The Current Fracas Around Hookless Rims

Generally I like to keep up to date with advances in cycling technology. This includes increasing gear numbers, adoption of disc brakes, carbon fibre frames and parts, electronic gears and the like. I like to think I hold views on bike tech that have an appropriate balance between reality and fantasy.

For example, disc brakes seem to me to be welcome because they offer superior braking in some conditions, such as heavy rain. Given that braking efficiency on a bike is mostly down to friction between the tyres and the substrate (in my case tarmac), I've never found disc brakes to have braking performance superior to rim brakes. And I would not like to be on a cycle tour and have problems with a hydraulic brake system.

Similarly, I've not found electronic gear shifting to work better than cable actualted gear shifting - the advantages to me are the absence of gear cables to thread through the bike frame, and the ability to have more than one pair of shifters (particularly in the case of a time trial bike).

I tried tubeless tyres on my commuting bike (since retiring, it's now a winter bike). Theoretically, this should have been an obvious case for tubeless tyres as it has pretty wide rimes and tyres akin to a gravel bike. But fairly soon after adopting the tubeless setup, I suffered a puncture that wouldn't seal. At the end of the day, I don't really get many punctures (touch wood), and keeping a fleet of bikes with tubeless tyres topped up with sealant just seems like a lot of faff - and when the inevitable unsealable puncture occurs, it's a real mess business to fix, probably involving an inner tube.

In the last week or so, the online cycling news sites have had stories about professionals suffering tyres blowing of hookless rims. Hookless rims seem to offer an advantage to the manufacturers as they are cheaper to produce (aka increased profits). Unfortunately the absence of hooks means that the specifications of rim and tyre need to be carefully observed, and tolerances are pretty specific. Tyre pressures also have to be kept quite low.

This report at road.cc describes two such incidents occurring about a week apart. We're treated to the spectacle of a bike with an unseated tyre, splattered with sealant and with a broken foam insert tangled in the frame. Here's a video showing it happen.

There's a load of comment with the UCI expressing concern, the Professional Cyclists Association saying they want them banned, and the tyre and rim manufacturer saying there is nothing unsafe if the correct tyre is fitted - and fitted correctly. A commonly suggested explanation is that the rider must have hit a stone or a pothole which transiently increased tyre pressure above safe limits. Or that the tyre fitted was too narrow for the rim.

But here's the thing. Professional cyclists are supported by highly experienced mechanics who know how to do stuff. If hookless rim/tyre combinations are really that sensitive to tyre choice or road surface or an exact tyre pressure, they really can't be that safe. And in the hands of home mechanics, what issues might we see?

The adoption of some of these technologies seem to be driven my manufacturers confecting reasons for their adoption, backed up by apparently gullible media claiming them to be a great advance. It seems that some high profile major wheel manufacturers have moved their product lines entirely over to hookless rims - would the UCI really ban them? Could they? 

Newer technologies seem to push cyclists away from maintaining their own bikes to having them serviced or repaired in a bike shop, which I think is a shame as it undermines an understanding of how bikes work. For my part I got to grips with electronic shifting, with tubless tyres, with hydraulic braking systems and I can repair and maintain all these things. I think all this will come to bear on the hookless rim situation if they lead (even indirectly) to an uptick in cycling accidents.