You guys still remember changing spark plugs every 10k and set the points every 20k?
We had 84 Volvo where timing belt suppose to last 50k.
Well it lasted 58k and 59k on the second one.
Older cars were way much simpler. Took me less than 1hr on the side of the road to put new one.
Now timing belt on European cars is 4-digits job.

 

The materials they use in belts today don't crack as quickly as the old ones do. Go to the website of a belt manufacturer like gates and dig around and you can probably find a link where they will send you a belt gauge.

The belts today will wear down and not perform as well, or might fail with no visual warning. I replace mine every 100,000 miles. I've got 357,000 miles on my truck and I don't think buying 3 belts along the way has been asking too much.

I do keep the most recent old one handy as a spare just in case, but if a belt comes apart at highway speed, you really need to worry about what else it might take out. Not just having a broken belt.

 

I always get kicks from the "keep the old one as a spare".
If your new belt will break, what will the one several years older do?
I witnessed few serpentine belts failure and they didn't do any additional damages. Those belts are relatively light and have not much inertia.

 

The old belt will get you by until you can replace it with a new one. It would be silly to carry around a new belt, since it would start degrading for several years while you carry it around before it even gets used. I've always carried my old belts in all my cars, never needed them yet, but I still have them just in case.

 

I noticed that in my maintenance guide after the fact. I'm not impressed. But, she only has 7K on her so I have a while before I have to worry about that.

 

On my old F-150 with a 302 CID, that advice saved me. I broke a belt in Wyoming, out on the middle of nowhere. Threw on my crusty old spare and drove about 45 miles to an auto parts store, where I could purchase a new one.

I will admit it is rare, but it does happen.

 

That would indicate that in previous change you replaced good belt with a cheap one?
Being DIY -I prefer carrying new belt as a spare and replace old one when shows definite aging. If the new one will spend 3 years under the seat -I don't mind.
Fact is that I have 4 newer used belts from the cars I sold. For mysterious reason -they are about 1" apart in lengths. You would think it shouldn't be too difficult to move the belt tensioners 1" and make less belt sizes?

 

There are such things as freak accidents...like manufacturing defects, like a rogue stone or pebble that gets caught and tears up a new belt. Just because a new belt broke doesn't mean that an old one will too.

And yes, carrying a new belt is silly. By the time you get around to needing the spare, it's already an old belt anyway.

 

Only partly true. The rubber deteriorate mainly with UV rays and than with high heat. I still have 30 years old tire on my motorhome's tag that I keep as experiment. The tire kept in the shade shows no aging and holds 90 psi for full year.
Than how do you know the belt you get from NAPA wasn't waiting for you there 5 years?

 

Because of the volume they move.

 

There's really no UV rays in the engine compartment so by your logic an old belt is a new belt too. Do you think rubber doesn't deteriorate also by drying and cracking, especially in dry climates like a desert?

I rather take my chances with buying a new belt that could be new or could be 5 years old, rather than pulling a belt out of my trunk that I KNOW was sitting there for 5 years AFTER I bought it. That's really not a hard choice. And besides, in 5 years, they could have come out with a belt made of unobtainium that was 100x stronger and lasts to 1 million miles.

 

Just like with any "insurance" we can discuss endlessly what is just right and what is too much.
My tractor drives on 26 years old tires and 26 years old V-belt. I replaced belt on our sedan at 210,000 miles and not being original owner -I assumed the belt was original. The same on my Superduty. I bought it 5 years ago and added 50,000 miles. The belt was old when I bought the truck, so I am pretty sure it is original at 240,000 miles and still looking good.
If you feel the need to replace the belt every 50k- it is your money.

 

The "spare" belt isn't meant to be a replacement - only to get you to a place where you can get a new one. Doesn't really matter that its been sitting in the cab for a few years if your stranded 100 miles from the nearest town w/ nothing but empty hwy btw. Beats walking that 100mi in 100 deg heat any day. For me - I'll just keep carrying my spare belt - just like my spare CPS. If you've never been in that situation I don't think you can fully understand why having it is cheap pc of mind.

 

I drive on deserts where nearest service with parts is over 50 miles all the time.
Last summer had scary moment when leaving Nevada, on Mojave desert my coolant tank started to leak. Fortunately the leak was small and with 3 gallons of extra water I made it home where I could buy new tank from the dealer. Tank failure is pretty common as well. How about recommending replacement every 30,000 miles?
Than add PS pump, turbo, injectors... ..

 

I allways have a spare used belt in the truck or car as a emergency replacement, just in case. back in my day's in a gm dealer they would not warranty a belt with cracks through the ribs on the belt, it was just normal wear and tear but if the cracks were into the substrate gm would replace it. if your getting alot of cracks it wont hurt to replace it anyways, just hang on to the old one and hide it behind the seat