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LBS-Sidecars USA | A Preview | LBS + URAL Kit for the BMW GS

Discussion in 'Hack Vendors' started by LBS-USA, Jul 16, 2020.

  1. davebig

    davebig Another Angry Hun !

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    twintwin had a go when he installed LL on his 1150 it wasn't easy, it's on one of his threads about installing them.
    Besides being the poorest guy on this forum I'm also the least educated, I never realized how handy math and geometry where until I hung out in a welding shop.
    The problem with sidecars is it's all subjective one mans perfect was another mans horrible.
    The Bills over at HP where allot more straightforward made drawings kept records etc nice guys .

    Since we're way off the beaten path here, the LBS Ural conversion is very nice Mikepa nothing minimalist about that sub frame and mounting hardware.
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  2. DRONE

    DRONE Dog Chauffeur

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    Shouldn't this entire discussion be moved to the 44-page thread titled -- Leading Links ??

    And what head angle? Thee is no head angle on a telelever front end. That's the problem.
    #22
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  3. DRONE

    DRONE Dog Chauffeur

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    Oh, OK. Let's see if Mike wants to take a crack at it instead of us keyboard engineers.
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  4. brstar

    brstar Long timer

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    So gaining a little understanding of the BMW front end.
    The equivalent of a head angle is a line drawn between the 2 pivot points.
    But the bottom pivot swings in an arc as it goes up and down.
    Varying the "head angle"
    Therefore the only way to accurately measure it would be with no suspension load at all and probably to a line drawn between the front and rear axles.
    then maybe again with the suspension totally compressed.
    The actually varies according to tire size/pressures.
    Hmmm good luck with that.
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  5. steam powered

    steam powered just a regular punk

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    In all the LBS builds that have been featured, Ad replaces the suspension units with fixed struts. I have always thought that they were to set the ride height. Then at the end of the build the corner weights are probably taken and the suspension units can be specified. Build photos and videos from most European manufacturers show that the is pretty standard practice.

    It is also standard practice with most vehicles to set steering geometry at an operating ride height (with race cars at "half wet", i.e. occupant(s), all fluids and half full of fuel). The steering geometry changes through the suspension travel with most front suspension systems.

    @High Octane That Ad includes at least 4 positions for trail, would tend to suggest that there is no magic number to aim for. The range seems to go from 37 to 45mm from what I have seen.
    #25
  6. claude stanley

    claude stanley Claude

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    Steam powered wrote: "It is also standard practice with most vehicles to set steering geometry at an operating ride height (with race cars at "half wet", i.e. occupant(s), all fluids and half full of fuel). The steering geometry changes through the suspension travel with most front suspension systems."..............Steam powered wrote: That Ad includes at least 4 positions for trail, would tend to suggest that there is no magic number to aim for. The range seems to go from 37 to 45mm from what I have seen.............................Truths. .... We typically have two setting and sometimes three for adjusting trail. The LBS We did had two. Two of ours are for reduced trail and one is for stock trail or close to it. The stock trail setting is to allow the bike to be ridden as a solo if the need presents itself. Yes trail does vary some during suspension movement. That is a given as the steering head angle changes slightly and 'bump' comes into play as well. The whole goal is to reduce steering effort. What feels good for one may not be good for another rider. Once trail gets very low steering 'feel' begins to go away. If a rig actually goes into no or negative trail during suspension movement that is not a good thing IMHO. Yes, font tire diameter does come into play in th eoverall picture. A front end with a 135 will have a different trail figure than the same font end with a 165. Numbers are number but ease of steering and personal feel is THE thing. Study the picture in light of all this and it begins to make sense. I personally . as DB mentioned prefer to not go below 1 1/2" trail. I think Ad runs close to that in one setting and less in another. No problem. BTW The LBS we did had two settings for trail adjustment. One was probably close to that and one was less. No foul whatsoever it is all subjective. ........BTW Watch You Tube of the solo sport bike guys doing high speed wheelies on the interstate....some when they come back down go into a very violent wobble. Why? Many times upon drastic fork compression along with possible rear suspension extension end up with bery little of zero trail for an instant and off she goes. Kind of a ruin your day situation. trail pic.jpg
    #26
  7. claude stanley

    claude stanley Claude

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    Another trail diagram >>>>. Think of the movements of the swingarm as well as the steering head angle during bump and rebound. If ya want to split hairs even steering away from straight ahead changes things slightly which is good for internet discussions but not a huge deal in the real world. We talk about trail which is THE word for motorcycle related discussion but it is so similar to caster on a car in many ways. Never hurts to google 'caster' and read up on that . Yes ride height is important and solid struts are good for setup . trail diagram.jpg
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  8. High Octane

    High Octane Long timer Supporter

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    Claude have you ever found a way to measure steering head angle on a bmw telelever ?
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  9. davebig

    davebig Another Angry Hun !

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    Since DRONE's correct we should be on LL thread, for the new guys trail is not the only consideration , they n how hard or easily they steer tire size has allot to do with it, big tires on LL steer hard at low speed they have a big contact patch.
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  10. rg sw wa.

    rg sw wa. Long timer Supporter

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    Raymond Loewy.
    #30
  11. claude stanley

    claude stanley Claude

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    [
    It can be done but we do not go that route . Strange maybe but it works. If we know what the stock trail is we record that. Then we measure from a reference point on the bike horizontally to the front axle......so, say this measurement is 38".(or whatever)....this tells us the position of the front axle. If the stock trail is say 4" and we want to come up with 2" then we know, with all else being equal to move the front axle forward 2". We also provide a pivit point for the swingarm for stock trail and usually one in between. This is for a leading link. Works very well. Keep in mind that trail is a moving number with bump and rebound taken into consideration. The last thing ya wanta do is get into negative trail as all self cetering is lost. ( Run a rig up an incline and try and coast backward dow it....that is negative trail not a good thing. ).
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  12. claude stanley

    claude stanley Claude

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    BTW,,,Tire diameter changes come into play also.
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  13. PaulRS

    PaulRS Dutch fool

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    RTFM. :lol3

    The manual says for the 11xxGS;
    Trail, 115 mm (4.5")
    Head angle, 62,9 degrees.

    Paul.
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  14. High Octane

    High Octane Long timer Supporter

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    That would be a stock bike but when you convert to LL the steering axis angle will change.

    edit: a EZS LL will change the steering angle. I suppose there are other LL that keep the telelever in the stock neutral position so maybe those would stay at the factory angle.
    #34
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  15. PaulRS

    PaulRS Dutch fool

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    Not necessarily so.
    It's just how the LL is constructed.

    I had an EZS R1100RS years back, don't recall if they changed the angle.
    It was lowered by fitting 14" wheels front and back, coming from 17" F and 18" R.

    Paul.
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  16. DRONE

    DRONE Dog Chauffeur

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    That's interesting. In my R1100GS manual, perhaps it's a U.S. version, it says "Caster angle in normal-load position 111mm". In my R1150GS manual it says "Front wheel caster in normal-load position 115mm." And in my K1200LT manual it says "Castor in normal-load position 108.7mm" (note different spelling).

    As a sidecar dilettante, if I had ever noticed this (I have not) I still would have no idea what the manuals were trying to say. So this is TRAIL?

    By the way, I Googled "castor" before writing this post. Castor is the 2nd brightest star in the constellation Gemini named after a Greek god, the son of Zeus. Castor is also beaver in Spanish and in French.

    American_Beaver.jpg
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  17. PaulRS

    PaulRS Dutch fool

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    My German (works) manual, R1100GS says; Nachlauf 115 mm in Normallage.
    My English version of the works manual for the 1150GS says; caster angle 115 mm in normal load.

    Normallage and normal load meaning weight on wheels.
    Caster/castor and Nachlauf is trail.

    Paul.
    #37
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