Bad set of tyres-BS?-

[marcush.]

I occasionally hear drivers bitchin about a bad set of tyres ,and we see this in F1 as well .

To my mind this is something of a mystery to me as :

A set of tyres will alwyas consist of 4 individual tyres.So in a race weekend ,especially when you got a spec tyre series it would be really hitting the jackpot to get 4 tyres at the lower range of tolerance in whatever performance generating
variable.
It may be possible you get 1 or 2 tyres from an older batch ,but still I feel if at all you might have one tyre below par in one particular set ,wich would of course throw out the balance .But then I demand of my driver to be able to point out wich one it was ,or alternatively the dta log should tell very much what happened.

I´m pretty sure the problem lies in personal error (wrong pressures )and the team not wanting to take the blame.I happened to work in a race team with 3 identical tyre pressure gauges -which where reading completely different pressures the range was no less than 0.3bar!!! so you were really lucky if you had a correct understanding what happened before ,during and after the runs pressurewise.....

[mep]

Yea true.
It sounds more like the tire itself is ok, someone just didn't handled it right.
Aren't the tires for one week end all from the same charge?
So even when there are some tolerances, they are for everybody the same.

I happened to work in a race team with 3 identical tyre pressure gauges -which where reading completely different pressures the range was no less than 0.3bar!!!

What kind of team was it?
Did you try to use only one of the gauges all the time?
So you might not know the exact value, but you are doing the same mistake every time so you will get used to it and find the optimal point quite fast.

[Jersey Tom]

The team can, to some degree, match sets of tires (stagger / sizing, durometer, etc).

There will however also be some stuff the team won't be able to measure, like springrate, that can definitely screw with your handling.

It's also possible a tire with some manufacturing error made it past QC at the factory.

But yea. It's luck of the draw either way.

[The Thorn]

You must keep in mind, especially in F1, that some things aren't told to us in the way it really is. Mostly you will hear a story around the problem, instead of something right to the point.

I do think that there are bad tyres used in racing. But a high-class as F1 should have done something about this a long time ago. As you say, it must be something to do with human error.
A tyre with a bit too much or less pressure can really upset the car under any situation. It will have effect on a lot of different factors that make a car drive like it is. Anything that makes the car stand a little bit different will do a lot to the overall feeling.

[Jersey Tom]

I do think that there are bad tyres used in racing. But a high-class as F1 should have done something about this a long time ago. As you say, it must be something to do with human error.

Uhh.. welcome to manufacturing. Things have variation.

[stl0]

The chemistry of the tires is certainly "high tech", but the manufacturing method is much less so. F1 tires are basically hand crafted, which inevitably leads to error. With the low quantities and short turn-around times I've always thought it's pretty incredible that the tires are as consistent as they are.

[marcush.]

what is considered high tech manufacturing ,is it really a fact that an automated manufacturing process would guarantee constant tyres?
I feel there is good reason for the tyre manufacturers to still have considerable handcraft in race tyre productionand this is not really the reason why they should not be able to build a constant product within one batch.
As far as I know in Series production every tyre is checked for balance (seen the yellow and blue dots on the sidewall?)and tyres wich are not up to spec then are 2nd choice or crap.With radials you don´t get much in terms of stagger .
I firmly believe in checking things personally (or at least within your entity/team),
Things you don´t check (diameter,shore hardness ,springrate ,runout etc..) will catch you some day ...Of course you have to take decisions where to spend your recources.

[Belatti]

I do think that there are bad tyres used in racing. But a high-class as F1 should have done something about this a long time ago. As you say, it must be something to do with human error.

Uhh.. welcome to manufacturing. Things have variation.

I would expect a F1 tyre to have a really small variability in its specs, more if taking into account that it has a huge effect in performance. If thats not the case... well... shame on Bridgestone AND its clients.

About the drivers bitching about "bad" sets, it can be BS sometimes, but also I guess that a performance ruiner can be the heat cycles inputed to the tyre. That is a variability you cant control (eg: fighting for a position while leaving the pits in a 2nd stint)

[timbo]

I think that since the tyres are not fully vulcanized they must be pretty sensitive to storage conditions.

[xpensive]

This "bad-set" talk has struck me too at times, as marcush points out, what are the chances of getting four rotten tyres in the same set? Moreover, say that you get better tyres on the left side of the car than on the right, how would that affect handling, faster when you turn right? Twitching badly when breaking?

[Jersey Tom]

This "bad-set" talk has struck me too at times, as marcush points out, what are the chances of getting four rotten tyres in the same set? Moreover, say that you get better tyres on the left side of the car than on the right, how would that affect handling, faster when you turn right? Twitching badly when breaking?

It's not that the tires are necessarily BAD, it's just as likely that they're just DIFFERENT.

For example, let's simplify the scenario and say you use the same tire on all 4 corners of the car.

You might have a set of tires, the springrates of which are 810 lb/in, 830 lb/in, 1040 lb/in, 1030 lb/in.

If you put them on the car as
RF: 810
RR: 1040
LR: 1030
LF: 830

You'd have a manageable, predictable car.

If you take the SAME set and put them on
RF: 810
RR: 1040
LR: 830
LF: 1030

You'd have some issues!

However, for the teams, while they can match sets of tire based on stagger and durometer.. they can't test springrate while at the track.

Or hey who knows. Maybe the team's tire guy wasn't doin his job right.

[Belatti]

JT, so you say they cant measure the tyre springrate once they put the rubber on the rim?

And you say tyre springrates varies THAT much??? Or that they can mount a rear tyre in the place of a front one???

[Jersey Tom]

I'm not aware that Bridgestone or the teams have anything to measure tire rate at the track, regardless of being on a rim or not.

Not saying they vary that much either. I have no idea how good or how poor Bridgestone's manufacturing variation is.

My point is that there are parameters you aren't going to be able to catch when making up a set. Doesn't mean that one tire in there is "junk," just means that isn't the best matching of 4.

That's life.

[marcush.]

my suggestion is: the variation in one batch of tyre is no more significant than say other factors the teams are unable to predict (like aeroforces in relation to ambient /track temp -the famous cloud in the right moment-)and quantify.It is surely not a situation were all tyres are equal but hey Button likes the prime tyre ,Barrichello is faster on the options(brings me to the question -bridgestone has only 4 tyre options available for this season iirc,has anyone a list of where which tyre options were used and who was fast on which tyre ,maybe theres a pattern in there that a particular tyre simply does not suit a driver /car?)
A pressure set wrong will affect everything:grip ,balance,springrate,Aerodynamic(different place in the Aeromap),so I´m pretty sure this is what it is.
As for the measuring of springrate ,this is not too complicated is it? would do that cold and warm new ,scrubbed after each heat cycle or stint.Obviously you´d need a extra tyre guy to perform this...recources bound...but maybe you´d get a trend -springrate fresh vs scrubbed and degradation,influence of changing springrate on car balance mechanically and aerowise(Aeromap)....lots of valuable information in my view.

[Paul]

I find it most likely that what is called a bad set of tyres is actually a bad combination of fresh tyres/track conditions/car characteristics. Basically the driver ruins the new tyres on first few laps and then struggles all the way till the end of the stint. I think if some tyre is structurally 'bad' it is more likely to suddenly disintegrate without letting the driver know something is not right beforehand.