Avon AM26's. Is the cracking issue over

[Guest]

I'm really starting to think the cold weather has something to do with it.

Pictures soon.....

I was thinking the same thing about the cold weather having something to do with it. I'm in Florida, no cracks, two bikes, two sets of Avon's. I was thinking that during the cold winter months the pressure on the tires will be reduced dramatically if not kept up, then when you put increase the air to go riding in the warmer months it stretches that rubber.
The only problem with this train of thought is why then don't they crack when you put air in them when they're new? Is it because they're older now, lost some elasticity?
I don't put a whole lot of air in mine, actually the bike manufacturers recommended pressure works very well for me.

This is my oldest Roadrider, manufacture date of 2508, (getting long on the tooth), stills has good tread, no cracking anywhere. Even though it about 5 years old, it's gonna go the distance.

 

[posplayr]

I had cracked tires sitting in my garage in Santa Barbara, temps got as low as mid 50's

 

[bonanzadave]

Dave,
I'm sorry you are having problems with the tire again.
I checked with our Returns on this and we haven't had any similar issues logged in.
Please return this back to us for Warranty Evaluation like before.
Thank you,
Ron

Customer Service
Dennis Kirk, Inc.

(800) 328-9280 ext. 2208
(320) 358-4791 ext. 2208




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[FONT=&quot]Dave, do you still have the old tire. Could you advise what the date code is on that tire and the new one that is now cracking and also the size of the tire. It looks like a Venom and I can see what looks like 130/90…[/FONT]


Best regards,

[FONT=&quot]Sukoshi Fahey (Ms.)[/FONT]


[FONT=&quot]Avon Motorcycle Tyres North America[/FONT]
[FONT=&quot]4600 Prosper Dr. Stow, OH 44224[/FONT]
[FONT=&quot]800-624-7470 x 3135 www.avonmoto.com


*********************************************************************************************************************

[/FONT]
Sukoshi,


Both tires are/were Road Riders. 130/90-17


The code on the new tire is 2910. I don't have the old one. Its code was 3209. I sent it back to the vendor (Dennis Kirk) for evaluation. They deemed it defective and sent me a new one. Strange thing is I have a 100/90-19 Road Rider, date code 0510, on the front that looks perfect. ????



Regards, Dave[FONT=&quot]
[/FONT]

 

[Guest]

There is a design or manufacturing defect. To determine the nature of the defect or defects, tires must be carefully dissected, measured, and chemically analyzed. The defect might be functional or merely cosmetic.

If the defect is functional, it might affect safety. Without knowing the exact nature of the defect, and without functional tests such as high speed wheel tests, it is impossible to say.

 

[bonanzadave]

[FONT=&quot]Weird, I checked and the return rate on this size is point .1%. Tire definitely needs to be replaced. Let me check our stock tomorrow for dates for freshest tire.[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]Sukoshi

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[/FONT][FONT=&quot]HI Dave,[/FONT]
[FONT=&quot]I didn?t get a chance to have our guy check stock in the warehouse today. I will have him do it tomorrow for sure. Thanks for your patience.[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]Sukoshi[/FONT]
[FONT=&quot][/FONT]

 

[bonanzadave]

I received this from Avon.....

 

[trevor]

So in other words, if you get any "cracking" in your tires, it's your fault! I hate companies that don't take any responsiablity for their products. And I do have Avon roadriders on both my bikes.

 

[rustybronco]

Those tires have neither fine line cracking of the side walls, nor groove cracking.

 

[bonanzadave]

So in other words, if you get any "cracking" in your tires, it's your fault! I hate companies that don't take any responsiablity for their products. And I do have Avon roadriders on both my bikes.

Not so fast Mr negative......


[FONT=&quot]Okay, I have some with date code of 2011 so I will send out one of those to you. Hopefully there will be no issue with this one. Normally it would need to go back through the dealer but since you have already been inconvenienced once sending it back we will handle directly. Fingers crossed this is a good one. Could you advise an address to ship the tire to and a phone number. Also an address where we can issue a call tag for the old tire.[/FONT]

[FONT=&quot]Sukoshi




[/FONT]Yeah, Im as surprised as you ....[FONT=&quot]
[/FONT]

 

[trevor]

Not so fast Mr negative......


[FONT=&quot]Okay, I have some with date code of 2011 so I will send out one of those to you. Hopefully there will be no issue with this one. Normally it would need to go back through the dealer but since you have already been inconvenienced once sending it back we will handle directly. Fingers crossed this is a good one. Could you advise an address to ship the tire to and a phone number. Also an address where we can issue a call tag for the old tire.[/FONT]

[FONT=&quot]Sukoshi[/FONT]


[FONT=&quot][/FONT]

[FONT=&quot]Yeah, Im as surprised as you....[/FONT]

Good news!! A company doing the right thing.

 

[rustybronco]

I talked to an ex Michelin engineer this morning on this issue. His belief is that this issue is the result of under inflation, putting the sidewall under stress (bulging), and being subjected to ozone gas. He called it polymeric structure cracking.

I'm emailing these pictures to him so he can ask a few of his friends to see what their take on it is.

 

[bonanzadave]

I talked to an ex Michelin engineer this morning on this issue. His belief is that this issue is the result of under inflation, putting the sidewall under stress (bulging), and being subjected to ozone gas. He called it polymeric structure cracking.

I rode on this tire for 5 months (summer 2012) and checked the pressure religiously. 36psi cold and about 38psi hot (+ or - 2 psi). It showed no signs of cracking when I "put her to bed" in Nov. Side stand. Wood floor shed. Not heated. Outside temp ranged between 40f to -15f. Not really a bad winter for MN.

When I looked at the tire in April it was cracked primarily on the bottom and pressure was still at 32psi.

The 3 year old FRONT road rider shows no signs of cracking.

 

[rustybronco]

Dave, I showed him the picture, don't shoot the messenger. I'll update him with the information you just provided.

Also, for your information, tires contain ozone stabilizers that are supposed to leach out of the tire over it's life. Maybe Avon got the mixture wrong?

 

[rustybronco]

Is the cracking completely around the tires circumference? Or just where it rested on the floor?

 

[rustybronco]

Wood floor shed. Not heated. Outside temp ranged between 40f to -15f. Not really a bad winter for MN.

When I looked at the tire in April it was cracked primarily on the bottom and pressure was still at 32psi.

A tires pressure will rise and fall with temperature. When the bike was put away, the air temp was 'X1'. When it was rechecked in the spring the temp was 'X2'. What did the outside temp do between X1 and X2? On average tires loose 1 lb air pressure for every 10 degree change.

Was the bike stored near a source of ozone? If so which end was closest to that source?

What I'm getting at is, there are a lots of factors to consider other than just the tires composition and construction.

 

[Guest]

Antiozonants and antioxidants are both mixed into sidwall rubber compounds. They are dissolved in oil first, because the oil can slowly migrate through the rubber. Surface oil gradually gets wiped away, and is replenished by migration from the interior. The compounds mostly retain their protective power until exposed to ozone or oxygen.

Ozone and oxygen almost certainly have nothing to do with it. Few cars or bikes are stored in areas with high concentrations of either gas. If they did, lots of other tires would be having sidewall cracks. Heck, I've had a temporary spare in my shed for the better part of 30 years. It still has air in it, and no sidewall cracks.

Effect of cold storage on tire aire pressure should be small. The ideal gas law is pretty accurate for the pressure-temperature realtionship. Nerdly calculations are inset.

Pressue x Volume = (number of gas molecules) x Temperature x (R, the ideal gas constant)

or PV = nRT

Volume, number of molecultes and R are essentially constant, so the equation reduces to

P = kT

so, P goes up and down with temperature. Absolute temperature.

Absolute zero is -273C. 30C is a good summer temperature. The coldest winters rarely drop below -40F which is very close to -40C. So the absolute temperatures are 0K, about 233K for very cold winter, and 303K for normal summer.

Pressure drops in proportion to temperature, so the pressure in the tire will drop by a factor of (303C-233C)/303C. = 23%.

23% x 36 psi = 8 psi
​

So the lowest pressure in the tire would be about 28 psi if the tire were cooled to about -40F.

That isn't the reason that the tires are cracking.

Something in the design or manufacture of the tires is bad. I would put my money on design. If I were assigned the job of figuring it out for Avon, I would start by looking at the "glass transition temperatures" of the various compounds. The basic course on rubber chemistry doesn't cover it.

 

[Guest]

This issue has been discussed on this & other boards for a couple years now. AFAIK, Avon still refuses to acknowledge the problem, let alone take action to address it. My rear RR (yes, also cracked) is due for replacement....I'll probably be shopping elsewhere.

 

[bonanzadave]

Is the cracking completely around the tires circumference? Or just where it rested on the floor?

It is all the way around. Both sides. Yes, primarily on the left (chain) side on the bottom. The front is crack free.

Was the bike stored near a source of ozone? If so which end was closest to that source?

Ozone is produced:
- chemically: by white blood cells, by roots of marigolds, and by reactions involving phosphorous (among others).
- by UV light: light with wavelength shorter than 215 nm can break apart an oxygen molecule. Some of this singlet oxygen can join with O2 to form (eventually) ozone (O3).
- by electrical discharge (corona): electrons lauched across a gas (and sometimes water) that contains oxygen will do much the same thing as the UV light.
In industry, it is most common for ozone to be intentionally produced by the corona method in gas that may or may not be pressurized to 1 atmosphere.

Im gonna go with No on that one....

 

[bonanzadave]

Got the new (from the factory) Road Rider today. It came from Micky Thompson Tires in Stow, OH. Date code 2011 so its a couple years old.

I was surprised by how flat the old one was with just a season and a half of riding. Measured about 1/8" less tread depth than the new one. probably less than 2k miles.