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When do you need to go to a rear CV style driveshaft...

mrdrinksalil

mrdrinksalil

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I am trying to decide If I should get a CV style driveshaft or not. I am running a TH400/205 in an 85 K5 frame w/a 14 bolt. 56" springs giving +4 wheelbase and DIY4X shackle flip w/ 6" shackles. Anyone running similar setup that can give me their opinions?????!!!:confused:
 
Don't know about cv drivelines but I would suspect that if you pinion is at the Tcase and you can afford it I would go CV.

On a side note have you had gas tank to axle clearance issues with the 14FF moved back 4"? I have heard that the diff cover likes to become close and personal with the gas tank in this configuration.

Thanks

Dik
 
when it would be needed is if you have so much lift, your joints are binding in the standard shaft position.
 
obijuan said:
when it would be needed is if you have so much lift, your joints are binding in the standard shaft position.
Click to expand...

Well if you're building a truck and you have to buy a driveshaft it isn't really smart to buy a NON CV and find out you needed one now is it?
 
Pull a peice of string or something from yoke to yoke and figure out what your angles are going to be. If they are within the limits of a non cv then stick with that, if not get a cv. If its close then I would go with a cv, also depends how fast you want to go to I suppose.
 
i wanna say 28?

if i had about a five to six inch lift they would bind.
stock blazer diveshafts are clearanced for more angle but are smaller joints.
 
At a 4 inch all spring lift, it didnt bind, but u-joints didnt last long. every few trips I would break the front u-joint on the rear driveline. Pain in the a$$ with a slip yolk on a holiday weekend with no parts stores open. Gotta love AAA.
 
The C/V is to get rid of vibrations, not to allow more operating angle. So the big question is how much vibration you can live with. If you drive on the highway a lot, it's a big deal.

Yes, there are some big-$$ C/Vs now that can take a lot of angle, but in general, a standard 2-joint shaft can operate at a larger angle than a C/V shaft. Spicer rates most of their joints at 3-5 degrees operating angle (for full warranty, etc.). That is impossible with a lifted Blazer. You can keep a 2-joint shaft smooth up to 10 degrees if you set everything up right. Even a 4" lift might put you out of that range. You can probably drive on the highway with 15 degrees in the joints, but you will be feeling it.

To bind the joint will take a lot more angle. The angle needed depends on your height and flex.
 
If you have a regular driveshaft now, and its not eating joints or giving you noise/vibrations on decel, I would say you are ok. Having the axle pushed back helps. Is your tcase dropped? Is your rear pinion rotated up?
 
Leper said:
If you have a regular driveshaft now, and its not eating joints or giving you noise/vibrations on decel, I would say you are ok. Having the axle pushed back helps. Is your tcase dropped? Is your rear pinion rotated up?
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My Tcase isn't dropped and lowering it isn't an option because the 205 allready hangs too far below the frame rails for my liking. As for the pinion angle, its set-up close to perfect now for a non CV. For a CV I would have to rotate it up some more.
 
im gona run a cv with 7-8" lift and the rear axle back 3.5".

if the pinion angle is decent you might be alright without a cv, i know i ran 9" lift with the axle 2.5" back and pinion tilted up a good bit and didnt have that much vibs up to 75mph, but i didnt plan to go cv eventually.
 
mrdrinksalil said:
I am trying to decide If I should get a CV style driveshaft or not. I am running a TH400/205 in an 85 K5 frame w/a 14 bolt. 56" springs giving +4 wheelbase and DIY4X shackle flip w/ 6" shackles. Anyone running similar setup that can give me their opinions?????!!!:confused:
Click to expand...

I have the exact same setup.

I just ordered a cv from Jesse, why waste teim and money on anythign less... :wink1:
I went with the flange at the 205 as well,
 
reddog64 said:
I have the exact same setup.

I just ordered a cv from Jesse, why waste teim and money on anythign less... :wink1:
I went with the flange at the 205 as well,
Click to expand...


you go 1350? How much that run you with the driveshaft and flange if you dont mind me asking?
 
I added 7" if lift to my blazer, and with standard "u" joints, I found that I developed a vibration at around 50 m.p.h. This sucks, because I paid to have the driveline lengthened the first time, then because of the vibration issue, I paid a second time to add a c.v. head. IMHO if you have over 4" of lift, save yourself the headache and time and have a c.v. driveshaft built.
 
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