tires

[tommyt2]

Im just wondering if anyone here hes ever tried putting a 245/40/18 tire on their a4 i have 18s with 235/35/18 and would like more comfort so if any body has any info or experience would love to know......

 

[dstech]

Here in the States we get 235/40/18 for stock 18" wheels.
I'm sure you could go 245/40/18 but your tire will be bigger in diameter, you'll need to make sure your wheel width can handle it, and of course your speedo will be off bit (going faster than you think).

If I were you I'd just get 235/40/18's and call it a day.
BTW, with you having 235/35/18's on your B6 now, you're speedo is off a bit so you're actually going slower than you think. For instance with the tires you have on right now when your speedo reads 103km/hr you're actually going 100km/hr. On the other hand if you get 245/40/18's then your speedo will read 98.4km/hr when you're actually going 100km/hr.

So the tires you have on now are actually worse than going to 245/40/18. You need at least an 8"-9.5" wide wheel.

 

[Macduff]

BTW, with you having 235/35/18's on your B6 now, you're speedo is off a bit so you're actually going slower than you think. For instance with the tires you have on right now when your speedo reads 103km/hr you're actually going 100km/hr. On the other hand if you get 245/40/18's then your speedo will read 98.4km/hr when you're actually going 100km/hr.

And that assumes the speedo is correct to start with. My B6 on 235/45R17s overreads by about 3mph up to 70mph and by 100mph the error is about 4mph. Not too bad as my VFR800 is only doing 100mph when it reads 109mph.

I verified this with GPS on a straight flat road so it should be accurate.

Dave