I bought new tires for my 1977 Triumph motorcycle which are?

Question

only 5 years ago. Dunlop K70s. The bike is kept in a garage but very seldom ridden. The tire walls are cracked and the tires need to be replaced. Only about 300 miles on them. Bike is in a garage and covered year round.

Why? Should I ask Dunlop for replacements as this seems wrong?

Answer 1

Rubber just has a way of ageing. That shiny black stuff on new tires is not only for cosmetic Porpose but its also a preservative to help the rubber from cracking. The 300 miles you put on them wore all that stuff away. Once a tire is subjected to the elements its biological clock starts ticking. Its not dunlops fault. The same would have happened with any brand.  

Answer 2

John,,'bleive it or not 5~6 Years is the average max lifespan recommended by most tire mfgrs.

20+ yrs ago ,,Age was "not an issue" because nobody made it an issue.

"Dry Rot" was apparent ,,at least Eventually,,,and then it was time for tires.

On Bikes specifically,,,only Rarely do Bike Tires Over-Age before wearing out.

In the last several years,,,the Age issue has moved to the forefront  of tire safety.

Obviously it behooves the Tire Mfgrs to sell tire more frequently.

But with 5 ~6 Year expiration interval,,it's just as obvious  it's NOT a marketting ploy to sell more tires.

Modern Tire Compounds have changed in such a way that  most characteristics are improved.

Including Wear Life--Tread Life,Carcass Life,etc.

Much of that has come at the expense of CALENDAR Life.

Tires from 60's,70's had much more "primitive chemistry"

ie,,generally More Carbon in the rubber.

So they Aged better.

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Here's perhaps an even MORE IMPORTANT point in the matter.

You BOUGHT your new tires 5 years ago----

There's No Tellin' how Old they actually were at the time of Retail Sale.

(Actually,,they should have a Date Code on them)

It's Possible they were several YEARS old before You ever bought them..

Even if that is the case,,I doubt You'd have any recourse with the Seller about selling you "Old Tires",,,,because at this point so much time has passed since purchase.

I'm sure None of the above is what You would have Liked to hear about the situation.

But I also trust that You understand it's something You NEED to know,,,for the safety of You & Your ol' Triumph.

Neither one of ya needs to go down at Hiway Speeds  for Any reason,,, & especially not cuz of a tire failure.

You can search the net using terms like,,"TIRE AGE" and get more results than you can read.

It's sorta quietly gotten to be a BIG DEAL.

Here's some example excerpts:

http://www.motorcycleanchor.com/motorcyc...

"....Additionally, all motorcycle tires are normally marked with three or four digit code on their sidewalls, which represent the date of manufacture (the first two digits are the week of the year, the last digit is the year of the decade it was manufacturered in). Since modern cycle tires are only good for about five years from the date of their manufacture (the time period it takes the various compounds that keep the tire pliable and strong to evaporate out), knowing which year of a decade it was manufacturered is normally enough. Example: 011 would be a tire manufactured in January (1st week) of 2001. 118 would be a tire manufacturerd in the 11th week (between the 13th and 19th of March) of 1998 (since 2008 hasn't arrived yet, as I write this). As a general rule, newer tires are better, and we recommend you buy tires manufactured within the past 12 months whenever possible ..."

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http://en.wikipedia.org/wiki/Tire#Danger...

"....Research and tests show that as tires age, they begin to dry out and become potentially dangerous, even if unused. Aged tires may appear to have similar properties to newly manufactured tires; however once the vehicle is traveling at high speeds (i.e. on a freeway) the tread could peel off, leading to severe lost of control and perhaps a rollover.

The date of a tire's manufacturer is found on the rim, to the right of the product code. The date code is often found on the inward side of the tire, so if they are already installed on the vehicle, the person has to lie underneath the car with a flashlight to check the dates. The date is a four digit code WWYY, with WW denoting the week (1-52) and YY denoting the year.

Many automakers and several tire manufacturers (Bridgestone, Michelin) have recommended a six year limit on tires. However, an ABC's 20/20 investigative report by Brian Ross found that many major retailers such as Goodyear, Wal-Mart, and Sears were selling tires that had been produced six or more years ago. Currently, no law for aged tires exists in the United States.[18][19] "

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I 'spose You could consider Tires to be sorta like Groceries,,,

in the sense that Eventually they'll Go Bad,,,whether ya Use them or Not.

The GOOD NEWS is that Ya discovered it,,,without eating it.

Take care,,,and get that Triumph out & about a lil' more often.

Answer 3

It has been my experience that bike tires generally cost more than car tires, and don't last anywhere near as long as car tires. If you are not riding often, I suggest buying an inexpensive set of tires for it. They make some inexpensive "off brand" tires that are still safe and reliable. That way every few years or so when you need new ones you're not wasting exsessive amounts of money.