Terry,
Nice pics. If we only could “crack” Dunlop’s original production coding system, then we would be able to better date these tyres.
Yours show the code: 7KA 26648 (5 digits). I recently found a similar Dunlop Roadspeed with code 3RA 104223 (6 digits). So their coding system was typically 1AB 012345. Have not been able to discover any logic in this regarding year, month or whatever…
Regards, Bob K.
Well,
I too have an original tyre. My car is a Dec '53 and it could be original to the car. We could assume it is, as it was the spare tyre.
So, We have:
Urs Book: 1GA 16411
Terry: 7KA 26648 - date?
Tadek: 7LA 02678 - Dec '53
Bob: 3RA 104223 - date
So, 1st digit is the month and 1st letter is te year?
Followed by serial no?
We need more tyres!! 
My tubes are different Terry though, I I think they re original, too.
Tadek
PS. Urs Book, p. 122, Vol 1
How are we doing re the freight on the tyres **[quote=“Terry_McGrath1, post:28, topic:369426, full:true”]
send me your email address and I will send photos freight will be the killer
regards terry
61 407797003
[/quote]
**? still waiting please . Godfrey
Godfrey, what are your markings on your tyres?
Tadek
My car 679187 was rolling on these when I towed it home in 1980.
We discussed these once before and I think we came to the conclusion that Schrader supplied the black valve stubs and Dunlop vulcanized them onto the red tubes.
the Dunlop Roadspeed tires I have posted pics from I purchased about 35 years ago from Harry Gibson one time holder c1951/52 of the Australian motor bike speed record on a Vincent at over 150 mile per hour.
He noted that the tires a set of 5 had come from his brother Wally Gibson the owner of Alloy 120 660004 from sept 1953 through to january 1956.
The alloy 120 had been used to set the state land speed record in 1951 at 117.65mph on a set of Dunlop race tires and was fitted with factory undertray and an aeroscreen as per the 1949 Jabekke car.
I am fairly sure that these tires relate to this 1953-56 ownership.
There were 5 but 2 were used on a small box trailer!
Dunlop tires and tubes the real McCoy straight out of 1950 - I hope!
Tires both sides have markings
Hi Tadek the tyres I have were …so I’m told… the last set available before they went obsolete… so are of comparatively recent manufacture… C 2010? I can certainly get images for you if you wish but don’t have any close at hand.
Terry,
The 6.70 - 15 X was a fairly common/popular size apparently and standard offering for certain Facel Vega models and optional on Mercedes 300SL. It was available in both STOP tread pattern as per yours, or SDS tread pattern, albeit not sure of the relative technical merits or marketing direction of these two standard Michelin X patterns. (In 6.00 - 16 X size for XKs, only in SDS pattern)
But as before the change to metric widths and introduction of mandatory R (for Radial) identification within the tyre-size happened about the same time, and maybe some overlap manufacturer to manufacturer or model tyre to model tyre, I have yet to find anything definitive, but have just now refound photo of a 6.70 R 15 Michelin X tyre that was apparently the original spare wheel/tyre in a Mercedes 300SL that were last made in 1963, although this tyre still not showing any SPEED is I am sure a little earlier, I am guessing 1962? (Tyre looks ‘as-new’ condition - I have several photos, this one also STOP pattern)
Tadek,
If your assumption is correct (1st figure is month, 1st letter is year code), then the coding system of Dunlop tyres could look like the table below. I’ve assumed that your tyre was made in 1953 (which would be a tyre made in July 1953 mounted on a car produced in December 1953, which makes sense). The letter A behind the year letter is present for all years. Don’t know its meaning. Could be a factory code or even an attempt to use the same system over multiple decades with B, C etc.
Following this coding system, Urs’ tyre would date from January 1949 (?), Terry’s tyre from July 1952 and my tyre from March 1958.
In this system I’ve skipped the letter I and O (I believe just like SU did, Roger Payne?). The coding system would have been started in 1943 (strange) and ended in 1965 (which could have been the beginning of the new international tyre date coding system, but I know Roger is specialist in this matter…
Just a first try. Comments invited!
Bob K.
Has any one contacted Dunlop ? I used to pass, every morning on my way to work, Fort Dunlop , their old Ho (now hotel and shops etc ).
Last night I sent them an email with the three codes and to my surprise someone phoned me this morning . Now make of this what you want . He would not put it in writing because he could be wrong and perhaps the codes had been reused and did’t want to send me his code list . He has worked in the business since 1985
7LA 02678 JUNE 1997
7KA 26648 JUNE 1976
3RA 104223 NOT FOUND
Probably doesn’t hep much ?
Jim
Not that I want to hijack this thread , but what do you know of Le MANS tyres ? There is no other branding on them .
Jim
I have seen these tires on XK’s I imported from the USA and have 3 here in good condition still
Jim,
Your contact at Dunlop was correct in his statement: “He would not put it in writing because he could be wrong” as we know one thing for sure: Dunlop did not produce any Roadspeed tyres in either 1976 nor 1997. Nevertheless really appreciate your initiative in contacting Dunlop but we should try and find one of their people with “access to the past”…
I also had the LeMans tyres on my car when it arrived from the USA. I can add to what Terry says that as far as I can see they are “re-covered” or “remoulds” or “re-threaded” or what ever you call them (but not newly made).
New LeMans tyres are now available again but the brand has been revived by Bridgestone and are Made in China. So it has nothing to do with the tyres we had under our Jaguars.
Bob K.
Bob, AS you say a first try, as indeed the use of dates and date codes in the manufacturing industry is quite common as a quality and stock control aid.
In the case of SU, when first writing a paper on SU Fuel Pumps I started to notice the alpha/numeric stamping and then set out to discover what it meant. So not a dissimilar situation with these Tyre Codes.
The SU situation was simpler, given much lower volumes that SU clearly deemed monthly accuracy to be sufficient. The 1 to 12 stamping denoting January to December months was simple enough, but the letter significance was quite a challenge. I started to think that maybe the letter did denote a YEAR, but getting reliable consistent proof with Fuel Pumps was most difficult and elusive with fuel pumps not easily seen in-situe, and if on the bench lost any credible association with its original/dateable installation, but I was able to get a start with fuel pumps reliably dismantled from known XKs and Mark saloons. But then moved onto looking at Carburetters, which were very readily seen/read in situ, and most seen in unrestored cars were reliably original to a car of known identity and thus date-of-manufacture (to monthly accuracy). The net result of a considerable amount of sightings and resercah - into hundreds - is what I consider to be totally accurate SU decoding as follows…
A = 1945 to H = 1952
I and J are skipped/ not used, and this is not unusual re possible confusion with the number 1.
K = 1953 to N = 1956
O is skipped/ not used - again commonly avoided due to confusion with the number 0
P = 1957 with some caveat given unresolved status with Q
Q is used, but at this stage I don’t believe it represents any date/year but has some other significance, thus my caution with P. (I do have theories, but no definitive conclusions)
R = 1958 to U = 1961 So we have now fully covered my initial main interest areas of XKs, and also my initial interest areas of H6 and H8 carburetters and LCS Fuel Pumps, but to continue on ……
V and W are not used.
X = 1962
Y and Z are not used.
We then start again, now being well into E-type and Mark 2 interest area with HD6 and HD8 carburetters, and the last of the LCS fuel pumps still used on Mark 2.
A = 1963 to G = 1969 so all now straight forward but with HD6 and HD8 useage now restricted to RHD cars, I am starting to see increasing gap (6 months +) between Carburetter date and E-type/420G/240/340 dom.
And I hate to say it, but I quickly cannot find any instances of having seen/recorded any H stamped SUs, although I am sure they will exist.
Now in all of that, and I have a HUGE library of SU original period technical literature, I have never found anything at all from SU describing this date code system which I suspect is only way I will discover for sure the significance of letter Q, and indeed if any impact (I suspect not) on letter P. But I did find one Service Instruction sheet that did indeed reference the stamped in letter X denoting 1962.
Having introduced all the above - back to your first effort with tyres.
I think you need to have a lot lot more sightings of tyres, that you can reliable associate a date with, preferably original equipment fitment, and with tyres being a regularly changed consumable good luck with that.
For example, I seriously doubt DUNLOP, or any other British manufacturing company, would have commenced an alpha-year code system with A = 1943. Certainly the war time British Ministry of Supply did require certain things to be dated that were to be supplied to them, when manufacturers were restricted/controlled on any private use supply, but all the examples I am aware of spells out the full date which I have seen examples of 1943, 1944, 1945 (on SNAIL Brand spanners for instance) and up to 1952 on THOR Copper hammers supplied for Defence workshops. But who knows, maybe your DUNLOP use of A = 1943 does align with SNAIL dated spanners first seen as with 1943. But at this stage, given SU experience, I would be also careful assuming use of all letters, albeit no rules saying Dunlop had to do same as SU.
Roger
Original equipment on Pontiacs?
Ok seriously, its an affiliate of Bridgestone.
WalMart and Tire Rack sell them.
http://www.lemanstire.com/
Thanks Roger for your extensive, sound and logical reply (as usual). Indeed, no more than a first effort. However, some corrections can be made already. If SU skipped the letter J and we do the same for Dunlop, then the first year is 1944 (like Jaguar, Dunlop may have started preparations for the post war period duirng the last years of the war) and Urs’ tyre coded 1GA 16411 is from 1950 (sounds better). The second conclusion is that the whole coding scheme is not impossible…
Absolutely agree that we need many more tyres to see whether there’s logic in the coding. So with Tadek I say: We need more tyres!!
Bob K.
I think we all agree, the stamping does surely represent something that can be decoded, and most probably revealing a date, but of unknown accuracy. LUCAS for instance initially dated things in a mm/yy format but later wanting more accuracy changed to a ww/yy (w=week) format. The easiest way to find out is if something can be found or provided by DUNLOP regarding their 1950s coding and I am sure if it could be accessed there has to be something archived. Even advice of the modern coding may give a clue.
Absolutely no reason why DUNLOP coding will owe anything at all to SU coding, and vice-versa, and there was no legislated requirements in the 1950s to give any clues.
But without something official - and as advised, still haven’t found anything from SU - its really a matter of getting as many sightings as possible, but really helps if sightings can be reliably dated. With SU, it was relatively easy with Carburetters, but near impossible (but not impossible) with fuel pumps - but even so to cover my 20 year span of interest has ended up with hundreds of sightings, albeit now I only target my ‘grey’ areas, as the rest I am happy with now.
Roger
Well, I for one, have learned lots, through this discussion: had NO idea date codes went that far back on tires.
