Bora TDI Alloy Wheels Vs. MPG

[Nickellese]

HI Guys

I've had my 110 TDI Bora for a few months now and thus far it has served me very well.

Last week i had the waterpump/cambelt changed at VW because the waterpump was not cooling the car suffiently causing the car to run to hot.

The day after i swapped the wheels over from the standard steels to a set of beetle alloys because the tyres desperately needed changing.

Since then the MPG has seen a fall and i think(!) it feels abit more sluggish. On a motorway trip even at 90 the MPG would never dip below 57 now at 70 i struggle to get over 51

The alloys are the same diameter as the ones they replaced but are slightly wider. Admittedly they are probably slightly less aerodynamic and a fraction heavier but still!

Surely if they were designed to use with the beetle my bora should be fine?

A friend suggested it could be the MAF, or worse still VW could have got the timing wrong?!?

Anyways any advice would be appreciated.

Thanks in advance

--

[cruiser647]

Could be that the rolling diameter of the wheels has changed the speedo readings. There is a way of working out what size wheel/tyre combo should replace the originals.

So, not all 16" wheels with tyres have the same rolling diameter.

[Nickellese]

Sorry should have said, Wheels including tyres are the same diameter.

[cruiser647]

Can you let us know the exact tyre size of both old and new please.

A 195/55 R16 does not have the same rolling diameter as a 225/55 R16... for instance.

[Rustynuts]

Put the old ones back on for a test drive and see if the mileage improves.

[pingpongpo]

I would also take the computer readout with a pinch of salt as they aren't the most accurate thing in the world.

The only real way of measuring true MPG is doing the old filling up from empty method and then doing the same again once you have emptied the tank.