View Full Version : Speed rating of tyres on A4 Avant TDIe
YawnGumbo
07-01-2014, 02:50 PM
I replaced the front tyres on my TDIe 136 before Christmas with Kwik Fit (had no choice as its a company car so can only use Kwik Fit). I asked for them to be replaced with ContiSportContact 3's which are exactly the same as what it came out of the factory with. It took them 2 attempts to get the correct tyres in to stock, but it wasn't until I checked afterwards that I've noticed they've put on ContiSportContact 2's rather than the 3's and they have put 94W's rather than 94Y's. I have checked the manual and the Audi website and both state it should be a 94Y. I asked Kwik Fit about this when I took the car back to have its wheels balanced as I was getting steering wheel wobble and they said well W's are pretty much the same as Y's so it will be fine. I took the car out for a long run yesterday and noticed I was still getting the wobble, but also that my fuel economy was way down (usually on this run I get around 54mpg indicated, I got 44mpg yesterday doing the same speeds as usual). Now this could be down to the weather conditions as it was pretty windy, but none of this seems quite right.
Just wondering what your views/experiences are on having a different speed rating, and if I should push harder with Kwik Fit to get them changed. Do you think the fuel economy thing is just coincidence? I'm yet to talk to my leasing company to see if there are any insurance concerns.
Thanks.
zollaf
07-01-2014, 03:23 PM
w is 168 mph, y is 186 mph. the speed rating is not your problem, they just need balancing properly.
YawnGumbo
07-01-2014, 06:34 PM
Had them rebalanced on Sunday, but it made no difference. Think I might try a different Kwik Fit and see if that makes any difference!
DrNorthy
07-01-2014, 06:53 PM
My car came out of the factory with the 3's on had them replaced at Kwik fit (company car) and they put the 2's on I have had no problem with fuel consumption stayed the same.
YG, forgive me for asking an obvious question, but have you checked what air pressure the supplier has put in your new tyres? It might have an effect upon your fuel consumption.
YawnGumbo
08-01-2014, 02:43 PM
Yup one of the first things I did as I needed to reset the TPMS so went to a garage and confirmed all pressures were correct. Obvious questions welcome though! :)
DrNorthy - were they the W's or Y's that were put on your car?
Think I just need to get this wheel wobble sorted and then hope the fuel consumption gets better.
markp306
08-01-2014, 11:42 PM
Yup one of the first things I did as I needed to reset the TPMS so went to a garage and confirmed all pressures were correct. Obvious questions welcome though! :)
DrNorthy - were they the W's or Y's that were put on your car?
Think I just need to get this wheel wobble sorted and then hope the fuel consumption gets better.
i had this same problem twice (!) with ATS and it was because the weights had immediately fallen off. I got Audi to sort it out and everything was fine, so try getting them balanced somewhere completely different?
I doubt the speed rating is relevant as long as the load index is appropriate. On my previous B8 I used 98Z (extra load) with no noticeable difference.
sportq
10-01-2014, 04:10 PM
Have you check if any the wheels are buckled? I wouldn't put it past Kwik-fit not to notice. My car had vibration at 70mph which Audi identified as a buckled front wheel which they found during a service. They moved it to the back at and it virtually disappeared (I've since replaced the alloy). It could be that a back wheel was buckled and got switched to the front when the new tyres were fitted.
Peter
sprint
10-01-2014, 05:40 PM
Is not your insurance affected if you do not have the manufactures specified tyres, 94Y's instead of the 94W's that Kwik fit have fitted, in the event of any accident claim?
Wobert
10-01-2014, 05:52 PM
No, the speed rating of the tyre has to be in line with the max speed of the car. A 136 TDie has a vmax of 130 mph so the tyre speed rating has to exceed this. In this case you could use a V-rated tyre as at 150 mph this also exceeds thevamx of the vehicle.
In a lot of cases the tyre manufacturers limit the number of speed ratings thay make for a given tyre type and size, so usually go with ratings that are towards the top end of those vheicles they will be used on.
As others have pointed out, the load index is a much more critical number to match correctly.
sprint
10-01-2014, 06:33 PM
No, the speed rating of the tyre has to be in line with the max speed of the car. A 136 TDie has a vmax of 130 mph so the tyre speed rating has to exceed this. In this case you could use a V-rated tyre as at 150 mph this also exceeds thevamx of the vehicle.
In a lot of cases the tyre manufacturers limit the number of speed ratings thay make for a given tyre type and size, so usually go with ratings that are towards the top end of those vheicles they will be used on.
As others have pointed out, the load index is a much more critical number to match correctly.
Thanks for the reply and clarification.
I have always been led to believe, certainly by most tyre dealers, that you have to maintain the original manufactures fitted speed rating.
So why on earth do manufactures fit tyres that are some two or more speed ratings above the actual max speed of the car?
Are the characteristics of the lower rated tyres, grip, noise, wear etc significantly worse than those of the higher rated tyres to justify the extra cost they very often demand?
zollaf
10-01-2014, 07:53 PM
the speed rating is basically the max speed the tyre can go at for prolonged periods before it falls apart. it is strange that a tyre maker will produce a tyre to travel at 168 mph though.
incidentally, there is no legal requirement to have tyres of any speed rating on any car, so you could stick h's on a veyron. if the driver exceeds the limit of the tyre, thats where the problem starts. but why we need anything over 70 in this country is just laughable. of course, a y rated tyre is a lot more money than an h.
YawnGumbo
13-01-2014, 07:28 PM
Thanks for all the replies. I took the car back to Kwik Fit on Sunday and got the tyres balanced again. Journey home and they seemed a bit better. I'm driving down south this weekend in it so we'll see if it makes any difference and if the mpg is any better. Fingers crossed!
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