Cooper and 'S' shift marks on original speedos

[rdcoulthard]

I gather that Cooper and 'S' speedos were available from the factory set for 3.44, 3.76, and 3.94 diff ratios. Does anyone know if the yellow shift marks on the speedo placed to account for the diff ratios? I've looked at a fair number of photos of speedos, and aside from comparing 1071 S speedos to 1275 S speedos, the marks don't seem to be different for 3.76 vs. 3.44 at least.

[imack]

Mines got lower than standard shift marks.
I did check out the numbers on it at some point, I think it was for a 3.9 final drive.
I bought it in the mid 80's from Tim Harbour when he ran Metro and Mini spares in Putney, it was brand new in a British Leyland box.

[Spider]

There are quite a few models for the Cooper and Cooper S. I know these are calibrated for the various final drive ratios (and even SP41 Tyres) that were available as factory options, but until seeing Imack's Speedo, I wasn't sure if these had different shift points marked too.

[Stopped-again]

Here’s my Speedo, it’s a 4479/28A 1408tpm and the shift marks are higher than the Mk2 1472tpm shown in imack’s post.

[Peter Laidler]

That's a good question! I have a calibrated speedo (I got a couple of new/calibrated from Smiths who were nearby) in my Mk2 cop car, SN4421/44 - 1472 running a 3.4 f/d and Dunlops. It has the markers at 1=approx 37, 2= approx 53 and 3=approx 76, just like one of those shown.

Personally, I think that the markers are just that. A general across-the-board guide. Would it really matter where the markers were if............ I wonder how these 1275 S markers relate to 998 Cooper markers

Interesting

[imack]

Couple of pictures of S speedo currently on ebay. The shift point markings are in subtlety different positions, easier to spot if you compare the shift points with KPH markings.
Plus a better shot of mine (top pic) for 3.9 final drive.

[GraemeC]

I wouldn’t go off the kph markings, as it looks like the conversion maths between kph and mph is different for those last two photos!

[imack]

I wouldn’t go off the kph markings, as it looks like the conversion maths between kph and mph is different for those last two photos!

Well spotted, I hadn't noticed that!

[janerick3]

Here is a Mk 2 998 Cooper 170 km/h speedo, SN 4421/23 880 revs/km (3.76:1 final drive).

[1071 S]

If they went to the trouble of having different ID numbers for each variant and noting the correct numbers (turns per mile - or whatever) for each diff ratio why would they not mark the max revs (presumably the same for all of a particular engine type) correctly on each speedo variant??

What really bugs me is the I can't see the apparent variation between the mph/kph conversions on the two photos???

Cheers, Ian

[GraemeC]

What really bugs me is the I can't see the apparent variation between the mph/kph conversions on the two photos???

Cheers, Ian

Look at 70mph. On one it’s equal to 110 kph, on the other it’s about 113kph.
Also quite an obvious difference at 90mph and 110mph

[rdcoulthard]

Wow, some great photos there. Thanks everyone. For 997/998 Cooper with 3.76, both speedos I have have the 3rd shift point at about 64mph. Both my Coopers are running 3.44, but have re-calibrated 3.76 speedos (1408). I wonder if anyone out there has an actual 997 or 998 Cooper speedo factory set for the optional 3.44 diff ratio (1280)? A seller on eBay has the centre speedo ring for a 3.44 998 Mk2 Cooper set for 1280, but that's the closest I've ever seen to such a speedo.

https://www.ebay.ca/itm/Speedometer-Inn ... 3843559153

[bwaminispeed]

My mid 64 1275 S is marked 40, 60, and, 85 MPH, which is considerably more than all the previously posted ones.......

40 MPH in 1st gear on a probably .344 final drive, is squeezing it pretty tight.......

My .376 geared 61 850 hit valve float reliably at 28 mph, which, was the highest speed I could engage
first gear while downshifting on it's 3 synchro gearbox.......

[1071 S]

Hi Graeme,

Not really seeing it... I’ll allow there might be a slight misalignment (or parallax) between the two scales but to my eye both speedos show 90mph = (pretty much) 145 kph while 110mph= 180kph.

The best places to compare are 50 and 100 mph which equate to exactly 80 and 160 respectively.

I use a S speedo calibrated for a 3.76 diff in my car that now has a 3.1 diff .. in a world signposted in kilometres. You get used to it quite quickly. While speedos are easily recalibrated (or at least they were before our local expert retired odos are more of a problem. But even so, 3.1 differs from 3.44 by about 10% so if you add 10% to the indicated speed and distance you’re not far out.

Cheers, Ian

[rdcoulthard]

This is the (unusual) Speedo in the 1962 997 Cooper my father and I restored in 2018. SN6404/02 and 1408 tpm with a trip odo! Shift marks at 28mph, 45mph and 63mph.

[Cammsjb]

MK2 S speedometer SN-4421/32-------1280 gear shift markings.

MK 2 S speedo.jpeg

[mnicoop63]

I have a handful of speedos and you guys have me curious with this post so I dug out a few. One is a Cooper 997 !00mph speedo SN4479/06 1408rpm. 5/62 thru 9/64. It has shift points at 27/28mph, 46mph, and 65mph. Another is a 998 Cooper 105mph speedo SN4417/44 1408rpm with optional Dunlop SP41 tires. 5/65 on.. The shift marks for it are pretty much identical to that of the 997 speedo. I have another 105mph 998 Cooper speedo but it's not here at the house. I am curious what the marks are on it. I also have a Cooper S "1000" Speedo SN4417/18a 1280rpm. for the 3.44 diff. 10/64-65. It's shift points are at 32mph, 53mph and 78mph.

Here is the link to the Smiths Speedometer Serial Numbers for pretty much all MK1 minis and variants from the MK1-Performance site.

http://mk1-performance-conversions.co.u ... umbers.pdf

Brian

I have no idea why the last two uploaded sideways.

[Peter Laidler]

It's a shame that the Smith Tech Dept aren't still based at Witney and that I don't have a tech parts list for the speedo's. Given the variations of the Cooper and S speedo's alone, the permutations between he INNER face and the OUTER face, the final speed, revolutions per mile number, final drive, intermediate ratios, gear change points and probably several other permutations, the amount of theoretically available combinations for Cooper and S speeeo's will run into over 500 AT LEAST (and I got fed up number crunching). That is a rough estimate using the info available from 3 parts lists and the Smiths handbook on our own tech info pages. Mind numbing or what!!

You never know........, this speedo identification trait could soon replace the '.....its's not an S because it hasn't got twin tanks.....' or the other old favourite '.....I had one of these new from the factory in Briitish Racing Green....'. Imagine Beaulieu with a speedo expert walking around telling the flock that '..... your speedo head is wrongly marked for the car'!