Would give more mpg for higher gearing ?

Always seems low geared anyway :wonder: ,

and speedos usually read high anyway :wonder: .

And speed checks add on 10% plus a bit to allow for inaccuracies they say

What would be the alternatives ?

And the consequencies ?

Well, the standard gearing is good for 120mph at 6,000 rpm, I think, can't see that the standard engine will pull much higher. Higher gearing would give higher MPG if all else was equal, but you may end up using more fuel accelerating 'harder' (i.e. pressing the pedal down all the time) so you may not gain anything, but then again you may do - I think it would depend on a lot of things including your driving style. C&U regs give a 10% over-read capacity on speedos, but NO under-read. I believe that the ACPO guidelines are 10%+2mph for speeding, but they can do you for anything above the speed limit.

Alternatives - higher gearing with a diesel final drive, but that's a LOT taller.

Consequences - a jacked up car that handles badly, messed up steering, wheels rubbing on the arches at some points (my rally car runs 80 profile tyres on gravel and they sometimes foul the rears of the front arches when turning and braking), invalid insurance if it's a non-approved overall size (extreme, but you never know!)

the problem would be that the engine would not have enough torque to make use of the bigger rolling diameter of the wheels, the mpg would be reduced i'd imagine becuase you would need to use more throttle at a lower rpm to get the same wheel speed.

the best alternative is to sell up and buy a diesel, there's no magical way of gaining more economy otherwise skoda would have done it to start with