Original tire?

PostPost by: Yum-yum » Tue Oct 20, 2009 2:27 am

When I bought my 1969 S4 in 1988 it had this 155HR13 Dunlop SP Sport mounted as the spare. I've never bothered to change it through the years, and never needed to use it. I'm finally planning to recon and repaint the wheel silver to match the rest and have a new tire mounted in its place for a reliable spare. What are the odds this was an original fitment tire? The tire says it was made in Great Britain, the only stamping is a J over a BM in a small circle. Anyone know how to read the old date codes? Just wondering. It is tubeless.
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PostPost by: 1964 S1 » Tue Oct 20, 2009 3:00 am

Greetings, the odds are pretty good that's the original spare tire, but it's unsafe to use a forty + year old rubber tire over thirty six miles an hour.
I'd replace it which then makes it worthless hazardous material for landfill disposal. Unless of course you live in one of those avante garde regions of the planet where re-cycling makes sense and saves money and you can turn that old Dunlop into a parka or highway resurfacing material once the glass is added.
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PostPost by: Frank Howard » Tue Oct 20, 2009 3:16 am

Alex,

I'd also be willing to bet that it is original. Regardless, I'd keep it as a spare. In a pinch, I'm certain that it would get you well past the next tire repair station and that's all you'll ever need your spare for. (OK you guys, fire at will!)
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PostPost by: alexblack13 » Tue Oct 20, 2009 7:58 am

I agree with frank. Keep it as a spare. If used just remember you have it on and take it easy. It will get you home ok and that's all it needs to do. I must admit I don't carry the spare wheel in the car and have sound deadened / carpeted the spare wheel area and made it into a carry this n that space. I carry a decent tool kit and replacement hoses/ Alt' drive belt etc etc. And a couple of emergency tyre inflator in a can thingies. Saved a bit of weight also.

Have fun.. & ... Greetings from Scotland... :wink:

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PostPost by: Galwaylotus » Tue Oct 20, 2009 8:25 am

1964 S1 wrote:it's unsafe to use a forty + year old rubber tire over thirty six miles an hour.


In fact, generally it's unsafe to use a tire over about six years, no matter what the speed. Many of the major auto manufacturers have issued reports showing the potential for delamination, etc. on older rubber. Even if not used and stored in a warehouse, the rubber does age and will be prone to cracking, delamination, hardening, etc. If you want to keep it as a "trophy", fair enough, but please don't have it in or on the car. It just isn't worth it.
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PostPost by: Yum-yum » Tue Oct 20, 2009 2:14 pm

Oh, I definitely plan on changing the tire for new. I'm getting interested in what would have improved in tire technology since then. I don't imagine they still use Rayon belts for example! I do plan to stay with the 155 width, though. Thanks for the feedback. Not sure yet if the old one will go to recycling or what.
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PostPost by: Ross Robbins » Tue Oct 20, 2009 2:48 pm

As the saying goes:"It can only be original once". With that in mind, I'll bet it is worth something to someone with an original car that uses it only for display. Hmmm, let's see, you aren't far from Jay Leno!

Seriously, I would keep it as a rare piece of history or offer it to someone who wants it...with full disclosure and signed waiver of liability of course. Don't just toss it. :roll:
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PostPost by: Yum-yum » Tue Oct 20, 2009 3:08 pm

HA! Leno and I literally bumped into each other a few years back at the Monterey Historics, both of us much more intent on looking at the cars. He's not that tall but his hair sure was big!
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PostPost by: msd1107 » Tue Oct 20, 2009 6:26 pm

Actually, Redwood City being close to Jay Leno is a matter of degree, since Redwood City is 350+ miles away.

But us SoCal people get to see Jay on a relatively frequent basis.

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PostPost by: avhation » Tue Oct 20, 2009 6:34 pm

Since the tyre has been kept in a dark place, albeit not a cool place, it may be in surpisingly good condition and free from visible cracks. If so, I too would recommend keeping it as a "get you home" or "through the annual test" spare. :wink:
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PostPost by: Galwaylotus » Tue Oct 20, 2009 6:42 pm

avhation wrote:Since the tyre has been kept in a dark place, albeit not a cool place, it may be in surpisingly good condition and free from visible cracks. If so, I too would recommend keeping it as a "get you home" or "through the annual test" spare. :wink:

That could be a fatal mistake. A 40 year old tyre will not be materially the same as it was when new. The chemistry of the rubber changes with time and even if no cracks are visible it could fail suddenly. Not worth the risk in my opinion as the value of the car is much greater than the price of a new tyre and the value of a human life puts both of the previous in the shade!
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PostPost by: Frank Howard » Tue Oct 20, 2009 9:51 pm

All tires become more dangerous as they age. Compared to a 2 year old tire, a 4 year old tire is not as safe. Compared to a 4 year old tire, a 6 year old tire is not as safe. I could go on an on. It's a matter of degree. It's also a matter of the quality of the tire as well as how the tire has been taken care of. Someone may say that driving on a set of 10 year old tires is putting everyone on the road at risk. Someone else may say that driving on a set of 5 year old tires is putting everyone on the road at risk. Who's right? Both of them are. And the guy who claims that driving on a set of 1 year old tires is putting everyone on the road at risk is right as well because 1 year old tires are not as safe a 6 month old tires. Again, it's just a matter of degree. Calling tires safe or dangerous depends on where one draws the line. I saw a morning TV show where a tire manufacturer was claiming that all tires should be discarded after 3 years as he deemed them to be unsafe. Well, compared to 1 year old tires, they are more dangerous, but I have no doubt as to what his motivation was.

I find it a little silly to be driving in cars that offer absolutely no side impact protection and feeling safe because one's tires are brand new. If safety was a primary concern of the people on this site, we'd all be trading in our Elans for Mercedes Benz, Volvos, and Saabs. And for those of you who want to argue active vs. passive safety, consider trading your Elans in on Miatas. They offer the same accident avoidance handling with the addition of side impact protection as well as front and rear crush zones.
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PostPost by: dusty » Tue Oct 20, 2009 10:31 pm

You are right but this doesn't mean that we shouldn't try to make our older cars as safe as they can be. The age thing doesn't just apply to tyres but to all mechanical aspects of the car, brakes, shocks, bushes, mountings, seatbelts etc etc. All perish with age regardless of the mileage the car covers each year.

And don't rely on the annual MOT as validation that your car is safe, I've seen some woeful cars recently that supposedly had a current MOT.
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PostPost by: Yum-yum » Tue Oct 20, 2009 11:09 pm

I appreciate all perspectives, but I will be changing out the tire soon. This is part of a desire to return the car back to its glory as a daily driver. Where in the past I would have relied on this spare, maybe I'm wiser now and value safety more. I will say that I would feel more confident on this tire as a spare than the space-saver spare provided on my Honda Element, though I wouldn't exceed 35 mph for long on that one either.

The visual condition of the Dunlop is outwardly good, there are no cracks in the rubber, but the surface has hardened to a "plasticky" consistency. As a spare in potential wet conditions I would not expect it to provide much traction. I will consider offering it up for free to anyone who may want it (Leno or otherwise!), once I have it replaced.

We have no required annual safety inspections here in California. At least locally I would say the vast majority of the cars on the road are newer than 10 years old and annual inspections would prove rather moot. I suppose I could be cited for having unsafe equipment and would be liable for the results of any such irresponsible actions. I am glad my elan no longer requires a regular smog check (as of about 10 years ago) as it used to be hard to find anyone who would conduct it.
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