diesel economy

[Cole]

Originally Posted by powers1

Aerodynamics/Rolling resistance/drag /weight of a 20" wheel/tyre set up is always superior than 17" set up,irrespective of tyre tread..
I noticed an immediate increase in fuel consumption when I went up from my standard 19"s!

hmmmm... I am not entirely convinced that your increase in consumption is solely to do with the change from 19" to 20" setup. Exactly what size tyres are you running on your 20".s? Did you also re-check your wheel alignment when you upgraded? IMO I don’t think that the tyres should have made that significant a change to your consumption if you matched the correct circumference and have correct wheel alignment.

I also have Pirelli Scorpion ATR’s but I opted for an increased rolling circumference (for better ground clearance) and this has thrown my indicated consumption, as per the trip computer, out by 5%, but adjusting for that my consumption is much the same as before.

[Fraser]

Originally Posted by Cole

[I also have Pirelli Scorpion ATR’s but I opted for an increased rolling circumference (for better ground clearance) and this has thrown my indicated consumption, as per the trip computer, out by 5%, but adjusting for that my consumption is much the same as before.]

Cole,

What size ATR have you fitted?

[bigwave2255]

have any of you noticed also that your speedo reads 5 kmph (or 6) faster at all speeds, my gps is telling me that when i am doing 100 kmh on the speedo im really doing 94.

it doesnt seem to effect the total counter, that i can tell

Ewen

[Cole]

Hi Fraser, I fitted 265/65/17 ATR's... remember we had this discussion before in the thread below ;-)http://www.xoutpost.com/bmw-sav-foru...cs-2.htmlStill very happy with the Scorpions, have done 15,000kms on them and they still look good. Haven't had to do much 4x4 stuff, but I have lauched the boat in mud a few times and they do seem to grip much better than the old Mitchelins...

[Fraser]

Originally Posted by Cole

Hi Fraser, I fitted 265/65/17 ATR's... remember we had this discussion before in the thread below ;-)http://www.xoutpost.com/bmw-sav-foru...cs-2.htmlStill very happy with the Scorpions, have done 15,000kms on them and they still look good. Haven't had to do much 4x4 stuff, but I have lauched the boat in mud a few times and they do seem to grip much better than the old Mitchelins...

Cole,

Yep, I remember our long discussion on this matter. I just couldn't recall what size you had fitted. I'm also very happy with my Scorpion ATRs.

[Cole]

Originally Posted by bigwave2255

have any of you noticed also that your speedo reads 5 kmph (or 6) faster at all speeds, my gps is telling me that when i am doing 100 kmh on the speedo im really doing 94.

it doesnt seem to effect the total counter, that i can tell

Ewen

Yes I have looked into this quite a lot as I have over size tyres and I wanted to know the effect it would have on my readings etc. The odometer and the trip computer seem accurate, but the actual speedo overreads by +/-5%. But this is normal and in previous discussions it has generally been agreed that this is a safety factor implimeted by most vehicle manufacturers.

[powers1]

Originally Posted by Cole

hmmmm... I am not entirely convinced that your increase in consumption is solely to do with the change from 19" to 20" setup. Exactly what size tyres are you running on your 20".s? Did you also re-check your wheel alignment when you upgraded? IMO I don’t think that the tyres should have made that significant a change to your consumption if you matched the correct circumference and have correct wheel alignment.

I also have Pirelli Scorpion ATR’s but I opted for an increased rolling circumference (for better ground clearance) and this has thrown my indicated consumption, as per the trip computer, out by 5%, but adjusting for that my consumption is much the same as before.

If you read my earlier post carefully,you will notice that I already mentioned that I am running the oem 20" staggered set up,so from this you should know what tyres I am running
My car is properly maintained by yours truly and working at the dealer obviously helps
With regards to your--"hummmm...not convinced",then maybe you are right,maybe its not because I am running bigger tyres...its because I have a diesel leak thats increasing my consumption..and maybe I also got it wrong with my other cars that also increased fuel consumption whenever I upped the wheels.
..and maybe you should learn to accept peoples feedback.because I have nothing to gain in lying here..What I say is simply my feedback and anyone that tells you that running 17 or 20s and the fuel consumption is the same,then you can say "hummmm....I am not convinced"!
Have a good day mate...