Toe "Tendency"

[Tony]

First absorb this image....

 

 

Very dynamic. From this image it's obvious the Toe position is subject to change since the compressive compensator's between the cars parallelograms are not conveniently set a right angles. Design areas like steering arm and control arm radii are well researched.... Equally the coil/damper reaction ranges within the kinematics fall within the calibration...Add some pneumatic rolling resistance and (shake) then you have a field called "Toe tendency".

 

So what! Well most domestic complaints regarding front tyre wear is due to Toe and a static measurement will acquire the actual position but not the "tendency" making any static corrections redundant.

 

So? It is possible to measure this tendency if the front wheels are placed on full floating radius plates?

 

Radius plates? These are platforms sandwich with ball-bearings allowing the car to literally float removing resistance.

 

Results On the plates (domestically) you can now read a static toe, compress the suspension and read one area of the dynamic toe then relax the suspension and read the other end of the dynamic toe, this is the actual toe tendency range.

 

Conclusion? For simplicity lets assume the static Toe position is 0' add suspension compression it moves to -15', relax and lift it moves to +5'. So in actual fact this car has a Toe "Tendency" of -10'. Way off the initial static 0 measured.

 

Toe tendency is never observed but a real phonominom if realized domestically. Motorsports aggressively address this area since it's vital to the chassis compliance, yet it's conveiniently ignored corporately for you and me!

 

Next time you have the Alignment measured ask what the "tendency" is!

[Tony]

Did some "awareness" tests on various company's over the last few days (including STS) and non of them knew of the condition "Toe tenancy".... Rather worrying really. Once explained all understood the logistics but had never observed the operation. Still we know better wim

[Sam@TDi]

Remember last year when we were discussing what exactly "kinematic toe" really ment? .... well this is pretty much it

[Tony]

Remember last year when we were discussing what exactly "kinematic toe" really ment? .... well this is pretty much it

Are we talking the Porsche? thing is with that the scale was longitudinal? Also i was reading in the Civic forums the type R has habitual inner front tyre wear.... and i recall you saying your car has "bump on "toe out".... is that correct or was it "bump off" toe out?

[Sam@TDi]

Yeah as standard the EP3 Civic is very toe-in with the wheels in droop (the car jacked) and toe out as you put the car down, the issue we have with the ep3 is that the track arms are at a pretty acute angle even at standard ride height and get rapidly worse as the car is lowered, with very low ride heights the arm angles get ridiculous and cause a very aggressive toe-out on bump scenario. I found that it gave rise to poor turn in and straight line bump steer.

 

The fix for me was to lower the track rod end so that the steering arm formed a proper Parallelogram with the lower arm. Infact I've gone a bit further and dropped the TRE lower still to give a gentle toe-in on bump scenario, the result has been razor sharp turn in but at the expense of fast corner stability. My choice and certainly keeps me awake on the motorway

[Tony]

Yeah as standard the EP3 Civic is very toe-in with the wheels in droop (the car jacked) and toe out as you put the car down, the issue we have with the ep3 is that the track arms are at a pretty acute angle even at standard ride height and get rapidly worse as the car is lowered, with very low ride heights the arm angles get ridiculous and cause a very aggressive toe-out on bump scenario. I found that it gave rise to poor turn in and straight line bump steer.

 

The fix for me was to lower the track rod end so that the steering arm formed a proper Parallelogram with the lower arm. Infact I've gone a bit further and dropped the TRE lower still to give a gentle toe-in on bump scenario, the result has been razor sharp turn in but at the expense of fast corner stability. My choice and certainly keeps me awake on the motorway

Love to know what engineering was involved in this modification!!!! Obviously the TRE has a tapered male pin with a manufactured length.... curiosity wonders how this parallelogram has been lowered? Also Sam@tdi can you suggest what increments in correction favored the "Better turn in"? ... Static the Civic has a 0 toe, natural positive positioning under torque, normal rolling/braking forces and now positive "bump off".... What static advantage from the modifications are we talking?.. +20'

[Sam@TDi]

To be honest i'd love to use some pull downs and quantify the exact amount of toe on bump i've got but I've never had the time. It's been set up purely by "development driving"

 

My ground breaking design is shown below, sorry about the quality was a 5min MSPaint effort

 

[Tony]

Quote: Sam@tdi

Impressive! What was the gain? i imagine 30mm. Innovative modification...... Love the "grrrrrrrr tight" Beauty here is as you say progressive tested increments to establish the ideal bump radii position.... In the past i used a simple less manufactured option of removing the track rod end from it's "nose down" position and re-fitted it underneath "nose up". Problem was this method was absolute and had no calibration....

[Sam@TDi]

Glad you like it i've dropped the rod end around 50mm

[Tony]

Glad you like it i've dropped the rod end around 50mm

It is very innovative.. reinforced rose joint with flexible calibration available.... I wonder this though are you willing to display the static toe position? just so i can image some dynamics.... A "NO" will not offend, it may result with a cat in space but i would respect your research regardless.

[Sam@TDi]

If you mean the static toe in the rested position it's 0'01... straight ahead at the front

[Tony]

If you mean the static toe in the rested position it's 0'01... straight ahead at the front

So a bump toe out tendency from i assume a proscribed 0 static toe.... To a lower steering radii of 50mm resulting with a positive "bump on" toe tendency, and retaining a static 0 toe position. I'm struggling with that! Sam@tdi what were the toe gains on the "pull downs" before the modification? Reason i ask is the Civic has such a long steering arm then by degrees the parallelogram disparity after lowering should be negligible..... 50mm worth of compensation is a mighty move.

[Sam@TDi]

Yeah I can see what you meen but remember that the rack position and steering arm geometry was disgned for the EP2 1.6 shopping trolley edition, if i remember correctly the type-r model is around 40mm lower from the show room and then in turn i'm running approx 70mm lower that the standard type-r.

I never quanitfied the toe change on bump with my car, but when I was building the Nemesis brit car civic I spent alot of time looking at this and it since turns out it's something that Honda racing legends Barwell motorsport, Mardigras and Syncro motorsport have all had to deal with to improve front end response

[Tony]

Yeah I can see what you meen but remember that the rack position and steering arm geometry was disgned for the EP2 1.6 shopping trolley edition, if i remember correctly the type-r model is around 40mm lower from the show room and then in turn i'm running approx 70mm lower that the standard type-r.

I never quanitfied the toe change on bump with my car, but when I was building the Nemesis brit car civic I spent alot of time looking at this and it since turns out it's something that Honda racing legends Barwell motorsport, Mardigras and Syncro motorsport have all had to deal with to improve front end response

Very interesting. Other than doing some analysis on the Arigo Geo machine i cannot comment. Out of curiosity though do you have any TOOT or Ackerman data your are willing to display?

[Sam@TDi]

Yeah I can see what you meen but remember that the rack position and steering arm geometry was disgned for the EP2 1.6 shopping trolley edition, if i remember correctly the type-r model is around 40mm lower from the show room and then in turn i'm running approx 70mm lower that the standard type-r.

I never quanitfied the toe change on bump with my car, but when I was building the Nemesis brit car civic I spent alot of time looking at this and it since turns out it's something that Honda racing legends Barwell motorsport, Mardigras and Syncro motorsport have all had to deal with to improve front end response

Very interesting. Other than doing some analysis on the Arigo Geo machine i cannot comment. Out of curiosity though do you have any TOOT or Ackerman data your are willing to display?

 

I'd certainly tell you if did but unfortunately I don't. Beleive it or not I don't have regular access to a global alignment machine and my car is pulled apart on a fairly regular basis, so the only new and relevent data I have is from bbt's 8-angle machine

[Tony]

Yeah I can see what you meen but remember that the rack position and steering arm geometry was disgned for the EP2 1.6 shopping trolley edition, if i remember correctly the type-r model is around 40mm lower from the show room and then in turn i'm running approx 70mm lower that the standard type-r.

I never quanitfied the toe change on bump with my car, but when I was building the Nemesis brit car civic I spent alot of time looking at this and it since turns out it's something that Honda racing legends Barwell motorsport, Mardigras and Syncro motorsport have all had to deal with to improve front end response

Very interesting. Other than doing some analysis on the Arigo Geo machine i cannot comment. Out of curiosity though do you have any TOOT or Ackerman data your are willing to display?

 

I'd certainly tell you if did but unfortunately I don't. Beleive it or not I don't have regular access to a global alignment machine and my car is pulled apart on a fairly regular basis, so the only new and relevent data I have is from bbt's 8-angle machine

Shame.... Still that should change in the near future hopefully The machine is able to gather some very useful chassis information

[Roger440]

A 50mm adjustment!!!!! Thats a lot! Like the mod though. I have a similar, though less extreme problem with my old Triumph 2000. Had considered the "turn it upside down" idea, but its as Tony says, has no adjustment.

 

Might have to have a dabble some time. The triumph does suffer from bump steer but there other influencing factors i need to deal with first.

 

Re the kniematic toe we talked about last year, my understanding of it is that it is effectively being used to describe a rear steering tendancy which is built into the design, at least in this application (Porsche 993)

[Tony]

A 50mm adjustment!!!!! Thats a lot! Like the mod though. I have a similar, though less extreme problem with my old Triumph 2000. Had considered the "turn it upside down" idea, but its as Tony says, has no adjustment.

 

Might have to have a dabble some time. The triumph does suffer from bump steer but there other influencing factors i need to deal with first.

 

Re the kniematic toe we talked about last year, my understanding of it is that it is effectively being used to describe a rear steering tendancy which is built into the design, at least in this application (Porsche 993)

The 993 Kinematic tool still bothers me?... It's position is longitudinal, so am i correct in saying the measurement is for "drive axel" longitudinal displacement allowing independent adjustments per axel.. ensuring each wheel is correctly placed under load?

[Roger440]

A 50mm adjustment!!!!! Thats a lot! Like the mod though. I have a similar, though less extreme problem with my old Triumph 2000. Had considered the "turn it upside down" idea, but its as Tony says, has no adjustment.

 

Might have to have a dabble some time. The triumph does suffer from bump steer but there other influencing factors i need to deal with first.

 

Re the kniematic toe we talked about last year, my understanding of it is that it is effectively being used to describe a rear steering tendancy which is built into the design, at least in this application (Porsche 993)

The 993 Kinematic tool still bothers me?... It's position is longitudinal, so am i correct in saying the measurement is for "drive axel" longitudinal displacement allowing independent adjustments per axel.. ensuring each wheel is correctly placed under load?

 

Can't be quite sure as yet. When i next have one in, i will take pictures and post. Havn't seen a 993 in the workshop for a while

 

Once we can see the suspension on the car, im sure it will become more obvious.

[Tony]

A 50mm adjustment!!!!! Thats a lot! Like the mod though. I have a similar, though less extreme problem with my old Triumph 2000. Had considered the "turn it upside down" idea, but its as Tony says, has no adjustment.

 

Might have to have a dabble some time. The triumph does suffer from bump steer but there other influencing factors i need to deal with first.

 

Re the kniematic toe we talked about last year, my understanding of it is that it is effectively being used to describe a rear steering tendancy which is built into the design, at least in this application (Porsche 993)

The 993 Kinematic tool still bothers me?... It's position is longitudinal, so am i correct in saying the measurement is for "drive axel" longitudinal displacement allowing independent adjustments per axel.. ensuring each wheel is correctly placed under load?

 

Can't be quite sure as yet. When i next have one in, i will take pictures and post. Havn't seen a 993 in the workshop for a while

 

Once we can see the suspension on the car, im sure it will become more obvious.

 

Please keep us apprised. It's a very interesting opportunity for us to learn.