looking to change my axle ratio

Hmm interesting....


Considering a direct drive 10 speed actually has a lower granny gear....

 

Depending on model, yes. The C model has the deepest low gear IIRC, and the B may be the same. No 18 speeds available with the "C" ratios I dont think. This is where the rear end ratio comes into play,. get it yet Dad?
The thing to look at though, while Google is your bestest fwend, is the step % between those mega 10 gears. Then compare to the step between the 18. Also have a look at Eaton's own recommendations regards transmissions and hauling weight. Only thing that super duper 10 speed gets the nod on, is 80k lb freight hauling loads. Not a very versatile transmission if you ask me, but what do I know....

Martin

 

Here is something that you may or may not be aware of. Eaton's direct drive transmission is only rated at 1550lbft. Now they say in their literature that 200lbft can be added to the top direct model, but that is only in the top 2 gears. To go to a 10spd that is rated for 1650,1750, or 1850 your only option is for it to be an overdrive. I don't know about you but a transmission rated for only 1550 is not going to cut the mustard.

 

The 10spd step is around 34% with some fluctuation +/-

The 18spd step is around 17% with some fluctuation +/-

 

That has nothing to do with direct vs. overdrive, but rather 10 speed vs 18 speed.


So now we understand that the transmission DOES affect startability.

I'll be ######.

 

Yup they're limited in power, volvo goes to 1950 I believe. That's why they should be 80k max operations. It's not because they suck going up hills.....

 

I don't recall him or anyone else for that matter saying that it didn't, we have been more focused on the gears out back, but since you seem to want to keep dragging transmissions into it, we are finding the week spots/points with those as well.

 

YYAAAWWWNNNNN.
So does a doubler, so does the grade, so does the weight, and so on.
Lets all get a 50:1 first gear transmission and focus on one thing.
Or, we can get an overall good transmission and do lots of things.
Or maybe, just maybe, we can get some reasonable rear end ratio's in there and then drive down the road all happy.
You can keep your weak 10 speed direct (from the sounds of it). You can keep those stupidly tall rear ends that focus on not being able to climb a mountain but cruise at your governed 62mph, and the rest of us shall get on with life with a chuckle.
Dont let us down now, come back with some more, please?
Martin

 

That's the problem you're too focused.

Now we agree a 10 speed 3.55 setup is an acceptable setup? Not too fancy, and I wouldn't want to haul anything serious with it right? Thousands of trucks like that going down the road doing just fine. The startability is acceptable, the gradeability is acceptable, etc..

Low gear is 39.263 overall ratio (11.06 X 3.55)

High gear is 2.6625 (.75 x 3.55)

34-35% steps between each gear

We could all drive a setup like this and not really be that all unhappy. Would it go up the hills fine? Would it start out fine? Absolutely.

Do you gentlemen agree with this?

 

I did like 12 pages ago