11Budlite Posted January 21 Posted January 21 That reinforcing plate is designed to limit the twist in the axle. I think that plate and other similar designs was introduced to reinforce the early Triumph axles. I guess it's effectiveness is determined by how much hp/torque you put through the axle and how grippy the tires are. I'm not sure if that reinforcement was necessary on the Escort axles introduced in the late 60's, or the Morris Ital axle introduced in the 80's. If you want to read into this a bit further you can check out these links from the Simple Sevens site. Lot's of photos with different methods of reinforcing the Triumph axle. I'm not an expert on these so I don't know if the later Escort or Ital axles could be reinforced in the same manner, or if it would even be required. https://www.simplesevens.org/history/t10axle/t10axle.htm https://www.simplesevens.org/dsk/bulletins/axles1.htm
MV8 Posted January 21 Posted January 21 2 hours ago, 11Budlite said: I think this is the twist being discussed. It's a well known issue on live axle Lotus Sevens. https://www.super7.dk/rearaxle.html Yes, that is what I am referring to. Thanks for sharing. I'd not seen that drawing. 1
IamScotticus Posted January 22 Author Posted January 22 4 hours ago, 11Budlite said: I think this is the twist being discussed. It's a well known issue on live axle Lotus Sevens. https://www.super7.dk/rearaxle.html What a great resource. Thanks, Bruce 1
MV8 Posted January 22 Posted January 22 Only thing about the picture is the torsion arrow is pointing ccw for traction. Nobody is interested in how to fix this without welding on four feet of unsprung steel plate or tubing? Anyone? Anyone? Bueler? 1
11Budlite Posted January 22 Posted January 22 1 hour ago, MV8 said: Only thing about the picture is the torsion arrow is pointing ccw for traction. Nobody is interested in how to fix this without welding on four feet of unsprung steel plate or tubing? Anyone? Anyone? Bueler? I'm interested!
MV8 Posted January 22 Posted January 22 Great! I see Bruce and WDB are interested! This theory until someone does it but it is fun to discuss. The cars I've seen appear to have enough room between the tire and the chassis rail for a link to clear in roll. A spherical ended link is added below the axle outboard of the chassis tube, spaced to clear the chassis tube in roll. The A frame pivot bolt is replaced with one an inch or so longer and a 1/2 inch or so spacer is used. A drop brkt is clamped to the axle using either the U bolts or direct clamp slightly inboard. This type of clamp on axle brkt is easy to find. The length of the drop should place the eye at the same distance from the axle centerline as the diff A frame pivot and the link is adjusted to be the same length as the A frame. The brkt is lightly clamped, coilover removed, and the chassis supported at ride height, then each wheel is raised one at a time to let it rotate the brkt if needed. The brkt is then tightened and rolled again, trying to find the best spot for the link length and the brkt angle to minimize any potential bind in roll. Once satisified, the ubolts or clamp are fully tightened. The brkt can then be stitched to the axle tube if necessary to ensure it doesn't slip. Witness marks can help determine if it is slipping. Finding the best spot and link length that allows as much roll as the bushings do with the links is the goal. This is not the same as making it a four link. The added link is just an assist and should reduce the twisting to less than it would be with the heavy truss arrangements. The diameter of the A frame pivot bolt will determine the size of the sphericals and link tubing. The brkt can be fabbed from 1/8 to 3/16" strip depending on the design. I suggest double shear spherical mounting at the axle brkt.
anduril3019 Posted January 22 Posted January 22 Sounds interesting. Doesn't it effectively end up being a 4 link, with the A frame providing lateral location? Or are you thinking the added links wouldn't need to be as stout since they are sharing some of the work with the A frame?
MV8 Posted January 22 Posted January 22 Think of it like a chain/strap behind the axle that is only tight when the car is accelerating hard enough to start to twist/bend the housing and any other time it is dead weight. When sized based on the A frame bolt shank and tight on the axle, I expect it to be as strong as any other linkage, but when setup properly, it should do nothing but prevent the housing from being overloaded. I don't see how this suspension with good bushings can roll very much anyway, given the thin rubber and width on the outer links. If every bush was replaced with sphericals (or a trunion at the center), it may be tougher to setup or the roll may need to be limited. The location of the axle end of the link would take some initial trial and error. A four link generally needs equal length, parallel links to prevent binding in roll but it is also a question of how much roll is actually needed before it binds. Most older oem domestic live axles suspensions that I am familiar with bind to a degree which is partly why the bushings are huge and thick walled and the control is so sloppy. Given the packaging in a CAT, if a live axle is used, a torque arm design (i.e., similar to the '80s camaro/firebird) makes a lot of sense. The torque arm attachment must plunge to allow roll, so the spherical (located near the transmission mount) is sleeved to float in the arm, with one trailing arm on each side and a watts linkage since the car is so narrow.
pethier Posted January 22 Posted January 22 (edited) OK. The light is starting to come on. You are talking about the same force that causes S-shape wind-up in leaf-spring cars. I can see that the deDion setup cures this for the driveline, as the torque is imparted directly to the chassis at the diff. The forces will still be applied to the deDion tube under braking, because these cars have outboard disk brakes. Edited January 22 by pethier
anduril3019 Posted January 22 Posted January 22 12 minutes ago, pethier said: I still don't get it. With only three connections to the axle housing, these three points will always be in the same plane. How can a twist be imparted to the axle housing? Imagine removing the A frame connection at the diff housing, what would the axle do? It would pivot (twist) the entire axle around the radius arm connections on top of the axle. So, with the A frame connected, that twisting force is still present but is restricted by the A frame. What you're left with is a twisting force (spread across each half of the axle) between the upper radius arm connection point, and the lower A frame connection point. That's what the drawing above is trying to illustrate. It took me a little while to wrap my brain around it, but once you see it, it makes sense.
IamScotticus Posted January 23 Author Posted January 23 21 hours ago, anduril3019 said: wrap my brain around it, Lol 1
pethier Posted January 24 Posted January 24 7 hours ago, IamScotticus said: Lol Hey, you're talking about my SCCA Region!
pethier Posted January 24 Posted January 24 On 2/26/2022 at 9:50 AM, Croc said: Quick write up Thackery "Spring" Washers: JHPS Any weber specialist for parts supply will have them. Just realized I have always misspelled the name? https://www.jhps.com/mm5/merchant.mvc?Screen=SRCH&Session_ID=7ef2cb3a73d4e3859f6e35aaa5acb3e8
pethier Posted January 24 Posted January 24 (edited) On 2/26/2022 at 9:50 AM, Croc said: Duplicate, please delete. Edited January 24 by pethier
pethier Posted January 24 Posted January 24 2 minutes ago, pethier said: https://www.jhps.com/mm5/merchant.mvc?Screen=SRCH&Session_ID=7ef2cb3a73d4e3859f6e35aaa5acb3e8 and then search for thackery
MV8 Posted January 24 Posted January 24 On 1/22/2025 at 5:58 PM, wdb said: You need CAD. I have it on one of these old desk tops as a standalone where programs are now apps to be rented. I'd need the car to accurately measure. Easier just to do it since the cad will have errors and the fab will have errors/tolerances. I am a fan of R.C.A.D. though (rapid cardboard aided design).
pethier Posted January 24 Posted January 24 7 hours ago, MV8 said: I am a fan of R.C.A.D. though (rapid cardboard aided design). I believe that was my method to mount a 5-panel Wink mirror in my Lotus Europa. When I arrived at something that worked with two pieces of cereal-box cardboard, I traced these pieces onto aluminum sheet. Worked a treat for years. I used the corrugated stuff for the design of the pylon-redirector on my Seven, then brought that pattern to the Metal Supermarkets in Roseville MN to shear me a piece of 1/4" aluminum. I plan on lightening holes when I get around to it. 1
IamScotticus Posted January 24 Author Posted January 24 (edited) 19 hours ago, pethier said: Hey, you're talking about my SCCA Region! @anduril3019 made a pun. The subject was axle wrap. He said "wrap my head around it." It's still funny. Edited January 24 by IamScotticus
pethier Posted January 27 Posted January 27 (edited) On 1/24/2025 at 5:46 PM, IamScotticus said: @anduril3019 made a pun. The subject was axle wrap. He said "wrap my head around it." It's still funny. And I think it is funny that after many decades, the name of the SCCA Region in Minnesota and some parts beyond has a whole new meaning due to social media. Edited January 28 by pethier 1
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