Laser Schmaser ?

[IdahoMtnSpyder]

OK guys, I watched the videos. They do answer one question I've had about laser alignment and that is how the rear wheel comes into play. I see now. The rear wheel is the best reference point available to use to establish where the laser beams need to be in order to be parallel to the frame of the Spyder. The front wheel track, i.e. the distance between the laser beams at the wheels, is used to determine how far from each side of the rear wheel the eventual target points need to be left and right. So we start by by securing the handlebar to keep the steering in a fixed position. Then move the Spyder back and forth a bit to relieve any binding in the steering as Lamont mentions in his video.

Looking at my sketch below locate the four targets at distance D1 from the front wheel centers. Then move them left and right until the laser points are on the zero target lines. Measure the distance between the target zero lines. Add F & R and divide by 2. That gives you T, the distance between the laser lines at the axis of the front wheels. From here follow the the procedure shown in the videos.

Laser sketch 001.jpg

As far as camber affecting the accuracy of the track distance by using laser points straight down, that is correct, strictly speaking. I suspect real practice has shown that that error is inconsequential in the overall scheme of the alignment process. In fact it's probably less than the errors caused by using ordinary tape measures handled by human hands! I'm sure ROLO wouldn't use lasers pointing straight down if it caused a significant error.

[IdahoMtnSpyder]

Let me share why I'm willing to quibble with the accepted procedure for measuring track width.

I worked for Uncle Sam for over 22 years in monitoring contractors work processes and practices. During that time I came up with the slogan QAQAQA, "The Questioning Approach of Quality Assurance leads to the Quintessential Answer". What I learned is that oftentimes experts and professionals get locked into a certain way of performing a job and did not willingly look for alternative methods. I would often question why they did something in a particular fashion. The end result was one of three results. 1) I learned more about a particular process, or 2) the person who was doing the work would look at or for a different way and end up with an improved outcome, or 3) in defending the process the correctness of the process was verified.

So what I'm saying with respect to measuring the tracking width is not that the usual method is wrong, but there is an alternative way. Better? Maybe, maybe not. My suggested method eliminates the potential error caused by camber and the need to move the bike out of the way to take the measurement. It possibly introduces some error from additional measurements and moving the targets.

[merlot]

"This video by Shawn Smoak ido not see him measure track width. Possibly his video format omitted it, but if an alignment can be done without learning what true zero is, I would enjoy hearing how that is possible"


my understanding of true zero is handlebar position when bike is underway.....this explains why he dosent need track width(he knew the bars were straight)
if the bars point to the right,say,then you can adjust them back to centre by adjusting both wheels into the direction of the bars,until bars are straight when underway,then shoot front and back to set the toe,adjusting both track rods the same amount

this takes away the need for bringing the rear wheel into the equation(or making grids or finding the track width)...its only needed to set handlebar position(and greatly simplifies the alignment process).....but only if you can ride the bike,or ask the owner if bars are straight

of course,if the bars are already straight,when the bike is underway, then you only need to shoot front and back to get the correct toe....no need to lock down the handlebars,as you will adjust both tie rods an equal amount

there is only one adjustment for alignment purposes(tie rods)so how many things do we expect to influence?
ANSWER.....2 toe in/out and handlebar position when underway

russ

[lindsayw148]

OK, I’m ‘the aussie guy’ and the reason why I specify aiming the lasers on the ‘pie-plates’ (standoffs) to the rear while measuring the width at the front wheels is that the Spyder has a small amount of negative camber. It’s only 3mm (about 1/8”) on average, and that average is important – in other words, it’s slightly different on every bike, which doesn’t say a lot for assembly accuracy. I use a set-square on the FLAT floor so the laser dot hits the edge of the square-blade to give a ‘true vertical’ measurement, and that is marked on masking tape on the floor. Pointing the laser down to the floor will result in a slightly wider width measurement. You don’t need to roll the bike forward or backward to measure the width – you can slide a tape under the curve of the wheels at the exact point below the rear of the wheel rim, so avoiding any parallax error in measurement. That gives you a fairly accurate width measurement.

Yes, the rear of the ‘box’ is measured outward from the rear-most point of the rear wheel rim, so that DOES assume that the rear wheel is running true. But remember that the ‘box’ is about five time the diameter of the front wheels long, so all the measurements at the back of the bike are multiplied five times – that 1/8” camber ‘spread’ can be clearly measured over that distance. That’s the whole point of using lasers. You read the measurements where they are magnified, not at the front wheels.
Lastly, because the Spyder is rear-wheel-drive, the front wheels tend to spread IN MOTION so that any toe-out is exaggerated, any toe-in is reduced. The amount will depend on the amount of wear and tear in front suspension and steering, but is usually in the order of 0.5mm, so the amount of toe-in (at the wheels) needs to be at least that much! Just watching the laser dots on the targets when someone climbs onto the bike doesn’t show any left-right variation – just up-down variation as the bike squats down.

After dozens of Spyders aligned and NOBODY offering anything except praise, I think that this ‘imperfect’ system is quite good enough.

[Peter Aawen]

..........
After dozens of Spyders aligned and NOBODY offering anything except praise, I think that this ‘imperfect’ system is quite good enough.

You can spend hours getting lost in the minutiae of an increasingly technical search for absolute alignment accuracy & end up chasing your own tail down the hole, but when push comes to shove, the blunt truth of the matter is that this 'imperfect' system is somewhat more than being 'just adequate' for the Spyder's front end & steering! And anyone who's enjoyed the results will probably agree that in a significant majority of cases, this 'imperfect' system results in WAAAAYYYYY better rideability & handling/behaviour than whatever method gets used by the factory &/or many dealers!

[PMK]

OK, I’m ‘the aussie guy’ and the reason why I specify aiming the lasers on the ‘pie-plates’ (standoffs) to the rear while measuring the width at the front wheels is that the Spyder has a small amount of negative camber. It’s only 3mm (about 1/8”) on average, and that average is important – in other words, it’s slightly different on every bike, which doesn’t say a lot for assembly accuracy. I use a set-square on the FLAT floor so the laser dot hits the edge of the square-blade to give a ‘true vertical’ measurement, and that is marked on masking tape on the floor. Pointing the laser down to the floor will result in a slightly wider width measurement. You don’t need to roll the bike forward or backward to measure the width – you can slide a tape under the curve of the wheels at the exact point below the rear of the wheel rim, so avoiding any parallax error in measurement. That gives you a fairly accurate width measurement.

Yes, the rear of the ‘box’ is measured outward from the rear-most point of the rear wheel rim, so that DOES assume that the rear wheel is running true. But remember that the ‘box’ is about five time the diameter of the front wheels long, so all the measurements at the back of the bike are multiplied five times – that 1/8” camber ‘spread’ can be clearly measured over that distance. That’s the whole point of using lasers. You read the measurements where they are magnified, not at the front wheels.
Lastly, because the Spyder is rear-wheel-drive, the front wheels tend to spread IN MOTION so that any toe-out is exaggerated, any toe-in is reduced. The amount will depend on the amount of wear and tear in front suspension and steering, but is usually in the order of 0.5mm, so the amount of toe-in (at the wheels) needs to be at least that much! Just watching the laser dots on the targets when someone climbs onto the bike doesn’t show any left-right variation – just up-down variation as the bike squats down.

After dozens of Spyders aligned and NOBODY offering anything except praise, I think that this ‘imperfect’ system is quite good enough.

Thank you for posting to this topic.
Right away, I am the person that questioned your method off negating camber effect, by your method of using the square and projecting to the floor.

To keep my questions simple, your projected points to the square and to the floor, they are the basis or datum for rear targets.

If a Spyder has incorrect incoming toe, or worse incorrect and different side to side, doesn’t the dots on the floor become in error, and thereafter, places the targets at the back incorrectly being based off the incorrect incoming toe?

If incorrect incoming toe has no effect on these reference points and the rear target placement, can you explain why?

I understand that a camber setting other than 0.0* will have an effect.

Considering the same scenario as earlier, incoming toe is incorrect, possibly incorrect and differing from each side, in my thinking the likelihood of gross camber error in degrees seems small compared to toe errors, if measured in degrees, and because of this measuring with laser pointed downward seems more accurate. Am I incorrect and if so, can you explain why?

Thanks

[PMK]

You can spend hours getting lost in the minutiae of an increasingly technical search for absolute alignment accuracy & end up chasing your own tail down the hole, but when push comes to shove, the blunt truth of the matter is that this 'imperfect' system is somewhat more than being 'just adequate' for the Spyder's front end & steering! And anyone who's enjoyed the results will probably agree that in a significant majority of cases, this 'imperfect' system results in WAAAAYYYYY better rideability & handling/behaviour than whatever method gets used by the factory &/or many dealers!

Without any doubt, improving upon an oem alignment using almost any method makes a huge gain in handling.

Currently our Spyder has been aligned via using toe sticks. And oddly, the toe sticks have helped resolve incorrectly done laser alignments on other Spyders.

I truly hope Lindsay is not offended by my curiosity, if anything he has done a nice service for Australian Spyder owners.

[jcthorne]

I will add another wrinkle in this. The Rolo system has changed a bit over the years with regard to camber. The original system did indeed 'assume' zero camber and it was ignored for track width measurement. It was generally 'close enough' for most spyders. A few were off and were caught at the back check measurement front to rear and adjustment made. Experience has shown that most Spyders with any significant camber have other issues that an alignment cannot fix. Now the change came in with the Slingshot. It does have camber and the units are all over the place. It became necessary to measure camber using ( I use a digital angle sensor to make it quick and easy). Track measurement is adjusted for measured camber angles in the worksheet and the alignment proceeds normally from there. It became obvious that using the same procedure for Spyders negates the errors that were showing up and revised settings to correct. IE with the camber angle measurement, the alignment comes out dead on and cross checked first time through...every time.

When the Rykers came out and tooling for those became available from Rolo, we see the same camber angle variances that the Slingshots have. Perhaps a bit less erratic but not as close to true zero as most new Spyders. The camber angle measurement as part of alignment again corrects for this. The camber is not adjustable on any of these but can be taken into account for the other measurements and calculations for corrections. We now measure camber on every alignment, in the end it saves time due to zero corrections at cross check.

The Rolo system is only as good as the tech doing the alignment. Its only measurement tools with instructions on how to use. Buying the tools does not make alignment experts.

[IdahoMtnSpyder]

It became obvious that using the same procedure for Spyders negates the errors that were showing up and revised settings to correct. IE with the camber angle measurement, the alignment comes out dead on and cross checked first time through...every time.

We now measure camber on every alignment, in the end it saves time due to zero corrections at cross check.

That certainly dispels the thought that error caused by ignoring camber is not significant!

[IdahoMtnSpyder]

I use a set-square on the FLAT floor so the laser dot hits the edge of the square-blade to give a ‘true vertical’ measurement, and that is marked on masking tape on the floor.

After dozens of Spyders aligned and NOBODY offering anything except praise, I think that this ‘imperfect’ system is quite good enough.

But your method can be influenced by existing toe-in, right? Yes, you do get a point that is not affected by camber, but you're trading that for an effect caused by toe-in since the square is a few inches in front of the wheel axis.

The ideal laser would be one that can be adjusted to be level and plumb in all three axes, keep the x y z origin point of the beam rotation stationary, and keep the horizontal beam perpendicular to the wheel axis.

Why do you choose to not also project the laser to a pair of targets an equal distance in front of the wheels like the ROLO? Doing so would give you twice the measurement you get with the rear projection only.

The key phrase in your comment is "good enough"!

[IdahoMtnSpyder]

of course,if the bars are already straight,when the bike is underway, then you only need to shoot front and back to get the correct toe....no need to lock down the handlebars,as you will adjust both tie rods an equal amount

Hey Russ, it's good to see you're still around!

In reality though, how often are you going to find that the bike tracks straight ahead when the handlebars are in the center position? I believe the main reason for locking the handlebars in place is to prevent inadvertent movement of them from complicating the adjustment process.

After thinking about it some more I still contend toe-in can be correctly set without knowing what the track width is. What you have to end up with is both beams being an equal distance from the rear wheel when the process is finished. Once you know what the beam spread is at the front and the rear you can adjust the rear targets to set the distance between them to be the correct toe-in distance apart when compared to the front, which I think Lamont says is about 1 1/4" difference front target vs rear target? Then you move both targets sideways the same amount until they are an equal distance from the rear wheel.

[lindsayw148]

The key phrase in your comment is "good enough"!

Yes, it is. I have seen Spyders with NO camber on one side and DOUBLE camber on the other, so welding the frame (with its FIXED camber) must be fairly inaccurate, plus the five-times magnification effect solves most of the other problems. Even if the front wheel width measurement is out by the amount of the incoming toe-in/toe-out, that’s a VERY SMALL error, and the targets are placed to magnify that. Certainly it’s true that I have seen bikes with alignment so bad that the laser dot was right off the target (instead of within 20mm of center) but they were usually bikes with pronounced crabbing – handlebar was way off center – and re-measuring the front wheel width in those cases gave me a figure only a couple of mm different. Not enough to make a significant difference.

The enemy is VERY SLIGHT toe-out – that’s what causes the skittery, wandering steering as the wheels encounter bumps and irregularities on the road, causing one tyre or the other to carry more steering load briefly, spearing the bike off in whatever direction it’s pointing, until the other tyre hits the ground and changes that equation. All roads have camber, so the ‘downhill’ wheel (for me that’s the left one – for you it’s the right one), carries slightly more of the load, so it’s the one that usually shows the most tyre scrubbing effect from poor alignment.

[Jetfixer]

"This video by Shawn Smoak ido not see him measure track width. Possibly his video format omitted it, but if an alignment can be done without learning what true zero is, I would enjoy hearing how that is possible"


my understanding of true zero is handlebar position when bike is underway.....this explains why he dosent need track width(he knew the bars were straight)
if the bars point to the right,say,then you can adjust them back to centre by adjusting both wheels into the direction of the bars,until bars are straight when underway,then shoot front and back to set the toe,adjusting both track rods the same amount

this takes away the need for bringing the rear wheel into the equation(or making grids or finding the track width)...its only needed to set handlebar position(and greatly simplifies the alignment process).....but only if you can ride the bike,or ask the owner if bars are straight

of course,if the bars are already straight,when the bike is underway, then you only need to shoot front and back to get the correct toe....no need to lock down the handlebars,as you will adjust both tie rods an equal amount

there is only one adjustment for alignment purposes(tie rods)so how many things do we expect to influence?
ANSWER.....2 toe in/out and handlebar position when underway

russ

The point of locking down the handlebars after finding true center, is to zero out the steering angle using BUDS. This accomplishes a couple of things. It tells the DPS system where straight and true steering angle is, relaxes the current draw of the DPS system at true center, and also centers the turn signal cancelling. You want to adjust each front wheels' toe-in with the steering accurately centered. It is amazing how sensitive the DPS system is to handlebar input. The only way to see this is with BUDS.
Here's a partial screen shot of a BUDS DPS page. If you're not truly centered, your angle will always be off, which affects the VSS system, and the DPS system will always be supplying current to try to "center" you.

[merlot]

hi Idaho...yup,cant kill me with a stick

the bars dont need to be straight for the bike to track straight(just needs unworn tyres)

the bars have nothing to do with the tracking of the bike(ignoring shimmy and bump steer and power steering now activated due to offset)

the two front wheels will fall to the same angle about the thrust vector(push from the back wheel)

you can have perfect toe in/out but also have handlebar offset if the left and right tie rods are at different lengths

the best way to check handlebars is to ride the bike.....if the bars are straight,you cant adjust one tie rod differently from the other as you will offset the bars.....but due to the laws of physics(i call it the Plough Effect,im sure there is a correct term for this phenom but im not smart enough to know what it is)the bike will always track straight.....

it wont track straight if the tyres are already worn thru previous poor alignment or there are other mechanical faults evident

this is why i dont bother aligning anything to the back wheel....the bike will decide its own fate once it gets moving and physics take over

if you took a bike straight off the assembly line,however,then i would definately set the handlebars off the back wheel as the Big Boys do...then set the toe

i THINK that shimmy is the two front wheels trying to equalise their angle to the centreline of force(push vector) more noticeable when toe out is present, or zero toe

these are just my thoughts on the subject,as i didnt train at the "college of alignment"
come to think of it,neither did anyone else

russ

[PMK]

Yes, it is. I have seen Spyders with NO camber on one side and DOUBLE camber on the other, so welding the frame (with its FIXED camber) must be fairly inaccurate, plus the five-times magnification effect solves most of the other problems. Even if the front wheel width measurement is out by the amount of the incoming toe-in/toe-out, that’s a VERY SMALL error, and the targets are placed to magnify that. Certainly it’s true that I have seen bikes with alignment so bad that the laser dot was right off the target (instead of within 20mm of center) but they were usually bikes with pronounced crabbing – handlebar was way off center – and re-measuring the front wheel width in those cases gave me a figure only a couple of mm different. Not enough to make a significant difference.

The enemy is VERY SLIGHT toe-out – that’s what causes the skittery, wandering steering as the wheels encounter bumps and irregularities on the road, causing one tyre or the other to carry more steering load briefly, spearing the bike off in whatever direction it’s pointing, until the other tyre hits the ground and changes that equation. All roads have camber, so the ‘downhill’ wheel (for me that’s the left one – for you it’s the right one), carries slightly more of the load, so it’s the one that usually shows the most tyre scrubbing effect from poor alignment.

Simple chassis lean from unequal spring preloads can induce differences in camber.

So, if I understand your words correctly, you deem camber differences, or even simply camber alone, even if equal left and right, is a greater error in establishing the truly square box than incorrect toe setting?

As I understand the instructions, the point projected aft and downward to the floor is the base number of your targets span. From this dimension you have subtracted the width of the rim and divided by two in order to establish the zero points of the targets. Understood and fair enough, provided the incorrect toe setting prior to aligning, is inconsequential to the zero point of targets. Hypothetically, if the Spyder had even toe per side at 15mm per side on the targets, that translates to 3mm or slightly more at the aft edge of the tire. The point you project downward. Saying that, this would induce a 3mm per side error on the each target, 6mm total.

Is this correct?

[lindsayw148]

As I understand the instructions, the point projected aft and downward to the floor is the base number of your targets span. From this dimension you have subtracted the width of the rim and divided by two in order to establish the zero points of the targets. Understood and fair enough, provided the incorrect toe setting prior to aligning, is inconsequential to the zero point of targets. Hypothetically, if the Spyder had even toe per side at 15mm per side on the targets, that translates to 3mm or slightly more at the aft edge of the tire. The point you project downward. Saying that, this would induce a 3mm per side error on the each target, 6mm total.

No, not quite. The main issue is to avoid that camber error, so the laser should NEVER point anywhere except exactly parallel to the floor. When you point it down, it points outward; when you point it up, it points inward. Only a small amount but enough to make a difference because the error gets magnified over that distance. That's why the scale on the targets are at exactly 270mm height above the floor – the same height as the front wheel hubs. They could be a few mm higher or lower without causing a problem (try measuring the error in an extremely flat triangle that long and you'll suffer brain damage) but just keeping that laser beam parallel to the ground is what steps around the camber problem.

PS: (an afterthought from reading your quote again) camber doesn't make any difference to alignment between forward and aft edge of the wheel, so it doesn't affect the center-line of the targets. It's purely a top-bottom lean on the wheel, but pointing the laser up or down DOES make a sideways difference. So the combo of using a square on the floor to get a true vertical reading at the front wheels (not a camber-affected width) and keeping the laser beam parallel to the floor is what keeps it free of camber influence (plus the target scale at the correct height).

[UtahPete]

hi Idaho...yup,cant kill me with a stick

the bars dont need to be straight for the bike to track straight(just needs unworn tyres)

the bars have nothing to do with the tracking of the bike(ignoring shimmy and bump steer and power steering now activated due to offset)

the two front wheels will fall to the same angle about the thrust vector(push from the back wheel)

you can have perfect toe in/out but also have handlebar offset if the left and right tie rods are at different lengths

the best way to check handlebars is to ride the bike.....if the bars are straight,you cant adjust one tie rod differently from the other as you will offset the bars.....but due to the laws of physics(i call it the Plough Effect,im sure there is a correct term for this phenom but im not smart enough to know what it is)the bike will always track straight.....

it wont track straight if the tyres are already worn thru previous poor alignment or there are other mechanical faults evident

this is why i dont bother aligning anything to the back wheel....the bike will decide its own fate once it gets moving and physics take over

if you took a bike straight off the assembly line,however,then i would definately set the handlebars off the back wheel as the Big Boys do...then set the toe

i THINK that shimmy is the two front wheels trying to equalise their angle to the centreline of force(push vector) more noticeable when toe out is present, or zero toe

these are just my thoughts on the subject,as i didnt train at the "college of alignment"
come to think of it,neither did anyone else

russ

Oh, you Devil you!

[merlot]

hi Jetfixer

i agree with everything you say except this:and the DPS system will always be supplying current to try to "center" you

the DPS isnt there to bring the bike back to centre.......its only needed due to the forces required to overcome the bikes physics....ie its unwillingness to change front wheel angle to the push vector

as you know the dps assist increases as you turn the bars more

i dont know when it kicks in but i would be surprised if it were immediately off "centre"

also the bike is dynamic and jumping around a fair bit at centre so no matter how good you set it,it would always be changing its position

good explanation for locking down the bars,and the progression to the end,but it does mean that anyone without Buds cant be doing wheel alignments.......i never really saw the point of zeroing with Buds(i used to have Buds)but i now see the sense of it(you know its zero if you say it is) i work back to front and set zero dynamically

enjoying this topic and always learning
russ

[merlot]

Oh, you Devil you!

[IdahoMtnSpyder]

the DPS isnt there to bring the bike back to centre.......its only needed due to the forces required to overcome the bikes physics....ie its unwillingness to change front wheel angle to the push vector

as you know the dps assist increases as you turn the bars more

Not quite right. The amount of DPS assist is a function of turning torque, not turning angle. The greater the resistance to turning, as measured by twisting of the steering column portion inside the DPS, the greater the assist. The net result is essentially the same since torque and angle are closely related. I don't know for sure but it makes sense to me that a long radius turn at high speed will prompt more assist than a short radius turn at slow speed.

[PMK]

these are just my thoughts on the subject,as i didnt train at the "college of alignment"
come to think of it,neither did anyone else
russ

Pretty Arrogant Statement.

[merlot]

Not quite right. The amount of DPS assist is a function of turning torque, not turning angle. The greater the resistance to turning, as measured by twisting of the steering column portion inside the DPS, the greater the assist. The net result is essentially the same since torque and angle are closely related. I don't know for sure but it makes sense to me that a long radius turn at high speed will prompt more assist than a short radius turn at slow speed.

yeah that makes a lot of sense
so the torque required to keep the bike straight under way would be negligible,so very little input from the power steering at zero steering angle

russ

[merlot]

Pretty Arrogant Statement.

how do you see arrogance when there is an imoji laughing?

russ

[PinkRosePetal]

.... I don't know for sure but it makes sense to me that a long radius turn at high speed will prompt more assist than a short radius turn at slow speed.

I would have thought it would be the opposite.

[PMK]

how do you see arrogance when there is an imoji laughing?

russ

The emoji selected, posted after the words you used, does not represent humor, but rather insulting laughter at others.

A laughter emoji never equates as a get out of jail free card.

As you do indicate though, there is certainly an amount of misinformation that has been posted. Time will tell how all of it sorts out.