm tyres mounted. The result of that is a fantastic ride quality, and even on my Cipollini – which isn’t known for its comfort – the tyres made the ride noticeably more comfortable. IRC recommend that you run these between 90-115psi, but I’ve been out on them inflated to 80psi with no problems at all. As you can imagine, at 80psi they’re rather nice indeed and you could probably go ever lower if you wanted.

The final test is, of course, puncture resistance. I’ve ridden these for around three months in a variety of conditions and not had a single puncture yet. That’s impressive, and even more so considering that they don’t boast anything in the way of extra puncture protection. Of course, whether or not you puncture is often very much in the hands of the cycling Gods, but these certainly aren’t flimsy enough that you’ll be getting your hands dirty every ride. Running them with sealant adds an extra layer of protection, but having given these a thorough check over before writing, the sealant hasn’t even been called into play yet, either.


As tubeless tyres go, these are top quality. They mount easily, roll nicely, provide a comfortable base for the bike and have plenty of grip in the dry or wet. I’ve also not seen any visible signs of wear after three months’ worth of riding, which suggests they’re durable enough to make them a worthwhile investment, even though they’re far from cheap.


– Width and grip make them a comfortable and stable base for your ride
– Leak air very slowly so you won’t be re-inflating every ride
– Mount easily and seat using just a track pump


– Not cheap

1To be honest, I wish more tyre manufactures would make up inventive names for their compounds, like Continental’s superb Black Chili. Since it’s difficult to actually convey anything useful in a compound’s name, you might as well go crazy. I didn’t know what the RBCC in the title stood for until I did some research, as would anyone else who was interested in buying a set. With that in mind I’d have called this one ‘Speed Assassin’, because it just sounds good.


Newsletter Terms & Conditions

Please enter your email so we can keep you updated with news, features and the latest offers. If you are not interested you can unsubscribe at any time. We will never sell your data and you'll only get messages from us and our partners whose products and services we think you'll enjoy.

Read our full Privacy Policy as well as Terms & Conditions.