Speedometer gear question
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Posting Guru
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From: abilene kansas
Speedometer gear question
The speedometer in My '87 F250 is running 3 to 5 mph fast. Has brand new P245/75R16 tires. (stock size is LT235/85R16) What gear would I need to get, to correct this? I have a C6 trans.
Lead Driver
Joined: Aug 2006
Posts: 5,670
Likes: 12
From: Sand Lake, MI
Not enough to go on, would need to know the gear ratio and color/tooth count of gear in it now.
Example,
http://www.summitracing.com/parts/sd...FYxAMgod0zcAnQ
Just an example mind you, you'd need correct for model/trans/rear ratio etc to be sure to get the correct gear for your exact application. I just googled "ford speedo drive gear" that example came up.
Added C6 to that comes up, http://www.summitracing.com/parts/tci-881004/overview/
Thread Starter
|
Posting Guru
Joined: Dec 2012
Posts: 1,242
Likes: 1
From: abilene kansas
Not enough to go on, would need to know the gear ratio and color/tooth count of gear in it now.
Example,
http://www.summitracing.com/parts/sd...FYxAMgod0zcAnQ
Just an example mind you, you'd need correct for model/trans/rear ratio etc to be sure to get the correct gear for your exact application. I just googled "ford speedo drive gear" that example came up.
Added C6 to that comes up, http://www.summitracing.com/parts/tci-881004/overview/
Example,
http://www.summitracing.com/parts/sd...FYxAMgod0zcAnQ
Just an example mind you, you'd need correct for model/trans/rear ratio etc to be sure to get the correct gear for your exact application. I just googled "ford speedo drive gear" that example came up.
Added C6 to that comes up, http://www.summitracing.com/parts/tci-881004/overview/
I have no idea what color/tooth count drive gear is in the trans.
Lead Driver
Joined: Aug 2006
Posts: 5,670
Likes: 12
From: Sand Lake, MI
Take it out count them, order one that is the next size up, one that is little larger in diameter, has more teeth.
You state its 3 to 5 mph fast, so get one that is larger dia result in slowing the speedo down, the next size up from the one you have should do it only 3 to 5 off.
If it was reading the other way to slow for example, then you'd want to swap to a smaller dia drive gear, one with fewer teeth than the one you have in it now, that would speed the speedo up make it spin faster read higher.
Thread Starter
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Posting Guru
Joined: Dec 2012
Posts: 1,242
Likes: 1
From: abilene kansas
Still not enough to go on, don't know what gear it has now how many teeth.
Take it out count them, order one that is the next size up, one that is little larger in diameter, has more teeth.
You state its 3 to 5 mph fast, so get one that is larger dia result in slowing the speedo down, the next size up from the one you have should do it only 3 to 5 off.
If it was reading the other way to slow for example, then you'd want to swap to a smaller dia drive gear, one with fewer teeth than the one you have in it now, that would speed the speedo up make it spin faster read higher.
Take it out count them, order one that is the next size up, one that is little larger in diameter, has more teeth.
You state its 3 to 5 mph fast, so get one that is larger dia result in slowing the speedo down, the next size up from the one you have should do it only 3 to 5 off.
If it was reading the other way to slow for example, then you'd want to swap to a smaller dia drive gear, one with fewer teeth than the one you have in it now, that would speed the speedo up make it spin faster read higher.
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