Speedo gear 32 vs 31 tooth
#2679829
07/21/19 06:35 PM
07/21/19 06:35 PM
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Joined: Jan 2003
Posts: 20,892 A collage of whims
topside
OP
Too Many Posts
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OP
Too Many Posts
Joined: Jan 2003
Posts: 20,892
A collage of whims
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According to Brewer's, I need a 31 tooth for 3.23s & 28" tire According to the Interweb, a 32-tooth. I have a mint 32, a mint 39, and a used 31 with a few teeth knocked off, of course What's 1 tooth worth in MPH on this setup? FWIW, I tend to drive by the tach on the highway, but around town I'd like to know my speed.
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Re: Speedo gear 32 vs 31 tooth
[Re: topside]
#2679834
07/21/19 06:50 PM
07/21/19 06:50 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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I'd want the mint 32 toother in there just cuz how bad the 31 toother is but it'd show the MPH a hair low than actual MPH (might cost you a ticket, might not). The archives has a chart & someone posted a link for a comprehensive chart but I dont have that info. EDIT measure your actual tire dia to get it as dead on as possible (might change what tooth count you need). MORE EDIT the chart someone posted had a MPH/RPM chart that was very helpful & there was something about an Excel worksheet. EVEN MORE EDIT the Excel worksheet in the 2 links are right there on the same page, right in front of me, I missed it.
Last edited by RapidRobert; 07/21/19 07:51 PM.
live every 24 hour block of time like it's your last day on earth
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Re: Speedo gear 32 vs 31 tooth
[Re: topside]
#2679974
07/22/19 04:57 AM
07/22/19 04:57 AM
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Joined: Aug 2007
Posts: 6,098 Valencia, España
NachoRT74
master
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master
Joined: Aug 2007
Posts: 6,098
Valencia, España
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There is an XLS table on tech section here where makes the exact maths. You could get maybe a 31,45 result. So you decide which one is the best for you based on that ( rounding up or not )
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: Speedo gear 32 vs 31 tooth
[Re: Mr340]
#2680033
07/22/19 10:14 AM
07/22/19 10:14 AM
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Joined: May 2003
Posts: 6,569 Downtown Roebuck Ont
Twostick
Still wishing...
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Still wishing...
Joined: May 2003
Posts: 6,569
Downtown Roebuck Ont
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I recently went from a 28 to a 29 and the speedo went from 4mph low to 3mph high. this was with a 2.76 and 26" tires and a 4 speed. Maybe go up a tire size or 2 to get it dead nuts. Kevin
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Re: Speedo gear 32 vs 31 tooth
[Re: Twostick]
#2680035
07/22/19 10:19 AM
07/22/19 10:19 AM
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Joined: Jan 2003
Posts: 1,009 Richmond Twp. Mi.
Mr340
super stock
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super stock
Joined: Jan 2003
Posts: 1,009
Richmond Twp. Mi.
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I recently went from a 28 to a 29 and the speedo went from 4mph low to 3mph high. this was with a 2.76 and 26" tires and a 4 speed. Maybe go up a tire size or 2 to get it dead nuts. Kevin I usually drive 5-7 over so the 3 hi gives me an extra cushion
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Re: Speedo gear 32 vs 31 tooth
[Re: topside]
#2680039
07/22/19 10:30 AM
07/22/19 10:30 AM
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Joined: Nov 2003
Posts: 10,228 Colleyville
3hundred
I Live Here
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I Live Here
Joined: Nov 2003
Posts: 10,228
Colleyville
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IIRC, when I did the arithmetic years and years ago, each tooth was worth ~ 1.67%. Which meant you should be able to get it within 1% either way +/- if your speedo head is working correctly. FWIW, YMMV, ect. 2¢
Roibert
'68 Fury Convertible '69 300 Convertible '15 Durango 5.7 Hemi '16 300 S Hemi
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