Trailing Arm Spherical Bearing |
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Trailing Arm Spherical Bearing |
yeahmag |
Jan 21 2020, 03:25 PM
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#1
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Advanced Member Group: Members Posts: 2,421 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California |
It seems to me that the trailing arms are ripe for a spherical bearing mod. The way the rear toe is set leaves much to be desired, even with (if not more) with Delrin/Teflon bushings.
Has anyone tried to modify the inner ears to allow for a spherical bearing? |
Mark Henry |
Jan 21 2020, 03:56 PM
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#2
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
I think it's been done in needle bearings, I have McMarks Full Motion fronts that are NLA.
Elephant has the ploy/bronze bushings with grease zerks that include the shafts. |
yeahmag |
Jan 21 2020, 04:01 PM
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#3
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Advanced Member Group: Members Posts: 2,421 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California |
I have the Rebel Racing units and while they are great, I cringe at the idea of running such a small thrust surface as I increase toe in. You can envision how the thrust surface gets smaller and smaller as the angle increases. Now think about the forces I'm putting through it on A7's!
For a long time I thought about self aligning washers (which I use on the RR front teflon bushings for collinearity), but it seems that lots of work would still need to be done to get those to fit. A simple spherical bearing would be an easy fix, especially if someone already has an ovaled out inner ear. |
sixnotfour |
Jan 21 2020, 04:06 PM
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#4
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914 Wizard Group: Members Posts: 10,419 Joined: 12-September 04 From: Life Elevated..planet UT. Member No.: 2,744 Region Association: Rocky Mountains |
Armondo's GT build has em,, "914-6 GT pbase" https://pbase.com/9146gt/image/25824874
needs more surface area..ie bushing or roller bearing.....IMHO http://forums.pelicanparts.com/porsche-914...-project-3.html Attached image(s) |
Mark Henry |
Jan 21 2020, 04:12 PM
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#5
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Armondo's GT build has em,, "914-6 GT pbase" https://pbase.com/9146gt/image/25824874 needs more surface area..ie bushing or roller bearing.....IMHO (IMG:style_emoticons/default/smile.gif) https://pbase.com/9146gt/image/36445933 |
jd74914 |
Jan 21 2020, 04:47 PM
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#6
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Its alive Group: Members Posts: 4,780 Joined: 16-February 04 From: CT Member No.: 1,659 Region Association: North East States |
I've done that. Haven't driven yet, but check out my build thread.
http://www.914world.com/bbs2/index.php?showtopic=227430 (IMG:http://www.914world.com/bbs2/uploads/post-1659-1419972757.jpg) (IMG:http://www.914world.com/bbs2/uploads/post-1659-1419972774.jpg) (IMG:http://www.914world.com/bbs2/uploads/post-1659-1419972782.jpg) |
jd74914 |
Jan 21 2020, 04:51 PM
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#7
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Its alive Group: Members Posts: 4,780 Joined: 16-February 04 From: CT Member No.: 1,659 Region Association: North East States |
Sorry, can't find pictures of the real parts for some reason. (IMG:style_emoticons/default/screwy.gif)
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yeahmag |
Jan 21 2020, 04:55 PM
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#8
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Advanced Member Group: Members Posts: 2,421 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California |
Very cool! Is the new rod running through the trailing arm fixed in someway to the arm itself?
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tygaboy |
Jan 21 2020, 04:59 PM
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#9
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914 Guru Group: Members Posts: 5,282 Joined: 6-October 15 From: Petaluma, CA Member No.: 19,241 Region Association: Northern California |
My buddy Martin was over the other day looking at my Tangerine rear pick up point install and he asked "why don't you add a spherical bearing at the end that "adjusts"?
He used to design and fab ProStock drag bike frames for Kosman so has experience with Harley stuff and he pointed me at the Harley Soft Tail swing arm bearing, of all things. Pictured below. It would require fabbing a "cup" that would weld to the suspension ear, house the bearing and secure it with a circlip. Something to consider, anyway. Attached image(s) |
Mikey914 |
Jan 21 2020, 06:17 PM
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#10
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The rubber man Group: Members Posts: 12,649 Joined: 27-December 04 From: Hillsboro, OR Member No.: 3,348 Region Association: None |
We are actually working on a similar product right now. We are in machining right now.
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yeahmag |
Jan 21 2020, 06:21 PM
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#11
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Advanced Member Group: Members Posts: 2,421 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California |
Well then. Let me know if you need some severe duty testing!
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Superhawk996 |
Jan 21 2020, 06:41 PM
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#12
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914 Guru Group: Members Posts: 5,777 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
No spherical for me for street use - no thank you
For racing use sure. |
jd74914 |
Jan 21 2020, 10:19 PM
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#13
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Its alive Group: Members Posts: 4,780 Joined: 16-February 04 From: CT Member No.: 1,659 Region Association: North East States |
Very cool! Is the new rod running through the trailing arm fixed in someway to the arm itself? It’s not quite like that in real life. The tube running through the middle is representative of the trailing arm tube with the rolled lips removed. The other parts are then welded into an assembly for each side which was then pressed into the trailing arm and TIG welded around the perimeter. |
Jeff Hail |
Jan 21 2020, 10:56 PM
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#14
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Senior Member Group: Members Posts: 1,141 Joined: 3-May 07 From: LA/ CA Member No.: 7,712 |
My buddy Martin was over the other day looking at my Tangerine rear pick up point install and he asked "why don't you add a spherical bearing at the end that "adjusts"? He used to design and fab ProStock drag bike frames for Kosman so has experience with Harley stuff and he pointed me at the Harley Soft Tail swing arm bearing, of all things. Pictured below. It would require fabbing a "cup" that would weld to the suspension ear, house the bearing and secure it with a circlip. Something to consider, anyway. Why not a bolt on solution that's simple and doesn't have a lot of moving parts? Well at least for the folks that have modified the pickups already. Toe in and toe out on both the inner and outer pivots as well as camber adjustment on both ends. Attached thumbnail(s) |
914forme |
Jan 22 2020, 10:41 AM
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#15
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Times a wastin', get wrenchin'! Group: Members Posts: 3,896 Joined: 24-July 04 From: Dayton, Ohio Member No.: 2,388 Region Association: None |
(IMG:style_emoticons/default/agree.gif)
Even for a stock outer that would work. Flip the bracket over. Rod ends have some advantages in this application. Ready avlibility, easy R&R, heck don't even need to remove the arm to replace the bearing, all win win in my book. Inside becomes a bit of an issue, but plenty of bearings to do just that at the local farm supply store. In reality, I would Move the bearing into the arm on the inner side and let it go. "Very cool! Is the new rod running through the trailing arm fixed in someway to the arm itself?" the bearing would turn ssepart of the arm shaft, just like it does not. These are the exact same. So now what are we missing. Roller bearings in the arm make pvferct sense as it keeps the arm and the bearing and shaft all in alignment. The issue is the angle at the end. Just use two pieces maybe 4 to solve the problem. Since you want the nut o the shaft to be seated flat to keep your settings. a semi circle washer with corresponding cup, on both sides solves your issue, and keeps everything working correctly while providing the movement you desire from the arm. You may need some thrust bearings on the outside. Muellers kit had them, and then everything works perfectly. Look something like this. Concept, not final engineered solution. BTW, that will cost you roughly $25K in consulting if you use the design or idea. (IMG:style_emoticons/default/shades.gif) |
Toby |
May 25 2020, 09:30 PM
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#16
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Newbie Group: Members Posts: 9 Joined: 22-February 13 From: Rochester, Indiana Member No.: 15,566 Region Association: Upper MidWest |
I'm trying to find the geometry of the rear swing arm and got good info from seeing Jeff Hail's setup. I don't have a 914 but I want to duplicate it's suspension movement, using a bearing and brake from a Pontiac Bonneville SSEi and the drivetrain (mid engine mount).
I'm hoping that you would evaluate the geometry as is for the 914 and make any suggestions for improvement. Questions I have are camber and caster, toe in and out, does the frame mount horizontally or is there a different angle from the plane of the wheels? For a street machine are rubber bushings the way to go or does it need the precision of needle. I've read the above posts and hope you guys will direct me to a thread, if this is not a good place to ask for some engineering help. Thanks |
mbseto |
May 26 2020, 02:26 PM
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#17
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Senior Member Group: Members Posts: 1,253 Joined: 6-August 14 From: Cincy Member No.: 17,743 Region Association: North East States |
Maybe a dumb question but is the goal to
1) allow this to float all the time OR 2) just allow it to be locked into place after toe adjustment without putting a constant stress on the ear ? |
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