How do Paralever/ Duolever work for a better ride?

[dennism]

I can see all the front and rear suspension links and thus understand how it works physically but can anyone explain how this translates into a better ride???

Dennis

[SHIVA]

FROM WIKIPEDIA:

Telelever front fork
The Telelever system was developed by Saxon-Motodd in Britain in the early 1980s. The Telelever is a unique front fork, where the shock absorber is located between and behind the two primary tubes attached to a telelever arm.

This system both lowers unsprung weight as well as decouples wheel placement function of the forks from the shock absorption function - eliminating brake dive and providing superior traction during hard-braking situations. This system improves comfort and stability considerably while providing excellent and sporty handling.

Duolever

In 2003 BMW announced the K 1200 S with a new front suspension. It incorporated a front suspension that appears to be based upon a design by Norman Hossack. BMW recognised this fact but no royalties were paid to Hossack. A lack of interest and money saw the end of the project in Britain. BMW named its new front suspension the Duolever. As of 2007, the Duolever is on the K 1200 S, K 1200 R, K 1200 R Sport and K 1200 GT.

The official BMW Motorrad explanation of the duolever is:

The Duolever front wheel suspension is kinematically regarded as a square joint, in which two trailing links made of forged steel are attached via rolling bearings to the frame. These trailing links, which visually resemble a conventional fork, guide the extremely torsionally rigid wheel carrier made of aluminium permanent mold casting. A central strut, which adjusts the suspension and damping, is linked to the lower of the two trailing links, and rests against the frame.

A trapezoidal shear joint mounted to the control head and the wheel carrier is coupled with the handlebar. This shear joint transmits the steering movements. Thus, the Duolever design in contrast to the telefork does not need sliding and fixed tubes. At the same time, it decouples the steering as well as the damping more consistently than the proven telelever.

The advantage of this front wheel suspension on the motorcycle market at present is its torsional rigidity. The BMW Motorrad Duolever front wheel suspension is not influenced by negative forces in the same manner as a conventional telefork whose fixed and take-off tubes twist laterally as well as longitudinally during jounce/rebound and steering. Its two trailing links absorb the forces resulting from the jounce/rebound and keep the wheel carrier stable. Thus, any torsioning is excluded and the front wheel suspension is very precise. The steering commands of the rider are converted directly and the feedback from the front wheel is transparent in all driving conditions.

A kinematical anti-dive effect is additionally achieved, just as for the Telelever, due to he arrangement of the trailing link bearings. While a conventional telefork during strong braking manoeuvres jounces heavily or locks, the Duolever still has sufficient spring travel remaining in this situation and therefore the rider can still brake into the corner extremely late yet directionally stable.

The obstacle-avoidance manoeuvre of the front wheel when riding over uneven surfaces can be converted with the Duolever similar to the behaviour of a telefork. In connection with the low unsprung masses and the small breakaway forces of the system, this results in more sensitive and comfortable response characteristics.

[jw]

http://www.carbibles.com/suspension_bible_bikes.html

[FreedomRider]

What REALLY frosts my jock is how every motorcycle publication will invariably whine that either the Telelever or Duolever feels "vague" in respect to front wheel "feedback".
If having my arms and shoulders pounded into spooge while braking as I descend "Bunker Hill' in downtown LA on the chronically torn up "Grand Avenue" is "feedback" I'll happily waive this esoteric nuance.

I've thoroughly battle tested Telelever and Duolever as well as the popular Howitzer sized Inverts' on my old 2000 R1. The R1's Inverts' come in 3rd place.

[rodders]

I have to agree with you on this, doesn't feel vague to me, in fact I am very confident of the handling of my k12 and I've only done just over a thousand miles on it.

[Uberman]

Okay...it somewhat get the mechanical dynamics, but which is better? Duolever or Telelever? I am torn between the R1200RT and the K1200GT. Is one better than the other or are they the same on different frames?

Uberman

[gandy]

Being an ex BMW tech guy and now Merc here is my take on it.

PRALEVER/SHAFT DRIVE

The function of the Paralever is to prevent the rear suspension being affected by the torque reaction of the shaft drive system.
A conventional mono-lever shaft drive raises the rear of the bike (extends the suspension) when you accelerate snd lowers it when you decelerate (compresses the suspension).

The Paralever system reduces the amount of rotation that the drive hub is subject to keeping it closer to parallel to the ground.


TELELEVER

BMW's front suspension system, Telelever, is the single most argued and debated front suspension ever. It sperates shock absorption and wheel/steering control.

A swingarm connects the fork tubes (which move up and down but provide no spring or damping action), to the frame and a shock absorber unit sitting behind the forks.
This shock absorber provides the damping and spring actions , like a rear shock would do.

As the forks compress (shorten under load) the swingarm rises and pushes the forks forward slightly, increasing the trail and caster angles ( it can do this because the top of the fork tubes are connected to the frame via the ball joint).

This then means the bike, becomes more stable on the way into corners unlike a conventional telscopic fork set up where the trail and caster angles decrese for the the bike to push wide ( horrible feeling if you have experienced this on a normal bike lol )

The angle of the Telelever also gives the bike a degree of anti-dive, so the shock absorption function is not all used up during progressive and heavy braking.

DUOLEVER IS AS SHIVA EXPLAINS

[FreedomRider]

Okay...it somewhat get the mechanical dynamics, but which is better? Duolever or Telelever? I am torn between the R1200RT and the K1200GT. Is one better than the other or are they the same on different frames?

Uberman

in respects to "Telelever" see link below

http://www.dinamoto.it/DINAMOTO/on-line ... lever.html

The Saxon-Motodd (Telelever) though far superior both geometrically as well as resisting torsional forces when compared to conventional telescopic forks still effectively "shortens" the bikes wheelbase as it compresses.

The Hossack "Duolever" design effectively produces NO change in the bikes wheelbase during its compression & rebound, thus making a more "neutral" handling motorcycle at all times.

http://www.bmwsuperbikes.com/Images/epi ... s_l_01.gif

[Uberman]

Okay. So basically...please bear with me...the telelever's wheel base will adjust as you corner making it more stable than most, but not as stable as the Duolever. Is that correct? If so, then that makes the Duolever a better system, right? The RT is supposed to be better at lower speed turns and the GT better at higher speed turns, correct? Please continue to enlighten me. I love the look of the RT but also love the power of the GT. Thanks again.

Uberman

[FreedomRider]

Okay. So basically...please bear with me...the telelever's wheel base will adjust as you corner making it more stable than most, but not as stable as the Duolever. Is that correct? If so, then that makes the Duolever a better system, right? The RT is supposed to be better at lower speed turns and the GT better at higher speed turns, correct? Please continue to enlighten me. I love the look of the RT but also love the power of the GT. Thanks again.

Uberman

You basically got it.

The respective strengths between the RT & GT are probably due to wheelbase differences.
The RT's wheelbase is 58 inches as compared to the GT's 62 inches.
A longer wheelbase is commonly more "stable" at high speeds
A shorter wheelbase is quicker reacting thus lighter feeling in tight, lower speed corners.

"Rake" and "trail" also demonstrably effect overall handling of a bike.

[Uberman]

Okay. Thanks. Looks like its going to come down to the ride itself. I will just have to see if I can tell the difference.

Uberman.

[iehawk]

What REALLY frosts my jock is how every motorcycle publication will invariably whine that either the Telelever or Duolever feels "vague" in respect to front wheel "feedback".
If having my arms and shoulders pounded into spooge while braking as I descend "Bunker Hill' in downtown LA on the chronically torn up "Grand Avenue" is "feedback" I'll happily waive this esoteric nuance.

I've thoroughly battle tested Telelever and Duolever as well as the popular Howitzer sized Inverts' on my old 2000 R1. The R1's Inverts' come in 3rd place.

The way I explain it to my clients.. is that on regular bikes, you're used being screamed and yelled at by that front suspension, "HEY WE'RE BRAKING! HOLD ON TIGHT!". While on the K bikes, it's more of a whisper... "psst, by the way, we're braking."

There is feedback. Maybe not at 9/10 or 10/10 (since I don't ride even close to that level), but for most of us mortals, it's plenty. And I do like the fact that it's so stable to brake into corners, way deep, late engage and late release. I love it.

[k1300rbrazil]

Iehawk,

I think you balanced the whole discussion perfectly. In my opinion those systems are safer (and even more comfortable) then conventional forks to mortal individuals like me... But when it comes to high performance, nothing compares to the old yet simple conventional systems, as we can see in superbikes and moto gp world championships. Like we say in Brazil, there must be honey some where to see so many bees licking them...

Rafa.

[edeslaur]

All those great posts and nothing on the significantly reduced amount of stiction from either x-lever over regular forks.

I've ridden both Rs and Ks. My last bike was an R1100S, before than a first-gen K1200RS. The K-S handles much better than the KRS, but not as good as the R1100S. Wheelbase is most of it, but the R1100S did give me more confidence when being a hooligan. I sold the R because I'd have the poor thing wrung out and I could use more power. The chassis was so good, it was underserved by the motor and frustrating to ride in fast stuff/company.

The K1300S seemed to have better feel, and does have different front end geometry/parts than the K1200S. I believe the KGT also has changed between the two models.

One other real difference between the KGT and RT is the wind protection. I found the KGT to have too much on a warm day. In my mesh jacket at 60, I felt like I was standing in the parking lot with the sun shining and no wind blowing. Be great in the winter.

Even the RT is more than *I* want (my dealer loans out RTPs), hence my tendancy towards S-bikes.

And don't forget maintenance costs. The Rs have a big maintenance at 20-some K (IIRC) and my R-S cost me a boatload more than my K-S for that maintenance, probably the same over the long run, though I did much more of my R-S maintenance (no more warranty and I suck at tracking paperwork).

[davenjohn]

Mine worked pretty well at -23Celsius on winter 2008

Alot of Fun!!

[iehawk]

Duh. Almost forgot one thing.

I did get to ride a 2008 R1200R for about 2 weeks before. It must be the best of the boxer bike; not too lean forward like the S, not too high (and turn in quicker) than the GS, and almost 100 lbs lighter than the RT (more nimble).

Taking it to the twisties, I found it really easy to get used to and to go fast. But I also found the front gets light if you throttle out of a corner too fast... a problem I never have with the K1200R.

The Duolever does feel stiffer, probably why it's a bit ' heavier' feel, although I still feel it's light enough. I think of it like the weighted steering in a sports car, feels very stable and easy to hold the line.

[throttlemeister]

Iehawk,

I think you balanced the whole discussion perfectly. In my opinion those systems are safer (and even more comfortable) then conventional forks to mortal individuals like me... But when it comes to high performance, nothing compares to the old yet simple conventional systems, as we can see in superbikes and moto gp world championships. Like we say in Brazil, there must be honey some where to see so many bees licking them...

Rafa.

I don't agree. It does not work better. But, the biggest drawback of Telelever/Duolever is weight. In a place where every ounce matters, you do not want to have a front fork system that weighs 2-3 times as much as a conventional fork, and a lot of it is unsprung weight at that. The handling advantages just don't weigh up to the weight advantages of a regular fork (no pun intended).

As far as feedback, it IS more disconnected, just like the rear shock is more disconnected than a regular front fork. With a conventional fork, you are basically grabbing the top end of the stanchions which is the same as grabbing the axle. Every little movement of the wheel can be felt. Since with Telelever/Duolever, the steering and suspension are decoupled, what you feel in your handlebars is much more damped and more subtle than most people are used to. It is not like it is not there, but especially journos spend so much time on conventional bikes and rarely enough time to really get in tune with a bike they just have a problem feeling it.

[Mirage_ZA]

Iehawk,

I think you balanced the whole discussion perfectly. In my opinion those systems are safer (and even more comfortable) then conventional forks to mortal individuals like me... But when it comes to high performance, nothing compares to the old yet simple conventional systems, as we can see in superbikes and moto gp world championships. Like we say in Brazil, there must be honey some where to see so many bees licking them...

Rafa.

I don't agree. It does not work better. But, the biggest drawback of Telelever/Duolever is weight. In a place where every ounce matters, you do not want to have a front fork system that weighs 2-3 times as much as a conventional fork, and a lot of it is unsprung weight at that. The handling advantages just don't weigh up to the weight advantages of a regular fork (no pun intended).

As far as feedback, it IS more disconnected, just like the rear shock is more disconnected than a regular front fork. With a conventional fork, you are basically grabbing the top end of the stanchions which is the same as grabbing the axle. Every little movement of the wheel can be felt. Since with Telelever/Duolever, the steering and suspension are decoupled, what you feel in your handlebars is much more damped and more subtle than most people are used to. It is not like it is not there, but especially journos spend so much time on conventional bikes and rarely enough time to really get in tune with a bike they just have a problem feeling it.

It's not just the weight - you must look at it dynamically.
When you brake hard on the track, with conventional fork your steering geometry changes and bike turns faster than normal. So you can brake later, carry more speed longer and square off the corner faster.
I love Tele/Duolever and I have learned to trust it. I have been in situations where front was about to wash out, on moderate lean angles with cold racing tyres (I was going to write proper post about it) and there was very little warning, all of the sudden bars started to shake. For racers, it is more important to "feel" when grip is there. For us, mere mortals, it's good to know that grip "is" there.

[iehawk]

It's not just the weight - you must look at it dynamically.
When you brake hard on the track, with conventional fork your steering geometry changes and bike turns faster than normal. So you can brake later, carry more speed longer and square off the corner faster.
I love Tele/Duolever and I have learned to trust it. I have been in situations where front was about to wash out, on moderate lean angles with cold racing tyres (I was going to write proper post about it) and there was very little warning, all of the sudden bars started to shake. For racers, it is more important to "feel" when grip is there. For us, mere mortals, it's good to know that grip "is" there.

Exactly.

The K bike is also designed from the beginning to be balanced front to rear at where you sit (50/50). One reason why it feels very solid and smaller once it's going. It is out performing the Hayabusa (old bike I understand) and the Kawasaki ZX14 (ZZR14 in Europe?) in terms of handling.

There's a reason why BMW lightened up the Duolever moving from K1200S/R/GT to the K1300S/R/GT. It feels noticeably better. It was the reason I picked the K1200R, coming with the most aggressive geometry (fastest steering of the trio). The K1300S feels lighter and quicker than K1200S, but still not as 'light' as the K1200R.

When you have learnt to trust the system, it's pretty amazing what you can do on it. As I said before, it works great within the mortal skills, but probably not when you are at the higher level (magazines would call it riding at 80%, 90%, 100%, etc). I have no experience there, since I'm not there.

When I was learning on the track for the first time on my K12R, I was able to brake deeper, farther, later than those on sportsbikes. By the second half of the sessions I was constantly passing coming out of the turns.

I started to pay attention to other's braking and accelerating point and noticed that I was also able to accelerate earlier. I can brake, start turning, then gradually release the brake, and get on the throttle... not having to upset the steering geometry much. And with the longer wheelbase, I didn't have to deal with power wheelie out either.

On the S1000RR, same track a year later, I realized that suddenly I had to learn to deal with the front suspension a bit more, since there's suddenly more things to pay attention to that I didn't have to on the K12R.

This is what I meant by the Duolever still 'talks' to you, it's just not as loud. If you are used to be 'yelled' at, you will have problem 'listening' to anything quieter, but as you get used to it, it's great. It doesn't overwhelm you with too much information. When you don't have to concentrate as much on one thing, it means you can divert that attention to other things. Riding on the street, this means you can pay more attention to the traffic and your surroundings.

I think they should have an international race class for the bigger bikes, maybe a short endurance class for 1400cc... that should be very interesting to watch.

[throttlemeister]

No offense, but your statements re K1200R are wrong. The K1200R has exactly the same chassis, steering, rake, trail, etc as the K1200S. It handles exactly the same, except for the riding position and higher and wider bars which make it feel significantly easier to flick around than the S models. You can check the part numbers on realoem.com. All the significant part no's are identical between the K1200S and K1200R.

The K1300S has a different lower Duolever triangle, which makes it handle significantly better.

[iehawk]

No offense, but your statements re K1200R are wrong. The K1200R has exactly the same chassis, steering, rake, trail, etc as the K1200S. It handles exactly the same, except for the riding position and higher and wider bars which make it feel significantly easier to flick around than the S models. You can check the part numbers on realoem.com. All the significant part no's are identical between the K1200S and K1200R.

The K1300S has a different lower Duolever triangle, which makes it handle significantly better.

Really now? They definitely feel very different to ride to me.

Added: There is a noticeable riding difference between the K1200R and K1200S... beyond the riding position. I'll have to dig into my old job's box to find the specs for both bikes, but here's what I've found in the trusty old internet:

http://www.motorcyclistonline.com/roadt ... index.html
BMW K1200R
Extreme makeover? Reality TV's got nothin' on BMW, which stripped its nastiest autobahn-burner and ended up with a 160-mph, do-everything naked bike
From the February, 2009 issue of Motorcyclist
By Roland Brown
Photography by Double Red

9th paragraph after the bold intro and 2 lines:

BMW retained the S-model's aluminum frame, with a slightly modified Hossack-style Duolever fork that places the legs a half-degree steeper, with 11mm less trail than the S for, BMW says, an improvement in maneuverability. Like the K1200S, the R comes with BMW's optional and innovative Electronic Suspension Adjustment (ESA) and ABS for its triple-disc brake system.

I know that the K1200R's is 0.4 inches longer (62.2 inches) than the K1200S and k1200GT (61.8 inches). And having ridden both bikes extensively before (also the 2009 K1300S), I know that the K1200R turns in the easiest, followed by the K1300S (with the lighter Duolever material), and then the K1200S. I figured the added weight on the front part of the bike contributes to this (fairings, headlights, etc).

I'm not here to debate the facts like two kids comparing whose toy is the best. I'm not talking based on what I've read, but based on what I've experienced on both bikes. Maybe you're right, maybe I am?

[Major_Trouble]

Basically the Duolever is great on the road where changable condition are the norm. The decreased feel doesn't mean the grip isn't there it's just not communicated as directly as conventional forks. The fact that the suspension still has supple travel and lack of dive when braking is it's main advantage. The K1300 may be a heavy bike but with Duolever, long wheelbase and ABS it's the fastest stopping road bike there is. Just compare it to a ZZR14, Busa or even an ABS equiped Fireblade.

Forks are better on the track for racers when they can dial in the suspension settings for a circuit and have great feel and they have the ability to change rake and trail by breaking into the corner, compressing the forks, to get the bike tipped in quicker. It's all good on the smooth race track but not such an advantage on the road where things are a little less racy.

K1300 = Duolever = road bike, S1000 = forks = track bike.

BMW have their reasons and have used what they believe to be the best for each environment.

[cburgess594]

Got this one... http://www.k-bikes.com/forums/showthread.php?t=1014

[Ivan996]

To be honest I can't tell much difference between a conventional fork and dualoever (K1200R). They both dive a bit under hard braking, they both stand up slightly when braking into a turn, both countersteer normally, and both seem to absorb bumps much better when up and down versus full lean.

I did notice, however, that the steering stem of my KR is significantly behind where a normal steering stem is. Indeed, if one where to extend the steering stem line on the KR then it would go right through the top of the cylinders. I don't know if this is a good or a bad thing but it certainly is different and I do feel I'm a bit too far behind the front wheel compared to a normal bike...it's somewhat like driving one of those really long front-engined sportscars.