That is a very short 4 bar.....any drawbacks to a setup that short. Im about to do a nash metropolitan and there is very little room back there. Sent from my SM-G975U using The H.A.M.B. mobile app
Gearhead - On one hand, yes, it will work, on the other hand it will be somewhat harsh riding. That is, the bumps in the road will be felt as harder, that is, if the bars were longer, the movement would be less stiff feeling. And yea, the wishbone will work well, just make SURE that there is a little "extra" movement in the slider in the "shortening" direction. In your picture, it looks pretty close to being solid, or bound up. I would also add a couple of side supports on the wishbone mount brackets. Remember, that little 1/8" thk. bracket material is all that there is holding your car body centered over the chassis. Mike
The wheelbase on the metropolitan is only 85 inches so im sure it will be a little harsh riding anyways. Im gonns try to stretch it as much as I can since I gotta stretch the tiny wheelwells anyways Sent from my SM-G975U using The H.A.M.B. mobile app
Very neat set up....something to consider for sure. One idea to simplify this design would be to get rid of the upper 4 bar links, flip the wishbone 180, make it solid and use a big Johnny Joint on the front wish bone mount. The rearend would still be free to articulate 30 degrees and you'd have fewer moving parts. Sent from my SM-G950U using The H.A.M.B. mobile app
Lotsa work (note above) for no real change in the ride quality. Need to severely stiffen the three wishbone link brackets over simple stiffeners as I noted above. I'd just lengthen the four bar as much as possible (a "gearhead" has noted), to help smooth the ride quality. Mike
I guess I'm too lazy.... Id just triangulate the upper arms, get rid of all the extra weight, work and parts and call it a day....
I like the wishbone. If I did one like that I'd put a Zerk fitting on it so I could lube it. Anything that moves does better with lubrication. ( I know that statement is the lead in to a million and one jokes but what the hey!)
If there isn't an issue with the axle taking part of the driving thrust at the top of the pumpkin, there isn't even any need to flip the wishbone. And even a big Heim/Rose should do the job, as in an on-road application we'd be unlikely to see more than 6°-7° of angular misalignment overall. So should a properly-sized IFS ball joint. With a conventional high-roll-centre live-axle setup there is a lot to be said for having the RC move with the axle. Rear lateral weight transfer is more a factor of RC height than rear roll stiffness in that kind of setup, so there is more sense in keeping the height of the RC above the road constant through suspension travel than keeping the height of the CG above the RC constant. We can't keep both constant. Conversely we could turn the setup upside-down and make it a lower wishbone and upper links: nothing wrong in principle with that, though there it makes sense to have the apex of the wishbone forward and pivoting on the frame, because we'd be tuning the rear suspension by varying the roll stiffness, so we'd rather want to keep the height of the CG above the RC constant. There are good reasons to have a general baseline preference for RCs as low as possible, regardless of the type of suspension: minimize jacking forces, minimize lateral components of roll motions, and maximize the effect of roll-stiffness tuning.
I'm not sure of the relevance to the original question now, but to my eyes the wishbone ought to have the two forward mounts parallel to the axle. If you can imagine the wishbone not attached to the axle and you were swinging it up and down the joints would be binding with them angled like that. There may be an opportunity to lose some of the parts by making a modified version of the wishbone and deleting the upper 4 bar links, but maybe that would be low power street mods, for a racing car better stick with what is tried and tested. Just some random thoughts. Mart.
True that: I didn't spot it. BTW I've just been watching your front-end assembly videos. Very educational; thanks!
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