Trans ratio.

Q

Quijote

Guest
This is a question to anyone who could answer this fella from sunny Spain -maybe Mr. Gallagher-
When cruising down at 60 mph in the tacho, this is 100 Kmh, I read in the radarinfo I am going 88 Kmh. My beloved beauty Sedanette Super 49 wear Silvertowns 7.60 x 15; then, the Coker factory sheet says that the overall diameter is less than 0,5 inch more if I swith to 8.00 or even 8.25. It seem the tyre symply gets fatter, but no higher: thus, it would be an innecesary waste of money (imported to Spain, Silvertowns goes Diamondtowns, yes).
Could my resplendent Sedanette have got lost in her long life the rear tranny couply and got installed another? Or, perhaps, were there different differential ratios? I can go 60-75 mph down here, but then the straight-8 sounds like an F-84 out of control. I LOVE that purr at around 55 mph.
Excuse my cathastrophic English, never been at academies.
Finally: Anyone up there know the whereabouts of the "Biker Glossary" (Paisano Publications Inc.)? Look for "Indian Motorcycle", and get stunned the explanation they give: "THE HAPPY RESULTS FROM CROSSING A BUICK WITH A SCHWINN".
 
1940-1949 series 40 and 50 ran the same base gears 49:11.

An 41:10 set seems to have been available for "economy"

There was also a 43:11 available for the series 70 with dynaflow
 
Quijote, it was very common for American cars up into the 1980s to register up to 10 % faster than they are really going. I think the marketing departments of the manufacturers demanded the optimism. Your 100 kph vs. 88 kph by radar (if the radar is accurate) is 14% optimistic, still within the range commonly designed in.

Here is how you can tell exactly what your spedometer is doing: Drive exactly 60 kph indicated over exactly 1 kph (I assume there are kilo markers on your highways)and make an exact timing by seconds. Let us assume that your 100 kph is truly 88 kph. It will take you 68 seconds to travel 1 kilo. Do the math this way: time it takes to travel 1 kilo in seconds divided into 60 seconds (.88 in our example) multiplied by 60 kph = true speed (52.8 kph in our example).

I just found out my '49 sedan is the other way for some reason: the spedometer reads slower than the car is traveling !
 
You can interchange rear axle pigs from 1940 up through 1955. If you want a highway gear, install a V8 Dynaflow unit. They are in the 3,3-3.5 range ,and will let you run with the best without winding the engine to death!
 
Just coming from my tiny workshop today, firing my e-window and found all the replies. It's the best reason to understand how the USA can be so great.
Thanks (a truckload) to everyone. Now I'll have, as usual, good times ahead (solutions at hand) and bad times too (refresh again old friendships in FL and CA, begin the bloody war with my Bank when appear spares, etc. etc.), but what's life w/out troubles?
I enjoy this window. Never been so.
Could be abuse if I'd look for help to find & buy THAT V8 Dynaflow rear axle pig? (Just by the way, great casualty we call it here pig head). Don't forget all of you're living in the Buick Heaven; but then, here in Spain, you say you've got a Buick and they think you have a strange race of Madagascar dog.
angry.gif
 
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