Customer Max Trailer Weight

[travelingjw]

Prior to purchasing my TT a truck mechanic did a mod for me. Being a newbie, I "understood" the explanation at the time. By changing the rear end to a "heavier" rear end I was safe to purchase the trailer I wanted. Jyaco 23MRB. Now I am planning some long distance travel and want to make sure that we are safe. I have followed Doug's and Crabman discussions but still cannot figure out how to calculate my actual numbers with the mod.

I have a 2013 Chevy 1500 Express Van: 5.3 V8: Stock Maximum trailer weight is 6,200 with a GCWR of 12,000 lbs.

The mechanic replaced the rear end with a 2500 rear end. With a 4.8 V8 (smaller than mine) max trailer weight is 7400 lbs with a GCWR of 13,000 lbs.

Mechanic told me that with my 5.3 V8 (even though a bit bigger) I should stick to the GCWR of 13,000 just to be safe.

Since the gear ratio is the same for the two different trucks (1500 and 2500) I am confused as to what affects the different calculation with a smaller motor. Is it only the weight of the vehicle (I don't think so). It must have something to do with a "stronger rear end," but I don't see any reference to that anywhere.

Some guidance would be helpful as we are planning on visiting the Tetons and some other high mountain ranges.

[LiftedAWDAstro]

If the new 2500 rear axle the mechanic swapped in, does in fact have the same gear ratio as the stock 1500 rear axle then you really have gained nothing in terms of towing capability. In fact you are less capable now due to the "new" rear axle being heavier. What you have gained is a stronger rear axle to handle the weight. The 2500 axle probably has bigger brakes and should have bigger axle bearings. Did he swap in the 2500's leaf springs? If so, that will help with handling the weight of the van, cargo and trailer tongue.

How much does the van weigh all set for camping? Subtract that from the 12,000 GCWR and that will be the max trailer weight you should tow. I would not jump to 13,000 GCWR simply due to a heavier rear axle with the same as stock gear ratio.

[Parcany]

I agree with Lifted. The only other thing I see is now you have to have 2 different rims with tires on for spares. 2500 should have 8 lug rims and yours should have 6 lugs rims. If they just changed the rear end with the same gear ration than you actually have lost some weight carrying capability. Cause the 2500 axle will weigh more than the 1500.

[travelingjw]

Thanks to both of you. I will check with the mechanic tomorrow to get the specs. He specializes in trucks and immediately knew the issue when I explained. We now have a van with 6 lugs in front, 8 in the back, and have to carry two spares. When I gave him the stock van specs and the trailer weight he ran the calculations and the the new gearing will be enough. I will still go weigh it all just to be sure.Thanks again.

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[travelingjw]

Called today and he was way ahead of me. He installed lower gearing, beefed up the suspension, installed extra bumpers. He calculated the impact and I have about a 15% safety margin if I travel with all 3 tanks full, no extra people or weight; though he cautioned me against it. His advice was to never travel with the black/grey tank more than 1/3 full and keep my weight down. Suspension set for up to 500 lbs above highest possible weight with the equalizers (tongue weight, etc) which includes extra passengers in the TV. He said that since the calculation had to be done by his engineer, it is not something he would recommend I do over and over; just keep the TV under 4 people or under, don't put extra weight in the TT, and don't travel with full tanks. He concluded that full tanks and 4 people would drop my safety margin below 11% which he considers not acceptable. He read your comments and had high praise and followed with he does this for a living, every day and he would never sell something that was unsafe. (He also said to mention that I gave him the specs of the MRB before he agreed to complete the modification).

[norty1]

You have a one of a kind setup!

Let us know how it preforms.

[travelingjw]

So far it performs great! Just completed our 4th trip. No problems going up, going down at 6% grade we are in good shape. 7% and above the front brakes will start to heat up if the grade is over 4 miles or so. (I had upgraded brakes put on the front but they still will heat up; only experienced one 7% grade that was over 4 miles with no "hills" to rest up). Running through a valley yesterday we hit some wind, maybe 25 - 30 MPH. No problem at all and virtually no sway; it affected the van but I am used to that. Talked to a racing buddy of mine today who has had toy haulers all his life as I wanted to check and double check but he confirmed that with the oversize rear end that I will be in good shape. He laughed when I told him about the 8 lug in back and 6 in front but when I told him it was my wife's van, he knew. I think the real test will be when we hit Yellowstone and the Teton's next year but my answer to "everything" is slow down and just be safe....that's what I call retirement. Live long and have fun.

[LiftedAWDAstro]

Glad to see he installed lower gears and beefed up the suspension! He is also correct in that you should still limit your GCW by limiting the cargo in the van and the TT. You may want to look into a better transmission cooler if there isn't already a good sized auxiliary one from the factory. Do you have a transmission temp gauge?

[travelingjw]

Thank you. The cooler is already installed. The temp gauge is a good idea to investigate.

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