Setup question

[Bobmws]

The scenario:
On most roads the rig drives straight & true. I find if I am in the left lane of a divided 4 lane local road the crown makes me have to correct constantly, rig pulls to the left. I find the same to be true on the left lane of an interstate, though not as severe a pull, obviously less crown angle. I don't intend to sit in the left lane on the interstate, but I do find the left on a local divided highway to flow smoother, and I normally will run that lane.

The setup question:
My rig was setup at Hannigan's shop. I watched the alignment and the bike was set to 2 degree leanout. The car has the electric camber control that has about 3 inches of travel. The alignment/leanout was done with the ECC bottomed out. My thought is if I raise the car about 1" with the ECC and then reset the leanout to 2 degrees I will have some correction available for the left lane excursions.
The potential fly in the ointment is "I" feel the front spring is not heavy enough. I have the heavier sport spring (factory-white) on the bike and they added a spacer to it (maybe 1/4 - 3/8") when they did the steerlite conversion at Hannigan's. The front seems to sag quite a bit and I feel I am always leaning slightly left.
Do I need to up the spring rate/shock before addressing the ECC and leanout?

[shultzy09]

Bob if you are going to up your spring rate by all means do it first.Then check your toe in so you know what it is( .5 - 1 inch? ). Lean your bike in try 4 turns ( pulls left lean right in the US ). Now recheck toe in as it may change,set as it was when you started. Ride and see if it still pulls to the left if so repeat and so on. As far as ECC unit I would keep it bottomed out as you may need it in the right lane high crown or car with heavy load. I hope this helps. Bill

[MIXR]

Bob - The change of my rear shock spring (and only that one) had a huge detrimental effect on the already poor set-up I started with. My belief (based on my experience) is that it is critical to get the spring rates pretty close to what you want before making the finer adjustments.

I've been amazed at how mine reacts to what I would normally consider to be very small variations in road camber, wind direction, load distribution etc. I need a degree of 'softness' for dirt roads, but it is a serious compromise against highway manners. Have fun, and just accept that it may never be 'perfect' for all conditions.

[Bobmws]

Yeah, I thought that might be the case. On the Telelever fork the Steerite plate extends the forks forward to gain trail, also effectively lowering the front end. BMW suspension is somewhat soft and with the weight of the hack and the already lowered front it just seems to drop, or sag too much in frront. The rear spring is adjusted up and doesn't seem to drop very much.
One thing I believe I read here is that ideally the lean should be adjusted with the rider 's weight on the bike. I know you'll correct me if I'm mistaken! The bike lean was set without anyone on it. But as I said it does track true in most right lane situations.....
Again I'm thinking (dangerous, I know) that with the front height restored, or sag set correctly, what I perceive as additional lean out may disappear and the problem will be solved.
Anyone with a GS replaced front shocks with a slightly longer unit to regain height, or have you just increased the spring rate?
Found this link on another thread: http://www.sidecar.com/mbbs22/forums...osts=15#M21151
Though dated it has some great information. Guess I'll take the rig to the truckstop and get some weights, then call Klaus.It's only $$$$$ (sigh)

[Bobmws]

After my tire mounting fiasco today I realize that the rear shock has too much sag also.With 18K on the stock shocks I don't think they'll go too much further with the sidecar attached, not worth the effort to just upgrade the springs.

[Bobmws]

After remounting the rear Avon I took some measurements while I still had the jack under the bike. From full suspension extension, bike jacked up, to sitting static after boucing the suspension a few times the front dropped 2" and the rear dropped 1 3/4". With my dead ass on the bike, again with a few bounces, the front dropped an additional 1 3/4" and the rear dropped an additional 2".
Once I get some weights from the truck stop scale I'll have some info to use to get the proper springs.

[Bobmws]

Got some weights today, nice to have a neighbor that manages a sand plant with digital scales! Filled the tank and the 3 gallon cell on the rear rack. Had my tankbag with it's normal load, my dead ass with full gear and 140 pounds in the hack. I figure there will be another 20-30 pounds on the bike when I'm loaded for a trip, the saddle bags were empty, and maybe another 20-40 in the hack.

Total weight: 1360 lbs.
Front wheel: 440 lbs.
Rear wheel: 720 lbs.
Hack wheel: 220 lbs.

Time to make some calls.

[BMWzenrider]

Originally Posted by Bobmws

Total weight: 1300 lbs.
Front wheel: 440 lbs.
Rear wheel: 720 lbs.
Hack wheel: 220 lbs.

Ummmm......

440 + 720 + 220 = 1380 lbs. on my calculator....

Jus' sayin'.....

------------

For comparison purposes, here are the numbers that I got when I threw my rig on a digital truck scale during one of my trips. It was my first big trip with the new rig and I was fully loaded on that run with lots of gear and a full set of tools stowed in the trunk of the sidecar, and with my wide load planted on the seat of the bike.
My numbers are pretty close to yours, except for the balance between the rear wheel of the bike & sidecar wheel. I am sure some of that is due to the extra weight of the sidecar and my camping gear.
These days I don't carry as much gear in the sidecar when I travel with the rig, so the sidecar is probably a good 30-40lbs. lighter than when these weights were obtained.

Rider & cargo:
Total Weight: 1360 lbs.
Front Wheel: 420 lbs.
Rear Wheel: 650 lbs.
Hack Wheel: 290 lbs.

-----

Since your K12 rig is pretty much a road-going only rig you can get away with a stiffer set of springs and more damping which will give you better cornering, but will feel a lot more choppy on rough roads. And if you go with slightly shorter shocks and reset the sidecar to accomodate the new suspension height it will corner much better due to the lower center of gravity. Lots of options if you are going with complete replacement units.
I am sure that Klaus will ask you about your preferred riding/comfort style.

I have found that I really enjoy having the Electronic Suspension Adjustment (ESA) on my rig's tug.
On dirt/gravel or rough roads I can set the suspension to "Comfort" and get a softer spring at the rear and softer damping at both front and rear.
When attacking the twisties I crank it up to the "Sport" setting which tightens up the rear spring rate and the damping at both the front and rear shock. It makes a noticable difference in cornering flatness.
I have thought about going to an aftermarket set of shocks, but really don't want to give up my ESA.

[Bobmws]

Originally Posted by BMWzenrider

Ummmm......

440 + 720 + 220 = 1380 lbs. on my calculator....

Jus' sayin'.....

------------

For comparison purposes, here are the numbers that I got when I threw my rig on a digital truck scale during one of my trips. It was my first big trip with the new rig and I was fully loaded on that run with lots of gear and a full set of tools stowed in the trunk of the sidecar, and with my wide load planted on the seat of the bike.
My numbers are pretty close to yours, except for the balance between the rear wheel of the bike & sidecar wheel. I am sure some of that is due to the extra weight of the sidecar and my camping gear.
These days I don't carry as much gear in the sidecar when I travel with the rig, so the sidecar is probably a good 30-40lbs. lighter than when these weights were obtained.

Rider & cargo:
Total Weight: 1360 lbs.
Front Wheel: 420 lbs.
Rear Wheel: 650 lbs.
Hack Wheel: 290 lbs.

-----

Since your K12 rig is pretty much a road-going only rig you can get away with a stiffer set of springs and more damping which will give you better cornering, but will feel a lot more choppy on rough roads. And if you go with slightly shorter shocks and reset the sidecar to accomodate the new suspension height it will corner much better due to the lower center of gravity. Lots of options if you are going with complete replacement units.
I am sure that Klaus will ask you about your preferred riding/comfort style.

I have found that I really enjoy having the Electronic Suspension Adjustment (ESA) on my rig's tug.
On dirt/gravel or rough roads I can set the suspension to "Comfort" and get a softer spring at the rear and softer damping at both front and rear.
When attacking the twisties I crank it up to the "Sport" setting which tightens up the rear spring rate and the damping at both the front and rear shock. It makes a noticable difference in cornering flatness.
I have thought about going to an aftermarket set of shocks, but really don't want to give up my ESA.

This scale is calibrated in 20 lb increments, it was tough to get just the hack wheel on the scale by itself. Any of those weights could be up to 19 lbs. higher. I suspect the hack wheel is reading light because of it being just barely on the edge of the scale. I had a 40 lb bag of salt in the trunk along with a 20 lb tool bag, a 40 lb bag on the seat and one more on the floor directly in front of the seat. As I rode across the scale the total weight varied from 1320 to 1380, but seemed to settle at 1360 each time I stopped.

There is actually a used set of Wilbers for sale that are 1/2" shorter for a good price. I'l have to call Klaus today and speak with him. Thanks for the tip on the shorter shock.

[BMWzenrider]

Originally Posted by Bobmws

This scale is calibrated in 20 lb increments, it was tough to get just the hack wheel on the scale by itself. Any of those weights could be up to 19 lbs. higher. I suspect the hack wheel is reading light because of it being just barely on the edge of the scale. I had a 40 lb bag of salt in the trunk along with a 20 lb tool bag, a 40 lb bag on the seat and one more on the floor directly in front of the seat. As I rode across the scale the total weight varied from 1320 to 1380, but seemed to settle at 1360 each time I stopped.

There is actually a used set of Wilbers for sale that are 1/2" shorter for a good price. I'l have to call Klaus today and speak with him. Thanks for the tip on the shorter shock.

Maybe it was just a typo in your original posting then when you listed total weight as only 1300-lbs???

In your orginal numbers it looks like there is an extra 80-lbs when you add the total of the individual wheels together vs. the overall total weight...

-----

I realize that many truck scales are built like a raised lane or bridge, which can make getting the individual wheel weights for the rear and hack tires on rigs without much lead a challenge.
What I have been able to do is maneuver the rig on the scale to be at more of an angle to allow one wheel to be on the scale platform by itself, or even get the rig sideways to put just the sidecar wheel farther onto the platform by itself.

When I obtained the above weights for my rig, I also played with the electric camber control when I had just the rear and hack tires on the scale and found that it actually DOES transfer weight back and forth.
On my fully loaded rig, the Hannigan ECC (which only provides about 3" of suspension lift) creates about +/-20lbs. of weight transfer between the rear tire of the bike and the sidecar wheel when going from full up to full down.
That equated to about a 7% weight transfer on/off of the sidecar tire, which is not insignificant in terms of weight balance for cornering dynamics.

[Bobmws]

Originally Posted by BMWzenrider

Maybe it was just a typo in your original posting then when you listed total weight as only 1300-lbs???

In your orginal numbers it looks like there is an extra 80-lbs when you add the total of the individual wheels together vs. the overall total weight...

-----

I realize that many truck scales are built like a raised lane or bridge, which can make getting the individual wheel weights for the rear and hack tires on rigs without much lead a challenge.
What I have been able to do is maneuver the rig on the scale to be at more of an angle to allow one wheel to be on the scale platform by itself, or even get the rig sideways to put just the sidecar wheel farther onto the platform by itself.

When I obtained the above weights for my rig, I also played with the electric camber control when I had just the rear and hack tires on the scale and found that it actually DOES transfer weight back and forth.
On my fully loaded rig, the Hannigan ECC (which only provides about 3" of suspension lift) creates about +/-20lbs. of weight transfer between the rear tire of the bike and the sidecar wheel when going from full up to full down.
That equated to about a 7% weight transfer on/off of the sidecar tire, which is not insignificant in terms of weight balance for cornering dynamics.

Fixed the typo in the original post, sorry for the confusion...fat finger typing!
I did the same maneuvering to get the hack wheel alone on the scale, didn't play with the ECC though. I truly suspect the hack wheel weight is closer to 240 than 220. At this time I am not replacing the hack shock as it has only 5k miles on it.

Spoke with Klaus about bike shocks, the cost of new Hyperpros set up properly is just slightly above what it would run to rework the used Wilbers (plus purchase price), and the new shocks are warrantied and include the first service. Interestingly, he is considering adding a hack to his K12RS. I referred him to Claude.

Picked up the new 195/45-17 Yokohama S-Drive yesterday, will mount on Saturday as I have the S/TEP class today & tomorrow. Dealer calls it Unique-ohama as it's the only tire available in this size........

[claude]

If you are going to mess with checking the loads on the three wheels the best way, by far, is to use three feed bag type scales at the same time.This is the only really accurate way to do this. Yes, you will get numbers to play with either way but it will only be in the riding that the good or bad will come out. Dynamic operation is what counts above all else and it will be affected by variations such as road conditions, wind, weight in th esidecar etc etc,

The ECC does a gfood job of fine tuning for raod conditions. We have been with Hannigan Motorsports for a long time and we always recomend the ECC off their option list. Some folks use them a lot and some very little.

An anti swaybar if built right is also a great self compensator for various situations.

Taking some lean out away from the bike as was mentioned early on is a good way to go. It is simple and easy to do and it is also easy to return it to th epresent settings if desired.Once shocks are changed you may go through the same process again to dial things in.

[Bobmws]

Originally Posted by claude

If you are going to mess with checking the loads on the three wheels the best way, by far, is to use three feed bag type scales at the same time.This is the only really accurate way to do this. Yes, you will get numbers to play with either way but it will only be in the riding that the good or bad will come out. Dynamic operation is what counts above all else and it will be affected by variations such as road conditions, wind, weight in th esidecar etc etc,

The ECC does a gfood job of fine tuning for raod conditions. We have been with Hannigan Motorsports for a long time and we always recomend the ECC off their option list. Some folks use them a lot and some very little.

An anti swaybar if built right is also a great self compensator for various situations.

Taking some lean out away from the bike as was mentioned early on is a good way to go. It is simple and easy to do and it is also easy to return it to th epresent settings if desired.Once shocks are changed you may go through the same process again to dial things in.

What, pray tell, is a feed bag scale?
I think I know someone at a race shop that has individual wheel scales. I'm just trying to get close so Klaus has an idea for spring rates.
I'm planning to get the hack body painted this month, so my intent is the change the shocks out at that time and check or change the lean out then.
Do you have any ideas for building a bar for this type of road rig?

[BMWzenrider]

Originally Posted by Bobmws

Fixed the typo in the original post, sorry for the confusion...fat finger typing!
I did the same maneuvering to get the hack wheel alone on the scale, didn't play with the ECC though. I truly suspect the hack wheel weight is closer to 240 than 220. At this time I am not replacing the hack shock as it has only 5k miles on it.

Spoke with Klaus about bike shocks, the cost of new Hyperpros set up properly is just slightly above what it would run to rework the used Wilbers (plus purchase price), and the new shocks are warrantied and include the first service. Interestingly, he is considering adding a hack to his K12RS. I referred him to Claude.

Picked up the new 195/45-17 Yokohama S-Link yesterday, will mount on Saturday as I have the S/TEP class today & tomorrow. Dealer calls it Unique-ohama as it's the only tire available in this size........

Once you start doing any even moderate cornering with your rig, especially once you have some new/rebuilt shocks on the bike you will find that the stock spring/shock unit supplied on the Hannigan sidecar is woefully inadequate.
Especially if you start getting into rapid side-to-side transitions while the sidecar is loaded. The damping on the thing is pittiful, and non-adjustable. Your sidecar will start to wallow out there like some large drunk lumbering beast.

Once you get confident enough to do any spirited cornering you will be positively BEGGING for a better damper out there on the third corner!
Trust me on this one... if you are going to the effort to improve the suspension on the bike, go ahead and bite the bullet and do the sidecar wheel at the same time. Otherwise it will all come apart on you in the corners if you have a weak shock out there on the sidecar. Your side-to-side damping/roll will be all cat-e-wampus and unpredictable.

-----

As far as installing the S-Drive onto the stock wheel, I will be interested in hearing how that works out. How much pressure it takes to seat the beads would be one thing in particular that I would like to hear.

The stock wheel for your bike is 5.5" wide with a 180/55R17 tire on it.
The Metzler Z6/Z8 specifications list its dimensions as 7.0" wide by 24.8" diameter when mounted on a 5.5" rim.

The 195/45R17 S-Drive is rated for a 6-7.5" rim and gives its dimensions as 7.8" wide by 23.9" diameter when mounted on a 6.5" wide rim.

Now, the diameter is not really going to change due to the radial construction of the tire, but the maximum sidewall width will be pinched in a little bit when mounted on a narrower rim. The rule of thumb is that for every 1/2" of rim width, the max. tire width changes by approximately 1/4". So by mounting on a rim that is 1.0" narrower than the "measuring rim" for the S-Drive tire, it should pinch in the sidewalls as much as 1/2", bringing the final section width down to 7.3", which is right in the ballpark of the Bridgestone Batlax BT020 tire in 180/55R17 which has a spec. width of 7.2" and fits.

As far as the diameter, you will now be running a tire that is about 3.6% smaller diameter than stock. In my opinion, that is a good thing, as the weight and extra aerodynamic drag of adding a sidecar changes the power & torque demands at any given speed.
In fact, I am currently running 13-15% lower gearing on my rig (5% in the final drive, and the rest depends upon summer or winter tire).
And on my previous rig which had lower horsepower I ran it at 20% lower gearing than the stock solo gears.
In both cases, going to lower gearing actually INCREASED fuel efficiency because I was then running the engine in the proper RPM band for the load.

As far as your speedometer/odometer, if the speedo is anything like most BMWs, it will be reading even MORE optimistic than normal after the tire change, so you will either need to use a GPS to know your true speed, or enjoy the fact that you will get fewer "performance awards" because you aren't really going as fast as you think...
As for the odometer, I don't worry about the couple of percent error and just do my maintenance based upon what it says on the clock, not actual miles. It would just get too confusing trying to keep track of the conversion/next interval. And doing your services a little early is never a bad thing.

[BMWzenrider]

Originally Posted by claude

If you are going to mess with checking the loads on the three wheels the best way, by far, is to use three feed bag type scales at the same time.This is the only really accurate way to do this.

I am going to have to disagree with you on this one Claude.

I understand what your logic is, that any time you put a single wheel or axle on a scale that the scale deck deflects downward.
That in turn changes the attitude of the vehicle. In essence, tipping it in the direction of the wheel/axle being weighed, and transfering weight onto it.
Your idea is that by having each wheel on its own scale deck at the same time that this effect is minimized because all wheels go down, eliminating (or at least reducing) the change in attitude of the vehicle that would change the weight bias.

However, modern electronic platform truck scales use strain guage technology which requires almost no deflection in order to read the load. So they work pretty well at isolating individual axles without altering the attitude of the vehicle.

That can be seen in the very good correlation that is obtained in the numbers that both Bob and I got when we put our rigs on this type of scale.
When you take and add together the weights of each wheel weighed by itself, the sum equals the total measured weight within the +/- accuracy margin of the scale for both of us. Mine came out dead-on, and Bob's numbers were within the 20-lb tolerance of the scale after adding together three measurements.