Rubber: why you should look after your tyres

When was the last time you took a long, considered look at your tyres? Yes, it's been a long time, hasn't it? You already know that your motorcycle's tyres are probably the most crucial component of its handling. If you're riding around on a four-year old Pulsar with 25,000-km old tyres, you really are wasting away. Indian tyres have a design life of about 35,000 km. Which is one of the reasons why they aren't very sticky and even relatively cheesy tyres like Shinkos and Duro's feel better to ride on. By 25,000 km, they've probably lost their original contour, hardened (lost grip) and in general are functional, but well past their best.

Usually, a weekly pressure check (remembering to vary the pressures as per manufacturer recommendation whether you're riding solo or two-up) is about all that is needed. However, once a month, you should ideally pull up a stool and sit down next to the tyres and take a long look at them. First, look at the tread. Start out by looking for foreign matter. You will find stones, pebbles and all stuck in the tread. Take a screwdriver and gently eject these. Remember to temper your force, you don't want to damage the tread block.

Second, look for tread block damage. You're looking for spots with excessive tread wear (locked the rear badly lately?). Bad flat spots will be susceptible to punctures, and will cause vibration. If you ride hard, keep an eye out for longitudinal cracks and tears that may have been caused by riding over a nail, while tore up the tread for but didn't get to the tube. Badly damaged tyres should be replaced pronto. Tread blocks can also be broken (shattered leading edges), uneven (one of the edges is less worn than the other)... It goes without saying that you're tyre's gone bald or squared out, it need to be thrown and replaced with a fresh one. You will be amazed at how much difference it makes to the handling of your bike.

My first RD came with a worn rear tyre and I rode it because I was running in the engine. I kept wondering why people were singing praises of this stupid motorcycle. Then one day, the engine loosened up and power went up. Next payday, I went and got fresh tyres spooned on. Best 1500 bucks I ever spent. It cleared up exactly why the RD was considered great on the handling front. My first high-speed wobble came much later, of course, heh heh.

Once you've given the tread a detailed once over, look at the sidewall and the slightly exposed part of the beading. The sidewall should look fresh and supple. If you can see cracks (normal if you've had the bike awhile but it doesn't get ridden too much), it's time for a new tyre. The cracks develop as the tyre hardens. At this point, your tyre is more or less useless. In bad causes, the pressure in the tube will punch through the sidewall and make it look like it has goitre (don't ask how I know). Think of sidewall cracks as a minor emergency, it's that serious. The beading should sit evenly around the rim and not be frayed. Sometimes a fast puncture-walla will manage to dig his screwdriver (since they never have tyre irons anyway) into the bead. In time, the rubber will get scraped away allowing the structural wires and thread to start peel off. This is rare, but weakens the tyre-rim seal and the tyre should instantly be discarded.

The final check, of course, is to see that rim (especially spoked steel rims) are running true and that both wheels line up properly. First part is easy, hold a screwdriver so that end is close to the rim, and the rest of it rests firmly against a fixed bit (like a fork leg or the rear shock). Spin the wheel, and look at the distance between the screwdriver tip and the rim – it should be constant. While there are involved wheel alignment tips, but I simple walk away from the bike with the handlebar straight and then kneel and look at the bike from a distance. It should look straight, and in most cases, unless you've had a serious crash, it will. If you think one of the wheels looks askew, start by checking if the handlebar is straight (perpendicular to chassis) and not bent out of shape. Then look up one of the detailed alignment discussions and figure out if the chassis is bent. Front forks can be kicked back into alignment – a crude way to do it, but it works.

All of this takes about half an hour on a Sunday morning, but is well worth the effort. Michelin has a fairly comprehensive section about tyre tips here.