Reconsidering the Factory Alignment
06-30-15, 08:57 AM
#241
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I have another alignment scheduled for Friday - i will report back.
I researched the tires and the spacers extensively before buying them. Recognizing the change of suspension geometry with spacers (which I hoped I would not notice unless I track the car), I did not stumble upon anyone with this specific issue before.
BTW, the issue is pretty subtle, but I noticed it right away. It may be my sensitivity to the "feel". I think another way to describe the sensation is as if I am getting hit by a strong crosswind at speed sometimes.
I researched the tires and the spacers extensively before buying them. Recognizing the change of suspension geometry with spacers (which I hoped I would not notice unless I track the car), I did not stumble upon anyone with this specific issue before.
BTW, the issue is pretty subtle, but I noticed it right away. It may be my sensitivity to the "feel". I think another way to describe the sensation is as if I am getting hit by a strong crosswind at speed sometimes.
06-30-15, 11:15 AM
#242
Lexus Fanatic
It's a compromise and I'm sure everyone realize this. I don't think trying to extend the life on a set of $1200 tires is unreasonable, especially if you aren't taking the car to the track regularly. Also, zero toe is within spec. Spacers or even possibility the Contis are probably the issue Vervish is describing. I recently had mine done after installing the FIGS LCA bushings and just yesterday drove 150 miles averaging 80-90 mph on some PSS with around 15k on them. The car felt fine.
I have another alignment scheduled for Friday - i will report back.
I researched the tires and the spacers extensively before buying them. Recognizing the change of suspension geometry with spacers (which I hoped I would not notice unless I track the car), I did not stumble upon anyone with this specific issue before.
BTW, the issue is pretty subtle, but I noticed it right away. It may be my sensitivity to the "feel". I think another way to describe the sensation is as if I am getting hit by a strong crosswind at speed sometimes.
I researched the tires and the spacers extensively before buying them. Recognizing the change of suspension geometry with spacers (which I hoped I would not notice unless I track the car), I did not stumble upon anyone with this specific issue before.
BTW, the issue is pretty subtle, but I noticed it right away. It may be my sensitivity to the "feel". I think another way to describe the sensation is as if I am getting hit by a strong crosswind at speed sometimes.
06-30-15, 11:41 AM
#243
Vervish, your crosswind analogy is exactly what I felt on my car. I suspect my toe was not as bad as yours because I never felt it until I was well into the mid 100's.
I tired some spacers a while back with the stock wheels and the steering wheel would vibrate around a 100 so I removed them the same day. Looked good but they were obviously junk! They were H&R spacers which were supposed to be "good".
I tired some spacers a while back with the stock wheels and the steering wheel would vibrate around a 100 so I removed them the same day. Looked good but they were obviously junk! They were H&R spacers which were supposed to be "good".
06-30-15, 11:56 AM
#244
Thanks - my spacers feel fine at speed, no vibrations.
I had an alignment recently - they set it to exactly 0 toe up front. If the new alignment (back to stock specs) does not help, I will remove the spacers to see if there is a difference.
I am thinking (hoping) that static zero toe up front may be causing toe in/out under acceleration/braking because of the flex in the bushings. By dialing in some toe out I think it will help stability..but clearly I am not suspension geometry expert. Fingers crossed.
I had an alignment recently - they set it to exactly 0 toe up front. If the new alignment (back to stock specs) does not help, I will remove the spacers to see if there is a difference.
I am thinking (hoping) that static zero toe up front may be causing toe in/out under acceleration/braking because of the flex in the bushings. By dialing in some toe out I think it will help stability..but clearly I am not suspension geometry expert. Fingers crossed.
06-30-15, 04:31 PM
#245
Tech Info Resource
Thread Starter
iTrader: (2)
Lexus set the alignment for performance. People shouldn't expect the car to feel the same when you start messing with alignment specs . You guys are driving a performance car and trying to eek out more tire life by messing with something as critical as alignment . I mentioned the specs to my tech at my last service and he said it would be to the detriment of the handling feel . Members kind of dismissed the info when I brought it up last time but from the similar complaints from the members with and without the spacers is feeling the same thing it seems like it could the specs and not the spacers .
Lobux , all due respect , but you are always mentioning the virtues of factory design and how sensitive and linked it all is but yet you are tweaking something as critical as alignment , knowing that it effects turn in . I am surprised to see this based on your comments on many other topics . You haven't done a track day in a while so I would ask , would you run these specs for a track day ? Thanks
I have gone through 2 sets os tires in 16k miles . Lol I am amazed people are trying to get 25k out of a set of tires and complaining about wear
Lobux , all due respect , but you are always mentioning the virtues of factory design and how sensitive and linked it all is but yet you are tweaking something as critical as alignment , knowing that it effects turn in . I am surprised to see this based on your comments on many other topics . You haven't done a track day in a while so I would ask , would you run these specs for a track day ? Thanks
I have gone through 2 sets os tires in 16k miles . Lol I am amazed people are trying to get 25k out of a set of tires and complaining about wear
Maybe you just don't understand this stuff, but there is a range of acceptable adjustment, and the numbers I am suggesting are WELL within the range of acceptable. I'm not suggesting anyone adjust their suspension to numbers out of the range of acceptable. I am telling anyone who cares about tire life and braking performance that setting the toe to 0.04 degrees out on each side makes the car wear tires more evenly which also enhances braking because when the tires are toed out too much or toed in too much, you lose contact patch and overheat part of the tire which causes the uneven wear.
If you don't want to learn, don't chastise those who have. Otherwise, I would hand out medical advice to anyone who would listen too.
06-30-15, 04:34 PM
#246
Tech Info Resource
Thread Starter
iTrader: (2)
Thanks - my spacers feel fine at speed, no vibrations.
I had an alignment recently - they set it to exactly 0 toe up front. If the new alignment (back to stock specs) does not help, I will remove the spacers to see if there is a difference.
I am thinking (hoping) that static zero toe up front may be causing toe in/out under acceleration/braking because of the flex in the bushings. By dialing in some toe out I think it will help stability..but clearly I am not suspension geometry expert. Fingers crossed.
I had an alignment recently - they set it to exactly 0 toe up front. If the new alignment (back to stock specs) does not help, I will remove the spacers to see if there is a difference.
I am thinking (hoping) that static zero toe up front may be causing toe in/out under acceleration/braking because of the flex in the bushings. By dialing in some toe out I think it will help stability..but clearly I am not suspension geometry expert. Fingers crossed.
Has no one else here done any chassis tuning? No one else worked on sprint cars or dirt track cars?
06-30-15, 08:20 PM
#248
Lexus Fanatic
Any time someone says "all due respect" they''re following with an insult.
Maybe you just don't understand this stuff, but there is a range of acceptable adjustment, and the numbers I am suggesting are WELL within the range of acceptable. I'm not suggesting anyone adjust their suspension to numbers out of the range of acceptable. I am telling anyone who cares about tire life and braking performance that setting the toe to 0.04 degrees out on each side makes the car wear tires more evenly which also enhances braking because when the tires are toed out too much or toed in too much, you lose contact patch and overheat part of the tire which causes the uneven wear.
If you don't want to learn, don't chastise those who have. Otherwise, I would hand out medical advice to anyone who would listen too.
Maybe you just don't understand this stuff, but there is a range of acceptable adjustment, and the numbers I am suggesting are WELL within the range of acceptable. I'm not suggesting anyone adjust their suspension to numbers out of the range of acceptable. I am telling anyone who cares about tire life and braking performance that setting the toe to 0.04 degrees out on each side makes the car wear tires more evenly which also enhances braking because when the tires are toed out too much or toed in too much, you lose contact patch and overheat part of the tire which causes the uneven wear.
If you don't want to learn, don't chastise those who have. Otherwise, I would hand out medical advice to anyone who would listen too.
I drive rural highways ( very very high speeds every single day ), and do track days more than anyone I have seen on this forum so I am not wiling to compromise any performance or especially high speed stability. Just trying to get more info.
Last edited by I8ABMR; 06-30-15 at 09:47 PM.
07-01-15, 09:09 AM
#249
Tech Info Resource
Thread Starter
iTrader: (2)
Toe - in or out - decreases straight line stability. Static toe and dynamic toe are different. I might set static toe to zero, but once the car starts moving and the bushings get loaded, it may toe in or out or both depending on what is happening. This is why the rear LCA bushing is such a big deal. It severely toes out the front under braking.
If we had solid bearings (like a real racecar) then static and dynamic chassis concerns are a whole lot less. With rubber bushings to absorb NVH and make the car more comfortable on the street, we have considerable change between sitting at a stop light and braking, turning, or accelerating.
This is why it has been an adventure to find a setting optimized for my driving. I'm happy to share it with others simply because it makes the car pretty stable and evens out the tire wear issue.
The factory numbers allow for toe-in and toe-out. The green lights on the alignment rack are pretty indiscriminate, but as long as the lights are green, you are within factory specs. I choose a number within the range to provide the best balance between braking, turning, and tire wear. Keep in mind, if you are wearing out the inside (or outside) edges of your tires, you are not getting the full traction available from the tire in service.
Autocrossers use a lot of toe out to "help" the car turn, but if you look at the information provided by a national championship winner, you'll find there's a whole lot more to it than just toe out.
If we had solid bearings (like a real racecar) then static and dynamic chassis concerns are a whole lot less. With rubber bushings to absorb NVH and make the car more comfortable on the street, we have considerable change between sitting at a stop light and braking, turning, or accelerating.
This is why it has been an adventure to find a setting optimized for my driving. I'm happy to share it with others simply because it makes the car pretty stable and evens out the tire wear issue.
The factory numbers allow for toe-in and toe-out. The green lights on the alignment rack are pretty indiscriminate, but as long as the lights are green, you are within factory specs. I choose a number within the range to provide the best balance between braking, turning, and tire wear. Keep in mind, if you are wearing out the inside (or outside) edges of your tires, you are not getting the full traction available from the tire in service.
Autocrossers use a lot of toe out to "help" the car turn, but if you look at the information provided by a national championship winner, you'll find there's a whole lot more to it than just toe out.
07-01-15, 10:19 AM
#250
Lexus Fanatic
Toe - in or out - decreases straight line stability. Static toe and dynamic toe are different. I might set static toe to zero, but once the car starts moving and the bushings get loaded, it may toe in or out or both depending on what is happening. This is why the rear LCA bushing is such a big deal. It severely toes out the front under braking.
If we had solid bearings (like a real racecar) then static and dynamic chassis concerns are a whole lot less. With rubber bushings to absorb NVH and make the car more comfortable on the street, we have considerable change between sitting at a stop light and braking, turning, or accelerating.
This is why it has been an adventure to find a setting optimized for my driving. I'm happy to share it with others simply because it makes the car pretty stable and evens out the tire wear issue.
The factory numbers allow for toe-in and toe-out. The green lights on the alignment rack are pretty indiscriminate, but as long as the lights are green, you are within factory specs. I choose a number within the range to provide the best balance between braking, turning, and tire wear. Keep in mind, if you are wearing out the inside (or outside) edges of your tires, you are not getting the full traction available from the tire in service.
Autocrossers use a lot of toe out to "help" the car turn, but if you look at the information provided by a national championship winner, you'll find there's a whole lot more to it than just toe out.
If we had solid bearings (like a real racecar) then static and dynamic chassis concerns are a whole lot less. With rubber bushings to absorb NVH and make the car more comfortable on the street, we have considerable change between sitting at a stop light and braking, turning, or accelerating.
This is why it has been an adventure to find a setting optimized for my driving. I'm happy to share it with others simply because it makes the car pretty stable and evens out the tire wear issue.
The factory numbers allow for toe-in and toe-out. The green lights on the alignment rack are pretty indiscriminate, but as long as the lights are green, you are within factory specs. I choose a number within the range to provide the best balance between braking, turning, and tire wear. Keep in mind, if you are wearing out the inside (or outside) edges of your tires, you are not getting the full traction available from the tire in service.
Autocrossers use a lot of toe out to "help" the car turn, but if you look at the information provided by a national championship winner, you'll find there's a whole lot more to it than just toe out.
07-01-15, 11:22 AM
#251
So a couple of things to note - the tie rods will change toe approximately 1/8" per full revolution on one side. If you want your center steer point to remain straight ahead, you'll need to make adjustments to both sides. If you adjust both sides out one full turn on each side, you'll have +1/4" toe out. That's a LOT for a street driven car. A half turn on each side would yield 1/8", and a quarter turn on each side would yield 1/16".
Should I be turning clockwise or counterclockwise turns to get toe out?
Last edited by Vervish; 07-01-15 at 11:39 AM.
07-01-15, 11:41 AM
#252
Sponsor
iTrader: (1)
The problem with the suspension is the dynamic alignment changes that occur during cornering and braking. That is what our Ultimate Steering Response Bushing (USRS) was meant to address. Its quite amazing that Lexus carried over the same bushing design from the IS to the ISF, because even if they used a stiffer rubber, the higher cornering capability and weight of the ISF warrants a completely revised LCA bushing design.
One of the problems with adjusting the ISF suspension for slight toe out is that under braking, the toe out tends to increase further, and this is the culprit for the excessive inner tire wear that many are seeing. When pushing your car hard on the street or track with sticky tires, the dynamic toe changes up front actually cause the car to feel somewhat unstable in high speed braking zones, not to mention other effects on handling.
Here is a little graphical representation of what happens under braking:
One of the problems with adjusting the ISF suspension for slight toe out is that under braking, the toe out tends to increase further, and this is the culprit for the excessive inner tire wear that many are seeing. When pushing your car hard on the street or track with sticky tires, the dynamic toe changes up front actually cause the car to feel somewhat unstable in high speed braking zones, not to mention other effects on handling.
Here is a little graphical representation of what happens under braking:
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Last edited by RRRacing; 07-01-15 at 11:54 AM. Reason: spelling correction
07-01-15, 11:44 AM
#253
Tech Info Resource
Thread Starter
iTrader: (2)
I am thinking of adjusting the toe myself (instead of at dealer) since my alignment with zero toe is about 2 weeks young. Plan is to set it to 1/16th toe out as you describe (1/4 turn) and see if I notice a difference.
Should I be turning clockwise or counterclockwise turns to get toe out?
Should I be turning clockwise or counterclockwise turns to get toe out?
07-01-15, 12:05 PM
#255
Tech Info Resource
Thread Starter
iTrader: (2)
The problem with the suspension is the dynamic alignment changes that occur during cornering and braking. That is what our Ultimate Steering Response Bushing (USRS) was meant to address. Its quite amazing that Lexus carried over the same bushing design from the IS to the ISF, because even if they used a stiffer rubber, the higher cornering capability and weight of the ISF warrants a completely revised LCA bushing design.
One of the problems with adjusting the ISF suspension for slight toe out is that under braking, the toe out tends to increase further, and this is the culprit for the excessive inner tire wear that many are seeing. When pushing your car hard on the street or track with sticky tires, the dynamic toe changes up front actually cause the car to feel somewhat unstable in high speed braking zones, not to mention other effects on handling.
Here is a little graphical representation of what happens under braking:
One of the problems with adjusting the ISF suspension for slight toe out is that under braking, the toe out tends to increase further, and this is the culprit for the excessive inner tire wear that many are seeing. When pushing your car hard on the street or track with sticky tires, the dynamic toe changes up front actually cause the car to feel somewhat unstable in high speed braking zones, not to mention other effects on handling.
Here is a little graphical representation of what happens under braking:
If it weren't for NVH, we'd be way better off with spherical bearings and get rid of all the rubber junk.