Question about tire sizes

[Hef]

I am due for tire replacements and so I checked with a dealer to get prices. He tells me Michelin has a new Motorcycle tire that is the greatest. He says several guys are running them and getting 15-20K on a rear tire. The catch is the sizes are a bit smaller. The front calls for a 150/80/17. The michelin front is a 140/75/17. The rear calls for a 180/70/16. The michelin rear is a 180/65/16. I would like to hear your thoughts on this. I almost never stray from manufacures specs. TIA, Hef

[gordonv]

This will show what the tire size differance will mean in MPH.

You decide if this is right for you.

http://kgm.tiwing.com/calcs/tiresizecalc.htm

[PhredValk]

Front stock
150/80HR-17 120mm

130/90-17 117mm
140/80-17 112mm
140/90-17 126mm
150/70-17 105mm
150/80-17 120mm
160/70-17 112mm

Front tire size will affect your speedo readings. Rear sizes will affect your RPMs at any particular speed (I don't have the same comparison for rears, except for Darkside tires).
Fred.

[Hoser]

I use a 180/65/16 on the rear, I don't notice much difference.  I'm at 65 mph at 3000 mph.  My front is 150/80/17.  These.  Hoser
 

[Denny47]

Have heard much good about the Michelin Commander ll and I have one on my Goldwing. I am liking it on the Wing and it did change my rpm for the better due to it being slightly larger than the OEM size but on the Valk it will increase your rpm a bit since it is a little smaller than the Valk rear. Have talked to several guys running these on other bikes, non Valk, and they are getting better mileage than any other brand, other than a car tire. I will be going to the Austone when my E3 wears out.

[sandy]

I've posted this a few times. I currently have 22K on my rear Avon Cobra. Always keep it at 46PSI.
I'm also a believer that handling was engineered by the factory with a specific tire size and profile. Changing a tire size may or may not be bad for handling. You'd be taking your chances.

[Mallett]

I've posted this a few times. I currently have 22K on my rear Avon Cobra. Always keep it at 46PSI.
I'm also a believer that handling was engineered by the factory with a specific tire size and profile. Changing a tire size may or may not be bad for handling. You'd be taking your chances.

Sandy, don't know how you can ride it with 46PSI....38 is about all I can stand....BTW, I think the factory specs. is 32PSI....

[John Schmidt]

I've posted this a few times. I currently have 22K on my rear Avon Cobra. Always keep it at 46PSI.
I'm also a believer that handling was engineered by the factory with a specific tire size and profile. Changing a tire size may or may not be bad for handling. You'd be taking your chances.

Sandy, don't know how you can ride it with 46PSI....38 is about all I can stand....BTW, I think the factory specs. is 32PSI....

For currently available tires you need to ignore the factory specs, it's been that way almost from the beginning with the Valk. At those low pressures you'll be spending more on new rubber. None of the current tires being run on the Valk will last with low pressure, they all start to cup rather early. When I was still running a bike tire in back, I always ran my tires with 40/42...front/rear. My front Metz now is closing in on 20k, always run 40 psi in it and it's not cupping. The rear has a car tire so the high pressures don't apply.

[Denny47]

Hef, you can figure the tire sizes yourself when you understand the way to do it. For example, oem tire 180/70/16, the 180 is the width of the tire in millimeters. The 70 ( 70 percent) is the ratio distance from the rim to the ground/tread, and the 16 is the rim diameter, measured across the rim on the inside where the tire bead seats. 180mm x .70 = 126mm . A 180/65= 117mm. This would show that the 65 is 9mm shorter than the 70 from the rim to ground. 9mm is just a little over 5/16". Hope I explained this well enough.

[sandy]

I've posted this a few times. I currently have 22K on my rear Avon Cobra. Always keep it at 46PSI.
I'm also a believer that handling was engineered by the factory with a specific tire size and profile. Changing a tire size may or may not be bad for handling. You'd be taking your chances.

Sandy, don't know how you can ride it with 46PSI....38 is about all I can stand....BTW, I think the factory specs. is 32PSI....

As was stated: Ignor the factory tire pressures. The original Dunlops weren't very high quality tires. I've had several sets of Avons and have always run this pressure. I also have Works performance shocks spec'd to my weight. The pic was taken with my last Metzler.

[Hef]

Thanks to everyone. I think I have decided to go with the Dunlop Elite III again even though they are quite a bit higher in price. Hef