Converting tyre sizes.
Submitted: Friday, Oct 28, 2011 at 18:06
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Fab72
Hello All,
My little 4 wheeler (Pajero io - 5 door) has 215 65R 16 tyres fitted at the moment. As soon as these wear out, I'd like to fit something a bit more meaningful.
I understand that it will probably require a rim upgrade to accommodate any significant width increase and I'm mindful of watching out for changes in track, scrubbing of tyres on full lock etc etc.
The only question I have is how do I convert my current tyre size into what is more commonly referred to in the off road circles?
Before I start shopping for 28's, 31's, 33's etc, I'd like to know where I'm at now as a sort of baseline.
Does someone have the answer or is there a basic conversion multiplier to use?
Cheers...Fab.
Reply By: Member - Howard (ACT) - Friday, Oct 28, 2011 at 18:20
Friday, Oct 28, 2011 at 18:20
Hi Fab ,
for a convertion multiplier use 25.4mm = 1 inch
your present tyres are 27"
how did i get that?
easy, 215 65 16 means you have a 215mm wide tyres in 65% aspect ratio on a 16 " rim
65% of 215 is 139.75mm -this is the height of rubber under and above rim so multipy by 2 gives you 279.5mm
then add 16 x25.4for rim which is another 406.4mm (rim diameter in mm)
which gives you a total tyre height of 685.9mm
if you divide 685.9 by 25.4 you get 27"
simple as that
cheers
Howard
AnswerID:
468764
Follow Up By: Fab72 - Friday, Oct 28, 2011 at 18:30
Friday, Oct 28, 2011 at 18:30
Thanks Howard,
Appreciate the fast response. It took me a couple of reads but it all makes sense.
Cheers...Fab.
FollowupID:
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Follow Up By: Member - nick b - Friday, Oct 28, 2011 at 22:05
Friday, Oct 28, 2011 at 22:05
Dont forget legally you may only increase the over all size by 15 mm from std ....
FollowupID:
743085
Reply By: Member - John and Val - Friday, Oct 28, 2011 at 19:53
Friday, Oct 28, 2011 at 19:53
Fab,
Howard is right of course, but in the box beside your post is a link to the ExplorOz tyre size converter! Very useful!
Something to watch if you change rims to get wider - check the offset, i.e. where the mounting plane lies in relation to inside and outside faces of the tyre. There usually isn't much clearance inside, so the offset can be critical.
Cheers
John
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Reply By: Member - Boobook - Saturday, Oct 29, 2011 at 06:18
Saturday, Oct 29, 2011 at 06:18
I always use this site, it is very comprehensive with the details. Width, diameter, etc etc
Tyre size calculator
It also shows if a tyre size is non standard.
AnswerID:
468788
Reply By: Member - Phil G (SA) - Saturday, Oct 29, 2011 at 08:42
Saturday, Oct 29, 2011 at 08:42
Xtrail owners have been through this over many years as 215/65R16 is a common size. Don't worry about measuring your tyres in inches - it is just a simple way of telling people the diameter of your tyres and 27" doesn't sound right!
Can I suggest you have a good look through the many tyre threads on the Australian Xtrail
forum to see what A/T tyre options they use.
The tyre threads are grouped here.
In general, you improve the offroad ability most by increasing diameter, not width. Clearance is the big issue with the smaller 4wds and it is what gets them stuck in my experience. If you increase diameter you also alter gearing and the speedo, so you will notice a drop in power.
AnswerID:
468800