when should you change tyres? - Mr Carrot Cake

I have one tyre that has a DOT code from 2010 and slight cracking in the tread. Is it still ok to use or would you guys advise changing it? Tread still has 5mm.

when should you change tyres? - scot22

I am neurotic : I would change it if I had any doubt. Stress I have very little practical knowledge ( others will give more qualified advice ) I suggest if you ask then you must be uncertain.

when should you change tyres? - FP

Tyres do deteriorate with age and the effects of sunlight. If there is cracking in the grooves of the tread or on the sidewalls of the tyre I suggest it is changed immediately, irrespective of the amount of wear.

when should you change tyres? - RobJP

Agreed with the previous 2 posts. If any doubt at all, get it changed.

As an aside, most tyres start with 8mm of tread. The legal limit is 1.6mm, but you really have minimal grip with 2mm remaining. I change tyres when I hit about 3mm, as grip greatly diminishes from 3mm to 2mm.

So looking at it from the positive side, you've had at 50-60% of the 'good' wear out of the tyre.

when should you change tyres? - Engineer Andy

I'm not any technical expert about such things and as such always defer to caution as other posters have said - I changed my OEM-fitted Bridgestones on my Mazda3 after 6 years even though they had 4mm (front) and 5mm (rear) as I recall, for similar age reasons and after one or two hairy moments in the wet. They also happened to be quite noisy as well. Glad I did - my new set of tyres were much better in all regards.

Better to err on the side of caution when it comes to safety with tyres. A car with an average NCAP rating and decent (reasonably new) tyres is probably safer (especially in the wet) than one with a 5-star rating and old/poor/worn tyres as the chances of getting into serious trouble is much reduced.

when should you change tyres? - RT

If it's cracking in the tread, change it due to poor condition.

I change mine at 3mm - below that and wet grip starts to tail off very quickly.

There are industry recommendations that trailer tyres should be changed within 7 years from their date of manufacture but they can spend long periods in one position - and anyway sometimes need changing before that due to cracks in the tread

when should you change tyres? - Smileyman

few years back dealer failed Mrs S's Mazda 2 (MOT) on the grounds that the the original fit Continental tyres had cracks in the tread (but not bald) ... they phoned and advised they could fit 'budget' tyres Maxtor (I think was the brand) for only £X.

Not knowing any better she agreed, but wisely called me to advise .. there were fireworks that afternoon and the car left the garage shed in brand new Continental tyres. Whilst cost is important, I didn't know the tyre in question so playing safe with known quality tyres is even more important.

when should you change tyres? - scot22

Reassuring to know that my attitude to tyres is backed up by others ( non neurotic people )

when should you change tyres? - FoxyJukebox

I always change the lot every three years--that is usually after about 25000 miles. No mucking about.

i also try and avoid a well known so called fast tyre fitter. they are over priced. A local man can always source good value, good quality safe tyres. Shop around then changing tyres doesn't become a stress purchase

when should you change tyres? - John F

I have one tyre that has a DOT code from 2010 and slight cracking in the tread. Is it still ok to use.........? Tread still has 5mm.

Yes, unless it has been internally damaged by a pothole. Five years is no age at all for a decent modern tyre. Slight superficial cracking is of no significance. My records show I changed my TR7's 1988 tyres in 2011. Apart from hardening up over the years with less grip in the wet they were still in perfect working order passing annual MoTs - I just fancied some new ones.

Doubtless this will generate the usual opprobrium from the usual dogmatists, some of whom are clearly interested in generating as much servicing work and expense as possible. So you should weigh up the pros and cons with whatever physical and mechanical knowledge you have and do what suits you. You could check it by inflating to its max tolerated pressure and look for bulges.

when should you change tyres? - RT

I have one tyre that has a DOT code from 2010 and slight cracking in the tread. Is it still ok to use.........? Tread still has 5mm.

Yes, unless it has been internally damaged by a pothole. Five years is no age at all for a decent modern tyre. Slight superficial cracking is of no significance. My records show I changed my TR7's 1988 tyres in 2011. Apart from hardening up over the years with less grip in the wet they were still in perfect working order passing annual MoTs - I just fancied some new ones.

Doubtless this will generate the usual opprobrium from the usual dogmatists, some of whom are clearly interested in generating as much servicing work and expense as possible. So you should weigh up the pros and cons with whatever physical and mechanical knowledge you have and do what suits you. You could check it by inflating to its max tolerated pressure and look for bulges.

It's not you that's taking the risk that your advice is plain wrong - the fact that you've "got away" with it doesn't mean that you or anyone else will continue to.

when should you change tyres? - Smileyman

@ John F "less grip in the wet" sounds like a good reason to fit a new tyre, think of other road users too.

when should you change tyres? - RobJP

You could check it by inflating to its max tolerated pressure and look for bulges.

You have written some nonsense in your time, John, but that really does take the biscuit.

Then again, you seem to do oil changes every decade or so, and have the only TR7 that hasn't rusted back into iron ore. So quite possibly it fits in with your usual postings !

Also, as Smileyman points out, a loss of grip from your tyres does kind of indicate that you might want to think about changing them. Or maybe that is a bit too 'dogmatic' for you.

when should you change tyres? - Avant

"My records show I changed my TR7's 1988 tyres in 2011. Apart from hardening up over the years with less grip in the wet they were still in perfect working order passing annual MoTs - I just fancied some new ones."

John - we've had this debate before, and I don't want it to get heated. But could I ask for your reaction to the following thought:

Your TR7 is presumably a fun car, which I imagine you use mainly if not always in the dry, and its annual mileage is low. I, on the other hand, have driven amost every day on wet roads in the last couple of months, given the current weather: and for my purposes 'less grip in the wet' would be dangerous, as however carefully I might drive myself, someone else may not be.

Would you be prepared to agree that, at least for a car used frequently, old tyres are a risk not worth taking?

when should you change tyres? - joegrundy

No wish to derail thread, but I'd be grateful for comments on my 'tyre dilemma'.

I run a 2004 Xtype 2.0d, bought coming up to 3 years ago on 130k miles, now coming up to 160k. (Paid £2700, now worth very little.) Serviced every 9 months or so by local trustworthy independent, very few problems, has averaged about 50 mpg, and old enough that I take the supermarket car park 'dings' in doors etc. philosophically (after an initial rant!). Live in rural west Wales, most journeys fairly short, but a 300+ mile mixed trip every few months, and at least once a year a 2500 mile round trip to Andorra incorporating 130 km/h autoroutes and rural mountain roads.

Was on 16" 205/55 until about 6 months ago, with mixed 'mid cost range' tyres as necessary. Then I bought from a friend a set of Jag alloys fitted with Pirelli P Zeros - 17" 225/45. (£100). (My 16" Jag alloys were quite shabby/corroded.) No doubt the road holding is better (though I rarely push the car hard enough to test it) but the ride quality is worse and mpg seems to be about 5 mpg worse.

The Pirellis will need changing in about 3 months and I am considering my options.

I could get my old 16" wheels refurbished for about £50+ per wheel and go back to 55 profile. Better comfort, cheaper tyres, better mpg, but not sure it's worth it in view of low value of car. Or new tyres on the 17" wheels.

In the past I've used the local branch of a national tyre fitter. No problems, but not cheap. Lately I had cause to check the 'Asda tyes' website (I didn't know they sold tyres). Good range at good prices. They use local firms to supply/fit. My local supplier is a small independent who I know well, and he tells me he can undercut the website prices by at least 10%.

To get my 16" wheels refurbished and reshod would cost about £400+, which seems to me to be an unwise investment in a car worth so little. Reasonable new tyres on the 17" wheels would be about £200. I don't need high performance, and I may not need longevity.

I think I may have answered my own question in the process of writing about it! But I'll post it anyway.

(Or would it be possible to change to 225/17 x 50 or 55 profile?)

Edited by joegrundy on 02/01/2016 at 09:39

when should you change tyres? - bazza

Whatever is the cheapest option and leaves you with most notes in your wallet! Surely it's pointless refurbishing wheels on a car that is woth very little. The £200 options sounds good.

when should you change tyres? - John F

Would you be prepared to agree that, at least for a car used frequently, old tyres are a risk not worth taking?

There is minimal 'risk' in this case and a car used frequently is unlikely to have tyres on long enough to get old.

The 'risk' is losing control through loss of adhesion. There is no appreciable risk of sudden 'blowout' from a pressure less than half that in my skimpy thin ancient bicycle tyres.

Most drivers are usually aware of roughly how hard they can steer or brake before their car is likely to skid. My TR7 is indeed a 'fun' car now, although not as much fun round roundabouts as it used to be! Even with new tyres its grip is still fairly poor by the modern standard of a fat flat wheel at each corner. I remember there was not a huge improvement with the new ones so the risk of slightly more slippery very old tyres was pretty small in my view; a view endorsed by the MoT inspection rules - age is not mentioned. So perhaps you should argue it out with those who set the MoT rules, not me. I just try to counter the pervasive expensive fear-mongering of the motor trade who, quite understandably, cause so much unnecessary expense for those who often can least afford it. (e.g. great aunt Minnie's annual 2000 mile oil changes).

when should you change tyres? - FP

I don't know if John F believes that tyres, if not worn out, can last for ever. That is pushing his argument to an extreme, of course.

Internet research suggests that tyres age from exposure to weather, especially UV radiation, but also from the action of gases in the atmosphere. Several times an age of four to five years is suggested as being the time when noticeable deterioration starts. One source suggests that tyre manufacturers treat ten years as the maximum life of a tyre, even if unworn.

Most drivers will take a common-sense approach to this. It seems to me that noticeable cracking is a sign of weakness in a tyre that may be more than superficial. I would always err on the side of caution. We are dealing with a component that provides (along with its fellows) the only, small contact with the road for a heavy and potentially dangerous vehicle. I would hate for that to be compromised.

when should you change tyres? - John F

I don't know if John F believes that tyres, if not worn out, can last for ever. That is pushing his argument to an extreme, of course.

I prefer the word 'thinks' to 'believes', which is not in my vocabulary. I think a tyre would indeed last indefinitely if in a dark vacuum. Conversely, a tyre exposed to the sun every day (like the one on my ancient lakeside dinghy trailer facing south - very cracked) will age far more rapidly than one kept in a garage most of the time (or in the shade facing north - no cracks!)

when should you change tyres? - Big John

Autoexpress article on old tyres

www.autoexpress.co.uk/car-reviews/38991/so-why-do-...s

when should you change tyres? - John Boy

6 years old, slight cracking in 5mm tread, replace? No way!

Clearly there are people on here with plenty of money.

when should you change tyres? - dimdip

Tyres for large aircraft often have a shelf-life of only one year, which indicates the potential rate of degradation.

when should you change tyres? - Andrew-T

Tyres for large aircraft often have a shelf-life of only one year, which indicates the potential rate of degradation.

Do you apply the same hazard assessment criteria to your car? Surely not?

when should you change tyres? - FP

'"Tyres for large aircraft often have a shelf-life of only one year, which indicates the potential rate of degradation."

Do you apply the same hazard assessment criteria to your car? Surely not?'

He wasn't suggesting that. He said, "Potential rate of degradation." The word "potential" suggests that there is some degradation to tyres after one year, which, as it continues, might become significant at a later point in tyres used in other applications.

when should you change tyres? - galileo

Tyres for large aircraft often have a shelf-life of only one year, which indicates the potential rate of degradation.

I thought it was usual practice to re-tread aircraft tyres a number of times, is this still the case?

when should you change tyres? - Andrew-T

Tyres for large aircraft often have a shelf-life of only one year, which indicates the potential rate of degradation.

I thought it was usual practice to re-tread aircraft tyres a number of times, is this still the case?

Shelf-life is one thing. What is the working life of an aircraft tyre - even after retreading, which I guess must happen quite often, seeing how much burns off at every landing ?

when should you change tyres? - RT

Retreaded aircraft tyres, and retreaded truck tyres, are designed for multiple retreading and all get a thorough examination both externally and more importantly internally.

With the exception of puncture repairs, when a good tyre fitter should carry out a thorough external and internal examination before repairing ( but many don't) - I doubt that any car tyres get removed from the rim for an internal examination.

So the comparison with aircraft or trucks tyres is little help.

UV degradation takes place all the time, except when tyres are stored in the dark - and oxidation takes place constantly unless hermetically sealed - and who does that?

when should you change tyres? - Engineer Andy

Maybe John F does - his garage maybe doubling as a lab for assembling satellites or PC motherboards when he's out doing 180s on mini-roundabouts and drifting on corners in the wet in his TR7...

BTW John, everything deteriorates [eventually], even in a vacuum/the dark and at whatever temperature you want. Whilst garaging may help extend the life of a tyre, in reality your garage isn't sealed and therefore is near to the external temperature/humidity, which changes over the course of the year significantly, which will, over time, cause deterioration of the tyre. Similarly not using your car much and keeping it in on position for a long time will induce flat spots which are definitely not good for the tyres.

when should you change tyres? - John F

BTW John, everything deteriorates [eventually]......

...in the real world; I quite agree, EA. But as for flat spots, my TR7 is used all year and rarely goes longer than 2/52 without a drive -e.g. last Wednesday was a rare fine dry day for a bit.

BTW, easyJet-type airbuses only have two more tyres than a car, but amazingly high pressures (>200psi). They really do go bang if they blow! Just shows how little stress a car tyre is under in comparison.

when should you change tyres? - Andrew-T

UV degradation takes place all the time, except when tyres are stored in the dark - and oxidation takes place constantly unless hermetically sealed - and who does that?

Not strictly true, RT. Oxidation is a free-radical process, accelerated by UV (and heat), which is the main reason why keeping tyres out of direct sunlight is the most effective way to retard surface cracking. So it doesn't take place 'constantly'.

when should you change tyres? - dimdip

I thought it was usual practice to re-tread aircraft tyres a number of times, is this still the case?

Shelf-life is one thing. What is the working life of an aircraft tyre - even after retreading, which I guess must happen quite often, seeing how much burns off at every landing ?

Yes retreading is the norm, up to perhaps five times as I understand it, though the release 'Form 1' will just state NEW or MANUFACTURED. I've worked in airline functions that use the technical and maintenance data, though never needed to work out the average on-aircraft life, but it is a matter of months (obviously depending on a lot of factors, not least the average number of sectors flown per day), so several hundred landings. The unbraked nosewheel tyres should last longer on average.

But in any case, airlines are tight, so they wouldn't set an arbitrary shelf-life without reason. Perhaps the transport aircraft use a softer compound than cars, but the point (as better explained by FP) is that degradation is apparently expected within that timescale -- even with tyres stored in a dark, dry stores.

[Edit - hadn't seen RT's post when writing that]

Edited by dimdip on 03/01/2016 at 13:02

when should you change tyres? - FP

"Clearly there are people on here with plenty of money."

Or, "Clearly there are people on here who don't cut corners for the sake of a few quid."

when should you change tyres? - John Boy

"Clearly there are people on here with plenty of money."

Or, "Clearly there are people on here who don't cut corners for the sake of a few quid."

They're lucky that they can take that attitude, but they can sound rather pious to those who don't have enough money.

when should you change tyres? - RT

"Clearly there are people on here with plenty of money."

Or, "Clearly there are people on here who don't cut corners for the sake of a few quid."

They're lucky that they can take that attitude, but they can sound rather pious to those who don't have enough money.

There are many ways to save money running a car - best not done on safety-critical items like tyres.

when should you change tyres? - Andrew-T

I have driven a car on 20-year-old tyres (with plenty of meat left) with no problems, and without troubling the MoT examiners. It all depends on how much time the tyre has spent in daylight (UV and oxygen slowly attack rubber) and on whether it has been kept properly inflated. If you can't answer these questions, change it for peace of mind - or get an MoT tester for his opinion.

when should you change tyres? - skidpan

I have one tyre that has a DOT code from 2010 and slight cracking in the tread. Is it still ok to use.........? Tread still has 5mm.

Yes, unless it has been internally damaged by a pothole. Five years is no age at all for a decent modern tyre. Slight superficial cracking is of no significance.

The only way to ascertain if a tyre has internal damage is to remove it from the rim. IMHO if any tyre fitter was prepared to re-fit a tyre showing cracking he should be sacked and possibly prosecuted for endangering life.

The cracking may be superficial but it is a hint that the tyre is suffering from degredation.

A few years ago I had a set of Michelins on my car that were about 3 years old and down to 5mm. The sidewalls were showing signs of surface cracking so I contacted them. They asked me to return them via ATS which was not a problem since I have another set of wheels. Once deflated and off the rims the cracks looked much worse. Within a few days I received a cheque for the value of the remaining tread, bet they would have done that if they had been OK to keep using.

Tyres cost peanuts compared to other motoring costs. If you use my Caterham as an example over 5 years and 10,000 miles I spend about £600 on insurance, £750 on VED, probably £500 on servicing and MOT's and about £1500 on petrol, grand total £3350. On top of that there will be other occational expenses, parts do wear out. I replace tyres when they have been on the car 5 years at which point they will be less than 1/2 worn. They are due early 2017 and a set of good quality 184/60 x 14 work out at about £250 all in. That is about 7.5% of my other motoring expenses so why would I want to risk my safety for such a small additional cost.

If you are not prepared to take motoring seriously you should consider returning your licence. Its not a challange to find out who has the oldest tyres or who extends their oil changes the longest. Its a serious matter as a blow out can kill.

when should you change tyres? - Engineer Andy

Indeed - Especially as we aren't the only ones whose lives we may be potentially endangering just for the sake of a few quid saving per year on tyres.