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Author Topic:   gear ratio
poorboy5792
Dirt Roller

Total posts: 17
posted May 23, 2004 07:21 PM  
how do you figure the gear in a rear end without tearing it down??? a ford nine inch!! any help would be appreciated!!!!!

iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted May 23, 2004 08:38 PM  
You will need two people to do this

Mark a spot on the driveshaft and mark a spot on a wheel rotate the wheel one full turn and count how many times that the driveshaft rotates and divide the two

thats the way we done it although it has been several years since we have had to

Okie11m
Dirt Freak

Total posts: 287
posted May 23, 2004 09:02 PM  
Just wondering, why do you divide by 2? If your ratio for example is 3.73 then your drive shaft should turn 3.73 revolutions to one revolution of the tire. Right?

bigcityracer
Dirt Freak

Total posts: 431
posted May 23, 2004 09:20 PM  
quote:
Originally posted by iowa_dirt_track_girl:
You will need two people to do this

Mark a spot on the driveshaft and mark a spot on a wheel rotate the wheel one full turn and count how many times that the driveshaft rotates and divide the two

thats the way we done it although it has been several years since we have had to



It's not divide by 2. It's divide it by the to sums. Which would be 3.73 divided by 1.
I don't know why you would divided it either.

[This message has been edited by bigcityracer (edited May 23, 2004).]

racer17j
Dirt Forum Champ
Total posts: 5390
posted May 23, 2004 09:45 PM  
I agree w racer I am a so so mechanic but I admit i`m not a pro and ask advice often
I had a local guy a (pro)do the axleshaft theory onmyride and he says a 2.41 had 2 weeks of rain so had lotsa time on my hands so I took cover off read the numbers actually I have a 2.58 so by turning ya might get close but chances are ya will be off-the gear lube probably could use a changein any how so to besure take the cover off and get the right ratio

------------------
racing is way too cool gave up golf for it
http://http://chasinracin.com/cgi-bin/showpage.pl?ID=on_my_6

iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted May 24, 2004 12:12 PM  
like I said it has been years since we have done that i couldnt remmember what you divided by i though it was two but I guess I was wrong

carolinafast
Dirt Full Roller

Total posts: 72
posted May 24, 2004 03:12 PM  
how does one pull the cover on a 9"?????

WesternAuto17
Dirt Forum Champ
Total posts: 569
posted May 24, 2004 03:34 PM  
Lets not forget that ol' poor boy's dealing with a 9 inch. In order to count the teeth, he'd have to tear the whole thing down including pulling the axles and brakes. I'm all for doing things right, but the quick and dirty way might be the smarter thing in this case.

0six
Dirt Full Roller

Total posts: 52
posted May 24, 2004 06:21 PM  
hey poorboy did you go and pull it out yet if so what is it
0 SIX
my cousin called me this morning and said someone had been messing with the car, he was woried to death (and i kept it going for a little while ) then i told him it was us

[This message has been edited by 0six (edited May 24, 2004).]

poorboy5792
Dirt Roller

Total posts: 17
posted May 24, 2004 06:55 PM  
hey o six it is a 279, so it will do know good!! i have it in my truck, but my housing is toast so, i may use the housing if its okay!!! so when are you goin to work on your car??

0six
Dirt Full Roller

Total posts: 52
posted May 24, 2004 08:04 PM  
it is ok if you use it just remember me later. im going to work on it tomorrow. i looked under it today and the LR spring fell out i forgot to put the chain back on. you gonna help me scale it out?

bigcityracer
Dirt Freak

Total posts: 431
posted May 24, 2004 09:46 PM  
If you want check with out taking apart, turn the tire 10 times and count the axle then divide by ten and that will be the correct ratio.

Better than gettiing all dirty. Then you have more time to check over the car.

poorboy5792
Dirt Roller

Total posts: 17
posted May 25, 2004 10:02 AM  
o six, ill help you scale it out!! where you gonna get the scales and when!!!!! i got to go by greggss this evening so call me at the house to nite!!!!!!

bigcityracer
Dirt Freak

Total posts: 431
posted May 25, 2004 03:30 PM  
quote:
Originally posted by ssanto06:
if you have an OPEN DIFF you need to hold one tire from moving and rotate the other... then you divide by 2... the reason for dividing by two is that if only one wheel is spinning on an open diff, it is actualy spinning twice as fast as it would if both were spinning (given a constant drive shaft speed).

With an open dif you need to turn the tire two full turns and what ever the driveshaft turns is your gear, no dividing.

-Sal



    

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