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

Posted: Wed Apr 22, 2015 3:59 pm
by jmc330i
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

Re: 205/50/16 or 205/45/16?

Posted: Wed Apr 22, 2015 10:08 pm
by minesapint
The closest to standard 205/55 R15 on a 16"rim is 205/50 R16

Re: 205/50/16 or 205/45/16?

Posted: Wed Apr 22, 2015 10:19 pm
by minesapint
205/50 R16 will not go on 8j rim.
225/50 R16 will go on 7j & 8j rims

Re: 205/50/16 or 205/45/16?

Posted: Wed Apr 22, 2015 11:50 pm
by Rav335uk
You'll need 225/45/16 for the same rolling distance, if you go that size on the 8j rim.

Re: 205/50/16 or 205/45/16?

Posted: Thu Apr 23, 2015 8:28 am
by WEEMANDANBRITTON
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

Re: 205/50/16 or 205/45/16?

Posted: Thu Apr 23, 2015 9:03 am
by Brianmoooore
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.

Re: 205/50/16 or 205/45/16?

Posted: Thu Apr 23, 2015 6:31 pm
by minesapint
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.

Re: 205/50/16 or 205/45/16?

Posted: Thu Apr 23, 2015 11:18 pm
by reggid
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

Re: 205/50/16 or 205/45/16?

Posted: Thu Apr 23, 2015 11:42 pm
by Brianmoooore
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

Re: 205/50/16 or 205/45/16?

Posted: Fri Apr 24, 2015 12:47 am
by Rav335uk
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. :P

Re: 205/50/16 or 205/45/16?

Posted: Fri Apr 24, 2015 7:36 pm
by minesapint
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. :P
Sorry Raj, I'm wrong. You're correct 225/45 R16 for the 8j rim & 205/50 R16 for the 7j

Re: 205/50/16 or 205/45/16?

Posted: Sat Apr 25, 2015 10:09 pm
by Rav335uk
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. :P
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.