My speedo. is off

sport · 08-18-2007, 11:16 AM

on my 92 k1500 sport 5 speed the speedometer is off my 5 MPH. It shows 5 mph faster than i am going. What would cause this? The tires are the right size. The speedometer does not jump around its steady as a rock. Any ideas?

Thanks

PickUpGirl787 · 08-18-2007, 08:55 PM

**** i thought i was going to get some good pictures out of this one haha just kidding, but maybe you should change the heading or am I the only one with a dirty mind?

crabtruck · 08-19-2007, 04:55 AM

what does it show at zero/parked ?
when did this start ? does it always do it ?
have you done anything to the tranny while pursuing your 4wd prob?
what tire size? what gear? did the seller do any mods ?

sport · 08-19-2007, 07:01 AM

it shows a little below zero when parked.
it has been this way since i got it. Just bought it not to long ago.
i haven't done anything to my 4x4 problem yet.
tire size is 265/75/R16. I am not aware of the previous owner doning any mods.

crabtruck · 08-19-2007, 03:04 PM

so can tire smart guys say if changing from 205or 245 to 265 would give his 5mph diff ?

mrjohnwayne · 08-20-2007, 07:32 AM

hmmm.. I can't remember the factory tire size but those you have don't seem stock. I can't remember chevy ever running a 16 inch wheel on a 1/2 ton. I could be wrong but I think that is your problem.

Never mind. 4x4's did have 16 in wheels.

crabtruck · 08-20-2007, 03:37 PM

the 245/75r16 were stock on my k1500 when I got it (94) and I remember being surprised and a little unhappy because they cost so much more than the 15's at the time.

What I never keep straight is what tire size ratio change does to speedo

mrjohnwayne · 08-20-2007, 04:29 PM

if 245 was stock and your running 265's thats probably why it's off

245-75-16 has a circumference of 95.7 inches

265-75-16 has a circumference of 99.4 inches

According to the calculator I used it said that the tire will cause the speedo to be 3.9% slower meaning if you are traveling at 60MPH (on speedo) you are actually traveling 62.3 MPH

http://www.miata.net/garage/tirecalc.html

Here is what I used

crabtruck · 08-20-2007, 04:38 PM

Quote:

Originally Posted by sport

on my 92 k1500 sport 5 speed the speedometer is off my 5 MPH. It shows 5 mph faster than i am going. What would cause this? The tires are the right size.

Sounds close enough to be the winner Sport

sport · 08-20-2007, 08:37 PM

the sticker on my door says LT 265/75/R16 and thats whats on my truck.
my speedo says 60 but i am going 55.

08-18-2007, 11:16 AM	#1
sport Full Member Join Date: Jun 2007 Posts: 40	My speedo. is off on my 92 k1500 sport 5 speed the speedometer is off my 5 MPH. It shows 5 mph faster than i am going. What would cause this? The tires are the right size. The speedometer does not jump around its steady as a rock. Any ideas? Thanks

08-18-2007, 08:55 PM	#2
PickUpGirl787 Senior Member Join Date: Dec 2006 Location: Illinois Posts: 711	**** i thought i was going to get some good pictures out of this one haha just kidding, but maybe you should change the heading or am I the only one with a dirty mind? __________________ Ashley My first truck was a 1988 Chevy 1500 with the 305 My new truck is a 1997 GMC 1500 with the 350

08-20-2007, 07:32 AM	#6
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,789	hmmm.. I can't remember the factory tire size but those you have don't seem stock. I can't remember chevy ever running a 16 inch wheel on a 1/2 ton. I could be wrong but I think that is your problem. Never mind. 4x4's did have 16 in wheels. __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

08-20-2007, 04:29 PM	#8
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,789	if 245 was stock and your running 265's thats probably why it's off 245-75-16 has a circumference of 95.7 inches 265-75-16 has a circumference of 99.4 inches According to the calculator I used it said that the tire will cause the speedo to be 3.9% slower meaning if you are traveling at 60MPH (on speedo) you are actually traveling 62.3 MPH http://www.miata.net/garage/tirecalc.html Here is what I used __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

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08-19-2007, 04:55 AM	#3
crabtruck Senior Member Join Date: Jul 2007 Posts: 4,100	what does it show at zero/parked ? when did this start ? does it always do it ? have you done anything to the tranny while pursuing your 4wd prob? what tire size? what gear? did the seller do any mods ?

08-19-2007, 07:01 AM	#4
sport Full Member Join Date: Jun 2007 Posts: 40	it shows a little below zero when parked. it has been this way since i got it. Just bought it not to long ago. i haven't done anything to my 4x4 problem yet. tire size is 265/75/R16. I am not aware of the previous owner doning any mods.

08-19-2007, 03:04 PM	#5
crabtruck Senior Member Join Date: Jul 2007 Posts: 4,100	so can tire smart guys say if changing from 205or 245 to 265 would give his 5mph diff ?

08-20-2007, 03:37 PM	#7
crabtruck Senior Member Join Date: Jul 2007 Posts: 4,100	the 245/75r16 were stock on my k1500 when I got it (94) and I remember being surprised and a little unhappy because they cost so much more than the 15's at the time. What I never keep straight is what tire size ratio change does to speedo

08-20-2007, 08:37 PM	#10
sport Full Member Join Date: Jun 2007 Posts: 40	the sticker on my door says LT 265/75/R16 and thats whats on my truck. my speedo says 60 but i am going 55.

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