Speedo Accuracy

[Jim Yergin]

Bob,

Len Dawson (http://www.dpmotorparts.com/inventory_4_b.cfm) and Collectors Auto Supply (http://www.collectorsautosupply.com/search.htm) indicate they have some.

652846 (16 teeth)

652845 (19 teeth)

652848 (17 teeth)

652842 (18 teeth)

Jim Yergin

[BobT-47P15]

Thanks, Jim. Will check. Don't really know what I need.

Not sure how many teeth on a standard P15 transmission speedo

gear.

[Jim Yergin]

Bob,

You should be able to determine that by using the chart on Chet's site that I posted earlier. It is based on your rear axle ratio.

Jim

[Powerhouse]

NO 16 teeth gears left...in the world it seems.

[BobT-47P15]

And then, there are some who should stay far away from speedos.......

[busycoupe]

My speedometer reads about 10 % too fast. I finally figured out that it is not the speedometer at all, but rather the tires that are on the car are about 10% taller than stock. --- Check your tire diameter before messing with speedometer gears.

Dave

[mrspeedyt]

The speedo still read (past tense, pronounced "red")

So now my speedo reads (present tense, pronounced "reeds")

(I've been thinking of changing spellings, to clarify the pronounciation words like of "read" and "lead". Present tense will be "reead" and "leead" for the long "e" sound, not to be confused with the aquatic plant "reed" or the verb "to lead". Past tense for "read" will be "redd" not to be confused with the color "red". The metal "lead" will be "ledd", not to be confused with the past tense of "lead", which is "led".)

Stranger things have happened to the language.

sounds good to me. our language can be so confusing sometimes.

even on my prius the speedo is off (1 mph) and the big trucks i drive can be off too.....gps is the more reliable accurate speedo....if you have a good signal.

[Merle Coggins]

(I've been thinking of changing spellings, to clarify the pronounciation words like of "read" and "lead". Present tense will be "reead" and "leead" for the long "e" sound, not to be confused with the aquatic plant "reed" or the verb "to lead". Past tense for "read" will be "redd" not to be confused with the color "red". The metal "lead" will be "ledd", not to be confused with the past tense of "lead", which is "led".)

Stranger things have happened to the language.

I posted this here a while back... A little poem I've had around for a while.

"Our English Langauge"

We'll begin with a box, and the plural is boxes,

But the plural of ox should be oxen, not oxes.

Then one fowl is a goose, but two are called geese,

Yet the plural of moose should never be meese.

You may fine a lone mouse or a whole nest of mice,

But the plural of house is houses, not hice.

If the plural of man is always called men,

Why shouldn't the plural of pan be called pen?

If I speak of a foot and you show me your feet,

And I give you a boot, would a pair be called beet?

If one is a tooth, and a whole set are teeth,

Why shouldn't the plural of booth be called beeth?

If the singular's this and the plural is these,

Should the plural of kiss ever be nicked keese?

Then one may be that and three would be those,

Yet hat in the plural would never be hose,

And the plural of cat is cats and not cose.

We speak of brother, and also of brethern,

But though we say mother, we never say methern.

Then the masculine pronouns are he, his, and him,

but imagine the feminine she, shis, and shim.

So the English, I think, you all will agree,

Is the queerest language you ever did see.

-----------------------------------------

And one of my pet peeves is the missuse of "there", "their". and "they're". Although they are (they're) pronounced the same (for most of us) they have very different meanings.

"Their car is parked over there in the garage and they're planning to leave it there until they're ready to take it out for their weekly cruise."

Merle

Edited July 22, 2010 by Merle Coggins

[DonaldSmith]

"It's" means "It is." "Its" means "of or belonging to it.

"You're" means "You are." "Your" means "of or belonging to you."

On the other hand, don't be afraid to post away, missspelllings and all. We can figure out what you mean.

[Young Ed]

My speedo issue. Earlier this spring my odometer snapped and never moved again. Speedometer was very accurate before that. So I sent it off to be rebuilt. Got it back in the car and it read 15mph high across the board. Took it back sent it back and now it reads 15mph low but I didnt reinstall it I just hung it under the dash. So A) could installing it or not installing it make a difference? Whats wrong with it that it reads a set MPH high or low? C) what to do about the shop that can't get it right?

[Reg Evans]

Even my reading glasses don't help on this one.

Right click on Tim,s image and when it comes up right click on it again. Right click on it again and it blows it up to a readable size.

[P-12 Tommy]

Thanks Reg!

Tom

[windsor8]

The speedometer neeedle in my D24 would bounce about. On the work bench I used a little WD 40 to lube it for a few days and would trun it with a drill motor, it runs smoothly now.

[james curl]

The speedometer should read 60 MPH when turned at 1000 RPM. The speed is set while turning the shaft at 1000 RPM by tightening or loosening the hair spring until the needle reads 60 MPH. It is hard to find some one today who can calibrate a mechanical speedometer. They all seem to only do electronic speedometers.

[Merle Coggins]

What I find interesting is that my speedo is fairly accurate (within 5%) even after I switched my differential from a 4.10:1 to a 3.73:1. Since I didn't drive it before the swap I don't know how far off it was before, but it must have been. When I first got the truck together the speedo chattered badly and would peg the needle above 30 MPH. I lubed the speedo and the cable and it all settled down. However, now with the 3.73 gears and 235/75R-15 tires at just over 29", compared to the 7.50x15's at around 30", my GPS registers 68 when my speedo shows 65. That's close enough for me. I never touched the speedo gear in my trans.

Merle

[Reg Evans]

I use to bring my speedos into a shop here in town called Arches Automotive. Old Arch would hook the speedo up to a machine and zap it to get the magnetism just right. A few years after his passing I stopped in to have this done again but his son,about my age and not interested in old iron, got rid of that machine. That's progress I guess.