What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Tire Size/Gear ratio/Tranny questions

handloader90

handloader90

Building!
Joined
Sep 14, 2013
Posts
2,665
Reaction score
1,053
Location
Colorado
Hey fellas,

Prepping to swap an NV4500/NP241 w/ SYE into my K20.

I've got an 8 lug D44 up front with 52's and crossover. 14BFF in the rear with discs and a detroit. Both axles 4.10 geared.

Currently on some well worn 315 tires, measure out to 33.5" tall.

Planning on keeping the D44 open. Planning on slotted rotors and some good pads front and rear.

The NV4500/241 will be behind a real healthy 6.0 gas engine.

Truck is my DD for most of the week, hits the trails too. Planning on the truck being a hauler, towing vehicles, hauling parts etc.

Planning on trying to find a true 35" tire once this swap happens. Planning on sticking with the D44 up front due to the current going rate of any kingpin axle.

What say you about towing with 4.10's, 35's and an NV4500? Do I need to toss some 4.56's or 4.88's in my axles?

Also, what is everyone's opinion on towing in OD? I've heard that it's fine and I've heard people say don't forking do it at all.
 
handloader90 said:
Hey fellas,

Prepping to swap an NV4500/NP241 w/ SYE into my K20.

I've got an 8 lug D44 up front with 52's and crossover. 14BFF in the rear with discs and a detroit. Both axles 4.10 geared.

Currently on some well worn 315 tires, measure out to 33.5" tall.

Planning on keeping the D44 open. Planning on slotted rotors and some good pads front and rear.

The NV4500/241 will be behind a real healthy 6.0 gas engine.

Truck is my DD for most of the week, hits the trails too. Planning on the truck being a hauler, towing vehicles, hauling parts etc.

Planning on trying to find a true 35" tire once this swap happens. Planning on sticking with the D44 up front due to the current going rate of any kingpin axle.

What say you about towing with 4.10's, 35's and an NV4500? Do I need to toss some 4.56's or 4.88's in my axles?

Also, what is everyone's opinion on towing in OD? I've heard that it's fine and I've heard people say don't forking do it at all.
Click to expand...
I will tell you this:
To get the right ratio for a 35" tire you should have 4.56
But with a healthy engine and a manual transmission you can tow with 4.10
I had 3.08/35"/sm465/205 with a 5.8 turbo diesel and had no problem doing anything, towing a truck on a trailer, daily driving, rock crawling... I just wished I had overdrive
 
I figured I would need more gear. I've got some 4.56's and the correct carrier for the 14 bolt in my garage.

Just need to pick up some thick cuts for the front.
 
imiceman44 said:
I will tell you this:
To get the right ratio for a 35" tire you should have 4.56
But with a healthy engine and a manual transmission you can tow with 4.10
I had 3.08/35"/sm465/205 with a 5.8 turbo diesel and had no problem doing anything, towing a truck on a trailer, daily driving, rock crawling... I just wished I had overdrive
Click to expand...
The 6.0 that's going in has the higher flowing "243" heads from GM, 224/230 112 LSA cam with all the right springs and hardened retainers and such. From the info I've gathered it should push 400+ HP in the higher RPM's and I should lose much of that due to parasitic loss.

The cam may be too much, I think it's aimed towards top end (I'd rather have low end grunt) but I got it for dirt cheap with the springs. Gonna try it out, if it's not doing what I want I'll get a different one.
 
Last edited:
handloader90 said:
The 6.0 that's going in has the higher flowing "243" heads from GM, 224/230 112 LSA cam with all the right springs and hardened retainers and such. From the info I've gathered it should push 400+ HP in the higher RPM's and I should lose much of that due to parasitic loss.

The cam may be too much, I think it's aimed towards top end (I'd rather have low end grunt) but I got it for dirt cheap with the springs. Gonna try it out, if it's not doing what I want I'll get a different one.
Click to expand...
I only had 180 hp but 410 ft.lbs of torque at 1000 rpm.
How much tq do you think it will have at 1800-2000 rpm?
 
imiceman44 said:
I only had 180 hp but 410 ft.lbs of torque at 1000 rpm.
How much tq do you think it will have at 1800-2000 rpm?
Click to expand...
I honestly couldn't tell you. I don't plan on spending the money on a dyno either so I'll probably never know for certain.
 
handloader90 said:
The 6.0 that's going in has the higher flowing "243" heads from GM, 224/230 112 LSA cam with all the right springs and hardened retainers and such. From the info I've gathered it should push 400+ HP in the higher RPM's and I should lose much of that due to parasitic loss.

The cam may be too much, I think it's aimed towards top end (I'd rather have low end grunt) but I got it for dirt cheap with the springs. Gonna try it out, if it's not doing what I want I'll get a different one.
Click to expand...


The cam with the high altitude is going to be a bit doggy below 2500-2600 rpm, you will be a lot happier with about 10 degrees less intake duration and your fuel mileage will be a lot better with a little wider lsa. Anything you can do to help low speed torque will be worth while including long tube headers, gen 4 intake etc.

What lift does the cam have? If it's over about .560" I would highly recommend not running it in this application as valve train durability can become a bit of an issue with the prolonged higher engine speeds that it will see when towing.

If you have 4.56 stuff then run them, if you have to buy gears 4.88s will be better.

If the motor will pull overdrive then run it in overdrive, the 6.0 is not making enough torque to ever hurt a nv4500.
 
My opinion. 4.88s. The motor you described with a too big cam will have zero issue spinning at 3k all day long . The LS is still yawning at that rpm. Nothing will give you power like mechanical advantage.

Myself I'd probably do 5.13s.
 
bigblock72 said:
The cam with the high altitude is going to be a bit doggy below 2500-2600 rpm, you will be a lot happier with about 10 degrees less intake duration and your fuel mileage will be a lot better with a little wider lsa. Anything you can do to help low speed torque will be worth while including long tube headers, gen 4 intake etc.

What lift does the cam have? If it's over about .560" I would highly recommend not running it in this application as valve train durability can become a bit of an issue with the prolonged higher engine speeds that it will see when towing.

If you have 4.56 stuff then run them, if you have to buy gears 4.88s will be better.

If the motor will pull overdrive then run it in overdrive, the 6.0 is not making enough torque to ever hurt a nv4500.
Click to expand...

Here are the specs on the cam. I don't mind switching to a different cam though. Picked this one up for extremely cheap with the springs and retainers and such, package deal with the 243 heads.

20180928_152113.jpg
 
handloader90 said:
Here are the specs on the cam. I don't mind switching to a different cam though. Picked this one up for extremely cheap with the springs and retainers and such, package deal with the 243 heads.

View attachment 279574
Click to expand...
Just advise.
If you aren't planning on racing this truck or having fun burning rubber, this cam is the last thing you want on this engine.
I would rather have a stock cam instead.
But of course if you want to improve look for an rv type cam, where the tq wakes up early.
 
A mild cam will really wake up that motor.

With it out I'd do one of the milder cams and call it good

But I'd still gear to 4.88 at least
 
Thanks for all the input fellas.

4.88's in a Dana 44 on 35's won't be prone to breaking?

Would you recommend thick cut front and rear? Thick cut are a little stronger than regular ones?
 
IMHO, 4:88s are going to be perfect for 35" tires. If you plan on going bigger in tires, then regear to 5:13s. As far as the cam, as stated earlier, go with an RV cam. Better low end torque. Your torque specs will be about right for towing and fuel usage.
 
wheels87k5 said:
IMHO, 4:88s are going to be perfect for 35" tires. If you plan on going bigger in tires, then regear to 5:13s. As far as the cam, as stated earlier, go with an RV cam. Better low end torque. Your torque specs will be about right for towing and fuel usage.
Click to expand...
What is an "RV" cam? Just a cam that promotes the most torque?
 
My recommendation is to just keep the 4.10's for now and see how it does. If you don't like them you can change them later. The 4.10's will probably be better for the daily driving aspect and should be perfectly fine for off-roading. I have a 2500HD with a stock 6.0L and 33" tires and to be honest I think the engine is running pretty high RPM's when cruising down the highway empty....at least a higher RPM than what is needed. For towing you can always run in 4th gear instead of OD......again, with the 4.10's and 33-35" tires you could spin the engine at whatever RPM it is at on the freeway forever.

A couple comments I always make:
- there is not much difference between 4.10 and 4.56 gears....if you have all or most of the parts already and can do the work yourself it's not that big of a deal, but no way I would shell out the $ to buy all new parts and then pay a shop for the labor to do this
- in this situation the lower gears are only for the road driving and towing aspect. Since you will already have a good crawl ratio with the 1st gear of the NV4500 and low range of the 241 a couple steps lower in the axle ratio is not going to make a big difference off-road, rather they are to get the engine rpm in the right range when cruising the freeway
- gear the vehicle for what it spends the majority of time doing......if you mainly DD an empty truck on the freeway I'm not sure you want 5.13 gears on 33-35" tires. While I agree it would be nice for acceleration and such they are probably not the best for fuel economy, noise, etc... on the freeway.
 
6.2Blazer said:
My recommendation is to just keep the 4.10's for now and see how it does. If you don't like them you can change them later. The 4.10's will probably be better for the daily driving aspect and should be perfectly fine for off-roading. I have a 2500HD with a stock 6.0L and 33" tires and to be honest I think the engine is running pretty high RPM's when cruising down the highway empty....at least a higher RPM than what is needed. For towing you can always run in 4th gear instead of OD......again, with the 4.10's and 33-35" tires you could spin the engine at whatever RPM it is at on the freeway forever.

A couple comments I always make:
- there is not much difference between 4.10 and 4.56 gears....if you have all or most of the parts already and can do the work yourself it's not that big of a deal, but no way I would shell out the $ to buy all new parts and then pay a shop for the labor to do this
- in this situation the lower gears are only for the road driving and towing aspect. Since you will already have a good crawl ratio with the 1st gear of the NV4500 and low range of the 241 a couple steps lower in the axle ratio is not going to make a big difference off-road, rather they are to get the engine rpm in the right range when cruising the freeway
- gear the vehicle for what it spends the majority of time doing......if you mainly DD an empty truck on the freeway I'm not sure you want 5.13 gears on 33-35" tires. While I agree it would be nice for acceleration and such they are probably not the best for fuel economy, noise, etc... on the freeway.
Click to expand...
That's pretty much what I was saying.
Use what you got for gears later if it's not good enough you can still change it
 
You must log in or register to reply here.

Latest Posts

Top Bottom