Tyre speed ratings and the law
08-09-2012, 12:18 AM
#12
Community Organizer
May I also make a physics point? Just to confuse a few of you...
Earlier in this thread richmc said the speed ratings of the tyres are:
W = 168mph V = 149mph
Did you know: if your car is travelling at 168mph then the top of the tyre is going twice this speed (336mph) in a forward direction?
So the so called "Speed Ratings" are actually accelleration and decelleration tollerances.
Knowing this you will always spend more on tyres than any other part of your car. I have never bought cheap tyres.
Minvo.
Earlier in this thread richmc said the speed ratings of the tyres are:
W = 168mph V = 149mph
Did you know: if your car is travelling at 168mph then the top of the tyre is going twice this speed (336mph) in a forward direction?
So the so called "Speed Ratings" are actually accelleration and decelleration tollerances.
Knowing this you will always spend more on tyres than any other part of your car. I have never bought cheap tyres.
Minvo.
08-09-2012, 02:39 AM
#13
Originally Posted by richmc' timestamp='1344460038' post='21922821
The wrong tyres are truly awful! 
That said, it does sound like the dealer (and I pressume B'pool Homda is a franchised Honda outlet) has stiffed the OP with the cheapest crap they could find - I bet they would have had any number of good reasons for a punter to buy Potenzas from them at some ridiculously inflated price if you went in for a service or MoT.
I've never heard of a franchised dealer fitting non-OEM parts before; is it common? It's like finding out they've fitted a Halfords oil filter during your service........
Anyway, I'd use the fact that the tyres don't meet Honda's own recommendations as the arguement for having the dealer replace them with something not so cheap and nasty. Stand firm and be a pain in the arse until they comply!
I bet if you complained about a sticking caliper they would stiff you full Honder price rather than an eBay refurb. At the very least they should be using what Honda recomend regarding tyres, and don't let them fob you off with they don't make them any mor, they do.
Coldfuse said - If the tyres are legal i doubt they will give a monkeys tbh
As a secondhand car to be legal it must be sold in a safe state, not just with an MOT, if it's shown not to be up to it's complience certification then it's safety has been compromised and therefore not legal.
08-09-2012, 04:03 AM
#14
Registered User
May I also make a physics point? Just to confuse a few of you...
Earlier in this thread richmc said the speed ratings of the tyres are:
W = 168mph V = 149mph
Did you know: if your car is travelling at 168mph then the top of the tyre is going twice this speed (336mph) in a forward direction?
So the so called "Speed Ratings" are actually accelleration and decelleration tollerances.
Knowing this you will always spend more on tyres than any other part of your car. I have never bought cheap tyres.
Minvo.
Earlier in this thread richmc said the speed ratings of the tyres are:
W = 168mph V = 149mph
Did you know: if your car is travelling at 168mph then the top of the tyre is going twice this speed (336mph) in a forward direction?
So the so called "Speed Ratings" are actually accelleration and decelleration tollerances.
Knowing this you will always spend more on tyres than any other part of your car. I have never bought cheap tyres.
Minvo.
Do explain
08-09-2012, 04:12 AM
#15
Community Organizer
OK.
So to start...
Question: How fast it a car tyre going at the point it touches the ground?
Answer: ZERO MPH (it is not moving - otherwise you would be skidding!)
Ever wondered why you get a wet back when cycling through a puddle?
Reason: The top of the tyre/wheel is going faster than you and throws the water onto your back as the centrifugal force puches it outwards)
So to conclude...
The tyre is not moving at the bottom. It is however doing double speed at the top.
Therefore the tyre has to accelerate from zero to double your speed on the way up... and
Decelerate from double speed to zero on the way back down to the ground.
This acceleration and deceleration causes a lot of pulling and pushing on the tyre.
Add in the centrifugal forces involved in the spinning of the wheel then they do take some punishment.
Hope this helps you to decide not to buy budget tyres.
Minvo
So if you get this then answer me another question.
If a car is travelling at half the speed of sound then are it's wheels breaking the sound barrier?
So to start...
Question: How fast it a car tyre going at the point it touches the ground?
Answer: ZERO MPH (it is not moving - otherwise you would be skidding!)
Ever wondered why you get a wet back when cycling through a puddle?
Reason: The top of the tyre/wheel is going faster than you and throws the water onto your back as the centrifugal force puches it outwards)
So to conclude...
The tyre is not moving at the bottom. It is however doing double speed at the top.
Therefore the tyre has to accelerate from zero to double your speed on the way up... and
Decelerate from double speed to zero on the way back down to the ground.
This acceleration and deceleration causes a lot of pulling and pushing on the tyre.
Add in the centrifugal forces involved in the spinning of the wheel then they do take some punishment.
Hope this helps you to decide not to buy budget tyres.
Minvo
So if you get this then answer me another question.
If a car is travelling at half the speed of sound then are it's wheels breaking the sound barrier?
08-09-2012, 04:46 AM
#16
Community Organizer
08-09-2012, 05:10 AM
#17
Registered User
Originally Posted by WinFreak' timestamp='1344513805' post='21924113
Do explain
So to start...
Question: How fast it a car tyre going at the point it touches the ground?
Answer: ZERO MPH (it is not moving - otherwise you would be skidding!)
Ever wondered why you get a wet back when cycling through a puddle?
Reason: The top of the tyre/wheel is going faster than you and throws the water onto your back as the centrifugal force puches it outwards)
So to conclude...
The tyre is not moving at the bottom. It is however doing double speed at the top.
Therefore the tyre has to accelerate from zero to double your speed on the way up... and
Decelerate from double speed to zero on the way back down to the ground.
This acceleration and deceleration causes a lot of pulling and pushing on the tyre.
Add in the centrifugal forces involved in the spinning of the wheel then they do take some punishment.
Hope this helps
Minvo
So if you get this then answer me another question.
If a car is travelling at half the speed of sound then are it's wheels breaking the sound barrier?
Some of what you said is sort of correct, but for the wrong reasons
08-09-2012, 06:48 AM
#18
Actually the tyre is not moving at the top or the bottom, it's the car thas moving. To get your head round that one think of standing on a tank track whilst the tank is moving, you dont move relative to the track at the bottom till you fall off the end, tank tracks go up and down.
08-09-2012, 07:33 AM
#20
I work in a Honda Dealer and forgetting the science behind the actual tyre speed and any "law" which may apply that is bloody piss poor customer service, they probably only saved about £50 each tyre, I would speak to the manager and demand they change the tyres, bet they do.
Good Luck.
Cheers.....Tony..
Good Luck.
Cheers.....Tony..