New tyre legislation...

[Chr1sch]

I understand from another forum that new legislation is coming in that will limit the ability to run track tyres on the road, has anyone come across this?

Context:

Post #10
Right just spoke to Mr Tyre who know there stuff & supply lots of the Teams etc .

After Nov 2014 any tyre made not just Track tyres have to conform to lots of testing ..wet grip ..dry grip ...noise ...etc !
Where all the track tyres are coming undone is Noise ...
All the top end tyres are only meeting F grade & they need to be G to pass .!

Everybody has stocked up on old tyres made before 2014 as that's ok ...
But the EU has given Track tyres until end of 2016 to get rid of old stock ..

Now here's some info ..
No tyre including new Toyo R888R that's the first top end tyre to meet the Regs are anywhere near as good as the old tyres YET ????
Dunlop & others are working on tyres & trying to give DZ03g quality but because of Noise it's going to be difficult so say ?

[McSam]

Whoever wrote that doesn't fully understand the regulations. Noise level is not banded by letters, the actual decibel result is published and then put into one of three bands - above future limit, below future limit by up to 3dBA, below future limit by over 3dBA. Only rolling resistance and wet grip have lettered bands.

The regulations have been in force since 2012. Since then, anything over the current limit has of course not been permitted for sale in the EU, or at least could not be E-marked for road use. If the noise limits are changing to the next step (or perhaps did change in 2014, though two years seems unreasonably short given the average lifespan of a tyre design so I doubt that), then any tyre that is in that loudest category (three black waves shown on the label) will need its design changing, re-testing or withdrawing.

I wouldn't panic just yet, not least because a smaller tread depth generally quietens a tyre, giving most track tyres a slight advantage in the tests to make up for their noisier patterns and compounds.

Edited by McSam on Friday 31st July 08:58

[Chr1sch]

Very useful thanks mate

[McSam]

No worries. To be honest, while the stiffer sidewall typical of track tyres doesn't help road noise, the worst of it is usually due to cavity resonances caused by the tread pattern. In a road tyre you design to avoid this sort of effect because it's very annoying to occupants, but for track-focused tyres it's seen as an acceptable compromise so less of the development budget is spent on it. If the noise regulations tighten to the point where track tyres start failing, small changes to the tread design would likely be enough to get them through.

I always expected rolling resistance (billed as fuel efficiency in the EU labels) would be the real issue, due to the softer compounds used on track tyres, but they don't seem too bad. Rolling resistance has two main basic components, the friction drag from the rubber compound and the hysteresis loss from the contact patch deforming as the tyre rotates - my theory is that the stiffness of track tyres means less hysteresis loss, making up for the worse friction drag from the soft rubber.

[AdiT]

As I understand it some existing tyre designs were exempt from having to meet the labeling regulations when that was introduced and that exemption has now expired. The result being that Toyo have withdrawn the r888 and although Yoko are continuing to produce the 048, it will no longer be E marked and have "not for road use" on it. Of course there's still old stock around (though some sizes are already getting harder to find) and it is legal to use.

Toyo claim the new r888r is as good if not better than the old tyre for both dry/wet grip and last longer.

[Broomer]

Chr1sch said:

All the top end tyres are only meeting F grade & they need to be G to pass .!

Isn't an 'A' rated tyre the quietest with 'G' being the nosiest rating that there is?

If so F rated is fine as it's quieter than the G rating that's required.

[McSam]

AdiT said:

As I understand it some existing tyre designs were exempt from having to meet the labeling regulations when that was introduced and that exemption has now expired.

Ah, that's interesting and could explain why it's suddenly becoming a concern in some cases. Typically new legalisation would only apply to new products, but since you could feasibly keep producing the same tyre design for ten years or more if it suited you, I guess there would need to be a time limit.

Broomer said:

Chr1sch said:

All the top end tyres are only meeting F grade & they need to be G to pass .!

Isn't an 'A' rated tyre the quietest with 'G' being the nosiest rating that there is?

If so F rated is fine as it's quieter than the G rating that's required.

It would be, but as above tyres are not banded for noise at all, only for rolling resistance and wet grip.

[Broomer]

Ah yes I see that now, the article was wrong. Two black lines out of three for the DB's is fine and that's what the Federals I use have got so they shouldn't be affected.