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1/3 sidecar weight rule
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Posted 10/4/2003 7:02 AM (#1035)
Subject: 1/3 sidecar weight rule


Is the rule the hack should weight more than 1/3 of the bike's weight. The Ural the hack weight is greater than 1/3 of the bike's weight. With the entire line of Suzkui fited with a Ural sidecar is greater than 1/3.

Can the hack weight almost 2/3 of the bike's weight?

Example: Savage 650 (352 lbs) ural hack (225 lbs)

Thanks
Charlie
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Joyce
Posted 10/4/2003 10:05 AM (#1036 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule


Hi Charlie,While I shy away from most technical discussions, I have a little personal experience with a 1987 650 Savage. Ours has had several sidecars attached to it over the years, first was a Friendship 1, second a Jupiter, and now a Ride-by-Side(Texas Sidecar Standard Model).That little savage pulled all three, but the smaller sidecar lets you run with rest of the group, pulls hills without downshifting and it a great fun rig. Last year we mounted a Ural to a '90 Intruder 1400 and it is a super combo and it probably doesn't fit the 1/3 rule either.
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Hack'n
Posted 10/4/2003 6:30 PM (#1037 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule



Posts: 4833
Location: Boise, Idaho
I think the old "Rule of thumb", 2/3ds bike to 1/3 sidecar ratio is one of the old "Urban Myths" that people pass on without knowing why. The original idea was probably someone's idea of an ideal balance between the size of the mororcycle as related to the size of the hack, so neither would overpower the other. This ratio will usually give one a rig which will keep all three wheels on the ground under normal (or moderate) driving conditions without any big surprises, and the pilot most likely won't have to hang off in all the corners which makes for a more pleasant ride for most of us. Also the bikes power, wheels, tires and brakes should be adequate enough to handle the stop, go and side-loading chores that will be demanded of it. This approximate loading "Ideal" can also be achieved by added ballast if desired.
Others may feel free to disagree with this, but that's my "scald" on the matter. I'm no engineer, but I've been on a lot of freight trains!!!

Hack'n
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claude #3563
Posted 10/4/2003 6:50 PM (#1038 - in reply to #1036)
Subject: RE: 1/3 sidecar weight rule



Posts: 2480
Location: Middleburg, Pa
joyce wrote:
>>Last year we mounted a Ural to a '90 Intruder 1400 and it is a super combo and it probably doesn't fit the 1/3 rule either.<<

Don't know about a '90 intruder but a 2002 is listed at 535 pounds. The Ural sidecar is a little over 200 pounds I think. More than the third deal.
I do not know where the 1/3 rule came from but it has been quoted and requoted many times with no explaination. I really beleive that the system Hal speaks of to see if a rig is stable or not is much more accurate. To just say a sidecar should weigh a third or more of the bike weight does not consider a few key things. Rider weight being one of them. If we took a rig with a 200 pound sidecar on a 600 pound bike and stuck a 300 pound rider on it it would be a far different outfit than if the rider only weighed 100 pounds. Poor example but I think the point is clear.
The distance the sidecar is mounted from the bike is also a factor. As is the suspension on the bike itself..if that 300 pound sidecar pilot jumps on a 550 Honda with stock suspension and a Spirit eagle mounted to it he will NOT have a very well matched rig.
Stand on the left foorpeg and swing your weight away from the bike..if the sidecar comes up slowly it is a stable rig...if the sidecar comes up real quick and doesn't want to go back down..or if you cannot even get your full weight on the footpeg before it comes up the rig IS NOT STABLE. If you cannot hardly make the sidecar wheel come off the ground the rig is stable to the point that it may not be very sporting but could still, of course, be a good touring outfit. (Of course the sheer horsepower the bike itself has is a huge factor here.)
Stability is something that is important to new sidecarists but it is also important to a veteran as well. Yes a light rig can be driven within it capabilites but a rig that is too light can really be an eye opener or worse if that ,unwanted but eventually going to happen ,emergency situation arises. (Decreasing radius turns, blind corners that have debris in them, the deer jumping in front of you, yadda yadda).
Take a look at Hal Kendall's books or his new CD (which Al said would be posted here soon)...good basic straight forward info for all sidecarists new and old alike.
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claude #3563
Posted 10/4/2003 7:02 PM (#1039 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule



Posts: 2480
Location: Middleburg, Pa
Charlie..
To moe directly anser your question I think whatJoyce said was good advice. Point being, correct me if I am wrong Joyce, is that a 650 Savage may just be a llitle underpowered to haul that large a sidecar effeciently. This is not to say that a given light bike cannot haul a heavy sidecar if it has the power to do so. We have an XS1100 with a Motorvation Formuls II on it..not a bad match weight wise nto power wise. I also have a fully enclosed coach body that fits on the Motrvation frame..Now this body is pretty heavy (afraid to weigh the darn thing) but the bike has enough power to pull it very well. (gas milage stinks though from the weight as well as having the aerodynamics of a show box).
Bottom line..there is a consideration related to weight of the sidecar..but there is also a consideration that must be factored in and that is the power of the machine pulling it.
Some may disagree and that is fine..it all comes down to what type of performane one is looking for.
Hope this helps some,
Claude
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Joyce
Posted 10/4/2003 7:57 PM (#1040 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule


Whew Claude, I pretty sure that is just what I said, but you said it a lot longer! LOL
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claude #3563
Posted 10/4/2003 8:05 PM (#1041 - in reply to #1040)
Subject: RE: 1/3 sidecar weight rule



Posts: 2480
Location: Middleburg, Pa
Someday I will learn to shut up... maybe...lol
Claude

Edited by claude #3563 10/4/2003 8:08 PM
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Posted 10/6/2003 10:49 AM (#1052 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule


Thanks All! I wasn't factoring in my weight to the 1/3 rule... The 650 is a little under powered to run with the pack so I guess I'll move up in bike size or find a lighter car. Well my bike's a little old I guess it's time to update...

Thanks again
Charlie

PS: Claude you don't talk too much! You got a lot knowledge to put out and I'm in the process of learning...
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Posted 10/10/2003 7:43 PM (#1096 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule


The 1/3 weight rule is basically to ensure that a light sidecar isn't attached to a heavy motorcycle. This rule assumes an unladen motorcycle and unladen sidecar. A small bike will pull an overweight sidecar, but it will be obviously underpowered. Case in point: the training rigs used in the Sidecar/Trike Education program. Many sites use a 250 Honda Nighthawk attached to a Velorex 562. Now, have an overweight novice climb aboard the bike, and another overweight passenger squeeze into the sidecar, and the human load probably exceeds the weight of the unladen outfit. Still, that's acceptable for learning to drive on a training range.

Out in traffic it's another kettle of fish. Today's traffic is getting so aggressive that I suggest a minimum of 60 HP, and preferably 80 HP. Just about any of today's UJM bikes (such as the Suzuki Bandit 1200) have the HP to pull a hack. But remember that the manufacturer's listed weight is typically "dry" and very conservative. The true "wet" weight of the bike may present a different ratio, and any conversion reinforcements, such as auto wheels, leading link, subframes, etc. should be added to the "wet" weight of the bike.

The weight of the sidecar is more than just resisting rollovers in right-handers. Weight is a good indication of how much steel there is in the frame, axle, struts, etc. Urals are heavy because the main frame is thick, large diameter steel tubing. And the body is heavy guage steel, not lightweight plastic. So, the weight means greater strength and resistance to bending, heavier axle stub, stronger wheels, strong attachment points, etc. That weight is a lot more useful than taking a flimsy sidecar and adding sand bags.

I've seen more than a few sidecar outfits with that famous Eastern European lightweight sidecar attached to a machine such as a full size Harley, or Honda Gold Wing. These are the owners who creep through right-handers backing up traffic, and wondering what can be done to "improve the handling". What's needed is to jack up the sidecar body, install a sidecar chassis that's about twice as strong (and therefore twice as heavy), replace the struts with something twice as heavy, and then install a new sidecar body that's about twice as big (and twice as heavy). Then, it might be possible to align the outfit and get it to handle.

At one time I ran a Honda Ascot 500 single with a flatbed sidecar. I never weighed this outfit, but I suppose the whole thing was maybe 450 lbs, including the bar of lead bolted to the right side of the sidecar frame. I suppose the sidecar fell within the 1/3 rule, but what was much more important was the outfit/driver weight ratio. In turns, it was absolutely essential to hang off left or right to prevent a rollover. While I enjoyed driving this rig locally, it would have been a very dangerous machine for anyone not experienced with the full bag of sidecar handling tricks, such as managing steering reversion. My point is, the weight and skill of the sidecar driver has a lot to do with how far you can deviate from the 30% formula and still arrive at a controllable rig.
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claude #3563
Posted 10/10/2003 9:23 PM (#1100 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule



Posts: 2480
Location: Middleburg, Pa
David wrote:
>My point is, the weight and skill of the sidecar driver has a lot to do with how far you can deviate from the 30% formula and still arrive at a controllable rig.<

True,amen,agree yadda yadda...but...there are limits to what the 'skill' of any sidecar jockey on an unbalanced rig can do in an emergency situation.
It is best to have a rig that is balanced with the rider onboard. It is too bad when it seems so many potential sidecarist get that first rig together and it is so unbalanced they walk away from sidecarring never knowing how much fun it can really be.
Face it folks..a spirit eagle on a boss hoss ain't never gunna work!
Claude
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SidecarMike
Posted 10/10/2003 11:43 PM (#1102 - in reply to #1038)
Subject: RE: 1/3 sidecar weight rule



Posts: 1710
Location: Menomonie, Wisconsin USA
To just say a sidecar should weigh a third or more of the bike weight does not consider a few key things. Rider weight being one of them. If we took a rig with a 200 pound sidecar on a 600 pound bike and stuck a 300 pound rider on it it would be a far different outfit than if the rider only weighed 100 pounds. Poor example but I think the point is clear.
I think it's a perfect example. I've always taken the rule to mean a fully laden rig with it's normal load both on the bike and in the sidecar. Back in my mechanic days we always weighted the auto down with an approximate load before attempting ride height or front wheel alignment. Granted, I worked on smaller cars but the theory is the same.
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claude #3563
Posted 10/10/2003 11:56 PM (#1103 - in reply to #1102)
Subject: RE: 1/3 sidecar weight rule



Posts: 2480
Location: Middleburg, Pa
Another thing that should be considered is the suspension itself. Stock suspensions on many bikes are quite soft so to speak. Stock suspensions on some sidecars are as well. A softly suspended rig (or part of the rig) can mean that the outfit is much more sensitive to various loads put on it. Does this mean that a stiffer suspension can make up the difference for a mismatched rig weight wise...No.
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Posted 10/12/2003 1:26 AM (#1110 - in reply to #1100)
Subject: RE: 1/3 sidecar weight rule


I'm not suggesting a novice start with a lightweight or poorly matched rig. I highly agree that a rig balanced to (approximately) the 1/3 ratio will be much more controllable, especially by a novice driver. But I'll emphasize a couple of concepts: first, a very light sidecar attached to a very heavy bike creates a handling nightmare that can't be "adjusted". Second, sidecar driving skills are a big part of the picture. If you can't do (or don't understand why to do) what's taught in the S/TEP, you are increasing your risks. If you choose to drive an outfit that's extremely light or mismatched, you really need to use all the driving tricks in the book.
One of the exercises in the S/TEP course is to attempt to lift the empty sidecar by standing on the left footpeg and pulling on the handlebars. If the sidecar lifts easily with a 150 lb driver, it's unacceptably light.
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claude #3563
Posted 10/12/2003 7:32 AM (#1111 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule



Posts: 2480
Location: Middleburg, Pa
Dave wrote:
>> One of the exercises in the S/TEP course is to attempt to lift the empty sidecar by standing on the left footpeg and pulling on the handlebars. If the sidecar lifts easily with a 150 lb driver, it's unacceptably light. <<

I would venture to add this..if the wheel does not lift easily with a 150 pound driver but does with a heavier driver, and all else remains the same, it is then not a stable rig for the heavier driver. Another thought is if a rig is stable with the 150 pound driver and he,or she, then puts a passenger on the pillion..it is not going to be a stable rig either (with all else remaining the same ).
It all comes down to being balanced for the weight at hand and a suspension and setup that is suffecient to handle the weight at hand.
Claude
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Hack'n
Posted 10/12/2003 2:31 PM (#1114 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule



Posts: 4833
Location: Boise, Idaho
Charlie, (and others)
I hope we haven't scared you off with all this input. (And you thought this was a simple question).
I, (and probably others), have been getting a considerable amount of e-mail from people who are even more confused after perusing this thread.
Some points being:
Did the 1/3, 30%, or whatever: Rule, law, fiat, mandate or whatever: come down off the mountain with Moses? I say "No, it's a loose guideline with many variables." Then I list some of them.
Is twice as big twice as strong? Again, "No, and neither is twice as heavy twice as strong. (If in doubt, check with Boeing on this one). Heh, Heh, sorry Dave.
Does ballast do any good at all? Ask any Dockmaster.
Can my 300# self and my 200# girlfriend ride on the GL1800 with just her 3 year old girl in the Eagle Spirit hack? "Hell no!"
Will common sense prevail? "I sure hope so, and soon."

In passing, I'll add that we're just trying to be helpful and if you can separate the wheat from the chaff you're gonna have a lot of good times "HACK'N"
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RogerK
Posted 5/25/2009 1:32 AM (#44206 - in reply to #1036)
Subject: RE: 1/3 sidecar weight rule


I noticed you said you mounted a Ural sidecar to a 2000 1400 Intruder. That is the exact match up I want to do. Can you tell me did you have to build a subframe? If so did you fabricate it yourself or did you buy it?
Any help you could give me would be appreciated.
Thanks,
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jabud59401
Posted 5/25/2009 10:03 AM (#44207 - in reply to #1036)
Subject: RE: 1/3 sidecar weight rule



Posts: 18
Location: Great Falls Montana
do you have a picture of the Intruder?
I have a 97 and thought about putting one on it.
I currently have a 1980 FLH with CLE hack
Thanks jabud
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Joyce
Posted 5/25/2009 12:44 PM (#44209 - in reply to #44207)
Subject: RE: 1/3 sidecar weight rule


Here is a picture of the '90.



(DSC00801.jpg)



Attachments
----------------
Attachments DSC00801.jpg (95KB - 105 downloads)
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RogerK
Posted 5/25/2009 4:15 PM (#44215 - in reply to #44209)
Subject: RE: 1/3 sidecar weight rule


thanks for the picture, would you happen to have a picture of how you mounted it to the Intruder?
thanks,
Roger
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crawf
Posted 6/7/2009 11:27 PM (#44510 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule



Posts: 344
Location: smithville ontario canada
this is an informative thread, good info, thanks gang, cheers crawf.
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hal77079
Posted 6/25/2009 11:34 AM (#44851 - in reply to #1035)
Subject: RE: 1/3 sidecar weight rule


The 1/3 sidecar weight rule - and also the standing on the left footrest while lifting up on the right handlebar and pushing down on the left handlebar and swinginging your weight outwards away from the bike as you do so were all part of the USCA suggestions for the very first organized sidecar training classes developed by and taught by the USCA sidecar schools in Chicago back in the mid 1970s, and were part of the sidecar manuals developed by Hal Kendall and still available for just downloading them.

But we did not originate the 1/3 rule. They are part of the sidecar development articles published in the british motorcycle magazines of the mid 1950s. And should you go back even further, they were in public domain by authors in the 19302 and even the 1920s.

The rule is a general commonsense rule. It was based on many driving experiences. Some have tried to make it very complex. It is a drive it and see. For most applications. But if you have a 250 pound momma on the pillion with a 300 pound dadda on a 350 cc Royal Enfield with an American Eagle sidecar - they will probably not even make the first right hander. This is where the standing on the left footpeg rule will show the unworthiness of the rig.

In the late 70s and early 80s when I attended most USCA rallies, many would come up to me and ask me to try their rig out. The first thing I would do is the left footpeg guideline. If their rig rose suddenly in the air - I would not attempt to drive. Too dangerous for me. Put enough ballast in it so that it behaved more normally then perhaps. But ballast alone will not do it. A light chair with ballast on a heavy bike will put undue stress on the flimsy wheel, spokes, bearings, frame and struts. It all must balance.

A good example is given by our Canadian friend - Bruce - who had a GW1800 with a wraparound british frame - a solid rig. But it took the filling of the entire frame with lead shot, plus a substantial lead sheet under the sidecar body to offset his 350 pound weight. Even so he could still lift the rig on sharp righthanders.

Note - there is a BIG difference between lifting the sidecar wheel on aggressive righthanders and flying the rig. True flying is when the sidecar has been lifted so high that the center of gravity now lies directly over the line between the front and the rear wheels of the bike so that the rig behaves as a lopsided single track machine in a manner similar to a solo bike. This type of driving is usually left to the circus or for parades covered by a police permit. Like stoppies and wheelies, it is banned from normal public street drining.

Lifting the sidecar wheel on the other hand is normal and typical although some sidecarists have been given tickets for dangerous driving - most of which have been beaten if taken to court.
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