Before we can talk about directional arrows you must first understand a bit about tread patterns. There are many different tread patterns but there is one main reason to have any tread and that is to disperse water. (dust, dirt)
A tread pattern can be designed to disperse more water by making it rotate in only one direction. Thus, the need for directional arrows. The arrow tells you which way to mount a tire for maximum water dispersal. Another, less apparent reason for directional arrows is the tread splice.
What is a tread splice? When a tire is manufactured the tread portion of the tire starts out as a long flat strip. This strip is wrapped around the tire and the two ends are cut on an angle so one end overlaps the other rather than having square cut ends.
This overlapping point or splice offers a bigger surface area to bond together, rather than the small surface area provided by square cut ends. (Imagine gluing your fingertips together, as opposed to gluing along the entire length of your fingers laid on top of each other. Like an angled splice, the overlapping fingers result in a much stronger bond).
To further ensure the strength of this bond along the tread splice the directional arrow will show you which way to mount the tire so that when the rider is “on the gas”; the acceleration force on the rear tire is pressing the splice together, rather than peeling it back.
As for braking, 80 % of the braking should take place in the front on most bikes. Therefore, the front tread splice is run in the opposite direction than that of the rear, so when the rider is on the brakes, he’s not peeling the tread splice back.
If you are using a tire that has a directional arrow for rear rotation only and for some reason you want to put it on the front, make sure it is rotating in the opposite direction so you don’t aggravate the tread splice. Avon Tyres.
nice one Cyril – i knew about the directional arrows, but always thought it was about tread dispersion rather than the spliced bond – which was a puzzle to me when running the same Avon Cobra’s on the front and back!
Interesting post. Thanks Cyril.
I must admit I became a mre knowledgable biker with all what I learn daily reading your blog. Great work.
Any opinion about reversing the arrow when running a rear tire on the front? or vice versa. Avon makes some cool old tread patterns and are good tires but they don’t make some of the same sizes for front and rear.
The AV71 Cobra is a universal fitment for 23″ wheels
just me, but I’ve run a few rear tires “backwards” on the fronts and it has been a common practice way before my time. A lot of the old Metric bikes had skinny 17″ tires that looked good as cafe fronts.
Thanks Cyril!!
This information is going to become part of my High School motorcycle course.
Keep the good info coming!!
Mazz.
great artical very intersting and informative. I how ever have been using the avon for years now because they feel better. The stock HD dunlop tire grabs the groves in the highway and throws the bike around a bit. The dunlop seems to follow the grooves. But the avon tires seem to just float over those same grooved highways. I am not sure why that is but I like it and thats why I run avon tires. I may be wrong but it seems to me that the avon does not last as long as the dunlop thou. But I do like the ride better so I will keep buying them.
Thanks Cyril; That’s great info..
Thanks Cyril,
This was one of those things that make you go Mmmmm.
I love Avon tires,
I have used them on every bike I have owned or built (except one) since 1970,
First time user of Avon tires, had them installed on my 1976 CB750 SuperSport, front & rear I’m hooked on them, the best ride and great steering handling It’s had in a very long time. Thanks Avon for a great tire.
You are so wrong about the tread pattern being designed to disperse more water when turning one way than the other. A water droplet on the road doesn’t care which direction a tire’s tread is oriented. In fact, many motorcycle front tires have a tread pattern that appears backwards from a similar tread on the rear tire. Look at the photo of the tires above, for instance.
The fact that a tire does or doesn’t have tread is way more important to that tire’s wet road performance than the orientation of the tread. Tread is on a tire to provide void space and to reduce the size of the contact patches (lugs) in the tread. The smaller the individual contact patches in a tread pattern the shorter the distance water has to go to get out from under them when the tire rolls and presses them onto he road surface. Deeper tread (more void space) is associated with improved resistance to hydroplaning and generally improved wet road traction as is smaller tread pattern componenets, all other things being equal..