Another Re-gear question
12-26-2018, 04:12 PM
#1
Another Re-gear question
Hey everyone,
So background- I have a 2018 3.5EB with 3.31's with electronic locker. I added a 2" level and 275/65-20 BFG K02's which are about 34" tall. I enjoyed the acceleration when I first bought the truck, as I think the taller gears allowed me to get into boost sooner. But after adding the tires, the truck has been annoying to drive. It has to downshift way more often, and generally feels sluggish. I find myself driving in tow/haul mode and sport mode more often to keep the RPM higher, and lessen the downshifting.
The truck is mostly driven by my wife, but I drive it on weekends. I would say its a 50/50 mix of highway and city driving. I tow with it occasionally- probably 12-20 times a year, and tow heavy when I do.
So I want to regear the truck, but am a bit torn at what I should do. 3.73's would be a good mix it seems for when I am not towing, but I am sure 4.10's would be appreciated when I am. According to stage3 motorsports Instagram post, the jump from 3.31 to 3.73 would be 270rpm at whatever they figure for highway speed, and the jump from 3.31 to 4.10 would be 520rpm. Does anyone know if this chart is applicable to the new 10speed?
Ideally, somebody would have a ration of like 3.90 to split the difference. I feel like 4.10's might be too much when not towing but 3.73's might have me wishing for more when I am towing. What would you go with? Also, I know with the ecoboost the 4.10's would not be in boost as much as the 3.73's so would it be about equal as far as MPG goes? I currently get 16mpg with 3.31's.
So background- I have a 2018 3.5EB with 3.31's with electronic locker. I added a 2" level and 275/65-20 BFG K02's which are about 34" tall. I enjoyed the acceleration when I first bought the truck, as I think the taller gears allowed me to get into boost sooner. But after adding the tires, the truck has been annoying to drive. It has to downshift way more often, and generally feels sluggish. I find myself driving in tow/haul mode and sport mode more often to keep the RPM higher, and lessen the downshifting.
The truck is mostly driven by my wife, but I drive it on weekends. I would say its a 50/50 mix of highway and city driving. I tow with it occasionally- probably 12-20 times a year, and tow heavy when I do.
So I want to regear the truck, but am a bit torn at what I should do. 3.73's would be a good mix it seems for when I am not towing, but I am sure 4.10's would be appreciated when I am. According to stage3 motorsports Instagram post, the jump from 3.31 to 3.73 would be 270rpm at whatever they figure for highway speed, and the jump from 3.31 to 4.10 would be 520rpm. Does anyone know if this chart is applicable to the new 10speed?
Ideally, somebody would have a ration of like 3.90 to split the difference. I feel like 4.10's might be too much when not towing but 3.73's might have me wishing for more when I am towing. What would you go with? Also, I know with the ecoboost the 4.10's would not be in boost as much as the 3.73's so would it be about equal as far as MPG goes? I currently get 16mpg with 3.31's.
12-26-2018, 06:01 PM
#2
Hey everyone,
So background- I have a 2018 3.5EB with 3.31's with electronic locker. I added a 2" level and 275/65-20 BFG K02's which are about 34" tall. I enjoyed the acceleration when I first bought the truck, as I think the taller gears allowed me to get into boost sooner. But after adding the tires, the truck has been annoying to drive. It has to downshift way more often, and generally feels sluggish. I find myself driving in tow/haul mode and sport mode more often to keep the RPM higher, and lessen the downshifting.
The truck is mostly driven by my wife, but I drive it on weekends. I would say its a 50/50 mix of highway and city driving. I tow with it occasionally- probably 12-20 times a year, and tow heavy when I do.
So I want to regear the truck, but am a bit torn at what I should do. 3.73's would be a good mix it seems for when I am not towing, but I am sure 4.10's would be appreciated when I am. According to stage3 motorsports Instagram post, the jump from 3.31 to 3.73 would be 270rpm at whatever they figure for highway speed, and the jump from 3.31 to 4.10 would be 520rpm. Does anyone know if this chart is applicable to the new 10speed?
Ideally, somebody would have a ration of like 3.90 to split the difference. I feel like 4.10's might be too much when not towing but 3.73's might have me wishing for more when I am towing. What would you go with? Also, I know with the ecoboost the 4.10's would not be in boost as much as the 3.73's so would it be about equal as far as MPG goes? I currently get 16mpg with 3.31's.
So background- I have a 2018 3.5EB with 3.31's with electronic locker. I added a 2" level and 275/65-20 BFG K02's which are about 34" tall. I enjoyed the acceleration when I first bought the truck, as I think the taller gears allowed me to get into boost sooner. But after adding the tires, the truck has been annoying to drive. It has to downshift way more often, and generally feels sluggish. I find myself driving in tow/haul mode and sport mode more often to keep the RPM higher, and lessen the downshifting.
The truck is mostly driven by my wife, but I drive it on weekends. I would say its a 50/50 mix of highway and city driving. I tow with it occasionally- probably 12-20 times a year, and tow heavy when I do.
So I want to regear the truck, but am a bit torn at what I should do. 3.73's would be a good mix it seems for when I am not towing, but I am sure 4.10's would be appreciated when I am. According to stage3 motorsports Instagram post, the jump from 3.31 to 3.73 would be 270rpm at whatever they figure for highway speed, and the jump from 3.31 to 4.10 would be 520rpm. Does anyone know if this chart is applicable to the new 10speed?
Ideally, somebody would have a ration of like 3.90 to split the difference. I feel like 4.10's might be too much when not towing but 3.73's might have me wishing for more when I am towing. What would you go with? Also, I know with the ecoboost the 4.10's would not be in boost as much as the 3.73's so would it be about equal as far as MPG goes? I currently get 16mpg with 3.31's.
https://www.f150forum.com/f118/re-gearing-433000/
12-26-2018, 10:35 PM
#4
Did you fix your speedometer to account for the tire size change? Going from stock tires to 34" tires changes your effective gear ratio, throws off your speedometer, and affects your shift points and RPM's. Going from a stock 31.5" tire for example to a 34" tire, you've changed your effective gear ratio from 3.31's to 3.06. Calibrating your speedometer will help get you back to proper RPM's.
Also, just FYI, you're getting better MPG's right now than the dashboard would show, if you haven't fixed your speedometer. The MPGs are currently being calculated with the truck thinking you're on smaller tires. But you're actually on larger tires so with each tire revolution you're traveling farther than the truck thinks it's gone. So you're getting more miles per gallon than the dashboard computer would show.
Also, just FYI, you're getting better MPG's right now than the dashboard would show, if you haven't fixed your speedometer. The MPGs are currently being calculated with the truck thinking you're on smaller tires. But you're actually on larger tires so with each tire revolution you're traveling farther than the truck thinks it's gone. So you're getting more miles per gallon than the dashboard computer would show.
Last edited by Florida_F150; 12-26-2018 at 10:48 PM.
12-27-2018, 02:43 AM
#5
Did you fix your speedometer to account for the tire size change? Going from stock tires to 34" tires changes your effective gear ratio, throws off your speedometer, and affects your shift points and RPM's. Going from a stock 31.5" tire for example to a 34" tire, you've changed your effective gear ratio from 3.31's to 3.06. Calibrating your speedometer will help get you back to proper RPM's.
Also, just FYI, you're getting better MPG's right now than the dashboard would show, if you haven't fixed your speedometer. The MPGs are currently being calculated with the truck thinking you're on smaller tires. But you're actually on larger tires so with each tire revolution you're traveling farther than the truck thinks it's gone. So you're getting more miles per gallon than the dashboard computer would show.
Also, just FYI, you're getting better MPG's right now than the dashboard would show, if you haven't fixed your speedometer. The MPGs are currently being calculated with the truck thinking you're on smaller tires. But you're actually on larger tires so with each tire revolution you're traveling farther than the truck thinks it's gone. So you're getting more miles per gallon than the dashboard computer would show.
12-27-2018, 08:10 AM
#6
The easiest way is probably just a handheld programmer / tuner. That's what I did. It looks like a cellphone, you just plug it into the port under the steering wheel and tell it your new tire size, and you're done. You can also get them with built in "tunes" that give you a little extra power or help with fuel economy.
Here's one for just calibrating the speedo for tire size or gear changes (under $200):
https://superchips.com/shop/ford-flashcal-for-truck
I have this one which also includes some canned tunes:
https://superchips.com/shop/f5-ford-flashpaq
Other companies make them too.
The other option is FORScan. You buy a small adapter that plugs into the same port as the programmers above, but instead of using a programmer, you download software to your laptop or smartphone, and you use that to tell the truck what size tires you have. (It also allows you to tweak a lot of other things with your truck, but I have not experimented with it. I wanted the tunes for increased power so I got a programmer).
Here's one for just calibrating the speedo for tire size or gear changes (under $200):
https://superchips.com/shop/ford-flashcal-for-truck
I have this one which also includes some canned tunes:
https://superchips.com/shop/f5-ford-flashpaq
Other companies make them too.
The other option is FORScan. You buy a small adapter that plugs into the same port as the programmers above, but instead of using a programmer, you download software to your laptop or smartphone, and you use that to tell the truck what size tires you have. (It also allows you to tweak a lot of other things with your truck, but I have not experimented with it. I wanted the tunes for increased power so I got a programmer).
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Dredd75 (12-28-2018)
12-27-2018, 09:14 AM
#7
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12-27-2018, 09:20 AM
#8
Did you fix your speedometer to account for the tire size change? Going from stock tires to 34" tires changes your effective gear ratio, throws off your speedometer, and affects your shift points and RPM's. Going from a stock 31.5" tire for example to a 34" tire, you've changed your effective gear ratio from 3.31's to 3.06. Calibrating your speedometer will help get you back to proper RPM's.
Also, just FYI, you're getting better MPG's right now than the dashboard would show, if you haven't fixed your speedometer. The MPGs are currently being calculated with the truck thinking you're on smaller tires. But you're actually on larger tires so with each tire revolution you're traveling farther than the truck thinks it's gone. So you're getting more miles per gallon than the dashboard computer would show.
Also, just FYI, you're getting better MPG's right now than the dashboard would show, if you haven't fixed your speedometer. The MPGs are currently being calculated with the truck thinking you're on smaller tires. But you're actually on larger tires so with each tire revolution you're traveling farther than the truck thinks it's gone. So you're getting more miles per gallon than the dashboard computer would show.
And I may look into the speedo fix, but I don't want to do any tuning to my truck. Too many bad experiences with previous vehicles.
Thanks guys,
12-27-2018, 10:26 AM
#9
I think I may be a little naïve on the subject, but could you explain how the speedo calibration would affect RPM's? I don't see how changing anything but gears would give you more RPM in any given gear. I could see it holding a lower gear for a longer period of time, but I just don't understand how that works.
And I may look into the speedo fix, but I don't want to do any tuning to my truck. Too many bad experiences with previous vehicles.
Thanks guys,
And I may look into the speedo fix, but I don't want to do any tuning to my truck. Too many bad experiences with previous vehicles.
Thanks guys,
https://www.crawlpedia.com/rpm_gear_calculator.htm
When I say calibrate your speedo, I'm referring to telling the on-board computer your new tire size so that everything mentioned above goes back to being accurate.
Right now your speedo is off by some percentage based on the actual difference in tire sizes. You're going faster than the speedo says. It may say you're going 70mph, but you may actually be going closer to 80mph in real life. You can check by using any free GPS speedometer app on a smartphone.
Last edited by Florida_F150; 12-27-2018 at 10:43 AM.
12-27-2018, 01:37 PM
#10
RPM's are a function of four things: Your current speed, axle ratio, transmission ratio for whatever gear you're currently in, and tire size. The truck calculates RPM's based on stock tire size (circumference). If you change the tire size but don't tell the truck's computer, the RPMs, speedometer, and shift points are thrown off. Here's a handy calculator to see it all together:
https://www.crawlpedia.com/rpm_gear_calculator.htm
When I say calibrate your speedo, I'm referring to telling the on-board computer your new tire size so that everything mentioned above goes back to being accurate.
Right now your speedo is off by some percentage based on the actual difference in tire sizes. You're going faster than the speedo says. It may say you're going 70mph, but you may actually be going closer to 80mph in real life. You can check by using any free GPS speedometer app on a smartphone.
https://www.crawlpedia.com/rpm_gear_calculator.htm
When I say calibrate your speedo, I'm referring to telling the on-board computer your new tire size so that everything mentioned above goes back to being accurate.
Right now your speedo is off by some percentage based on the actual difference in tire sizes. You're going faster than the speedo says. It may say you're going 70mph, but you may actually be going closer to 80mph in real life. You can check by using any free GPS speedometer app on a smartphone.