Change Tires From 285/60 R18 To 35"s

[mn338]

Hi,

I will change my tires up to 35"s.

What will my driving conditions be when I use my stock gears?

And what gear seize is the best if I drive 70% Highway (Autobahn - most time I drivde 70mph - sometimes 75-80mph not faster) and 30% city traffic.

I do not drive offroad, btw my gmc is a 2wd.

 

what are the perfect gears for my truck?

and what other parts do i need for it?

 

thanx

 

malte

[05silvycrew]

I'll take a stab at this. you've got a couple options.

 

1) re-gear your truck with a different ring and pinion and get a handheld tuner to adjust your computer for tire size and axle ratio. as to what ratio...I would recommend at least a 4.10 set, all the way up to a 4.56 ratio. re-gearing has to be done precisely, so maybe let a certified shop handle that. Not sure if you've got a locker in the rear, sounds like you don't do much off-roading so that might not be a big issue.

 

2) find a stock rearend out of a junkyard with 4.10 gears. if you want a locker, make sure the axle has the G80 option. work with them and see if they'll take cash and your axle as a trade in. that should bolt right up in place of yours. again, you'll need a handheld tuner to adjust your computer for tire size and the new axle ratio.

 

option 2 might be cheaper if you can find a good deal and a good junkyard to work with.

 

4.10's will put you right around 2000 RPMs at 72 MPH

4.56's will put you right around 2200 RPMs at 72 MPH

 

hope that helps some