by "BaconSandwich is tasty." (baconsandwich)
Published 03/11/2017 at 01:45
by "BaconSandwich is tasty." (baconsandwich)
Published 03/11/2017 at 01:45
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STARS: 2
I’ve seen a few of these old videos, but I hadn’t seen this one before:
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One thing I’ve been curious about - independent suspension, especially in the rear of a vehicle. According to this video, using something like a universal joint isn’t enough to keep motion fluid if input and output angles are different:
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So, in the case of output coming from a differential and having to work it’s way to a wheel in an independent suspension setup, it must be necessary to use a pair of CV joints - one close to the differential, and one close to the wheel. Am I right?
"BaconSandwich is tasty." (baconsandwich)
03/11/2017 at 01:45, STARS: 1
I think this more or less confirms what I was thinking:
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"DC3 LS, will be perpetually replacing cars until the end of time" (dc3ls-)
03/11/2017 at 01:56, STARS: 0
I mean, I don’t think I’ve ever seen a CV axle that only had one joint.
"jimz" (jimz)
03/11/2017 at 08:21, STARS: 3
yes. you need CV joints because as you noted a simple Cardan (universal) Joint can’t tolerate too much of an angle between the output and driveshaft. You will get vibration and binding because the output and driveshaft will be trying to rotate at different speeds depending on the position of the joint.
Axle half-shafts need two CV joints for a couple of reasons:
1) the output/differential is in a fixed position, either attached to the transaxle (FWD/rear engine RWD) or to the body/cradle (RWD.)
2) the driven wheels need the ability to turn freely (FWD) and maintain controlled camber angle as they go through suspension travel (FWD/RWD.)
in a RWD vehicle, you can use a single CV joint per side (at the differential end) if the rear suspension is a swing-axle setup:
But swing axle suspensions suck for any kind of performance car application because the tires go through an immense amount of camber change through the suspension travel, and under hard cornering or braking can cause a phenomenon called “jacking” (
giggity
) which is one of the reasons the early Chevy Corvair was known for dangerous snap oversteer (sudden loss of rear-tire grip):
an interesting side note: Cadillacs up through the ‘70s used double Cardan Joints on their driveshafts as an inexpensive CV joint to improve drivetrain smoothness.
"Trevor Slattery, ACTOR" (anacostiabikecompany)
03/11/2017 at 10:24, STARS: 2
Career Triumph Spitfire owner here.
There are easy ways to address it with our cars. But yeah...it is a SLIGHT issue with the stock suspension setups. lol. I got caught in a snow storm in mine. Ended up on someones front lawn. Good times.
"BaconSandwich is tasty." (baconsandwich)
03/11/2017 at 14:41, STARS: 0
That’s an excellent description of the problem. The one situation where I think a person could get way with Cardan joints is if it was double-A arm suspension that kept the wheel exactly parallel throughout the full range of motion. I understand that this is actually a bad thing, though, as you actually want some camber, as during corning, it helps to keep a larger contact patch.
It does make me wonder - for guys doing off-road independent suspension, how do they decide what parts to go with? A bit of trial and error? I suppose it all depends on the vehicle being modified, spline styles, etc.
"BaconSandwich is tasty." (baconsandwich)
03/11/2017 at 14:42, STARS: 0
That’s crazy! :P
"Trevor Slattery, ACTOR" (anacostiabikecompany)
03/11/2017 at 14:55, STARS: 0
Well the guy in the picture also lifted mid-corner. They make an old 911 look stable when it comes to life throttle oversteer.