Next Size Down.

[johnlewis1964]

Hi folks what is next tyre size down from
225x45x17
For 17x7.5 wheels many thanks

 

[renault12ts]

215 45 17

 

[rf065]

Not sure why you're asking, but 205/50x17 is the nearest match in rolling circumference.

 

[Gazwould]

But is it , in the real world ?

 

[johnlewis1964]

I just think the sidewall is a bit high on the 225x45 x17 looking a lower profile cheers

 

[Gazwould]

On another car with 7.5 X 17 I run 235 45 , I ideally would not run less on Britain's broken roads .

 

[rf065]

Max tyre width for a 7.5J rim is 235, but you need to check the circumference is within limits if you change the profile.

 

[400ixl]

But is it , in the real world ?

Its mathematics, its a constant in the real world.

225/45/17 = 199.2cm circumference

If you want to go down in size (but up in profile to give the effect of filling the arches more) and giving more comfort and wheel protection then:
215/50/17 = 200.0cm circumference which would mean at a real 70mph the car would read 71.97mph
215/45/17 = 196.3cm circumference which would mean at a real 70mph the car would read 68.58mph

If you want a lower profile then:
235/40/17 = 194.6cm circumference which would mean at a real 70mph the car would read 67.71mph
235/45/17 = 202.0cm circumference which would mean at a real 70mph the car would read 71.42mph

So 235/40/17 would be the next size up in tyre (but down in profile). You would need to check that Mercedes actually fitted this size tyre to your model, otherwise its a non OEM size and a modification to be declared to the insurer.

 

[renault12ts]

I just think the sidewall is a bit high on the 225x45 x17 looking a lower profile cheers

If you want to keep everything correct but have a lower side wall then the only thing you can do is get bigger 18" wheels. The tyre sidewall will be lower.

If you want a lower sidewall for your existing wheels then you will be changing the gearing. Not by much...but it will not be correct.

 

[flowrider]

I just think the sidewall is a bit high on the 225x45 x17 looking a lower profile cheers

In that case you will need to increase wheel size.

 

[Stratman]

Its mathematics, its a constant in the real world.

225/45/17 = 199.2cm circumference

If you want to go down in size (but up in profile to give the effect of filling the arches more) and giving more comfort and wheel protection then:
215/50/17 = 200.0cm circumference which would mean at a real 70mph the car would read 71.97mph
215/45/17 = 196.3cm circumference which would mean at a real 70mph the car would read 68.58mph

If you want a lower profile then:
235/40/17 = 194.6cm circumference which would mean at a real 70mph the car would read 67.71mph
235/45/17 = 202.0cm circumference which would mean at a real 70mph the car would read 71.42mph

So 235/40/17 would be the next size up in tyre (but down in profile). You would need to check that Mercedes actually fitted this size tyre to your model, otherwise its a non OEM size and a modification to be declared to the insurer.

Something to bear in mind is that's it's illegal for a speedometer to under read. All tolerance in the regulations is on the high side.

 

[Deleted member 149005]

Is the OP looking for a smaller contact patch or a smaller sidewall?

Put another way, what is the goal?visual aesthetics or a different ride / handling balance?

As others have posted, a smaller sidewall may require a larger wheel to maintain the rolling circumference, which is a bit self defeating.

 

[flowrider]

Is the OP looking for a smaller contact patch or a smaller sidewall?

Put another way, what is the goal?visual aesthetics or a different ride / handling balance?

As others have posted, a smaller sidewall may require a larger wheel to maintain the rolling circumference, which is a bit self defeating.

See post #5

 

[johnlewis1964]

Thanks you all very much.

 

[Gazwould]

Its mathematics, its a constant in the real world.

225/45/17 = 199.2cm circumference

If you want to go down in size (but up in profile to give the effect of filling the arches more) and giving more comfort and wheel protection then:
215/50/17 = 200.0cm circumference which would mean at a real 70mph the car would read 71.97mph
215/45/17 = 196.3cm circumference which would mean at a real 70mph the car would read 68.58mph

If you want a lower profile then:
235/40/17 = 194.6cm circumference which would mean at a real 70mph the car would read 67.71mph
235/45/17 = 202.0cm circumference which would mean at a real 70mph the car would read 71.42mph

So 235/40/17 would be the next size up in tyre (but down in profile). You would need to check that Mercedes actually fitted this size tyre to your model, otherwise its a non OEM size and a modification to be declared to the insurer.

Can't apply it to tyres as they don't make to sizes .

What's the difference between 205 55 16 and 235 45 17 ?