Wheels and tyres

[outsmartsmart]

Upgrading my E class from standard fit 16" alloys and have bought a set of S class 18" wheels. It was a bit of an impulse buy as needed to get in quick to get them at the price I paid whilst only having time for quick mental arithmetic to suss out the diameter.

The current wheels/tyres are 225/55x16 and the S type are 245/45x18 so diameters are around 654mm and 677mm respectively, i.e. the S class wheels are about 23mm bigger diameter with these tyres fitted.

Can anbody see any issues with them fitting my 2004 E class or am I doomed to punt them onwards on eBay before I even try

I was looking to replace the two front tyres on mine anyway and the cost of the new wheels and tyres (Pirelli P-Zero's) isn't much more than four new 16" tyres, hence why I took a chance and bought them

 

[television]

Ideally you would need 245 x 40 that gives a side wall height of 9.8cm with the 245 x 45 you have gone up to 110, so the diameter has increased by 24mm almost 1".

I increased mine by 2cm with no ill effect other than that the car shows that I am doing less miles per gallon, as the car has traveled further than it thought, the speedo has stayed near enough but could be say 1-2 mph fast

 

[outsmartsmart]

Thanks TV. I think I'd come to that conclusion really. Speedo 'error' isn't an issue as i use GPS speed camera detector for 'genuine' cruising speeds (hence I'm the one 'tearing past' the jam-sandwich cop car at 73mph whilst its cruising the inside lane of the motorway at 65mph and everybody jams their breaks on and crawls past at 67mph....

As tyre tread depth is about 8mm when new that is 12mm on diameter alone (assuming worn down to 2mm) anyway was my thinking.

Think these wheels will now make my already fantastic car absolutely perfect and all for a bargain price.

 

[Juddian]

Would be very intersted to hear how much the ride quality is affected by the change.

 

[outsmartsmart]

Will let you know accordingly but am basing this on having a Sports supspended C220 CDi with 17" rims and finding that perfectly acceptable. Given the cosseting ride of the E class already and modern tyre/suspension technology I am not expecting to be visiting any medical practitioners with a bad back!!!

It is partially aesthetic reasons for change (although 16" rims on this don't look as bad as 16" rims on my last CLK cabrio') and I was looking for 17" rims really. Also as I already need two new tyres anyway soon'ish these four wheels and tyres are a bargain really.

 

[television]

The higher side wall will leave the car feeling the same as it was before the change, and this was the case on mine

 

[television]

Thanks TV. I think I'd come to that conclusion really. Speedo 'error' isn't an issue as i use GPS speed camera detector for 'genuine' cruising speeds (hence I'm the one 'tearing past' the jam-sandwich cop car at 73mph whilst its cruising the inside lane of the motorway at 65mph and everybody jams their breaks on and crawls past at 67mph....

As tyre tread depth is about 8mm when new that is 12mm on diameter alone (assuming worn down to 2mm) anyway was my thinking.

Think these wheels will now make my already fantastic car absolutely perfect and all for a bargain price.

Do not forget that you must double that 12mm figure diameter is 24mm bigger

 

[outsmartsmart]

Do not forget that you must double that 12mm figure diameter is 24mm bigger

Er, are you correct on that as I have doubled the 6mm = 12mm?? Why do I then double the 12mm.

C'mon which one of is the dur brain on simple maths here, it may yet be me

 

[television]

Er, are you correct on that as I have doubled the 6mm = 12mm?? Why do I then double the 12mm.

C'mon which one of is the dur brain on simple maths here, it may yet be me

If the side wall has increased by 12mm then the diameter must increase by 24mm

 

[outsmartsmart]

I was on about the tread depth had gone from the wear indicator to a new tyre = 6mm increase in wall height, i.e radius, and therefore x2 for both 'sides' of the wheel, i.e. diameter = 12mm.....................

 

[television]

I was only talking of the difference in size by going to the 245 x 45 that would increase the diameter by24mm over what you have on the car now

 

[outsmartsmart]

We've been at cross purposes Malcolm. Your point is what I recognised in my first post, my point about the 12mm was that is the difference between a new tyre and a legally worn one.

Old Chinese proverb says "no matter how close you put your heads together, you never see it quite the same", think that applies here!!

 

[television]

We've been at cross purposes Malcolm. Your point is what I recognised in my first post, my point about the 12mm was that is the difference between a new tyre and a legally worn one.

Old Chinese proverb says "no matter how close you put your heads together, you never see it quite the same", think that applies here!!

So true, the only thing here is that you cannot use tyres with 6mm worn off for very long, as you only have 0.03 of a mm left before its illegal

 

[outsmartsmart]

On the day of the MOT I'm sure many a car has...........

 

[television]

On the day of the MOT I'm sure many a car has...........

MOT !!!! whats that ?