Tyre speed limits - what's the tolerance?

[Somewhatfoolish]

I just drove from Frankfurt to Nuremburg and annoyingly windscreen said stay at 210km/h. While I did this and interestingly didn't get overtaken once, when I drive back in a few days time I'd much rather do 250km/h (and it's a 340i so perfectly capable of it), cause I feel it's a moral obligation to use a car properly and set a good example to my daughter.

If the speed codes on the tyres, which I didn't check, turn out to acutally be for 250 (and I don't see why they can't be; my winter tyres in the UK generally are) then I'll just do that. If they however are actually set to 210 then what speed can I actually safely do - I assume there's some sort of margin?

[brillomaster]

Unless youve cheaped out on tyres on a powerful rwd car, id have thought they would almost certainly be Y rated, which is good for 300kph.

Or are they on winters or something?

Possible theyre W, in which case thats still good to 270kph.

Anything less than W shouldn't be on the car.

Also why is the windscreen telling you what speed to do? Have you got some speed limiter set or something? But yeah, if tyres are W or Y rated, crack on at 250kph.

Edited by brillomaster on Friday 6th November 03:47

[ST3.14159265358979323846]

These are either H rated winter tyres or the winter tyre limiter has been set.

ETA: The tolerance is whatever the speedo is out compared to actual road speed. If you have an accident and are found to have exceeded the limit of the tyre you don't want to go there.
Check what tyres are on the car and go from there.

Edited by ST3.14159265358979323846 on Friday 6th November 05:59

[SkinnyPete]

A tyre’s speed rating tells you what it’s been tested and certified to handle under specific laboratory conditions. It doesn’t mean it’s guaranteed to sit at that speed indefinitely in the real world.

I know that doesn’t really answer your question, but it’s something to keep in mind.

[MB140]

I’m assuming it’s a hire car. If you rented it in Germany then I’m pretty sure it’s illegal to fit the wrong tyre speeds over there.

My brother has lived in Germany for 15 years now. He’s always saying how strict the Germans are compared to back in the uk when it comes to cars and safety etc.

I’d be amazed if the hire company fitted the wrong tyres.

[fourthpedal]

MB140 said:

I m assuming it s a hire car. If you rented it in Germany then I m pretty sure it s illegal to fit the wrong tyre speeds over there.

My brother has lived in Germany for 15 years now. He s always saying how strict the Germans are compared to back in the uk when it comes to cars and safety etc.

I d be amazed if the hire company fitted the wrong tyres.

I'm fairly sure they're allowed to fit higher speed tyres (than the papers specify).

And if the rental company put in a 210 sticker, then they presumably aren't going to fit tyres rated lower than 210, but that doesn't mean they won't be faster.

This time of year the car is likely already on winters or all-seasons, but I honestly don't know what date they'd switch over.

Edited by fourthpedal on Friday 6th November 14:06

[SuperPav]

If you look in the owners manual I suspect that on the tyre specifications table it will have the winter tyre size and rating listed with an H.

That is why they will put the 210kph sticker on (legal requirement where winter tyre speed rating is lower than maximum vehicle design speed).
I think Mercs have this in the actual driver's cluster (i.e. you select Winter tyres, and it automatically limits speed to 210kph with a reminder).

I doubt they'd fit higher rated tyres to the rental car, but even if they do I'd say you're in a bit of a grey area - you technically don't fall foul of the law (unless they're V rated tyres which are good to 240kph, in which case if you don't have a 240kph sticker, you're falling foul of the rules). But you are running the car at higher speeds on winters than it is certified to.


also probably why nobody was overtaking you at 210kph

[Doesitdrive]

Somewhatfoolish said:

I just drove from Frankfurt to Nuremburg and annoyingly windscreen said stay at 210km/h. While I did this and interestingly didn't get overtaken once, when I drive back in a few days time I'd much rather do 250km/h (and it's a 340i so perfectly capable of it), cause I feel it's a moral obligation to use a car properly and set a good example to my daughter.

If the speed codes on the tyres, which I didn't check, turn out to acutally be for 250 (and I don't see why they can't be; my winter tyres in the UK generally are) then I'll just do that. If they however are actually set to 210 then what speed can I actually safely do - I assume there's some sort of margin?

Username checks out, why would you want to put your daughter at risk for a bit of speed?

Even brand new tyres can let go.

[Artsy]

I would check this carefully before attempting this.

Back home (non-UK) we had a really bad accident on the news a few years ago involving a Cayenne that was on winter tyres.

Owner's son decided to show off to a friend by taking it up to 250kph, had a blowout and left the road.

Sadly, he went into a parked car (in a rest area) with a mum and two children in it while dad was in the toilets...

All 3 passengers in parked car dead on collision, plus the two guys in the Cayenne.

Don't even want to think of what that dad went through.