How to check if your tyres are legal

  • Lily's Avatar
    Community Manager
    Hello everyone! 😊

    We’ve seen lots of questions about MOTs in the Community lately, so I thought it would be a good idea to share some top tips on how to check if your tyres are good to go

    1. Give the tread a quick check

    The law says your tyres need at least 1.6 mm of tread across the middle three-quarters. The easiest way? Grab a 20p coin. Pop it into the grooves: if you can still see the outer rim, your tread might be too low. Time to change those tyres.

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    2. Look at the sidewalls

    Any bulges, deep cracks, or cuts? That’s a no-go. Tyres in poor condition can fail an MOT and are dangerous to drive on.


    3. Check the age

    Tyres don’t last forever. There’s a little four-digit code on the side (something like “2319” — meaning week 23 of 2019). If yours are getting close to 10 years old, it’s definitely worth replacing them, even if the tread looks okay.

    4. Make sure they’re pumped up

    Under- or over-inflated tyres aren’t just inefficient, they can also be illegal if they’re not fit for the road. Check your car manual (or the sticker inside the driver’s door) for the right pressures.

    Still unsure? This quick video will walk you through it step by step: How to check if your tyres are legal.


    How often do you check your tyres?
    Lily
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  • 17 Replies

  • olduser's Avatar
    While you are checking - look to see if one side of the tyre is wearing more than the other, if so it can mean the wheel alignment is incorrect, call in at a garage or tyre depot who can check the alignment, and reset if required.

    You can also see if you have been looking after your tyres while checking tread depth - if the outer edges are worn more than the middle, they are running at too lower pressure but if the middle is worn more than the edges suggest running at to higher pressure.
  • Drivingforfun's Avatar
    I did a track day recently - my first in my own car

    I started with a legal tyre that I thought I'd "use up" before changing and had to cut the day short as I didn't realise just how quickly the tread goes down

    The first one isn't a "before" pic, they're both after, it's just to show how the tread pattern should look!
    Attached Images Attached Images   
  • olduser's Avatar
    Interesting - what made you look? Do you go around a lot of roundabouts?
  • olduser's Avatar
    Sorry Drivingforfun, I was interrupted on the last post.

    I hope you enjoyed exploring the limits for a while.

    I was assuming the 2nd picture was from the front, nearside front tyre, looks to be worn tapered, more on the outside than inside.
    A tyre man I once knew called it the Milton Keynes syndrome. 😎

    If not, is the wheel alignment slightly out?
  • NMNeil's Avatar
    I just checked the tyres on my truck, and the good news is there's one on each corner, so perfectly legal here in New Mexico 🤣
  • olduser's Avatar
    I just checked the tyres on my truck, and the good news is there's one on each corner, so perfectly legal here in New Mexico 🤣

    Not sure why but it makes me think of;

    https://youtu.be/iGCNBdCvzL4

  • Nick's Avatar
    Community Manager
    It can be really easy if you're not in the habit of noticing wear on the passenger side of your vehicle, as you don't see that side as often as you do the drivers side, so always worth checking.

    I once dealt with a claim where the insured had written his car off and our inspection noted that the tyres were down to tread in places, likely being a causing factor of the accident. The inspector noted that the tyres had likely been wheel-spun on a gravelly road or similar surface - claim was rejected. All insurance companies will have a clause around maintaining your vehicle in a "roadworthy condition"
    Thanks,
    Nick


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  • Lily's Avatar
    Community Manager
    @Drivingforfun do you drive competitevely? 🤔

    @Nick good to know, now I need to check my tyres.

    I read somewhere, maybe in The Times (when people say this, I can assure you they saw it on social media 😅), that wet grip rating is such an underrated part of tyre safety. It basically tells you how well your tyres perform in the rain, rated from A (best) to E (worst).Remember we were talking the other day about tips to drive in the rain?

    At 50mph, the difference between A- and E-rated tyres can be up to 18 metres!!! that’s roughly four car lengths! 😳 Even just one letter difference can add around 2.5 metres to your stopping distance. That can be the difference between life and death, right there.

    Were you guys aware of this?
  • Drivingforfun's Avatar
    I thought tyre tread is almost all about wet grip?

    Dry and wet performance is the compromise because by removing surface area to create channels for water, you take away some contact area with the road - i.e. grip in the dry

    In ideal dry clean conditions, no tread at all is best - by which I don’t mean bald old tyres but tyres which were manufactured as slicks
  • Drivingforfun's Avatar
    @olduser

    Thats the passenger side front tyre

    It started the day with a few mm of tread - it wasn’t matched to my driver side tyre as that was replaced when my car was fixed after a minor accident

    I decided to use the tyre up on the track rather than throwing away a tyre with a couple
    of millimetres of legality left
  • olduser's Avatar
    I thought tyre tread is almost all about wet grip?

    Dry and wet performance is the compromise because by removing surface area to create channels for water, you take away some contact area with the road - i.e. grip in the dry

    In ideal dry clean conditions, no tread at all is best - by which I don’t mean bald old tyres but tyres which were manufactured as slicks

    Your correct but;

    First the groves, in a tyre tread doe's reduce the contact area but to a small degree this is compensated by increasing the contact pressure. (smaller area same vehicle weight = higher contact pressure)
    Another effect is, the remaining blocks of tyre in a tread tend to flex as the vehicle steers, brakes, or accelerates, the deeper the tread the more the flex.
    Flex = heat = higher wear rate.

    In the dry used tyres are faster (not much) when timed on a track but there has to be sufficient 'rubber' left for it to work, (the 'rubber' has to be thick enough to mould around, and into the road surface for grip?) we found tyres with most of the remains of the tread pattern visible were best, if the pattern had gone the remaining 'rubber' was too thin. (the tyre structure under the 'rubber' will not yield, and stiffens the surface?)

    Common sense suggests, the edges of the tread pattern ought to contribute to grip but all I can find adds up to, only while the edges are sharp - they quickly round off - and the extra grip is very small.
    Interestingly, wet tyres in racing, are effective while the edges of the tread pattern are sharp once worn, the water in the grove can form a sort of water wedge between the road surface and tyre, not good.
    Ah, so that's why they change wet tyres when they still look to be OK!

    What is the 'best' tread pattern, well how long is a piece of string?

    In the Wet, we want high contact pressure to expel the water with wide channels to let the water escape to the back.
    For Mud and snow, the groves need to be tapered to clear, the tread also needs to trend towards a paddlewheel for them, similar but less so for gravel and sand. Ice, well short of steel spikes, reduce the contact patch to increase the pressure, there isn't much can be done.
    For dry roads we want as much rubber as we can, and amongst all this, we want it to be quite!

    Why do drivers drive on illegal tyres, we have all passed the car in the carpark, and thought, the stupid idiot!
    My thought is, for what it's worth.
    Ironically, we, he, she, adapts to the lower grip, aggressive drivers are better at this than the rest of us they are juggling with grip more.
    We brake earlier and longer to compensate for the lower grip.

    In the end, it is the law, we have to change our tyres at 1.6mm. (which is a very good compromise figure)
    Last edited by olduser; 10-10-25 at 14:57.
  • olduser's Avatar
    @Drivingforfun do you drive competitevely? 🤔

    @Nick good to know, now I need to check my tyres.

    I read somewhere, maybe in The Times (when people say this, I can assure you they saw it on social media 😅), that wet grip rating is such an underrated part of tyre safety. It basically tells you how well your tyres perform in the rain, rated from A (best) to E (worst).Remember we were talking the other day about tips to drive in the rain?

    At 50mph, the difference between A- and E-rated tyres can be up to 18 metres!!! that’s roughly four car lengths! 😳 Even just one letter difference can add around 2.5 metres to your stopping distance. That can be the difference between life and death, right there.

    Were you guys aware of this?

    Did I drive competitively? No, we raced each other on fields or an old aerodrome, and I went to another old aerodrome that had club racing events and helped in the pits if I thought I could help, (in those days most entrants drove their car to the event, with only a few bringing their race car on a trailer) payment would be a few laps, or maybe drive in the all comers race at the end.

    But we had a little group that were always interested in checking (as best we could) did our modifications make things any better?
    My first tuned Mini sounded good but was no better on the track, then it dawned on me upping compression ratio, and improving gas flow needed a different ignition advance curve! In fact the standard distributor was over advancing at higher revs, springs from a Cooper S distributor solved that, meanwhile SU (carburettors) suggested a needle and loaned me a few either side to try, this was helped along because one of the guys got one of those glass spark plugs lets you see how the mixture was burning.

    Happy days!

    Wet rating A - E but when, new, middle aged, old? Yes there are winter tyres (are they compulsory in the EU?), and if you change onto them in the wet they are noticeably better but after half an hour you learn to exploit the extra grip, putting you back to square one!
    Last edited by olduser; 12-10-25 at 15:23.
  • Lily's Avatar
    Community Manager
    @olduser when was this? Sounds really, really fun. I was never that cool in my twenties, my friends and I used to go to the movies and maybe concerts. Well, we were a group of musicians (have I mentioned I played the violin as a kid?) and I think only one of us owned a car.

    Do you have any pics of the modified Mini? 😎

    I think definitely new (tyres). I had no idea either this existed until recently.
    Last edited by Lily; 13-10-25 at 06:02.
  • olduser's Avatar
    @olduser when was this? Sounds really, really fun. I was never that cool in my twenties, my friends and I used to go to the movies and maybe concerts. Well, we were a group of musicians (have I mentioned I played the violin as a kid?) and I think only one of us owned a car.

    Do you have any pics of the modified Mini? 😎


    I think definitely new (tyres). I had no idea either this existed until recently.

    I couldn't afford to run a camera and a car! 😃
    I had not been working long, when I got my first Mini, private sale the owner had died and no one in the family wanted it, back then Minis were thought to be worthless, 'who would buy a second hand toy car?'

    Motorbikes and cars used in fields were other peoples cast offs, usually due to rust but some were revived by swapping bits around.

    We learned initially by building bicycles from parts found on the local tip, to use on a bicycle version of speedway.

    We got the idea from the local village shows, there would be the usual show jumping for horses and cycle races on grass, these guys would go around shows in the season.
    One man who lived in Howden (East York's where I originate from) who did this, his day job was painting road signs, of course he cycled to his work which covered a large area.

    His grass track bike had bamboo wheel rims!

    He would carry-on painting road signs or cleaning (like the forth bridge, when he reached the last one it would be time to start again) but still talk about racing, he could remember details of races from years back.
    He showed us how to pack tyres with grass if we were caught with a puncture and no repair kit, he also taught us how to get a tyre off and on without tools.

    We had two great years with the bikes, it had been planned to turn a local road junction into a large roundabout but the work stopped when they were ready for the road surface, leaving a nice sand base for us to race on, there were two school summer holidays while it was stopped. (I think there was a dispute about who owned the land)
    Who said, we had to die to go to heaven?
    Of coarse this would be mixed in with piece work on farms, pea picking, potato harvest, and maybe grain harvesting.
    Bramble picking (for shops or for ink manufacturers) and wild rose hips (for Rose Hip Syrup production commercial or home)
    When the local Fair came along, free tickets could be earned by collecting, and washing bottles from the tip, for the shooting stalls, or jam jars for the gold fish prizes.
    Amongst us all year round, would be paper rounds, grocery delivery, butcher delivery.

    The only screens we would see would be in the cinema, when we could afford it, though, there was a small door got you in behind the screen but it wasn't the same as being front of house, behind the screen was a bit fuzzy, and I think the space was about 6 - 8 ft wide, so if you could see the action on the left you missed it on the right! Top of the screen, no chance, and it still didn't answer the big question - what happened when the bedroom door closed, (and we were on the other side?) and/or the waves beat on the shore -

    Of course the owners of the cinema were not happy, if they caught us there.
  • Lily's Avatar
    Community Manager
    @olduser I could only afford the camera -barely!- so I completely understand. What year are we talking about?

    I can't believe Minis used to be considered worthless, crazy.

    "He showed us how to pack tyres with grass if we were caught with a puncture and no repair kit, he also taught us how to get a tyre off and on without tools."
    --- this sounds extremely useful!!

    The cinema, the fair, the bramble picking, all reminds me of reading "the Famous Five" with my mother when I was a kid. She even had a dog called Scamper! I was always trying to get my friends to have "adventures" (go camping, organise our own fair or summer party) after I read them all but it only worked a couple of times. It seems you had a great childhood!
  • olduser's Avatar
    Though I thought they were very good automotive engineering for the time, they were not popular or appreciated until they became fashionable.
    I think, in the main the problem was the press releases said things like, "economical", "cheap", and "small", certainly in 59 and 60 not good selling points.

    Yes, looking back, as children my friends an I had an almost idyllic childhood. We were out in the country, and were able to roam, build camps, climb tree's to navigate the camp over the four seas or fly to the ends of the earth. And I think, because most of the parents livelihood depended on the land, we avoided doing damage. If we dug up a potato, we would cover up the remainder to stop them being spoiled.

    The war to us, was convoys of lorries with men in uniform who sometimes would throw out chocolate, chewing gum, or army rations.

    We were in the flight path for a relief air field, (the one we played on after the war) I can remember watching bombers flying over, looking to see where they were when the wheels disappeared, so I could go to find the wheels, and have the best wheels on my kart (better than pram wheels!) to race down the nearby railway bridge. I never found any?

    And of course, we played Cowboys and Indians, many a time we have been surrounded under what cover we could find, and had to shoot our way out until our fingers were red hot from firing so many bullets or we got tired of shouting, Bang!

    But we were learning - as you climb up plan your way down. Don't go looking for a fight, they will come at you fast enough anyway, and no one really wins in the end, there is always a cost.
  • Rolebama's Avatar
    I bought my first Mini in 1969. I would buy new parts for servicing and anything relevant to suspension, steering and brakes. But for almost anything else it was a trip to the breakers. On one occasion, I picked up a complete Mini for £15, with nothing major wrong with it. I wanted wiper mechanism and motor, which with blades and arms would have been more than £14 new! I sold the engine and gearbox, rear subframe and the wheels and tyres for around £40 total. Then had a scrap man take the bodyshell away. Used cars were cheap as chips then, as well as motorcycles. I paid £10 each for my three A10s, a Royal Enfield Constellation, AJS Model 16, Rare Ariel Square Four 600cc, and from £0 to £5 for umpteen Bantams and Francis Barnetts to run around the fields. I used to do competition Trials in North Wales on a Greeves Scottish and a Triumph Mountain Cub in the late 60s at a total purchase price of £7. Also did Clubman Motorcycle racing at the same time on one of the A10s. Great fun.