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Premium Member
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Discussion Starter #27
Really glad you guys brought up driveshaft angles. Spent the last few days checking driveshaft angles at several scenarios and this is what I found.

Originally took measurements based on the axles at full droop, both shocks being fully extended:

Front Driveshaft (two piece shaft, only way to clear lower suspension mounts)
@ 16": 25deg
@ 15": 22.5deg
@ 14": 20deg

Rear Driveshaft
@ 16": 30deg
@ 15": 27.5deg
@ 14": 25deg

Those numbers concerned me based on what the interwebs says for u-joint maximum angles: 1310's are good to 30deg, 1350's to 20deg, and 1410's are 35-37deg. My D300 has stock 1310 yokes front and rear. My 14 bolt currently has a 1350 yoke and my D60 currently has a 1310 yoke. Wasn't able to find good info on what the various series CV joints can handle. I did come across this info on the JE Reel website in regards to their 1350 CV joint, "Stronger than our 1310 style shaft and takes you from a 26* C.V. angle to a 32* C.V. angle. So are 1310 CV's good to 26deg and 1350 CV's good to 32deg?

Then I decided to look at the numbers if I were to add a center limiting strap, so driveshaft angles if one side of the axle was at full droop and the other was at full stuff.

Front driveshaft @ 16": 22deg
Rear driveshaft @ 16": 15deg

Also how much full, even axle droop I could get before hitting the 20deg mark (assuming I was going to upgrade to 1350's).

Front driveshaft: 5.5" of droop
Rear driveshaft: 4" of droop
...Not real excited about those numbers.


Options I see at this time...1) Run 1310's every where and limit axle movement. Least cost option as I dont have to upgrade the D300 at all. 2) Looks like maybe I can upgrade the D300 output yokes to run 1350's without upgrading the output shafts (yes the output shaft would be my "fuse"). Run a 1310 front and 1350 rear, or 1350 front and rear. Limit axle movement 3) Upgrade the rear output to the heavy duty 32 spline, 1350 yokes, and 1350 driveshafts. Is it worth it to run 1350's at all? Simple answer is yes for the strength but is it worth it? Also when its it recommended to use CV joints in driveshafts?

That's where I'm at with suspensions and driveshafts
 

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Life=Short. Jeeps=Cool
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3,883 Posts
Just an FYI, they do make conversion joints that are 1310 on two sides and 1350 on the others. I've been running them in my tj with no issues.

Sent from my SM-G960U1 using Tapatalk
 

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throttle jockey
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1,656 Posts
Another fyi, stock superduty front dana 50 yoke will fit the stock dana 300 output shafts and have 1350.
 

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Premium Member
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4,452 Posts
Discussion Starter #30 (Edited)
Just an FYI, they do make conversion joints that are 1310 on two sides and 1350 on the others. I've been running them in my tj with no issues.

Sent from my SM-G960U1 using Tapatalk
:thumb:

Another fyi, stock superduty front dana 50 yoke will fit the stock dana 300 output shafts and have 1350.
Nice! I'll snag that off my D50 if I end up going that route. I'd hate to risk grenading a D300 output but maybe it makes sense to swap that to the output, run a 1350 rear shaft, and then upgrade the output in the future.

Or use that D50 yoke on the d300 front output so the front can be 1350 as well.
 

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Premium Member
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Discussion Starter #31
After double, triple, quadruple checking things, mocking things up, cycling the suspension more times that I can remember, I've got a couple of updates...

Shock lengths. I think I'm going to stick with 14" coilovers. I was able to make room for a little more up travel so I'll plan on running them 6" of up travel and 8" of droop. While mocking up the rear I realized one of my chassis tubes is in a bad spot to package the coilovers so the chassis will be going under the knife here in a little bit for minor tweakage :sonicjay:

Driveshafts. Plan is to run a 1350 double cardan rear shaft for the extra angles the double joint allows. Also just makes sense to run something larger than 1310's with all that I'm doing with this build. I'm going to run the stock D300 output shaft for the time being, until I can justify (and afford) upgrading the D300. Front driveshaft is going to be a two piece 1410 with single joints. I couldn't find an "off the shelf" way to run a 2 piece with a 1350 double cardan joint in the middle so the 1410 single joint shaft will give me the angular movement I need.

I also took final measurements of where the 4-links ended up and I'm at about 95% anti-squat in the rear, 75% in the front. Not sure how I feel about that 95% in the rear. Easy solution would be to lengthen my lowers but I'm tempted to just run it as is and see what happens. From what little I know 95% isn't ideal but maybe it will be for me :sonicjay: And if it ain't broke don't fix it :d:

Immediate plan is to rework some tubes on the rear of the chassis, get at least the rear driveshaft on order, add more tubing for the coilover mounts and other areas, and figure out how I'm going to mount the seats.
 

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LCG HIJKLMNOP
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7,815 Posts
I've broken 2 1310 cv rear driveshafts without having to replace the D300 transfer case. I'm still on the original 1310-1350 conversion joint. Might be something to consider. Both times it wouldn't have mattered what size they were, they would have been broken. I twisted the shaft itself right off from torque on the last break. I was back up and wheeling an hour later (the next morning to clarify). Try that with a broken tail shaft in the t-case.........
 

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Low Range Drifter
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8,114 Posts
Years ago after messing around with 1310cv and breaking them, and moving to combo joints and busting them, and after getting made fun of by the misfits I followed their advice and built 1410 non-cv shafts.

They have held up so much better. The angles aren't an issue. Easier to sleeve the rear shaft to make it heavy wall and a battering ram.
 

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LCG HIJKLMNOP
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7,815 Posts
Years ago after messing around with 1310cv and breaking them, and moving to combo joints and busting them, and after getting made fun of by the misfits I followed their advice and built 1410 non-cv shafts.

They have held up so much better. The angles aren't an issue. Easier to sleeve the rear shaft to make it heavy wall and a battering ram.
What transfer case were you running?
 

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Premium Member
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Discussion Starter #38
Cage question. Way back in the early stages I made a decision on the cross bracing on my b-pillar to not bring them to a single node. Regret that now :( No good way to redo things so trying to figure out a good way to move forward. I was thinking of placing the upper tubes in red, adding an additional tube below to strengthen the joint (the blue tube), and then could even fill in the area between the horizontal cross tube with plate steel (green). Thoughts?

 
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