Having a hard time deciding whether to switch.

I'm looking at either a LT275/65R20 Nitto Terra Grappler or going to a LT285/75R17.

If I go to 17", I need to find some decent wheels, but I'm on a budget under $200 for the wheel only, and the tires are only $50 cheaper.

However, I don't want to hurt my performance any by going to the heavy 20" tire size but I'd like a touch taller tire on the 20" or about the same size with a 17" wheel.

Does the wheel or tire weigh more normally?

I'm looking at either the Centerlines or an American Racing Teflon coated wheel.

Which would work better for performance and lifespan of parts on the truck? About the same?

Trying to avoid a re-gear, and not go much different in size of tires either direction.

Thanks!

I'AM GETTING READY TO GO TO 22" WHEELS AND TIRES FOR SHOW. DON'T KNOWN HOW TO ANSWER YOUR QUESTION.

I can't absolutely swear to this but as I recall the factory 20's are 33 inches tall and as long as you stay near to that same height you shouldn't have to regear.
You could look at either Desert Rat or the Tire Rack, both on line and maybe find something that fits your needs.

Stick with the 20"s. You already have them. Spend the extra getting better tires.

quote:

Originally posted by Bamataco:
I can't absolutely swear to this but as I recall the factory 20's are 33 inches tall and as long as you stay near to that same height you shouldn't have to regear.
You could look at either Desert Rat or the Tire Rack, both on line and maybe find something that fits your needs.

the factory 20 inch rims and tires that come on the ram that are a 32.5 over all. i am going to down grade from the factory inch 20 to a 17x9 or a 17x10 rim so i can run the 305/70/17 all around. if you have any questions let me know.

Personally, I prefer 17" rims... I've had the stock 17" chrome rims, the stock 20" flower pots, 20" steelies, and now 17"x9" MB Motoring rims.

The truck just seems to have more power w/o all that rim weight and it's awesome!

quote:

Originally posted by Lucky Devil:
Personally, I prefer 17" rims... I've had the stock 17" chrome rims, the stock 20" flower pots, 20" steelies, and now 17"x9" MB Motoring rims.

The truck just seems to have more power w/o all that rim weight and it's awesome!

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And besides that there is greater tire selection at better prices for 17's.

This is the very thing I was trying to decide aswell I like my 20's but it's about time for tires but if I chage the wheels and tire size can I not lower the gearing? I have 3.92 now but would like to be closer to 4.10 Not sure how all this tire stuff works

You can still change the gearing. I have 17's and I'm going with 4.56 gears. You don't need big tires for big gears...

quote:

And besides that there is greater tire selection at better prices for 17's.

I had a chance to trade my 17s for 20s once,that's the main reason I didn't do it,and also the main reason the other guy wanted to trade. And I just like the looks of the 17s better,never was a big fan of the big rims.

quote:

Originally posted by hemi06ram:
This is the very thing I was trying to decide aswell I like my 20's but it's about time for tires but if I chage the wheels and tire size can I not lower the gearing? I have 3.92 now but would like to be closer to 4.10 Not sure how all this tire stuff works

I don't know how to figure it out but if you go to shorter tires you will effectively change your gear ratio closer to the 4:10's you want.
I'm sure if you ask around enough you can find some one that can figure this out for you.

quote:

Originally posted by hemi06ram:
This is the very thing I was trying to decide aswell I like my 20's but it's about time for tires but if I chage the wheels and tire size can I not lower the gearing? I have 3.92 now but would like to be closer to 4.10 Not sure how all this tire stuff works

http://www.ramblerman.com/blazer/gearcalc.htm

I was playing around with this. I have roughly a 33" tire with the 275/60/20s and a 3.92 gear and figured out that a 31" tire would give me a 4.17 rear gear ratio.

I would like to drop to 17's from these 20's too. I never wanted the 20's to start with but the deal on the truck could not be passed up. Besides, all the other trucks around here had the 20's as well. I couldn't find an 08 with 17's.

Not so much due to the replacement cost of the tires, as it all depends on what you buy( I can get excellent 20" AS tires for less, a LOT less actually, than most 17" AT's ), but more so because I just don't like the huge tires and rims. I like the look of the 17's better. Just not a fan of those huge 20" rims.

My biggest concern if I do swap to the 17's is what effect will it have on fuel economy when paired with the 3.92 gears? That will raise RPM's. Even a small rise in RPM's will hurt MPG some and let's be honest the fuel economy in these trucks is awful to begin with so anything that makes it worse IMO is something to seriously consider. Gas prices ARE going back up into the $4+ range at some point. The less RPM's rise the better for fuel economy so I certainly will try and keep them as low as I can if I do swap to 17's.

You also have to take into account the weight difference. Will dropping down in tire size actually lower the final rim and tire combo weight? While the 20's are a bigger tire there is a lot less sidewall to them. The rim makes up more of the overall size than the tires do. The 17's, especially if you went with 285's to try and keep the same approx diameter are some BIG tires. I did a little checking on tire weights and you might be surprised at the results I will post below.

Starting OE tire & weight = Goodyear Wrangler HP AS 275/60-20 @ 43 lbs each. So, if you drop to a 17 will it actually weigh less? All depends on the kind of tire you choose. Here are a few examples and I will use some popular AS and AT tires in each size( if available )as examples. Keep in mind as well that tire weight varies from mfg to mfg and model to model.

NOTE - unless noted all tires are standard P-Metric series. LT's will almost always weigh significantly more( as would MT's if you went that route ). All weights and available tires in the sizes listed were obtained through Tirerack to make it easier for me...

265/70-17:
Firestone Destination LE AS = 41 lbs
Michelin LTX M/S AS = 40 lbs
BF Goodrich TA KO AT( LT series )= 47 lbs Load C / 55 lbs Load E
Bridgestone Dueler AT Revo = 43 lbs P Series / 49 lbs LT Series Load E

275/70-17:
Firestone Destination AT = 47 lbs Load C LT Series
Goodyear Wrangler AT Extreme = 51 lbs Load C LT Series
Goodyear Wrangler AT/S = 40 lbs Load C LT Series
Goodyear Wrangler Silent Armor = 53 lbs Load C LT Series

285/70-17:
BF Goodrich TA KO AT = 58 lbs Load D LT Series
Bridgestone Dueler AT Revo = 54 lbs Load D LT Series
Firestone Destination AT = 44 lbs P Series / 52 lbs Load D LT Series
Michelin LTX A/T 2 = 57 lbs Load D LT Series

I have no idea what the stock 20's weigh nor what the aftermarket/OEM 17's weigh either so I can't factor that in. One thing is for sure though the 17" rims need to weigh less than the 20" rims to really ensure you actually reduce the overall weight if you go with the larger diamteter 17" tires. From what I have come up with most times the 17" tires weigh as much as, or even significantly more than, the stock 20" tires. That means dropping to 17's is not a guarantee of weight savings as you would initially think unless the rims weighed a LOT less.

A tire size swap will also throw the speedo off which will have to be fixed. Not a huge change but enough that if you aren't careful it could push you into the cop's ticket range if you exceed the speed limit by a lot to start with. Not sure on these trucks but on some it also effects your odometer. If I do change tire sizes I will be sure and have the computer flashed to the correct size.

I would need to go to something like a 285/70-17 to keep the same approx tire size but in that size the tires weigh a LOT more. MY tire options are more limited as well and I would end up having to go with a more aggressive AT tread which doesn't help MPG either. What I really want is to go to some 265/70-17's. That is a very popular size with tons of affordable tire options to choose from and the ones I would buy do weigh a little less than the stock 20's( about 10lbs total weight savings vs the stock 20" Wrangler HP's ). I would really save some weight only if the rims I got weighed a lot less than my aluminum OE 20's. I could actually end up adding weight if I am not careful.

Decisions deciscions...

I am bored right now so I also looked up some rough RPM & Speedo differences with the various tire sizes as well.

275/60-20 = 32.99" approx 1677 RPM's @ 60 MPH
265/70-17 = 31.60" approx 2.6 MPH too fast & + 75 RPM's @ 60MPH
275/70-17 = 32.15" approx 1.5 MPH too fast & + 45 RPM's @ 60MPH
285/70-17 = 32.70" approx 0.5 MPH too fast & + 15 RPM's @ 60MPH

Lots of stuff involved in the decision to drop down to 17's from 20's. Not as clear cut and dried as you would think.

This message has been edited. Last edited by: NHHEMI,

For the Info. I think I'm gonna get some 17's maybe I'll find someone to trade with.

quote:

Originally posted by hemi06ram:
For the Info. I think I'm gonna get some 17's maybe I'll find someone to trade with.

I'm sure it won't be too hard to find somebody wanting to trade