Why would you buy heavy duty half-shafts?

[SteveBCloud9]

O.k. Here's my thinking on the subject. Dodge designed the half shafts on the viper to be the part that breaks if any part of the powertrain would "give way" due to continueous hard driving (I was told). So why would someone buy heavy duty half shafts so that they don't break? I would think you would want to risk a $400 part (one half-shaft) for a $5,500 part (tranny), bent driveshaft, motor issue, etc, etc. Am I missing something here......

 

[Mike Brunton]

Stock halfshafts can be broken on street tires (ask Mike Pavloff!), and therein lies the problem.

When a halfshaft goes, it is liable to take some other stuff along with it. In Mike's case, I think it was his diff. housing (not good). You can get lucky and have the shaft shear near the diff. housing, but that's not always gonna happen.

The driveline (diff, tranny, motor) is MORE than strong enough to hold up to the largest amounts of stress that street tires can provide, and is probably Ok for even most slicks (MT's, etc). The tires are gonna spin before you blow a tranny or kill a rear end - but you don't want to worry about your halfshafts blowing on you before the tires even spin.

That's the reason most folks upgrade. I would say the next weakest link in the driveline is probably the clutch, with the transmission a distant third.

 

[GaryA]

I agree with Mike. I've broken TWO heavy duty half shafts on street tires in the past year (yep! you read it right HEAVY DUTY). The first one was at the track and the second one was doing an evasive maneuver on the street to avoid getting hit by a senior citizen making an illegal left turn from the far right lane. Fortunately I had enough momentum from the sudden acceleration to get past the impending doom, but I busted the half shaft which in turn took a chunk out of my differential.

There was a post here on the board a few weeks ago where somebody likened the half shafts to fuses in an electrical circuit. The only problem is that the stock ones are not rated high enough for the kind of abuse they might be subjected to(like putting a 1 amp fuse in a 2 amp circuit). I would much rather replace a half shaft than a tranny, but I think there is some leeway for heavier duty half shafts. I also installed half shaft loops this time to avoid the damage that can be caused by a broken half shaft. Luckily, both of my incidents were at fairly low speeds.

 

[MES]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>I've broken TWO heavy duty half shafts on street tires in the past year<HR></BLOCKQUOTE>


What part of your half shafts broke? The U-joints or did they just twist up? What kind of power are you putting down to break two? Also who's half-shafts were they? If you don't want to post publicly please e-mail me I'd like to know. Thanks.

 

[GaryA]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by MES:



What part of your half shafts broke? The U-joints or did they just twist up? What kind of power are you putting down to break two? Also who's half-shafts were they? If you don't want to post publicly please e-mail me I'd like to know. Thanks.

<HR></BLOCKQUOTE>


MES:

In both cases the U-joint broke. The first one at the wheel and the second one at the differential. My last dyno was 500 rwhp. They were BTR halfshafts. I've since upgraded to Unitrax halfshafts and they look much beefier.

 

[99 R/T 10]

How would you know if you slightly(partially) twist the half shafts? Are there any obvious indications?

 

[99 R/T 10]

By the way, I am still looking for some HD short shafts at a decent price. If anybody has any leads, let me know. Thanks,

 

[varanus]

Just curious as far as those who had damage from broken shafts, did you have safety loops on. If not do you think they would have prevented damage to the diff housing?

 

[GaryA]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by varanus:
Just curious as far as those who had damage from broken shafts, did you have safety loops on. If not do you think they would have prevented damage to the diff housing?

<HR></BLOCKQUOTE>

When my first half shaft broke I had no damage (because it broke at the wheel side u-joint and I pushed the clutch in immediately). On my second incident the differential housing suffered minor damage (this one broke at the differential side u-joint). Luckily I was going fairly slow when it broke. I hate to think what it would have been like at 100 MPH or so.

I didn't have the safety loops in either of these incidents and I believe they would have prevented the damage. Since then, I had the Unitrax half shafts and safety loops installed. I feel much better about this arrangement.

 

[Bad02ViperGTS]

Who sells the unitrax half shafts and loops.......

 

[King GTS]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Bad97ViperGTS:
Who sells the unitrax half shafts and loops.......

<HR></BLOCKQUOTE>


Apex Motorsports

 

[Bad02ViperGTS]

Thanks......King GTS.........

 

[MW]

<FONT COLOR="Blue">What u-joints do the Unitrax come with?</FONT c>
Might it be adequate to upgrade the stock Spicers (if a better one is availale?) if that is what breaks most of the time?

(stock shafts-2500rpm leave-1.8 0-60, BFG drag rads at 30psi-no problems)

 

[MW]

<FONT COLOR="Navy">Are the Unitrax safety loops a special fit for the Unitrax larger diameter shafts? How do they compare to a "universal" safety loop kit like from Summit? They must be a very unique fit/mount...thanks..anyone got a pic to share?</FONT c>