Carrier bearing or 1-piece driveshaft?

[zombie]

Because I don't see how balancing a lighter 1 piece shaft can be harder than balancing a heavier two-piece shaft? Can anyone explain? How is one "more" or "better" balanced than the other? Is this "common " balance problem related most to improper manufacturing, shipping damage, or improper installation?

it's not about the weight, it's about the length of the shafts, 2 pc is much shorter (because they are balanced individually, not as a single unit) hence easier to balance

the balancing is all about making sure the critical speed of the shaft is above/outside the operating speeds the shaft will see

 

[Nick M]

1 piece is a good option because of price... You get a brand new shaft as well as new joints for a little over $300, whereas with stock you are almost at that price point just replacing the center support bearing, then you have to hope your rear bonded section has not shifted, that your u joints are good, and that the shaft is in balance. So depending on the previous condition of the stock shaft you could be paying well over the price of a 1 piece. As far as comfort is concerned, most of that goes out the window when you start modifying it, I can almost bet driving a lightly modified supra with a one piece is not going to have a sensible difference than one with a two piece, at least not a big enough difference for the majority of us to give a hoot.

This is a Supra, not an old Fox Body Mustang.

 

[CyFi6]

This is a Supra, not an old Fox Body Mustang.

Whats your point? If you are trying to argue that what I said is invalid because you must spend more money on everything simply because it is a Supra, I am not really interested in arguing, but if you have an actual point I would love to hear it. There are good points about the pros/cons of both options in this thread. The reason I purchased a one piece shaft instead of repairing my old stock shaft is because of everything I stated in my previous post. I don't have a doubt that a perfect condition stock shaft and support bearing is better than a one piece in most cases, but for my needs the one piece will suite me just fine, as it would many others.

 

[tsupranami]

it's not about the weight, it's about the length of the shafts, 2 pc is much shorter (because they are balanced individually, not as a single unit) hence easier to balance

This is true: it's increased length is the weak link in the one piece balance equation. The lower mass can compensate somewhat if the shaft is properly built and balanced however. And balanaced is balanced. It either is or isn't, regardless of length.

the balancing is all about making sure the critical speed of the shaft is above/outside the operating speeds the shaft will see

Exactly. Sucess in anything depends on quality of construction and proper installation, operation, and maintenance. If it's imbalanced, then it is a manufacturing defect, damage, or procedural defect from the balance operation, not a weakness of any one design or material.

Most of my "catastrophic failures" of any systems, drivelines and otherwise, dirtbikes, aircraft, boats, rc vehicles, electronics, etc, have been due to improper manufacturing, installation errors, or the operator (ooops...) pushing the device beyond it's design/wear limits.

51,000 Toyota Tundras were just recalled because of driveshaft manufacturing defects. http://www.atlantainjuryattorneysblog.com/2011/04/truck-safety-alert-51000-tundr.html

So even if your careful with what and where you buy your parts from, or who installs them, sh*t just happens sometimes that is beyond our control! (Ford Pinto, Firstone Tires, Supra BHG, need I say more?)

But I still trust Toyota parts more than any others that I can think of....

Still, in the interest of experimentation, I am testing the 1pc in my car. I trust it's design and build quality enough to run it just as hard, (ok maybe a little harder) than the stocker. I'll be here telling everyone about it if it fails, especially catastrophically.

I'm keeping the stocker in the wifes for ongoing comparisons, since she's easy on it and it still feels and tests out great,even at 211,000 on the ODO.

It's been several years and 20,000+ miles so far, and the 1pc has exceeded my epectations, although I am now going to install a hoop, 'cause this thread got me thinking....:icon_ques

It also got me wondering, how many folks have sucessfully rebuilt the stocker, how much did it cost, and how long has it lasted, dollar per mile kinda stuff, ya know?

 

[tsupranami]

Funny, most of the high end cars and race cars you mentioned use torque tubes, which is an entirely different animal... Heavy trucks run multi piece driveshafts, so your point about power has zero merit..

C'mon, trucks don't use puny Supra driveshaffts...they use massive ones designed for the power being applied....silly rabbit...:nono:

Again, huge loads transmitted at low shaft speeds. But then again, if you drive your Supra like a truck, I guess....LOL

The stocker was designed to acheive comfort at the expense of performance, it was built to a budget (ie. not a torque turbe $$$$), and is more than adequate for a certain range of power over time.

Start working one or the other (age and time or excess stress from incresed power) or both, and you have a system that will need more maintenance or could fail more easily. At my power levels and driving habits and a brutal RPS MAX/Ferramic clutch combo, I was killing suppport bearings on a semi-annual basis. Dollar per mile, plus time lost repairing, it just wasn't adding up well. Ergo, I'm tryin out the 1pcr for a while...

I wish I could find the thread on here where the guy had a catastophic failure at speed. He's very lucky he didn't wreck, and it tore a nice hole in the bottom of his car and severed all the lines under the car.

I'm sure I've seen it before, I think I remember it. I know it happens. I saw it happen 25 years ago when I was in high school while following (racing??!?) my freinds 68 Chevelle. It happens. A boy was killed last year in the Tacoma Dome near here because a monster truck had a driveshaft failure that sent an improperly welded driveline hoop sailing into the stands.

But one failure (nor 3 in 25 yrs) does not make an epidemic; it is however, a tragedy, nonetheless.

AFAIK, there are few, if any 2 piecers used by preference in any forms of motorsports or racing. If so, I'd like to know, just for giggles and grins if nothing else...:icon_surp

But I do know for sure the high speed driveshaft market is dominated by high quality 1 piecers when budgets are a factor. Most deisel truck racers ditch their 2pcr's when they boost the power and take it to the track..

I also know that anyone can head to a Nascar, GrandAm, or NHRA/IHRA racetrack near them for living proof of high speed one-piece driveshafts routinely and safely going over 200 m.p.h. Now if they could just keep the wheels from flying off as well as they can contain errant driveshafts...:yikes:

---------- Post added at 04:24 AM ---------- Previous post was at 04:19 AM ----------

BTW, Poodles, I think ur car is sexy! Luv the red, we had one a few years ago that was almost that nice...seeing yours again makes me wish we woulda kept it....go7M!

 

[IJ.]

"Critical speed"....

Using the 2 piece has FA to do with shaft weight.

Low Diff gears High top speeds and high engine RPM can easily put a shaft outside of it's critical speed limit and it will fail.

I crunched the numbers for my car looked at my driving style and decided the expense of a well built 2 piece far outweighed a failure at high speed shortly followed by my death.

 

[Poodles]

NASCAR doesn't run 3.73:1 rear end ratios either. Vehicle speed =/= drivetrain speed. Not to mention harmonics take time to cause the failure, so drag strip isn't a good judgement either. Doing top end runs through the desert is very different from drag strip. Not to mention many cars run shorter driveshafts, etc.

The stocker is very strong, it's weakest link is the bonded rear section, and if that gets out a phase would cause you to eat carrier bearings (sound familiar?). There is no other excuse for eating carrier bearings because they simply support and isolate the driveshaft.

All the top supercars in the world these days either run torque tubes to rear mounted transaxles or they're mid engined. The ones that are mid engined and AWD have driveshafts that are extremely short.

 

[tsupranami]

Wow IJ, that shaft is massive!

I bet all the girls say that though...lmfao!

So I guess you felt that the stocker was inadequate for your intended purpose.

Just guessing, but that probably didn't come cheap...$$$

I beleive that is what I've been saying this entire time; if it is properly designed and built, and the calculations for critical shaft speeds, tube thickness, shaft length, etc. have been accounted for, then it should be as safe as any other driveshaft of similar quality. regardless of design style or materials.

And shaft failure at high speeds, 1pc, 2pc, or more, is still a dangerous scenario. That massive chunk of steel slapping around in the tunnel and trying to pole-vault the car over the dangling shaft can spell disaster no matter what the shaft is made of or how it is supported. See the aforementioned article regarding Toyota Tundra driveshaft recall.

That is why all high-speed or extreme-power applications require or at least recomend installation of a driveshaft loop, a time-tested and regularly proven way to prevent a catastrophic driveline failure from becoming a catastrophic wreck.

So again, what is the car intended to do? High speed runs at high power levels: one should start looking into safety as much as performance.

Grocery getting at stock power levels? Stock shaft is more thatn adequate for that.

Doing high-speed tractor pulls with your Supra (and have a big$ budget$)? Get one built like IJ's...LOL!

 

[tsupranami]

A blown tire, failed brakes, or other far more common mechanical failures are what worry me most when I'm on the edge.

For me, I trust the odds. I am certain that I have a better chance of being struck by lightning three times and surviving (or winning lotto) than I do of having a catastrophic driviline failure simply because it's a one piece aluminum shaft.

Funny thing is, pretty soon, driveshafts will be a thing of the past. Everyone is now moving to direct-drive electric motors and transaxles. Soon, saying your car has a driveshaft will be like saying you are going to adjust your points?!?

 

[digihonk82]

Didn't you guys catch that episode of Mythbusters? Pole-vaulting a car, via driveshaft failure, was myth-busted:nono:And for the sake of this thread, I employ a steel 1 piece "driveshaft shop" DS. I have no opinion except- one-piece=good, two piece=me likey not soo much:icon_razz

 

[Enraged]

have you ever seen what a 1 piece without a driveshaft loop can do? say goodbye to your feet.

 

[Poodles]

Depends entirely on where it fails. A wear failure is usually at the u-joint. A power or harmonic failure is usually in the middle.

Also, it doesn't matter how high quality it is, the 1 piece is always going to have a lower critical speed.

 

[Enraged]

true, i just hope that anyone that does a 1 piece also pays a few bucks and gets a hoop.

 

[3p141592654]

http://www.supramania.com/forums/sh...ou-expect-less&p=719571&viewfull=1#post719571

 

[OneJArpus]

http://www.supramania.com/forums/sh...ou-expect-less&p=719571&viewfull=1#post719571

damn critical speed of 80mph lame...

 

[Poodles]

http://www.supramania.com/forums/sh...ou-expect-less&p=719571&viewfull=1#post719571

THANK YOU! I searched and searched and couldn't find it.

 

[hvyman]

Was that alum or steel?

A steel 1 piece properly built and balenced should hold up fine. I run one but id only trust 1 person to make them and he uses all new parts.. That person also has over 400 and drags his car a lot with slicks in the 11's.

Sacrificing quiality for weight is retarded and thats prolly what happened. OR they used used tubes. Something other than just being a 1pc caused that. Doesnt duane use a 1pc? IIrc he had a cf one take a shit when a rock prolly destroyed it.

The length of our stock driveshaft is well below the limit for needing a 2 piece. Its just more of nvh and driveability concerns as far as making a car to use a 2pc.

Edit: a lot of people complain about vibrating issues when they install a 1pc. If that is making it vibrating your shaft is not balenced properly. Mine actually vibrated less with the 1pc.

 

[Nick M]

Whats your point? If you are trying to argue that what I said is invalid because you must spend more money on everything simply because it is a Supra, I am not really interested in arguing, but if you have an actual point I would love to hear it.

So then you don't know the size of a fairmont platform. I didn't realize it. The Fox Body weighs in less than 3200 lbs with a cast iron block and heads. It is a small car with a short wheel base.

---------- Post added at 10:47 PM ---------- Previous post was at 10:44 PM ----------

Didn't you guys catch that episode of Mythbusters? Pole-vaulting a car, via driveshaft failure, was myth-busted

Have you seen them fail at their other automotive shows? Like having no idea what fuel trim is, then calculating which truck has better milage after driving in traffic. And thinking the Knight Rider stunt wouldn't work? They are special effects riggers. They don't know anything about anything. Well, the one guy is an engineer. I think. On the second team.

 

[zombie]

Didn't you guys catch that episode of Mythbusters? Pole-vaulting a car, via driveshaft failure, was myth-busted:nono:And for the sake of this thread, I employ a steel 1 piece "driveshaft shop" DS. I have no opinion except- one-piece=good, two piece=me likey not soo much:icon_razz

because mythbusters always use totally valid and correct math and science

 

[tsupranami]

Depends entirely on where it fails. A wear failure is usually at the u-joint. A power or harmonic failure is usually in the middle.

Also, it doesn't matter how high quality it is, the 1 piece is always going to have a lower critical speed.

http://www.supramania.com/forums/showthread.php?58272-Driveshaft-Critical-Speed-A-Calculator/page2

Use the wrong materials or the wrong diameter or thickness, and a 2 piece can be far worse...

Is anyone suggesting that the DS shops are knowingly selling parts that are designed and/or built improperly? If anyone has evidence of this, they should come forward as this would be a serious legal and safety issue that should be addressed ASAP.

And the thread on the 140mph Cressida/Chaser? 80mph critical speed? Seriously?

They would have had to been using playdoh...there is no mathematically possible way otherwise? Look at the photos again. And follow the thread. No updates, no word.

There are far too many variables in this equation to base an entire opinion on one isolated incident in a completely different type of vehicle.

Besides, I own a Supra, not a Cressida, nor a semi. My car was actually factory designed to go 150+mph. None of the other vehicles you've compared here are. That's why I keep comparing to vehicles designed to do that or more.