I am going to go from the stock 265/70/17 to the significantly taller 285/75/17 on my '04.5 2wd SRW 3500. I have the original new "never hit the ground" Michelin 265/70/17 spare. I'm not looking to spend an extra $225 or so if I don't have to, but if I buy only 4 new tires and keep my current spare, should I have a flat on the rear I would have to remove a front 285/75/17 and place it on the rear while putting the spare up front. I had to do that once in Oklahoma during a sleet storm - not good, not good at all!!

What do most of you do about a spare when going to a larger tire size? I would be happy to buy a used 285/75/17, but they haven't been around long enough to be a common used size at the local tire shops.

 

That's not that big a change in tire size, 31.6 inches tall vs. 33.8. The stock spare should work fine for a spare, with the diff taking up the slack. I've done it a little differently on vehicles in the past, getting a matching rim, and rotating the spare through the loop. It costs 20% more, but you get 20% more tire life.

 

WELL first they are 285 70 17. not 285 75 17's LOL. but i would see if you could buy a GOOD used one for the spare. might even be able to trade your stock spare for it? We do that sort of thing all the time at work. If you were closer i would give you a good one for a spare i have several i have saved from work.

 

Sorry Johnny, but you are incorrect. Toyo and Nitto make a 285/75/17 tire- Nitto makes the Dura Grappler, Terra Grappler and a extreeme offroad tire in that size that I know of. The Toyo Open Country AT comes in a 285/75/17 as well.

Normally I cycle the spare into the rotation mix, this time I did not for no good reason - I just didn't.

A nearly 2.25" diameter difference is significant when running a limited slip diff. Whether it is enough to cause damage or not, I'm not sure, but I don't want to find out.

I think I'll buy the 5th 285/75/17 and sell the 265/70/17 Michelin to someone wishing to upgrade their stock size spare.

 

I am also going to be going to the Nitto Duras in a 285/75/17 from a 265. I plan on getting a used 285 from my buddy at Discount when he gets one in. Until then I will keep the stock 265 as a spare and in the off chance I need to change it I will put it on the front like you explained.

 

I too am looking at the 285/75/17 tires, if the original's will ever wear out. (60,000 miles so far.) Will this size tire fit as a spare in the original location? 2006, quad cab, short bed.

 

Buy 4 tires when you need a rotation buy another and throw it in the rotation. Put the used tire under the truck.

 

I have a used 285/70-17 BFG AT if any of you want one just for a spare. PM me if interested and we can discuss.....

 

I went to 285/70 from 265s. I only bought 4 and I'm looking to pick up a single for the spare. Even if it would be used or mostly worn down, it would be closer in size than the 265 spare. Especially if it was needed on the rear.

 

Try to make a trade and pay some cash for a new one or tell the tire shop to call you next time he gets a used one off someone elses truck and work out a deal on that one.

 

You didn't mention an LS diff, so I hadn't thought of that. Still only a difference of 43 revolutions/mile, so shouldn't be to bad. Not my truck, so I can offer all kinds of opinions

 

Get the spare if you are going to run different size tires than stock. Then sell the spare on ebay or the classifieds to off set the cost of the new spare. This way you do not have to worry about it when you do need it. Just rotate it into your rotatation and be done with it.

Shawn.

 

Aside from accelerated tread wear, the AAM axle's TracRite Torsen gear differential under the OP's 3rd Gen won't have an issue with assymetric tire sizes - so emergency use if fine.

The cltuch packs used in the 2nd Gen Rams' Dana limited-slip rear axles are also subject to increased wear, although the tires usually still lose to either the TracLok or PowerLok.

 

Thanks for the feedback everyone!!

This morning I checked with a shop in town I have done business with before. They can get the Nitto LT285/75/17E. 5 of them mounted, balanced, incl. taxes (OTD) for $1150 and they get my 5 tires. That's good enough, so I ordered them. The Nittos won't wear like the Michelins, but I intend to include the spare into the rotation mix, so that will extend the miles some. If Michelin made the 285/75/17 I would be all over them, but they don't.

dneilson - you said you too will go with larger tires "if the originals ever wear out". I know what you mean. I have an '04.5 with only 60,480 miles on it - the Michelins could easily go another 10 to 15 before hitting the wear bars. However, the tires are well over 6 years old according to production date, and we have some really HOT roadways here in Nevada, so it's about time to change out the originals.

That said, my other reason for going ahead and changing them out has to do with the RPMs I am forced to run at hwy speeds as a result of the 4.10 gears. Going to the 285/75s will effectively mean running the equivalent of 3.84 gears and drop the RPMs by nearly 200 at 70 to 75 mph.

With the torque curve of the CTD, a 4.10 gearset is overkill as long as one doesn't tow loads in excess of the truck's rated capacity - IMO.

dneilson - Yes, the 285/75/17 WILL FIT in the standard spare location under the bed on my 2004 - I have to think it will fit in the standard spare location on your '06. However, please don't take my word for it. A tape measure should provide you the answer.