tyre rating dilemma

Ultrasonic

Hintza wrote: »

The tyre companies could make all tyres AA rated but buyers wouldn't be too keen when they need to be replaced after 5,000 miles.

There are more to tyres than the official rating.

Good point. The lack of a wear rating on the label seriously undermines the usefulness of the rolling resistance rating for both financial and environmental considerations.

2nd_Time_Lucky

Thanks to all who took time to reply :T

I know it's a heavy old car but we've been together a long time and its still smart, reliable and its worth very little if sold so it seems MS to keep going, for my short daily journey I doubt I'd reap the benefit of spending £££ to change. I think I'll stick with the Yokohama as it keeps a matched set and they seem hard wearing , good on and off road grip too

AdrianC

Joe_Horner wrote: »

Further to my earlier post, just had a pair of fronts put on my workhorse this afternoon.

Being a tight git and a driving God, I went for the cheapest available, which happened to be Landsail

Now why do I suspect they're going to be proven to be extremely well named?

The moral of that little rambling? Either the ratings are completely screwed or (a) Premiums are not always more capable than budgets, at least within what's scored

I know where my money's being put on that one...

Joe_Horner

AdrianC wrote: »

Now why do I suspect they're going to be proven to be extremely well named?

Well, on the way to work this morning I decided to push a bit down our local damp, mud covered, roads (including A, B and dual carriageway). Despite peoples' heartfelt concern for me (much appreciated btw) I didn't slide off into oblivion. Ok, I wasn't pushing to the absolute limit ut I never do that on the public road anyway, so they behaved perfectly well for the "spirited" end of my normal driving style.

I also intentionally put the n/s one through some nice standing water on a straight bit at around 50mph and completely failed to aquaplane it, so that's another tick.

Encouraged by that I tried a test-failing "emergency" stop from about 30mph - foot hard on the brakes with no subtlety, no progression and no ABS.

This time I nearly died.

The new fronts gripped just fine, but the part-worn (about 4 - 5mm tread) Michelin Energysavers on the back let go rather suddenly, despite having a good load in the back and correctly set brake bias.

So, however bad they may be compared to "quality" new tyres, they seem to be better, at least on my car, on greasy roads than mid-life premiums.

I may update when I've got a few more miles on them

Ultrasonic

Joe_Horner wrote: »

The new fronts gripped just fine, but the part-worn (about 4 - 5mm tread) Michelin Energysavers on the back let go rather suddenly, despite having a good load in the back and correctly set brake bias.

So, however bad they may be compared to "quality" new tyres, they seem to be better, at least on my car, on greasy roads than mid-life premiums.

Braking hard will of course transfer weight forward making the rear tyres much more likely to lose grip than the fronts.

That said, plenty of 'good' new tyres handly badly when brand new, so you seem to be doing OK .

(You 'should' have your new tyres on the rear though )

Joe_Horner

Ultrasonic wrote: »

Braking hard will of course transfer weight forward making the rear tyres much more likely to lose grip than the fronts.

Yes, weight will transfer but that's what the load sensing valve (which is working and correctly adjusted) is there to account for. The system should reduce pressure to the rear brakes so that the fronts lock first because that's far safer for the average driver.

I suspect that part of the difference is that, at around 3 years old (since fitting, haven't checked their date codes), the Michelins will have started to harden up.

Which is another potential variable to throw into the debate - new (but run-in) budgets or old, hardening, premiums?

eta: new on the front are fine as long as you don't (accidentally) push the limit. If you push it intentionally it just keeps things interesting

Ultrasonic

Joe_Horner wrote: »

Yes, weight will transfer but that's what the load sensing valve (which is working and correctly adjusted) is there to account for. The system should reduce pressure to the rear brakes so that the fronts lock first because that's far safer for the average driver.

I was talking about the tyres losing grip as a result of less downward force on them, which I think is a totally separate issue to what the brakes are doing.

Joe_Horner

As long as you're braking in a straight line (which I was very careful to be doing!) there's nothing but the braking force to make the rears lock, and the braking system should be set up to ensure the fronts lock first even allowing for the weight transfer because a front wheel skid will be a straight line, which is easier to recover and usually safer for other road users (you don't go spinning randomly into their path)

Heavy braking in a corner is another matter and can easily get the back end letting violently. I won't be testing that one

Ultrasonic

I had taken from your description of the back end 'letting go suddenly' that the back end stepped out? I was therefore thinking of the rear tyres losing lateral grip, not the brakes locking.

Joe_Horner

It did start to because there's no such thing as a really "straight line" on the road and, as soon as the brakes start a skid, it takes very little to nudge the back end out of line. Any of the assorted lumps and bumps on our 3rd-world A roads will do it!

At which point you have the back end wanting to continue at speed while the front's slowing down rapidly..