At indicated 72mph, actual speed is 63mph

[MagikDraggin]

What would I need to do to get the speedo reading a little closer to the actual speed? It is a 4sp 62 Hawk w/3.31 rear gearing and stock-sized wheels/tires.

Thanks
Karl

[52 Ragtop]

I think you need a pinion with 1 or maybe 2 more teeth. I had the same problem with my 52, but after plying with the pinion gears, I got it pretty close.

Jim

[sbca96]

Look at it this way ... its better than the other way around!

Tom

'63 Avanti, zinc plated drilled & slotted 03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, soon: 97 Z28 T-56 6-spd, Ported heads w/SST full flow valves, 'R3' 276 cam, Edelbrock AFB Carb, GM HEI distributor, 8.8mm plug wires

[skyway]

I think the "specs" section of the 59-64 shop manual has a table showing the correct speedo pinions for various drivetrains.

[bams50]

I don't know why, but it seems like every car I own or have owned from the 60s and older has an inaccurate speedometer![}]

My GPS shows MPH, so if I'm wondering I put that in... sure looks funny in a Lark wagon...[:I]

Robert (Bob) Andrews Owner- IoMT (Island of Misfit Toys!)
Parish, central NY 13131

[DEEPNHOCK]

The manual has the ratios of the gears listed.
Here's one way to figure it out.
Note your RPM (in 1:1 drive) at an indicated 60 mph on your GPS.
Then note the RPM at the car speedo 60 mph.
(Speedo's are usually calibrated so 1000 rpm 'cable speed' is 60 mph.)
Divide to get the percentage of change you need to make it right.
Remove your trans speedo gear and note the number.
Look up that part number and see what other part number the percentage of change you are looking for will be.
Since you are close, it will probably be only one or two part numbers up or down. And this will automatically correct any tire diameter changes too. Only fly in the ointment would be if there was a major rear end gear change that would take you out of the range of the trans shaft gear, but that's doubtful.
Hope the info helps.
Jeff[8D]

quote:Originally posted by MagikDraggin

What would I need to do to get the speedo reading a little closer to the actual speed? It is a 4sp 62 Hawk w/3.31 rear gearing and stock-sized wheels/tires.

Thanks
Karl

[curt]

MY 1955 with radial tires is off 5 mph. I adjust my reading in my head. Tires will maks a big change in spedo readings.

[Dick Steinkamp]

"At indicated 72mph, actual speed is 63mph"

Odometer is probably off by much the same. I think this might be a major reason for the "reported" unrealistically high fuel mileage by some Studebaker owners .

[53k]

quote:Originally posted by 52 Ragtop

I think you need a pinion with 1 or maybe 2 more teeth. I had the same problem with my 52, but after plying with the pinion gears, I got it pretty close.
Jim

Good answer. I had the opposite problem with my '64 Daytona convertible (Powershift, 3.31, 205x75x15s). I was going much faster than the speedometer was indicating. I pulled the pinion and found that it was a 22-tooth pinion. Prescribed pinion was a 20-tooth. Installing the 20-tooth put my speedometer pretty close.
When I switched my '64 Avanti to a 3.07 from a 3.73 (automatic, 225x75x15s), I changed the 22-tooth to a 19-tooth pinion. Result- my odometer was off .1 mile in a measured 10-mile stretch on the interstate and with the speedometer reading 60 mph, the car took 60 seconds to go a measured mile.


[img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/R-4.JPG[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/64L.JPG[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/64P.jpg[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/53K.jpg[/img=right]Paul Johnson
'53 Commander Starliner (since 1966)
'64 Daytona Wagonaire (original owner)
'64 Daytona Convertible (2006)
Museum R-4 engine

[MagikDraggin]

I haven't been ignoring you guys....just waiting until all the answers were in

Ok, in checking with a couple parts outlets, I find that nobody has pinion gears for a '62 Hawk.....plenty for '63-'64 though. Plus is it just me or is 24 to 52 bucks for one of these things just a tad bit outrageous?

Karl

[53k]

quote:Originally posted by MagikDraggin

I haven't been ignoring you guys....just waiting until all the answers were in
Ok, in checking with a couple parts outlets, I find that nobody has pinion gears for a '62 Hawk.....plenty for '63-'64 though. Plus is it just me or is 24 to 52 bucks for one of these things just a tad bit outrageous?

Outrageous? Probably. If you need it, you need it. I paid Jon Myer $32 for the 20-tooth pinion I just bought. I have three 22-tooth pinions- guess I ned to market them.


[img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/R-4.JPG[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/64L.JPG[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/64P.jpg[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/53K.jpg[/img=right]Paul Johnson
'53 Commander Starliner (since 1966)
'64 Daytona Wagonaire (original owner)
'64 Daytona Convertible (2006)
Museum R-4 engine

[sbca96]

There was a tech article I read years ago about using a brand X gear
on the Studebaker carrier. Anyone remember that? You just order the
correct number tooth, cut their plastic carrier, drill the right size
hole in it, and press it on the knurl.

Tom

[curt]

Dick, my spodo is reading 5 mph higher than actual speed. However, yesterday on the way home from Branson,MO. I clocked 40 miles on the interstate side posts. My odometer reads 2 miles per 100 low: odometer 98 miles and the interstste posts 100 miles.I never have encountered such a situation, one high and the other low. The spedo was checked by GPS. One can divide 3600 by the seconds it takes to travel one mile, this equals MPH. (3600/ seconds to do a mile = mph.)

[John Kirchhoff]

Curt's situation is the result of the odometer being gear driven with a direct connection to the tranny. The speedo needle is by magnetic attration and is controlled by spring resistance. Other than the input from the cable, the two have nothing to do with each other. If there's no way to resolve the drive gear problem, one can always disassemble the speedo and adjust the spring to provide more resistance. Doing so will lower the indicated speed. I did that on one of my bikes to correct a 10% error in speed. Incidently, the odometer was nearly 100% correct.

Karl, you may want to check the accuracy of the odometer first. If it's incorrect the same percentage as the speedo, then a different gear is in order. If the odometer is close to correct but the speedo off, then a spring adjustment is in order.

[MagikDraggin]

quote:Originally posted by John Kirchhoff


Karl, you may want to check the accuracy of the odometer first. If it's incorrect the same percentage as the speedo, then a different gear is in order. If the odometer is close to correct but the speedo off, then a spring adjustment is in order.

That's a good point. I will take the Stude for a spin later on this afternoon and check the odo's accuracy.

If a "spring adjustment" is on order.....how techically difficult is this for a numb-fingered old man with what seems to be an extra thumb on each hand that always gets in the way?

Interesting.....I just added an edit and it disappeared...strange.

Anyway, I wanted to ask why the parts suppliers show a pinion gear for 63 and 64 4 speed Hawks, but not for 62? I would think they'd all be the same?

Karl