4.11
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Junior Member
Joined: Jan 2002
Posts: 19
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From: Ontario
4.11
I have &00-R4 and i just got 4.11 and a posi for free so iwas wondering what i was going to need to make to speedometer acurate right now i was 3.07 and 235 60 R15 tires thanks for any help
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Joined: Jan 2000
Posts: 20,981
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Unfortunately there's no combination of speedometer gears you can use to make the speedometer read correctly with a 4.11 rear. You'll have to find some kind of an external ratio adapter box.
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Joined: Jul 1999
Posts: 17,262
Likes: 168
From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
You'll have 4.10 not 4.11. 10 teeth on the pinion gear and 41 teeth on the ring gear make 4.10. It doesn't sound like much but if you're trying to get an accurate speedo then use the proper numbers.
As mentioned above, you'll have problems finding proper speedo gears. You should just take it to a speedo shop and have them make an external adaptor.
As mentioned above, you'll have problems finding proper speedo gears. You should just take it to a speedo shop and have them make an external adaptor.
Senior Member
Joined: May 2001
Posts: 745
Likes: 0
From: springfield,IL
Car: T/A / Grand Am
Engine: 383 SBC
Transmission: glide
Axle/Gears: 9" ford 5.67
Originally posted by Stephen 87 IROC
You'll have 4.10 not 4.11. 10 teeth on the pinion gear and 41 teeth on the ring gear make 4.10. It doesn't sound like much but if you're trying to get an accurate speedo then use the proper numbers.
As mentioned above, you'll have problems finding proper speedo gears. You should just take it to a speedo shop and have them make an external adaptor.
You'll have 4.10 not 4.11. 10 teeth on the pinion gear and 41 teeth on the ring gear make 4.10. It doesn't sound like much but if you're trying to get an accurate speedo then use the proper numbers.
As mentioned above, you'll have problems finding proper speedo gears. You should just take it to a speedo shop and have them make an external adaptor.
Last edited by cp87GTA; Jan 27, 2002 at 01:19 AM.
Moderator
Joined: Jul 1999
Posts: 17,262
Likes: 168
From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Must be a factory gear set. All the aftermarket gears I've seen for the 7.5" are 10/41
Supreme Member
Joined: Jul 1999
Posts: 3,479
Likes: 54
From: Calimesa, California, U.S.
If your tires are close to 27" in height, then the 15 tooth drive gear & the 45 tooth driven gear will get you very close without spending the $100.00+ to get a speedometer shop to put on the adapter to get it to read correctly. 2nd, the odd number pinion tooth count is the stronger of the two (4.10 = 41-10, 4.11 = 36-9). This is pretty well known with rear end expects. Check it out.
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