Dunlop K81 “5817” Tire Date Code?

Slammin · Apr 19, 2020

I just picked up a 73 commando that had been in storage for many years. The PO told me he had not replaced the Dunlop K81 tires, so I checked the code to find out the production date. It says 5817. WTF? Week 58? And for sure they were not replaced since before 2017. Is there a non-traditional date code method for these?

L.A.B. · Apr 19, 2020

I don't think that's a date code. If they are original 70s K81s then they may not even have a date code. If pre-2000 then it would be a three-digit code.

https://www.oponeo.co.uk/blog/tyre-s-date-of-manufacture

Slammin · Apr 19, 2020

Hmm, no 3 digit code present. Anyway, they are coming off and new rubber will be installed.

cyclegeezer · Apr 19, 2020

Slammin said:
Hmm, no 3 digit code present. Anyway, they are coming off and new rubber will be installed.

Always a wise choice.

Slammin · Apr 23, 2020

While I can't find a 4 digit code, there is a sort of 8 character serial number on the tire. The last 4 digits of the number on my existing tires are 0306 and on my new tires 0120. So, I have to believe it's the last 4 digits of this number. But even Dunlop doesn't reference this method on their web site.

L.A.B. · Apr 23, 2020

Slammin said:
So, I have to believe it's the last 4 digits of this number.

I don't think it is.

If it has a date code then I would expect it to look like the example below with DOT etc. 2BL prefix and appear as a separate number.

(Week 42 1998)

Edit: Where was it made as that would give an indication of age?

If "Made in ~~England~~ Great Britain" then it's probably pre-1990 as TT100 production moved to France around that time ("Made in France") some were made in Japan and the most recent made in Indonesia.

Slammin · Apr 23, 2020

So, it is as I suspected. Just spoke with a tech person at Dunlop. He confirmed the date code is the last 4 digits of the string of 8 characters. So, the new tire just received was produced in Indonesia the first week of January 2020. The tire on my bike was produced in Japan the 3rd week of 2006! I’d show a picture but can’t figure out how to do it without a URL link.

Tornado · Apr 23, 2020

Slammin said:
So, it is as I suspected. Just spoke with a tech person at Dunlop. He confirmed the date code is the last 4 digits of the string of 8 characters. So, the new tire just received was produced in Indonesia the first week of January 2020. The tire on my bike was produced in Japan the 3rd week of 2006! I’d show a picture but can’t figure out how to do it without a URL link.

Since you are a VIP member here (as the little green ear mark top left corner of your avatar indicates to me), you can add images using the "Upload a File" button appearing at bottom of the reply text box. Then just navigate to where your image file is located on your pc/phone and upload it. It gets placed right where your cursor was in the text box.

L.A.B. · Apr 23, 2020

Tornado said:
Since you are a VIP member here (as the little green ear mark top left corner of your avatar indicates to me),

The green mark indicates the member is signed in.

A VIP member has a light blue band with "VIP MEMBER" on it below their username.

Slammin · Apr 23, 2020

Figured I might as well join as a VIP anyway.

RoadScholar · Apr 23, 2020

I believe your decision to replace the tires is very sound. The tires you purchase will have a four digit date code which, hopefully, won't get to their 6th birthday. Keep an eye on the TPs.

Best.

RoadScholar · Apr 24, 2020

This post could go equally in one of the many threads about suspension.

Commonly available tires for Commandos are offered in "H" and "V" speed ratings. The "H" rated tires have a sidewalls which are not as stiff as their "V" rated siblings. Sidewall characteristics, considered as "springs", should be considered when selecting spring rates for your shocks/forks.

Best.

Bernhard · Apr 24, 2020

RoadScholar said:
This post could go equally in one of the many threads about suspension.

Commonly available tires for Commandos are offered in "H" and "V" speed ratings. The "H" rated tires have a sidewalls which are not as stiff as their "V" rated siblings. Sidewall characteristics, considered as "springs", should be considered when selecting spring rates for your shocks/forks.

Best.

Do Maxton consider this when you buy their shocks off them?

RoadScholar · Apr 24, 2020

Bernhard said:
Do Maxton consider this when you buy their shocks off them?

I'd be very surprised if they even asked. The differences approach the term "subtle"; much less so if, for example, you changed out the "S" rated tires on your grocery-getter for a set of "H"s or, for adventures in wasting money, a set of "W"s. Just something to think about when purchasing a set of new sneakers for your Commando.

Best.

Dunlop K81 “5817” Tire Date Code?

Slammin

L.A.B.

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Slammin

cyclegeezer

Slammin

L.A.B.

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Slammin

Tornado

L.A.B.

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Slammin

RoadScholar

RoadScholar

Bernhard

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