The downside to 875 rwtq and lifting the tire in a limo sized lightning...

[harley#356]

Copy and paste from my thread on LR...so nothing new typed up here if you saw it on LR, but for those few left who don't go on LR, and aren't on FB, heres' my results from Saturday lol........




Well I never would have guessed in a million years that this was going to happen.....but I snapped my PST carbon fiber driveshaft like a twig! :shocked003

1st pass out yesterday, truck spun out of the hole, 1.7 sixty and a 10.5 pass....blah. 2nd pass out, she hooked like a mo-fo, on it's way to another 1.34 range sixty foot, and POW! My truck broke it's weiner :laughing25

Unfortunately the wall blocks the video when it actually snaps so I can't see which side fell first, but I'm thinking the rear snapped at the yoke first from being fatigued over the years, and once that threw out it caused the carbon tube to shear from being thrown so far out of alignment from the yoke breaking. Whatever it was, it happened FAST because the driveshaft was rolling behind the truck before I even passed the concrete barrier LOL. I bought this CF DS back in 2005, so I've had it 8 going on 9 years, about 8k street miles, about 100-150 1/4 mile passes, and about 50 dyno pulls. So not terribly used, but not brand new either. I haven't touched my suspension or pinion angle in 6 years either.


Here was my first launch...

2nd pass Carmelo was behind me, so of course he whipped out the phone to snap pics of my broke truck getting pushed off the track LOL

The carnage....:bolt

The great thing about a CF DS, is when it breaks, it shatters instead of really damaging much else. The extent of my collateral damage is 2 tiny little black marks on my muffler lol

The rear u-joint is still in tact

My $100 winch from harbor freight was the BEST investment I ever made for my trailer! lol

Carmelo steering while I winch it up

My trophy for the day! LOL. You know what, I think I just shortened it to the right length for a Lightning driveshaft, so maybe I can resell the bigger half to somebody with a Lightning :laughing25

Couldn't pass up getting a pic with JL during the awards with my carbon fiber trophy lol

Now for the videos! WARNING....not for the faint of heart :smt042

This video is my go-pro, you can see the front end come up, tire lifts off the ground for a split second but then gives out and DROPS right back down when the driveshaft snaps....OUCH. Then the sound at the very end, man oh man it sounded 100x's worse inside the cab let me tell you! lol

JLP Cecil Shootout 2014 - Harley#356 Broken Driveshaft - View 2 - YouTube



This is from the fence, my mom recorded this one. You can see the nose come up, then SNAP it drops right back down, and coasts out. Funny watching the vids after the fact, it felt like SOOOO much longer in the drivers seat, time really does move slower. I felt a killer launch, then just felt a loss of power, so I went to put it into neutral as I coasted to the right to get off the track, and then CRUNCH CRACKLE GRIND I heard that HORRENDOUS noise at the very end, it must have been when the front half of the DS finally dropped down to touch the ground and really make some nasty noise I thought my transmission just grenade till I hopped out and saw the guy carrying my driveshaft lol

https://www.youtube.com/watch?v=AZnHpNxVPqg&feature=youtu.be


Just wanted to say thanks to all the guys who helped push me off the track, and then who also helped push me uphill through the staging lanes so that ghetto tow truck didn't have to screw up something on my truck trying to throw that hook on the back to drag me out lol. And then for helping hold my truck on the hill since I've got no e-brake and park doesn't work without a driveshaft until I could get some wheel chocks over to it and bring my trailer over lol.

 

[rudder9]

That sucked to see Josh. It had just happened as I got there Sat. I was originally under the impression that was a brand new DS. After seeing that you've actually been running it for a good bit, makes it seem a little less harsh. Well get a new one and get her back up running. Love watching that big tank run.

 

[Jamie V]

That's why I go with the heavier 3-1/2" chromoly shaft with forged ends. That's a ton of money down the drain!

 

[prambo]

I had just left the fence and went over to sit in the stands with the kiddos when you ran that pass. My 5 yr old started saying "his cage came apart!" (So she was a little off-she's 5!). Glad to hear there was no other significant damage . I know I cringed at the thought of the other half flinging around under there.

 

[huffentuff95]

That sound, sounded familiar.... mine had a more metalic sound and the shaft kept catching on the front yoke making a bad clicking sound. Did the did your yoke fall out of the tranny??? So is another CF in order knowing you I say YES!!! I didn't realize you had it in for that many years

 

[harley#356]

That's why I go with the heavier 3-1/2" chromoly shaft with forged ends. That's a ton of money down the drain!

a steel shaft isn't going to be stronger in the middle, maybe the ends, but they do have upgraded ends now. Going to call tomorrow for full details, but this being an 8-9 year old DS, plenty of time for fatigue to have taken place, and when I bought it I was only at 400 rwhp so I wasn't concerned with needing any crazy driveshaft.

And if I had a steel shaft under there and if it broke, I guarantee there'd be as much collateral damage as the added cost of the CFDS that did no other collateral damage, so it's all works out the same roughly in the end.

That sound, sounded familiar.... mine had a more metalic sound and the shaft kept catching on the front yoke making a bad clicking sound. Did the did your yoke fall out of the tranny??? So is another CF in order knowing you I say YES!!! I didn't realize you had it in for that many years

Yoke stayed in, which was good since it didn't drip anything on the track, and Carmelo was able to still get out and rip off a 9.5 pass right behind me since I was in front of him lol.

Definitely ordering another CF DS, just with upgraded ends, and going to double check the pinion angle. I'm swinging by Joe's today after work, while I need to order a new DS anyway, I might put a 9" rear in it and shed ~100 lbs off the pig. No time like the present since that's something I've always wanted to do, and would require a new DS anyway.

 

[tpr103]

I had to check under my truck to make sure my cfds was still there lol.

 

[oilwell1415]

That's why I go with the heavier 3-1/2" chromoly shaft with forged ends. That's a ton of money down the drain!

^^^Not this.

And if I had a steel shaft under there and if it broke, I guarantee there'd be as much collateral damage as the added cost of the CFDS that did no other collateral damage, so it's all works out the same roughly in the end.

^^^This. And the CF shaft is safer.

 

[droppedf100]

What is the weight of your truck? I have a 3.5 chromoly shaft done by Rebuilt Parts in Pennsauken. It has been in my truck since 06 and I probably have 20,000 street miles and 1000 1/4 passes and maybe 15 dyno pulls. I'm around 4100lbs race/ street trim and truck is a std cab shortbed which helps I'm sure.

 

[Jamie V]

You guys keep buying your CF shafts, I'll go with my CM one.

 

[Copperhead]

You guys keep buying your CF shafts, I'll go with my CM one.

Yep,....

I agree with you Jamie.

 

[harley#356]

What is the weight of your truck? I have a 3.5 chromoly shaft done by Rebuilt Parts in Pennsauken. It has been in my truck since 06 and I probably have 20,000 street miles and 1000 1/4 passes and maybe 15 dyno pulls. I'm around 4100lbs race/ street trim and truck is a std cab shortbed which helps I'm sure.

Full street trim, with me in it, over 5k lbs. Full race trim....top secret lol

My truck is a 139" wheelbase, the driveshaft is almost 70" from u-joint centerline to u-joint centerline, so it's a looooooong azz driveshaft which doesn't help the matters lol

You guys keep buying your CF shafts, I'll go with my CM one.

You say that like they break all the time lol. In all the years on the boards I've only heard of 2 failures. Jody's breaking the glue joint (which weren't they able to reglue?) and mine which I think is primiarly due to fatigue from a not ideal pinion angle over the years. I'm actually surprised that as performance and weight oriented as you are as priority #1, instead of budget and frugal oriented as priority #1, that you don't have one. It's a significant chunk of weight loss over a steel one, rotational mass at that, and the tube itself is 3 times as strong as a steel one, and if it does fail, it's waaaaay safer with less shock with less inertial mass flying around, won't do collateral damage, won't pole vault, it just shatters harmlessly. The added cost? ~$500-700 more in most cases, which is a drop in the bucket compared to other areas on the truck, for something that also adds performance, sheds weight, and has added safety, win/win/win.


PST emailed me back and said they think the U-joint or the 7075 yoke failed first. And with my increased hp he recommended i go to a 0.180 carbon tube, and that they have made improvements to the tube yoke since I bought mine nearly 9 years ago. And he also recommended going to a spicer joint (not sure what was in there). Once I come to a decision on the rear end, I'll order up another one. In the mean time, I picked up a stock aluminum driveshaft for $100 from a 4R70W truck. Going to get it cut down to fit my 4R100 truck to get me up temporarily, and check out my trans to make sure nothing internal got hurt on the shock of the snap from full load to no load when it broke.

 

[droppedf100]

Full street trim, with me in it, over 5k lbs. Full race trim....top secret lol

My truck is a 139" wheelbase, the driveshaft is almost 70" from u-joint centerline to u-joint centerline, so it's a looooooong azz driveshaft which doesn't help the matters lol

Lol top secret. My weight is exactly the same race or street. I always drive my truck to and from the track which is another reason I like chromoly as I can't push it into a trailer if it does go. I believe my ds is 52". Only thing have trouble with is the trans yoke twisting

 

[Jamie V]

I'm sure that CF one is way lighter then the CM one. But my biggest problem is those ends that are aluminum. If that thing had forged steel ends in it that would be a different story but it don't. But I think you hit the nail on the head with your problem being the length of it.

When you say it's $500-$700 more that is double the cost of a CM strange one that I had that in my race truck that was launching at 5500 rpms off the trans brake.

This truck I'm building is going to be an all around truck. I'm not pulling seats to go racing, I'm not putting skinny wheels up front, I'm not changing anything to go racing. I care wayyy less about weight then I ever did before.

 

[harley#356]

Lol top secret. My weight is exactly the same race or street. I always drive my truck to and from the track which is another reason I like chromoly as I can't push it into a trailer if it does go. I believe my ds is 52". Only thing have trouble with is the trans yoke twisting

What's streetability have to do with cf vs steel? It's 3 times the torsional strength of a steel one. The 2013+ GT500's come with a CFDS from the factory. Heck ShadyAl probably has at least 50,000 if not closer to 60-70,000 on his CFDS in his supercrew HD.

I'm sure that CF one is way lighter then the CM one. But my biggest problem is those ends that are aluminum. If that thing had forged steel ends in it that would be a different story but it don't. But I think you hit the nail on the head with your problem being the length of it.

When you say it's $500-$700 more that is double the cost of a CM strange one that I had that in my race truck that was launching at 5500 rpms off the trans brake.

This truck I'm building is going to be an all around truck. I'm not pulling seats to go racing, I'm not putting skinny wheels up front, I'm not changing anything to go racing. I care wayyy less about weight then I ever did before.

and the ends being aluminum have not been a problem, they run those exact same ones in 3000 hp pro mods. My case is a pretty isolated incident. I actually took the u-joint off the pinion tonight, it's pretty much a smoking gun. The u-joint failed before the aluminum ear broke. When I took a pic underneath before, the good side was showing, not the bad side, so I never noticed it. I'll try to post a pic tomorrow. The one "nub" or "ear" or whatever you want to call it, one of the 4 nubs that rides in the bearings, was half eaten away. There's no way the damage was from the instantaneous driveshaft snapping, it was a long time in the making from the metal eroding, eating away at the needle bearings over time, causing a ton of slop/bind/whatever, which caused it to finally fail on that launch. A non-ideal pinion angle is likely the cause of that u-joint premature wear over the past 9 years. Not bad enough to cause a vibration, but bad enough to eat away over time. So whether it was a forged steel end, or an aluminum end, it was the steel u-joint that triggered it all, so that driveshaft was destined to fail regardless of the tube and yoke material, and that extra $500-$700 it cost me, easily saved me $500-$700 in other collateral damages from the CF tube just shattering harmlessly after the u-joint broke vs. having the u-joint break and the steel shaft whailing against everything under the truck unrelentlessly.

And come on now, care way less about weight than you ever did before, but you're running feather-light bogarts on the street that are probably the most notorious wheel out there for bending under street use despite repeated claims they came up with a "street duty" wheel this time around? lol There's plenty of other slightly heavier, much cheaper, much stronger options out there. Your rationale for driveshafts is conflicting with your rationale for wheels! haha

 

[oilwell1415]

Even if they are $500-700 more, people spend a lot more on other items that don't return any better on their investment.

 

[Jamie V]

See you live in a world where there are tons of wheel options for 5 on 135mm bolt patterns. We have like 2 options. I wanted 15x10's out back with 17x8's up front. There aren't many options at all. I asked Rich to make my wheels as thick as possible to try and prevent breaking.

I don't know how someone sells a $1500 driveshaft with crap u-joints? I just can't justify that much money for a fuse able link. That's like the guys who use to tell me they didn't want cometic head gaskets because they would rather blow a head gasket then melt a piston.... Just tune it right if your going to melt a piston.

I'm glad your shaft didn't hurt the truck and for guys like you who try so hard to loose every pound that is a great place to shed some good weight. But when you don't care that much I'd rather spend that $600 upgrading my blower to gain 125hp.

 

[droppedf100]

I wasn't referring to streetable as much as reliable. But your right it could be a fluke thing your shaft broke. And Jamie is right try finding any wheels for 5x5.5 pattern. I had to convert my 79 to 5x4.5 in order to have drag wheels.

 

[harley#356]

See you live in a world where there are tons of wheel options for 5 on 135mm bolt patterns. We have like 2 options. I wanted 15x10's out back with 17x8's up front. There aren't many options at all. I asked Rich to make my wheels as thick as possible to try and prevent breaking.

Ah see us Gen 2/HD guys and you Gen 1 guys, we aren't so different afterall lol.....we only have 2 options for 15's as well....bogarts and racestars, which race stars only came out this past year. While yes there are other 5x135 options for other sizes, 99.999% of them are fugly/ghetto/donk/not-drag-truck-style so it's moot on those.

I don't know how someone sells a $1500 driveshaft with crap u-joints? I just can't justify that much money for a fuse able link. That's like the guys who use to tell me they didn't want cometic head gaskets because they would rather blow a head gasket then melt a piston.... Just tune it right if your going to melt a piston

Damn every time you reply my driveshaft costs more and more! It started as $900, then $1200, now $1500, next reply will it be $1800?! lol

Before any information about PST gets skewed, because you are skewing it Jamie, it was NOT a $1500 driveshaft, it was $900-$950 when I bought it. Iit did NOT come with crap u-joints, and it did NOT fail right after I installed it, and the driveshaft material is at NO fault of my failure after taking the rear yoke off the pinion last night, the u-joint was. And why did the u-joint fail? I would not say it was crap material, I'd say it's due to my pinion angle very likely being not properly set. Put the best u-joints in the world on an improperly setup pinion angle and it will wear it prematurely. I have no problem admitting that when it all boils down, the blame falls on myself for installation error never dialing in my pinoin angle. I'm not going to blame a part to save pride. It is NOT more likely to break than a steel or aluminum shaft, it's actually LESS likely...BUT if you DO have a u-joint failure, which again, irregardless of what driveshaft material you have in there, if a u-joint is going to fail, it's going to fail, and the CF will do the least damage when that failed u-joint ejects the driveshaft. In addition to providing the safety, it saves weight, and increases performace from less rotational losses. There's 1 drawback to the CF, the price, other than that, it's safer, stronger, and lighter. You can't call a CFDS a fusable link without calling a steel or aluminum that too when they're both weaker than CF.

Just like your analogy of saying just tune it right and you won't melt a piston if you run XYZ head gasket, well same scenario here, just set the pinion angle right, and you won't prematurely wear a u-joint to the point of a failure!

In all of this don't forget the fact that I bought this DS just shy of a decade ago, ~9k miles, ~150 passes, ~50 dyno pulls, and lots of flogging and abuse later, my truck at that time only made 412 rwhp, and PST custom builds each driveshaft to spec, they inquire on your hp level, expected E/T, etc. when they get your length measurements, and at the time I had ZERO expectations my truck would ever be making over DOUBLE the power it is 9 years later, especially since at that point in time I had just DOUBLED my hp from the factory ~200 rwhp to the then ~400 rwhp, so I ordered my driveshaft for a 400 rwhp, mid 12 second, truck. Now clearly PST builds it with a factor of safety involved there, because even DOUBLING the power for what my DS was ordered to, it still held up. Maybe the u-joints were the STRONGEST on the market, but they were plenty strong for 400 rwhp, and 500, and 600, and 700, and into the 800's for a short while, and if my pinoin angle was right, who knows how long they would have lasted. It wasn't the hp that killed it as much as the miles and use they saw under bind from an improper angle.

And back to my pinion angle, additionally my truck used to be SLAMMED, back in '05 when I ordered the driveshaft, I had a 3/5 drop, no pinoin shims. I KNEW my pinion angle was wrong then, but there were no vibrations so I didn't worry about it, and my truck came stock with no shims at all, so I didn't have any shims to flip it and set it right. But hey in '05 I was a college freshman, the CFDS sucked up all my cheesesteak and beer money, I didn't want to spend another $10 for shims....that's 2 philly cheeseteaks and a case of Miller Lite lol. Around '09 I finally lifted the rear back up to ~3" drop when I got serious about drag racing, the pinion angle got better, I figured if there was no vibration before, there's less chance now, why bother with dialing it in exactly if it works. I've had that exact rear suspension combo ever since. Bought an angle finder a few years back to measure my pinion angle in the quest to help dial in my 60's, figuring a positive angle wasn't helping my 60's, then after tweaking shock settings and shedding weight and adding a cage my 60's dropped into the 1.4's, and then the mid 1.3's. At that point, I didn't want to touch ANYTHING, because my truck was HOOKING! Well....now it bit me. So I'm still not going to blame it on PST, or the driveshaft material, or the aluminum end yoke, or even the u-joint that triggered the cascading failure, it actually comes back right to me. So flame on against how could I be so dumb to not set my pinion, it's well documented that it prematurely wears u-joints if it's incorrect, but don't go spreading rumors that my driveshaft cost 50% more than what it actually did, or that it failed because it was cf, or that the u-joints were junk, bcause absolutely none of that is true.

Also after talking with PST, sending them pics and videos, they did concur with me that it wasn't the CF that broke, the rear yoke broke before the DS, and that they have made improvements over the years to the design since I bought mine, and that they would use a thicker wall and different yokes and joints this time around since my truck is making double the power for what the old one was spec'ed to, especially since the excessive length of mine puts a lot more stress on the components than a shorter one.

II'm glad your shaft didn't hurt the truck and for guys like you who try so hard to loose every pound that is a great place to shed some good weight. But when you don't care that much I'd rather spend that $600 upgrading my blower to gain 125hp.

Well if I could spend $600 to upgrade my blower to gain 125 hp I'd be all over that mod too. But I'm well beyond that point, any improvement I want to make now costs at minimum of thousands, and when my truck is nearly tapped out in every area for potential gains shy of spending several thousand dollars at a time, spending an extra $500-$700 for keeping an ultra light weight, stronger, safer driveshaft in it, is a no brainer for me. A CFDS is already in my truck's baseline, so at this point I'm not going to cheap out to save a whopping 500 bucks to go slower, and have a piece in my truck that if it failed again would do even more damage, just because I wanted to save a few bucks. I've been modding this thing long enough to know that logic doesn't work anymore lol, money is going into the truck no matter what! haha

I wasn't referring to streetable as much as reliable. But your right it could be a fluke thing your shaft broke. And Jamie is right try finding any wheels for 5x5.5 pattern. I had to convert my 79 to 5x4.5 in order to have drag wheels.

I would say a CFDS is every bit as reliable, if not moreso, than a steel or aluminum one. Especially because I've seen and heard of countless driveshafts fail over the years, and I've only ever heard of 2 being CF, and one was Jody's wheelie machine that broke the glue joint, and the other being mine which root cause is coming down to the u-joint wearing excessively over time from a bad pinion angle, which would have killed any material driveshaft that day.

 

[Jamie V]

You said they were $500-$700 more. A good CM shaft will cost you $600-$800 (with CM yoke and solid joints) so I jut added $500-$700 to that.

If that CF shaft had steel ends in it instead of AL it probably wouldn't have came apart like it did. Do the new ones have AL ends still?