The tire that just won't die...

[FrugalNinja250]

Just turned 24,000 miles on my front Kenda K671. It has some cupping and two plug repairs from around the 16k mile point, but still has 1/8" depth in the center groove. Handling-wise it's a little squirrely in the upright position, making it more wind-sensitive than the dry-rotted Dunlop K630 it replaced back in the summer of '09. Once leaned over, though, it grips just fine and I'm fully confident in it for day to day riding. I hate taking off tires with any usable tread left so my brand new K671 is sitting in the closet like it has since last fall.

If you've got a pregen (mine's an '06) that you put a lot of mostly upright miles on I can't recommend these strongly enough. If mine ever dies I'll post back the final mileage...

[Too40gawlf]

I know you must be frugal as your screen name indicates. But when it comes to motorcycle tires, for God's sake dont skimp. From how you describe the tire, its well past its service life. Why take chances when you dont need to?

["A"]

Need to find yourself one of these to scrub the tire back proper:

[jmgrande]

Originally Posted by Too40gawlf

I know you must be frugal as your screen name indicates. But when it comes to motorcycle tires, for God's sake dont skimp. From how you describe the tire, its well past its service life. Why take chances when you dont need to?

Agreed. This sounds extremely dangerous and like a disaster waiting to happen...

I would NOT ride on tired that have plugs in them.

[FrugalNinja250]

Plugs aren't a problem. I did a lot of research and found almost zero occurrences of plug failures. The few I did find seemed to be associated with either improper install or use on tires run a lot harder than these can be on this bike. I wouldn't plug a race tire, or a tire going to the track, or a tire on a much bigger, heavier bike. Front of the Ninja weighs less than I do and my experience has been they work just fine. I'm comfortable with that, and don't feel there's any additional danger or risk to me or bike. I went back and looked at my logs, I actually plugged the tire at 15,525 miles and it now has 24,271 miles. Was two plugs, dang office staple...

[bob706]

Originally Posted by jmgrande

I would NOT ride on tired that have plugs in them.

To a point but certainly not 8K miles. I would say you got your moneys worth and put the new one on.

[oroboros]

So whats the deal with my front tire? Not to hijack your thread Frugal...

I have 3K on my stock tires and the front is worn down to the wear marks. The rear looks fine?

I really do not think that I am doing anything unusual. No doubt I spend a lot of time in the curves but I would imagine that my rear would wear first?

Frugal, I think I would just change it at this point! At least you have a replacement.

[oroboros]

Originally Posted by "A"

Need to find yourself one of these to scrub the tire back proper:

That kinda looks like fun

[bob706]

Originally Posted by oroboros

So whats the deal with my front tire? Not to hijack your thread Fugal...

I have 3K on my stock tires and the front is worn down to the wear marks.

Using more front brake than rear or not inflated properly would be my guess.

[gfloyd2002]

Scalloping on the tire + two plugs + 24k miles = past time to change tires. Happy you got so much use of out it, but the last thing you want is to ride a tire until it fails at speed. Geez man, change the tire already.

[FrugalNinja250]

Originally Posted by gfloyd2002

Scalloping on the tire + two plugs + 24k miles = past time to change tires. Happy you got so much use of out it, but the last thing you want is to ride a tire until it fails at speed. Geez man, change the tire already.

Has anyone actually had a tire fail at speed? Or at all? And if so, what was the failure sequence? Just curious...

I worked for several years for a major tire distributor doing initial failure analysis on customer-returned automotive tires. In my experience, the number one reason for non-impact failure was chronic underinflation, to the tune of 98%. Of those, perhaps 2% were due to a failed repair, more often a patch than a plug. Overall, patch and plug failures represented a minuscule fraction of one percent of all failures, and none of those were catastrophic in the sense that suddenly the patch or plug just blew out or instantaneously lost pressure. They were slow leaks that ultimately led to severe underinflation, causing overheating of the carcass and subsequent interlayer bonding failure. If the tire owner had checked the pressure more often than once every other full moon the failure would have been prevented.

Don't worry, I'll change it before it becomes risky to me or anyone else.

[gfloyd2002]

lol, well if anyone is riding a scalloped tire to 24k miles, I'm really glad it is someone who is worked as an analyst regarding reasons for tire failures. Definately not for someone without detailed tire knowledge.

And thank goodness, no, never had a motorcycle tire fail at speed. Car tires, yes, and that was scary enough. I can guess at failure sequence, though. It would be 1) Driving around with a grin enjoying Ninja; 2) FFFFUUUUUUU!; 3) Who am I and why do I have all these casts?

["A"]

Originally Posted by oroboros

That kinda looks like fun

It is, 270 degree right turns... and most motorcycles can easily out accelerate vehicles merging.. it's a practical way to balance out the cupping on tires and you get to master the right hand turning and merging.

[FrugalNinja250]

Will I have to go to England to smooth out the left side cups?

[bob706]

Originally Posted by FrugalNinja250

Has anyone actually had a tire fail at speed? Or at all? And if so, what was the failure sequence? Just curious...

I worked for several years for a major tire distributor doing initial failure analysis on customer-returned automotive tires. In my experience, the number one reason for non-impact failure was chronic underinflation, to the tune of 98%. Of those, perhaps 2% were due to a failed repair, more often a patch than a plug. Overall, patch and plug failures represented a minuscule fraction of one percent of all failures, and none of those were catastrophic in the sense that suddenly the patch or plug just blew out or instantaneously lost pressure. They were slow leaks that ultimately led to severe underinflation, causing overheating of the carcass and subsequent interlayer bonding failure. If the tire owner had checked the pressure more often than once every other full moon the failure would have been prevented.

Don't worry, I'll change it before it becomes risky to me or anyone else.

Don't quote me but don't a majority of motorcycle tire failures occur when it's on its last 10% of life?

[Too40gawlf]

I'm not an expert by any means. I think modern tires have a lot more capability and longevity that we credit them for. However, when it comes to tires, I prefer to err way on the side of caution. Although in this case, FrugalNinja seems to know what he's talking about.

[FrugalNinja250]

Originally Posted by bob706

Don't quote me but don't a majority of motorcycle tire failures occur when it's on its last 10% of life?

I guess it would depend on the failure. In car tires most catastrophic failures are related to either impact/hazard damage or being run low/near flat. In some environments such as police cars tires are never repaired, only replaced, but the repaired tires get shuffled off to other cars in the city fleet to run out their useful life. I was unable to find an authoritative source for motorcycle tire failures and modes, and dang few anecdotal reports. Typically it was just reports of a front or back tire going flat. The closest I've seen to an actual failure was a friend who ran his Vaulk across the Mojave at 80+ with an underinflated rear tire near the end of its useful service life. At the end of that ride he had cord showing most of the way around. Big, heavy bike, extreme conditions, high speed and low pressure, yeah, he was lucky.

[Jesse8931]

Originally Posted by FrugalNinja250

I guess it would depend on the failure. In car tires most catastrophic failures are related to either impact/hazard damage or being run low/near flat. In some environments such as police cars tires are never repaired, only replaced, but the repaired tires get shuffled off to other cars in the city fleet to run out their useful life. I was unable to find an authoritative source for motorcycle tire failures and modes, and dang few anecdotal reports. Typically it was just reports of a front or back tire going flat. The closest I've seen to an actual failure was a friend who ran his Vaulk across the Mojave at 80+ with an underinflated rear tire near the end of its useful service life. At the end of that ride he had cord showing most of the way around. Big, heavy bike, extreme conditions, high speed and low pressure, yeah, he was lucky.

Not sure about where you live. But here if a police tire is damaged it is cut so it cannot be repaired.

Back in the 90's my grandfather owned a tire scraping company.

And 90 % of accidents caused by tires were people under inflating there tires to get a smother ride causing the rubber to heat up and split.

[Xoulrath]

Frugal, I am glad you have gotten so much use out of that tire. I too am thrifty, and I can appreciate where you are coming from. I am also glad that you have detailed knowledge about tires and their life cycles; more information to help you make an informed decision.

However, I do feel like you are taking a risk and using your experience to justify it. We wear gear on a motorcycle to protect us in the event that we crash, not because we believe we are going to crash. Likewise, when a tire has gotten to the point yours is, you change it. Not because you know it is going to fail, but because it could fail.

At the end of the day it is your decision. I truly hope you don't have a follow-up thread that reads like an accident report.

[MrBrownTX]

Glad to hear that Kendas are reliable tires. My local bike shop said those were the best deal they could get for me. $150 for a set and $70 to install. That's half the price of what the Kawasaki dealer wants to charge.

[highpsiguy]

There is frugal and there is cheap. I take it as a compliment when called frugal. Being called cheap...well thats fighting words. $60 bucks gets you a new Kenda761 ...oh yeah you already got one. Don't get hurt getting the goodie out of a motorcycle tire. Personally, my life is worth more than $60 bucks.

[CynicalC]

Originally Posted by MrBrownTX

Glad to hear that Kendas are reliable tires. My local bike shop said those were the best deal they could get for me. $150 for a set and $70 to install. That's half the price of what the Kawasaki dealer wants to charge.

The 671s are like $105 shipped from rockymountainatvmc.com front and rear.

[FrugalNinja250]

Originally Posted by highpsiguy

There is frugal and there is cheap. I take it as a compliment when called frugal. Being called cheap...well thats fighting words. $60 bucks gets you a new Kenda761 ...oh yeah you already got one. Don't get hurt getting the goodie out of a motorcycle tire. Personally, my life is worth more than $60 bucks.

Coming up on 26,000 miles. I've got a long trip planned for the end of next month, I'll probably change it before then. Tire's completely unchanged last two thousand miles.

[MrBrownTX]

Originally Posted by CynicalC

The 671s are like $105 shipped from rockymountainatvmc.com front and rear.

wow cool, thanks!

[CC Cowboy]

Frugal, there is someone on here selling used tires. They could be right up your alley.

[coondog]

I'm thinking of the rock tires on the flinstones, they last forever but the ride is ****. frugal don't know it cause all he's ever had are rocks, even invested in futures. LMAO, you can get a set of beautifully soft compound tires, even "economy" ones and enter the 21st century, all for $120 plus delivery. And with all the diablo and mt75 name dropping for pre and post gen ? come on!

[FrugalNinja250]

Originally Posted by coondog

I'm thinking of the rock tires on the flinstones, they last forever but the ride is ****. frugal don't know it cause all he's ever had are rocks, even invested in futures. LMAO, you can get a set of beautifully soft compound tires, even "economy" ones and enter the 21st century, all for $120 plus delivery. And with all the diablo and mt75 name dropping for pre and post gen ? come on!

I was unable to decipher the meaning of this post, sorry...

As an extra note on the tires, it's been raining pretty heavily around here lately, makes me think I'm in the PNW except it's 20 degrees hotter. The Kendas are great in the rain, haven't had any kind of slippage or hydroplaning at all. Most of the miles on the bike are dry highway miles, though, not because I don't ride in the rain (I do) but because most of the time we're in a drought.

[BlackNinja]

Originally Posted by jmgrande

Agreed. This sounds extremely dangerous and like a disaster waiting to happen...

I would NOT ride on tired that have plugs in them.

How many properly installed plugs have you seen fail? I used to work as a tech for years at a garage, and have literally plugged thousands of tires. I'm still rocking a perfect, zero failure rate. I'll use them.

Edit: I've also plugged tires on my old 1000cc sport bikes, front and rear tires. Nothing takes the winds out of your sails more than seeing a nail in your fresh Pirelli that literally has less than 100 miles on it. They'ved held up to extended 150mph+ trips just fine. If my 250 can't break 100...I think I'll be ok.

[CZroe]

Originally Posted by bob706

Don't quote me but don't a majority of motorcycle tire failures occur when it's on its last 10% of life?

Technically, the point of failure is 0%. Anything else is an estimate.

[vkuchhal]

24K is a lot of distance...

[FrugalNinja250]

Originally Posted by vkuchhal

24K is a lot of distance...

Just turned 25K miles on the tire, no change in the last 1K. or (can't decide, hehehe).

[Green Streak]

That is impressive mileage for a motorcycle tire. I have never gotten close to that. But I have always used stickier tires. I was lucky if I got a full season out of my rear tire, until I got the new gen. These stock tires are lasting longer than anything I have had. But I don't like them in wet conditions. When you say it is squirrely when upright, is that just in the rain or what?

[want1sobad]

not to threadjack, but i have just under 14k on my bt45 rear tire. i'm down to the wearbars, but would not consider the tire to be dangerous.

btw, i'll be changing it this weekend...

so for those that rack up a lot of miles commuting and have a newgen, bt45's are fantastic.

[FrugalNinja250]

Originally Posted by Green Streak

That is impressive mileage for a motorcycle tire. I have never gotten close to that. But I have always used stickier tires. I was lucky if I got a full season out of my rear tire, until I got the new gen. These stock tires are lasting longer than anything I have had. But I don't like them in wet conditions. When you say it is squirrely when upright, is that just in the rain or what?

If I'm going straight down the road with no significant cross winds and get hit by a cross wind gust the steering feels fairly light and it turns away from the wind a bit. Squirrely is probably not the best word, because it's not a sensation of loss of control. It's more like there's less "rotational friction feel/inertia" in the bars. Cornering is unaffected near as I can tell, but I am a conservative rider so don't corner with scraping pegs and have no intention to. Rain riding is unaffected, and I've ridden moderately heavy rain recently (and will the next few days it looks like).

[vkuchhal]

I suppose for your case.. the company has given you their best set of tires...
For your case i think they will last 28k.. which is 2.5 times normal..

Get your tyres checked in guinness book of world record..

[DR1300R]

I too have plugged many motorcycle tires with no failures, would not hesitate to plug another..

Great thread..

[MrBrownTX]

Originally Posted by CynicalC

The 671s are like $105 shipped from rockymountainatvmc.com front and rear.

Today is payday, those tires are ordred! Knuckle Head and Sons Chopper shop where I live in Caddo Mills said they will install tires for $70. That is $50 cheaper than the Kawasaki dealer here.

[CZroe]

Ninjette member had a plug fail recently:
http://www.ninjette.org/forums/showthread.php?t=74316

[gfloyd2002]

Originally Posted by gfloyd2002

lol, well if anyone is riding a scalloped tire to 24k miles, I'm really glad it is someone who is worked as an analyst regarding reasons for tire failures. Definately not for someone without detailed tire knowledge.

And thank goodness, no, never had a motorcycle tire fail at speed. Car tires, yes, and that was scary enough. I can guess at failure sequence, though. It would be 1) Driving around with a grin enjoying Ninja; 2) FFFFUUUUUUU!; 3) Who am I and why do I have all these casts?

I can know report that I've had a tire fail at speed. And I can now confirm that the failure sequence ended as reported, with empahsis on FFFFFUUUUUU! Thankfully, step 3 avoided due to luck and good bike control. (But mostly luck.) The failure sequence started with error in judgement on my part - reliance on a sketchy roadside vendor in a developing nation offering to repair my tire for US$2.50, then relying on said repair. I wouldn't draw too many conclusions about the safety of plugs from my experience.

[FrugalNinja250]

Well, got 27,500 miles out of the tire. Inspection of the plug from both sides showed it unchanged and intact. No signs of any impending failure on the tire in any mode. I would still have continued riding the tire but I'm headed out of town on an extended high-speed trip and decided to go ahead and install the new Kenda K671 (which I've had in stock since last fall).

You can see the plugs just down from the top of the picture, right in the middle groove.

All in all, I've been most pleased with this brand and line of tires, and will continue to use them.