Choosing Motorcycle Tires Requires Understanding Their Numbering Through 3 Different Systems

chpChoosing the wrong tire can lead to tire failure or worse…Replacing your tires just requires to copy down the numbering of your current tires. Problems may arise, and it happens more often that you can think, when upgrading to a new brand or size. First things to do is to match your tires to the speed and load ratings. For example, no racing tires on a cruiser and tires adapted to the weight of your motorcycle. There are 4 main motorcycle tire designations (cruising, sport, off-road and racing) For each designation, you need to understand and how to convert 3 different measuring systems used by tire manufacturers, inch/metric/alphanumeric..

The Inch Measuring System. Used for stock and very basic tire sizes, the inch system of motorcycle tire numbering does not see common use. The Metric Measuring System. The most common of the tire size designations, known as the metric measurement, begins with the section width. The inch system is akin to the car tire measurement system..The Alphanumeric Measurement System. Invented by the British and largely phased out by metric tire numbers. Alphanumeric codes are uncommon on today’s tires.

Below, I published tables giving the tire size, speed and load rating conversions across all 3 numbering systems.


14 Responses to “Choosing Motorcycle Tires Requires Understanding Their Numbering Through 3 Different Systems”

  1. 1 Steve Carr Dec 28th, 2013 at 11:38 am

    great info for everyone to have, no matter how much motorcycle experience you may have.

    Thanks Cyril

    Steve Carr

  2. 2 D. Martinez Dec 28th, 2013 at 11:49 am

    I must say, I learned a lot! Thanks.

  3. 3 Shifter Dec 28th, 2013 at 11:50 am

    Very educative. Most mechanics I talked to are quite ignorant about tires…

  4. 4 Bruce Dec 28th, 2013 at 11:53 am

    What about many custom builders mixing tires incompatible with each other, just for looks!

  5. 5 James just another Crazy Kiwi Dec 28th, 2013 at 2:04 pm

    I am going to print it off and take it into one of the local shops.

    I don’t have an HD dealer within 2 hours of where I live so I just use a local Motorcycle Outlet for tires.

    The front tire on the Fat Bob is down so a few days before Xmas I write down the numbers of the front tire and take it into the shop. I do not run the Russian tractor tires HD put on them from new, they aquaplane and are scary in the wet .
    Run a Cobra on the rear and a Venom on the front.

    The Avon site is very helpful when it comes to tire selection.

    I got told by the shop that there is no such tire, I thought well I must have got it wrong.
    Went home and checked it , and I was right.

    Gave up as do not ride much over the Xmas break. Too many Chinese tourists mixed with Fathers that are stressed and hung-over. Driving while the Wife screams at him and the kids either want to fight, urinate or be sick often at the same time. It’s like Russian Roulette with 5 chambers loaded.

    So no tire

  6. 6 Steven M. Sweat Dec 29th, 2013 at 12:10 am

    Great information about the basic types and sizes of tires. Improper tires for the type of bike, weight (including the weight of the rider) can lead to handling problems which, in turn, cause accidents. Thanks for sharing this!

  7. 7 Terence Tory Dec 29th, 2013 at 12:35 pm

    I believe the U.K. Avon Tyres site is the only accurate online listing of M/C tires actual measured widths.

    Most other tire manufacturers only list the estimated width and the aspect ratio.The real measured width can vary between brands even with the same width/ratio.

  8. 8 Zipper Dec 29th, 2013 at 8:00 pm

    I was always concerned about running different types of tires front and rear. Recently I landed up with a few different brands and tread patterns. Fortunately the tires met the factory specks for size and load but had different tread patterns and some bias and other radials.” But anyway” I mounted them up and had very good results with mixing and matching, the best getting rid of the Dunlop on the front of my Sportster replacing it with a Avon tire, what a difference. I did not change tire specs recommended by the bike manufacturer but ran aprox . 40 psi regardless of the book. ..Z

  9. 9 Terence Tory Dec 29th, 2013 at 10:55 pm

    Zipper,if you need to go to such an extreme tire pressure on the front wheel the bike setup must have major issues.Did you try a pressure on the low end of the spectrum?

    Be careful,at 50psi TL MC tires can fly off the rim.I saw a guy do it once.From Mr.Cool,to freaking out like a fool,to Fonzie cool in two minutes.

  10. 10 Zipper Dec 30th, 2013 at 9:10 am

    Terence, thank you for the input. 50 psi is really up there. Most of the tires I have pressures in the 40 range stamped on the tire. I built a custom 68 T120R with a inverted Buell front end which bounced so bad the gas would flow out around the gas cap. All the experts told me it was a tire problem. Not, it was a valve problem thus ending up with a pile of new front tires of different brands and tread patterns. I was very concerned about running two totally different tires front and rear. The tires all met factory specs. Now the the T120R handles great and the Sportster improvement is beyond words. The Dunlop on the rear of the Sportster is almost done and will change brands. Needless to say I experimented with many tire pressures and 40 front and rear works best for me. There are some knowledgeable tire people out there but few. Worth seeking them out if you have concerns. ..Z

  11. 11 1550tc@ Dec 30th, 2013 at 4:55 pm

    Tires are the only thing between you and the road so why dick around and bea cheap ass ?? Just makes no sense especially when you only have 2 of them 🙂

  12. 12 Zipper Dec 30th, 2013 at 6:18 pm

    1550, your correct. Tires are everything. I wish I had the cash back I spent experimenting with all the expensive tires I bought trying to fix my front end problem not to mention the cost of mounting and balance. I was surprised how some of the top line tires are literally riding on their reputation. ..Z

  13. 13 nicker Jan 3rd, 2014 at 12:19 am

    Thanks everyone for the info.

    I’ve managed to remain hopelessly ignorant of tires

    One problem i’ve encountered that it seems the coding schemes can’t reconcile is consistency of the same brenad and mark form one batch of tires to another.

    After i found a type of Micheline tire that worked very well for a specific application, when they needed to be replaced i purchased, what i thought was an identical set. They turned out to be quite different, specifically in side wall stiffness. Very, very disappointing…….. 🙁


  14. 14 burnout Jan 3rd, 2014 at 6:16 pm

    Preachin to the choir here. Educating riders on the proper tire fitment is a never-ending job. I test different Makes of tires on my own bikes and find that what may work perfectly for me does not please someone else. My basic statement on tires is this: Mileage or comfort, tough to get both. peace

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Cyril Huze