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Offline cecilt

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Tyre tread pattern
« on: November 26, 2014, 09:37:21 am »
This has been bothering me for some time. Most road-tyre tread patterns roughly have a "V" configuration, and for some fitted tyres, the point of the V touches the road surface first, presumably to disperse any water laterally. However, I notice many front tyres where if seen from the front, the V shape is inverted (as also seen in pictures on this forum). Surely when going forward, this would drive any water from the road surface to the mid-line of the tyre, and thereby reduce traction? Are these tyres fitted incorrectly? :187: And why would the rear tyre pattern configuration differ from the front? :435:
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Re: Tyre tread pattern
« Reply #1 on: November 26, 2014, 01:26:38 pm »
What you've seen is correct !  Essentially an inverted V design helps to reduce wear (namely ’stepped-wear’ and cupping) on the front tyre when braking. Although it could also be argued that cuppimg only occurs if the front suspension is incorrectly set, the idea of a inverted V design has been found to increase stopping distances especially when the tyre progresses through its wear cycle.

Whatever you do ensure the tyre is fitted according to manufacturers instructions, and don't turn tyres "around" just to achieve the above  :002:

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Offline azgman

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Re: Tyre tread pattern
« Reply #2 on: November 26, 2014, 03:59:26 pm »
I always thought it is because the front tire is being pushed while the rear tire is pulling the bike forward.

Anyone here work in the tire industry?   :187:
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Offline Coconut

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Re: Tyre tread pattern
« Reply #3 on: November 26, 2014, 06:21:12 pm »
A tyre / tire that is designed to fitted only"one way round" is known as "Directional",
and will be marked on the sidewall, usually with an arrow, to indicate the direction of travel.

Such tyres / tires should NEVER be fitted the "wrong way round".


Offline Old Hand

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Re: Tyre tread pattern
« Reply #4 on: November 26, 2014, 06:49:11 pm »
I, too, questioned the inverted "V" tread pattern on the front tyre which would move water towards the centre of the tyre contact patch. According to what I read, the reason for this tread pattern is to align the tread blocks (of rubber) with the direction of load forces on the front wheel, particularly when cornering.

Having ridden through several hours of rain in temperatures of 8-10 C on Michelin Pilot Road 3s, I can say that the inverted "V" tread pattern, although counter-intuitve, did not adversely affect the performance of the tyres at all. The tyres performed flawlessly and I was able to ride through turns at 120 Km/hr with full confidence - faster than any of the four-wheeld vehicles on that road at the time.
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Offline azgman

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Re: Tyre tread pattern
« Reply #5 on: November 26, 2014, 08:08:54 pm »
Avon tires explanation

And here is the best explanation I could find...

The rear tire needs to shed water mostly when it is accelerating (i.e., speed of rotation is increasing, if we define the direction of rotation for forward motion as positive). For a water droplet in the middle of the tire tread, it will feel the tire accelerating in the forward direction, so the water droplet is 'left behind', and the channels are aimed toward the back of the tire (the direction opposite rotation). On the front tire, the most important time to shed water is under braking - when the tire is being accelerated in the opposite direction. As the tire accelerates backwards (i.e., it goes from 2000 rpm to 1000 rpm - this is the same as accelerating the bike backwards, although we often call this 'deceleration'), a water droplet on the tire wants to continue rotating forward, so the grooves are aimed in the 'forward' direction so that the water will flow out of the groove. From a physics point of view, slowing down a bike with the front tire is equivalent to accelerating it backwards, with the front wheel as the drive wheel. It makes sense that the tires would have grooves in opposite directions - one tire primarily accelerates the bike in the forward direction, the other tire only accelerates the bike in the backwards direction (also known as braking).
« Last Edit: November 26, 2014, 08:24:38 pm by azgman »
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Re: Tyre tread pattern
« Reply #6 on: November 26, 2014, 11:24:24 pm »
Some more info on Avon's website, scroll down to Inverted Front Grooves section, here and here

Offline Saaz

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Re: Tyre tread pattern
« Reply #7 on: November 26, 2014, 11:46:37 pm »
I have used a few of the modern inverted V design tyres, and they sure do work exceptionally well in the wet. I also have experienced torrential rain where I felt safer on the bike than the cars around me, purely because of the way the bike tyres cut through the surface water due how narrow the tyres are relative to most cars.

 



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