How many of us ever really stop to think about those two rubber hoops that are the interface between our bikes and the road surface? I know that I don’t, apart from checking pressures regularly and moaning about “bloody expensive for two bits of rubber” every time I have to change them. The style of vintage motorcycle tires is essential to the look of a vintage motorcycle, but it’s worth thinking about the advantages of modern technology. With that in mind, let’s dig into the history of vintage motorcycle tires.
Motorcycle Tire Performance
Motorcycle tires are so much more than just “two bits of rubber”, and of course a lot of design and development work is carried out by clever chaps in lab coats to make them do a variety of tasks without which riding a motorbike would be much less pleasant and safe – in fact it would probably be downright impossible. A tire’s main role is to provide grip, which is important enough for a car, but even more so on a bike, particularly when you’re cranking it right over in the twisty bits.
A tire also has to provide a certain level of feedback, enough feedback to travel up the suspension to your hands and backside (front and rear tire respectively), giving you an idea of how well they’re gripping, and of exactly when they’re going to let go: there’s nothing I hate more than a tire that lets go without a mild bit of slide beforehand, as if to say “watch it, son, don’t overdo it now”. They also have to last as long as possible whilst offering as much grip as possible in all kinds of road, traffic and weather conditions.
Early Vintage Motorcycle Tires
Of course, like most of the elements that make up a modern motorcycle, tires weren’t always such feats of technology. Until John Boyd Dunlop came along, vintage motorcycle tires were simply thick, solid rubber strips that were nailed to wooden wheel rims. Although early pneumatic tires really were a massive step forwards with regards to comfort, they were very prone to puncturing and didn’t offer much grip on wet road surfaces. For several years motorcycle racers routinely had a couple of spare inner tubes and seeing a racer stopped by the roadside (racing circuits didn’t exist back then) tending to a puncture was a common sight.
Tire Tread Technology
As motorcycles became heavier, more powerful and faster, tire technology had to keep up as best it could. Tire structures began to get tougher, the rubber on the tread became thicker, and tread patterns themselves became more effective and even started to be designed to accommodate various road surfaces. This is why off-road tires tend to have big, chunky tread blocks and road tires have more or less pronounced groove patterns: the former are designed to dig into loose surfaces and provide traction, whereas road and sports tires are designed to give maximum grip as well as traction on smooth tarmac – the grooves are there simply to evacuate water in wet conditions. The grippiest tires are racing slicks, although they have to be operating at very specific temperatures to offer those phenomenal amounts of grip, hence the tire-warmers you see at races, and that no self-respecting track-day diva would be without.
Tubeless Tires Return
Until the mid-Seventies, most tires used inner tubes, although from the latter part of the decade onwards, tubeless tires began to appear, primarily as a result of the appearance of cast alloy wheels. As for their structures, motorcycle tires were all cross-ply until the mid-Eighties, when major tire manufacturers, such as Pirelli and Michelin, began making radial tires that were better suited to bikes that were becoming more and more powerful, needing wider, stiffer tires as a result. Different rubber compounds, an aspect that until then had been reserved for racing motorcycles, began to appear on road bike tires, with sports machines using very soft compounds similar to those on racing tires.
Modern Tires for Vintage Motorcycles
Manufacturers still make vintage motorcycle tires for classic motorcycles, of course, albeit with the benefit of modern tire technology and manufacturing processes. In fact, over the past few years the demand for these tires has expanded from the core of classic and vintage motorcycle restorers to the street-tracker/bobber/café-racer market. Nowadays at bike shows and custom meets, it’s commonplace – not to say somewhat anachronistic –to see Firestone Champion Deluxe, Coker or Avon Safety Mileage tires, amongst other retro options, fitted to machinery as diverse as old-school Frisco-style choppers, BMW 9Ts and Triumph’s latest version of the Thruxton.
Here at Black Douglas, we mainly fit the Sterling with Avon’s classically styled Speedmaster MkII vintage motorcycle tires. These tires, despite closely resembling the tires that were common on bikes for many decades, and having a very skinny appearance – only 76 mm wide – make the most of modern tire technology to offer surprisingly high levels of grip, feedback and longevity. Indeed, on the Milan to Bristol run that the company organised earlier this year, they behaved faultlessly, even taking a torrential downpour on French country roads in their stride. And not a single bike suffered a puncture on the entire trip.
So next time you’re out on your bike, spare a thought for your tires – they really are your machine’s unsung heroes.
Marc Michon for The Black Douglas Motorcycle Co.