What are you towing with your 2014?

[nando87]

I wish I could kick my fans on sooner without a Tune. I don't want to void my warranty if something does happen, especially since I'm getting Hot oil warnings already. Worst case I tune and get the fans to kick on and the problem doesn't go away and I blow my motor them I'm screwed!

[Jon A]

Really good info here: http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/17730894.cfm

 

I'd use some caution with that post though as much of its info is outdated.

 

One concern I have with adding rear axle spring rate before restoring front axle weight is that I would mask the front axle weight reduction by improving ride quality. I freely admit that I was chasing ride quality but my primary motivation was to stay within axle limits.

 

That shouldn't really be a concern though, that's the benefit. If testing shows a 50% FALR gives the safest handling and you can get good ride quality at that level, why would you want to increase that to 100%? If you already have a good ride and the safest handling, increasing the weight on the front further serves no purpose--it simply eats into your handling margin of safety.

 

 

Doesn't having a properly adjusted and sized wdh effectively provide increased spring rate to the rear axle?

 

Well, sort of but not really. The WDH can act somewhat as a spring but it’s being applied to the entire TV/trailer so it’s acting much differently than the suspension at one end of the truck. It sort of has a similar effect on ride frequencies but it’s much more limited. Even at 100% so the front is “acting like” it’s carrying the same weight as it was before you’re left with the rear basically carrying the full tongue weight—somewhere around a 50% increase in mass the rear suspension needs to handle. The only way to come close to making up for that is with increased spring rate in the rear.

 

And when I say “acting like,” etc, that’s really the crux of the problem. Despite their name, WDH’s don’t really distribute weight (much less mass), they simply add a new force (actually moment) into the system which gets reacted by other forces. So if you crank the WDH way over 100%, when you’re in a corner the front wheels really aren’t carrying that mass around the corner. All that mass is still behind the truck and it’s primarily up to the rear tires to keep it on the road. The extra downforce on the front tires just gives them more traction that they don’t need and takes away traction from the rear tires—where you really need it.

 

I understand that having the rear axle of a tv with too little weight can result in jack knifing. What is too little weight? I think it is very dependent on the on friction coefficient (and all those variables), drive axle weight and amount of trailer axle braking available.

 

Yes, what's "optimum" is going to vary from setup to setup. If you had your own test track and equipment you could likely come up with a different optimum % for every setup you tried. Of course, for any one percentage you're going to get better results in some tests and worse in others so even for one particular setup what's "optimum" is still going to be a compromise of sorts....

 

Short of that all you can really do is follow the manufacturer's recommendations. Now that we know they're actually passing SAE tests with their recommended setups we can have a little more faith in their recommendations than in years past. All the fundamentals are the same, the biggest setup difference you're going to have is a change in wheelbase.

 

WDH's are much more important and make a bigger difference with short wheelbase rigs. The same percentage FALR transfers a lot more "weight" to the front of a Yukon than it does to the front of a long bed crew cab. GM is still recommending 100% for Yukons as I suspect the 50% they recommend for the trucks simply wasn't enough to get acceptable steering response from them. On the other hand a long bed crew cab set at 50% is doing so little you might not even notice you have it, and since it's needed less that's probably OK. That sort of puts numbers to why longer wheelbases make for safer overall towing rigs, all else being equal.

 

As for weather changing things, I don't think that's going to be the case to any extent one needs to worry about. It's not a race car where you're worried about tire efficiency, overheating or contact patches with the tire distorted from cornering load, etc. Things are going to remain pretty linear and proportional. So I think the "optimum" setup on dry pavement is also going to be the best for slick roads. The big difference is you may be able to get away with a lousy setup on dry pavement and never know it because you stay so far below the limits of adhesion (hopefully) while on slick roads a bad setup is more likely to bite you.

 

I don't know how they've programmed the stabilitrak to combat sway. Hopefully they did a good job. It would be really interesting to talk to the guys who set it up. I haven't looked closely at SAE J2664 to see if it's deactivated for the tests but I doubt it since users wouldn't use the trucks that way. I do know mechanical anti-sway devices aren't allowed so technically they aren't needed to tow up to the max rating--but of course that doesn't mean they're a bad idea for an extra margin of safety. Stiffer rear springs/airbags also help reduce trailer sway.... ;)

[calgator73]

 

I'd use some caution with that post though as much of its info is outdated.

 

 

That shouldn't really be a concern though, that's the benefit. If testing shows a 50% FALR gives the safest handling and you can get good ride quality at that level, why would you want to increase that to 100%? If you already have a good ride and the safest handling, increasing the weight on the front further serves no purpose--it simply eats into your handling margin of safety.

 

 

 

Well, sort of but not really. The WDH can act somewhat as a spring but it’s being applied to the entire TV/trailer so it’s acting much differently than the suspension at one end of the truck. It sort of has a similar effect on ride frequencies but it’s much more limited. Even at 100% so the front is “acting like” it’s carrying the same weight as it was before you’re left with the rear basically carrying the full tongue weight—somewhere around a 50% increase in mass the rear suspension needs to handle. The only way to come close to making up for that is with increased spring rate in the rear.

 

And when I say “acting like,” etc, that’s really the crux of the problem. Despite their name, WDH’s don’t really distribute weight (much less mass), they simply add a new force (actually moment) into the system which gets reacted by other forces. So if you crank the WDH way over 100%, when you’re in a corner the front wheels really aren’t carrying that mass around the corner. All that mass is still behind the truck and it’s primarily up to the rear tires to keep it on the road. The extra downforce on the front tires just gives them more traction that they don’t need and takes away traction from the rear tires—where you really need it.

 

 

Yes, what's "optimum" is going to vary from setup to setup. If you had your own test track and equipment you could likely come up with a different optimum % for every setup you tried. Of course, for any one percentage you're going to get better results in some tests and worse in others so even for one particular setup what's "optimum" is still going to be a compromise of sorts....

 

Short of that all you can really do is follow the manufacturer's recommendations. Now that we know they're actually passing SAE tests with their recommended setups we can have a little more faith in their recommendations than in years past. All the fundamentals are the same, the biggest setup difference you're going to have is a change in wheelbase.

 

WDH's are much more important and make a bigger difference with short wheelbase rigs. The same percentage FALR transfers a lot more "weight" to the front of a Yukon than it does to the front of a long bed crew cab. GM is still recommending 100% for Yukons as I suspect the 50% they recommend for the trucks simply wasn't enough to get acceptable steering response from them. On the other hand a long bed crew cab set at 50% is doing so little you might not even notice you have it, and since it's needed less that's probably OK. That sort of puts numbers to why longer wheelbases make for safer overall towing rigs, all else being equal.

 

As for weather changing things, I don't think that's going to be the case to any extent one needs to worry about. It's not a race car where you're worried about tire efficiency, overheating or contact patches with the tire distorted from cornering load, etc. Things are going to remain pretty linear and proportional. So I think the "optimum" setup on dry pavement is also going to be the best for slick roads. The big difference is you may be able to get away with a lousy setup on dry pavement and never know it because you stay so far below the limits of adhesion (hopefully) while on slick roads a bad setup is more likely to bite you.

 

I don't know how they've programmed the stabilitrak to combat sway. Hopefully they did a good job. It would be really interesting to talk to the guys who set it up. I haven't looked closely at SAE J2664 to see if it's deactivated for the tests but I doubt it since users wouldn't use the trucks that way. I do know mechanical anti-sway devices aren't allowed so technically they aren't needed to tow up to the max rating--but of course that doesn't mean they're a bad idea for an extra margin of safety. Stiffer rear springs/airbags also help reduce trailer sway.... ;)

Check this... http://m.trailer-bodybuilders.com/archive/letter-editor-1

[calgator73]

Basically too little causes not enough steering authority due to not enough front load while too much transfer causes rear unloading which basically induces jackknifing due to tv oversteer.

[milligan]

Looking to get an enclosed trailer for tools and such. I've never shopped them before. Is there anything I should look out for when looking to buy?

[Vacheman]

Here's my little boat (14ft Grumman with 15hp Johnson).

 

[milligan]

Here's my little boat (14ft Grumman with 15hp Johnson).

 

 

I saw a few of the blue GMCs when I was shopping for mine. Both were 2WD and I was looking for 4WD, but I thought the color was neat. I was scared that I would dislike it over time though. I tend to stick to silver or white cars. I'm liking yours though.

[Vacheman]

 

I saw a few of the blue GMCs when I was shopping for mine. Both were 2WD and I was looking for 4WD, but I thought the color was neat. I was scared that I would dislike it over time though. I tend to stick to silver or white cars. I'm liking yours though.

Thanks. I almost got a silver Sierra, but it didn't have all the options I wanted. Silver, black, or blue are my usual car colors. Plus, the blue matches my boat pretty well (not that you can see it in the pic) .

[bdbake01]

From this weekend. ~400 miles, 13.6 mpg over some rather hilly terrain. Around 6klbs on the trailer, another 200lbs in the bed + 5 passengers in truck.

I'll have to say, I'm rather pleased. Overall, it was an absolute pleasure to drive. The 6.2 BARELY knew it was back there. Yeah, it's fairly aerodynamic as compared to, say, a travel trailer, but still. My old 4.7L Dakota struggled to get it up to speed. The AT didn't break a sweat in the least. In fact, coming back up the I-75/Cincinnati hill in the Dakota, I had to FLOOR it to maintain 65 mph. This rig, left it on cruise and it took the hill like nobody's business. It fiiiinally dropped a second gear for a few seconds at the top of the hill, but I seriously thought it was going to maintain in 5th alone.

 

The grade braking is fantastic. Going down the hill on the way up Friday, I never even touched the brakes and with the cruise set @ 65, it got up to 68. Very, very nice.

 

VERY stable, at no time did it feel unsteady. The only tiny complaint I may have after being overly critical is the front end might benefit from a bit more damping. Plenty of spring, but it bobbled a bit over very big bumps. Of which there were plenty as Ohio seems to have created some type of socialized economy based solely on road construction. Unbelievable. The trailer brake controller worked great as well. Easy to forget it's there, which is how it should be.

 

I started out using the tow/haul mode, and this just wasn't enough weight for it. The gears held waaaaay too long and all it resulted in was lower gas mileage and more noise. About halfway to my destination I turned it off, picked up at least .5 mpg. I don't know if it's the truck, tuning, engine or what, but this setup just does not need the tow/haul mode unless you are running quite heavy.

 

And did I mention the 6.2? OMG! This thing is a freight train. It felt like I could pull the coupler right off the trailer if I wanted to. It just does not give up. Torque out the wazoo. It's not a diesel, no, but a heck of a lot more fun IMHO. Just gets the job done! Very pleased.

[Cliff14Denali]

Well this past weekend I towed my 20' enclosed trailer with my Vette inside from NJ to Carlilse PA for Corvettes at Carlilse. The recommendations from this post helped alot. I put 45lbs of air in the rear tires, 40lbs up front then put 45lbs of air in the air bags. The porpoising was almost totally elimated. I was looking to put a WDH on it but will hold off for now.

[peejaykay]

Anyone towing 9000lbs with the 3.42/5.3 CC? Trying to determine if it makes sense to order the 2015 with 6.2/3.73/NHT or not. If I ever think about going heavier (larger camper) it's 3/4 territory.

[14SLTZ71]

Anyone towing 9000lbs with the 3.42/5.3 CC? Trying to determine if it makes sense to order the 2015 with 6.2/3.73/NHT or not. If I ever think about going heavier (larger camper) it's 3/4 territory.

I have never heard anyone who tows heavy loads complain about having too much HP or TQ. When in doubt go with the larger motor and lower gear ratio.

 

Edit: If you think you will need it, get it during the initial purchase. Don't end up wishing you would have done it. I am still learning that lesson.

[Panik]

From this weekend heading up to my mother in law's childhood home to do a bit of cleaning up. Couple of kids kicked in the tack room door in the barn and messed around. We figured if we did a bit of mowing and cleanup it might discourage folks from trespassing.

 

Anyways, trailer goes about 2,200 and the tractor is aroound 3,600 so with gear in the box the whole kit is likely in the 6K neighborhood. Truck and trailer combo worked well. The only thing I had to do was adjust the hitch height up a touch from the position it is in the picture.

 

I noticed a bit of bounce towing the trailer empty but absolutely none loaded. Trailer itself is 20' and rated to 10K so I could pull up to the 9,600 lbs the truck is rated for. However, in a reality, I doubt I would ever really want to do that, or if I did it would be a on a very infrequent basis. I love my truck and its capabilities but I think I would like to have a bit of "reserve" between the max tow rating and the weight of what I am trying to haul. *Just my personal opinion YMMV*

[BigBadSierra]

Just this popup but since we have the new truck we are shopping for a bigger travel trailer now.

 

Of course this on is 3000lb and 26 feet open, ha ha.

 

[bdbake01]

I have never heard anyone who tows heavy loads complain about having too much HP or TQ. When in doubt go with the larger motor and lower gear ratio.

 

Edit: If you think you will need it, get it during the initial purchase. Don't end up wishing you would have done it. I am still learning that lesson.

 

What he said. But, if you don't plan on towing it a LOT, then the 6.2 w/ 3.42 is more than sufficient I think. Why suffer the gas mileage and what not on the NHT if it's just for the occasional pull.