Tyre direction - what's it mean?

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old man emu
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Tyre direction - what's it mean?

#1

Post by old man emu »

Time to replace my front tyre on the Walla.

I would like to fit an Avon Safety Mileage Mk II tyre, but it is marked as a "rear" tyre. Weren't the original tyres on the WLA the same?

I was wondering if, since I hardly ever travel faster then 80 KpH (50 mph) if it would be bad to fit one of these to the front.
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Re: Tyre direction - what's it mean?

#2

Post by Pascal »

No.


'Front' or 'Rear' has something to do with load; a bike is (and may be) heavier in the rear than in the front.
kitabel
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Re: Tyre direction - what's it mean?

#3

Post by kitabel »

The rear tire, as seen front the left, is torqued CCW by the chain.
The front tire is torqued CW by the front brake.
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Re: Tyre direction - what's it mean?

#4

Post by RUBONE »

Many modern tires have "directional" patterns in the tread and are designed to run best in that direction. Things like sipes for moisture deflection, etc are oriented for maximum effect. However they can be run either direction and fronts are usually mounted backwards on bikes that use interchangeable tires. Plus on old iron they do not see anything close to their design limits.
old man emu
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Re: Tyre direction - what's it mean?

#5

Post by old man emu »

kitabel wrote: Thu Aug 19, 2021 6:47 pmThe rear tire, as seen front the left, is torqued CCW by the chain. The front tire is torqued CW by the front brake.
I can see that what you say is true in relation to the application of torque forces to the front tyre. but one could say that braking only occurs during, say, 5% of the tyre's usage. The other 95% of the time it is being subjected to torque forces acting in an anti-clockwise direction in response to the transmission of force through the frame from the chain acting on the rear tyre. Also, when the rear brake is applied, the rear tyre is subjected to torque forces in the anti-clockwise direction.

RUBONE:
Your reply seems to be "little this way, and a little that way".
Do you mean that if a tyre, said to be for the rear wheel, has an arrow on it pointing in the clockwise direction, then if you wanted to put it on the front wheel, you would have the arrow pointing in the anti-clockwise direction?

The tyre I am looking at has a "service index" of 64S for an 18" tyre and 69H for the 16" tyre. (Someone put a 16" wheel on the front of my bike.) I believe that the "S" means the tyre is rated to a bit over 100 mph and "H" is for 130 mph. The maximum load for tyres in the 64# to 69# range is about 600 lbs.

With that, is the opinion going to be that it is OK to fit this "rear" tyre to the front, as long as the roll direction was reversed?
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Re: Tyre direction - what's it mean?

#6

Post by flatboy1950 »

The directional tyres are for modern bikes. The rear tyre is designed to handle 200 + horsepower .... you may have 20 hp if you are lucky !!
The front tyre is able to take the stopping power of twin Brembo discs ; you have NO front brake .... almost !!
So it does not matter which way these tyres are fitted !!!!
Flatboy.
old man emu
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Re: Tyre direction - what's it mean?

#7

Post by old man emu »

flatboy1950 wrote: Sun Aug 22, 2021 8:01 amThe directional tyres are for modern bikes. So it does not matter which way these tyres are fitted !!!! Flatboy.
That was my hope. The same tyres front and rear will bake the bike look better.
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