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Mind Those Hoops!

If your bike's been laid up over winter, here are a few things to think about regarding your tyres when you wheel it out for spring.

Last year we covered the issue of tyres that have prematurely aged due to winter storage conditions. It seems many riders don't even know that tyres have a 'shelf life', let alone that the way they are used (and stored) can shorten their useful life considerably.

All modern tyres have their 'birth date' on them. In the picture below, the 5016 set in a circle shows that the tyre was manufactured in week 50 of 2016, so the second week of December.

Manufacturers advise tyres are usually good for five years from manufacture then will require annual 'professional inspection' up to ten years. At which point they have officially had it. But, as we found last year, sometimes tyres will 'go off' even earlier than five years, particularly if they've gone through a lot of temperature variation and unheated storage.

If you're dragging the blanket off the bike and getting ready for the riding season, it's something to think about and check for. Along with a few other issues. Here's a short checklist:

1. Flat Spots: 

If the bike has sat on its tyres all winter, you run the risk of flat spots. Tyres will lose pressure over time, but the amount varies. If you've lost a lot of pressure a pronounced flat spot could result. Just before checking the pressure, put a little chalk mark on the sidewall pointing to where each tyre has been in contact with the ground. You or your tyre dealer might find it helpful later.

Next, check pressures and inflate if needed, as below.

Now roll the bike around a bit, feeling and looking for any obvious flat spots. If you find one at this stage the prognosis might not be good. It could be a forever problem, with the tyre needing to be replaced. But don’t panic just yet. Inflating the tyre to its maximum operational pressure (usually given for two-up with luggage in the manual) followed by an extremely careful ride that gets the tyre fully warm might get it out. Just be sure to park it so that those chalk marks are not pointing to the ground again.

If nothing shows up wheeling the bike around, you might detect a flat spot on your first ride. It will show up as a vibration and could be more or less pronounced during acceleration or braking. Bad front vibes can lead to head shakes, so be careful.

It can take a couple of longish rides to work out whether a flat spot will go, and you need to be really cautious. A flat-spotted rear tyre can work the shock hard and be prone to locking up under hard braking. On the front it’s even worse because it can cause instability, contributing towards a tank-slapper.

So go easy and be honest with yourself: have the flat spots gone for good? If not, it’s simply not worth avoiding replacement. Brand new tyres will give an immediate lift in performance, confidence and riding enjoyment. Not to mention safety.

2. Condition:

Storage over winter can affect tyre condition in ways that are obvious to the eye, such as cracking on the sidewalls. It would be unusual, and the tyre would almost certainly have been on its way out anyway, but if you spot any cracks or other defects appearing anywhere on the tyre it’s replacement time.

Another aspect of condition is not visible, and it's the one we talked about last year: tyres going off. Heat cycles are really important when it comes to motorcycle tyres. The technology that goes into making modern tyres such wonders in terms of grip, wet grip, warm-up and wear is complex chemistry. A tyre will only have so many heat cycles in it before its performance is compromised, as the oils, silica and other components stop working properly together.

Track use puts a lot of big heat-cycles through a tyre but it also wears tyres out very quickly. On the road that’s not the case, especially if you don’t do a lot of kilometres each year. Putting the bike away in an unheated shed or garage will mean plenty of heat cycles and sometimes exposure to extreme cold for long periods. And it can kill tyres.

Without riding the bike there’s only one way to tell if the tyre is cooked and that’s with a durometer, consulting the manufacturer’s spec. A specialist motorcycle tyre dealer should be able to do this for you but, even so, a tyre might be within its rated tolerances and still feel horrible.

A ride is the acid test. But, again, be cautious. The tell-tale signs are a lack of feedback, the tyres feel ‘hard’ or ‘wooden’ despite being at correct pressures and up to temperature, and a lack of grip. In rare circumstances a tyre will improve but you’ll need to do at least 30km, get the tyre good and hot then let it cool down for about 24 hours before trying again. If there’s no difference after two attempts the tyre is toast.

3. Wear:

It might easily have escaped your attention, or your memory, that the tyres were pretty much shot when you put the bike away for winter. Take this opportunity to give the tyres a critical check for tread wear and any problems with the surface. The legal minimum is 1.5mm tread depth in all the principal grooves of the tyres, around the complete circumference of the tyre. The principal groves will have wear indicators: a thin rubber flap across the groove at 1.5mm height. If the tyre surface is flush with even one of them it’s illegal.

As you go around checking the grooves, check the surface too for any cuts or anything embedded. Small objects can be levered out but if you find a screw or nail you’ll need a professional puncture repair.

4. Pressures:

Air will find its way out of a tyre over time, whether permeating through the tyre itself or via the rim seat, tyre valve seat or the actual wheel material. Nitrogen may not permeate through the tyre but it’s just as susceptible to other leaks. So, after storage, your pressures will likely have gone down. If there’s a big discrepancy between the two tyres, have a really good check for a potential slow puncture. If you cannot find and fix it, book it into your tyre dealer.

You might need to remind yourself of the recommended pressures in your manual, at least as a starting point. If your pressures are well short of recommended–say less than 26psi–inflate them first rather than ride down to the servo. A small battery-operated compressor is a worthwhile investment and great to take with you on road trips.

With winter over, some great riding lies ahead. Tyres play a critical role in how a bike feels and responds, so if you harbour any doubts about yours the sensible plan is to treat yourself to a new pair. Then look after them like the precious things they are.

The official motorcycle ‘Michelin Man’ dishes advice on tyre ageing.