James Whitham Column - Mar 2008

Professor James Whitham, ASF, J.BAC, has been conducting scientific experiments over winter with his 29 year-old GT250 and some isobutylene-isoprene copolymer...

Posted: 12 March 2008
by James Whitham

Until recently it’s been a fairly warm winter, well up north it has anyway. Consequently I’ve been doing more road miles on a bike than I normally would at this time of year. The road bike I have in my garage at the moment is a 2007 Z1000 and while I’ve really enjoyed dodging about on it all through the summer I’ve found it more difficult to feel confident on it now the roads are constantly wet and greasy.

Years ago, when I was in my teens and riding bikes through winter everyday I can never remember being so concerned with the lack of grip and it started me wondering what had changed. The main difference would be the bikes. Back then I’d have been on a two stroke with crap suspension, skinny tyres, wooden brakes and about a quarter of the power that the Kawasaki has. And protective riding gear would’ve consisted of an ill-fitting polycarbonate lid, a Harrington jacket, and a pair of Doc Martin boots. So why did I have more confidence in these sort of conditions back then ? Is there something about the old type bikes that make them easier to ride when there’s less grip, or is it simply me that’s older and more sensible than I was ?

To put my mind at rest I thought a little test was in order. Even though at the first sight of a salty road I knew there was a serious risk of the thing dissolving I’ve been out on a 1979 Suzuki X7 I’ve had for a while. Even with the stone-age suspension, as soon as I set off on it I felt like I had more feel for what the tyres were doing and how much grip there was or wasn’t. I could lean further over on the roundabouts without feeling like I was going to flop onto the road and could set off from traffic lights without the rear tyre spinning.

I’ve been thinking about it and obviously one of the reasons for this is the difference in power. The Zed has 125bhp available compared to the X7’s 28, so you don’t have to be as careful when you open the gas, but I’m convinced the main factor is the tyres. Not so much the compound but the actual shape and amount of rubber that touches the floor. On warm, dry roads when they’re up to working temperature there’s no doubt that the Kawasaki’s wide, low profile sports rubber would develop enough grip to bend the little Suzuki in half. But on wet, greasy, winter roads I never feel like I can get enough heat in ‘em to get them working properly.

On the X7 the 18 inch cross-ply tyres are less than half the width. This gives you a much smaller contact patch that is forced harder onto the surface of the road. So when the grip levels are way down you have more feel, even though they’re probably the same compound as Bakelite.

The party season has come and gone without as much collateral damage as usual in the Whitham household. Apart from getting a bit out of shape on the Friday before Christmas there wasn’t much silliness at all. The idea was to have a small “drinks and nibbles” party with a few friends and family calling round from 5 o’clock onwards for a glass of mulled wine and a mince pie. “People will call on their way home from work” said Andrea. “Everyone will have gone by 10 o’clock” she said. To be fair I can’t blame her entirely for what ended up being a full house full on piss-up. It started going wrong for me fairly early in the day. I’d been out for a mountain bike run and was feeling pleased with myself when I made my fatal mistake. “Seeing as it’s Christmas let’s call for a swift one at the Farmer’s Boy” said my mate Johnny.

Two hours and four pints of Stella later we wobbled out of the pub wearing Santa hats. It became apparent immediately neither of us would be riding our bikes home. It took me three laps of the car park to find mine. I finally stumbled in at about three and was as much use to Andrea in sorting the house out as a chocolate teapot.

When the guests did start arriving we realised we’d invited loads more people than we thought. We ended up with a proper house full and by the time we’d got rid of the last one it was after 2am. Another partial success I think !

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