XC90 MPG With Large Wheels?

[tem]

A friend has just phoned me to say that someone in his local club has just recently bought a XC90 D5 and is not happy with his returned mpg.
Around 33 motorway and low 20's in town.

The wheels are 22" and shod with 275/35/R22 Pirelli Scorpion Verde tyres.

Volvo's Quoted mpg:
Urban 45.6 mpg
Extra Urban 52.3 mpg
Combined 49.6 mpg

Does anyone think/know, if these extra large wheels will effect overall mpg?
Thank you.

tem.

[Lexman8]

In theory the diameter should make little difference although the wider tyre and firmer sidewall could have an effect. My guess would be it might make a 5 or 10% difference at most so that wouldn't account for his figures compared to Volvo's. Obviously, anyone would be very lucky to get even close to Volvo's official figures.

The attached pic shows the dimensional differences between his wheel/tyre combination and the 19" wheels on my car. His driving style is likely to be a bigger factor plus it's a new engine and diesels take a few thousand miles to really loosen up.

I've just checked my driving journal for today (VoC is working, woo-hoo!). I drove 10.4 miles from a cold engine start, half urban, half motorway, and got 33.5 mpg. Probably not too different from his really. I suspect a heavy right foot coupled with the small engine/twin turbo setup will drink fuel.
_

[neon]

Originally Posted by Lexman8

In theory the diameter should make little difference although the wider tyre and firmer sidewall could have an effect. My guess would be it might make a 5 or 10% difference at most so that wouldn't account for his figures compared to Volvo's. Obviously, anyone would be very lucky to get even close to Volvo's official figures.

The attached pic shows the dimensional differences between his wheel/tyre combination and the 19" wheels on my car. His driving style is likely to be a bigger factor plus it's a new engine and diesels take a few thousand miles to really loosen up.

I've just checked my driving journal for today (VoC is working, woo-hoo!). I drove 10.4 miles from a cold engine start, half urban, half motorway, and got 33.5 mpg. Probably not too different from his really. I suspect a heavy right foot coupled with the small engine/twin turbo setup will drink fuel.
_

33.5mpg not too bad for mixed driving. May also be if like me with a new car you are trying everything, which does not encourage high mpg. With the reviews I noticed some floored the car then commented on poor mpg.

[Deman77]

Originally Posted by neon

33.5mpg not too bad for mixed driving. May also be if like me with a new car you are trying everything, which does not encourage high mpg. With the reviews I noticed some floored the car then commented on poor mpg.

27 mixed on 20s here. Lots of short trips that register in low 20s. Motorway 20-30miles - very rare - around 40 and B roads mid 30s - I did see about 10% drop (worse) since polestar as that really invites you to press on. Have 22s on loan (no polestar) at the moment and I wouldn't say it's any worse.

[neon]

Originally Posted by Deman77

27 mixed on 20s here. Lots of short trips that register in low 20s. Motorway 20-30miles - very rare - around 40 and B roads mid 30s - I did see about 10% drop (worse) since polestar as that really invites you to press on. Have 22s on loan (no polestar) at the moment and I wouldn't say it's any worse.

Is that the D5, if so not so good.

[Marley Don]

I have a D5 momentum. A few weeks back I drove down to Cornwall with a Volvo roof box - it's the equivalent to the Thule dynamic 800, so not a massive box. Mainly motorway miles.

I was interested to see how much worse the MPG would be with the box/ roof bars on the top. Average MPG read 41.3 which I thought was pretty good. That was doing average motorway speed around 80mph. I would normally get 43-45 MPG on a decent motorway run.

[neon]

Originally Posted by Marley Don

I have a D5 momentum. A few weeks back I drove down to Cornwall with a Volvo roof box - it's the equivalent to the Thule dynamic 800, so not a massive box. Mainly motorway miles.

I was interested to see how much worse the MPG would be with the box/ roof bars on the top. Average MPG read 41.3 which I thought was pretty good. That was doing average motorway speed around 80mph. I would normally get 43-45 MPG on a decent motorway run.

That is not bad at all. How many people in the car.

[Lexman8]

I drove up to Leeds this morning. Journal says 13 miles (of which 7 were motorway) and I averaged 41 mpg. I'd guess the actual motorway stretch while doing 65-70 mph with Pilot Assist was around 45 mpg, maybe a bit more.

Coming back during rush hour I averaged 37 mpg. I think the mpg on both journeys is perfectly acceptable for such a large beast of a car.

[neon]

Originally Posted by Lexman8

I drove up to Leeds this morning. Journal says 13 miles (of which 7 were motorway) and I averaged 41 mpg. I'd guess the actual motorway stretch while doing 65-70 mph with Pilot Assist was around 45 mpg, maybe a bit more.

Coming back during rush hour I averaged 37 mpg. I think the mpg on both journeys is perfectly acceptable for such a large beast of a car.

Yes I would agree that is pretty good and realistic. Are you light on the right foot.

[Lexman8]

Originally Posted by neon

Are you light on the right foot.

I think about driving economically/sensibly but I don't drive like an old lady. Equally, I don't do a racing start at every set of lights. Just a normal driving style I'd say.