Speedometer Follow-up

[TR3BGeorge]

Hey Guys, I hope that you are enjoying the first day of spring. It is pouring rain here, so our club postponed our March Lunch drive to next Saturday. We will drive to a BBQ spot out in the country for lunch, then tour a cheese farm/factory. But, I digress.

 

As you know, I asked your advice on my speedo. My serial number is SN6319/00, with 1184 revolutions per mile. I purchased a clean speedo off ebay, with SN6307/04, 1180 numbers. Not to worry, as I figured that we could either cannibalize the new one's odometer or trip odometer gear, or replace the entire old speedo with the new one.

 

As the bar girls used to tell me in Japan, "Never happen, boy-san."

 

It turns out that the new speedo is about an inch deeper than the old one. As you probably know, the speedo is held to the dashboard with two knurled nuts and spade brackets that fit over two long threaded studs. Well, here is the rub. The two studs are different sizes, so the spades and nuts are not interchangeable. And, even if they were interchangeable, the two spades are not long enough to accommodate the deeper speedo body.

 

So, keep this in mind when/if you are speedo hunting.

 

Moving right along, I tested the new speedo on the car. The speed needle works perfectly, the trip odometer works perfectly (without the reset shaft/knob), but the odometer does not work. To recap, NEITHER of the odometers works on my car. So, here is what I have, since I cannot use the deeper speedo. If we can cannibalize the trip odometer gear out of the new speedo into my old one, then I am happy, as I can live with just a trip odomter. However,if we can NOT cannibalize the new one, I will continue looking, and will have learned a $30 lesson (15 for speedo, 15 for shipping).

 

Also, someone has contacted me about a new-in-box speedo that he has in France, that he will locate and make me an offer on. So, I am waiting to hear his price. Onward and upward, mes amis.

[TR 2100]

I could be wrong, but I thought the shallower speedos were as fitted

to later TRs, late 4/4A? Maybe someone will correct me.

If I'm right, then someone has already changed the original for a

later one.

 

If the needle and trip are working, the odometer should be working -

it's all the same drive.

Maybe someone has been messing about with the odometer display and

b******d up both of them?

 

AlanR

[Don Elliott]

Alan - I was driving my 1958 TR3A through Kansas on the way back home to Montreal -- back from the VTR event in Colorado in July 2001 when the main mileage counter stopped working. The needle and the trip odometer were still working. Then in September, I happened to be with my TR on business down in New Jersey and dropped my speedo off at Nisonger's just east of New York City for repair. That was about a week after 9-11 and I could still see all the smoke plumes after the twin towers events. They changed one gear wheel and said they recalibrated it for about $300.00. It has worked fine sincve then now but it's not calibrated for my 165 Vredestein tyres. At a true 70 MPH it reads 79 MPH.

[vivdownunder]

George, fatter speedos with domed glass were fitted to sidescreen cars - thinner speedos with domed glass to TR4's, and a different thin speedo with flat glass to TR4A's.

 

SN6307/04 with II80 wheel turns per mile is a sidescreen speedo for use with a 3:7.1 diff and 5.90x15 cross ply tyres. 1184 turn speedo's were for 3:7.1 diff and 6.95x15 cross ply tyres. Only a TR4 speedo was calibrated at 1152 turns for today's 165x15 radial tyres and a 3:7.1 diff.

 

3A speedos were mounted with a single U shaped bracket held by two round knurled nuts. The TR4 spade mounts must fit the 3A speedo though if you wind the knurled nuts down, as that's what I have.

 

It's unclear which speedo was originally fitted to TCF series TR3B's. It could have been a thinner TR4 one, if the fatter 3A ones ran out of stock. I've seen a note that the 3B dash was altered from the 3A, but have no details as to what that was. I searched for ages when I had the TR3B parked beside one of the 3A's, and couldn't see any difference. However I didn't think to look at the speedo serial/turn number.

 

Maybe John McIver, who now owns the 3B, will see this and post the speedo details.

 

Lovely Autumn Sunday here, and went to our premier show of vintage RR's, WO Bentleys, Lagonda's, Alvis etc. Cars grouped in marques parked around the perimeter of a mountain oval so "Sound of Music" that I nearly broke into a yodel.

 

Regards,

 

Viv.

[BrianC]

...it's not calibrated for my 165 Vredestein tyres. At a true 70 MPH it reads 79 MPH.

 

That's something I've never considered when fitting new tyres. At least your speedo over-reads, so no excuse for getting caught speeding. I wonder if it is a general rule that TR speedos, originally intended for use with cross-ply tyres, will over-read when 'standard' 80-profile radials are fitted?

[TR 2100]

At least your speedo over-reads, so no excuse for getting caught speeding.

I wonder if it is a general rule that TR speedos, originally intended for use

with cross-ply tyres, will over-read when 'standard' 80-profile radials are fitted?

 

Don't know about anyone else, but I have always kept an eye on my speed

by the rev counter. Far more accurate than the fluctuating speedo needle

that all my TRs have always had.

Obviously easier in top and overdrive top, but that's when it's most

important.

It's not so difficult to include 3rd and overdrive into this.

 

AlanR

Edited March 21, 2010 by TR 2100

[angelfj]

 

I nearly broke into a yodel.

 

 

This I would love to hear!!!

[Alec Pringle]

" I wonder if it is a general rule that TR speedos, originally intended for use with cross-ply tyres, will over-read when 'standard' 80-profile radials are fitted?"

 

It is indeed Brian . . . . the effective rolling radius of a 155 or even 165 80-profile radial is significantly smaller than that of a 5.50 let alone a 5.90 crossply. Tyre pressure and tread wear also influence effective rolling radius, albeit by a considerably smaller factor than the difference between crossply and radial fitment. The various speedo options available for the Michelotti cars covered at least some of the permutations, whereas the earlier sidescreen cars offered only two choices - 3.7 or 4.1 axle ratio . . . later 3A and 3B I'm not sure about, as in whether there were speedo variations available.

 

Cheers,

 

Alec

[TR3BGeorge]

Thanks again, guys. Some good poop. Viv, I am not surprised that I have a TR4 speedo. My car could be named "Eclectic," as it is a conglomeration of parts from the TR3A thru the TR-6. Of course, the Spare Parts Catalog is no help at all. However, good ol' Moss has an interesting item: they have the knurled nut for both a 4mm diameter stud and a 5mm diameter stud. Godhelpus. Also, they DO list a speedo for the 3.7:1 and the 4.1:1 ratios.

 

Your explanation of the tire (tyre) differences brought tears to my eyes. As Don or someone else mentioned, we all had best take our cars out - WITH A GPS - and get some accurate readings. My car came with huge 195/15 tires on it, so the first thing I did was take her out with my GPS and see what was what. 50 on the speedo was actually 60, and 60 on the speedo was actually 70. 40 is actually 45, so I have to be very careful around here, as most of the city/town speed limits are 40.

 

So, I am waiting on my club friend to show me how to work on speedos and waiting to hear from the chap with a new speedo in France.

 

Thanks again.

 

Epilog. Sometimes I just have to shake my head. Why in the world would Leyland switch from a 5mm stud to a 4mm stud, to hold a speedo and tach in? I remember the U-shaped bracket perfectly. It worked perfectly, something that could not be improved upon.

Edited March 22, 2010 by TR3BGeorge

[david ferry]

George,

 

This may be worth a look.

 

http://cgi.ebay.com/ebaymotors/NOS-Vintage-Smith-Jaeger-Triumph-TR2-TR3-Speedometer_W0QQcmdZViewItemQQhashZitem1e5afed327QQitemZ130375668519QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

Mine is still in France!

 

Regards

 

David