Tyres again (Sorry!) - load/speed ratings

[Waka]

My 40d with 20" staggered setup has eaten its way thorough a set of Dunlop Sport Maxx GT.

I've finally worked out that as I can't get * rated non-runflats and I'm perfectly happy with the ride quality, I'm going for a set of Bridgestone * RFTs.

I have these tyres in my basket and am about to hit the 'buy' button:

Bridgestone Dueler H/P Sport * FR NZ RUNFLAT XL
315/35R20 110Y
for the rears and

Bridgestone Dueler H/P Sport XL RFT HZ *
275/40R20 106W
for the fronts.

I have a tow bar (which I don't use) which is why I guess had the 110 load rated tyres on the back so will still go with that and 106 on the front which is also what I currently have.

What I'm not sure about is the speed rating. Someone on here once suggested not mixing the speed rating of tyres on a car but as Y is rated to 186mph and W is 168mph, surely this can't be a problem?

[Leslie]

Its on the drivers door pillar pal on the tyre rating , mine says 106 front and 110 rear for 20's and mine is a 5 seater .

[X5Sport]

My X6 is the same and I assumed that the larger rear tyre rating was because it was a larger tyre. I also have a tow bar but the vertical load is the same whether it’s the trailer noseweight or the load in the boot. Axle load limit is the same and higher than the front axle so needs a higher load rating.

With regards to different speed indexes, that might be an issue if the tread compounds are softer for one than the other meaning one pair wears faster. The 40d can also deliver a lot of torque so it’s not just about speed - not that I have ever known anyone rip the tread off whilst accelerating

[Waka]

Thanks for the replies gents.

Weirdly the Y rated rears are cheaper than the slower W rated ones.

I'll stop being tight and just buy W rated tyres all round - I'm not going to get over 168mph very often

[JF1980]

Out of interest how many miles did you get out of the Dunlop’s and how did they wear? I’m considering going the other way, from Bridgestone to Dunlop (or Conti) in hope of a better ride.

Presume you have these fitted by now; how would you rate the difference in ride (if any)?

[Waka]

Hi, I got about 17k out of the Dunlops (I think, because they were on the car when I bought it but looked almost brand new then).

The inners on both front and rears were quite badly worn. I got over 30k out of the Toyo Proxes on my old E53, which being non-runflats and 19" were a lot cheaper!

Re.noise, I've only done 1 reasonably long journey so far,but on the concrete bits on the M25 the Dunlops were unbearably noisy and the Bridgestones are a *lot* quieter.

[JF1980]

Not bothered about noise, more interested in softening the ride a bit.

I had the Bridgestones on mine when I got it (about the same time as you I think). I've had 20k out of them and they were not quite new but can't have had more than 5k on them when I got the car. Fronts worn badly on the outside and rears are not too bad on wear (pretty even) but the rubber is starting to perish/crack inside the tread grooves, plus a few large cuts across the tread. Fronts probably would have lasted longer with higher pressure (and less toe-in).

I'm thinking whichever I go for I'll find a specialist and get the alignment done properly, to my spec, theres quite a bit of info on the US forums as to ideal setup for reduced tyre wear.

Agree on 19" E53 tyres. I had some Hankook Ventus on mine which were cheap and performed great. Next set of tyres after this one and I might go non-rfl but for now will stick with (*).