Another Avon Problem

I Killed my Cobra

Duplicate Post.. My Point of View

We had travelled about 120Km to Lancelin a small fishing town North of Perth.
I had set the bike up and wanted to give it some performance tests and it went like a Rocket and Im not exagerating honest.. It was flying.

Saturday evening returning home from a Dinner with Saori, I decided I would put it through to 6k in 1st and 2nd it was awsome.. levelled it out at 140 and cruised.

The rear tyre split and depressurised after about 30 minutes of riding, the first I knew something was wrong was when I felt a very slight wobble in the steering.. I was down the gears like a fidlers elbow and on the brakes the last few meters the bike was a handful to say the least. The rear tyre had split and the steel cords were exposed. It was dark and we where stranded I rang a friend and got a truck organised..

I tell you this story because I believed the Avon to be a good tyre, and I still do but I am convinced it is not rated for the HP we are getting out of the modified R3. Rear Mileage13,384 KMS

The Avon is most likely fine on a Stock Std R3 as was the case before my Mods.
I know a lot of you are Black listing the Avon and rightly so.. but from my point of view I had good performance and mileage with know problems..

I destroyed my rear tyre by increasing the torque and HP at the Back Wheel and in all Honesty I should be fitting a CT to this monster.
I am not kidding we where 2 up and almost airbourne.

The torque to the back wheel must have be hell for the tyre, I dread to think what the distortion rate was.. the rim was trying to spin the tyre on the road but Saori, weight must have held it.

Anyway we where fortunate not to have had a disaster so for me I will derate the power little and make the safe.. not at all interested in a CT.. so Bridgestone exedra maybe if I can get one... If I was going stocker I would fit another Avon Cobra I think, but Im not maybe just fit the stock mufflers and re-tune and tame it down a little, PCv+AT works a treat

Sorry just wanted to have a say guys..if you got this far thanks for reading the post

CanberraR3 said:

Gald you're both OK Dennsell. I had a rear go flat on me when I picked up a dyna bolt; went completely flat in an instant. Bloody scary, so you're lucky you seemed to have a bit of warning. I've had no problem with a couple of Avons but was surprised at how flimsy they are when the tread gets low. It wouldn't take much to rip the guts out of one and I doubt the extra power you have would have been the sole course. There are some extremely powerful Rockets that have run safely on Metz and Avon - Warp's for a start. I do understand your loss of confidence in the Avon after this experience though.

As I've said before, I'm very happy with the Bridgestone Exedra Max I'm running now but I can't comment on whether engine mods make them less safe. Unfortunately there's only 3 bike tyres to choose from - Metz, Avon and B'stone - which is a different profile. If you're up to it you might want to try a car tyre but it's not a direction I'd go.

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Thanks Richard.. could have been nasty but I uprated the bike and I don't feel that was the Avon tyres fault, we just have to be mindful of what we do and consider what that poor back tyre has to contend with... but it was a hell of a ride and we sat on the road side laughing, I am so pleased I made the decision to immidiately pull over a few more seconds and dread to think..
I learned a lot about the R3 performance.. I suppose with a blower you would need a CT.. but just doesn't appeal to me one bit ..

Darkside CT

If I could find a Car Tyre with rounded shoulders I might (Saying loosely) give one a try.

I just aint happy with a square shoulder for cornering and I don't think I ever will be.

Anyone got or know off a CT with a rounded tread profile by any chance ??

A lot to read and think about here, this has particular interest to me as my next tyre purchase was going to be Cobra's.

As I have posted before, I wrote to Avon and Bridgestone about replacements for the Metz. Only Avon recommended their tyres as they had been tested on the Rockets, but I bet that was on a standard bike with standard rear wheel bhp and torque.

Quite a lot of you guy's are getting around 20-25% more than standard, are you not?, I wonder if Avon's recommendation would alter for bikes with the extra.

I think you have made a very good point Dennsell.

Detune your Rocket to match tire performance?!?!? Really? I mean REALLY???

STRIPES said:

Detune your Rocket to match tire performance?!?!? Really? I mean REALLY???

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And who's suggesting that then.

"maybe just fit the stock mufflers and re-tune and tame it down a little, ..."

Sorry if I read something into this.

Dennsell.
I understand what you're saying as to the cause being extra unleashed ponies rather than a manufactures fault but then, if that be the case then the Avon is already beyond it's limit on a stock bike also.

I don't know what you're getting out of your bike HP/Torque wise but it's not too difficult to achieve the 150 mark on a Rocket without spending a lotta dosh.
Would it be safe to say that is about a 20% increase on Factury spec??

My point being that if I was riding a stock bike with an Avon tyre then the bike is already within 20% of it's fail safe point.
You wouldn't remove the front end and replace it with one from a Sprint and expect it to perform the same.

Personally I wouldn't accept anything less than a 50% safety net on a tyres ability. IE: If it wasn't capable of handling 180HP for an hour of full on abuse then I'd be concerned for it's ability to hold up for 10,000Ks of everyday riding.

I'll get off my box now:soapbox:

You have some strong arguments Cobba - you would expect a safety factor greater than 20% on something like a tyre. But the effect of more hp and torque (torque more likely to be the problem that hp) combined with other factors, may just be pushing the tyres over the edge.

My eyes were really opened reading links to other forums in post #27. Its a lot of reading but worth doing. The effects of low pressures, temperatures and high rear wheel loads has a significant effect on the ability of a tyre to perform as designed.

How many on here can honestly say they haven't at least once run their tyres a bit soft, or ignored the fact that the last time they checked tyre pressures was when the ambient temperature was much lower, or put more luggage on the bike than they should - I know I have.

Triumph must have tested the Bridgestone tyre on the R3T and look what still happened. Now Bridgestone will not recommend their tyres on any model Rocket, such is their concern.

As its unlikely that only Avon users are running soft, hot and overloaded tyres, you have to ask why Metz users don't seem to be getting the some issues.

It would be interesting to hear what Metzeler had to say about running much greater hp and torque.

STRIPES said:

Detune your Rocket to match tire performance?!?!? Really? I mean REALLY???

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LOL
Thanks stripes.. wasn't exactly my meaning but when you get your blower on silip a metz on the back and test it for us

Sorry my thinking was regarding safety for another treasure Saori my wife

She loves riding with me and trusts me implicitly sooo my thinking was ... Stay Safe and don't be tempted to do the same thing again..especially at the age of 67.. savvy ?

I love the R3 but I love my Wife More !!!!