Tyre Age

I felt a bit of rear slippage pulling out of some corners today on the first decent test ride since putting this bike together.
I was hoping it was my paranoia but after looking at the rear tire (just hit 200 fresh kms since putting it back together on this existing tyre) I'm thinking it should go.
The thing I was wondering was about the manufacture production batch stamp.
Bridgestone say the last 4 numbers signify the weeks(2 digit) then the year(2 digit) and 6 years is getting old. I can't find whether Pirelli follow the same rule but if they do... does this mean this tyre is, how old?!


Anyone know whether the production stamp coding is universal?
At least I took the brake shoe advice and put new shoes in.

 

I can only see 3 digits in the pic 081, what is the last one? Most tires use the 4 digit where the first two are the week and the last two are the year, unless they were made before 2000 then there are 3 digits.

 

The U.S. Department Of Transportation (DOT) required beginning in 2000 any motor vehicle tire sold in the U.S. must have a standardized four digit date code. The first two digits signify the week of manufacture and the second the last two digits of the year.

Before 2000 there was no standard and each manufacturer used their own proprietary codes (at least in the U.S.).

Since that tire has a DOT compliance mark and a three digit date code it was manufactured prior to Jan. 1, 2000.

 

I dont think i could bring myself to install or run a tire that was made before Y2k, shoot mine were made in 06 on the bike i just purchaced and dont even look as good as yours. Still working on mine though but i will have fresh meat on mine to start out with.

Yeah a bike that is 30yrs old like my 80 XJ650 is getting a good check up before i hit the ground running. :idea:

 

In answer to your original question, it's not QUITE as bad as you first thought; the little triangle after the 3-digit code indicates 1990's instead of 1980's, so it's a tire from the 08th week of 1991.

The pre-2000 code was WWY (two digit week, then the year of the decade.) The triangle was added to differentiate between the 80s and 90s and then switched to four-digit date coding after 2000.

Any tire with either NO date code or any three-digit date code is TOO OLD.

Six years max.

 

forget the date code, just look at the tire its thrashed. probably because you're using US only tires in australia...

 

You can use US tires in Australia, but you have to mount the tires with the arrow turning backwards. It's caused by the same phenomenon that makes the water in the toilet swirl the opposite direction.

 

Great to know about the date codes, thanks and *Phew* I'm glad the tyre is only 18 years and 8 months old instead of 29 years and 4 months, I was starting to become concerned!
and Yes we do ride our bikes facing backwards here

 

If you think about it, the water swirls the same direction- - you're just looking at it from underneath !!

 

Fixed!
Metzler Lasertec 120/90-18
New rubber looks good! and better when all that wax is gone.

 

cds, good call! I am glad you got rid of the old tire. It's just not worth the risk

 

hi cds1984, i have recently bought and xj750p ex wa police bike, and i feel the slippage on rear tire like you noticed, and i think my tires are old, but still have a bit of grip on them. is it still safe to ride on a tire if it is 7 years old but has plenty of grip from not much usage? Also having never bought tires for a bike, can you recommend anywhere cheap in Perth? i live in Midland.

 

Looks much better, ride safe.

 

It's not a good idea. These bike use tubeless tires, you're taking a chance on a blowout which will almost certainly destroy the rim at the very least if it doesn't wreck you.

 

Hi Kpcart,
One thing I came to realise after doing the tyres is that the slippage was caused by the swingarm bearings being totally shot.

In essence the whole backend was moving about and it feels like the tyre is slipping instead.

Put the bike on the centre stand and sit down on the floor behind the bike, then try to wiggle the wheel left and right or in a twisting motion... if it has play then you probably have the same problem.

I'm just doing another 750P, with a 900 engine, and the swingarm bearings in that one were totally dry with one side rusted up and mangled (the bearing cage that is) so I think its a common fault at this age. It was a bit of a battle changing those ones I have to tell you.

Swingarm bearings 2 x 30203 from BSC bearings
Swingarm seals 2 x 25x40x7 from BSC bearings work but originals are 25x40x5 from Cullys Yamaha

I bought my tyres from the Bike Doctor(Aka Bike tyre city) on Scarborough Beach road and I got a new front and rear fitted for $408.90... which hurt a bit but after the swingarm rebuild I feel fairly stuck to the road nowadays.

 

I replace mine that were 10 years old. Old tyres do go hard and provide less grip. Went to tyres for bikes in Vic Park $150 for the front $165 for the rear.

Bridgestone BT45

 

...another thing with brand new tires is don't take any corners hard until you've got a few k's or miles on them.
Buddy of mine had new tires put on his 78 Honda 750, brought the wheels home, bolted them on the bike, got to the end of his driveway, gassed it, spun out, wrecked the left side of the bike and was on crutches for three months. New tires are slick, so take it easy, scuff them with sand paper.
He is an experienced rider, but got carried away (literally).
A lot of people think that a new set of tires are safe, they're not until they are broken in.

 

Good info there I have new D404s and was taking a corner on asphalt. My rear tire started to slide at 15mph with a little power on it.


Also quick question I have some bridgestone tires that were made in 09 with lots of tread left. They have some small cracking like dry rot around where the tire meets the rim. Should this be safe or not? The tires are on a 1993 Honda 750 Nighthawk I bought a few days ago.

 

You sure they were made in '09 (in which case they're barely two years old) and not 1999?

 

Yeah they have the 4 digit post 2k code. I live in new mexico so it is real dry here. Looks like this http://kydrives.net/2006/11/13/tire-dot ... our-tires/