I've got the Shakes!
05-05-11, 07:10 PM
#17
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Bon, is this the bushing to which you are referring? I just want to make sure this is the split bushing you recommend before ordering. http://lexus.sewellparts.com/accesso...2002/4558.html
Bon, you also mentioned that the SC and the GS had similar steering setups. Would you look at the attached link starting with thread #2 and tell me if this looks like ours?
https://www.clublexus.com/forums/sus...k-bushing.html Thanks for your help.
Bon, you also mentioned that the SC and the GS had similar steering setups. Would you look at the attached link starting with thread #2 and tell me if this looks like ours?
https://www.clublexus.com/forums/sus...k-bushing.html Thanks for your help.
Yes, the GS thread is exactly our steering rack and bushings. The first picture shows the Daizen bushings.
Based on my experience I'd rate the TM Engineering/Daizen bushings the best. The Sewell bushings in your link are polyurethane but the design appears to be a mid-range stiffness somewhere between OEM and the Daizen bushings. I have both Daizen and the Sewell aftermarket bushings in my possession so I've inspected both. I installed the Daizen when I had to make my decision and I don't have a single regret. I have to say it again: "Don't use the OEM bushings!" There, I feel better.
05-05-11, 07:19 PM
#18
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On the other hand, changing ball joints, inner and outer tie rods, adding wheel spacers or wheel offsets, camber, caster, toe in and tire air pressure all have a direct effect on steering effort.
10-22-11, 06:06 PM
#20
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Well, I'm about to declare my problem is fixed!! It's taken a while as I have a lot going on but I finally got back to troubleshooting today. I measured the runout of my wheels and tires and didn't see anything unusual. I then adjusted the free play in my steering rack and things felt a bit tighter but the shakes that I get starting at 65+ mph were still there. I removed both front wheels and cleaned up the hub centric 20 mm spacer, wheel and rotor just to be sure. No Joy.
And then, I rubbed my hand over the front tire and felt ridges, often called "feathering" or "sawtooth" of the tread blocks. Not enough to see but they can be felt. In my case the edges of the ridges can be felt as my hand sweeps over the tread toward the center line of the car.
The inner tread was also wearing faster than the rest of the tire. The inner wear is usually attributed to negative camber, and it can be, but when present along with the ridges that I could feel in the thread this is only one thing: Insufficient toe-in.
I've had several alignments, with printouts, so I'm sure that things were close to factory specifications but I have modified the front end with polyurethane bushings so things are stiffer than OEM.
I cranked in a couple of turns of toe-in and went for a test ride: The shakes are gone. Completely gone. I went as fast as 85 mph and there are no sign of the shakes at all.
I now firmly believe that with all the changes that I've made to my SC that I need a custom toe-in setting. My next step is to rotate the tires to get some evenly worn rubber up front. I'll continue to drive and. I'll be watching and feeling my tires. I'l be looking for signs of continuing insufficient toe-in or perhaps excessive toe-in. I'll make small adjustments until I'm getting perfect tire wear. When I'm fully satisfied with the tire wear I'll go back to the local shop and get a toe-in reading and make a note of it in my owners manual for future alignments.
I hope this helps give some guidance to some of you that have just been living with the problem and unsuccessful in getting rid of it. Once again, my symptoms were a side-to-side shaking of the steering wheel at 65+ mph that would slowly come-and-go. Sometimes butter smooth but other times just awful. During the shaking the steering would feel lighter than otherwise. I didn't have any shaking in my butt or with my hand on the shifter. It was all side-to-side in the steering wheel.
And then, I rubbed my hand over the front tire and felt ridges, often called "feathering" or "sawtooth" of the tread blocks. Not enough to see but they can be felt. In my case the edges of the ridges can be felt as my hand sweeps over the tread toward the center line of the car.
The inner tread was also wearing faster than the rest of the tire. The inner wear is usually attributed to negative camber, and it can be, but when present along with the ridges that I could feel in the thread this is only one thing: Insufficient toe-in.
I've had several alignments, with printouts, so I'm sure that things were close to factory specifications but I have modified the front end with polyurethane bushings so things are stiffer than OEM.
I cranked in a couple of turns of toe-in and went for a test ride: The shakes are gone. Completely gone. I went as fast as 85 mph and there are no sign of the shakes at all.
I now firmly believe that with all the changes that I've made to my SC that I need a custom toe-in setting. My next step is to rotate the tires to get some evenly worn rubber up front. I'll continue to drive and. I'll be watching and feeling my tires. I'l be looking for signs of continuing insufficient toe-in or perhaps excessive toe-in. I'll make small adjustments until I'm getting perfect tire wear. When I'm fully satisfied with the tire wear I'll go back to the local shop and get a toe-in reading and make a note of it in my owners manual for future alignments.
I hope this helps give some guidance to some of you that have just been living with the problem and unsuccessful in getting rid of it. Once again, my symptoms were a side-to-side shaking of the steering wheel at 65+ mph that would slowly come-and-go. Sometimes butter smooth but other times just awful. During the shaking the steering would feel lighter than otherwise. I didn't have any shaking in my butt or with my hand on the shifter. It was all side-to-side in the steering wheel.
10-23-11, 08:45 AM
#21
Bon-what you are suggesting is what I've often thought on both of my SC's with aftermarket oversized rims....
Alignment gets thown off easily due to either weight of the wheels or toe in, offset or whatever changes. Could also be thrown off by serious bumps in the road, RR tracks or normal more intense driving. Could also be thrown off by dead spots in tires, obviously runout, etc. Now to add another complexity to it...bushings!!!
I've tightened my PS rack on other cars before and noticed a difference to your point. You've convinced me that spending the $30-$40 (I won't DIY looks too messy for me!) for new bushings may be a GREAT thing to try.
I've had both tires on both of my SC's have feathering and when I got an alignment it was way off. Add the changes to a drop like I have and you multiply the complexity of the issue.
I'm a big believer that you do get what you pay for with rims, and although less expensive rims MAY be heavier and MAY not fit as well as JDM rims, all the people buying them can't be wobbling/shaking on every set or they wouldn't sell! I don't hear about shaking from G35/G37 owners, 350/370Z, Mustang owners, etc. Same bolt patterns as us too. Those guys definitely do aftermarket rims much more than we do.
Recently I had discount tire measure runout, look at the treadwear of my two year old Yokohama tires with less than 3k miles on them and they replaced one of my rear tires at no charge. I immediately noticed a different in the shakes...which was strange because I thought my rear wheels would have no bearing on the shakes??? The guys at discount tire basically said to me that they see a ton of high end cars with aftermarket rims and people live with the harsher ride, the wobbles/shakes and just realize that you have to "pay to play". They did confirm (to Liquid SC's point) notion that higher end JDM wheels do seem to fit better and there is no need for hub centric rings, etc.
Could the rings get dust/dirt/particles in between them and the wheel over time and cause the wheels to wobble? SURE...man, add this to the list too!!! LOL great idea to check this, Bon!
I too have thought about bushings but on a 2005 with 39k miles both dealer and DT said they were fine and this was highly unlikely. After reading your posts and the GS link above....it may be worth the money to try???
I am about to add a regulary scheduled alignment to my car's yearly maintenance due to the fact that I have a drop and aftermarket wheels. I firmly believe that what you said above about toe in absolutely happens....and I firmly believe that it changes over time. Not sure if it's because the bolts are not torqued enough or they slip or just aftermarket wheels or bumps, RR tracks or whatever cause it to do this. In my case it could be a multitude of things. I'm curious for you Bon to see if it stays long term fixed.
Alignment gets thown off easily due to either weight of the wheels or toe in, offset or whatever changes. Could also be thrown off by serious bumps in the road, RR tracks or normal more intense driving. Could also be thrown off by dead spots in tires, obviously runout, etc. Now to add another complexity to it...bushings!!!
I've tightened my PS rack on other cars before and noticed a difference to your point. You've convinced me that spending the $30-$40 (I won't DIY looks too messy for me!) for new bushings may be a GREAT thing to try.
I've had both tires on both of my SC's have feathering and when I got an alignment it was way off. Add the changes to a drop like I have and you multiply the complexity of the issue.
I'm a big believer that you do get what you pay for with rims, and although less expensive rims MAY be heavier and MAY not fit as well as JDM rims, all the people buying them can't be wobbling/shaking on every set or they wouldn't sell! I don't hear about shaking from G35/G37 owners, 350/370Z, Mustang owners, etc. Same bolt patterns as us too. Those guys definitely do aftermarket rims much more than we do.
Recently I had discount tire measure runout, look at the treadwear of my two year old Yokohama tires with less than 3k miles on them and they replaced one of my rear tires at no charge. I immediately noticed a different in the shakes...which was strange because I thought my rear wheels would have no bearing on the shakes??? The guys at discount tire basically said to me that they see a ton of high end cars with aftermarket rims and people live with the harsher ride, the wobbles/shakes and just realize that you have to "pay to play". They did confirm (to Liquid SC's point) notion that higher end JDM wheels do seem to fit better and there is no need for hub centric rings, etc.
Could the rings get dust/dirt/particles in between them and the wheel over time and cause the wheels to wobble? SURE...man, add this to the list too!!! LOL great idea to check this, Bon!
I too have thought about bushings but on a 2005 with 39k miles both dealer and DT said they were fine and this was highly unlikely. After reading your posts and the GS link above....it may be worth the money to try???
I am about to add a regulary scheduled alignment to my car's yearly maintenance due to the fact that I have a drop and aftermarket wheels. I firmly believe that what you said above about toe in absolutely happens....and I firmly believe that it changes over time. Not sure if it's because the bolts are not torqued enough or they slip or just aftermarket wheels or bumps, RR tracks or whatever cause it to do this. In my case it could be a multitude of things. I'm curious for you Bon to see if it stays long term fixed.
10-23-11, 04:26 PM
#22
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Ultimately I think that you are best served by learning to "read" your tire wear patterns so you can guide your service technician. If you have the shakes, balance issues, or any alignment issues these problems will take it out on your tires. It will leave marks. If these wear patterns are correctly interpreted they will lead you to your problem(s).
Or, of course, you have to look hard to find a technician that can - and will - do all this for you. Unless you tell them otherwise a technician is duty-bound to set the alignments by-the-book.
However, if you tell them to "stand the tires up" or in other words "minimize the negative camber" then they can do it. This will minimize the inner tire wear. Likewise, if you tell them to check the front tire wear and add in more toe-in, if necessary, then they are free to do that as well. You don't have to be the one doing the work but it sure helps to work closely with your technician and give them the liberty to make adjustments that may be out of the manufacturers specifications when necessary.
Or, of course, you have to look hard to find a technician that can - and will - do all this for you. Unless you tell them otherwise a technician is duty-bound to set the alignments by-the-book.
However, if you tell them to "stand the tires up" or in other words "minimize the negative camber" then they can do it. This will minimize the inner tire wear. Likewise, if you tell them to check the front tire wear and add in more toe-in, if necessary, then they are free to do that as well. You don't have to be the one doing the work but it sure helps to work closely with your technician and give them the liberty to make adjustments that may be out of the manufacturers specifications when necessary.
10-23-11, 07:31 PM
#23
+1 on "stand the tires up" on my 02 SC I never did this, but still added the 20" wheels and never did a drop so my camber was all jacked up I'm sure. At about 5k miles on the car, I had major inner wear and I couldn't believe it!
On my current SC I did adjust the camber right away after adding wheels and again after dropping. Even then, I had perhaps done it too much because I had some feathering and got a tire replaced at no charge by DT.
On my current SC I did adjust the camber right away after adding wheels and again after dropping. Even then, I had perhaps done it too much because I had some feathering and got a tire replaced at no charge by DT.
10-24-11, 09:56 AM
#24
I've recently had an alignment guru tell me that cupping on the fronts when all the front suspension parts are tight and functioning can also occur when the rear thrust angle is out of specs. Makes sense since with the front tires aiming 'straight ahead' the car is being pushed by the rear tires in a slightly different direction. That plus toe-in issues?
10-24-11, 12:02 PM
#25
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I bought my 2007 brand new and have NEVER totally gotten rid of those shakes. Hope you find something else i can try cuz mine is still under warrenty and they don't feel what I do...
10-24-11, 03:15 PM
#26
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I've recently had an alignment guru tell me that cupping on the fronts when all the front suspension parts are tight and functioning can also occur when the rear thrust angle is out of specs. Makes sense since with the front tires aiming 'straight ahead' the car is being pushed by the rear tires in a slightly different direction. That plus toe-in issues?
Oh, and cupping is not to be confused with feathering. They're two different animals.
10-26-11, 08:17 PM
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my 03 starts the shimmy-shimmy coco bop around 80-82. but completely stops once i wind it out to 180.
just kidding about the 180....i've not pushed it over 120 but at that speed there seems to be plenty of pedal left.
no shimmy under 80...none over 85. wierd.
just kidding about the 180....i've not pushed it over 120 but at that speed there seems to be plenty of pedal left.
no shimmy under 80...none over 85. wierd.
Last edited by elvis1955; 10-27-11 at 05:47 PM. Reason: spelling
10-26-11, 08:38 PM
#28
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I believe that the shimmy point is where your front end becomes toe-neutral. That is, the road forces are pushing back on the front tires. This pushes the suspension into an unstable position that is very likely to oscillate and shimmy. A little more toe-in would be worth a try if you want to defeat this. If you keep going faster then you may reach a toe-out condition that will make steering more responsive than normal to inputs. Race cars can use toe-out to their advantage to enhance steering response.
10-29-11, 01:40 PM
#29
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A brief update. I "read" my front tires with the palm of my hand and, after a weeks driving, they tell me that I have a bit too much toe in. I originally had added 12-points of toe in (6-points on each side) last week. So I dialed out 4-points of toe-in today. This leaves me with 8-points of additional toe-in from the last alignment.
I'll drive for another week or so and do another evaluation of the tire scrub. The good news is that my 65-70 mph shake is still gone with the current settings and the steering feels a bit lighter as well. I'm loving driving my car without the shakes!
I'll drive for another week or so and do another evaluation of the tire scrub. The good news is that my 65-70 mph shake is still gone with the current settings and the steering feels a bit lighter as well. I'm loving driving my car without the shakes!