Rear Suspension Spherical Bearings
Jun 23, 2011, 12:13 PM
#1
Rear Suspension Spherical Bearings
I'm considering replacing some of the rear bushings with spherical bearings. Has anybody on here done this that can give some feedback on how well it works?
I'm primarily interested in auto-x and since auto-x relies pretty largely on low speed acceleration I'm concerned about how this will effect shock loads on the tire. Will replacing the trailing arm bushing lead to reduced low speed traction and increase the chance of drivetrain failure from higher shock loads?
I'm primarily interested in auto-x and since auto-x relies pretty largely on low speed acceleration I'm concerned about how this will effect shock loads on the tire. Will replacing the trailing arm bushing lead to reduced low speed traction and increase the chance of drivetrain failure from higher shock loads?
Jun 23, 2011, 12:18 PM
#2
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I'm considering replacing some of the rear bushings with spherical bearings. Has anybody on here done this that can give some feedback on how well it works?
I'm primarily interested in auto-x and since auto-x relies pretty largely on low speed acceleration I'm concerned about how this will effect shock loads on the tire. Will replacing the trailing arm bushing lead to reduced low speed traction and increase the chance of drivetrain failure from higher shock loads?
I'm primarily interested in auto-x and since auto-x relies pretty largely on low speed acceleration I'm concerned about how this will effect shock loads on the tire. Will replacing the trailing arm bushing lead to reduced low speed traction and increase the chance of drivetrain failure from higher shock loads?
Jun 23, 2011, 01:10 PM
#3
There is no reduced low speed traction and any increased shock load associated with spherical bushing replacements alone. If anything low speed tration will increase because you are reducing dynamic lateral movement resulting from rubber deflection.
With that said, if autocross is the purpose of the change you need to be aware of two things:
1) sphericals have a much shorter life and require frequent servicing to avoid noise and binding. So, they are no recommended for a car that serves a lot street duties.
2) Make sure that you are aware of where such a change will land you in the classing. They are not alowed until SM and anybody familiar with the sport will tell you that SM stands for Serious Money. You don't want to be in a class that you can't be competitive because of a foolish mod.
With that said, if autocross is the purpose of the change you need to be aware of two things:
1) sphericals have a much shorter life and require frequent servicing to avoid noise and binding. So, they are no recommended for a car that serves a lot street duties.
2) Make sure that you are aware of where such a change will land you in the classing. They are not alowed until SM and anybody familiar with the sport will tell you that SM stands for Serious Money. You don't want to be in a class that you can't be competitive because of a foolish mod.
!
Jun 23, 2011, 02:00 PM
#6
Haha, yeah, I've always ran in Street Mod with a goal of eventually being at class minimum weight on a 275 tire and a complete looking interior.
Madmax, are you running a spherical bearing setup in the rear?
Madmax, are you running a spherical bearing setup in the rear?
Last edited by 03whitegsr; Jun 23, 2011 at 02:09 PM.
Jun 24, 2011, 06:04 AM
#7
I'm evoless right now and I've been playing in CSP with the miatas in my wife's ex daily driver(an audi TT). However, it's only a matter of time before I jump back into another one, maybe a X.
When I was in XP with the evo, I entertained the idea of sphericals but their street life is so short and they are too high maintenance for me. I always did full delrin replacements because they are also SP legal and I've been pretty pleased with the results. The latest delrin bushing that I just prototyped for the TT before production has inner grease grooves that makes them perfect for a car that's also driven in the streets.
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When I was in XP with the evo, I entertained the idea of sphericals but their street life is so short and they are too high maintenance for me. I always did full delrin replacements because they are also SP legal and I've been pretty pleased with the results. The latest delrin bushing that I just prototyped for the TT before production has inner grease grooves that makes them perfect for a car that's also driven in the streets.
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Jun 24, 2011, 12:42 PM
#8
Nice, I'll probably do delrin in the upper rear control arm due to how the mounts are setup.
One thing that concerns me with delrin replacements though is that they restrict the arm to only one degree of freedom and often times, you will get other rotations due to the other arms in the suspension. The EVO for example, the lower rear control arm doesn't go straight up and down because of the trailing arm. The trailing arm will induce high stresses in the bushings where the sphericals will not induce those stresses and they reduce the amount of stiction in the system. All mounted up, my front control arm flops around like a wet noodle.
I've heard the sphericals last pretty well when used with the PTFE liners? Don't know how true it is but the PSRS uses the PTFE lined bearings and people have reported they hold up well on the street on here.
One thing that concerns me with delrin replacements though is that they restrict the arm to only one degree of freedom and often times, you will get other rotations due to the other arms in the suspension. The EVO for example, the lower rear control arm doesn't go straight up and down because of the trailing arm. The trailing arm will induce high stresses in the bushings where the sphericals will not induce those stresses and they reduce the amount of stiction in the system. All mounted up, my front control arm flops around like a wet noodle.
I've heard the sphericals last pretty well when used with the PTFE liners? Don't know how true it is but the PSRS uses the PTFE lined bearings and people have reported they hold up well on the street on here.
Last edited by 03whitegsr; Jun 24, 2011 at 12:52 PM.
Jun 24, 2011, 02:14 PM
#9
Yes, booted sphericals handle the elements better but they are still not suited IMO to normal extended street duties. Delrin, as you pointed out, works best when mounted in articulation that moves in a single axis. However, if that articulation only saw multi axial movement because of rubber deflection it could be eliminated with a solid bushing without a problem.
Jun 24, 2011, 05:58 PM
#10
Evolved Member
My whole car has just about been converted over to spherical bearings, only a few i've left factory as I think they are good enough stock.
I designed some myself and bought some off the shelf, they all run good teflon lined bearings and are still going good 2 years off, ok, the car isnt a daily driver and only gets taken out to go on the circuit but they haven't given me any hassles, and also I didn't notice any increase in noise or vibration, but that could be because i'm driving an RS so its already noisy.
I designed some myself and bought some off the shelf, they all run good teflon lined bearings and are still going good 2 years off, ok, the car isnt a daily driver and only gets taken out to go on the circuit but they haven't given me any hassles, and also I didn't notice any increase in noise or vibration, but that could be because i'm driving an RS so its already noisy.
Jun 24, 2011, 06:11 PM
#11
I put sphericals in the lower front lateral arms of a daily-driven and autocrossed 2G DSM. I did this because I was convinced I was losing front camber to "bushing squish" (the stock rubber bushings were quite large). I have no idea if I was correct, but after one winter they had to come out and I just put in some ES bushings, since they were OTS and I had no desire to do this much work every year. I think both moves were very silly. The sphericals on a daily driven car in a serious salt-and-sand area was dumb. The ES bushings were crap. I should have done what the New England DSMers did: Delrin in the same ratio as stock so the car could be in ESP and also not need a ton of work every spring.
Cliff notes: +1 on Delrin, instead.
Cliff notes: +1 on Delrin, instead.
Jun 24, 2011, 08:53 PM
#12
Yogi, did they have a noticeable impact on cornering performance? Either overall improvement or more consistency in handling behavior?
Iowa, yeah I bet salt would make quick work of them. I don't see my car going out in the salt, probably won't ever see any rain either. Or if it does, everythin will probably get some WD-40 or something immediately after to force the water out of all of the bearings.
I'm sure it will be a hassle, but the car doesn't see a ton of miles so it shouldn't be too bad?
Iowa, yeah I bet salt would make quick work of them. I don't see my car going out in the salt, probably won't ever see any rain either. Or if it does, everythin will probably get some WD-40 or something immediately after to force the water out of all of the bearings.
I'm sure it will be a hassle, but the car doesn't see a ton of miles so it shouldn't be too bad?
Jun 24, 2011, 09:07 PM
#13
Well, in that case, I'd say go for it, but now I have to ask: why the rears? Assuming pillowballs on the front struts, I'd wager you'd get the best improvements from sphericals on the lower-front arms. Maybe it was all in my head, but I thought that turn-in was much better for the one summer I had them on the DSM.
Jun 25, 2011, 07:22 AM
#14
Well, in that case, I'd say go for it, but now I have to ask: why the rears? Assuming pillowballs on the front struts, I'd wager you'd get the best improvements from sphericals on the lower-front arms. Maybe it was all in my head, but I thought that turn-in was much better for the one summer I had them on the DSM.
Thanks for being gentle.