You've got it backwards on calculating gear ratio. You need to count the driveshaft revolutions per 1 tire rotation. A better way is to count driveshaft rotations per ten tire revolutions then divide that by ten. Example: If you rotate the tires 10 times and the driveshaft rotates 41 times then you have a 41:10 ratio which is a 4.10 gear ratio.
When looking at tires it does actually stand for revolutions per mile. These guys do spend more time selling tires and wheels over trying and pinion sets. Might have just been a slip on his part.
The video presentation was referring to engine speed. Tachometers do not measure wheel speed. A tire will revolve the same number of times per mile regardless of speed. The only reason to know revolutions per mile on a tire is for comparison's sake. Therefore, it was a gaffe to refer to engine speed as revolutions per mile. Especially since engine revolutions per mile will change drastically depending on which gear the transmission is in, whether the transfer case is in low range and the dynamic loaded radius of the tire. I'd say static loaded radius, but that doesn't directly matter when moving. We can't readily measure dynamic loaded radius, so we use static loaded radius. Also the explanation of gear ratios was backwards for automobiles. Trucks use gear reduction, more turn in to fewer turns out. Bicycles work on mechanical gain, fewer turns in to more turns out which was the explanation given.
Got it backwards, with a 3.21 gear ratio, your drive shaft will rotate 3.21 times per 1 rotation of the tire. Hence the increase in torque with lower gears (higher numerical number).... more driveshaft rotations per rotation of the tire = more torque transmitted
On my 2Gen Tacoma I have 4.88s with 33s. Still clock 19-20 highway MPG and allows me to go to 35s if I want or tow a trailer and still feel good about the engine not being over stressed. As for daily driving with the 33s on the factory 3.73 ratio, climbing the California/Arizona hills at 70-80 mph it had to downshift into 4th to maintain speed. Now it just trucks up in 5th without issue.
On my 2nd Gen 4dr 2.5l v6 ZR2 Tracker, the stock ratio is 4.875:1 The largest stock tire is 215/70/15. I now run a 5.125:1 ratio with 235/85/16. It puts it back in the zone but just shy of ideal, that being the highest stock ratio available. The v6 power mostly makes up for it but the fuel economy is affected noticeably. My range went from 460-475km per 60l tank down to about 425-435km a tank. It's on a 4+1 lift to clear the rubber and has a custom high articulation suspension un the rear end but still has IFS in the front with a diff drop and overstroked struts that add maybe 1.5" extra flex bit despite thatn the thing is practically unstoppable off road. All the mods I did added a bit over 800lbs to the vehicle, bringing the curb weight up to 3880lbs with me and my gear in it.
The only place a smaller engine saves gas is at idle. Otherwise a larger engine in the same car will add maybe 100 lbs but run at a lower rpm to go the same speed.
Put 285/75/R16 (33") tires on my 2014 2500 Chevy. I've got stock suspension, Ranchhand front bumper, and flatbed installed. Overall vehicle is around 6K lbs. Towing ability after new tires went way down. Upgraded from 4:10 to 4:88 and performance rise to slightly better than stock. The engine is a 6.0 gasser. Don't get stuck in the pasture near as much, and tow hay well enough.
Times are so tough that it's time to simply worry about maintenance and cross our fingers and hope things get better. I've not been off-roading since diesel prices spiked.
Waiting to upgrade my gears, currently. I already have some pricing, just awaiting to fit into my budget. I'm going with 4.88's with front and rear lockers on my 2010 JKU 4-door 3.8L with 35x12.50x18".
Gears are based on tire height, use, and engine power band. If you want to run 35 tires 4.10 to 4.56 is ideal, aggressive off road 4.88 is best. For 37s 4.88 to 5.13 is ideal, 5.36 for aggressive use. Anything over 37 5.13 is the minimum gear. Keep in mind this is based on the v6 engine with no low end torque. The v6 in the Jeep (3.8 and 3.6) makes no low end torque/power thus requires steeper (higher number) gears. With something on the other end, say a 6.7 power stroke) 5.13s would be way overkill based on 37s. You would lose serious gas mpg because your spinning it much higher than needed
I have a JT on 39s. I rolled the stock gears of 3.73s for about 3 months. It seemed fine when I was rolling solo and primarily on flat ground. Offroading on steep inclines I definitely had to step on the gas alot more to get it going. I actually got pretty good mpgs because it took off slow while driving in the city. Regeared to 5.38s because I won't be going any smaller than 39s and I'm going to also be adding alot more weight and possibly towing a lite travel trailer in the future. My JT now feels like a rocket ship in comparison to having the stock gearing. It climbs hills alot better. It doesn't struggle with weight and I'm putting less strain on the engine and drivetrain.
@@kylancook3477 LOL, that was a typo I didn't catch. My mpgs were slightly better while driving in the city because my rig would take off pretty slow from a stop when it wasn't regeared.
2014 Nissan Xterra. Started with 3.13 gears & 265/70/R16. Moved up to 3.73 gears & 315/70/R17. Still working on the regear. Missing a couple tools (46mm socket, setup bearings), should have it rolling soon-ish. I ran the gear ratio/transmission gears through a calculator online and this came up as the most accurate ratio to run to bring it as close to stock as possible.
yep.... believe it or not i get 14mpg city with 30.5 tires with a 2.4 4cyl. does great on the interstate... 20+... but not in the city... im already geared low as crap (20:1 crawl in first in 4 high/2 high) if you cant regear, pedal command or something like thay will probably help because counterintuitively ...sport mode appears to help (shifts a lot later) You cant regear a KL that i know of. i dont even think I can upgrade the torque converter.
This guy has things all messed up. The axle doesn't rotate multiple times per drive shadt revolution. The drive shaft rotates multiple times per tire rotation.
i have a 1997 jeep wrangler with a 2.5 motor and a 5 speed trans with 33x12.50x15 tires what gears should i use for all around performance not really worried to much about gas mileage thanks.
Optimized is the key word. Everyone thinks low rpm = good mpg. these new trucks with 10 gears will mostly stay out of overdrive because the load is too great at speed with stockish gears
You are going to have to drive tens of thousands of miles just to get back to zero with the money spent on gears vs the theoretical tiny improvement in fuel mileage.
Up to $3K to regear a vehicle unless you absolutely need it is a waste of money. You will never recoup that spend in fuel savings. Wear and tear yes, but not fuel economy.
This is false. Power out = power out. It’s the same energy of gas needed. Regearing doesn’t help fuel economy it simply changes your driveline ratios which changes overall crawl ratio and puts your revs in different ranges
@@ImSick0 lol go study it and come back when you understand why you’re wrong. If it saves gas it would only be at a specific speed which nobody drives 1 exact speed. Gas is dependent on resistance on drivetrain not your rpm. Fundamentally you’re converting potential energy (gas) into kinetic energy (motion). You can’t violate physics
@@alexs825 I see you have trouble comprehending. Not only are you saving gas, you're also saving your drivetrain from stress. I've seen plenty of people blow transmissions, clutches etc. after going bigger tires and driving that way for a while and not regearing. Regearing = less stress on drivetrain, and makes the engine work less thus you save gas. Not very hard to comprehend.
@@warkal868 is that mostly city driving? I’m guessing there’s a healthy dose of city driving and that you are pushing down the pedal the same amount before and after regear when accelerating. Well with lower gearing you’re actually not speeding up as quickly which is the equivalent of if you just drove more efficiently without regearing. What do I know I just understand basics of physics. There’s no free lunch you need to burn a specific amount of energy as potential energy to convert to kinetic energy (motion). When you say only regearing saves gas you’re literally claiming the engine is more efficient which is totally a crazy claim. The only way to make an engine more efficient is to speed up slower and use less horsepower per my first point
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You've got it backwards on calculating gear ratio. You need to count the driveshaft revolutions per 1 tire rotation. A better way is to count driveshaft rotations per ten tire revolutions then divide that by ten. Example: If you rotate the tires 10 times and the driveshaft rotates 41 times then you have a 41:10 ratio which is a 4.10 gear ratio.
Interesting. Thank you for this
RPMs stand for Revolutions Per Minute. Not Revolutions Per Mile as stated in the video.
When looking at tires it does actually stand for revolutions per mile. These guys do spend more time selling tires and wheels over trying and pinion sets. Might have just been a slip on his part.
When it comes to tires, there is a revs per mile spec...
The video presentation was referring to engine speed. Tachometers do not measure wheel speed. A tire will revolve the same number of times per mile regardless of speed. The only reason to know revolutions per mile on a tire is for comparison's sake. Therefore, it was a gaffe to refer to engine speed as revolutions per mile. Especially since engine revolutions per mile will change drastically depending on which gear the transmission is in, whether the transfer case is in low range and the dynamic loaded radius of the tire. I'd say static loaded radius, but that doesn't directly matter when moving. We can't readily measure dynamic loaded radius, so we use static loaded radius. Also the explanation of gear ratios was backwards for automobiles. Trucks use gear reduction, more turn in to fewer turns out. Bicycles work on mechanical gain, fewer turns in to more turns out which was the explanation given.
I concur
Add lockers at the same time. It’ll save from having to pay for installation in the future.
$$$$
Got it backwards, with a 3.21 gear ratio, your drive shaft will rotate 3.21 times per 1 rotation of the tire. Hence the increase in torque with lower gears (higher numerical number).... more driveshaft rotations per rotation of the tire = more torque transmitted
On my 2Gen Tacoma I have 4.88s with 33s. Still clock 19-20 highway MPG and allows me to go to 35s if I want or tow a trailer and still feel good about the engine not being over stressed. As for daily driving with the 33s on the factory 3.73 ratio, climbing the California/Arizona hills at 70-80 mph it had to downshift into 4th to maintain speed. Now it just trucks up in 5th without issue.
On my 2nd Gen 4dr 2.5l v6 ZR2 Tracker, the stock ratio is 4.875:1 The largest stock tire is 215/70/15. I now run a 5.125:1 ratio with 235/85/16. It puts it back in the zone but just shy of ideal, that being the highest stock ratio available. The v6 power mostly makes up for it but the fuel economy is affected noticeably. My range went from 460-475km per 60l tank down to about 425-435km a tank. It's on a 4+1 lift to clear the rubber and has a custom high articulation suspension un the rear end but still has IFS in the front with a diff drop and overstroked struts that add maybe 1.5" extra flex bit despite thatn the thing is practically unstoppable off road. All the mods I did added a bit over 800lbs to the vehicle, bringing the curb weight up to 3880lbs with me and my gear in it.
I just bought a set of 4.56 gears for a 2001 XJ. I plan on only 33” tires but I’ll be able to lug more stuff comfortably with low a ratio.
The only place a smaller engine saves gas is at idle. Otherwise a larger engine in the same car will add maybe 100 lbs but run at a lower rpm to go the same speed.
Put 285/75/R16 (33") tires on my 2014 2500 Chevy. I've got stock suspension, Ranchhand front bumper, and flatbed installed. Overall vehicle is around 6K lbs. Towing ability after new tires went way down. Upgraded from 4:10 to 4:88 and performance rise to slightly better than stock. The engine is a 6.0 gasser. Don't get stuck in the pasture near as much, and tow hay well enough.
Times are so tough that it's time to simply worry about maintenance and cross our fingers and hope things get better. I've not been off-roading since diesel prices spiked.
Waiting to upgrade my gears, currently. I already have some pricing, just awaiting to fit into my budget. I'm going with 4.88's with front and rear lockers on my 2010 JKU 4-door 3.8L with 35x12.50x18".
Gears are based on tire height, use, and engine power band. If you want to run 35 tires 4.10 to 4.56 is ideal, aggressive off road 4.88 is best. For 37s 4.88 to 5.13 is ideal, 5.36 for aggressive use. Anything over 37 5.13 is the minimum gear.
Keep in mind this is based on the v6 engine with no low end torque. The v6 in the Jeep (3.8 and 3.6) makes no low end torque/power thus requires steeper (higher number) gears. With something on the other end, say a 6.7 power stroke) 5.13s would be way overkill based on 37s. You would lose serious gas mpg because your spinning it much higher than needed
New gear ratio = new tire size × old gear ratio ÷ old tire size
I have a JT on 39s. I rolled the stock gears of 3.73s for about 3 months. It seemed fine when I was rolling solo and primarily on flat ground. Offroading on steep inclines I definitely had to step on the gas alot more to get it going. I actually got pretty good mpgs because it took off slow while driving in the city.
Regeared to 5.38s because I won't be going any smaller than 39s and I'm going to also be adding alot more weight and possibly towing a lite travel trailer in the future. My JT now feels like a rocket ship in comparison to having the stock gearing. It climbs hills alot better. It doesn't struggle with weight and I'm putting less strain on the engine and drivetrain.
Took off drive train?
@@sam_s_ ?
@@TheHitSquadOffroad pretty good mpg because it took off drivetrain?
@@kylancook3477 LOL, that was a typo I didn't catch. My mpgs were slightly better while driving in the city because my rig would take off pretty slow from a stop when it wasn't regeared.
@@TheHitSquadOffroad np👍
2014 Nissan Xterra.
Started with 3.13 gears & 265/70/R16.
Moved up to 3.73 gears & 315/70/R17. Still working on the regear. Missing a couple tools (46mm socket, setup bearings), should have it rolling soon-ish.
I ran the gear ratio/transmission gears through a calculator online and this came up as the most accurate ratio to run to bring it as close to stock as possible.
yep.... believe it or not i get 14mpg city with 30.5 tires with a 2.4 4cyl.
does great on the interstate... 20+... but not in the city...
im already geared low as crap (20:1 crawl in first in 4 high/2 high)
if you cant regear, pedal command or something like thay will probably help because counterintuitively ...sport mode appears to help (shifts a lot later)
You cant regear a KL that i know of. i dont even think I can upgrade the torque converter.
This guy has things all messed up. The axle doesn't rotate multiple times per drive shadt revolution. The drive shaft rotates multiple times per tire rotation.
I run 488s in my '06 TJ.
I have a 2014 JK I am re-gearing from 321s to 4/88 it’s been really sucking the gas with 321s
i have a 1997 jeep wrangler with a 2.5 motor and a 5 speed trans with 33x12.50x15 tires what gears should i use for all around performance not really worried to much about gas mileage thanks.
You got the gear ratio backwards on the explanation. It's how many time the DS /trans rotates for 1 full revolution of the tire.
I'm not doing anymore upgrades till economy gets better, use what I have and no unnecessary buying
I keep telling myself the same thing, but my wallet will tell you a different story!
I switch tires from 35s to 37
Optimized is the key word. Everyone thinks low rpm = good mpg. these new trucks with 10 gears will mostly stay out of overdrive because the load is too great at speed with stockish gears
Should I regear with 33s in a Toyota Tacoma Trd off road 2021? And if I need to which one 4.88 or 5.29
Just trade the truck. It’s trash 🤣
@@ShaunsJeep hahaha
Yes. Everyone uses 5.29 on 3rd gen Tacoma's.
On a 2021 Tacoma on 33's automatic transmission 5.29 / manual 4.88.
Um... you got it backwards.
You are going to have to drive tens of thousands of miles just to get back to zero with the money spent on gears vs the theoretical tiny improvement in fuel mileage.
Up to $3K to regear a vehicle unless you absolutely need it is a waste of money. You will never recoup that spend in fuel savings. Wear and tear yes, but not fuel economy.
Where do you pay $3000? I paid $1850 on my 4wd with parts included.
@@ImSick0 where did you get it all so cheap
@@ImSick0 I guess you missed the part where I said up to as smany have paid up to that amount or more.
@@jamesmcgarry8660 So many? This is literally the first time I hear about that price.
@@ImSick0 I got quoted 1399
Did you really just say RPM stands for revolutions per mile😂😂😂 I know we all make mistakes and it did make me laugh
Hahaha!! Nice catch!! Lol didn’t even realize I said that! 😂
Don't mod it and you will get the best mpg...
Dude you need to get your info right. Your all backwards.
81,000,000 votes....
You have absolutely no idea what you’re talking about.
This is false. Power out = power out. It’s the same energy of gas needed. Regearing doesn’t help fuel economy it simply changes your driveline ratios which changes overall crawl ratio and puts your revs in different ranges
The vehicle works less harder when geared so it burns less gas.
@@ImSick0 lol go study it and come back when you understand why you’re wrong. If it saves gas it would only be at a specific speed which nobody drives 1 exact speed. Gas is dependent on resistance on drivetrain not your rpm. Fundamentally you’re converting potential energy (gas) into kinetic energy (motion). You can’t violate physics
@@alexs825 I see you have trouble comprehending. Not only are you saving gas, you're also saving your drivetrain from stress. I've seen plenty of people blow transmissions, clutches etc. after going bigger tires and driving that way for a while and not regearing. Regearing = less stress on drivetrain, and makes the engine work less thus you save gas. Not very hard to comprehend.
If it false, why am I getting better fuel economy after just regearing?
@@warkal868 is that mostly city driving? I’m guessing there’s a healthy dose of city driving and that you are pushing down the pedal the same amount before and after regear when accelerating. Well with lower gearing you’re actually not speeding up as quickly which is the equivalent of if you just drove more efficiently without regearing. What do I know I just understand basics of physics. There’s no free lunch you need to burn a specific amount of energy as potential energy to convert to kinetic energy (motion). When you say only regearing saves gas you’re literally claiming the engine is more efficient which is totally a crazy claim. The only way to make an engine more efficient is to speed up slower and use less horsepower per my first point