Gweesh

A question for the rear axle gurus here.

Am I missing something or does it seem like a heck of a lot of force gets applied to the side yoke snap ring in corners? Why would they not have designed this IRS with an upper locating strut? Seems like I'm missing something.....

SH-60B

I agree, but others say the weight of the car prevents any force pulling the side yoke out, only force pushing it in on the center pin. The tips of the yokes can wear from that.

toobroketoretire

The only time there is a load on the snap ring is when the car leaves the ground. So unless you're trying to duplicate the Dukes Of Hazard stunts you have nothing to worry about.

bashcraft

My '69 didn't have the snap rings installed when I bought it in 1979 and I never put them in. Never had a reason too.

TheSkunkWorks

Budgetary constraints were a significant factor in the C2/C3 IRS design. There have been aftermarket suspensions introduced that take the half-shaft out of the equation - some thought out better than others - and a number of C4 based IRS refits have been done.


Side yoke endplay does indeed effect dynamic rear camber. And, while I can't put my finger on it just now, indisputable video evidence has been posted previously here on the CF which illustrates during hard cornering there is enough force to noticeably pull the yoke outwards, resulting severe (even dangerous) positive camber at the outer rear wheel.



TSW

pauldana

see video below

Again... you are so freggin wrong





I fought this battle before, and won:-)

Below are the thread to prove my point

C3 clips rear end

https://www.corvetteforum.com/forums...mike-ward.html


https://www.corvetteforum.com/forums...-rear-end.html

bashcraft

You left the part out about the car being on racing slicks. This wouldn't happen on street tires.

pauldana

The above video, although racing, is NOT using slicks






Copy and past from one of the threads pointed out via me


round 3 is here..... new evidence from the holy grail itself... GM...

This was taken from a post from David_at_triumph a forum member commenting on the same thing on a different thread...

seems the "C" clip guys win once again...

Quoit from David:
I also would like to set the record straight on the great snap ring debate. From the 1963 corvette SAE paper explaining the new IRS, there is a cutaway of the differential and the caption reads:

"Suspension thrust in one direction is taken by snap rings located on the splined end of the short integral yoke drive shafts. Thrust in the opposite direction is through the yoke unit to the differential pinion shaft".

Pretty clearly, the engineers were expecting thrust in both directions. And yes, they did intend the snap rings to both hold the load and act as a bearing. Incredulous as it seems, every design engineer is tempted by the forbidden fruit of the snap ring - I am one and I see it all the time. If you have a car like mine with worn side yokes and an otherwise race prepped chassis, you can certainly feel it. I have a long weekend ahead of me (sic). And I did not intend this email to "pile-on" anyone. Often times designers are worked into a spatial corner, probably with a bad initial assumption that a static analysis would indicate, too late to change the surrounding pieces, and viola, what was once an oversight is cured with a skinny groove and the magic of a snap ring, a feature by golly.
The cross-section with the differential and the quote is on this page:

http://www.web-cars.com/corvette/196...er.php?page=10

A conspiracy assumes I actually know someone. I don't. My only motivation is trying to figure out what is happening with my car and eventually how to permanently solve it.

The loading diagram that Mike is after is on page 5 - it only shows the outboard wheel in a turn in a static condition. I think by watching the video it is pretty clear that the loading is anything but static. If you watch carefully, as soon as the tire rolls from its inside edge (where the static load analysis is applied) to a condition where the load transfers to the outer edge due to hard cornering (or when the suspension is in rebound and the tire is camber outward), this pulls the top of the tire outboard and this is when the snap rings limit the motion.

static load diagram:
http://www.web-cars.com/corvette/196...per.php?page=5

camber diagram for rear wheels, anything over 1" of rebound movement results in the rear wheels being camber out.
http://www.web-cars.com/corvette/196...er.php?page=10


Way to go David!
http://forums.corvetteforum.com/c3-t...utoxing-3.html

bashcraft

You can call them whatever you want, but they are not your average street tires.

BlackC3vette

[QUOTE=bashcraft;1591117527] You can call them whatever you want, but they are not your average street tires.[/QUOTE

It would be great to see your video with street tires preventing those dynamic loads in the corners and prove your opinion.

pauldana

[QUOTE=BlackC3vette;1591117719]I road race... So yes, very important to me...

guess if your a cruiser, then yes... does not matter,,,,,,

GM put them there for a reason other than just assembly... so they must have though different also..

bashcraft

Like I said, I've owned my car for 36 years. It's never had the clips installed and I've never once had a camber issue in a hard corner.

BTW, I was 19 when I bought my car, so it has been driven hard.

BlackC3vette

Does that mean no cool video?

pauldana

Ever competitively raced? Get that on a track and in a corner, and you will be off the track in a bad way...

sure you had a lot of fun as a kid like i did:-) but it is not safe to have this happen...

if Trackdog2 (mike) chimes in, he will verify my view... and he is well known here as the authority on rear ends...

if you read the other post i showed, you will find he agrees with me, as do several others that work in the area.

bashcraft

My point is, this isn't an issue with street tires. Racing tires are a completely different story but you guys don't seem to comprehend that. Or maybe you're so intent on "winning the argument", that you just ignore it and hope no one notices.

pauldana

Maybe not 15" truck tires that they offer for our vettes now.... but ANY modern handling tire with a tread ware below 300 will do this,,, does not have to be a slick...

So, again,,, for those 15" C3 cruisers, fine... to anyone wanting to have performance and moved into a 17 or 18" rim ..... no....

76Rat

Can you explain exactly why it would not be a problem with street tires?

redvetracr

I`m not a diff guru (I`ll leave that to Mike & Gary) but I would never dream of driving any Corvette without side yoke clips.

bashcraft

What do you think would happen if you did?

homestead

I wouldn't want my car even thinking of doing that on the street or racing with street tires or slicks! It just looks unsafe...