Some questions on Alignments - can anyone help?

[rich46]

Hello All,

I always get good advice here so please forgive the FNG but I have a couple of questions that I do need answers to. First off (I'm not bragging just letting you know I do understand vehicles) I have worked on Race Cars, Racing Motorbikes and Sidecar outfits. So here are my somewhat stupid questions. Before asking I'll first say that I will order a True Laser tomorrow morning (not just for my new F-3 but I can see that it will help with setting up the Sidecars also.) so here are my questions:

1. I have been looking at the shop manual and I think I could at least do something with the Bump-steer. Any reason that's a bad idea?

2. What do most of you find as the best specs as far as front toe should be? I have weights so I can replicate the riders weight so I'm looking for the specs for a bike with rider.

3. I have gone with the Laser because most other instructions (Workshop BRP man.) want me to use the chassis as a measure point. I hate that thought because all OEM stuff might have been made on a Friday by Elves and not be perfect...... if/when it comes to CanAm's - am I correct in my thinking ?

4. Here I beg you to keep in mind that I haven't worked at a dealer since the early '70's (but please feel free to laugh) what pray tell is a BUD's and what is SAS? Everything I've touched since then has never been near a DMV much less a DOT station.

Just one other addition - the 2022 F-3 has a Lamonster swaybar and a pair of stage 3 front shocks if that changes anyone's advice.

Thank you all for the help you have been in the past and any help you can be with these questions.

Cheers :bowdown: :bowdown:

 

[Peter Aawen]

Without really working at it rich, there's not really such a thing as a 'stupid question', just 'stupid answers', and I can give you/show you plenty of them! However, I'll have a shot at giving some helpful answers here...

1. There's no reason at all! I'd be very interested to see what you come up with. :thumbup:

2. Some use degrees, but all the rigs/set-ups I use work off the thrust alignment & use millimetres - and depending upon how passive or responsive the rider wants their Spyder to be, I generally use 1-2mm of Total Toe in, altho I have been known to crank that up to 3mm for a Track Day on tires that someone else is paying for!

3. As far as I'm concerned, you are correct in your thinking! So it pays to make sure you've done any rear wheel/belt alignment BEFORE you do your front wheel alignment, so that you don't change the drive/thrust alignment after you've done all that work up front & render it sorta wasted! :shocked:

4. BUDS & BUDS II are BRP's proprietary 'Universal Diagnostic System' - BRP Universal Diagnostic System - there's the original version & the update version, BUDS II that came into being/use about 2017 (?? :dontknow: someone please correct that date if I'm wrong ) As for 'SAS', I'd need a bit more context to answer that one... :dontknow:

And as for your additional info, good to know & have those fitted, they'll make your riding more stable & enjoyable, as well as allowing for some fine tuning of your ride via the shocks, but really make no difference to any of the above or to your proposed wheel alignment. :thumbup:

Over to you... :cheers:

 

[rich46]

Peter,

Thank you for the information. I do prefer to use mm as it seems to be a simpler method. The 1 to 3 mm seems far more reasonable (more like the Formula cars I've worked on). I will surely let you know what I find in regards to Bump-steer. Not yet sure it can be done but I've done Triumph Spitfires and Bugeyed Sprites so if there's a will.

As far as the SAS what was said was to use the BUDS to reset the SAS. Could that be some form of error call up for steering angle ?.

Do love your end of the planet we've raced our vintage motorbikes at PI and if they are going to do another Classic we'll be back. Last time we were there we quite lucky in that one of our competitors was part of the Vincent Firm and we were invited over for a tour of the shops and a view of the new machines.

Cheers

 

[PMK]

Rich, as you may be noticing, your PM of questions to me regarding alignments and ROLO equipment, plus ROLO alignment specs differs dramatically from other methods. ROLO specs are projected well forward of the uprights, axle established center point.

I have accomplished alignments utilizing both my ROLO setup and toe sticks with tapes. Each requires knowing the optimum settings for the equipment being utilized for the task. Both typically require resetting of the electronics via BUDS or BUDS2. Witnessing partial travel bump steer while accomplishing alignments validates it does exist.

SAS = Steering Angle Sensor

Spyders utilize two electronic sensors regarding the steering system. One measures the angular movement in each direction from center and establishes the null setting. The second, on account of Spyders utilizing an electric style power assist, there is a torque sensor that monitors input forces, either from the bars or the wheels. This too should be reset for optimum performance of the steering system.

If, as you mentioned in the message you had sent me, you follow through on determining bump steer dimensions on a stock Spyder, with plans to correct it, you should also determine the front suspension roll center and optimize that while correcting bump steer. You might also consider fabricating replacement suspension arms that flex less. Under braking, the A Arms of the Spyder are easily distorted. This very likely is a contributing factor of uncontrolled inputs to the steering while cornering.

Had BRP / Can Am opted for a wider placement of the inboard tie rod ends, using a sliding rack type design with applicable ratio for a motorcycle handlebar movement, bump steer would be almost nil. Unfortunately, by utilizing a Kart style steering bellcrank, that does offer Ackerman effect, they got a portion of it correct at minimal complexity and expense. Their saving grace being the Spyders minimal wheel travel similar to a race Kart.

Out of the box, the Spyder chassis is acceptable for its intended purpose as a touring machine (RT series) or cruiser (F3 series). Yes, bolt on improvements can be made that work well for some riders, but may be less than optimum for other riders.
Essentially though, a properly setup chassis alignment is adequate for the intended purpose. If you plan to closed course compete on winding circuit, then yes, the efforts of major changes will offer up good results. For most though, replacement automotive tires running appropriate pressures, possibly a firmer front swaybar, and in some cases upgraded dampers and springs will be adequate for the majority of riders.

All the best with your project.

 

[PMK]

Without really working at it rich, there's not really such a thing as a 'stupid question', just 'stupid answers', and I can give you/show you plenty of them! However, I'll have a shot at giving some helpful answers here...

1. There's no reason at all! I'd be very interested to see what you come up with. :thumbup:

2. Some use degrees, but all the rigs/set-ups I use work off the thrust alignment & use millimetres - and depending upon how passive or responsive the rider wants their Spyder to be, I generally use 1-2mm of Total Toe in, altho I have been known to crank that up to 3mm for a Track Day on tires that someone else is paying for!

3. As far as I'm concerned, you are correct in your thinking! So it pays to make sure you've done any rear wheel/belt alignment BEFORE you do your front wheel alignment, so that you don't change the drive/thrust alignment after you've done all that work up front & render it sorta wasted! :shocked:

4. BUDS & BUDS II are BRP's proprietary 'Universal Diagnostic System' - BRP Universal Diagnostic System - there's the original version & the update version, BUDS II that came into being/use about 2017 (?? :dontknow: someone please correct that date if I'm wrong ) As for 'SAS', I'd need a bit more context to answer that one... :dontknow:

And as for your additional info, good to know & have those fitted, they'll make your riding more stable & enjoyable, as well as allowing for some fine tuning of your ride via the shocks, but really make no difference to any of the above or to your proposed wheel alignment. :thumbup:

Over to you... :cheers:

Regarding your words mentioning fine tuning the ride via front shock adjustments, it should be mentioned that increasing or decreasing spring preload / altering ride height, even a small amount on a Spyder, has a legitimate measurable change of the toe setting that must be realigned back to the desired toe setting.

In regards to making clicker changes of the dampers, while not directly responsible for altering the mechanical dimension for toe, damping changes on a Spyder may alter how the chassis reacts in regards to compressing or rebounding the front suspension, which can interact with the settling chassis bump steer reaction to the steering angle and steering input.

Simply parameters not often considered on a decent handling Spyder. However often we read about a twitchy ill handling Spyder that was transformed by replacement shocks or a swaybar. These items have the ability to control where the chassis settles while cornering, and do result in possibly obtaining a better toe setting from bump steer induced toe change.

 

[rich46]

PMK,

Thank you for your thoughts. Much of what you have alluded to makes total sense and I can see there are many levels of improvement depending on the amount of effort one wants to apply.

As I have a shop almost full of race motorbikes I can't spend weeks developing new suspension arms nor do I want to rework the steering system to allow for close to zero bump-steer. I have taken a look at as many views of the steering as I could find and even as I would prefer rack and pinion I do think that there are some things I can do to improve the bump/droop curve. The trick here would be to format the changes to allow for different riding styles. I have found that drivers with a very sensitive braking technique, who trail brake into turns prefer far less toe out under full bump than the folks who hard brake in a straight line ( like snow plow in skiing) and then turn the machine.

I am about to order the Laser gear and luckily have all the other equipment I will need. I am approaching this like I would a production racer not a full-on ground-up racer. Making do with what's there not reinvent the bloody thing.

When I scale the bike do you have any feeling as to what kind of weight bias I can expect and what do you consider optimal ? One other question I have is; the ride height feels good as it came from the dealer if for no other reason than it does bottom out on speed bumps but not very often nor very hard. Low enough but not too low.

Thanks for the in-put and information. For me this is a thing I'm enjoying the tinker with but now that the plague has lessened we are planning on getting back to "Old Guys" vintage motorbike racing so I want to keep my Spyder for short parts runs and not scattered about the garage in development.

Cheers

 

[PMK]

Rich, Regarding weight bias front to rear, or lateral weight on wheels, honestly I have no information or care to guess what numbers your scales may read. I do have access to very accurate aircraft scales, but never considered weighing, since other than rider and passenger weights, there is no means to shuffle weight for a more optimum setup.

Regarding ride height, I have seen a hard dimension from Can Am, but do not recall it without researching to find it.

As time permits, I do plan to measure A Arm angles of our current setup, make a change, going to the Can Am spec, and then, change to what I hope will be a more optimized setting, as the chassis settles into a corner. Our current setup is very good. When riding two up, the one issue becomes the initial settling of the chassis when turning more abruptly, or hard fast cornering. This induces enough instant chassis lean to slightly toe out the outside front wheel. Thus creating an instant twitch outward, until the chassis fully settles. My goal of altering ride height to a more optimum setting, will be to retain my existing minimum toe in, while avoiding toe out as the chassis settles under hard cornering. I could easily eliminate that hard cornering twitch while riding two up by increasing toe in. However, doing so surrenders the remaining 99.9% of ride time with less than optimum toe in. That less than optimum toe in, as you know reduces rolling efficiency and speed while increasing tire scrub / wear. The rider, or rider and passenger, represent a very large percentage of gross vehicle mass. Additionally, that mass is positioned to raise the CG significantly. Ideally, optimizing A Arm angles can lower the CG while gaining a more comfortable instantaneous front roll center. In simplest terms, I hope to get the Spyder to corner more flat with less chassis lean, resulting in less induced toe out from bump steer.

As I mentioned it is very good as is, and this project will be waiting until I get a few aircraft and race bike projects done, along with weekly chores to maintain the yard / house.

After realigning a friends Spyder that had been aligned to commonly accepted settings, I cautioned him that he should expect the Spyder to be more free rolling when slowing to a stop. He called later that night after his Spyder was re aligned. His comment being how it did simply keep rolling vs slowing from tire scrub. His tires were showing some wear and that is why his alignment was checked.

I will say that one aftermarket suspension company does increase front wheel travel. They accomplish this in the extension direction. It should be expected that doing so will increase the bump steer amount, and also allow a greater chassis lean angle.

Again, all the best with your changes, and yes, please keep me informed of your progress.

 

[rich46]

PMK,

Thank you again. Information is a good thing as we all learn from each-other.

Not sure what aircraft scales are. What I use are four scale pads that can be leveled individually. The system is computerized and will give you; corner weight, front/rear weight and %, cross weight,gross weight and the amount of ride change and weight % change.

When it comes to bump-steer (this is not referring to high end formula one and two race cars where bump-steer is far easier to adjust) depending on the system you can almost always do something with bump-steer. On some vehicles it can take a lot of thought and on some even a lot of component fabrication. I will say that if there is a lot of toe change during bump and droop in most instances if you are looking for high end performance it is well worth the effort.

Now please understand that I like doing this sort of work and for the normal street rider just getting their Spyder within factory specs is all they'll ever need to do to enjoy their bike.

So back to bump-steer. What I've found on most production vehicles is that when you get the thing bump steered as best as you can you'll end up with a toe graft that is a "S' from full bump to full droop. From what I've read here, when the Spyder's toe is set to a toe-in spec at ride height it will start to toe-out when loaded. If this is true then that does seem logical. The bike will brake better (snow plow the wheels under braking) and if not to dramatic will track in a straight line.

What I will try and do is flatten out the "S" so that toe changes will transfer less in-put to the steering. This also allows for moving where the changes start (bump to droop) to fit the rider's preferences.

Again I'm not sure that I can really make a huge difference but as I said it's the kind of thing I just enjoy playing with and if it turns out to be worthless or impossible then I put everything back to OEM and just enjoy my Spyder.

Cheers

 

[PMK]

Rich
Aircraft scales come in various types, some types, the load cells are placed on top of the jacks, the aircraft is raised via the three jack points and weigh the aircraft with wheels off the ground. Others, the type I might use would be low height platforms with load cells. Essentially you get weight values and need to calculate bias.

You will know before me whether the Spyder graphs as an “S” or more straight line plot. No doubt at laden ride height as adjusted toe, there will be a plot of toe in during suspension extension and going toe out under compression. How much “S” the graph plots might be interesting, but suspect a reasonably steep straight line plot of toe change vs suspension movement.

In regards to Spyders, I learned ling ago they are not racers. My setup utilizes a toe setting that I derived from test rides. It works excellent locally. I do plan to add a slight bit more toe in, in an effort to eliminate a slight twitch of toe out as the chassis settles into fast corners with a tighter radius. Also, this may help eliminate minor wiggles under extremely hard braking events.

I am confident that with the ability to laser align, and based on your experience, you will test ride easily to a great setting for your machine.

Our Spyder was horrible as delivered. Hang on tight or get tossed off. My experience racing Karts had me immediately know what was going on. A few adjustments, and the Spyder was hooked up. Installing aftermarket front shocks did raise the front ride height slightly. Doing so it added toe in. Certainly this added stability when cornering and even straight line too. Unfortunately, the slight toe change could be felt as tire scrub, and the Spyder did not roll / flow as freely as before.

You will dial yours in. Likely take an afternoon of test riding and adjustments. Overall, Spyders are simple to work on, so do a laser alignment, note the settings. From there find your magic setting by quick small adjustments and test rides. Once the toe “feels” good, measure that setting. Then do a full alignment to that value.

BTW, realize, the rear wheel plane of rotation, and thrust alignment down the chassis centerline may not happen. Rear wheel alignment is derived from belt alignment. Therefore your thrust alignment may be angled left or right. This allows you to test ride for best settings, THEN final align.

As always, all the best with it. Should be a relatively easy, interesting fun project for you.

 

[rich46]

PMK,

Something I noticed right off and I be you felt right away was the built in push. When I first started racing sports cars all we'd do was weld the spider gears and lock the rear end. This was before you could get LSD or locker third members. The first time I started really driving the bike on winding back roads I found myself running out of black-top.
Here is a handling issue that we are stuck with. Because of this one thing limiting (as much as can be limited) outside wheel (in-bump) toe-out will help a lot. I think this is why so many folks feel as if the much thicker sway-bars help so much.

 

[PMK]

PMK,

Something I noticed right off and I be you felt right away was the built in push. When I first started racing sports cars all we'd do was weld the spider gears and lock the rear end. This was before you could get LSD or locker third members. The first time I started really driving the bike on winding back roads I found myself running out of black-top.
Here is a handling issue that we are stuck with. Because of this one thing limiting (as much as can be limited) outside wheel (in-bump) toe-out will help a lot. I think this is why so many folks feel as if the much thicker sway-bars help so much.

Regarding the Spyder, there is one time only that true understeer occurred. True understeer as in the front tire turn in angle was greater than the line the tires held. A true front push. This happened with oem Kenda tires, testing lower pressures. The tires felt as if the outside tire began to tuck under the rim onto the tires sidewall.

Regarding what you mentioned in terms of toe out, in simple terms, you get that wavering during straight line runs. As the Spyder is cornered, with toe out, the inside tire is already turned inward and stable. The outer front tire will transition from toe out, to neutral to toe in as cornering happens. As the tire angle becomes zero, any bump or chassis lean will wave the tire causing instability. Depending upon how much toe out exists, the feel can be even very twitchy and nervous cornering.

When set up with toe in, the outside tire is already pointed to the corners inside. The outer tire, which also sense bump steer toe out, will ideally remain pointed to the corners inside. As the inside tire transitions, is senses less bump steer and less weight. Therefore, while not perfect, the change as the machine corners is almost not noticed.

 

[rich46]

PMK, I'm sorry but I view the the definition of under-steer/over-steer as the one I received in school. It is the difference between steering in-put and direction of travel. You can not remove one end of the vehicle from the other. As long as the rear wheel has traction it will attempt to drive the vehicle in the direction it is pointed. The thing does not want to change direction and the rear does not want to aid in that change.

I have not had the time to run the suspension thru the bump steer curve but if what I've been told is true and a slight toe in unladen setting will change to toe out as the corner is loaded then the inherent nature of these vehicles is going to be push/under-steer. I'm not seeing this a a failure in the Spyder or it's design nor something that under most conditions will even be noticed. In the old days we'd just goose the gas and break the rear loose "presto it goes from under-steer to over-steer." What I was trying to get at (poorly it seems) is that as I try and make the bike work better my aim is to try and limit the toe changes as much as I can without making the suspension so stiff that it is harsh and non-compliant.

I was not attempting to say that there was something wrong in the engineering just the nature of the beast. It is very much the same issue that confronted the fellows trying to race the early Morgans. Being Brits they seemed to find work arounds or just lived with the problem but they did race the heck out of the three wheel versions.

 

[PMK]

Rich, as I stated, regarding understeer, whether power on or power off, the handlebars are turned, but the vehicle may go straight or turns less than the desired input.

In regards to grabbing a handful of throttle to break the rear tire loose, and bring the rear around a bit, our Spyder went sideways with oversteer once. Two things happened, the computer found out and closed throttle, second, my brain found out and reacted in a way to lessen the likelihood of a high side.

No doubt you will have a fun time dabbling with the Spyder. As you dabble, some of the handling “stuff” regarding toe out may present itself to you. My experience finds the Spyder a bit unique in regards to some chassis parameters. Not a car, and not a motorcycle in regards to handling.

Excited that you will test and get dialed in. Again, all the best with it. Be safe when testing also, until you get the toe in close, that handling twitch as the chassis sets can sometimes be snappy and almost violent if not knowing about it.

With the weather cooling a bit, as I mentioned, hopefully I can find time between working on race bikes, jets, and grandkids to better optimize the front roll center on our Spyder, realign to specs I prefer, then see how much more planted the machine becomes. Not difficult, just takes time.