rear end pinion angle?

[igotaneed4speed]

Lol
That was my return neg rep to him

Glad you have nothing to add to this but smart ass comments and the pointing out of my grammar/spelling mistakes. You still seem to be under the impression you're correct and I'm wrong and have yet to anything to prove the differ.

Well I won't name call, and my first reply was to a pretty vague post by you. I showed up to check on the the thread last night, and this was 4 days after you called me an idiot, not only after you called me an idiot. The reason I didn't add anything else is only because I am quite busy with family and work right now. It takes a little more time to post a well thought out answer and explanation compared to a copy and paste link fest.

Give me the rest of today and I will try to put together a well thought out answer.

I did type out a few an even gave a example which was met with more smart ass comments in return, no one attempted to explain themselves what so ever. When someone does not give the respect to give some sort of effort in a response why would I waste my effort typing anything out further than I did. If any of you three would have responded with "I disagree and here is why...." Instead of " lol, are you sure about that" I would be a little more cordial in my responses.

I look forward to you actually posting something useful and informative and being able to converse about it like adults without the sly comments.

[1BADAIR]

I did respond. How many people are gonna cut their brackets off the axle and reweld them to adjust pinion angle without affecting ic?

[oharaautomotive]

I think what Igotaneed is stating for his supporting info is correct but it is a balancing act Instant center, anti squat and pinion angle can be adjusted to help set up a suspension. it all depends on power and what type of suspension. For instance on a stock suspension Mustang there are soo many people out there making parts for them but what do they do? they take the flex out off the suspension and allow adjust-ability for these three things. Every type of suspension has it limitations but Just like what Bickel states once you do have the correct type of parts to control flex in the suspension you need to set the pinion angle accordingly to that set up, From my experience you don't want the pinion going past 0 and positive. Is pinion angle important yes but it is for tuning just like the rest of the suspension. Like i said its all a balancing act and every car is different. Needles to say if you have a stock suspension mustang Dave Zimmerman is your man the proof is in the pudding. If you have a leafspring car i would get on the phone with Calvert racing or SRD asassin bars, there are guys running there parts and flying.

Also want to state you have to look at the whole suspension of the car the front plays a big role there too. For instance Calvert will most likely want to know how much travel you are getting out of the front suspension and if the vehicle is lowered or will be lowered. And lowering a car 1" affects the center of gravity which will intern affect the Instant center and antisquat.

And just like what was stated earlier bolt everything in the car but snug it down so you can adjust things, and the suspension needs to be in the weighted condition, once you have it in place where you want it tack it in then remove and get to welding.

[Lunger]

I have done numerous changes in leaf spring cars. If the perch's are not welded, you set the perches on the springs set the rear axle on them , snug it up with the ubolts , put tires on it lower it to the ground and measure your angles. scribe lines, jack the car up loosen ubolt adjust and redo. Its a pain in the ass and takes forever. I like to set it at -5 degree , now this is on a old mopar with nothing but a pinion snubber. You can take two of the same model cars and they will both act different. Then you ask , what if you need more or less angle, after its welded and you are tuning it, you shove wedges inbetween the spring and the perch.




just pulled up an old car craft article.

How well the rear suspension controls the position of the rearend is the most critical issue that determines how much pinion angle will be needed. Some types of rear suspensions offer more control than others and require different angles. According to Bickel, a ladder-bar suspension normally requires ½ degree of pinion angle, a four-link requires 1-2½ degrees, and a leaf-spring suspension requires up to 6 to 7 degrees. In all examples, we’re talking about negative pinion angle, i.e., the pinion is nose-down in relation to the driveshaft. Bickel says a straight driveline delivers the most power to the rear wheels. For more on race car chassis tuning, Bickel offers classes as well as detailed books on the topic

Read more: http://www.carcraft.com/howto/91758/#ixzz26NNMQWXL

[RSWANNABE]

Well I have a minute to explain some thoughts and give some insight to my experience.

First I am part of a team that regularly races small tire stuff 26X10 and we do it with a stick shift & standard clutch setup. I have spent many many hours under a car measuring and wrenching to setup a car that leaves the line at 7,000 rpms and regularly 60's 1.26-1.27 on the rear tires. I can tell you that the pinion angle drastically effects the way the car leaves. We have plotted the car so we know exactly where the instant center, anti-squat and use those as tools, but a degree or two in the pinion angle makes the launch either work or not work. It is pretty noticeable the change in pinion angle and the effect on the hit of the tire that happens. You can adjust the pinion angle and watch the hit on the tire move. Meaning that the hit occurs behind the contact patch at the contact patch or in front of the contact patch.

A change in the front ride height will change the instant center and anti-squat as well as a degree or more in the pinion angle. The car quits leaving and in order to bring the launch back to where it was before front ride adjust, it is necessary to bring the pinion angle back into our known good number.

Depending on the thread pitch of the control arms 1 turn makes no difference to the ride height but it will change the pinion angle by a huge amount. I will have to disagree with your statement that it has nothing to do with traction and it is only a result of the other correct settings. You can achieve the same other settings and have a pinion angle of +4 degrees. I will race you all day that way no problem.

Usually when people can't understand these things they usually resort to some HUGE unnecessary over sized tire on their car to cover up their lack of understanding and knowledge. These are the ones that are the most fun to beat up on, with a little tire, properly setup stick shift car.

Have a great day.

P.S. it may be sometime before I check back on this thread please don't think that I ran away, as mentioned before I am just extremely busy.

[igotaneed4speed]

Well I have a minute to explain some thoughts and give some insight to my experience.

First I am part of a team that regularly races small tire stuff 26X10 and we do it with a stick shift & standard clutch setup. I have spent many many hours under a car measuring and wrenching to setup a car that leaves the line at 7,000 rpms and regularly 60's 1.26-1.27 on the rear tires. I can tell you that the pinion angle drastically effects the way the car leaves. We have plotted the car so we know exactly where the instant center, anti-squat and use those as tools, but a degree or two in the pinion angle makes the launch either work or not work. It is pretty noticeable the change in pinion angle and the effect on the hit of the tire that happens. You can adjust the pinion angle and watch the hit on the tire move. Meaning that the hit occurs behind the contact patch at the contact patch or in front of the contact patch.

A change in the front ride height will change the instant center and anti-squat as well as a degree or more in the pinion angle. The car quits leaving and in order to bring the launch back to where it was before front ride adjust, it is necessary to bring the pinion angle back into our known good number.

Depending on the thread pitch of the control arms 1 turn makes no difference to the ride height but it will change the pinion angle by a huge amount. I will have to disagree with your statement that it has nothing to do with traction and it is only a result of the other correct settings. You can achieve the same other settings and have a pinion angle of +4 degrees. I will race you all day that way no problem.

Usually when people can't understand these things they usually resort to some HUGE unnecessary over sized tire on their car to cover up their lack of understanding and knowledge. These are the ones that are the most fun to beat up on, with a little tire, properly setup stick shift car.

Have a great day.

P.S. it may be sometime before I check back on this thread please don't think that I ran away, as mentioned before I am just extremely busy.

So you agree that you changed pinion angle by changing the length of the control arm? Since you've plotted the car you also know that if you change the length of the control arm you move IC and rise % correct? So when you say your adjusting pinion angle your actually changing the length of the lowers or upper depending which you chose to adjust on, i would assume the uppers, if you moved the lowers now you changed wheel base and changed the cars scaling as well.

Now I can see how you might be mistaking drive train loss from a incorrect pinion angle as something that effects traction. Especially after you change pinion angle an see the 60ft increase due to a zero alignment and getting the best power transfer thru the drive line with minimal loss, Which has NOTHING to do with traction. You simply made the drive line happy an now its transferring all its energy in rotational force vrs losing some by ob-longed rotations of the u joint.

Also ride height is controlled by the springs, it has nothing to do with control arm length or pinion angle.


Here is a video (compliments of banjo on Yellowbullet) Showing a leaf spring car's drive shaft during a pass. Notice the spring wrap and how a adjustment in pinion angle would counter this, transferring more power thru a straighter u joint mean the joint actually travels less distance to make the rotation which means more power to the rear tires which will increase 60'. It will not make the car have more "traction"

http://www.flickr.com/photos/simpkinsfamily/7387713670/

[wikdsvt]

SO for a stock leaf suspension car can I do the following and it will be close:

1. Measure the pinion angle and compare it to the angle of the leaf spring mounts on the STOCK axle.
2. Transfer those measurements to the new axle
3. Weld in the leaf spring mounts

[igotaneed4speed]

SO for a stock leaf suspension car can I do the following and it will be close:

1. Measure the pinion angle and compare it to the angle of the leaf spring mounts on the STOCK axle.
2. Transfer those measurements to the new axle
3. Weld in the leaf spring mounts

If it was mine I would set it at ride height with the suspension loaded, this would be tricky as you would have to use two jack stands, one for each leaf spring and then block the front of the car up under the tires to get it high enough to work under. Unless the axle hangs under the leaf springs then you would have to find some way to support the leafs with four jack stands, two per leaf one in front of and one behind the axle and hold the axle up with a jack

Check engine angle, put the new rear end and perches in un-welded, set pinion angle, make sure its square then tack them on the axle. Verify pinion angle is where you wanted it, and the rear end is square still. Then weld it all up.

[QWKSLVR]

Where the fuck is Dave Zimmerman?? He's the sponsered chassis expert, right??

[Team Z Motorsports]

Where the fuck is Dave Zimmerman?? He's the sponsered chassis expert, right??

This is a good argument, and I save my arguing for the grudge section!

No one can offer real proof of either side of the argument. "Does pinion angle effect traction." If you ask drag racers you will get mixed OPINIONS If you ask stock car and dirt track racers the will say it defiantly effects traction, but unless you have a traction Dyno you cant quantify that a pinion angle change, changes traction. I will say that it does change drive line bind and bind does affect traction. So is it the pinion angle or the bind?
I will also say that when you change pinion angle it does change the length of the arms, but the amount is to insignificant to change the IC. That is unless you are swinging the pinion angle 10 degrees, but I don't think anyone here is talking more than 2-3 degrees, which with a standard 3/4-16 heim that is only .225 of an inch and a .225 inch change in arm LENGTH will not net a significant change in IC.

Ive seen this argument plenty of times over the past 10 years and nobody has proved it either way. It's not really worth arguing over, the best thing I can say is go to the track and keep adding negative pinion angle until you get a result,(that could be a wheelie, better 60' time or a drop in MPH, but a result) I've done it plenty of times you will learn something from it.