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Thu 22 Jun 2023 08:59

New tyres/bust tyres on the back - edlithgow

A unresolved dilemma was hinted at in the recent tyre replacement/repair thread, mercifully shut down before someone told us tyres were our only contact with the road,

Its long been the official advice, from many authoritative sources, that the “best tyres go on the back” lets assume that this refers to somewhere wet, so that “best” can reasonably be taken to mean newest, with most tread.

Although this seemed to be discounted by all other posters in the thread, I find this advice convincing, having “lost the back end” of a couple of FWD cars due, I THINK, to lift off engine braking in slippery conditions.

I THINK the official advice is also that a blowout on a rear tyre is MORE dangerous than one on the front, and here Im less convinced, partly because it seems counter intuitive, and partly because I was once a passenger in a Commer van (not the most stable looking vehicle) that bust a rear tyre on the A1and no one noticed until the remains caught fire. Quite difficult to put out.

This is awkward because better bust on the back (IF valid) conflicts with best tyres on the back (which is valid) complicating a decision.

Mods please note: I am NOT trying to bypass your lockdown and revive the Recieved Opinion fest on new v used or repaired, etc, where Im happy in my heresy. Im raising a specific point im unsure of.

Opinion is of some interest
Experience is of more interest
Reference to authoritative sources would be the Gold Standard

I put it in discussion because thats where it started, though in fact its quite technical

Edited by edlithgow on 22/06/2023 at 09:06

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Thu 22 Jun 2023 09:54

New tyres/bust tyres on the back - Xileno

Not sure about the blowout issue, others will have more of an idea on that. But the debate about best tyres to the front or rear has always been quite lively. Here is one from over 20 years ago: www.honestjohn.co.uk/forum/post/index.htm?t=9451

Reminds me of the Waxoyl v Dinitrol debate on the LR forums. About the only area of agreement is that people have different views!

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Thu 22 Jun 2023 10:53

New tyres/bust tyres on the back - Terry W

Best front or rear is only important at the limits of grip - otherwise it makes no difference.

Limit of grip may be due to speed or road surface (wet, slick etc)

The front tyres experience more lateral force than the rear as they need to cope with steering inputs, not just the centrifugal force generated by the vehicles lateral acceleration.

Conventionally FWD are set up to understeer which is counteracted by greater steering inputs - a more natural reaction for inexperienced or incompetent drivers. Best tyres on the front limits this scenario.

Loss of grip on rear wheels requires opposite lock to correct, or the back may overtake the front of the car.

Research by RoSPA in 2005 (there may be more recent) showed limited loss of braking efficiency until tread was reduced to ~3mm, after which it fell sharply. Minimum is 1.6mm.

Conclusion - it makes little difference to grip unless the tyre is already well worn.

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Thu 22 Jun 2023 11:24

New tyres/bust tyres on the back - gordonbennet

It's so rare i buy tyres in double let alone single figures that the choice doesn't apply to me, however

My views haven't changed over the years, i'll always fit new (assuming not ditchfinders) tyres to the drive axle, i'd never want mixed tyre depths on a 4WD anyway so where to put new on those isn't in question.

I know the official line is new to the rear but as with everying else these days one size has to fit all and its always based on those who haven't a clue (which is one of the many reasons our industries, mine included, have gone around the U bend), this isn't some driving god self delusional thing, but, most of us who know our cars and know how to handle them are best placed to make such decisions for ourselves.

In real life scenarios most FWD cars have a tendency to plough straight on as in understeering, i dunno about you lot but i'm a world happier trying to correct an oversteer than i am realising the front wheels are no longer doing anything which is very difficult to correct in time.

No one bats an eyelid when a car with staggered wheels needs a new pair of tyres, are they exempt from grip problems?

What i don't understand is why so many people choose cars with hugely wide tyres, requiring weight and some decent tread to shift large quantities of water, yet so many people will run their tyres down to minimum depth...the number of smaller luxury cars (not heavy enough?) such as lower/middle range RWD German marques often fitted with stupidly wide elastic bands i've seen ended up in heavy rains stuffed into the motorway armco over the years must run into the many many dozens if not hundreds, sometimes on a motorway run in heavy rain its not unusual to pass half a dozen such incidents on the other carriageway over a 50 mile section, its often the same types of cars coming to grief.

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Fri 23 Jun 2023 03:44

New tyres/bust tyres on the back - edlithgow

Best front or rear is only important at the limits of grip - otherwise it makes no difference.

Isn't that true of ANY tyre safety consideration (apart from blowout vulnerability)?.

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Thu 22 Jun 2023 11:01

New tyres/bust tyres on the back - Engineer Andy

In terms of my personal experiences, worn / old (hard) tyres on my current Mazda3 sent the back end stepping out twice within a few weeks of eachother on roundabouts on wet days. Luckily on both occasions, no harm came to pass, but it scared the cr@p out of me and convinced me to change tyres.

When I was researching the change, I did find out that the existing (OEM fit) tyres did not have a good reputation generally, and especially as they aged (whatever the wear) in the wet. In the dry, they were still good at handling, if rather noisy and not so comfotable.

The new tyres had a much better review rating, which was something I could attest to throughout they life. I would say that rotating tyres so that the fitted rears (on FWD cars anyway) get equal usage helps as well, because the wear exposes 'new' rubber which isn't as hard as the 'outer' surafce if left on that axel.

I only changed the second set because of the age (they were 6 years old, but at about 4-5mm tread ish if I recall) and because I was downsizing the alloy wheels from 16in to 15in, and thus had to change tyres anyway (one was leaking because the alooy was corroded, the others appeared to be going the same way). The tyres were otherwise fine.

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Thu 22 Jun 2023 13:31

New tyres/bust tyres on the back - Adampr

All I can say is that I have had a one blowout ever, and it was the rear wheel on a RWD car. I most certainly noticed it, but was able to pull over to the yard shoulder without any drama. That wasn't down to my exceptional driving skills, it was easy.

On a FWD car I've always been more concerned about the front tyres as they do everything

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Thu 22 Jun 2023 14:03

New tyres/bust tyres on the back - mcb100

I once watched a demo by the late Eric Carlsson (former rally driver) drive over a tyre knife, instantly deflating a front tyre at 60mph in a SAAB 900 with both hands up through the open sunroof.
The car continued straight as a die.

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Thu 22 Jun 2023 14:14

New tyres/bust tyres on the back - sammy1

I have never experienced any problem with lack of grip with tyres skidding or stepping out of line in normal conditions wet or dry on the many cars I have driven. On black ice I have experienced that lightness when the car has momentarily poor grip and snow well you can go anywhere even if you are careful. I always put new tyres on the driving wheels. Poor grip is responsible for a lot of accidents and I think there are a lot of drivers just relying on the MOT before spending money on tyres. Runflats are an excellent innovation but they have never caught on due to the extra expense of rim and tyre. I don't believe in the criticism of the so called ditch finder cheaper tyres. I would not put them on a performance car but for the majority of buyers they are perfectly satisfactory.

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Thu 22 Jun 2023 15:59

New tyres/bust tyres on the back - gordonbennet

I don't believe in the criticism of the so called ditch finder cheaper tyres. I would not put them on a performance car but for the majority of buyers they are perfectly satisfactory.

I tried two experiments to see if my prejudices about ditchfinders were still valid.

The current Prado came on a brand new set of Chinese tyres, the first year they seemed ok but became decidedly twitchy in the wet in year two, still had full tread, i replaced them and 4 or 5 years later the Yokohamas i fitted grip as well in the wet/snow/slush as they did new.

I deliberately bought a set of cheap tyres for our ageing Mercedes, again the first year they seemed ok and in their defence the quietist car tyre i've had, however after two unprovoked wet oversteer slides thankfully easily controlled they were removed and the Uniroyal Rainsports still fitted restored its previous rock solid grip.

Summary, i'm not having budget tyres again, but i don't pay top dollar for the likes of Michelin either, i have half a dozen makes incl Vredestein and Yokohama which i keep my eyes open for when needed and usually manage to snaffle a bargain before needed, looking on Goodyears favourably too because unlike some others the ones recently fitted to the family Golf came with a good 8mm of new tread.

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Thu 22 Jun 2023 19:04

New tyres/bust tyres on the back - Engineer Andy

I don't believe in the criticism of the so called ditch finder cheaper tyres. I would not put them on a performance car but for the majority of buyers they are perfectly satisfactory.

I tried two experiments to see if my prejudices about ditchfinders were still valid.

The current Prado came on a brand new set of Chinese tyres, the first year they seemed ok but became decidedly twitchy in the wet in year two, still had full tread, i replaced them and 4 or 5 years later the Yokohamas i fitted grip as well in the wet/snow/slush as they did new.

I deliberately bought a set of cheap tyres for our ageing Mercedes, again the first year they seemed ok and in their defence the quietist car tyre i've had, however after two unprovoked wet oversteer slides thankfully easily controlled they were removed and the Uniroyal Rainsports still fitted restored its previous rock solid grip.

Summary, i'm not having budget tyres again, but i don't pay top dollar for the likes of Michelin either, i have half a dozen makes incl Vredestein and Yokohama which i keep my eyes open for when needed and usually manage to snaffle a bargain before needed, looking on Goodyears favourably too because unlike some others the ones recently fitted to the family Golf came with a good 8mm of new tread.

To me, it's why real world reviews from us car owners on the likes of TyreReviews helps others make much more informed decisions about tyre purchases, and thus the more such reviews there are, the better.

I would strongly advocate all of us posting such reviews there (for example) to help, though I would advocate doing so after the set has got to at least a third worn or 2 years old, in order to give a more useful review.

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Thu 22 Jun 2023 17:19

New tyres/bust tyres on the back - John F

I think it's generally agreed that if a tyre unexpectedly deflates, the car will be more controllable if it's a rear tyre. As for the 'put the best tyres on the rear' advice, my practice is to try to replace all four at the same time. Assuming no damage requiring replacement, this means half the mileage will be done with the worst tyres on the rear. Guessing a 30K mile tyre life, I swapped Mrs F's Pug's tyres front to rear at 15,000 miles. There's not much more than one millimetre difference, and as more mileage is done, the difference will lessen until they should be equally worn when replacements are required.

Here endeth some more 'usual nonsense'.

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Fri 23 Jun 2023 02:01

New tyres/bust tyres on the back - edlithgow

I think it's generally agreed that if a tyre unexpectedly deflates, the car will be more controllable if it's a rear tyre.

That would have been my (and perhaps most peoples, confirmed by ChatGPT) intuitive guess, but that doesn't necessarily make it so.

A quick Internyet search came up with lots of references to "expert opinion" to the contrary,for example:-

www.cartalk.com/content/rear-tire-blowouts-v-front...s

or better

www.tirereview.com/so-where-do-new-tires-go/

"If the blowout is in the rear, there is nothing the driver can do; there is virtually no way to control the fishtailing rear end of the car."

I havn't (so far) found a direct authoritative source for comparative controlled blowout testing,

(The best-on-rear question has apparently been decided in the US courts, with big damages awarded against deviators, so I'd guess the evidence there is compelling)

Even Michelin agree, and they confirm that your tyres are your only contact with the road!

www.youtube.com/watch?v=tUW6KmvhyjU

Heres a rather uncontrolled rear blowout, which doesnt look to me like it would have been very easy to control.

www.youtube.com/watch?v=LWgVaqbu5zc

Maybe the driver braked, (which you aren't supposed to do) but it didn't really look like they had time to do anything.

It can be done though

www.roadandtrack.com/motorsports/videos/a30122/wat.../

but perhaps not by me

More American Excess, Front tyre blowout description about 5 mins in. Suggests cruise control might save you by automatically applying accelerator

www.youtube.com/watch?v=SC6myAyUNzM

Edited by edlithgow on 23/06/2023 at 07:48

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Thu 22 Jun 2023 17:51

New tyres/bust tyres on the back - mcb100

‘ Conventionally FWD are set up to understeer which is counteracted by greater steering inputs - a more natural reaction for inexperienced or incompetent drivers. Best tyres on the front limits this scenario.’

Unless the understeer has got to the point where the only remedy is to take the lock off, let the tyres grip, and try again. Far from intuitive. Fortunately, a modern stability control system will by then have applied the brakes on an inside rear wheel to help control the car before the driver has realised there’s been a problem.

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Thu 22 Jun 2023 19:14

New tyres/bust tyres on the back - badbusdriver

I don't believe in the criticism of the so called ditch finder cheaper tyres. I would not put them on a performance car but for the majority of buyers they are perfectly satisfactory.

There are two problems with this view. First is that it assumes only performance car drivers will ever find themselves in a situation where they need to make an emergency braking or avoidance manoeuvre, particularly on a wet road (because this is where the difference is going to be at its most obvious). Second is that it assumes non-performance cars are never driven at or near their limit and that performance cars are only ever driven at or near their limit.

But going back to what GB said about huge ultra low profile tyres, if you have a car with sensibly sized tyres, quality rubber is not that dear.

Personally, I'd sooner have a car with sensibly sized tyres that I could afford to put decent quality tyres on than something with huge tyres that I couldn't.

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Fri 23 Jun 2023 03:38

New tyres/bust tyres on the back - edlithgow

‘ Conventionally FWD are set up to understeer which is counteracted by greater steering inputs - a more natural reaction for inexperienced or incompetent drivers. Best tyres on the front limits this scenario.’ Unless the understeer has got to the point where the only remedy is to take the lock off, let the tyres grip, and try again. Far from intuitive. Fortunately, a modern stability control system will by then have applied the brakes on an inside rear wheel to help control the car before the driver has realised there’s been a problem.

Not on any car of mine.

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Fri 23 Jun 2023 12:53

New tyres/bust tyres on the back - Bolt

‘ Conventionally FWD are set up to understeer which is counteracted by greater steering inputs - a more natural reaction for inexperienced or incompetent drivers. Best tyres on the front limits this scenario.’ Unless the understeer has got to the point where the only remedy is to take the lock off, let the tyres grip, and try again. Far from intuitive. Fortunately, a modern stability control system will by then have applied the brakes on an inside rear wheel to help control the car before the driver has realised there’s been a problem.

Not on any car of mine.

By the time you've all thought about what your going to do the ABS and VSA have done it all for you, which is the reason its there.

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Fri 23 Jun 2023 13:33

New tyres/bust tyres on the back - Terry W

For moderately cautious and observant drivers it is possible to drive for years (maybe decades) without experiencing a skid or slide - occasional sharp straight line braking aside).

Unless track days are part of your leisure time fun, or you have recently been on a skid pan to hone your reactions, a car equipped with ABS, traction control and other gizmos will comfortably beat the driver to best car control.

The goal is to avoid hitting anything, not demonstrate prowess in car control. In most circumstances the best action is to steer where you want to go, brake lightly, let the electronics do their thing. If needed brake hard and let the ABS kick in.

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Fri 23 Jun 2023 14:32

New tyres/bust tyres on the back - edlithgow

If needed brake hard and let the ABS kick in.

Seems likely that, in the case of a blowout, that would get you dead, since braking is VERY well known to be the worst thing you can do, and braking with ABS is still braking.

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Sat 24 Jun 2023 07:51

New tyres/bust tyres on the back - Bolt

If needed brake hard and let the ABS kick in.

Seems likely that, in the case of a blowout, that would get you dead, since braking is VERY well known to be the worst thing you can do, and braking with ABS is still braking.

ABS is still braking but controlled by the ecu, ie brakes put on as and when needed to prevent tyre slip and skid, ( I have to say I`m not entirely convinced ABS is the best form of braking as in certain conditions ABS cannot control a car fully) where a skilled driver could possibly do a better job.... though in most cases it does.

I always put new tyres on where the old came off, I have never thought the idea of putting new on either rear or front to benefit tyre wear, and especially now that our roads are as bad as they are, tyres do take a hammering and suspect in some parts of the country possibly have better road surfaces than SE London so probably last a lot longer

I haven`t mentioned repaired tyres as due to over the last 10 years or so, none of my tyres have been repairable, so had to be replaced and I certainly wouldn`t allow a plug to be used, patch imo is ok and safe though all my punctures have been corner of tread to sidewall so non repairable, just my luck really but after seeing so many tyres blow because of bad repairs kind of put me off tyre repairs, I also years ago had a tyre blow during a road flood, lost the car and hit a lamp post, wrote the car off and was only doing 20 when started going through the flood which wasn`t seen it was raining too hard

I now don`t take any notice of what miles the tyres do I just replace as and when they get to around 3mm apart from checking pressure and tread depth weekly, I give up wondering how many miles I get from them as long as they do the job

like wiper blades, I don`t wait until I can hardly see through screen to replace, I do so every year except if they show signs of not clearing screen properly, I then replace even if they are only 6 months old.

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Fri 23 Jun 2023 14:24

New tyres/bust tyres on the back - edlithgow

‘ Conventionally FWD are set up to understeer which is counteracted by greater steering inputs - a more natural reaction for inexperienced or incompetent drivers. B"st tyres on the front limits this scenario.’ Unless the understeer has got to the point where the only remedy is to take the lock off, let the tyres grip, and try again. Far from intuitive. Fortunately, a modern stability control system will by then have applied the brakes on an inside rear wheel to help control the car before the driver has realised there’s been a problem.

Not on any car of mine.

By the time you've all thought about what your going to do the ABS and VSA have done it all for you, which is the reason its there.

As I said, (see above) it hasn't been there on any car of mine, and I don't expect it will be.

But if it was, it wouldn't decide where I put my best or patched tyres, which is, like, the topic.(see above again)

I dunno if or how well these systems deal with tyre problems, but, to quote Mr Miyagi "Best defence. No be there"

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