Are My Knobbly Tyres Illegal ?

Here's a popular question about "Knobbly" Tyres : I was riding a road-legal off-road bike, along with a group of friends, on green lanes. I know we are not popular with the locals, who are unable to distinguish between us and illegal tearaways on motocross bikes. Our papers have stories every summer about crackdowns of "off-road motorcycle riders". My bike has an MoT, a road-legal exhaust and a registration number. It is taxed, and I wear a road-legal helmet. Sure enough, when my friends and I were pulled over by a particularly agitated police officer his computer check revealed that our bikes were all taxed, insured and ridden by their registered keepers.

But then a police sergeant turned up, who proceeded to give our bikes a roadside MoT. I was told that I will be prosecuted, along with a couple of my friends, for riding on the road with "knobbly" tyres. My bike hardly ever goes on the road. The only roadwork it does is between green lanes, usually on pretty badly beaten up country lanes liberally spread with gravel and a fair spread of cow and horse deposits.

Of our bikes, three of us had tyres marked "Not for road use" and a couple of the other lads were found to have tyre pressures that were below the recommended level for road use. We have all been summonsed to the local magistrates’ court, and we expect to get an unsympathetic hearing from the landed gentry, busybodies and bored ex-army officers who seem to make up the magistrates’ bench. I cannot see that I have done anything wrong. Should I expect to be convicted?


I Like to give straightforward answers to straightforward questions, but on this one I am struggling. Your summons is for the use of the tyre, contrary to regulation 27 (1) (a) of the 1986 Regulations. The prosecution has to prove that the “tyre is unsuitable having regard to the use to which the motor vehicle... is being put”. I ride a green-lane bike in an area where off-road riders, whether legal or not, are met with universal loathing. I understand the dilemma you are in.

I would be putting forward a defence that the Crown has failed to prove that the tyre is unsuitable for the particular use that you were putting it to – but going to court is my job, and you might not be so confident. As you said, your bike is used predominantly for riding on unmade roads, green lanes, mud and grass. Your tyres are entirely suitable for that type of terrain.

Honestly, I cannot tell you whether or not a local bench will find in your favour. The police do not make any allegations that you were riding fast or anything other than carefully, so riding slowly and sedately on tarmac on an off-road tyre does not strike me as an unsuitable use of the tyre.

Unluckily for you, the chances are pretty slim that you’ll get even one magistrate who understands the technical requirements of an off-road tyre, the fact that you’re putting your tyres through no strain while riding for short journeys on tarmac, and also that off-road tyres should be run at a lower tyre pressure (indeed there is law on this point – the tyres can be at a pressure that is suitable for the tyres’ use at the time [Conner v Graham 1981]), even if they go for short periods on tarmac. You must make sure you have expert evidence from somebody who can give it about tyres – or if that is impracticable or too expensive then published works, such as off-road riding guides, would at least raise reasonable doubt in the magistrates’ minds.

Keep your observations to the facts and do not become aggrieved or shouty – a presentational disaster. This may be the kind of case where professional representation would be money well spent. On your own, I think you will be in difficulty.