wheels/tires/towing

Well I had a '99 1500 with 16" wheels and V6. It was rated to tow 8900 lbs.

Your 20's with a 3.92 is like towing with stock tires and a 3.55. The best permanent fix here is to regear the truck. Install some 4.56's (it is supported by ECM with reprogramming because some Power Wagons came with 4.56's) It will offset tire size and make it tow a lot better and ease strain on tranny. Do not take ratings as the gosphel as some do as there is little science behind them (mostly marketing). With 4.56 and 20's, you should be able to comfortably tow 8K or so without beating the tranny to death with down shifts and towing MPG will improve a bit too. When not towing your MPG will not take a hit because 4.56's with 20's and OD will yeild a low cruise RPM in OD. (It might actually increase MPG a bit under some conditions too)

----------------- The SnoMan

The 20 inchers he has are the same outside diameter an the 17's, I'd suspect, so gearing is NOT the issue, and there should be no gearing issues with brakes or ECU. I would NOT go to 4.56 gears at today's fuel prices! I'd stick with the 3.92 gears and forgo overdrive when towing. As for the tires, a good FIRM tread (likely not a M+S) with strong sidewalls is required. MOST of the 20 inch low profile tires are not a good solution for trailer towing for sidewall reasons (what sidewall? they are like a loll of friction tape) The best towing tire will be a compromise when it comes to ride (but so is a Low Profile performance tire) You want a tire that will not squirm, and a sidewall that will stand up and not buckle with sideloads. My recommmendation would be a good LT rated tire with a highway tread.17 inch would likely be the best. May well cost less for tires and rims combined than a suitable set of 20's to fit your current rims.

The "problem" with the 20's is two fold. First, the 20" tires are not rated high enough to tow/haul that kind of load. If you search around, you may be able to find some that are. LT truck tires don't come in a 20" rim size - yet. The second issue is the weight rating of the wheel itself. The 20" wheel is mostly for show, and may not be made strong enough for real work. The issue is NOT gearing. The overall diameter of the stock 17" and 20" package is the same. As I see it, you have two reasonable options. First, look around for a set of new 17" take offs. You'll probably be able to find a set with only a few thousand miles on them if you look around. Try an ad in your local paper or Thrifty Nickel. Second, don't worry about it. Your plans are for 1,000 pounds less than rated capacity. Even if your calculations are 500# off, you're still within specs. IMO, the rated capacity is fairly conservative anyway.

A factory 17" wheel will fit without a problem (as that's what they come with as standard equipment - you don't get bigger brakes when you opt for the 20" wheels). However, many aftermarket 17" wheels will NOT clear the brakes.

I agree with Bob... if it were me, (well, I wouldn't have gotten the 20's in the first place, but that aside), I'd opt for a set of factory 17" wheels, and get a good-quality load-range E tire (I'm partial to Michelin's - always had good wear/performance from them) in 245/70R17. That's just about a 31" tire, whereas your 275/60R20's are a 33" tall tire (and P-rated at that - meaning the sidewalls are much weaker than an LT-rated tire, especially an LRE tire). You'll need the dealer to re-program your computer for the different tire size, but that won't be a problem, because it's the stock size that comes with the 17" wheels.

I would absolutely NOT re-gear the truck... way too expensive, and decreased fuel economy when running empty. Since your tire/wheel combination is unacceptable for towing anyway, you'll get the same results by downsizing your wheel/tire combo as you would by stuffing taller gears in there.

You'll also be able to sell your 20's pretty easily, and offset a good portion of the cost of the new tires/wheels. When it comes time for new tires, you'll be saving even more, as the 17" truck tires are cheaper than the 20" rubber bands (probably save over $100 on the set).

That depends a lot on tire size on rim and if overall diameter is the same then the the rim is 1 1/2 inches close to pavement which is not good when you hit a chuck hole with a heavy load unexpectadly and loss a rim. You want more rubber between rim and road. On gear ratio, there is a false belief out there that taller gear equals better NPG towing and this is not true most of the time, especail with a gas motor that has a high RPM torque peak. There was a time when a 3.92 was a deep gear but that was when cars or trucks weight 4 to 5K and had 29 inch tires or so and no OD. Now they have 32's or so and can weigh over 6k before you load them up and have OD as well to boot. If you are that worried about MPG when not towing, buy a 4cyl to run around in. Also, deeper gear will improve towing MPG with a heavy load, not hurt it with a gas motor of that size as it is not the old low RPM stump puller that the old V10 was.

----------------- The SnoMan

You had a 1500 with a V6 that was rated to tow 8900lbs?? Yeah right. "GeekBoy" a écrit dans le message de news:

With 3.92 Axle Ratio Axle Ratio You Can Tow 7500 lbs Gross Vehicle Weight Rating (GVWR) = 6650 lbs Payload = 1321 lbs Curb Weight = 5329 lbs Curb Weight Front/Rear = 3103 lbs/3103 lbs GAWR Front/Rear = 3900 lbs/3900 lbs Gross Combination Weight Rating (GCWR) = 13000 lbs

if you air up to 44psi both tires can handle 5,202 (you noted 2,601 above per tire) your axles are rated 3,900 each. You will over load the axle before the tires. You are good to go.

But you can go with Avon Tyres (in the Cooper tires family) the Tech ST 275/60 R20 are a 119S tire rated at 2,998lbs. at 50 PSI.

Personal experience, I have not towed with my 05 Ram 1500 QC 4x4 HEMI

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Yeah right. It came right off the Dodge web site.