Monday, January 13, 2014


"There comes a time," the Walrus said...

As far as motorcycle tyres are concerned, the time for replacing these hoops of expensive rubber comes with alarming frequency. Expect perhaps 8000km from the rear tyre of a large and powerful motorcycle: something to do with pushing  100 horses through an area of around eight square inches.

The best tyres for my Kawasaki 1400GTR are, according to motorcycle forums, Michelin Pilot Road. Alas, the local UAE Michelin importer doesn't bring in motorbike tyres. The Continental Tyres shop didn't have any suitable tyres in my size, nor did the salesman fulfill his promise to phone me when he found out if my tyres would ever be available. Short of personal mail order via Aramex Shop 'n' Schlepp, which is likely to be horribly expensive and subject to 5% import tax, I'm left with the option of scouring the local tyre shops.

Over at Liberty Automobiles, where the Kawasaki workshop lives, I was advised that it would be cheaper to obtain Pirelli tyres from the importer rather than through Kawasaki. I found a pair of Angel ST in my size.

Well, actually, the rear tyre isn't the correct size. It's a 190/55 rather than Kawasaki's recommended 190/50. But the forums (again) report that some riders prefer the taller profile. Anyway, in December I bought the last pair in the shop and took them home. I then proceeded to wear out the old Metzelers.

Almost as bald as Yul Brynner's
glabrous twin brother
By the time January came around, the old front tyre was pretty much shot. Even though there was still some life in the rear, I changed both because messing with different brands on the same high performance machine may be asking for all manner of unpleasant handling surprises.

In my GTR, all previous tyre sets have made the bike corner in the same characteristic way. When leaning into a bend, the bike wants to stand up, and it requires a gentle push on the inside handlebar to keep it leaning at the correct angle. As the front tyre wears, its profile gets more pointed, and the rear profile gets flatter. The profile mismatch makes this standing up progressively more pronounced.

Angel on the front
Angel on the rear
The first thing I noticed with the new Pirelli Angels is that the bike was much easier to tip into a curve than the previous set. I accept that I'd gradually got used to how the bike behaved on the previous tyres, and this was the shock of the new, but the way that the bike now holds a constant lean angle in corners with no steering input from me was new, and a very pleasant surprise. Steering is now totally neutral. My guess, and it is a guess because I don't have a PhD in motorcycle chassis design, is that the taller rear tyre more closely matches the profile of the front.

A useful side-effect of the larger diameter rear tyre is that the speedometer no longer over-reads, and an unexpected bonus is that the bike's easier to put on to the centrestand.

Pic from Fast Bikes magazine.
Obviously not me. 
And it still fits under the rear hugger mudguard. All in all, a success. I'm hoping for long tyre life as well as the promised super grip, but I fear that these features are mutually exclusive.


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