Automotive question sorta

[magusjinx]

How short can I make my driveline and still not bind the u-joint during normal suspension travel?

Automotive engine and tranny to matching rear end ...

I want to get them as close as I can and put the seating in front of the engine to put the least weight on the front wheel ...

[redneckray]

I have gone as close as 3 inches and still okay,[u-joint to u-joint]

[magusjinx]

And here I was worried about getting as close as 18'' ...

[Gorilla]

The Stallion looks like it is less than 18 inches but I have not measured it.

[alienhunter]

i also have been as short as 3" worked good

[Nauga Mok]

I've seen several drivelines on heavy equipment under 8". One was just the 2 yokes welded together making the joints about 5" apart. HE joints are considerably bigger than we use, so I wouldn't see anything wrong with 3" if properly aligned.

NM

[redneckray]

Also, when you make the driveline, don't for get to "TIME "them to make them work properly,

[FBTRIKE]

You probably know this, but I've seen it overlooked on many custom car projects. Make sure, that the angle of both u joints are the same. (The degree of bend) You can adjust this by tilting the axle. By have haveing both u joints at the same angle (although opposite to each other) it will help cancel out any driveshaft vibrations due to the u joints, especialy at sharp angles. Totally seperate from driveshaft balanceing. Length should not be an issue.

[magusjinx]

Just wondered because I didn't want the joints to bind if the rear end bottoms out on the stops ... I still wanna have a good 8 inches or so of travel up and down ... I like extra give ... I am also penciling up a gooseneck trailer design ... I figure hitch placement to be about a foot or so forward of dead center above the rear axle ...

Did I mention I might use the rear end off my 3/4 ton? ... A bit wide but what the heck ...

[Nauga Mok]

Goosneck hitch placement at 1 ft is too much ahead if the axel. Should be more like 4 - 6" depending on how heavy you want the front end. I think you'll find the gear ratio too low in a 3/4T rear axel. It'll give you lots of power, but it'll cut fuel economy & top end. Remember, you're not moving 8 - 10,000 lbs now, but more like 1,000 to maybe 1500 lb with all automotive parts. Rear gears can be as high as 2.75:1. You'll probably find the F250 rear is somewhere around 3.75:1 - 4.11:1 or even lower if it was a high GVW truck. 'Couse, now if you use realy tall tires --! Check the rear ratio on a GW or any of the shaft drive bikes & use a ratio that's close to what they use.

NM

[magusjinx]

Goosneck hitch placement at 1 ft is too much ahead if the axle. Should be more like 4 - 6" depending on how heavy you want the front end. I think you'll find the gear ratio too low in a 3/4T rear axle. It'll give you lots of power, but it'll cut fuel economy & top end. Remember, you're not moving 8 - 10,000 lbs now, but more like 1,000 to maybe 1500 lb with all automotive parts. Rear gears can be as high as 2.75:1. You'll probably find the F250 rear is somewhere around 3.75:1 - 4.11:1 or even lower if it was a high GVW truck. 'Course, now if you use realy tall tires --! Check the rear ratio on a GW or any of the shaft drive bikes & use a ratio that's close to what they use.

NM

F250 no mods ... 4.11 rear ... She does about 60 mph around 2800 rpm ... C6 automatic ... I figure I will be cutting gvw by at least 2,500 ... Thing is engine weight ... Diesels are HEAVY ... Mileage will go up a bit with weight reduction and exhaust mod ... thinking of either 8 singles @ 1 3/4" x 4' or a true dual in 3" x 4' ... Noise gonna make that decision for me ... Nice thing is I can run B100 with no mods ... ... I could probably mix 30w and moonshine ...

Should I narrow the rearend (track) or keep it stock because of long wheelbase? ... Probably 2 feet more than a Stallion ...

[stacebg]

good info here
Tom Wood's Custom Drive Shafts - Driveline 101

did some quick calulations with 8 in of travel if the trans and diff at same hight to start with and diff will move up 4 and down four, to be in the 7 degree area you need about a 33 in long shaft

if the trans is only 4 in above the dif now the shaft needs to be about 60in to stay at 7 degrees but if you go the 15 degrees you will be back to about 34 inch shaft

stace