Reviewed: Irwin Cycling’s medium, deep carbon clincher wheelsets
Irwin Cycling has been manufacturing wheels for a decade, first for other companies, and more recently, under its own name. With wheelsets to suit road and off-road riders, the company boasts its own testing facility that ensures the quality of its products as much as it helps ongoing product development. In this review, Australian tech editor Matt Wikstrom rides a pair of Irwin’s wheelsets featuring 38mm and 58mm carbon clincher rims.
Irwin Cycling is a modest-sized Taiwanese company with 15 full-time employees that has been working in the bicycle industry since 1996. After the first decade of operation, Irwin decided to concentrate on wheels in 2006, starting with private-label production before launching its own brand.
Irwin handles every aspect of its wheel production, which extends to weaving carbon sheets from Toray fibre for its composite rims. It’s an approach that no doubt keeps costs to a minimum, but it also serves to ensure the quality of the starting materials.
The company promotes itself on the strength of its innovation and affordability. In keeping with this thinking, Irwin doesn’t spend much money advertising its products, but is refreshingly open about its production and testing methods.
It is the latter that is perhaps the most impressive, comprising a variety of protocols for testing the strength of the rims and their resistance to braking. In the absence of similarly detailed test protocols from other brands, it is hard to judge the rigorousness of Irwin’s testing, but there’s no indication that it’s light-handed.
For example, Irwin’s continuous braking test involves loading the wheel with 80kg and applying a braking force of 6kg at a speed of 33km/h for almost six minutes. Then there is the nipple hole strength test, where a spoke is loaded with 300kg and the nipple must remain in place without damaging the rim in order for it to pass the test.
Irwin Cycling’s current road catalogue comprises low-profile (22-30mm) wheelsets with alloy rims and mid- and high-profile (38-85mm) wheelsets with carbon rims. In every instance, buyers have a choice of a traditional width or newly designed wide versions of each rim. Irwin also produces two versions of each carbon rim, one to suit tubular tyres, and another for clinchers.
For this review, I spent a few weeks riding Irwin’s latest wide profile 38mm and 58mm carbon clinchers, courtesy of one of Irwin’s Australian dealers, Autobus Cycling.
Before the ride
Every wheelset in Irwin’s catalogue is named according to a simple alphanumeric code. The prefix of the code distinguishes between alloy (IA) and carbon (IC) rims; (W) is added if the rims have the new wide profile. The suffix refers to the height of the rim and distinguishes between clincher (C), tubular (T) and/or disc (D) versions of the rim. Accordingly, the wide profile 38mm and 58mm carbon clinchers reviewed here are referred to as ICW-38C and ICW-58C, respectively.
As mentioned above, Irwin designs, manufactures and tests all of its carbon rims in its own facility in Taiwan. The new wide rim profile, which measures 26mm at the brake track with a ~19mm bed, contrasts with their traditional design that measures 21mm at the brake track with a ~15mm bed.
The wide rim profile utilises a bull-nose design compared to a sharper V-shape for the traditional width. Irwin has not performed any wind-tunnel testing with their new profile yet and do not make any specific claims about the aerodynamic performance of the 38mm and 58mm rims. The company’s first priority was to gain UCI certification, but now that the process is complete, there are plans to do some wind-tunnel testing in the near future.
Also taking precedence over aerodynamics is the braking performance of the rims. Irwin goes to the trouble of adding ceramic fibres to the brake track, and according to the company, this strategy keeps braking temperatures under 130°C to avoid excess thermal expansion, de-lamination (>130°C), tube failure (170°C), and glass transition (180°C).
Like many other carbon rim manufacturers, Irwin has developed its own brake pad compound to suit its rims, and insists that the pads always be used with the carbon wheelsets as a further precaution against overheating.
Irwin takes extra care with the bead hooks of its carbon clincher rims, choosing to fashion each precisely with an elastic mould rather than resorting to post-production machining. It’s a process that ensures the integrity of the carbon fibre and does more to eliminate air pockets than a traditional metal mould, resulting in a denser section that is better able to resist high tyre pressures as well as the heat of rim braking.
All of Irwin’s road wheelsets are built with the company’s road hubs, Sapim CX-Ray spokes and external brass nipples. The ICW-38C and ICW-58C wheelsets utilise 20 radial spokes for the front wheel and 24 spokes (laced two-cross) for the rear.
Irwin road hub gallery
The hubs feature hollow alloy axles and cartridge bearings (two for the front, four the rear) with ceramic bearings. The end-caps thread onto the axles but there is no pre-load adjustment for the bearings. Standard hub flanges mean standard j-bend spokes, a small blessing when a broken spoke needs to be replaced at short notice.
The freehub has 60 ratchets and six pawls; furthermore, each pawl offers three contact points for what must be considered an excess of redundancy for the mechanism. Regardless, the large number of ratchets gives the rider a low angle of engagement (6°) and promises a very healthy buzz when freewheeling.
I’ve already mentioned some of Irwin’s safety tests, but it’s worth revisiting a few of the details. In addition to testing the resistance of the rim to continuous braking and the strength of the nipple holes, Irwin tests the braking distance (in wet and dry conditions) of its carbon rims and carries out fatigue testing of the entire wheel. While controlled testing may not replicate real-world conditions, Irwin’s testing suggests their wheels are built to withstand a variety of insults.
The ICW-38C and ICW-58C wheelsets weighed in at 1,588g (front, 680g; rear, 908g) and 1,773g (front, 771g; rear, 1,002g), respectively (with rim tape sans skewers), a respectable effort when compared to carbon clinchers from other brands. Pricing is competitive too, since Australian buyers can expect to pay AU$2,295 for either wheelset.
Irwin’s list of international distributors is modest and some markets have yet to attract an agent, most notably, North America. However, U.S. shoppers can look to a local brand that sells Irwin’s wheelsets under its own name as part of an earlier private-label arrangement.
Each ICW-38C and ICW-58C wheelset is supplied with rim tape, a pair of skewers, two pairs of brake pads and the choice of an 11-speed Shimano/SRAM or Campagnolo freehub body. There is also a choice of bright or stealth decals for the rims.
After the ride
For this review, I fitted both wheelsets with Continental’s 23mm GP4000s tyres and inflated them to 80psi. The effect of the wide rims was immediately evident, allowing the tyres to expand to over 25mm to essentially match the width of the rims.
I’ve written about my enthusiasm for wide rims on previous occasions and I’ve arrived at a point where I wouldn’t ride anything else. There is a spectrum of wide rims on the market though, ranging 21-26mm at the brake track with rim beds 17-21mm. It is the latter that is key for comfort and grip, where wider is better.
Irwin’s carbon clinchers tend towards the wider end of the spectrum, giving them the edge over some other brands. There’s no need to run wider tyres when using these wheels: a 23mm tyre effectively becomes 25mm, while wider tyres may actually expand too much to fit a road frameset and/or rim callipers.
For the uninitiated, the extra tyre width doesn’t slow the wheels down, so there is no downside. As such, Irwin’s wheels were immediately smooth, comfortable, and sure-footed.
Both wheelsets proved to be stiff and responsive. I couldn’t identify any obvious flex or brake rub under load, and overall, the wheels added a race feel to the bike, but was more obvious for the 58s.
The freehub was loud for the 38mm wheelset, and louder still for the 58mm wheels. I’ve never been bothered by the sound of a freehub before, but towards the end of my long rides on the 58s, I was avoiding freewheeling so as to save my ears from the angry noise.
Side-by-side, the two wheelsets performed exactly as expected. The 58s were a little harder to get going than the 38s, and while it was never difficult to make a climb with the 58s, I always noticed the difference when switching back to the 38s because the bike gained some extra agility.
Likewise, there were no surprises when riding in the wind. The 58s required a constant effort to keep the bike in check; by contrast, the 38s were carefree and I was able to take my hands off the bars at any time.
What the 58s could offer was extra speed. It was just a matter of getting the bike moving in the first place, but once I was travelling over 35km/hr, the 58s always made it a little easier to keep the bike going at those speeds. Whether this was a matter of aerodynamics or the extra mass of the taller rims, I can’t say, but the 38s couldn’t provide the same kind of speed.
Mixing the 38mm front wheel with a 58mm rear wheel offered a good combination of all traits, but I had trouble with the aesthetics of mismatched rim sizes. Regardless, the wind stopped troubling me, which is perhaps the strongest argument for using a front wheel with a lower-profile rim.
During the review period, I was able to compare Irwin’s wheels with a couple of offerings from other brands. When pitted against a lightweight bespoke wheelset featuring Extralite hubs, the 38s performed well despite an extra ~300g. Likewise, the 58s were a good match for Zipp’s Firecrest 404 clinchers in terms of weight, ride characteristics, and overall performance.
Braking performance was as good (or bad) as can be expected for a carbon rim. In the dry, braking was satisfactory, just lacking the immediacy offered by an alloy rim. In the wet, more time was required to slow the bike down. I did notice some mild pulsing in the rims, wet or dry, which is to be expected for any brake track that hasn’t had any post-production machining.
Finally, a note on Irwin’s skewers: where some companies opt for lighter designs with an external cam, Irwin provides a heavier design with an internal cam that is much easier to use due to a generous lever and light closing action.
Final thoughts and summary
Irwin’s 38mm and 58mm carbon clinchers are sound products that are priced to tempt performance-oriented riders, with a few features to distinguish them from their competition. The generous width is a strong selling point, as is the choice of different rim profiles and the extra care that has been devoted to the brake track and bead hooks.
I like the company’s transparency and their readiness to share details on their production and testing procedures. Of course, neither is enough to ensure the quality or performance of their wheelsets, but brands with much bigger reputations manage to charge more while revealing less about their products.
There’s no evidence of cutting-edge aerodynamics in Irwin’s wheels, which is perhaps the strongest argument for a carbon wheelset. Missing too, is a certain race-winning reputation and brand recognition. It is the latter that is perhaps most important in terms of inspiring the confidence of a buyer.
All things considered, the pros and cons appear to cancel each out, so buyers are free to let the overall appeal of the brand and the wheels (and maybe the noise of the freehub) decide the matter for them.