Nothing like introducing ROUND 2...

RALPH, LIKE I SAID...and Monte who's opinion about pinion should be agreed.

Slap the driveshaft in, check the angle against the diff yoke. Make sure you have at least 3 and go cat go. Bet it works better at 5

As for pinon having no effect in traction/hit with leafs or ladders, that's keyboard cowboy crap. It does help, and that's from actually adding pinion till it bites in SEVERAL cars, not watching engineering videos, and imagining what it must be like to go racing.

Like Monte said chassis cars are another deal entirely. I have an RJ car that only has 1.5 pinion, but the driveline is straight at the pinion. My ladder car has 6.

Thanks, THAT'S is what I was looking for.

Wait! Wait! I need a pig in the trunk? Does it have to be live? Can't I just go to Wallyworld and buy a couple of hams and put them in a cooler in the trunk? Or does it work better if they are hot? Should I cook them first? Can I make a sandwich when I get hungry? This pinion angle thing has me so confused. Oh heck i'm just going to measure it Monte's way and then measure it Drdiff's way and split the difference. But the darn ham sandwiches stay in the truck until I get hungry.

The manner in which you change the angle is what changes the traction, not the angle itself. When you adjust the angle on bar cars, you usually ALSO change wheelbase, ride height, chassis preload, etc. On leaf spring cars the shim changes ride height.

Picture what happens in a rear suspension. And mind you, I'm talking about making just minor pinion angle changes, and not correcting u-joints out of operating range. The driveshaft rotates the pinion, forcing the ring gear to rotate down, and the pinion tries to climb the ring gear and rotate the housing up. Changing the pinion angle does not add any additional rotating torque to the pinion - it only changes the place on the ring gear that the pinion applies it's force. It doesn't matter if the pinion is at the 8, 9, or 10 o'clock position - X amount of torque is going to try to rotate the ring gear X amount, and try to twist the axle X amount. PERIOD. It's no different than using a torque wrench - if you apply 100 ft/lbs of torque, does it matter if your handle is at the 3, 6, 9, or 12 o'clock position? OF COURSE NOT, so I don't understand why people claim it matters where the pinion is trying to rotate the ring gear from. Same amount of force - same E.T. I can't explain it any simpler, but I'm sure some people still won't get it. Still waiting for someone to show with some engineering logic that I'm wrong, but nobody from the last 10 times this was debated has stepped up.

This ain't my first rodeo - any chassis and engineering classes I completed were IN ADDITION TO, not instead of racing passes.

Wow, I can't believe this is still goin strong but understand why and it's quite halarious indeed. Here's one, vacuum secondary carbs suck.......PERIOD!

Not really - the higher atmospheric pressure actually forces air through the carb, not "vacuum" pulling it through as many blowhards contend (pun intended LOL). But I'm guessin' that wasn't what you were getting at.

Did you perhaps intend to post this in the "Old theories die hard" thread?

I'm kind of surprised that no one has posted any carnage stories with or without pics that might have been the result of using the wrong pinion angle method. Likewise nobody has reported any anecdotal evidence of E.T. or mph improvements after correcting their pinion angle. Is it possible that either method will get you close enough to not make a significant difference?

"If it is wrong but it works then it is not wrong"

What we really need is an "I'm so gifted that the laws of geometry, physics, hydraulics, etc. don't apply to MEEEEE" thread. Some of these people need to change the bong water before loading up another bowl . . .

Quicktree blew up rears constantly

Incorrect angle will usually cause a vibration before it becomes a breakage issue. The opinion of what is normal vibrations in a race car varies greatly.

As to the anecdotes - while there has been a few - I showed my hand with "mechanical logic" on why pinion angle doesn't effect traction. While I hear "anecdotes" that it can, NOBODY has ever come forward that can explain exactly how it works. I'll take mechanical logic over anecdotes any day - others can form their OPINIONS as they wish.

My point was the PERIOD in caps which closes off any other options or facts because I said so. As far as vacuum secondary carbs go, I don't know enuff about making them as good as a dp and don't think they are and converted two in the last month with way better results than the vc's.

"Because I said so" logic only worked for my Mom until I was about 12, so for the last 40+ years I have usually required some meat with my 'taters

Life's a game, choose your path and let er rip as far as I'm concerned.

Last observation on the subject..........seems the guys who BUILD or RACE cars and who have been doing it a long time, McAllister, Bob George, Darren Tedder, Al Alguire, myself.......seem to do it one way and the keyboard warriors and parts vendors do it another.........hmmm.....Oh yeah, lets not leave out David Wolfe, builds car for a living........he apparently is all wrong as well.

Evil, your wrong and Darren Tedder is right. Suspension angle changes aside, more pinion angle CAN make a leaf car hit the tire harder. You can crunch all the numbers you want and SHOW any amount of proof it can't help........but it does at the track and that is what matters. That's an "old school" trick that was used long ago when tracks and tires were junk, but it DID work.........wouldn't be needed today. Now, you want "engineering" logic as to why, sorry can't help you, even though I have mechanical engineering background myself, just know it works. But it is nothing new for the "numbers" not to make sense. How many millions of new things you think have been engineered that SHOULD have been better, but were not. Race cars in particular are full of things that SHOULD or should NOT work better or worse.........but what SHOULD happen at times don't always work out like that

Oh, and Jerry, YOU are wrong, how about YOU get over it


Monte

I'm going to pretend you didn't say that. I have nothing to do with your rear I dont swing that way musta been your boyfriend

Everyone is taking this far beyond the level of commonsence comprehension.Though there are many ways to set the angles it is generally agreed that if your working with a chassis that already has the drive train fixed and mounted then you can only deal within the limits of the adjustments that are the simplest to achieve.Since the engine and trans are located where the manufacture placed them and the only thing you change is the ride height and type of rear suspension you only need to keep the angles as near parallel as possible,both up and down and side to side and with in the working range of u-joints.The only adjustment you need concern yourself with is how much movement occurs under power and what angle you have to set at static to have the ideal aglinment under power.Since your not changing the fixed componants that leaves the observed static angle and amont of rotation and movement that occurs under power.We used GO-Pro cameras under some of of our cars to view this and found that there are many things that can determine the end setting.Most any or all correction can be made at the driveshaft and pinion u-joint and most all aftermarket suspensions give you that adjustibility.When building a chassis car it is much easier,once you set your engine and trans where you want it just point the pinion at the trans output shaft either upward or downward, then adjust the bars for the recommended final angle.Not everything has to be a constant debate,if you disagree that's fine,remember conversation between people should be an exchange of ideas and knowledge,an argument is an exchange of ignorance.Or the best is ones theory,ie: a theory a fact,opinion,pre-supposition or conjecture that can't be proven or disproven..

so what you are saying is this video doesn't mean a thing?
https://www.facebook.com/photo.php?v=470937339716400&fref=nf

and it's ok to have the ujoints turn at a different speed? and it's ok to put pressure on the output shaft>

That example is around 40 degrees. Not 1 or 2 a car might see. Just because whats his name Dave Morgan had sweet tea at your house does not make him right