Just something i was wondering.

On the Top speed thread (which was apparently deleted again due to legal reasons) Someone posted a pic of his driveshaft hitting the bottom of the truck. I'm curious to know, was it the front shaft or rear shaft?
I'd imagine the rear one is most likely to break.

I never feel a shimmy but if i did i'd want to know which shaft to look at.

 

Vibration started at 115 until about 125 then stopped after that and ran smooth up to 145 until I shut down.

 

Yea i seen that already but is that the rear shaft?

 

Yes. Fronts are too short to really worry much about. Vibration is a function of speed, length, and material. The longer the DS, the lower the speed at which it will start to do that. Think about it like a wave. Shorter waves have higher frequencies. I think.

 

I realize that but i wanted to make sure its the back doing it. I don't plan on needing to buy one yet but i'd like to know ahead of time what to look for. so everyone's still running the factory front?

 

the above pic of "spoolin's" truck is a crewcab so he only has 1 driveshaft, but the ext.cabs have two, this is one thing that I am trying to prevent, so bought some driveshaft loops for both!!! just in case, but yes most of the time the rear one is the one that goes... but I would be more scared of the front one letting loose...imo

 

Oh makes more sense now. I thought he was asking about front vs rear like a 4wd setup. I forgot about the 2 pc shafts.

 

btw the second 'top speed thread' is still active. https://www.performancetrucks.net/fo...d.php?t=403434

 

I was confused too which is why I wasn't saying anything. Like AP said I had a one piece aluminum drive shaft that was...82 inches long? (I might be wrong about the length but it's in that ballpark). The length (and width) of that DS is what caused it to hit, oh and the speed at which it was turning. I've since switched to a two piece which given that it's a CC wasn't easy.

 

So the ECSB tend to fail often then? How come the shorter one breaks vs the longer one?
Also arn't all the ecsb shafts steel rather than aluminum?