New RR 20” wheels - terrible MPG!!!!

[Jay Grundy]

Hi there - some advice please - I have the baby engined T6 bluemotion - and I've just fitted a gorgeous set of carbon dipped Range Rover 20's to it with 275/40/20 tyres - first run into work today and my mpg at 70 has dived from near 50 to low 30's - now obviously the only change is the rims etc but should I really see such a dramatic drop in mpg - is there anyway to still run 20's with maybe a better tyre to bring it back up a bit??? Cheers Jay

 

[Roadrunner]

Yes drive slower and take you foot off the gas

 

[Jay Grundy]

Think you need to change your name from GURU!!!

 

[Roadrunner]

Think you need to change your name from GURU!!!

Sorry I take it you don't like me joking then

 

[Loz]

Hi there - some advice please - I have the baby engined T6 bluemotion - and I've just fitted a gorgeous set of carbon dipped Range Rover 20's to it with 275/40/20 tyres - first run into work today and my mpg at 70 has dived from near 50 to low 30's - now obviously the only change is the rims etc but should I really see such a dramatic drop in mpg - is there anyway to still run 20's with maybe a better tyre to bring it back up a bit??? Cheers Jay

Are you using the memory 1 or memory 2 (long term) in your MFD or are these brim to brim calculations?

 

[Pauly]

Defo think its worth manually calculating your MPG tank to tank and see what the actual figure are, some people find the onboard readings to be way out

 

[RattyMcClelland]

I had various different sizes of wheels on my t5 and went from 235/55/17 to 275/40/19 and saw no difference in fuel economy.

However I have to drive ever so carefully and slow to get any decent mileage out of the t6.

Despite my mid saying 37mpg I hold judgement until I use a full tank. Highest yet is 30.7mpg.

 

[Jay Grundy]

Sorry I take it you don't like me joking then

Losing 25% of fuel economy ain't no laughing matter ha ha - jay

 

[Jay Grundy]

Are you using the memory 1 or memory 2 (long term) in your MFD or are these brim to brim calculations?

I've got instantaneous mpg and average (think it's on last journey) I'm gonna do 4 x 60 mile work runs to get a good base reading thanks

 

[former member]

More drag, more strain on drivetrain, more weight.
Why oh why not stick to what is designed for the van?!!

 

[Jay Grundy]

Does anyone know if there is a low resistance good fuel economy tyre in 20 inch sizes!?????

 

[Teejay1]

I have read somewhere on the web about how larger wheels can decrease the MPG but it was not by a great deal.

..me..

 

[Roadrunner]

Think my first step would be to change back to the original wheels & tyres and see the figures then and see if there is a difference, it may well not be the wheel & tyres. VW only go up to 18" ATM every one seems to want to change to 20" wheels

 

[Jay Grundy]

My overall height is not a million miles away from original size - I've just seen some continental ECO tyres that are 195/55/20 and these are same overall height as my 275/40/20 but they are narrower and an ECO tyre - might be worth the £450/4 over the £260 I just paid - I'm sure losing nearly 20mpg on every gallon the continentals will pay for themselves in no time - jay

 

[Roadrunner]

You could try messing around with this to check
Tyres & Alloys Wheels Tyresave

 

[T6 Dave's Dad]

@Jay Grundy You may have found the answer. Circumference of the tyre is more important than height, coupled with narrower cross section and lower rolling resistance rubber will give an improvement. Cost/benefit analysis is required, not forgetting anticipated life expectancy of each.

 

[Chopman]

Jay, if it really is that bad, why not consider going down slightly to a 19" wheel?
TBH, some 19" wheels look as big as some 20"s.

What width are your wheels? If you have 275 on them now, they are unlikely to take 195's.

- edit -

A 275 tyre will fit a rim width of 9.5" min to 11" inch
A 195 tyre will fit a rim width of 5.5" min to 7" max
Tire Width for a Wheel/Rim Size Chart

 

[Roadrunner]

@Jay Grundy your wheels come in at & tyres come in at 28.66 diameter my 18" are 27.4 I would think your old 16" were a similar diameter that could be the cause of your MPG probelm

 

[Jay Grundy]

@Jay Grundy your wheels come in at & tyres come in at 28.66 diameter my 18" are 27.4 I would think your old 16" were a similar diameter that could be the cause of your MPG probelm

I thinks it's gonna come down to running the narrowest ECO TYRE I can to get somewhere back to start point

 

[Roadrunner]

Try sticking the old ones back on first and get a reference before you spend more money. It will be more likely the OD not the width causing it