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Re: Putting a thinner tyre on the back 4.6is

Posted: Wed Dec 05, 2012 5:40 pm
by Don Coffey
[quote="IanP"]
I always understood that the 4.6 has the big brakes as mentioned so you will need 19'' wheeels
[/quote]

I knew they had big brakes, just didn't realise how big.  ::)

Sorry for the bum steer towards squeakies wheels!  :'(

Don

Putting a thinner tyre on the back 4.6is

Posted: Wed Dec 05, 2012 6:01 pm
by kkodal78
18s are the smallest you can put on is models

Putting a thinner tyre on the back 4.6is

Posted: Wed Dec 05, 2012 6:03 pm
by kkodal78
[quote="dgm"]
Don't be put off putting on 20" winters, I've just done it and the car has been superb in the snow and ice.  I've gone with a higher profile than the standard 20" sizes but the Yokohama winters come in non runflat in the OEM sizes. 

I'm on Pirelli Ice and Snow in 295/45/20 and 265/50/20 sizes.  You could go 295/40/20 and 275/40/20 successfully
I think, however, I haven't personally tried that combination.
[/quote]
Those dimensions seems a little off. Your odometer reading might be off with the numbers above

Re: Putting a thinner tyre on the back 4.6is

Posted: Wed Dec 05, 2012 6:15 pm
by dgm
[quote="kkodal78"]
[quote="dgm"]
Don't be put off putting on 20" winters, I've just done it and the car has been superb in the snow and ice.  I've gone with a higher profile than the standard 20" sizes but the Yokohama winters come in non runflat in the OEM sizes. 

I'm on Pirelli Ice and Snow in 295/45/20 and 265/50/20 sizes.  You could go 295/40/20 and 275/40/20 successfully
I think, however, I haven't personally tried that combination.
[/quote]
Those dimensions seems a little off. Your odometer reading might be off with the numbers above
[/quote]

Yes, higher profile than standard so the speedo is now more or less in line with the GPS speed as opposed to the usual over estimation of actual speed.

Putting a thinner tyre on the back 4.6is

Posted: Wed Dec 05, 2012 6:19 pm
by kkodal78
That may not be good for your all wheel drive and abs calculations though.please correct me if am wrong but i thought slower or faster than oe size is not good for gearbox etc

Re: Putting a thinner tyre on the back 4.6is

Posted: Wed Dec 05, 2012 6:22 pm
by Don Coffey
[quote="dgm"]
[quote="kkodal78"]
[quote="dgm"]
Don't be put off putting on 20" winters, I've just done it and the car has been superb in the snow and ice.  I've gone with a higher profile than the standard 20" sizes but the Yokohama winters come in non runflat in the OEM sizes. 

I'm on Pirelli Ice and Snow in 295/45/20 and 265/50/20 sizes.  You could go 295/40/20 and 275/40/20 successfully
I think, however, I haven't personally tried that combination.
[/quote]
Those dimensions seems a little off. Your odometer reading might be off with the numbers above
[/quote]

Yes, higher profile than standard so the speedo is now more or less in line with the GPS speed as opposed to the usual over estimation of actual speed.
[/quote]

Now I have no knowledge of the physics involved, but surely having both front and rear tyres with the same ratio could cause problems, as this in essence will mean the rear diameter is bigger than the front.

Don

Re: Putting a thinner tyre on the back 4.6is

Posted: Wed Dec 05, 2012 7:12 pm
by dgm
[quote="kkodal78"]
That may not be good for your all wheel drive and abs calculations though.please correct me if am wrong but i thought slower or faster than oe size is not good for gearbox etc
[/quote]

I posed the question here before going ahead with these sizes but no one put up any evidence that the 6% increase in diameter would have an adverse effect on the gearbox.  My winter sizes seem to have been commonly used in the USA with no detrimental effects.  The car is actually very enjoyable to drive with a bit more sidewall and if there are any negative effects on the ABS then I haven't detected them, it still works exactly as it should.

The rolling radius front and back is spot on and I believe that's the most important factor here.

Re: Putting a thinner tyre on the back 4.6is

Posted: Thu Dec 06, 2012 11:30 am
by Raj
As you've stated, there isn't an issue as long as both front to rear rolling radius is kept the same. So although you have moved slightly from stock sizes you've kept front/back same so no real problem. The running fear etc is still performing the same physical cycle front to rear also. Tbh you are talking millimetres too in difference so not exactly huge margins of difference. It's like having worn tyres on one axle near the legal limit and brand new tread on the other axle. Difference in diameter is similar kind of margins. You'd be surprised in the difference between different makes also.

Re: Putting a thinner tyre on the back 4.6is

Posted: Thu Dec 06, 2012 1:52 pm
by gobiman
Just to confirm, 17s will not fit over the front brakes on a 4.6/4.8 which is why I'm on 18s. These are the BMW recommended alloys which I have on (same size all round) -

http://www.ebay.de/itm/BMW-X5-E53-Winte ... 2325ce4d34

Re: Putting a thinner tyre on the back 4.6is

Posted: Thu Dec 06, 2012 2:19 pm
by Raj
[quote="gobiman"]
Just to confirm, 17s will not fit over the front brakes on a 4.6/4.8 which is why I'm on 18s. These are the BMW recommended alloys which I have on (same size all round) -

http://www.ebay.de/itm/BMW-X5-E53-Winte ... 2325ce4d34
[/quote]

My German isn't very good, but will they ship to the UK? As currently 22 Euros???

Re: Putting a thinner tyre on the back 4.6is

Posted: Thu Dec 06, 2012 2:47 pm
by gobiman
I found mine on ebay.de. (admittedly a dealer rather than private punter).
Always worth asking.
Cut and paste with google translate.
Bought some skiis last week from Milan off ebay.it which were over £100 cheaper than UK and only cost 10 euro to ship.

Re: Putting a thinner tyre on the back 4.6is

Posted: Thu Dec 06, 2012 3:44 pm
by Don Coffey
I have looked at wheels from German ebay as well, but wheels are very heavy and as such could be expensive to get across.  The best price I could find was £120 for a pallet.  Now that was to Northern Ireland, but the issue was getting the seller to agree to put on pallet.  Google translate is limited when trying to portray the grammar.

Don

Re: Putting a thinner tyre on the back 4.6is

Posted: Thu Dec 06, 2012 5:01 pm
by gobiman
If a German dealer is prepared to have them delivered in Germany (and quotes a price), there is no major drama (for him) in simply getting a different price from his shipper for the UK which will be someone like DHL.
I've been pleasantly surprised at how reasonable freight costs can be - think I only paid an extra 50 euros from a garage in Munich and they arrived the next day having been delivered overnight to a warehouse in the Midlands.
I'm told (by a German) that the Germans don't like shipping to Eastern Europe so don't generally quote for international delivery.

Re: Putting a thinner tyre on the back 4.6is

Posted: Thu Dec 06, 2012 5:51 pm
by Don Coffey
[quote="gobiman"]
If a German dealer is prepared to have them delivered in Germany (and quotes a price), there is no major drama (for him) in simply getting a different price from his shipper for the UK which will be someone like DHL.
I've been pleasantly surprised at how reasonable freight costs can be - think I only paid an extra 50 euros from a garage in Munich and they arrived the next day having been delivered overnight to a warehouse in the Midlands.
I'm told (by a German) that the Germans don't like shipping to Eastern Europe so don't generally quote for international delivery.
[/quote]

Totally agree that getting from a dealer should be trouble free and they should have the contacts for decent freight charges.  I am pointing out the implications of dealing with a non commercial seller.

Don

Putting a thinner tyre on the back 4.6is

Posted: Thu Dec 06, 2012 6:40 pm
by kkodal78
Dpd is fairly reasonable getting stuff from germany. They are quick as well