tincaman
Guru
- Location
- Chudleigh, South Devon
Couldn't see any anything that would put me off spending 12.99 on them. What you got
The tyre’s ride quality, which is exceptional. It is best enjoyed on rough, broken tarmac, over which the suppleness of the carcass allows the tyre to float in the manner of a roughly equivalent (say 24mm) cross-ply tyre inflated to about 0.7 bar or 10psi less. There is some comparative reduction in rolling resistance over such surfaces as the tyre comforms more readily to the surface. For sure, over the poorly-maintained lanes of the Surrey Hills, the Radiale rolls very nicely.
Inevitably, however, there is a caveat – and a big one at that. Let’s start with the observation that it is illegal to drive a motorcycle with a radial front tyre and cross-ply rear. Same with a car, for that matter. A radial tyre’s carcass has less inherent lateral stiffness and requires stiffening belts under the tread to provide the required steering response and precision. Without them, a motorcycle with radial front tyre and cross ply rear would understeer – run wide – dangerously.
Now, the first time I rode a pair of Radiale clinchers, I arrived at my destination in a state of nervous exhaustion. My first act on getting home was to take them off and it was only after some reflection that I gave them the longer trial they deserved.
Why? Because the radial carcass offers a fraction of the lateral stiffness of a cross-ply. This can be demonstrated by applying pressure to the sidewall of the inflated tyre; where a cross-ply barely moves and the pressure appears to act on a section of tyre extending either side of the point it is applied, the radial carcass simply gives way at the point of pressure to an almost amusing degree, leaving the section of tyre just 30mm either side unaffected. Said a mate who tired it; “It feels like a rubber snake.”
So what happens is that the tread, which grips the road surface, is less directly connected to the rim by a radial carcass. Because the tread can move sideways to a greater degree relative to the rim, the tyre conveys less immediately the lateral force generated by the tread when steering. This force is transmitted via the spokes, hub, fork legs and so on to the handlebars and, essentially, tells the rider how much grip is available.
The Radiale front tyre conveys the sensation of riding on a surface with significantly less grip than is, in fact, on offer; it’s like riding with a greatly under-inflated cross-ply. Try riding on a regular clincher inflated to 60psi (0.5bar) and you’ll get the idea.
If the effect is unsettling when riding in a straight line, it is downright unnerving when it comes to corner entry, where that sense of uncertainty makes it hard to judge line and apex even in the dry. Until you get used to the feel of the tyres, that is. This takes some doing.
Once well-acquainted with their unique feel, the Radiales are, in fact, perfectly useable. The tread, which uses Vittoria’s Isogrip compound, is perfectly grippy, so once laid into a corner the tyres stick as expected, provided you don’t try to change line part way through. One way to improve cornering still further is to over-lean by pushing the bike inside the rider’s centre line; this reduces the height of the inside sidewall and dials in some useful oversteer.
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