Telelever Duolever system

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Taffy
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Telelever Duolever system

Post by Taffy »

maybe a winter chat - but then it is too late isn't it?

been looking at alternative sources of front suspension and steering (note they are separate here!) over recent weeks and the only simple system I see that could really challenge the leading links is this:

the Duolever system invented by none other than Norman Hossack who i used to race with (road racing). BMW waited for his patent to run out before changing from Telelever to Duolever.

It's simple, strong and separates suspension from steering

if anyone is any good at putting up photos directly instead of links please help!

http://www.hossack-design.co.uk/php/page.php?p=4#c2

http://www.dinamoto.it/dinamoto/8_on-li ... r_eng.html

the advantage seems to be
strength and lack of flexure
the two spindle holds don't 'walk/flex'
a big one is the lack of momentum/swing caused by the pivot and arms behind the wheels
suspension is totally separate from steering
looks relatively as cheap as a leading link
brakes and wheels can be fitted as normal.
rear shock technology can be used.

unsprung weight looks about the same if the lower legs just cleared the top of the tyres and were solidly connected.
trail and offset could be changed with an eccentric front wheel spindle

I remember asking I think it was NB a few seasons ago how telescopic forks were doing and he more or less said: "after they have spat all the oil out (straightaway) past the seals they still OK without any in them, they bind a little as well". so I imagine something like this would be an improvement surely?

there are other far more complicated types but the unsprung weight is poor. this system looks good though...

anyone seen anything like it being run?

Taffy
Last edited by Taffy on Tue Sep 10, 2013 10:11 pm, edited 2 times in total.
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AthurWalton
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Re: telelever system

Post by AthurWalton »

Looks very similar to a pre war girder fork,which was favoured by some sidecar racers into the 1950s because they didn't flex as much as telescopic forks of the time. A lot of unsprung weight though as the whole fork assembly moves up and down.
Grant L Peacock
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Re: telelever system

Post by Grant L Peacock »

Hi,

As an ex-sidecar driver and an engineer anything different and or new in the racing world is interesting to me.

I would be happy to talk with you more if you were interested in developing this system for sidecarcross as I have CNC machining facilities of my own

GLP PRECISION.
E-Mail grant.peacock@btinternet.com

If I could be of any help to you in this potential project don't hesitate to contact me.

Cheers

Grant
Doogle
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Re: telelever system

Post by Doogle »

The factory BMW Dakar bikes used WP telescopic forks not the telelever system.
Dont know why, but there must have been a reason?
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Barry
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Re: telelever system

Post by Barry »

Taffy
When completing my HNC project at college back in 1994 I designed and built a frame with this design. I never quite finish it due to kids and money, but I have all the plans still. I have ran the system through a stress calculation software and there are a number of potential benefits to cornering/braking. I have a design on the sidecar wheel linkage to improve right hand corner speed as well. At the time I had a 620 zabel 1992 engine that I based the frame round. When I was completing my HNC, I was sponored by a design engineer from Lotus and about 10 years after I left college this system was put on a downhill mountain bike by two ex Lotus engineers and was in mountain bike uk mag. The benefits on a solo are none due to the unsprung weight, but I think it would work well on a sidecar in combination with some other figures.

Jesse
Taffy
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Re: Telelever/Hossack steering system

Post by Taffy »

Grant L Peacock wrote:Hi,

As an ex-sidecar driver and an engineer anything different and or new in the racing world is interesting to me.

I would be happy to talk with you more if you were interested in developing this system for sidecarcross as I have CNC machining facilities of my own

GLP PRECISION.
E-Mail grant.peacock@btinternet.com

If I could be of any help to you in this potential project don't hesitate to contact me.

Cheers

Grant
that's some offer! perhaps to design and make the front system and see if Kev Hollister wants to try and convert a chassis offered, to pick up and run with it if it works - or yourself of course. a GB headstart... it would be great if the UK made chassis again and had a lead on the continent (even if short lived I guess).

anon
I've re-read some more detail and the top spherical joint can be made adjustable forwards or back and therefore change the rake as well. this would not alter the position of the handle bars either!

the bottom wishbone can be brought down just over the tyre for massive strength. the 'tuning fork' wheel mount would be identical to a bicycle with an arm each side of the wheel meeting just above the tyre at a ball joint or spherical bearing.

it might be possible to have an oval CSA to the right leg for the brake and then oval it laterally on the left lag to offer support when cornering?

a disadvantage of the Hossack system is that the single shock is laying roughly where the frame backbone is on all single spine outfits. BMW though squeezes the shock into the steering head area and if here, the shock needs to be short. I did a special quad two years ago. a Cannondale engine was removed and a 666 longstroke Husaberg fitted and the shortest shock ever needed to be fitted. the shortest you can buy is for the Ducati air cooled (cantilever) bikes...... :-D

with the Hossack and BMW system the shock is placed high up. but.... there is also a 30 year old design by a John Wright-Bailey that uses the bottom strut mount as the middle of a see-saw so that the shock on the other end goes down the front of the frame. this keeps the CoG really low and means that with a single shock you saved weight as well.

they deliberately don't let you see the steering system on the Hossack so I'll explain.
The Hossack system
a bicycle type solid fork that holds a conventional wheel and brake system.
above it is a pivot joint on the end of a triangular shaped wishbone mounted on the bike's main frame to the left and right creating a triangle.
there is another wishbone above it (same again)
above all this is a solid plate to mount the handlebars directly onto the chassis.
the steering is done via two 'H' shaped hinged plates. the first 'H' turns with the handlebars under the top plate. the other 'H' is connected to the stem of the steering off the front wheel. then the two 'H's are hinge joined at the tips at about 45d angle and you have direct steering with no bump steer.
that means no jolt through to the bars at all. none!
so rider comfort is improved although maybe their might be a lack of trust and feel in what is happening underneath!

anon
having been brought up on solos and their suspension we're taught to look and feel from early on for 'balance'. balance when the suspension deflects so the whole bike sits well. if you have a harsh front and soft rear the bike doesn't ride well.

as I see it the problem with a leading-link outfit is that the rear wheel is on a 650mm long pivot and the front on a 350mm pivot. when you G-out the front wheel spends its second half of travel folding back into the bike. the wheel base shortens considerably, the more weight that goes on the front, the more that goes on!

at the moment with L-L the bottom steering bearing is way above the tyre to allow suspension travel. with this system the bottom joint is always 15mm over the tyre.

BTW girder forks carried the suspension and then turned with them, this added to steering inertia. with the Hossack system the suspension isn't carried.

a sidecar would appear to have 'some' spare room compared to a solo to carry out these ideas.

Taffy
I don't want a works bike I just want their address book! :?: :?:
here is a link to the SMCA web site for ya! http://smcagb.moonfruit.com/ :-D
Taffy
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Re: Telelever Duolever system

Post by Taffy »

thought I'd share these images with you:
these first two images are my favourites and belong to a Sidecar Roadracer from around 1970-1975 from what I can make out named John Wright-Bailey.

The John Wright-Bailey system
Image
I wouldn't have 4 arms going to the equivalent of the headstock tube...far too weak. better to have wishbones/struts or as I prefer to call them: 'A' frames. these would berock solid and the "headstock" would have a spherical bearing top and bottom.

he's used a linkage steering system but I think the 'double H' could be simpler. looking at the position of the linkages he just has to have a whole bunch of bump steer. so the diagram is for demonstration purposes only as they used to say.

here is what they put on the old Elf Racers.
Image

continued...
I like the bottom A-frame also acting as a bell-crank and allows the shock to be located low like the present L-L pair. however there is no shock/travel ratio, so it's no different to rear shocks from the era 1936-1972. it needs a little rising rate building into it or an angled shock at the minimum like KTMs solos have. I guess when JW-B did all this though The Three Degrees were number 1 so let's forgive him for the lack of rising!

I don't believe a linkage steering arm is right but a form of steering with a ratio that means the handlebars don't travel as far as the wheel is needed. can rider's get used to that?

there is now a plethora of steering systems to be tried nowadays using hydraulics. I'm thinking that the only way to avoid bump-steer is for the hydraulic arm to be located at the lower A-frame pivot on the frame and the end of the arm would have to be on the lower yoke in the same plain (plane?) as the spherical bearing. this way there is no deviation over the suspension travel. I guess the steering 'link' would be on the left in the UK, right for europe.


Below
here, it is a lot clearer what he's thinking. he has the shock mounted off the back of the top pivot but the bottom one would be better all the way round. low centre of gravity being one.
Image
other obvious stuff: sidecars need round tubes even more than solos so, suddenly a nice pair of chromium steel 50mm lower inner fork legs straight off a MX bike, locked into what is called a 'bridle rod' front end with a steering stem looks better. this is a bicycle front end but you get the picture
Image

no need for the fork legs to be wide to the top yoke, they aren't under the stress of the bottom yoke, so they can move in towards the top spherical bearing. the top yoke can be over the top A frame with the spherical bearing in between.

to me the John Wright Bailey system is near, my system is better.
with independently adjustable A frames we can:
change the rake independently, while keeping the same wheelbase
change the wheelbase at the front as you can do at the rear SA adding a chain link etc. this allows the weight balance to be shifted back or forth and this means you can change the weight distribution independently.
you can change the action of the wheel - deflection if you like - if you have adjustable pivots for the A frame.
if you take for instance; KTM legs-and use an eccentric spindle you can now adjust the trail

holding each side of the wheel in a strong brace over and near the tyre is the nearest place you can if using this system. the strength is going to be excellent. it should be lighter than L-L and there's NO 'pendulem effect' (the leading links weight swinging behind the wheel) with this - unlike L-L.

dive and anti-dive can be done here just like a solo by adjusting the A-frame pivots up or down.

the last big thing is that unlike the last third of L-L travel which sees the wheel going backwards INTO THE BIKE, this keeps going up and up not up and back. because you may have come over a jump and have throttle off I've seen teams pitched out the front. this would stop this, this alone in one place once per lap could be worth its weight etc etc.

The MaKagen system
Image
Really, this is a good idea and yet he did it for solos!! a wider pivot on the frame and it would be quite solid. I'd have gone for a spherical bearing top and bottom in a pair of 'A' frames into a headstock but like this, it looks ready to have link steering or to put the handlebars back on and go up 'n down like a fiddler's elbow! yee-haw anybody? let's just say he had a go.

here's BMW's Telelever
Image
as I see it rigidity is its big point. doesn't save any weight really but by god it ain't gonna bend is it! you can't alter the trail (back and forward) or the rake (angle) easily. or if you imagine you could you can't alter one without the other very much. and the handlebars move with the shocks so you feel some sort of 'bump steer'. for the doomsayers the argument is won when the shock has to be up near the headstock.


The ideal front end?
a pair of upside down forks, take the chromium inner lower halves. keep the caliper mount, infact keep the lower front from a solo; 'lock, stock' and fit.

just over the tyre have them enter a bottom yoke. mudguards must be fitted in two halves to the front and back face of the yoke.

the lower headrace bearing would be a spherical and mounted under an A frame not on top.

as the fork tubes run above the lower yoke they get a lot smaller as no need to be so big and strong. they thin down via a taper before straightening into a top yoke. this allows 10mm of up and down adjustment for bike ride height etc. the other alternative is that the bottom yoke is strengthened and triangulated in and up towards the top mount and has again two vertical thumbs each side of the top spherical. this is then a very narrow top yoke. 3" maybe. so you still raise and lower the 'fork legs' for ride height etc just like a solo. all this to save a few grammes... maybe. so let's call that the Mk12.

the top spherical bearing would also be in an A frame but this time the A frame would be under the spherical bearing and the yoke on top.

the bridle rod system (just think of your bicycle fork with the shaft through the headstock - rather like a tuning fork and then a linkage to steer) has a shaft from the bottom yoke to the top and this can be left naked in the middle unlike our present headstock. then on the shaft we mount the steering which may be the H-H but I'd rather have hydraulic.

here is the BMW duolever system:
Image
it doesn't need a lot of suspension travel so those arms are very short.

the sidecar chassis should be Ducati open trellis type rather than single spine as now at the front to allow the two A frames to mount. that is a real solo thing where all the stresses are in a straight line one way along the line of the chassis.

see below for that wide front. off my TT2 chassis BTW.
Image


as for the shock and how it would work? well a straight rocking arm and shock is "out". we need better than 1936-1972 da javu etc. so a rocker system needs incorporating or an angled shock > KTM and their PDS system.

the A frames would run parallel at the pivot so that rake and trail can be adjusted. even wheelbase/weight distribution.

the disadvantage of all these systems is the lack of balance front to rear in that the front till now with L-L has only had a nice 5-6" of travel before the wheel heads back into the bike.

My system and the JW-B system will have excellent geometry and at least the same travel. it depends how long those A frames can be and strength maintained. On a car the suspension forces are lateral to the A-frame as are the brakes but the cornering forces are through the system. with the same system on a sidecarX the steering forces are lateral and the suspension and braking forces are the ones that are in line. I think we get the better deal myself.

Taffy

footnote
Image

a frame with width! the 2014 EML with a twin spar system linking the headstock almost directly to the swing-arm pivot (shame it doesn't) which the WSP does. the slightly broader chest on the front of the frame means that the ideas detailed above become ever more feasable. however, with the new stiffness: what will happen if the frame is now too rigid? will riders want to go back or deal with the front end?
Last edited by Taffy on Tue Oct 08, 2013 10:13 pm, edited 3 times in total.
I don't want a works bike I just want their address book! :?: :?:
here is a link to the SMCA web site for ya! http://smcagb.moonfruit.com/ :-D
Taffy
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Re: Telelever Duolever system

Post by Taffy »

Image

note the way in 1943-1947 Northern Irishman Rex McCandless made the forces go through the headstock. the opposite of EML. EML have then put tons of bracing in that works in line astern. but would a 66 year old design have been better?

Image
this is the first ever safety bicycle 'we' made in about 1843. it has a bridle rod steering system.

I reckon in 20 years time we'll be back there. if we delay it 10 more years we can bring out the bridle rod design 200 years to the day after the safety bicycle was invented! :lough: :lough: :lough:

regards

Taffy
I don't want a works bike I just want their address book! :?: :?:
here is a link to the SMCA web site for ya! http://smcagb.moonfruit.com/ :-D
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