The Review | Six months on IBIS 741 Carbon Rims
We first received some of the first Ibis 741 rims back in June and were blown away by the physical size of the rim, boasting a potentially game changing 35 mm internal width. After six months and 1000 km of hard riding and racing, (including the Finale Ligure EWS) it is time to find out how they performed. Are Ibis onto something, or is 35 mm a step too far?
So why run a 35 mm internal rim? Well, Ibis claim that a wider rim delivers more strength and stiffness, and the resulting improved side wall support allows you to run lower pressures in your rubber, increasing traction, reducing rolling resistance and increasing braking control. With the mass release of the new ‘plus’ size wheels and wider hub standards on the near horizon, we are about to experience a flurry of new ‘wide is best’ products hitting the market. The Ibis 741 rim is already here and offers increased traction and tyre stability, while still being able to use conventional tyres.
The set we tested came mounted on some nicely engineered Ibis hubs (for $1450 Ibis will offer the wheelset with an upgraded DT Swiss 350 rear hub) which proved reliable through the testing phase. Spinning on Enduro® bearings we had no issues with reliability; and the freehub uses substantial pawls. We approve of the standard J spokes which are easy to replace should one break, and we found that the strong rims required no attention or re-truing throughout the test. The weight of the 41mm rims is also very impressive, with each rim weighing in at just 475g and only 1650g for the complete wheels, acceleration was swift and lively.
We were left in no doubt as to the torsional stiffness of the massive rims, no matter how hard we drove them into corners there was not a hint of flex or bending, just brutal solidness and a lazer sharp steering response. We tried these wheels on a number of bikes and the feeling was always impressive, but be warned, they do increase the volume of your tyres so you need to check you have enough clearance in your frame.
However, there are many really strong carbon wheels on the market, and we were interested to test their low pressure performance. The increased width of the Ibis 741 wheelset dramatically increases the tyres contact patch and allows you to run 4-6 Psi less pressure, while still maintaining side wall support and avoiding burping. We were extremely impressed with the stability of the tyre on the hook-less rim. When running 18-24 Psi the stability of the tyre was excellent, offering very high levels of traction and performance, without any hint of tyre instability.
Even at pressures as low as 18 Psi, you can hammer the tyre into the turns without any hint of pressure loss. At these lower pressures, the level of grip on offer is ridiculously good, the tyre wraps around every tiny trail feature; grinding up any climb and holding any flat turn. When pushing aggressively through bermed corners we found that with pressures under 22 Psi we could still detect roll in thinner side walled tyres, but was improved greatly with ‘enduro’ casings such as the Schwalbe Supergravity. Our 75 kg tester found the sweet spot for most tyres to be between 22-24 Psi, offering hugely improved traction and massive stability when railing berms.
However, we did experience some issues when it came to tyre choice. The tyres that perform best with these rims are those with rounded profiles, Maxxis Minions DHF, Schwalbe Hans Dampfs, and Maxxis Shorty’s all performed very well. However tyres with defined shoulder knobs or very square edges performed less so, with the breakaway point being moved to a shallower angle of lean and a resultant highly unpredictable handling. With the new ‘plus’ sizes about to drop, many tyre manufacturers are now working on wider tread patterns so maybe later in the year there will be more tyre choice. Riding in Scotland we could not find any mud tyres that suited the wheels, most common spikes have a narrow tread profile and look like a Mohawk on the burly Ibis rims. If you live somewhere where a Minions or Hans Dampf works year round you will love these rims; but the dramatic influence these rims have on the tyre make options limited.
The rims also feature a ‘hookless bead technology’, with a thick rectangular side wall where the conventional inverted J hook is normally found. This has allowed Ibis to add a lot more material to the side wall of the rim, creating a stronger interface that is more resistant to damage. Ibis claim that this is 50-300% stronger than other leading carbon rims on the market when it comes to impact tests. However, during testing we did crack a side-wall on the early pre-production model when the tyre deformed (22 psi) and the rim caught a rock at high speed. The damage occurred in a rough rock garden while racing the Enduro World Series in Finale Ligure, and when racing things do break. Ibis ensures us that the production models use an improved carbon layup and we have had no problems with the new replacement.
When it comes to mounting tubeless tyres, the hookless technology works great, tyres pop on with a track pump, first time, every time. The hookless side wall holds the tyre admirably and we have experienced no issues with burping or pressure loss, even when riding aggressively with pressures as low as 18 psi.
We love the look of the rims, the workmanship and high level of finish scream quality, and they certainly stand out when fitted. We did find that with the wider profile rim, there is less tyre side wall overhanging and thus protecting the rims surface, so if you ride a lot in rocky terrain and like to thread through tight gaps, the rims do suffer more than most from glancing blows, and it was not long before our pair showed plenty of battle scars.
There is a lot to like about the new Ibis 741 rims, if you choose to run slightly lower pressures in your tyres you will be rewarded with impressive traction with no observable loss in rolling speed or stability. The 741 is certainly one of the most confidence inspiring wheels through challenging terrain and the steering accuracy is ridiculously sharp. We like the sensible price ($1299) and the lightweight construction. However, we found that the 35 mm internal width presents unpredictable results with some tread patterns. Ibis have certainly shown us the future, but if you live somewhere requiring specific types of rubber, you may need to wait for tyre design to catch up.
For more information about the ‘New Wide’ Ibis 741 rims, check out the Ibis website.
Words and photos: Trev Worsey