The most important thing on your bike – these interface with the road and are vital to staying upright. Now, Good-Bikers tells the story of bike-riding rubber.
Hoops, rubber, tyres (or tires!). Call 'em what you will, they're one of the most important parts of your bike. And they can completely transform it – from a gripless, wobbly piece of old nonsense, to a sharp-steering, super-stable, streetseeking weapon.
Now, if we were talking about a brand-new 2015 bike, straight from the fancy-pants showroom, this would be a pretty short feature. Tyre sizes for most road bikes nowadays have become standardised around a few fitments, and within those sizes, you can select from a high-mileage commuting tyre, through a sticky sport-touring hoop, right up to a near-slick trackday tread, which would let you lap within ten per cent of a proper racing tyre (if you had the minerals of course...)
So new bike riders – they've got it properly easy, but what about us guys : the folk on the older, cooler, more fun metal? Well, we still get good options – but we need to work a bit harder, is all. Put a bit of effort in, and you can find excellent, modern rubber for almost all sizes, even the proper weird ones. Here's our route to rubber happiness...
Motorcycle Tyre History
Let’s start by looking back. We’re sold on bikes from the 1960s to the end of the 20th century. So what’s been happening in the last 40-or more years to those black, round things we call tyres ?
1960s
These were utilitarian times, with utilitarian machinery: everything used inner tubes of course – bike wheels were (almost exclusively) wire-spoked, with no way to make an airtight seal in the rim. The tyre construction was simple too: no such thing as ‘low-profile’ tyres, so there were only two numbers: the width in inches, and the diameter of the wheel, in inches.
So a BSA Gold Star had a 3.00 19 front and a 3.50 19 rear: three inch wide front tyre, and three and a half inch wide rear, both on 19 inch diameter spoked wheels. The profile was unspecified, so was, notionally, 100 per cent.
The one good thing about this generic nature of sizes is that there are still plenty of tyres made in these sizes today: especially the classic tyre designs from Dunlop, Avon and Metzeler. Dunlop’s TT100 was the first tyre to lap the Isle of Man Mountain course at 100mph, and is still made today...
1970s
In this decade Japan emerged as the major player in motorcycling bringing an amazing array of machines to the common man. At first, tyres largely stuck to the old sizes, meaning pretty narrow, tall carcasses, on 18 and 19 inch rims. But as frames got stiffer, power outputs increased, and things like disc brakes and monoshock rears appeared, the rubber had to adapt.
The easiest change was obviously to increase the width of the rear, giving a larger contact patch, and hence more grip. Wider designs didn’t work so well with highprofiles though – they get too heavy, and the tall sidewalls flex too much, generating excessive heat. So in the mid 1970s, firms like Metzeler began producing /80 and /90 section designs, which allowed wider rubber, with lower sidewalls, giving a more stable, lighter tyre.
The 1970s also saw the adoption of cast aluminium wheels, which let firms use tubeless tyre designs. Special sealing beads on the rims, together with an airtight inner liner on the tyre meant the inner tube could be dumped, saving weight, improving reliability and enhancing performance all round. In racing, Michelin moved towards dumping tread patterns altogether, building semi-slick, and slick tyres for GP racing in 1977.
1980s
We might have had ZX-Spectrums, CD-players and electric hair crimpers. But the world of bike tyre technology was still feeling its way. We’d moved over to metric tyre widths at least, so the 3.00 and 4.25s were making way for 100- and 120-section tyres. No-one had any idea how big to make the wheels though. Japanese engineers veered from 19-inch fronts to 16-inch rears, then swapped to 16 inch fronts, with seemingly no rhyme or reason.
Kawasaki’s early air-cooled GPz range used skinny-to-modern-eyes 18-inch rims, with 100 or 110-width fronts, and 120-130 section rears. Then the water-cooled GPZs arrived, using 16 inch fronts and 18 inch rears, getting slightly wider. There was still some distinction in smaller models – something like Suzuki’s RG250 actually had the same width tyres front and rear – a 100/90 16 front and 100/80 18 out back.
But towards the end of the decade, a consensus was beginning to form, with Honda’s CBR600F sporting 17 inch rims front and rear, albeit in skinny 110/80 and 130/80 sections. The 17 inch wheel made a decent compromise in terms of steering, tyre profile shape, tyre wear, and wheel mass, and it’s the size that most road and road-race bikes have settled on since.
1990s
Now, we were starting to get somewhere. The production-based 750cc superbike class was white-hot in terms of development, and the tyre sizes were starting to pan out. Honda’s RC30 (from 1988) was using a 18 inch back rim, but Kawasaki’s ZXR750 came out in 1991 with a 180/55 17 rear, and a 120/70 17 front.
As a result, you can still shoe your ZXR with all manner of 2015-spec hot-poop hoops, while the RC30 is stuck with ancient sport-touring rubber, when you can find it. Widths at the rear went up quite quickly, from 160 to 170 then 180. The 190 section rear first appeared quite early on in the decade, on Ducati’s 916 in 1994, but it took another couple of years before it was widely adopted, on Suzuki’s 1996 GSX-R750 SRAD, Kawasaki’s ZX-6R and ZX-7R. The 200-section rear just missed the 1990s, first seen on the 2000-model Kawasaki ZX-12R...
Modern Days
Modern rubber technology (albeit in old sizes) can transform your bike. It stands to reason, it’s the unstoppable march of technology, so the tyre you buy from a dealer in 2015 is very different from one you’d have bought in 1975. The materials used in the nylon plies of the carcass, and the chemical compounds used in the rubber will be from the same sources as those used for modern tyres. Indeed, there are still new tyres coming out to suit older bikes – like Metzeler’s Sportec Klassik, launched this year. Metzeler’s Jim Worland told us :
"The tyres we produce for older machines use the most recent technology. For instance this year, we have launched the Sportec Klassik: a cross-ply tyre that used the latest carcass materials, profiles and compounds. We looked at radial development but found the crossply Metzeler Belt System was the best technical solution. We have incorporated compound and profile technology from our multi-award winning Sportec M7 RR Supersport tyre to give bikes of the 70s, 80,s and 90s the best possible tyre performance."
But enough from the PR man, what about the riders? We asked two of the alltime greats in bike racing, Niall Mackenzie and Ron Haslam how they thought tyres had come on since the 1970s and 80s. Niall Mackenzie began his race career on Yamaha RD350s in the early 1980s, then rode 500cc two-stroke GP bikes and became a triple BSB champ on fourstrokes. He’s ridden road bikes as well from the 1970s on. He says:
" The road tyres of the 1980s weren’t the best, and there was a huge void between road and race tyres whereas now there’s not; they’re so close. What you can do lap times-wise on a stock bike on road tyres now is incredible, but back then there was no chance."
Ron Haslam is a genuine legend. He made his GP debut in 1977, and he’s competed in virtually every field since, from the TT to 500cc GP, and everything in between. He says:
"The road tyres you get now really are the equivalent of what I used to race on. For example, at Donington Park, on a production Fireblade, I’m lapping faster than I did when racing on a 500GP bike, and yet I’m on road tyres! I would say it’s in the 1990s definitely that the race tyres would be equivalent to today’s road tyres. And I think you can get road tyres now that are actually ahead of what we used to have back then."
Tyre Milestone Timeline: What Happened When ?
1969: Dunlop tyres lapped the Isle of Man TT course at over 100mph for the first time, so were henceforth renamed the ‘TT100’, and became probably the first "performance upgrade" tyre.
1974: Metzeler built the first low-profile tyres in /80 and /90 sections.
1977: Michelin developed semi-slick and slick racing tyres for Grands Prix racing, helping Barry Sheene (Suzuki) to win that year’s 500cc world title.
1983: Metzeler launched its MBS – Metzeler Belt System, using a Kevlar belt around the outside of a crossply carcass
1983: Pirelli developed the first radial tyre – the MP7, used in very limited numbers on the European version of the super-exotic Honda VF1000R
1984: Michelin began using radial tyres in 500GP racing
1987: Michelin launched its A59/M59 radial tyres
1987: Metzeler releases the ‘Comp K’range, using silica for better wet grip.
1992: Pirelli and Metzeler develop a 0° steel belt for rear tyres
1992: Michelin adds silica to its wet race tyres, massively
1994: Michelin begins using dual-compound tread on its race tyres, allowing softer shoulders for better edge grip and harder centre for better mileage.
1997: 0° steel belt for front tyres (both Pirelli and Metzeler)
Sidewall Tyre Decoder : What Means What ?
The numbers on the side of a tyre can seem intimidating at first, but they are pretty simple in all honesty... Just see the figure below (click to enlarge)
