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Re: ACCURATE SPEEDOMETER?
Tracie wrote:
> Hello all. I have a 2006 Wrangler X with 6 speed manual tranny, 3.07 > gearing, and D30 front/35 rear. I recently upgraded my tires from the > stock 215/75/15 to 31/10.5/15 BFG All Terrain T/A KO. I am looking > for a reliable way to tell if my speedometer is off at all with the > tire upgrade. I do not have access to a GPS system. What I HAVE done > is to use the tripometer (with tenths), and hold steady at 60 mph (my > speedometer said 60) for one mile while watching my clock. I am > EXTREMELY close to going 1 mile in 1 minute by using this method. Is > this reliable to tell whether or not my speedometer is dead on? I > have NOT changed the speedometer gear yet, or had the computer changed > to reflect the larger sized tires. Also, I am not using my OD (6th) > much on the highway, but when I get up to 65 (the speedometer says > 65), I am running at about 2500 rpms in 5th. Is this bad, or should I > be shifting into the OD (6th)? I do fine with 1st through 5th. Just > not sure what speed or what rpms I should be using 6th. Any help is > really appreciated. > The (ones that have posed here) older TJ speedometers became correct when 31" tire were put on. Your mile per minute is a good base to tell it is close. The only other way is to find a measured mile or a friend with a GPS or even ask a cop to pace you because 'you just got new tires and don't want to break the law'. Only a cop's speedometer would be reliable for this, cars can be off too according to tire size. I find 'my' engine 'much' prefers to be running at 2300-2500 rpm on the highway which I get with my 4th gear. (have 33's and 3.31 gears) That rpm gives me good throttle control and prevents engine lugging. I also get a pretty stable 11L/100km or 23 mpg running there. If I go to overdrive or 5th gear, the rpm drops to 1750 or so at 65 mph which makes for the need of the full gas pedal travel to adjust speed or hold a hill or wind vs a twitch of the pedal in 4th. This low rpm drops my gas mileage by at least 5-8 mpg. You can find out easy. Just compare gas mileages when using only 5th on the highway and when using 6th mostly. I have one trip I do lots to get bush camping which is 201 km from gas station to gas station so I have an easy check point. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pi...?id=2115147590 (More Off Road album links at bottom of the view page) |
Re: ACCURATE SPEEDOMETER?
On Sep 17, 11:17 am, Mike Romain <roma...@sympatico.ca> wrote:
> Tracie wrote: > > Hello all. I have a 2006 Wrangler X with 6 speed manual tranny, 3.07 > > gearing, and D30 front/35 rear. I recently upgraded my tires from the > > stock 215/75/15 to 31/10.5/15 BFG All Terrain T/A KO. I am looking > > for a reliable way to tell if my speedometer is off at all with the > > tire upgrade. I do not have access to a GPS system. What I HAVE done > > is to use the tripometer (with tenths), and hold steady at 60 mph (my > > speedometer said 60) for one mile while watching my clock. I am > > EXTREMELY close to going 1 mile in 1 minute by using this method. Is > > this reliable to tell whether or not my speedometer is dead on? I > > have NOT changed the speedometer gear yet, or had the computer changed > > to reflect the larger sized tires. Also, I am not using my OD (6th) > > much on the highway, but when I get up to 65 (the speedometer says > > 65), I am running at about 2500 rpms in 5th. Is this bad, or should I > > be shifting into the OD (6th)? I do fine with 1st through 5th. Just > > not sure what speed or what rpms I should be using 6th. Any help is > > really appreciated. > > The (ones that have posed here) older TJ speedometers became correct > when 31" tire were put on. > > Your mile per minute is a good base to tell it is close. > > The only other way is to find a measured mile or a friend with a GPS or > even ask a cop to pace you because 'you just got new tires and don't > want to break the law'. Only a cop's speedometer would be reliable for > this, cars can be off too according to tire size. > > I find 'my' engine 'much' prefers to be running at 2300-2500 rpm on the > highway which I get with my 4th gear. (have 33's and 3.31 gears) That > rpm gives me good throttle control and prevents engine lugging. I also > get a pretty stable 11L/100km or 23 mpg running there. > > If I go to overdrive or 5th gear, the rpm drops to 1750 or so at 65 mph > which makes for the need of the full gas pedal travel to adjust speed or > hold a hill or wind vs a twitch of the pedal in 4th. This low rpm drops > my gas mileage by at least 5-8 mpg. > > You can find out easy. Just compare gas mileages when using only 5th on > the highway and when using 6th mostly. I have one trip I do lots to get > bush camping which is 201 km from gas station to gas station so I have > an easy check point. > > Mike > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > 88 Cherokee 235 BFG AT's - Gone to the rust pile... > Canadian Off Road Trips Photos: Non members can still view! > Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590 > (More Off Road album links at bottom of the view page)- Hide quoted text - > > - Show quoted text - So, assuming that my speedometer is correct, running approximately 2500 rpms in 5th gear at 65 mph will NOT hurt my engine or cause increased engine wear? If I were to shift into OD (6th), what is the approximate rpms that I should be running so as to not cause lugging or increased engine wear? THANKS |
Re: ACCURATE SPEEDOMETER?
On Sep 17, 11:17 am, Mike Romain <roma...@sympatico.ca> wrote:
> Tracie wrote: > > Hello all. I have a 2006 Wrangler X with 6 speed manual tranny, 3.07 > > gearing, and D30 front/35 rear. I recently upgraded my tires from the > > stock 215/75/15 to 31/10.5/15 BFG All Terrain T/A KO. I am looking > > for a reliable way to tell if my speedometer is off at all with the > > tire upgrade. I do not have access to a GPS system. What I HAVE done > > is to use the tripometer (with tenths), and hold steady at 60 mph (my > > speedometer said 60) for one mile while watching my clock. I am > > EXTREMELY close to going 1 mile in 1 minute by using this method. Is > > this reliable to tell whether or not my speedometer is dead on? I > > have NOT changed the speedometer gear yet, or had the computer changed > > to reflect the larger sized tires. Also, I am not using my OD (6th) > > much on the highway, but when I get up to 65 (the speedometer says > > 65), I am running at about 2500 rpms in 5th. Is this bad, or should I > > be shifting into the OD (6th)? I do fine with 1st through 5th. Just > > not sure what speed or what rpms I should be using 6th. Any help is > > really appreciated. > > The (ones that have posed here) older TJ speedometers became correct > when 31" tire were put on. > > Your mile per minute is a good base to tell it is close. > > The only other way is to find a measured mile or a friend with a GPS or > even ask a cop to pace you because 'you just got new tires and don't > want to break the law'. Only a cop's speedometer would be reliable for > this, cars can be off too according to tire size. > > I find 'my' engine 'much' prefers to be running at 2300-2500 rpm on the > highway which I get with my 4th gear. (have 33's and 3.31 gears) That > rpm gives me good throttle control and prevents engine lugging. I also > get a pretty stable 11L/100km or 23 mpg running there. > > If I go to overdrive or 5th gear, the rpm drops to 1750 or so at 65 mph > which makes for the need of the full gas pedal travel to adjust speed or > hold a hill or wind vs a twitch of the pedal in 4th. This low rpm drops > my gas mileage by at least 5-8 mpg. > > You can find out easy. Just compare gas mileages when using only 5th on > the highway and when using 6th mostly. I have one trip I do lots to get > bush camping which is 201 km from gas station to gas station so I have > an easy check point. > > Mike > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > 88 Cherokee 235 BFG AT's - Gone to the rust pile... > Canadian Off Road Trips Photos: Non members can still view! > Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590 > (More Off Road album links at bottom of the view page)- Hide quoted text - > > - Show quoted text - So, assuming that my speedometer is correct, running approximately 2500 rpms in 5th gear at 65 mph will NOT hurt my engine or cause increased engine wear? If I were to shift into OD (6th), what is the approximate rpms that I should be running so as to not cause lugging or increased engine wear? THANKS |
Re: ACCURATE SPEEDOMETER?
On Sep 17, 11:17 am, Mike Romain <roma...@sympatico.ca> wrote:
> Tracie wrote: > > Hello all. I have a 2006 Wrangler X with 6 speed manual tranny, 3.07 > > gearing, and D30 front/35 rear. I recently upgraded my tires from the > > stock 215/75/15 to 31/10.5/15 BFG All Terrain T/A KO. I am looking > > for a reliable way to tell if my speedometer is off at all with the > > tire upgrade. I do not have access to a GPS system. What I HAVE done > > is to use the tripometer (with tenths), and hold steady at 60 mph (my > > speedometer said 60) for one mile while watching my clock. I am > > EXTREMELY close to going 1 mile in 1 minute by using this method. Is > > this reliable to tell whether or not my speedometer is dead on? I > > have NOT changed the speedometer gear yet, or had the computer changed > > to reflect the larger sized tires. Also, I am not using my OD (6th) > > much on the highway, but when I get up to 65 (the speedometer says > > 65), I am running at about 2500 rpms in 5th. Is this bad, or should I > > be shifting into the OD (6th)? I do fine with 1st through 5th. Just > > not sure what speed or what rpms I should be using 6th. Any help is > > really appreciated. > > The (ones that have posed here) older TJ speedometers became correct > when 31" tire were put on. > > Your mile per minute is a good base to tell it is close. > > The only other way is to find a measured mile or a friend with a GPS or > even ask a cop to pace you because 'you just got new tires and don't > want to break the law'. Only a cop's speedometer would be reliable for > this, cars can be off too according to tire size. > > I find 'my' engine 'much' prefers to be running at 2300-2500 rpm on the > highway which I get with my 4th gear. (have 33's and 3.31 gears) That > rpm gives me good throttle control and prevents engine lugging. I also > get a pretty stable 11L/100km or 23 mpg running there. > > If I go to overdrive or 5th gear, the rpm drops to 1750 or so at 65 mph > which makes for the need of the full gas pedal travel to adjust speed or > hold a hill or wind vs a twitch of the pedal in 4th. This low rpm drops > my gas mileage by at least 5-8 mpg. > > You can find out easy. Just compare gas mileages when using only 5th on > the highway and when using 6th mostly. I have one trip I do lots to get > bush camping which is 201 km from gas station to gas station so I have > an easy check point. > > Mike > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > 88 Cherokee 235 BFG AT's - Gone to the rust pile... > Canadian Off Road Trips Photos: Non members can still view! > Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590 > (More Off Road album links at bottom of the view page)- Hide quoted text - > > - Show quoted text - So, assuming that my speedometer is correct, running approximately 2500 rpms in 5th gear at 65 mph will NOT hurt my engine or cause increased engine wear? If I were to shift into OD (6th), what is the approximate rpms that I should be running so as to not cause lugging or increased engine wear? THANKS |
Re: ACCURATE SPEEDOMETER?
On Sep 17, 11:17 am, Mike Romain <roma...@sympatico.ca> wrote:
> Tracie wrote: > > Hello all. I have a 2006 Wrangler X with 6 speed manual tranny, 3.07 > > gearing, and D30 front/35 rear. I recently upgraded my tires from the > > stock 215/75/15 to 31/10.5/15 BFG All Terrain T/A KO. I am looking > > for a reliable way to tell if my speedometer is off at all with the > > tire upgrade. I do not have access to a GPS system. What I HAVE done > > is to use the tripometer (with tenths), and hold steady at 60 mph (my > > speedometer said 60) for one mile while watching my clock. I am > > EXTREMELY close to going 1 mile in 1 minute by using this method. Is > > this reliable to tell whether or not my speedometer is dead on? I > > have NOT changed the speedometer gear yet, or had the computer changed > > to reflect the larger sized tires. Also, I am not using my OD (6th) > > much on the highway, but when I get up to 65 (the speedometer says > > 65), I am running at about 2500 rpms in 5th. Is this bad, or should I > > be shifting into the OD (6th)? I do fine with 1st through 5th. Just > > not sure what speed or what rpms I should be using 6th. Any help is > > really appreciated. > > The (ones that have posed here) older TJ speedometers became correct > when 31" tire were put on. > > Your mile per minute is a good base to tell it is close. > > The only other way is to find a measured mile or a friend with a GPS or > even ask a cop to pace you because 'you just got new tires and don't > want to break the law'. Only a cop's speedometer would be reliable for > this, cars can be off too according to tire size. > > I find 'my' engine 'much' prefers to be running at 2300-2500 rpm on the > highway which I get with my 4th gear. (have 33's and 3.31 gears) That > rpm gives me good throttle control and prevents engine lugging. I also > get a pretty stable 11L/100km or 23 mpg running there. > > If I go to overdrive or 5th gear, the rpm drops to 1750 or so at 65 mph > which makes for the need of the full gas pedal travel to adjust speed or > hold a hill or wind vs a twitch of the pedal in 4th. This low rpm drops > my gas mileage by at least 5-8 mpg. > > You can find out easy. Just compare gas mileages when using only 5th on > the highway and when using 6th mostly. I have one trip I do lots to get > bush camping which is 201 km from gas station to gas station so I have > an easy check point. > > Mike > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > 88 Cherokee 235 BFG AT's - Gone to the rust pile... > Canadian Off Road Trips Photos: Non members can still view! > Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590 > (More Off Road album links at bottom of the view page)- Hide quoted text - > > - Show quoted text - So, assuming that my speedometer is correct, running approximately 2500 rpms in 5th gear at 65 mph will NOT hurt my engine or cause increased engine wear? If I were to shift into OD (6th), what is the approximate rpms that I should be running so as to not cause lugging or increased engine wear? THANKS |
Re: ACCURATE SPEEDOMETER?
On Sep 17, 11:26 am, Tracie <brain...@upstate.edu> wrote:
> On Sep 17, 11:17 am, Mike Romain <roma...@sympatico.ca> wrote: > > > > > > > Tracie wrote: > > > Hello all. I have a 2006 Wrangler X with 6 speed manual tranny, 3.07 > > > gearing, and D30 front/35 rear. I recently upgraded my tires from the > > > stock 215/75/15 to 31/10.5/15 BFG All Terrain T/A KO. I am looking > > > for a reliable way to tell if my speedometer is off at all with the > > > tire upgrade. I do not have access to a GPS system. What I HAVE done > > > is to use the tripometer (with tenths), and hold steady at 60 mph (my > > > speedometer said 60) for one mile while watching my clock. I am > > > EXTREMELY close to going 1 mile in 1 minute by using this method. Is > > > this reliable to tell whether or not my speedometer is dead on? I > > > have NOT changed the speedometer gear yet, or had the computer changed > > > to reflect the larger sized tires. Also, I am not using my OD (6th) > > > much on the highway, but when I get up to 65 (the speedometer says > > > 65), I am running at about 2500 rpms in 5th. Is this bad, or should I > > > be shifting into the OD (6th)? I do fine with 1st through 5th. Just > > > not sure what speed or what rpms I should be using 6th. Any help is > > > really appreciated. > > > The (ones that have posed here) older TJ speedometers became correct > > when 31" tire were put on. > > > Your mile per minute is a good base to tell it is close. > > > The only other way is to find a measured mile or a friend with a GPS or > > even ask a cop to pace you because 'you just got new tires and don't > > want to break the law'. Only a cop's speedometer would be reliable for > > this, cars can be off too according to tire size. > > > I find 'my' engine 'much' prefers to be running at 2300-2500 rpm on the > > highway which I get with my 4th gear. (have 33's and 3.31 gears) That > > rpm gives me good throttle control and prevents engine lugging. I also > > get a pretty stable 11L/100km or 23 mpg running there. > > > If I go to overdrive or 5th gear, the rpm drops to 1750 or so at 65 mph > > which makes for the need of the full gas pedal travel to adjust speed or > > hold a hill or wind vs a twitch of the pedal in 4th. This low rpm drops > > my gas mileage by at least 5-8 mpg. > > > You can find out easy. Just compare gas mileages when using only 5th on > > the highway and when using 6th mostly. I have one trip I do lots to get > > bush camping which is 201 km from gas station to gas station so I have > > an easy check point. > > > Mike > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > > 88 Cherokee 235 BFG AT's - Gone to the rust pile... > > Canadian Off Road Trips Photos: Non members can still view! > > Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590 > > (More Off Road album links at bottom of the view page)- Hide quoted text - > > > - Show quoted text - > > So, assuming that my speedometer is correct, running approximately > 2500 rpms in 5th gear at 65 mph will NOT hurt my engine or cause > increased engine wear? If I were to shift into OD (6th), what is the > approximate rpms that I should be running so as to not cause lugging > or increased engine wear? > > THANKS- Hide quoted text - > > - Show quoted text - Oh, nevermind. I think I just answered my own question. : D I am assuming that the approximate 2500 rpms would apply to the OD (6th) gear as well to prevent increased engine wear and lugging? |
Re: ACCURATE SPEEDOMETER?
On Sep 17, 11:26 am, Tracie <brain...@upstate.edu> wrote:
> On Sep 17, 11:17 am, Mike Romain <roma...@sympatico.ca> wrote: > > > > > > > Tracie wrote: > > > Hello all. I have a 2006 Wrangler X with 6 speed manual tranny, 3.07 > > > gearing, and D30 front/35 rear. I recently upgraded my tires from the > > > stock 215/75/15 to 31/10.5/15 BFG All Terrain T/A KO. I am looking > > > for a reliable way to tell if my speedometer is off at all with the > > > tire upgrade. I do not have access to a GPS system. What I HAVE done > > > is to use the tripometer (with tenths), and hold steady at 60 mph (my > > > speedometer said 60) for one mile while watching my clock. I am > > > EXTREMELY close to going 1 mile in 1 minute by using this method. Is > > > this reliable to tell whether or not my speedometer is dead on? I > > > have NOT changed the speedometer gear yet, or had the computer changed > > > to reflect the larger sized tires. Also, I am not using my OD (6th) > > > much on the highway, but when I get up to 65 (the speedometer says > > > 65), I am running at about 2500 rpms in 5th. Is this bad, or should I > > > be shifting into the OD (6th)? I do fine with 1st through 5th. Just > > > not sure what speed or what rpms I should be using 6th. Any help is > > > really appreciated. > > > The (ones that have posed here) older TJ speedometers became correct > > when 31" tire were put on. > > > Your mile per minute is a good base to tell it is close. > > > The only other way is to find a measured mile or a friend with a GPS or > > even ask a cop to pace you because 'you just got new tires and don't > > want to break the law'. Only a cop's speedometer would be reliable for > > this, cars can be off too according to tire size. > > > I find 'my' engine 'much' prefers to be running at 2300-2500 rpm on the > > highway which I get with my 4th gear. (have 33's and 3.31 gears) That > > rpm gives me good throttle control and prevents engine lugging. I also > > get a pretty stable 11L/100km or 23 mpg running there. > > > If I go to overdrive or 5th gear, the rpm drops to 1750 or so at 65 mph > > which makes for the need of the full gas pedal travel to adjust speed or > > hold a hill or wind vs a twitch of the pedal in 4th. This low rpm drops > > my gas mileage by at least 5-8 mpg. > > > You can find out easy. Just compare gas mileages when using only 5th on > > the highway and when using 6th mostly. I have one trip I do lots to get > > bush camping which is 201 km from gas station to gas station so I have > > an easy check point. > > > Mike > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > > 88 Cherokee 235 BFG AT's - Gone to the rust pile... > > Canadian Off Road Trips Photos: Non members can still view! > > Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590 > > (More Off Road album links at bottom of the view page)- Hide quoted text - > > > - Show quoted text - > > So, assuming that my speedometer is correct, running approximately > 2500 rpms in 5th gear at 65 mph will NOT hurt my engine or cause > increased engine wear? If I were to shift into OD (6th), what is the > approximate rpms that I should be running so as to not cause lugging > or increased engine wear? > > THANKS- Hide quoted text - > > - Show quoted text - Oh, nevermind. I think I just answered my own question. : D I am assuming that the approximate 2500 rpms would apply to the OD (6th) gear as well to prevent increased engine wear and lugging? |
Re: ACCURATE SPEEDOMETER?
On Sep 17, 11:26 am, Tracie <brain...@upstate.edu> wrote:
> On Sep 17, 11:17 am, Mike Romain <roma...@sympatico.ca> wrote: > > > > > > > Tracie wrote: > > > Hello all. I have a 2006 Wrangler X with 6 speed manual tranny, 3.07 > > > gearing, and D30 front/35 rear. I recently upgraded my tires from the > > > stock 215/75/15 to 31/10.5/15 BFG All Terrain T/A KO. I am looking > > > for a reliable way to tell if my speedometer is off at all with the > > > tire upgrade. I do not have access to a GPS system. What I HAVE done > > > is to use the tripometer (with tenths), and hold steady at 60 mph (my > > > speedometer said 60) for one mile while watching my clock. I am > > > EXTREMELY close to going 1 mile in 1 minute by using this method. Is > > > this reliable to tell whether or not my speedometer is dead on? I > > > have NOT changed the speedometer gear yet, or had the computer changed > > > to reflect the larger sized tires. Also, I am not using my OD (6th) > > > much on the highway, but when I get up to 65 (the speedometer says > > > 65), I am running at about 2500 rpms in 5th. Is this bad, or should I > > > be shifting into the OD (6th)? I do fine with 1st through 5th. Just > > > not sure what speed or what rpms I should be using 6th. Any help is > > > really appreciated. > > > The (ones that have posed here) older TJ speedometers became correct > > when 31" tire were put on. > > > Your mile per minute is a good base to tell it is close. > > > The only other way is to find a measured mile or a friend with a GPS or > > even ask a cop to pace you because 'you just got new tires and don't > > want to break the law'. Only a cop's speedometer would be reliable for > > this, cars can be off too according to tire size. > > > I find 'my' engine 'much' prefers to be running at 2300-2500 rpm on the > > highway which I get with my 4th gear. (have 33's and 3.31 gears) That > > rpm gives me good throttle control and prevents engine lugging. I also > > get a pretty stable 11L/100km or 23 mpg running there. > > > If I go to overdrive or 5th gear, the rpm drops to 1750 or so at 65 mph > > which makes for the need of the full gas pedal travel to adjust speed or > > hold a hill or wind vs a twitch of the pedal in 4th. This low rpm drops > > my gas mileage by at least 5-8 mpg. > > > You can find out easy. Just compare gas mileages when using only 5th on > > the highway and when using 6th mostly. I have one trip I do lots to get > > bush camping which is 201 km from gas station to gas station so I have > > an easy check point. > > > Mike > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > > 88 Cherokee 235 BFG AT's - Gone to the rust pile... > > Canadian Off Road Trips Photos: Non members can still view! > > Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590 > > (More Off Road album links at bottom of the view page)- Hide quoted text - > > > - Show quoted text - > > So, assuming that my speedometer is correct, running approximately > 2500 rpms in 5th gear at 65 mph will NOT hurt my engine or cause > increased engine wear? If I were to shift into OD (6th), what is the > approximate rpms that I should be running so as to not cause lugging > or increased engine wear? > > THANKS- Hide quoted text - > > - Show quoted text - Oh, nevermind. I think I just answered my own question. : D I am assuming that the approximate 2500 rpms would apply to the OD (6th) gear as well to prevent increased engine wear and lugging? |
Re: ACCURATE SPEEDOMETER?
On Sep 17, 11:26 am, Tracie <brain...@upstate.edu> wrote:
> On Sep 17, 11:17 am, Mike Romain <roma...@sympatico.ca> wrote: > > > > > > > Tracie wrote: > > > Hello all. I have a 2006 Wrangler X with 6 speed manual tranny, 3.07 > > > gearing, and D30 front/35 rear. I recently upgraded my tires from the > > > stock 215/75/15 to 31/10.5/15 BFG All Terrain T/A KO. I am looking > > > for a reliable way to tell if my speedometer is off at all with the > > > tire upgrade. I do not have access to a GPS system. What I HAVE done > > > is to use the tripometer (with tenths), and hold steady at 60 mph (my > > > speedometer said 60) for one mile while watching my clock. I am > > > EXTREMELY close to going 1 mile in 1 minute by using this method. Is > > > this reliable to tell whether or not my speedometer is dead on? I > > > have NOT changed the speedometer gear yet, or had the computer changed > > > to reflect the larger sized tires. Also, I am not using my OD (6th) > > > much on the highway, but when I get up to 65 (the speedometer says > > > 65), I am running at about 2500 rpms in 5th. Is this bad, or should I > > > be shifting into the OD (6th)? I do fine with 1st through 5th. Just > > > not sure what speed or what rpms I should be using 6th. Any help is > > > really appreciated. > > > The (ones that have posed here) older TJ speedometers became correct > > when 31" tire were put on. > > > Your mile per minute is a good base to tell it is close. > > > The only other way is to find a measured mile or a friend with a GPS or > > even ask a cop to pace you because 'you just got new tires and don't > > want to break the law'. Only a cop's speedometer would be reliable for > > this, cars can be off too according to tire size. > > > I find 'my' engine 'much' prefers to be running at 2300-2500 rpm on the > > highway which I get with my 4th gear. (have 33's and 3.31 gears) That > > rpm gives me good throttle control and prevents engine lugging. I also > > get a pretty stable 11L/100km or 23 mpg running there. > > > If I go to overdrive or 5th gear, the rpm drops to 1750 or so at 65 mph > > which makes for the need of the full gas pedal travel to adjust speed or > > hold a hill or wind vs a twitch of the pedal in 4th. This low rpm drops > > my gas mileage by at least 5-8 mpg. > > > You can find out easy. Just compare gas mileages when using only 5th on > > the highway and when using 6th mostly. I have one trip I do lots to get > > bush camping which is 201 km from gas station to gas station so I have > > an easy check point. > > > Mike > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > > 88 Cherokee 235 BFG AT's - Gone to the rust pile... > > Canadian Off Road Trips Photos: Non members can still view! > > Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590 > > (More Off Road album links at bottom of the view page)- Hide quoted text - > > > - Show quoted text - > > So, assuming that my speedometer is correct, running approximately > 2500 rpms in 5th gear at 65 mph will NOT hurt my engine or cause > increased engine wear? If I were to shift into OD (6th), what is the > approximate rpms that I should be running so as to not cause lugging > or increased engine wear? > > THANKS- Hide quoted text - > > - Show quoted text - Oh, nevermind. I think I just answered my own question. : D I am assuming that the approximate 2500 rpms would apply to the OD (6th) gear as well to prevent increased engine wear and lugging? |
Re: ACCURATE SPEEDOMETER?
On Sep 17, 11:34 am, Tracie <brain...@upstate.edu> wrote:
> On Sep 17, 11:26 am, Tracie <brain...@upstate.edu> wrote: > > > > > > > On Sep 17, 11:17 am, Mike Romain <roma...@sympatico.ca> wrote: > > > > Tracie wrote: > > > > Hello all. I have a 2006 Wrangler X with 6 speed manual tranny, 3.07 > > > > gearing, and D30 front/35 rear. I recently upgraded my tires from the > > > > stock 215/75/15 to 31/10.5/15 BFG All Terrain T/A KO. I am looking > > > > for a reliable way to tell if my speedometer is off at all with the > > > > tire upgrade. I do not have access to a GPS system. What I HAVE done > > > > is to use the tripometer (with tenths), and hold steady at 60 mph (my > > > > speedometer said 60) for one mile while watching my clock. I am > > > > EXTREMELY close to going 1 mile in 1 minute by using this method. Is > > > > this reliable to tell whether or not my speedometer is dead on? I > > > > have NOT changed the speedometer gear yet, or had the computer changed > > > > to reflect the larger sized tires. Also, I am not using my OD (6th) > > > > much on the highway, but when I get up to 65 (the speedometer says > > > > 65), I am running at about 2500 rpms in 5th. Is this bad, or should I > > > > be shifting into the OD (6th)? I do fine with 1st through 5th. Just > > > > not sure what speed or what rpms I should be using 6th. Any help is > > > > really appreciated. > > > > The (ones that have posed here) older TJ speedometers became correct > > > when 31" tire were put on. > > > > Your mile per minute is a good base to tell it is close. > > > > The only other way is to find a measured mile or a friend with a GPS or > > > even ask a cop to pace you because 'you just got new tires and don't > > > want to break the law'. Only a cop's speedometer would be reliable for > > > this, cars can be off too according to tire size. > > > > I find 'my' engine 'much' prefers to be running at 2300-2500 rpm on the > > > highway which I get with my 4th gear. (have 33's and 3.31 gears) That > > > rpm gives me good throttle control and prevents engine lugging. I also > > > get a pretty stable 11L/100km or 23 mpg running there. > > > > If I go to overdrive or 5th gear, the rpm drops to 1750 or so at 65 mph > > > which makes for the need of the full gas pedal travel to adjust speed or > > > hold a hill or wind vs a twitch of the pedal in 4th. This low rpm drops > > > my gas mileage by at least 5-8 mpg. > > > > You can find out easy. Just compare gas mileages when using only 5th on > > > the highway and when using 6th mostly. I have one trip I do lots to get > > > bush camping which is 201 km from gas station to gas station so I have > > > an easy check point. > > > > Mike > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > > > 88 Cherokee 235 BFG AT's - Gone to the rust pile... > > > Canadian Off Road Trips Photos: Non members can still view! > > > Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590 > > > (More Off Road album links at bottom of the view page)- Hide quoted text - > > > > - Show quoted text - > > > So, assuming that my speedometer is correct, running approximately > > 2500 rpms in 5th gear at 65 mph will NOT hurt my engine or cause > > increased engine wear? If I were to shift into OD (6th), what is the > > approximate rpms that I should be running so as to not cause lugging > > or increased engine wear? > > > THANKS- Hide quoted text - > > > - Show quoted text - > > Oh, nevermind. I think I just answered my own question. : D > > I am assuming that the approximate 2500 rpms would apply to the OD > (6th) gear as well to prevent increased engine wear and lugging?- Hide quoted text - > > - Show quoted text - Which would probably be somewhere in the neighborhood of 70-75 mph in 6th at approximately 2500 rpms. |
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