jQuery not supported.



How to determine proper gear ratios

How to determine proper gear ratios

Postby nateowens16 [OP] » Oct 09 2019, 7:51pm

I've tried searching around the forum and cant find a exact answer to my question, so ill ask since it has to do with gear ratios. I have a 2016 1500 with the 6.2 and 3.23 gears in it with the 8 speed trans. I bought the truck with 325/50r22 on it which is basically a 35 inch tire and 13 wide. I want to move up to a 37 inch tire and i tow a 14ft trailer with a rzr on it so nothing super heavy. My main question is that would it be worth it to swap the gears out to something like 3.73 and have Lew right me a custom tune. I know if i go anymore than 3.73 with my gears i will be into a lot more money and not looking to do that.
Original Poster
nateowens16
Newbie
Newbie
Posts: 1
Joined: Oct 09 2019, 7:38pm
Location: NC
Year: 2016
Make/Model: Chevrolet Silverado
Extra Info: LTZ 6.2 4x4
Group Membership:
Registered users

Re: How to determine proper gear ratios

Postby hunt4steve » Oct 09 2019, 9:11pm

Did you plug your numbers into the gear calculator?

BTW, I'd move to 4.10 gears, and make it easier on your transmission over the daily driving.

https://docs.google.com/spreadsheets/d/ ... 1905211263


edit, I see that you did. The Ring and Pinion size is the not the Ring gear size, but the ratio. I'll fix that.
And, your transmission gear is the gear that you would be driving in, such as 6th gear, on an 8L90 is 1.00.


Running your numbers; installing 37" tires and 3.73 gears, will effectively net you 3.51 gears, which is better than the stock 3.23 gears, and put your RPMs around 2034 at 60 mph.

With 37" tires and 3.73 gears, in 8th gear at 75mph, your RPMs would be around 1652, pretty nice.

If you did NOT change your gears, and installed 37" tires, in 8th gear at 75MPH, your RPMs would be around 1431.

Seems like this would be a question about power. The 6.2 is a big engine, and may have the grunt to power through this small percentage of change.

Are those 34.5 tires stock tires for that truck?
User avatar
hunt4steve
Armed Forces
Armed Forces
Combustion on 4 pistons [L2]
Combustion on 4 pistons [L2]
Posts: 432
Topics: 11
Images: 3
Joined: Dec 01 2015, 4:29am
Years of membership: 3 years of membership3 years of membership3 years of membership
Location: NM
Year: 2017
Make/Model: Chevrolet Silverado
Extra Info: 4x4 CC LTZ Midnight
Group Membership:
Registered users
Servicemen

Re: How to determine proper gear ratios

Postby Bradley21sanders » Oct 09 2019, 10:10pm

Id like to know what lift wheels and tires you are planning to run with pictures when you do it! ha start a build thread

I originally had 3.42s in my 5.3 1500 with 33x11 (6 speed trans .6x in 6th gear)

Went to 4.11s with same tire

just redid it again, since I was replacing the carrier and the pinion sheared a tooth, 4.56s with a eaton truetrac


All of that said I would suggest 4.10s at minimum with 37s don't fear the gear.

You do have the 6.2 and the 8 speed (.6x in 8th gear) so more power than me.. meaning yeah 3.73s would probably be good but why the price difference between 3.73s and 4.10s is negligible.
Bradley21sanders
Auto 4WD Mode [L3]
Auto 4WD Mode [L3]
Posts: 1691
Topics: 47
Images: 53
Joined: Dec 10 2012, 10:15pm
Years of membership: 6 years of membership6 years of membership6 years of membership6 years of membership6 years of membership6 years of membership
Location: Monette, AR
Year: 2009
Make/Model: Chevrolet Silverado
Extra Info: 1500 5.3l 2WD
Group Membership:
Registered users

Re: How to determine proper gear ratios

Postby 19trax9519trax95 is online! » Oct 09 2019, 10:50pm

With 37s and towing (and even not towing) I'd want at least a 4.30 or so. But even that is pretty tall imo for 37s.

I'd be looking more at the 4.56- 4.88 range.

37s are really getting up there in size and will be really heavy. Save the 4.10 for stock tires to a 33" tire.

Above a 33 you really need all the help you can get Haha.
Image
User avatar
19trax9519trax95 is online!
Staff Member
Staff Member
Shifting into Sixth Gear! [L3]
Shifting into Sixth Gear! [L3]
Posts: 13422
Topics: 113
Images: 3
Joined: Apr 17 2012, 1:42am
Years of membership: 7 years of membership7 years of membership7 years of membership7 years of membership7 years of membership7 years of membership7 years of membership
Location: Eastern PA
Year: 2017
Make/Model: Chevrolet Silverado
Variant: All Star Edition
Extra Info: 1500 5.3L Z71
Group Membership:
Automotive Technicians
How-to Authors
TOTM Winner
Member Extraordinaire
Global moderators
Registered users

Re: How to determine proper gear ratios

Postby Bradley21sanders » Oct 10 2019, 1:56am

Good to know, didn’t know how much the 6.2 and 8sp (even though the final is roughly the same) played into it
Bradley21sanders
Auto 4WD Mode [L3]
Auto 4WD Mode [L3]
Posts: 1691
Topics: 47
Images: 53
Joined: Dec 10 2012, 10:15pm
Years of membership: 6 years of membership6 years of membership6 years of membership6 years of membership6 years of membership6 years of membership
Location: Monette, AR
Year: 2009
Make/Model: Chevrolet Silverado
Extra Info: 1500 5.3l 2WD
Group Membership:
Registered users

Re: How to determine proper gear ratios

Postby 19trax9519trax95 is online! » Oct 10 2019, 2:11am

The 8 speed definitely helps.

But not nearly enough to offset the tall and heavy tires. Definitely needs to be at least 4.56 imo. Maybe even 4.88

I for sure wouldn't bother with 4.10 though. That's a good ratio for stock to maybe 33s.
Image
User avatar
19trax9519trax95 is online!
Staff Member
Staff Member
Shifting into Sixth Gear! [L3]
Shifting into Sixth Gear! [L3]
Posts: 13422
Topics: 113
Images: 3
Joined: Apr 17 2012, 1:42am
Years of membership: 7 years of membership7 years of membership7 years of membership7 years of membership7 years of membership7 years of membership7 years of membership
Location: Eastern PA
Year: 2017
Make/Model: Chevrolet Silverado
Variant: All Star Edition
Extra Info: 1500 5.3L Z71
Group Membership:
Automotive Technicians
How-to Authors
TOTM Winner
Member Extraordinaire
Global moderators
Registered users

Return to Transmission/Drivetrain

 

  • Similar topics
    Replies
    Views
    Last post

Common search terms

tires stock same truck since determine gear proper ratios nice getting wheels installed power lift help make right engine

It is currently Oct 21 2019, 11:56pm

  • Sponsor
Login  •  Register
Transmission/Drivetrain Forum
Transmission/DrivetrainTransmission and drivetrain related components. Discuss automatic and manual trans repairs and performance or talk about driveshafts or rear-ends and differentials. Diagnostics of 4-speed, 5-speed, or even 6-speed transmissions.
To create a new topic in Transmission/Drivetrain, click this button:
Previous topic Next topic
Sitewide News Sitemaps & Feeds

Who is online

Users browsing this forum: No registered users and 42 guests