205/50/16 or 205/45/16?

Wed Apr 22, 2015 3:59 pm

My touring is currently running 205/50/16s. Wheels are 16x7, but will 205/45 be too small? I will be replacing all 4 tyres.
I'm not sure which will be closest to the standard 205/55/15 and for some reason the online size calculators won't work on my phone.

Another thing to consider is I also have some 16x8 wheels that I'll eventually be using and would like to swap the tyres over to these.

Cheers

Wed Apr 22, 2015 10:08 pm

The closest to standard 205/55 R15 on a 16"rim is 205/50 R16

Wed Apr 22, 2015 10:19 pm

205/50 R16 will not go on 8j rim.
225/50 R16 will go on 7j & 8j rims

Wed Apr 22, 2015 11:50 pm

You'll need 225/45/16 for the same rolling distance, if you go that size on the 8j rim.

Thu Apr 23, 2015 8:28 am

i have 8j rims from a 7 series on my 318 is and they are fitted with 205/50R16 tyres, there's a little bit of stretch but they do fit

Thu Apr 23, 2015 9:03 am

WEEMANDANBRITTON wrote:i have 8j rims from a 7 series on my 318 is and they are fitted with 205/50R16 tyres, there's a little bit of stretch but they do fit

Depends what you mean by 'fit', and whether you're concerned about running with invalid insurance or not.

Thu Apr 23, 2015 6:31 pm

Rav335uk wrote:You'll need 225/45/16 for the same rolling distance, if you go that size on the 8j rim.

Is the wrong answer.
225/50 R16 is near as damn-it the same circumference as your original 205/55 R15.
Whether on 7j or 8j makes no difference to the circumference.
Don't even think about this "stretching" business.

Thu Apr 23, 2015 11:18 pm

minesapint wrote:
Rav335uk wrote:You'll need 225/45/16 for the same rolling distance, if you go that size on the 8j rim.
Is the wrong answer.
225/50 R16 is near as damn-it the same circumference as your original 205/55 R15.
Whether on 7j or 8j makes no difference to the circumference.
Don't even think about this "stretching" business.

nope 225/50/16 is not correct at all its 4% out, 205/50/16 is the closest 16" 205 width to 205/55/15, 225/45/16 is also "equivalent" both are less than 1% different

Thu Apr 23, 2015 11:42 pm

Easy enough to calculate!
Take 205/55R15 : 15" = 381mm, tyre width is 205mm, with a sidewall height of 0.55 of that = 112.8mm. Total tyre diameter = 381mm + (2 x 112.8mm) = 607mm

16" = 406mm, so the diameter of 225/45R16 = 406 + (2 x 0.45 x 225) = 609mm
Diameter of 225/50R16 = 406 + (2 x 0.50 x 225) = 631mm

Fri Apr 24, 2015 12:47 am

reggid wrote:
minesapint wrote:
Rav335uk wrote:You'll need 225/45/16 for the same rolling distance, if you go that size on the 8j rim.
Is the wrong answer.
225/50 R16 is near as damn-it the same circumference as your original 205/55 R15.
Whether on 7j or 8j makes no difference to the circumference.
Don't even think about this "stretching" business.
nope 225/50/16 is not correct at all its 4% out, 205/50/16 is the closest 16" 205 width to 205/55/15, 225/45/16 is also "equivalent" both are less than 1% different

Thank You.

Fri Apr 24, 2015 7:36 pm

Rav335uk wrote:
reggid wrote:
minesapint wrote: Is the wrong answer.
225/50 R16 is near as damn-it the same circumference as your original 205/55 R15.
Whether on 7j or 8j makes no difference to the circumference.
Don't even think about this "stretching" business.
nope 225/50/16 is not correct at all its 4% out, 205/50/16 is the closest 16" 205 width to 205/55/15, 225/45/16 is also "equivalent" both are less than 1% different
Thank You.

Sorry Raj, I'm wrong. You're correct 225/45 R16 for the 8j rim & 205/50 R16 for the 7j

Sat Apr 25, 2015 10:09 pm

minesapint wrote:
Rav335uk wrote:
reggid wrote: nope 225/50/16 is not correct at all its 4% out, 205/50/16 is the closest 16" 205 width to 205/55/15, 225/45/16 is also "equivalent" both are less than 1% different
Thank You.
Sorry Raj, I'm wrong. You're correct 225/45 R16 for the 8j rim & 205/50 R16 for the 7j

No probs, and it's Rav btw.