The terms Cross-Ply and Radial signify two different ways you can produce a tyre.
Cross-Ply tyres are also known as Bias-Ply and they’re not just used in the world of motorcycles and scooters, they’re also used in cars, for trucks, tractors and other transport.
Cross-Ply tyre history
The Cross-Ply method of tyre construction has been around longer than Radial tyres. Cross-Ply tyres were invented by Dunlop in 1888 and first used on a bicycle, coupled with inner tubes to hold the air pressure. They quickly took over from other efforts at providing improved comfort and traction. It’s no surprise that people wanted to ride on a cushion of air on cobbled streets and broken roads, rather than a solid rubber tyre! For decades there was no other alternative, but Cross-Ply was – and still is – an excellent design.
Radial tyre history
Then in 1948 Michelin invented the Radial tyre, which developed the Cross-Ply design with a different method of construction that allowed you to run a pneumatic tyre without requiring an innertube. These new radial tyres also allowed Michelin to produce tyres with different properties to Cross-Ply and as cars and bikes became faster and roads of better quality the demand for radials increased.
The Citroen 2CV was the first production car to come with radial tyres, in 1948 but it took until the mid 1960s for them to become a common standard fitment in the car world. Biking, as ever, was a step or two behind and the first motorcycle with radial tyres was the Honda VF1000R, in 1983.
The tyre above is a clear demonstration of the wires used in a radial tyre’s carcass.
Cross-Ply vs Radial motorcycle tyres
The main difference in terms of the tyre’s construction is the way the carcass is made. The vast majority of motorcycles produced in the last 20 years will come with radial tyres fitted but some modern bikes still come with cross-ply tyres, as cross-plys give a more comfortable ride, which suits some bikes, like Harley-Davidsons for example.
The main difference is that a radial tyre has a central belt from which the rest of the tyre is built on. This belt gives the tyre less flex and more stability, which helps the tyre retain its profile, even at high speed or under heavy cornering forces, which is what helps a radial tyre give a bike precise handling. You’ll be able to tell a radial tyre as it’ll have the letter ‘R’ in its name, i.e. ZR17 or HR17, etc.
A cross-ply tyre is constructed using a network of interlocking cords, weaved together. A cross-ply tyre has a much thicker and stronger sidewall, as this helps the inner tube support the bike’s weight. Cross-ply tyres are still popular in the off-road world as they are lighter than radials, can be run at lower pressures without the sidewall deforming and they resist impacts better than a radial tyre too.
Cross-ply tyres can’t be used at speeds of over 150mph and even at high speeds under that, the tyre will change shape far more than a radial tyre, as the cross-plys don’t offer as much stiffness against centrifugal forces. A typical crossply tyre is likely to expand by around 10mm at 100mph.
The other variation of cross-ply tyres is bias-belt tyres, which are essentially a cross-ply tyre with additional belts (usually carbon kevlar) in the central section of the tyre to support weight. They’re still a standard fitment on some Harley Davidsons and are popular cruiser motorcycle tyres. You can tell a bias-belted tyre by looking for the letter ‘B’ in the tyre name.
Some tyres like the Metzeler Roadtec or are available in a radial fitment and a crossply fitment.
If you are in any doubt as to the best tyre for your motorcycle, give us a call on 0207 205 2205.
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