Wheel size v Road Tax

[markjay]

guys hi, new here, quick question since all posts above from 2015... I plan to buy diesel 2 liter c class, lets say for example c250d 2017 model amg line trim.. what would be the difference of tax between 17" wheels compared to 19" wheels or even 20! if i retro fit later.?? thanks alot

There's no difference in tax if you retrofit the bigger wheels later.

And it's very difficult to say what would be the difference in tax if the bigger wheels were factory fitted from new - this will depend on whether the bigger wheels 'pushed' the emissions into a higher tax bracket or not, which will in turn depend on the car's other features as ordered....

 

[shopar]

There's no difference in tax if you retrofit the bigger wheels later.

And it's very difficult to say what would be the difference in tax if the bigger wheels were factory fitted from new - this will depend on whether the bigger wheels 'pushed' the emissions into a higher tax bracket or not, which will in turn depend on the car's other features as ordered....

thanks, make sense, how about if i retro fit , then should i inform the insurance, i mean technicaly i should inform everything to the insurance lets be honest ....

 

[markjay]

thanks, make sense, how about if i retro fit , then should i inform the insurance, i mean technicaly i should inform everything to the insurance lets be honest ....

Yes, you should inform your insurer, and it may affect your premium (though, as said, it won't affect the VED).

 

[renault12ts]

thanks, make sense, how about if i retro fit , then should i inform the insurance, i mean technicaly i should inform everything to the insurance lets be honest ....

If you buy a car used...do you check it has the wheels it left the factory with?

 

[Gazwould]

Welcome to the dynamics of unsprung mass .

 

[Petrol Pete]

Take a look at old 'eco' cars ,I can't remember the details but years ago I worked with a guy who had a Vauxhall Astra similar to the one I was driving at the time and there was something 'wrong' about the way it looked compared to the one I had. He pointed out the tall skinny wheels on it and told me it was an 'eco' model and if I remember they tyre pressure he had to use was very high.

But it's obvious tall skinny wheels create less friction , take a look at a BMW i3 , got something like 20 inch X 5 inch rims. The wheel size in relation to tax bracket will almost certainly be emissions related.

On older cars the date they were registered can make a huge difference , take my own C55 2006 = £580 pa , 2005 £330 pa , same car , the only discernible difference as I can see is mine has flappy paddles and the slightly older version has push buttons on the steering wheel.

Once our roads are full of cars attracting 'low' VED £ they will need to find a way to tax them off the road next.

 

[tonysmb]

It's extra air drag as well as friction.

 

[st13phil]

If you buy a car used...do you check it has the wheels it left the factory with?

No, but there is well-established precedent that a purchaser may not be reasonably expected to have sufficient knowledge or expertise to identify all modifications carried out by a previous owner and therefore the onus on them to declare as part of the insurance contract is lower.

If, however, I enter into a contract for insurance that states (as all do) that I must declare modifications to the standard vehicle specification then should I subsequently make a modification and not inform the insurer, I would be in breach of that contract.

 

[Petrol Pete]

It's extra air drag as well as friction.

Yeah , that too . F1 cars would be way faster if their wheels were enclosed...but they wouldn't be F1 cars anymore .

 

[190]

Rolling resistance due to width.

This together with extra aerodynamic drag could well be the reason. I know that my car is 1 gram inside it's road tax band and 10mm wider tyres on the same wheel size pushes it up to the next band.

While in practice you would get away with replacing wheels, I suspect anything that changes a cars certified emissions would be illegal.

 

[markjay]

..While in practice you would get away with replacing wheels, I suspect anything that changes a cars certified emissions would be illegal.

I don't know that that's true.... fitting roof racks or rear bike rack (or even mud flaps or side windows wind deflectors) could increase the car's emissions, but I doubt that these would make it illegal.

 

[Petrol Pete]

^^^ like a bloke near where I live . Mazda MX5 phat wheels , front splitter dragging on the ground and a rear wing that would not look out of place on Cessena 172.
He has probably taken 20mph off his top speed and added 5mpg . He should be made to pay more tax because people have to look at the thing !

 

[Petrol Pete]

Changing a cars emission rating is illegal...it's called an MOT , if your car does not pass the emissions 'window' it is classed in , it fails and can not legally be driven on UK roads.

The MOT is static so takes no account of changes in drag coefficient which might push a vehicles emissions up. It's a compromise. I think all manufacturers take into account the weight and drag of all the factory options they offer , roof boxes/rails ,light bars etc.

 

[markjay]

Changing a cars emission rating is illegal...it's called an MOT , if your car does not pass the emissions 'window' it is classed in , it fails and can not legally be driven on UK roads.

The MOT is static so takes no account of changes in drag coefficient which might push a vehicles emissions up. It's a compromise. I think all manufacturers take into account the weight and drag of all the factory options they offer , roof boxes/rails ,light bars etc.

The emissions test for initial certification is different to the MOT emissions test.

Also, my understanding is that the classification test is for the class, but not every individual car is being tested?

 

[renault12ts]

No, but there is well-established precedent that a purchaser may not be reasonably expected to have sufficient knowledge or expertise to identify all modifications carried out by a previous owner and therefore the onus on them to declare as part of the insurance contract is lower.

If, however, I enter into a contract for insurance that states (as all do) that I must declare modifications to the standard vehicle specification then should I subsequently make a modification and not inform the insurer, I would be in breach of that contract.

True. But my point is that when buying a car you likely will not know. So, the risk seems very slight if you change the wheels...unless they are obviously not OEM.

 

[tonysmb]

This together with extra aerodynamic drag could well be the reason. I know that my car is 1 gram inside it's road tax band and 10mm wider tyres on the same wheel size pushes it up to the next band.

While in practice you would get away with replacing wheels, I suspect anything that changes a cars certified emissions would be illegal.

No, it isn't, it's simply a means of certifying the car at build / initial certifcation. Where would they draw the line, mud flaps have the same effect as would anything that adds weight/drag, ie purchasing/carrying a spare wheel if not originally supplied (or carryjng a full complement of 'amply proportioned passengers on every trip). Of course, as with most EU/Govt regns it always seems a good idea when discussed in focus groups but never quite has the intended consequences.

 

[BTB 500]

Where would they draw the line, mud flaps have the same effect as would anything that adds weight/drag, ie purchasing/carrying a spare wheel if not originally supplied (or carryjng a full complement of 'amply proportioned passengers on every trip).

Yep. Fitting a different brand or even model of tyre will change the rolling resistance, as will varying the tyre pressure.

 

[DSM10000]

guys hi, new here, quick question since all posts above from 2015... I plan to buy diesel 2 liter c class, lets say for example c250d 2017 model amg line trim.. what would be the difference of tax between 17" wheels compared to 19" wheels or even 20! if i retro fit later.?? thanks alot

As already stated in this thread.

The RFL is determined for a vehicle as it is specified at manufacture, There is no retrospective change in charges if you modify the vehicle and those modifications alter the CO Value

 

[Spider10]

Yes, you should inform your insurer, and it may affect your premium (though, as said, it won't affect the VED).

You don't have to inform insurance as the car had alloy wheels from factory doesn't matter what size

 

[Spider10]

If its emissions ( im just putting this out there) how come my jag xfs is £225 tax and the range rover is £585 exactly the same engine ?