Tire size alternatives?

[A1_Angelo]

I currently have an Audi A4 avant B7 2.7 Sline TDV. It’s running 235/40zr18 tyres. I was wondering if it would support 235/50zr18? Or even 55? 
thanks

[Magnet]

Hello Angelo - from the Homeland.

Can we take it this proposed change to a higher profile tyre is influenced by wishing for a less harsh ride than you had with the current 40 profile tyres? 
Or is it perhaps something to do with pricing? 
If ride quality, that’s understandable, but before simply considering the implications of increasing the profile, you might need to  check if the estate tyres you have are XL ( I would have thought they were) and if so, they are going to be inherently stiffer than non XL, and will add further to the harsher ride. If you are indeed carrying fairly significant loads, then you will need to stick with them being XL - if not then perhaps worth considering non XL - ? 
Another point:- are your tyres run-flat? If so, these will again be less pliable, and that equals harsher ride. 
To try to answer your question about increasing from 40 to 50 profiles and keeping the same wheels (diameter) - you are increasing the ‘height’ of the tyre by 10% of the width = 23.5 mm, so the actual diameter of wheel and 50 profile tyre will be increased by 23.5mm X 2 = near to 2 inches. 
This will be significant in its affect on gearing and speedometer reading etc. 
Perhaps you can fill in the detail for us Angelo. 
Kind regards,

Gareth. 
 

[A1_Angelo]

Hi there Gareth,

 I would like a higher profile because it would have a better ride, and am I right in thinking the higher profile would suffer less impact from pot holes? 
Yes the tyres are currently XL

Thanks, 

Angelo

[Magnet]

Many thanks Angelo,

I just wonder if we can be excused for thinking manufacturers think all drivers go around corners on two wheels, so need super low profile tyres that don’t flex too much!  I also wonder why Dunlop developed the inflatable tyre when we are going back towards a similar effect to that of the solid tyre.

Yes, you are right that high profile tyres will result in a softer ride, but I think you will find that low profile tyres are generally accompanied by harder sports suspension - so double whammy. 
Personally, I would not fit 50 profile tyres, since the diameter difference will not be insignificant. If you want to fit higher profile tyres, you might have to look at 17 inch wheels, but the suspension set up may still counter that benefit.

Are then any other owners on here who might be able to offer ‘real time’ experience with this?

Kind regards,
Gareth.