Wheely good question

[DavidRutherford]

I also dont quite accept that worn tyres have more grip, reason being that as the tread is less, the blocks overheat as there is less rubber & therefore offer less grip.

I'm sorry, what utter pseudo-science bollocks is that? I'd like to hear you try explaining that to anyone who actually understands tyres. Slick tyres (IE with NO tread at all) offer better grip than those with treads. This is why they are used in motorsport. The ONLY reason we have treaded tyres is to disperse water, and you might have noticed that an F1 car (or indeed any other motorsport car) goes faster on slicks than it does on treaded tyres. An amount of treading was brought back into F1 tyres in order to slow the cars down. The extreme opposite of this is with farm vehicle tyres, which are often affectionatly known as "straight-on's", because the tread is so open and wide that they offer no cornering ability at all, and hence you go Straight on, regardless of steering input!

Reason why i believe this, is that every tyre i've had on front wheel drive cars, the front as it wears (in the dry) they start squeeling a lot more & at lower speeds,

Noise generated from the tyre indicates that you no longer have large blocks and hence there is less "give" in the surface of the tyre to take up the fact that the outer of the tyre is following a longer path than the inner. That "squeal" indicates that you have more grip. Most noticeable in car parks, where there is a layer of rubber on the surface from lots of cornering cars.

it's not an exact science imho

I suspect most tyre manufacturers would disagree with you on that, and I also suspect they may know more about it....

[Dollywobbler]

If we could keep things civil...

Interestingly, Audi recommended putting new tyres on the rear - I think one reason to do this is that rear tyres don't get much wear, so are likely to become dangerous from ageing rather than wearing out. I personally prefer grip at the front and avoid oversteer by not driving like a pillock - ie don't lift-off mid-bend. Never had an issue.

[BX Bandit]

My XM has something of a motley collection of tyres, the front having a Nexan and a Dunlop in part-worn state, and a mismatched cheeky pair of chinese offerings on the rear......

that's one of the funniest things I've read in ages


I'll add two things....

.... the blocks overheat as there is less rubber & therefore offer less grip.....

How fast do you drive and what power are you putting down to melt the rubber on your tyres!?

You see F1 drivers weaving when the pace car (or whatever it's called - the one that comes out when there's an accident) to keep the rubber warm on their tyres to provide more grip. i.e. hot tyres=more grip.

I think Mulley is referring to though and may be getting his wires crossed is that when cornering in very wet conditions where aquaplaning is likely, the safest option is to have the deeper treaded tyre to minimise the likelihood of said aquaplaning at the rear resulting in loss of traction and thus the rear of the car swinging outwards. That however, is not oversteer!

[Matt H]

In the great words of Dr. Neil Fox:

That's scientific fact... There's no actual proof for it, but it is scientific fact

I think the recommended life of a tyre is six years... after that the rubber starts to deteriorate, and stopping distances will increase, however a pair of six year old Continentals will still be better in every respect to a pair of brand new 'West lakes'. Although, this info comes directly from tyre manufacturers, and they are not entirely impartial are they... So make of what you wish.

My 14 TGE had a set of 165 Michelins on it when I bought it, and when I switched to 195/60s (even on budget tyres) the difference was astounding...

[MULLEY]

Who would have thought that my reply would have cause such a stir

Believe what you want to believe & even disagree with me, i'm just giving my personal opinion. Just because you've been doing something for 20 years kiwi, doesnt mean you been doing it right

The bit about motorsport is irrelevant tbh, as the construction of race tyres bears no resemblence to road tyres or the conditions they face so that example is useless.

TBH, you'd have to be a bit of a tit to bin a car off the road as i dont get how you can lose it, unless there were other mitigating circumstances rather than running out of talent.

Never had an accident just for the record, perhaps because of my tyre practices to date I bet i come a cropper tonight for having said that

Have to disagree with the noise as well David, new tyres no noise when cornering at certain speed, as tyre wears down tyres make more & more noise going at same speed Sounds like grip is reduced to me as steering feel becomes less precise as well.

Oh well, it'd be boring if all of us agreed on something.

[Dollywobbler]

I've not had tyres get noiser as they aged - but different types do make more noise than others - a 2CV on Uniroyals is particularly squealy! (though oddly they were quite grippy at the same time...)

[Vanny]

Audi recommended putting new tyres on the rear -

Not so much Audi, but tyre manufacturers. It's more about user error than wear or performance, poor drivers cope better with the change to good tyres on the rear than on the front, given that most cars understeer,

Michelin knows best!

[DavidRutherford]

The bit about motorsport is irrelevant tbh, as the construction of race tyres bears no resemblence to road tyres or the conditions they face so that example is useless.

Given that it's still rubber in contact with a road surface I don't see how that statement can possibly be true. Michelin, Goodyear and the like make a very specific point about their motorsport experience paying dividends when it comes to development of car tyres.

Have to disagree with the noise as well David, new tyres no noise when cornering at certain speed, as tyre wears down tyres make more & more noise going at same speed

I've already explained why that happens... did you read it?

The reason manufacturers recommend putting new tyres to the rear is only because then you have better water clearing ability on the rear axle, and hence are less likely to aquaplane the back of the car. Nothing to do with dry weather performance at all.

[BX Bandit]

You can lead the horse to the water.....

[MULLEY]

Here is a some spiel from someone else who had front tyres that were low on tread, yet brand new tyres outperformed his old one's. Yet according to some of you this is impossible:

When I saw the article in the Southern Daily Echo that Dunlop were asking for people to test their new tyres, I didn't think I would have any chance of getting four new tyres for free. So it came as a bit of a shock when I received the e-mail telling me I was one of four people chosen to have a set of the new Sport Maxx TT tyre fitted to my car.

First of all I should tell you about my car. It is a Renaultsport Megane 225 F1 Team and it is a superb piece of machinery. It has a two litre turbocharged engine developing 225bhp which means it is very quick and it just keeps on pulling. The chassis has been tuned to give a focus on track driving but is very usable in everyday situations. The original tyres were Dunlop Sport Maxx and I certainly thought they were a very good tyre. I had used them on two track days last year and they performed very well.

Being chosen as a tester couldn't have come at a better time for me as my front tyres were very worn and had just about reached the tread depth indicators. Getting the new ones fitted was very easy, I just popped over to the HiQ Centre in Northam, Southampton, and an hour later I had four shiny new Sport Maxx TT tyres on my 18" rims. It was clear from the start that these were a very different tyre from the ones I had been using before even if they did share the same name.

The most obvious difference was the tread pattern - the new TT tyre has an asymmetric design whereas the original ones were a directional design.Using this design Dunlop has managed to increase grip levels on both wet and dry surfaces. Not as obvious but just as essential in giving increased tyre performance is the other technology Dunlop has used in developing the tyre; the main difference being the introduction of Kevlar into the sidewall compound making it much stiffer and enhancing road feedback.

My initial reaction to using them was that they were superior to the tyres that had come off. I was able to better feel what the tyres were doing as they went round corners and therefore travel that bit safer and quicker. On motorway driving it became obvious, and it did not matter what the road surface was, that the tyres produced hardly any noise at all. On some surfaces I used to get a lot of tyre roar but this was almost completely eliminated with these tyres.


David, i did read your explanation about tyre noise, i just disagree with your explanation as the noise is telling you that its losing grip as its starting to slide, hence the noise, if there was more grip it would be silent as there is no sliding. I do agree that its best to put new tyres on the rear for aquaplaning, but again you have to be going at some rate of knots to start aquaplaning in the 1st place. Did you see Vanny's link for Michelin's take on said debate?, but at the limit in the dry its also of benefit, albeit less of an effect than in the wet.

The bit about motorsport is of course MARKETING, who wouldnt want to say that some of the technology in their race tyres is also in your road tyres, whether thats actually true or not i've no idea, some elements possibly, but since the only common ground between them is that they are tyres & everything else is fundamentally different, i therefore stand by my comments that using that as an example wasnt really ideal. Road tyres are supposed to last for years & thousands of miles, the complete opposite of motorsport tyres who even have specific slick compounds for different track conditions & then even have different wet tyres as well depending upon how much standing water their is. Road tyres have to try & do all of this just on one compound, one tread pattern etc....

Changing the topic slightly:

Interestingly, i read an article sometime this year where they tested some tyres, i think they may have been continentals, they used a standard ford focus 1.6, & used the following tyres:

1) Brand new tyres

2) Part worn tyres of the above

3) Old new tyres (i think these were approx 5-6yrs old & were unused)

4) Old new tyres, scrubbed down to replicate part worns.

Needless to say, they were used in the dry & wet, emergency braking & cornering & manoverabliity tests, & in order of performance they were:

1
2
3
4

The difference between 2 & 3 was reasonable to make you think twice about purchasing unused but old tyres, but 4 was basically a disaster, pretty poor in the dry & lethal in the wet.

So when i said its not an exact science, then i also stand by that, as so many cars are running around with non matching axle sets of tyres along with different sizes as well, with different tread patterns & therfore different compounds, wear rates etc...

[MULLEY]

Found this article about what makes a modern tyre these day's, its of course just one brand of a particular model, but just goes to show the complexity involved:

http://www.tyrereviews.co.uk/Article/ho ... ructed.htm

Point 5 is interesting in that it seems to imply "to maintain constant grip performance" thats why this tyre has these elements to it, rather than saying "as it wears it improves its performance", or have i misread it?

[docchevron]

First of all I should tell you about my car. It is a Renaultsport Megane 225 F1 Team and it is a superb piece of machinery.

Erm, see this says it all right? You clearly cannot believe a word this dude is saying, he thinks a Toilet is a superb piece of machinary, whereas we all know that Renaults are shit, and anything bolted to or in any way connected with said Renault will also be shit, therefore his tyres are shit, and his ability to judge his tyres is also shit.
Equally the dude states that the name of thetyre may be the same, but the whole construction of the tyre is different, so it's not like for like is it?
And again, they were fitted to a Renault, therefore, shit.

David, i did read your explanation about tyre noise, i just disagree with your explanation as the noise is telling you that its losing grip as its starting to slide, hence the noise, if there was more grip it would be silent as there is no sliding.

Erm, thats not the case, nor what David said...

but again you have to be going at some rate of knots to start aquaplaning in the 1st place.

Ooh, dunno about that so much, I've had some fairly hairy moments even at low speed on fairly new Michelins. Dont use Michy's anymore..

The bit about motorsport is of course MARKETING, who wouldnt want to say that some of the technology in their race tyres is also in your road tyres, whether thats actually true or not i've no idea,

Ok, to be a pedant for mo, you've rather contradicted yourself there a touch.. It's actually not just marketing, the amount of technical stuff that goes in to designing tyres these days is quite a bit more than it used to be, and motorsprt gave the biggest advances in road tyre technology.

Yes, race tyres are designed for a job, as are road tyres, those two jobs are fundamentally different,although forever intertwined.
I mean, you wouldn't imediatley link a frying pan and a space shuttle, but the technology from one made the other non stick. Which isn't really what you want in a tyre......

[kiwi]

Shall I mention Notrogen

Naa better not

Ok lets skip to the basics!

1, Worn tyres offer less grip? well not always they just last less time BUT

2, Depends on the Tyre make, compound etc etc some tyres wear better than other and some offer more grip. Introducing Snow tyres the ideal traction control tyre when the snow starts to fall to a point out performing a similer tyre in the same conditions maybe?

3, Tyre rotation! Several recommendations for that but are we talking in general or are we just talking about the Original posters Citroen BX?

4, The recommendation that have always been told right or wrong is Front to Rear thats putting new to the front. Of course you could just rotate them every 6,000 miles so you get an even wear and replace the lot all in one

Now lets go back to personal experiance

The worse Tyres I can recal recently have been a set of Godyear Ducaros which came highly recommended, except the BX hated them chewed them up in 10,000kms and I found them rather less grippy in the wet and forced me on to snow chains quicker than other people.

Thing is by the time need some new tyres you can bet you last dollar, pound or Euro that you wont be able to get that great make you like again.

Now we go back to the chinese makes of Tyre, well I would stay clear of them for 2 reasons one I dont trust cheap tyres from a cheap country and two its the principle of the thing. Especially now that Tyre makers are closing and we are getting forced onto these cheap chinese makes.

[DavidRutherford]

Here is a some spiel from someone else who had front tyres that were low on tread, yet brand new tyres outperformed his old one's. Yet according to some of you this is impossible:

Not in the slightest. What I said was that as a tyre wears, it's performance improves. If you were to fit a brand new tyre of EXACTLY THE SAME TYPE, then there would be a small drop in handling. Of course if you fit a pair of chinese pre-greased tyres then the drop off will be massive, conversely, by fitting a pair of much better quality tyres there will be an improvement in handling.

Adamski mentioned this recently actually.. he had to fit a pair of super-cheap budget shitty tyres to the front his CX for MOT, and it handled like a wayward shopping trolley thereafter. So badly in fact that he took them back off and fitted the old pair of (fairly knackered if truth be told) Michelins for safety. Shortly thereafter he then fitted a complete vehicle set of new michelins, but the point is that a brand new tyre with lots of tread DOES NOT necessarily perform better than an old worn one, not least because tread depth has nothing to do with grip. All tread depth does is make the tyre able to clear water, and make it (slightly) less stable.

[Vanny]

I tells you what i think we better let the FIA know about this conversation. I mean if they are forcing teams to use NEW tyres to slow them down, but infact scrubbed tyres are slower then the blue book must be wrong