Have a lady friend who owns a very nice 1992 FXRS she bought brand new from Bob Dron HD in Oakland, California. She recently asked me to start servicing the bike for her.

She is not a high miles rider. Her rear tire is 6-years old but definitely has a lot of tread left on it. The tire shows no cracks on the sidewall or on the deep part of the tread. Never encountered this situation with any of my bikes. I undertsand that rubber hardens as it ages and can pose a safety/reliabilty issue.

I would appreciate thoughts and comments regarding at what point (2 more years if her riding habits remain the same and the wear is within specs?) I should recommend that she replace the rear tire.

 

There's a lot of variables, nothing is carved in stone.
But I've seen the recommendation of 5yrs several times.
We see it all the time "new" old stock tires being sold for cheap.
Is the 5yr thing part of the tire industry just wanting to sell tires? Perhaps.
But there are reliable stories of tire compounds beginning to break down after several years of even no use at all.

So IMHO, she's right on the edge already with it being 6yrs.
Again, it's a judgment call that needs to be made with the variables of care and condition considered with first hand inspection.
Some guy's will run tires down to the cords, others replace them when they begin to lose grip.

My life is connected to the road with two small rubber contact points, new tires can be had for $150 and up.

 

If you don't know the correct answer, then you shouldn't be working on her bike. Did you ever consider what could happen if her tire blew out on the road? I doubt it. Buy a new tire.

 

Like was said, 5 years is a general rule of thumb. I've heard as few as three years. At six, definitely get new rubber. It's not worth the risk, especially if her tires are lasting her that long. That's a few hundred dollars every five years to make sure she has a good contact patch with the road.

 

With tire technology where it is today, I think 6 years is okay if it has been garage kept, and not exposed to ultraviolet (Sun) light. Some literature on the subject says up to 10 yrs under perfect conditions.

Being a geezer myself I say 5 yrs and I start thinking about it, so I'd rather just pay for new and not worry.

 

Let the Lady know what the recommended years are. Let her decide. JR

 

Dunlop recommends 6 years. I spoke to an engineer there in 2011. When I bought my 8 year old Garage Queen, with 2k miles, I changed the tires.
My friend who has been riding for 45 years, and very aggressively, laughed at me. He never worries about how old the tires are, unless they fail a visual inspection. So he may be right, but I'm not willing to take that chance.
http://www.tirerack.com/tires/tirete....jsp?techid=11

 

Of course the tire Co's are going to give a time limit it is in their best interest. Our muscle cars and old motorcycles have tires 25 yrs old and more. In all the years I have been tearing the streets up never once worried about tires other than making sure the pressure is up. Also never once had a problem with the so called "Hardened Rubber" syndrome.
Not all people have this experience what a shame and the wasting of perfectly good tires is even more of a shame.

 

A lot depends on storage conditions. My utility trailer, stored outside in WI, all year, had 12 year old auto tires on it, when they went Flat, just from cracking. My boat trailer has 16 year old tires, and they appear fine. But it's stored indoors in the Winter. I am going to replace them, this Spring. Which might be a mistake as all the trailer tires are made in China now.
And a muscle car tire failure isn't as catastrophic as a 2 wheeler. I have never been down, and I'd like to keep it that way.
I think it is a shame and a waste that a Muscle Car sits enough to have 25 year old tires. Drive the car.

 

My recommendation is to not take the chance. Tires are critically important on a bike. Many auto manufacturers and many tire companies have said that tire aging degrades tires to the point that 6 years is the recommended time for replacement. AND that is mostly by automobile related manufactures. Lose a tire on a car it's a pain, on a bike, potentially a capsize.
NHTSA has been looking at this for a while. Here is a link for some info.
http://www.tirereview.com/decoding-n...-aging-report/
Just google tire aging for more.
Better to be safe than sorry on a bike. Plus...the bike will ride and handle better with new rubber.