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Iron Butt
Posts: 802
| I checked my rear Cobra today before going on a ride and it was just barely touching the wear bar. Usually at that point I can get one more 300 mile ride before changing it out. So, I went on my ride and pulled the rear wheel when I got home. Lets just say when a Cobra hits the wear bar don't overthink it and just replace the damn thing. Here's one shot of it: 
Here's the other side: 
Learned my lesson! Marc
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Tourer
Posts: 430
| marc - your subject line is right on. You were lucky - your angels were ridin' with you  |
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Visionary
Posts: 1290
Ruskin, Fl | How many miles do you get on a Cobra? |
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Iron Butt
Posts: 802
| I woke up this morning thinking about this and how I could have let it happen. I've been riding for 50 years and have been mounting and balancing my own tires for as long as I can remember. I've even been manufacturing motorcycle wheel balancers for the last 10 years. What obviously must have happened was that when I checked the tire, which I do by just kneeling down and looking at it, the part of the tire which had the least wear was what was visible and what I based my decision to ride it on. In hindsight it probably would have been prudent to spin the wheel and check it all the way around. I'm sure if I had looked at the other side I would have found it worn into the wear bar and I wouldn't have ridden it. Of course I don't have a centerstand so spinning the tire isn't the most convenient thing to do.
But here's what is bothering me. Why is the wear on one side of the tire so dramatically more than the other side? When I think about all the tires I've changed including the pile of used ones waiting to go to the dump, none of them have uneven wear like this one does. Here's the other anomaly that adds to it, when I mounted this one it took 4 ounces, that's 16 1/4 ounce segments in order to get it balanced. I've never used that much weight to get a wheel balanced. I assumed it must be a problem with the Chinese made wheels Vic uses so I made a mental note to check the bare wheel before installing the next tire. I did that yesterday and the wheel itself is out by exactly 1 ounce including the Doran TPS sensor which accounts for over half of it. Even though it isn't out by all that much, I permanently balanced the bare wheel by epoxying the weights to the inside of the wheel rim. Usually I use the heavy spot on the wheel in order to offset the light spot on the tire but Avon doesn't mark theirs so I can't. I also checked the wheel for runout which looked fine.
When I balanced the new tire last night it took exactly 2 ounces of weight which is 8 1/4 ounce segments. This is still more than I've used with other tires and on a pre-balanced wheel as well. Having said that, it is still less than what I used it total in order to get the old wheel/tire assembly balanced. The next thing to check is the new tire's tread depth which I'll do today before I put any miles on it.
In summary, this problem was caused by my not checking the complete tire surface for wear by relying on only one spot. If I had my wife and luggage aboard and on the interstate in the middle of nowhere it could have been a disaster. Lesson learned. On the other hand, in my mind this brings up some questions regarding the tire that I will bring to Avon's attention.
The tire pictured has 5625 miles on it. I ran it hard without the trunk or passenger at 38 psi. I will run the new one at Avon's recommended 42 psi and see what happens.
Marc |
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Iron Butt
Posts: 741
Central New York | It would appear that AVON does not put a lot of effort into manufacturing control. That is a dramatic rubber thickness difference from one side to the other. There really is no other accounting for such a wear difference from one side to the other. Even if you locked the brakes and skidded all the time, you could not consistently do it on the same side. The tire had to come from the factory that out of whack. |
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Central Wisconsin | Sounds like you do a GREAT job of balancing. Are you assuming the Vic wheels are made by the Chinese? Sure sounds like a lot of weight to be attaching to the wheels. I pulled all my weights off and run dyna beads.
Edited by Thomas 2013-02-10 9:11 AM
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Iron Butt
Posts: 802
| Thomas - 2013-02-10 7:09 AM
Sounds like you do a GREAT job of balancing.? Are you assuming the Vic wheels are made by the Chinese?? Sure sounds like a lot of weight to be attaching to the wheels. I pulled all my weights off and run dyna beads.
? The wheels are cast with Made in China on one of the inside webs so no doubt. BTW, even the box that the trans gears come in says China on it. Who knows what percentage of our bikes are sourced from there.
Can you imagine what it would feel like when starting out with a 4 ounce clump of beads sitting in the bottom of the tire? They don't get fully distributed till about 35 mph but it would be a pretty weird ride up till then :-) Of course I doubt anyone actually would put that many beads in their wheel. I've used Ride-On in the past primarily for its sealing properties but even that stuff wouldn't have balanced this situation out.
Marc |
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Iron Butt
Posts: 1066
Peru, IN | They get distributed well enough in the first few feet that you won't feel much. I think 4 oz is about right for a fat tire or car tire (judging from what I've read elsewhere). |
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Iron Butt
Posts: 802
| Monkeyman - 2013-02-10 8:21 AM
They get distributed well enough in the first few feet that you won't feel much. I think 4 oz is about right for a fat tire or car tire (judging from what I've read elsewhere).Bead threads are like oil threads, they go on forever so lets not. I've done a lot of tires in my life and I've never used 4 ounces of weight before. Maybe others have, just not me. One ounce more or less is usually about it. I just mentioned the amount of weight required as maybe some clue as to why the tire wore so unevenly. That's all.
Marc |
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Cruiser
Posts: 244
| You never mentioned checking it for out of round, rim or tire. It was on the rear so you wore it round. Sounds like one mite want to stay away from that brand of tire! |
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Iron Butt
Posts: 802
| wingit3611 - 2013-02-10 10:55 AM
You never mentioned checking it for out of round, rim or tire. It was on the rear so you wore it round. Sounds like one mite want to stay away from that brand of tire!I mentioned that I checked the wheel for runout in post 130665. It was fine, less than .010". I just sent Avon an email asking for them to look into this. The tires handle so great that I'm hesitant to give up on them so quick and have to go back to the noisy, slippery E3s.
Marc
Edited by marcparnes 2013-02-10 1:02 PM
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Puddle Jumper
Posts: 10
Sulphur, La | When I had my wing, I was reading about dyna beads. The majority of the wingers recommended 2 ounces in a motorcycle tire and 3 ounces in a car tire. |
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Visionary
Posts: 2027
Brighton, TN | Marc are the tires that good to get only 5600 miles out of them? I ain't looking for car tire longevity but a decent mileage tire would be great. I guess for just commuting the pavement, i might be hard pressed to change a tire every couple months. Do you have tire machines and uf so what kind? Just pondering outloud! As for your question i got nothing!
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Iron Butt
Posts: 802
| pollolittle - 2013-02-10 6:07 PM
Marc are the tires that good to get only 5600 miles out of them? I ain't looking for car tire longevity but a decent mileage tire would be great. I guess for just commuting the pavement, i might be hard pressed to change a tire every couple months. Do you have tire machines and if so what kind? Just pondering outloud! As for your question i got nothing!
5600 miles stinks. That's for sure. They do make the bike handle great and they don't slip around in the wet or roar like the E3s did but that's a fair question. I've got another rear on there now and I want to see how this one does with more air in it before making a final judgement. I just wish there was something else available that handles this well but lasts even 8K miles. I was getting 10K miles out of the Dunlops. I really don't want to go back to E3s so I'm hoping. The money calculates like this: if you figure a rear goes for about $200 and if you get 10K miles per tire it costs you 2 cents per mile. If you only go 6500 miles (which is my Cobra target) the cost goes to 3 cents per mile. That's an extra $100 to go 10K miles on the Cobra vs the E3. I ride the Vision about 1500 miles per month so the extra cost is $15 monthly or one additional tire purchase per year not including long trips.
I have a powered machine that I bought out of China direct. It is the same one a few US distributors are selling under their own brand name. Its a great machine and makes changing the tire effortless. The only real work left is getting the wheel on and off the bike. I have a lift so even that isn't too bad. Here is the machine I have: 
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Central Wisconsin | Marc, After looking over your balancing products there is no doubt you had the wheel and tire balanced. Do you think the grippy Avon tire could have moved on the rim? Maybe the lower tire pressure and/or the mounting lubricant used might have played a factor in the tire possibly moving. Mark your tire on the rim in a couple of places and find out.
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Tourer
Posts: 466
Grand Cane, LA | I think if I would have had to put that much weight to get a tire to balance, I would have unmounted the tire and rotated it about 120 degrees and tried again. I've never had to use more than 3oz. As far as Avon not having a "tire stem mark" which is usually where the tire is lightest I think you might have missed something. I've run Avons before on my last bike and they have always had a mark. 5000 miles out of a rear tire in "not" usual unless you're abusing it or it had a bad compound mix. |
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Iron Butt
Posts: 802
| atvtinker - 2013-02-10 11:36 PM
I think if I would have had to put that much weight to get a tire to balance, I would have unmounted the tire and rotated it about 120 degrees and tried again. I've never had to use more than 3oz. As far as Avon not having a "tire stem mark" which is usually where the tire is lightest I think you might have missed something. I've run Avons before on my last bike and they have always had a mark. 5000 miles out of a rear tire in "not" usual unless you're abusing it or it had a bad compound mix.The rear Cobra I mounted Saturday and the front sitting on the floor in front of me as well as the rear I removed are not marked for the light spot. I also ran Azaros on my Beemers for years and none of them where marked either.
Certainly rotating the tire on the rim might have resulted in using less weight or it might have resulted in using more weight. Not knowing where the light spot on the tire is nor where the heavy spot on the wheel is makes it nothing more than a crap shoot. Its a popular concept that the heavy spot on the wheel is always at the stem location but that is not consistent on cast wheels. On spoke wheel it usually works out but not cast. The heavy spot on a cast wheel can be anywhere. Point in case is the rear I balanced on Saturday. Even equipped with a TPS sensor the heavy spot ended up about 60 degrees away from the stem assembly.
As for the amount of weight that it took, I totally agree. I've never used that much either. 5600 miles seems unusual as well even though I did run it hard and with 4 psi less than what Avon suggested. It will be interesting to see if and how they respond.
BTW, I really appreciate all the feedback from everyone. I'll be sure to update this thread as the mystery unravels.
Marc |
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Tourer
Posts: 466
Grand Cane, LA | I would be curious as to what Avon says about not marking the tire's light spot for balancing. Doesn't make for good quality control if they don't know their tire is symmetrical and not balancible. |
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Cruiser
Posts: 59
Austin Texas Yaaaalll | Hey Marc. Since my Vision has been in the shop for 7 months getting an engine replaced I was forced to go out and buy another bike. I chose a a '12 Moto Guzzi Stelvio NTX while I wait to get the Vision back. A group of us in Austin all share a tire changer (BTW we use your tire balancer) and we do our own tires. We have noticed a dramatic increase in the price of rubber over the last few years with the normal brands Avon, Metzler etc.... So I decided to try and go with the Shinko brand of tire on the NTX. It is a Korean tire that is getting good reviews on ADV rider for longevity and feel on the road. I paid $160.00 for a set. I paid $180.00 for just the Anankee 2 that is on there now, so I am wondering if there is a Korean (not chinese) tire out there that will will work for the Vision. Like you I ride every day and when the Vision went into the shop I had just put on my second set of ME 880 on her. The first set was a real improvement over the Dunlops, especially in the wet. I got 9,000 miles out of that set. The Shinkos for the NTX (another heavy bike in its class) are waiting in my garage to be put on so I don't have first hand experience yet, but I am expecting good things from them due to the reviews on ADV. |
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Iron Butt
Posts: 802
| I've had a couple of phone conversations with Avon as well as multiple emails regarding what caused this tire to wear so unevenly. I had a phone call with Avon again today and she told me that she spoke with the engineer in England and he had no explanation other than it was an anomaly unless I had been doing burnouts or sliding the bike around. She recommended increasing the air pressure so that there was no more than a 10% differential between cold and hot pressure. She also said that when the current one wears out to call and she'll supply a replacement at a discounted price.
So, basically no answer other than they don't know and don't seem too interested to find out. I'll run the one I've got as she suggested and see how it wears and how far it goes and then decide whether to continue using Cobras or not. Kind of disappointing to be honest.
Marc |
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Iron Butt
Posts: 1066
Peru, IN | Not sure how disappointed I'd be if they're gonna discount your next tire. If they discount it enough, I'd be happy. Bummer the tire wore funny but maybe it IS an anomaly. |
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Iron Butt
Posts: 802
| Monkeyman - 2013-02-21 11:56 PM
Not sure how disappointed I'd be if they're gonna discount your next tire. If they discount it enough, I'd be happy. Bummer the tire wore funny but maybe it IS an anomaly.Yep, you're right. I'll keep a close eye on this new one and hopefully it will do better.
Marc |
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Cruiser
Posts: 244
| " "She recommended increasing the air pressure so that there was no more than a 10% differential between cold and hot pressure." "
marcparnes: I found that 10% remark vary interesting. I had heard that many years ago from Dunlop, and a few years ago a Bridgestone guy said thats wrong.
I Guess air pressure could be like an "oil thread". I personally think the 10% fits all the different circumstances. Would like to hear what the air pressure would be from some of the guy's with the TPS. What thier cold tire pressure ends up being? |
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Could Have Been Nasty
