Biggest Tires for 3.21 gearing

ExcuseTheN00b

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I just purchased my 2019 Bighorn 4x4 and I am looking to install bigger tires. I really want 35s but have seen some people mention that with the 3.21 gearing that it would not be a good idea for the longevity of the truck. I was wondering what would be the best/safest biggest tire to install without putting a ton of stress on the motor. I know installing anything bigger than stock will add some stress and decrease mpg. I also want to change the stock 20s to the Fuel Assault 20 x 10 with -18 offset and go with Nittos regardless of size tire. Also will level the front end to clear the tires. Any help would be greatly appreciated since this is my first brand new truck and don't want to ruin it within a few years of having it. I don't do much or any offroad driving.
 

DonsRam19

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I just purchased my 2019 Bighorn 4x4 and I am looking to install bigger tires. I really want 35s but have seen some people mention that with the 3.21 gearing that it would not be a good idea for the longevity of the truck. I was wondering what would be the best/safest biggest tire to install without putting a ton of stress on the motor. I know installing anything bigger than stock will add some stress and decrease mpg. I also want to change the stock 20s to the Fuel Assault 20 x 10 with -18 offset and go with Nittos regardless of size tire. Also will level the front end to clear the tires. Any help would be greatly appreciated since this is my first brand new truck and don't want to ruin it within a few years of having it. I don't do much or any offroad driving.
To play it safe I'd go 33's. They'll look good and there not much bigger then stock so you shouldn't have a problem.
 

ksn240

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33s will fit with just a level. I'm running 305/55r20s, basically a 33x12.50, on a 20x10 -25 offset and have no rubbing. I did take my mudflaps off prior to this because I installed Bushwacker fender flares, so that may change it for you. I have about a half inch of clearance and haven't felt a rub even in reverse and full lock.
 

SColang22

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I just purchased my 2019 Bighorn 4x4 and I am looking to install bigger tires. I really want 35s but have seen some people mention that with the 3.21 gearing that it would not be a good idea for the longevity of the truck. I was wondering what would be the best/safest biggest tire to install without putting a ton of stress on the motor. I know installing anything bigger than stock will add some stress and decrease mpg. I also want to change the stock 20s to the Fuel Assault 20 x 10 with -18 offset and go with Nittos regardless of size tire. Also will level the front end to clear the tires. Any help would be greatly appreciated since this is my first brand new truck and don't want to ruin it within a few years of having it. I don't do much or any offroad driving.
I have 35’s and had them on my other ram with 3.21s. Never had an issue. Take it off-roading a lot
 

ExcuseTheN00b

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How would 22s compare to 20s?
I have 35’s and had them on my other ram with 3.21s. Never had an issue. Take it off-roading a lot
I would love to get a 3.5 inch lift, 35s and Fuel Assaults 22s but I just want to be cautious. I have read people have no problems and others having problems after a few years with the 3.21.
 

SColang22

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How would 22s compare to 20s?

I would love to get a 3.5 inch lift, 35s and Fuel Assaults 22s but I just want to be cautious. I have read people have no problems and others having problems after a few years with the 3.21.
I had and 3.5” lift with 35s and ran them for 80k miles. Never had an issue and I took them off road a lot. I can see the 6 speed having an issue but these 8 speeds have no problem. Ideally you would want at least a 4.10 ratio but it you are highway driving and not towing you should have no issues
 
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SColang22

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How would 22s compare to 20s?

I would love to get a 3.5 inch lift, 35s and Fuel Assaults 22s but I just want to be cautious. I have read people have no problems and others having problems after a few years with the 3.21.
20 vs 22 wouldn’t really matter. You tire would still be 35”
 

ExcuseTheN00b

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20 vs 22 wouldn’t really matter. You tire would still be 35”
I know it would still be either a 33 or 35 depending on what I pick but didn’t know if there would be a lot more stress on the motor or transmission with 22s. Last time I ever did any tires/rim upgrades was to a 2003 Chevy Monte Carlo over 10 years ago with 22s and super slim tires. I was a teen then and didn’t care about causing problems to the car.
 

SColang22

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I know it would still be either a 33 or 35 depending on what I pick but didn’t know if there would be a lot more stress on the motor or transmission with 22s. Last time I ever did any tires/rim upgrades was to a 2003 Chevy Monte Carlo over 10 years ago with 22s and super slim tires. I was a teen then and didn’t care about causing problems to the car.
Yea that’s what I mean. The diameter of the tire is what causes the problem not the wheels. Getting a tuner to change your tire size in the computer will help as well. Also I would be careful with a -18 offset. I think that close to what stock is. I’m running 35/12.5 with stock wheels and I rubbed on the upper control arms. 1/4 spacer fixed it but I read +1 offset brings it far enough off with no UCA rub and no trimming
 

ExcuseTheN00b

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Yea that’s what I mean. The diameter of the tire is what causes the problem not the wheels. Getting a tuner to change your tire size in the computer will help as well. Also I would be careful with a -18 offset. I think that close to what stock is. I’m running 35/12.5 with stock wheels and I rubbed on the upper control arms. 1/4 spacer fixed it but I read +1 offset brings it far enough off with no UCA rub and no trimming
I thought stock wheels were +18 or +19. Once again I honestly have very little knowledge in this and probably am wrong. I have seen some with 33s and 20s -18 offset with no trimming or rubbing with a level. Never saw them mention any spacers tho.
 

ksn240

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Yea that’s what I mean. The diameter of the tire is what causes the problem not the wheels. Getting a tuner to change your tire size in the computer will help as well. Also I would be careful with a -18 offset. I think that close to what stock is. I’m running 35/12.5 with stock wheels and I rubbed on the upper control arms. 1/4 spacer fixed it but I read +1 offset brings it far enough off with no UCA rub and no trimming
Stock wheels are +19. He is looking at -18 so he will be far away from the control arm. His issue will be rubbing the inside of the fenders but with a 33 and a level it will be fine.
 

SColang22

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I thought stock wheels were +18 or +19. Once again I honestly have very little knowledge in this and probably am wrong. I have seen some with 33s and 20s -18 offset with no trimming or rubbing with a level. Never saw them mention any spacers tho.
Yes you are right! Sorry I miss read it. -18 on 33’s should be good. 35s will rub with that offset though. I needed spacers because with the stock wheels my tire hit the UCA. If I went after market with the +1 offset it would do the same as my spacers
 

ExcuseTheN00b

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I really appreciate all the help. I think I am going to go with 33 tires and 20 wheels. I will update whenever I get everything done with pictures within a month.
 

Joeyp

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Yea that’s what I mean. The diameter of the tire is what causes the problem not the wheels. Getting a tuner to change your tire size in the computer will help as well. Also I would be careful with a -18 offset. I think that close to what stock is. I’m running 35/12.5 with stock wheels and I rubbed on the upper control arms. 1/4 spacer fixed it but I read +1 offset brings it far enough off with no UCA rub and no trimming
Our stock offset is positive 19....stock offsets are usually positive not negative
 
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