I have a set of Schroth Rallye 4, both driver and passenger. The tags on the belts say week 15, year 00, which I assume means roughly April of 2000.
Am I reading the date correctly? And, if I am, what does that mean about their usefulness? They've never been through a crash.
I would assume they are still ok safety wise, but may not be legal for certain types of racing depending on that series' seat belt rules. In our autox club, we canning use outdated belts (2 years for sfi belts) which in my opinion is stupid since stock belts are good forever.
The materials are different between stock, SFI and FIA rated belts. The webbing used in SFI belts loses 50% of its strength after two years of exposure to UV, thus the expiry dates.
EDIT - see the chart below for degradation percentages
And since everybody leaves their racecars outside 100% of the time ..... Wonder how hard it would be to incorporate a UV exposure tag, or maybe a dye that turns color.
The Schroth belts are DOT approved, so I'd feel as safe with them as I would with the stock belts in any '01 or older vehicle.
so, if I list them in the $200X classifieds and ask $20 for the set I might get a taker?
If nothing else, they're perfectly good for autocross. Heck, for $20, if they fit one of my cars, I might be interested. 
In reply to White_and_Nerdy:
Hey, I know you! I recognize that avatar, #54 red Miata on ice! Mr. Ringer Autocross Expert who got a wicked good auto-x time in my #54 Saturn at the 2004 Challenge!
If you're still in touch with Matt S, tell him that "Boris" went to the boneyard today (two hours ago). I'm in mourning. (Where's the crying "smiley" when you need it?) Seriously.
The belts were the last thing I pulled out of Boris. I hated the idea of anything useful going to the boneyard. I even pulled out the Jensen speakers.
Drop me a line by way of Facebook, we can work out a way to get those belts into your hands.
The idea that belts are only good for 2 years is a myth! Pushed by the belt manufacturers to force racers to have to buy new belts every 2 years. Test have been done by various labs. etc. and 10 years is a good number to use a belt for racing. Most racing organizations; but not all use the 2 years rule. The whole thing is an overreaction to the death of DE at Daytona IMO. How is it that the belt material used in OEM seat belts are not required to be replaced after no many years? Are they not exposed to UV, heat, humidity?
It's different material. All you have to do is touch them to tell. Different racing organizations (ie, SFI and FIA) require different materials and thus they have different lifespans. You can feel the difference in those as well.
I'd love to know more about what's used in factory belts. It's a much different weave than race belts. Someday I'm going to dig deep into the science of this.
You'll find this chart at Simpson and at Schroth, but I believe it comes from Dupont testing done in the 60's - look for "Light and weather resistance of fibers", bulletin X-203.
My bet that the testing was done using constant 24/7 UV light on the material in question. I don't think you can equate that to what belts on race cars are subjected to. My belts are 1 1/2 yrs old based on the date tag. They have seen only 2 days of exposure to direct sunlight when the car was at a track event otherwise it sat in the garage! Just not the same conditions at the test you mentioned. Plus the test results are over 40 years old.
What we really need is new data from an unbiased source!
Your bet would be wrong. I'm still trying to see if I can find the text of the full report, as I'm curious. I've found excerpts. Here's the biggest part of it:
http://www.hse.gov.uk/pubns/sir59.pdf <- start at page 102, and note the much more complete graphs from the testing on page 105.
From the synopsis of the report:
"Comparative data on strength retained after outdoor exposure in Florida for periods ranging from 1 to 36 months are presented. The effects of different exposure conditions and fibre characteristics on the outdoor durability for direct and ‘under glass’ exposures are illustrated"
Still, not laboratory 24/7 exposure. Even under glass, which cuts exposure.
"After twelve months of exposure, the test items exposed under glass retained more strength than duplicate items exposed to direct sunlight. This was expected since the shorter, more harmful, ultraviolet rays are filtered out of sunlight by ordinary window glass."
Interesting - given the choice, go for a bright shiny color.
"The light resistance of a virtually all fibres dramatically improves when black pigment is dispersed in the polymer during fibre manufacture. Conversely, the light resistance of many fibres decreases when the amount of delustrant added during fibre manufacture is increased. Thus, bright fibres are usually more durable than semi-dull fibres which, in turn, are more durable than dull fibres. The effect of delustrants is very evident with nylon fibres, but is minimal with dacron polyester fibres."
Have a look at an SFI or FIA harness against a factory belt sometime. This would seem to imply that the big coarse thread used in harnesses should be superior to the fine stuff used in seatbelts in terms of UV resistance.
"The light resistance of a yarn increases with the denier of the individual filaments, probably because less radiation penetrates into the interior of the fibre. DuPont experience and tests show that this also applies to ropes where the outer layer of fibres apparently shield the inner fibres from radiation damage. For ordinary textile products, neither the size of the yarn nor the thickness of the fabric appear to have a significant effect on light resistance - possibly because none of the individual filaments is completely buried within the yarn or fabric."
Is this test representative of all race cars? Of course not. It's a good thing, or Nylon belts (note the trademark, Dupont tested a Dupont product, so you know Dupont wants to make it look bad) would be down to 13% of the original strength. Is two days of use in an 18 month period representative of all race cars? No, of course not.
If the guys who do the science to develop and test materials are too biased, I suggest you trade off the tinfoil hat for a white coat. Get on it, develop some new data. How do you propose we test for the degradation of materials? The problem, of course, is that not all vehicles are treated the same way. The standards boards - who are there to protect drivers - have to come up with something. How SFI came up with 2 years and FIA came up with 5, I don't know exactly. They're probably conservative and assume the car will be treated reasonably well, but you can't assume every race car gets stored inside permanently. The suggestion of a UV tag is a pretty good one, if that's the primary concern.
We all know tires degrade over time, even if Aunt Sally still has the original rubber on her 1990 Accord, and that helmets degrade, which is why Uncle Rob's old race helmet from 1966 is always full of that brown dust. Why do some people refuse to accept the same about belts?
No one here is saying that you should use 20 yr old belts for racing! I am fully on board that a resonable time limit should be set for replaceing racing belts. I just feel that 2 yrs is not a resonable limit! The organization I have raced with and will race with later this year has just changed the limit from 2 yrs to 5 yrs based on through research by our Chief of Tech.The way the change was done was if a set of belts show anykind of aging anytime between the 2-5 yrs period of the belts life a notation will be made in the cars log book requiring the belts to be replaced before the next race.
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