Thought on tires vs power vs...etc

[spicergear]

Bear with me on this at first-

So we've got 6.72's in the axles, and overdrive around .85:1 and NDT's at 38-39".
6.72, 39" tire, 55mph, .85 OD= 2,707rpm at 55mph.

Now slap on 46" XL's or XML's (for all the right reasons) and we end up here:
6.72, 46" tire, 55mph, .85 OD= 2,295rpm at 55mph. Okay now...stock trucks (this is not a knock on them) really aren't overlaiden with power and a big tire will make it seem like it has less power.

6.72, 46" tire, 55mph, 1:1 (3052 trans 5th)= 2,700rpm at 55mph.
Okay...so pissing in the wind? Large tires for MUCH more traction and better ride and weight loads. Same virtual rpm as a stock truck at 55mph. Now the kicker...a tighter spaced transmission to be able to run through gears and pull loads better.

*I used the .85:1 OD since that's a published od for the 3053 though other OD ratios have been listed...it's sort of for baseline of thought purposes.

Thoughts?

 

[BFR]

I actually like it, as these trucks (specifically their brakes and suspension) were designed with 45-50mph in mind.

 

[ken]

I think keeping the stock tranny then yank the air intake off and replace it with a round K&N strait on the turbo. Then crank the fuel rate untill it's at 1400 deg at WOT. That should give you enough power to overcome the new shoes. I canked my fuel rate 5 years ago and haven't had any trouble at all. These engines will make a lot of power as long as you watch the EGT's

 

[rmgill]

I think that regardless of how you configure the truck, you're better off driving these trucks with lots of room out front of you. What I did like about the trip is that I rarely had anyone slow in front of me. I think I must have passed two people on the way back.

Of course, there is the advantage that I know a cop isn't going to be pulling me over for busting the speed limit.

 

[ken]

I'm with ya ryan. The only time i got to pass someone was a national guard unit. I keep mine at 45mph and get in no hurry while driving it. Fuel cost too much and i've had a brake failure. So i keep it slow.

 

[BFR]

this looks even better if 1st gear on the 3052 is lower (numerically higher) than 1st on the 3053... anyone know how they compare?

 

[wallew]

It's funny you should post this now. I've been ruminating about this exact subject.

At what point does HP matter over gearing and tire size.

Granted, even if we can make better HP (say with a different turbo), we still have the gearing to overcome.

I have Michelin XDY-1's on my truck. They are 42" tall.

With the standard NDCC tires, my truck felt 'sluggish' in turns, etc.

Now with the new tires (inflated to 90 psi), she turns almost like she has power steering. As long as you are moving. Stopped is another issue entirely.

So, even with the K&N air filter (which I installed as soon as I got my truck) and the larger tires, I feel I can 'keep up' in traffic until I get to about 65 mph (60 mph showing).

I'm pretty sure that my fuel has also been turned up. Yet I consistently see about 10 mpg. Go figure. Of course, I rarely haul any weight other than the truck and myself...

GOOD POST.

jim

 

[Recovry4x4]

7.55 on the 3052 and 5.02 on the 3053A. I actually keep the 900x20 just for the reason of power. I can still do 55 all day and pass at 60MPH but the tie size keeps me moving up hills when dragging weight.

 

[spicergear]

One of the reasons I had brought this up was because of my big M715 (Velvet) that has Rockwells and 46" XML's on it. This truck has the 3053A and a 427 Big Block Chevy Tall Deck engine probably at 250-260hp...not gonna set the world on fire. I had driven this truck on the road with 1100x20 Goodyears and it did really well, even pulling an M105 with a Bridgeport J-head mill and a decent sized surface grinder in the bed. Since then, I've outfitted the truck with the XML's and changed (drivetrain wise) nothing else. I drove it last year (yeah, not real legally) 30 miles to the Carlisle All Truck Nat's. The truck was surprisingly down on power. It felt like I was pulling the 2300# M105 trailer. Still did okay but I had to keep a bit more pedal into it. Keep in mind that on POS6x6 brand wheels, the XML + wheel combo weighed just a fuzz under 250# each. That's 1,000# of rolling weight to overcome, PLUS the extra 12.5" per revolution further the big tire travels...and the friction (usually not considered) of the extra width/tread lugs.

Okay, so there's all that crap- then, I'm thinking of outfitting the crane truck (Blue) with the 46's and wondering it that's the best idea. I'm starting off over 4,000# heavier than a stock, yes I have about 85-90hp more but I can still see that getting eaten up with truck, load, long hill, OD and big tire extra OD. I may have a deal in a little while for some meaty 42"x 13" MT Continentals but wonder if for cheaper the 46" XL/XML and 3052 would be a better ticket?

 

[Recovry4x4]

Tom, if that works out with the 46" rubber and you've sacrificed all your gearing,sounds like the gasser tranny would work.

 

[rwelker]

thought on tires vs power...etc

Spicergear, I didn't know there was another green nut so close to me. I drive through Dauphin every day I go to work. Anyway, on the tires vs power issue, my duece is a work truck and I actually noticed better pulling when I went to 1100x20 from 900x20. Around here when loaded with 5-6 ton of stone I'm in the power band more (the manual states they will pull better at 1500-1900 rpm) and I don't have to shift as much. Unfortunatally my LD-465 which I turboed dropped a bearing about a month ago. I just finished installing a fresh LDS-465-1A and the difference in power is unbelievable. 2 gears higher on hard hills and much less exhaust noise. It's still tight and I'm sure it will get better. Everyone said I'll have overheating issues, but I put in a new radiator and haven't seen engine temps over 170 on 92 degree days. I need new tires and am considering 14.5r20 super singles over the 1100x20's. Rick

 

[spicergear]

Ah...you come down 225 to 322? After you come down over the mountain about a mile before the highway look for the for sale sign--that's my house. Truck farm is up 322 about 20 miles.

The 14.5R20's your looking at- are they in the 43-44" range? I'm pretty sure my buddy has a set of them on his Case 406 'Mog. I believe one of our especially talented guys here made up his own beadlocks and slapped those on too...along with a dump conversion.

 

[hot rod deuce]

I still like the more gear idea. Its making efficent use of the power you have. Heavy haul trucks dont just build HUGE motors. (well they do that too) Mainly they run 18 speeds with 2 speed axles. Thats a gear for every day of the month, grant it some over lap. Its like adding more turbo or roller rockers. Naturaly the rockers will FREE up power and out less strain on everything. I would bet if you had twice as many gears you would be able to out run the guy runnin 1400 on the pyro. Plus you can do it all day long. When you come to a hill (or at least i do) with the 5 speed one is too high and one is too low.

Now, i have a RT 613 from behind a 190 3208 that has the same Bell and input shaft as a multi-fuel. Same clutch size two. Its just double. With a little more work your crane truck could have 13 gears. Do a little more work on the shifter and you can have an 18 (just make it split the bottom) Swap the splitter gears around and now you have an overdrive. (or just go find an RTO) dont forget the two speed transfer. BANG 32 forward gears and 8 backing up (with some overlap) Best part is that they are cheap!

 

[Recovry4x4]

How much longer is an RTO-613 and define cheap in dollars? Also are they synchro trannys?

 

[spicergear]

Man you're full of good ideas HRD!!! Hmmmmmm...

 

[Trango]

I want to say that a 610 is somewhere around 36 from bellhousing to center of u joint.... somewhat of a big tranny. It's a sure thing, with the stock engine, that you'd be moving your transfer case back if you swap to anything bigger than the Spicer 3000 series units that come stock.

I currently have an old NP435 and also a T18 I picked up for you don't want to know how cheap. These trannies are not much smaller than the stock deucers!

If memory serves correctly, a 610 will weigh in around 400 lbs.

By the way, the coolest thing about these big trannies is that they are AIR SHIFT. Yeah, buddy!

Bob

 

[hot rod deuce]

You are very right, they are big BUT BUT BUT the actual 5 speed portion is no bigger than what we already have. It just has two two speed spliters. if you take them off its not much bigger. About the size of 2 205 T-cases bolted on the back. 38 inches Front of bell to center of yoke. A 610 may be a better choice you just give up the splitter for the top 5 gears. If memory serves me right, low gear in around 8:1 or so plus an OD but low/od can be swaped around. IE either have a LOW LOW hole or and Over drive. an RTLO and RTO can be the same but with the splitter gears swaped for the OD. Most RTO's have the OD in the main box (just like our spicers)

when i say cheap i mean i got mine for free they can be had for around 100 bucks at the right place. A scrap yard might want 700 bucks for a good RTO if your in the big city.

Huh thats funny,I thoguht you had all the good ideas!!

Ever thought of a cheap Allison AT-545 and a 3 speed brownie box? I guess you guys might not have the room but i have an extra 4 feet to play with

Does any one know any thing or any body that knows anything about allisons? I think i finaly decied or a 6 speed OD with lock up.

 

[mangus580]

what Allison auto would a Chevy C-50 with a 350 engine have had?

 

[Recovry4x4]

Mike, I'm guessing an AT540 or the AT 545 depending on year.