2500 6.7L w/ 6" Lift and 37s

[DrillerDave]

So guys I'm looking at this new 2015 2500 6.7L w/ 6" rough country lift and 37s. How well is the front end of these trucks gonna take the 37s? I ran 35s on my half ton for a long time without problems, so I imagine 37s on 3/4 ton running gear is no problem. I drove it two hours down the highway today from the main dealership to their branch in my town. I averaged around 115km/h didn't noticed any kind of wobbles when hitting bumps or any unwanted body's way in the corners. What are yours guys thoughts. This is going to be my first diesel and my first 3/4 ton.


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[SilverSurfer15]

Biggest factor is the wheel offset, what wheels do you have?

The further they stick out, the harder it is on the front end. Not really a concern in any offset for 9/10 inch wheels (IMO) but if you have x12s-x14s it could show wear much faster.

Assuming you have a normal wheel, you should be fine for 40-75k miles depending on driving style. Potentially more.

Couple little things that kill the front end... (sorry if you know this)

1) Dry steering. Don't do it. Its terrible.

2) Try not to full lock the wheel, especially in stressful scenarios. Ex. If you are going to bust a u turn, don't worry about it. But in a parking lot, don't crank the wheel all the way and try to keep inching forward or whatever. Just do a 3 or 5 point turn.

3) If you are going to go offroad or articulate the suspension, try to keep the wheels as straight as possible while making the initial impact. The truck itself does not need to be head on with the obstacle, but just try not to drive up onto things with the wheel turned all the way. It puts a lot of side load pressure on the tire.


Also you may want to invest in an adjustable track bar (if needed) and just make sure the alignment is right. A little preventative maintenance will go along way. And if you notice a problem, try to address it sooner than later. The longer something is bad, the worse the results become.

Conclusion: You will be fine. Common sense goes a long way. Id be more worried about regearing than replacing the front end.

 

[DrillerDave]

Well I don't think I need to regear for the 37s. Doesn't feel that much more sluggish then my friends stock 1 ton. It has 20x12 rims with 37x12.5 Mickey Thompsons


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[Wandell]

I only have 30k miles on mine, but so far no front end issues with 37's.

 

[SilverSurfer15]

the 12inch wheels aren't doing you an favors but I wouldn't be too worried about it. Just be smart, it will be fine. People run 37s and 40s on 12 and 14inch wheels on the dmax trucks with IFS lol. Just think.. you are WAY ahead of them lol. At least your wheel wont fall off

 

[brandonjansen]

You won't have any issues at all. I have an 8" BDS lift on my truck, ran 37x13.5 Toyo's on stock 17x7's with 2" BORA spacers for 30,000km and now have 37x13.5 Toyo's on 22x12 Forces for 13,000km. No issues at all.

I use my truck to commute +/- 80km a day mixed city/highway driving and it handles it fine. If you buy a good quality lift that's setup right and give the front end a few slight upgrades it will handle like a dream. My truck handles better now than it did stock. I can let go of my steering wheel at 110km/h and the truck will go straight for miles.

Lift wise I'd recommend looking at a few options besides RCX just for your own comparisons sake. Take a look at Zone and BDS and see what you think. Personally I would recommend them over RCX.
Steering wise I recommend a steering box brace (Hell Bent Steel) as it will keep everything feeling nice and tight with the 37's. I also run a dual steering stabilizer to help keep everything stable.

You may rethink the whole gearing thing once you get the 37's on there as well. Your truck has 3.42 gears stock which is definitely not ideal for larger tires. I couldn't even stand my 3.73's with the 37's so I swapped to 4.56's. Made the truck SO much better to drive, brought the exhaust brake back to life again, made 6th gear useful again, and is simply easier on the entire drive train. It's definitely something you want to consider doing. Most guys will tell you it's one of the best mods they've done when running larger tires.

 

[DrillerDave]

Well I'm sure they wouldn't hurt. But for as it is now is also okay. I don't hotrod my trucks around town. Go to work and back and pull the camper go out get firewood. I know towing will be affected with the big lift and tires. What are your guys opinions on towing a 25-30ft camper with the lift and tires. Obviously will be hard on fuel but that's besides the point. How is it for sway and handling. Travel trailer only I use my box to much for a 5th wheel.


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[SilverSurfer15]

My opinion... keep the truck in the right gear, don't try to be a hero and run 75-85mph, and remember braking might be sketchy if you get in the wrong situation. You will be fine, but the 3.42s are really going to suck in that scenario!

I used to tow a 24ft boat behind a HD on 37s, 6.0L with 4.88s, manually locked in 4th most the time at 45-50MPH ish. No problems. But I stayed off the highway. (mainly because gas motor and it screamed to maintain 55-60 on ANY grade lol)

 

[SilverSurfer15]

I couldn't even stand my 3.73's with the 37's so I swapped to 4.56's.

Im going to stray off topic for a second, you have probably been asked this before but is the 4.56 too much, do you think 4.10s would have been better?

 

[brandonjansen]

Well I'm sure they wouldn't hurt. But for as it is now is also okay. I don't hotrod my trucks around town. Go to work and back and pull the camper go out get firewood. I know towing will be affected with the big lift and tires. What are your guys opinions on towing a 25-30ft camper with the lift and tires. Obviously will be hard on fuel but that's besides the point. How is it for sway and handling. Travel trailer only I use my box to much for a 5th wheel.


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I find that with the size of my drop shank (around 11.5") it moves side to side quite a bit which can get a little weird feeling in corners. I plan to build some strut bars that go back to the frame off the bottom of it similar to the One Up Offroad drop hitch to help with that issue. Other than that it tows and handles no problem. Like Silversurfer said, keep your speeds reasonable and the truck in the right gear and you'll be fine. You are definitely going to hate the 3.42's if you hit any hills though.

Im going to stray off topic for a second, you have probably been asked this before but is the 4.56 too much, do you think 4.10s would have been better?

Depends on the type of driving you do. For the highway they're borderline too low. If I was doing more highway driving or we had higher speed limits around my area then yes, 4.10's would have been a better option. But for all around driving with a mix of city, highway, and towing I think the 4.56's were a great choice. Overall it feels great with that setup.

I've talked to a couple guys who have run 4.10's/37's and then 4.56's/37's and all say that they'd go with the 4.56's again hands down. They also give me the flexibility to run larger tires down the road if I please as well. There's a good chance 40's are going to end up on my truck at some point

 

[Ratket]

800 ftq and u want to run a taller gear???? if you are towing heavy a lot, sure. But in a daily driver scenario?? my buddy complains because he wants 321"s in his 12 ctd like ford runs in their power strokes.. It is deleted and tuned...but it is on a 6 inch lift with 37"s.. Is that truck brand new? don't bother changing the lift.. Make the dealer warranty it since u bought it from them that way. Then u are coverd.

 

[SilverSurfer15]

I've talked to a couple guys who have run 4.10's/37's and then 4.56's/37's and all say that they'd go with the 4.56's again hands down. They also give me the flexibility to run larger tires down the road if I please as well. There's a good chance 40's are going to end up on my truck at some point

Hmm that's interesting, thanks! As far as 40s go.... :********:

 

[DrillerDave]

I don't plan on going any bigger. In fact I may go down to a 35" tire after these are worn out. I use my truck to get firewood and the truck is pretty much as tall as it can be while still functional.


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[Ratket]

You are fine, did the dealer do the lift? If so make them warranty it for you.

 

[brandonjansen]

800 ftq and u want to run a taller gear???? if you are towing heavy a lot, sure. But in a daily driver scenario?? my buddy complains because he wants 321"s in his 12 ctd like ford runs in their power strokes.. It is deleted and tuned...but it is on a 6 inch lift with 37"s.. Is that truck brand new? don't bother changing the lift.. Make the dealer warranty it since u bought it from them that way. Then u are coverd.

The fact that they have a lot of torque is one of the reasons to run taller gears with larger tires. Sure the torque will turn them not problem but it's also MUCH harder on the drivetrain. Lugging the transmission at too low of an RPM and then giving it that 800 ft-lbs of torque through 3.21's and 37's is a great way to fry the internal clutches.

 

[DrillerDave]

You are fine, did the dealer do the lift? If so make them warranty it for you.

Yup. Truck had the lift,rims,tires on it before I ever showed up looking for a truck. All warranty. They are pretty good at warranty at this dealer.


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[DrillerDave]

The fact that they have a lot of torque is one of the reasons to run taller gears with larger tires. Sure the torque will turn them not problem but it's also MUCH harder on the drivetrain. Lugging the transmission at too low of an RPM and then giving it that 800 ft-lbs of torque through 3.21's and 37's is a great way to fry the internal clutches.

That is a very good point. What is the cost of a gear upgrade for these trucks to either 4:10 or 4:56, it would have to wait awhile as I'm sure it will be costly and I have to Christmas to start paying for so it might be a year or so to get gears depending on cost.


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[Ratket]

one guy on here has done a gear swap and he had a dealer do it. All aftermarket parts and since he had the dealer do it he got a warranty. Few others have had it done at drive line shops- but by by warranty on those axels. The dealer one was like 4500 and the drive line shop guys were like 2k. I believe 456 is the tallest you can go. I plan to do 456 in mine but it will be a while.

 

[brandonjansen]

That is a very good point. What is the cost of a gear upgrade for these trucks to either 4:10 or 4:56, it would have to wait awhile as I'm sure it will be costly and I have to Christmas to start paying for so it might be a year or so to get gears depending on cost.


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I paid just shy of $3000 CAD for mine including everything (parts - rings and pinions & install kits, labour, synthetic oil front and back, tax). You'll get it done for cheaper in the states though. Most guys that I've talked to who have had it done were in the $2000-$2500 range.