Ira B

You have to decide on how/where you ride and at what speeds.
On one outrageously steep downhill coming home I easily hit 50 MPH if I stay off the brakes (which is crazy but a lot of fun ) Not the place for questionable tires. I'm just getting too darn old to be doing any 50 MPH face plants.
I use the old food in the fridge standard when it comes to bike tires. If you are having a conversation with yourself that goes like...., "gee I wonder if this is still ok"..... it is probably not worth the risk.

SJX426 

Tubulars are often aged for a year or two prior to use. Many prefer the performance of an aged tubular. It may not be done as often as in the past. Storing tires in a cool dark place with low humidity is the best environment.

ultraman6970

Im using a 30 y/o tubular. With tubulars as long as the sidewalls arent dry or super dried is not a problem. When a clincher gets dry is just call problems because those things disintegrate.

Doug5150

Yes.

Rubber degrades as it ages. Most engineering references I have seen give a shelf life of 5 years for rubber parts, possibly 7 years at best. "Rubber" here means latex, as well as butyl and styrene-butadiene that are most commonly used in bicycle tires and tubes.

Most places online that do rubber manufacturing have a FAQ that will give the estimated shelf life of manufactured parts. If the part is in a plastic bag filled with nitrogen, stored in the dark and stored at freezing temperatures, then the shelf life increases to 10-15 years.

If you have a prized tire collection you care about, it should be stored in the dark (UV light damages rubber) away from any motors (ozone damages rubber) and ideally in a freezer (cold temps slow down degradation from atmospheric oxygen). But they're still gonna get old and go bad. How much and how fast depends on a lot of things. How lucky do you feel?

The casing strength loss is tougher to pin down. Modern references give a 10-year shelf life for either nylon or polyester working ropes (a really old,,,, like, ~50+ year-old,,,, bicycle tire would be made of polyester, not nylon). Both polyester and nylon begin to show strength degradation by the 15-year mark.
,,,,,,,,
The practical problem with tires is that the rubber on the sidewalls develops cracks, then road grit gets into the casing fibers and grinds them down that way. How fast that can happen is tough to estimate.

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Silicone-based "rubbers" last much longer, but most bicycle tires don't normally use them. One example of these is the gray non-marking tires used on wheelchairs.

puchfinnland

what gets me is the car tires can last easily 15 years or more if you dont wear them out first,

But bicycle tires start getting sidewall cracks after only 2 years?
are they to be replaced?
No way! each tire is a different situation, but I still have some tires well over 40 years old, covered with sidewall cracks,
Dont forget its the tire carcass that is holding the thing together-not the outside skin.

one set says USSR on them!! they are going back on the Gents 40's bike I am renovating.

at the LBS sits a sweet pair of Panaracers on a 80's Nishiki that are "like new" the client instructed to change them and the owner knows I got the hots for them.

wroomwroomoops

Is it not "CCCP"?

Anyhow, now I want, desperately, a set of working tires with "CCCP" on them.

mgb

OP here. I replaced the old tire with a new 28mm Conti Contact. The old tire wasn't cracked and was still flexible but the rim contained a lot of amber flakes and powder from the sidewall rubber and the bead looked pretty ragged. The new tire has a lot more rubber so I hope to get some good use out of it, but maybe not decades!

lostforawhile

the quality of tire rubber has really been deteriorating, I work with small tires in the aircraft industry, most are now made in China, and I can tell you when the company that makes them went from US manufacture to Chinese manufacture, the tire quality went all to hell, I know people at work who bought brand new chinese mountain bikes, rode them a few miles, parked them in the hanger, and in a year the front and rear tires on both bikes are shot. I cant name the company that switched to Chinese manufacture, but I've seen the quality drop first hand. I'm not trying to pick on china but many tires are now made there, I've personally cut them up on the band saw and seen the poor quality of the cords and rubber. I have a beachcruiser bike thats less then three years old, and the tires are so bad, I parked it until I can replace them.

lostforawhile

A 15 year old car tire is a bomb waiting to go off, tires used to last that long, I would never trust a tire to last that long today

FMB42

Sorry, but I do not agree with much of what you've said. The rubber of most any pneumatic tire works in conjunction with the casing. This makes riding on "tires well over 40 years old, (that are) covered with sidewall cracks" a bad idea. Such cracks can, and will, concentrate stress on the tire casing is ways that it was never designed for. I seriously doubt that engineers design tires with the idea that someone will continue to use them when the "sidewall is covered with cracks."


Knowingly and willingly riding on "tires (that are) well over 40 years old, (and) covered with sidewall cracks is (at worst) increasing the chance of taking a trip to the hospital, and (at best) being left stranded with a failed tire. Tires are just too cheap to risk either of the above scenarios.

Airburst

Interestingly enough, I think one can model a tyre as being made from a fibre-reinforced matrix, kind of like carbon-fibre reinforced plastic, with the rubber as the matrix and the cords as the fibres. I'm sure there's some way to work out the stress concentration produced by a crack in the matrix of a composite like this (i.e. a sidewall crack), given the relative proportion of fibre by volume and the elasticities of the fibre and the matrix.

Since the matrix in this case (the rubber) has a fairly low modulus of elasticity, I would think that almost all of the stress is in the cords even when the tyre is new, but I don't have the hard figures.

HillRider

This is a left-over from decades ago when the tread strip on high class (usually silk) tubulars was hand glued to the casing and not heat vulcanized. The tire was aged to allow the glue to harden and vulcanize over time. Also, these tires were aged in a dark cool place, not in the light and heat.

Almost all current tubulars of all levels are heat vulcanized and are as good as they are going to be right from the start. The fact that some mechanics still age tubulars is a tradition but no longer a technical benefit.

wroomwroomoops

Careful with Continental tire purchases: their quality is extremely variable between models. Top Contact, Travelcontact, Sportcontact, TourRide - all these have, nowadays, extremely short life. They seem to wear fast and get punctures easily, even if some puncture protection is claimed.

The problem is that some of the Conti tires are made in Germany, some in Russia and some... elsewhere. (China, S. America, Malaysia...). Maybe that's the reason for the extreme disparity in quality by model. I don't know, but I'd be extremely careful when choosing a Conti tire nowadays. Make sure you read some fresh reviews.

Kimmo

I'm with FB and puchfinnland. If the bead seats nicely and there are no bulges in the carcass, it's good to go, pretty much regardless of the condition of the rubber, unless maybe you need a lot of grip.

Comparing bike tyres with car tyres = fail, wrong.

As FB said, any impending failures are almost always noticeable as a bulge, and generally take a while to happen. It's all about the bead and carcass.

Burton

This.

Most cyclists are familiar with brake pads hardening up with age and braking less effectively. Tires aren't much different. They may not blow, but braking performance and ride quality will definately be affected. In the cases where the tire uses cotton threads, cracked rubber will expose the cotton to the elements. Heavy cotton tarps left outside are usually given a life expectancy of 2-5 years and have waterproofing and antimildew treatments. Polyester also has issues. UV radiation starts to break down polyester molecules very rapidly after the first few months of exposure. Nylon is pretty much the same - unless specifically formulated to resist UV radiation, the life expectancy of nylon is only 1-2 years. So if a tire starts to crack,the rubber has already lost some flexibility as well as the ability to protect the rest of the guts of the tire. Not necessarily an emergency, but certainly a good hint that its time to start thinking about replacements.

Shimagnolo

True. Bike tires operate at 2-4 times the pressure of car tires, but with a wall thickness a fraction of the thickness of a car tire. All these unrelated failures I've had on bike tires, but never on a car tire:
- New tire started ripping cords upon first inflation.
- Tire started bulging at the sidewall due to cords ripping away from bead.
- Sidewall blew out while hanging in the rack.

fietsbob

My Nokian Studded tires are 20 years old, so What tire and how was it constructed is a Big Variable.

Burton

Agreed - as well as where they were stored. Summer heat and continuous exposure to UV is hard on rubber. Winter tires are generally made of a softer more elastic compound, see fewer daylight hours in use and are normally stored indoors for the summer.