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Trailing link is very interesting and certainly not dead. A search shows up quite a bit of stuff including scooters, top notch mountain bikes. Far more on leading link though, especially from motocross. Fascinating stuff. It is really pretty amazing that telescopic has maintained it's position. Despite the challenges it presents it is still what makes bikes feel like what we are used to.
 
and that was a borrowed bike, I saw it at Moto Di Marino in Sussex when it came out of the owners van prior to pre-repair appraisal, since the Millar museum were going to do the repairs in house, and the owner wanted surety of the damage before it got repaired, and then to be checked afterwards as well.
CLEM

I told everyone that leading links as the Guzzi V8 is the way to go
 

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Wasp moto cross sidecars were originally trailing link,Rob Rhind-Tutt was a great believer. I used to set my leading links up with the link lower than the front spindle ,allowing for it to move back as it hit bumps.
Back in ?84 when I was a student at Merton, I was setting up our stand at the Earl?s Court Show when Sammy Miller asked me to help him get a bike out of his van. I hopped in the van, Sammy got the back and I wheeled Ray Amms ?Silver Fish? lay down Manx Norton kneeler into the hall onto a plinth. Can?t imagine many sixteen year olds being trusted with it now.
 
I think Sammy Miller has it all wrong. All of the suspensions he demonstrated have similar wheel movement over bumps. In all cases the wheel moves back as the suspension compresses.

There's a reason trailing link front suspensions never caught on: A trailing link is actually less compliant than the others because the path the wheel takes changes to a more vertical movement as the suspension compresses. If you wanna go with linkages, a properly set up leading link is a better solution.

The "tests" he conducted by wheeling the various bikes over a brick were meaningless. The bikes had no rider on them so none of the suspensions were under normal load. Of course they'd bounce over the brick under such conditions. I reckon the only reason the trailing link one looked a little less bouncy was because it was woefully under-sprung, and probably had the friction dampers backed off.

While the bikes were interesting to compare, I think Sammy has done some damage to his credibility by making such idiotic "tests" and dumb comments about their suspensions. He should have just shown the different mechanisms and left it at that.

His demonstration of the difference between leading and trailing link using the wheelbarrow was completely fatuous.

I met Sammy at his museum in 2009. We chatted for quite a while. He's a really nice guy. I told him I was from Australia and that visiting his museum was one of the highlights of my trip to UK, and as I'd be unlikely to get back there again I wanted to make the most of my time there. I was ogling the Moto Guzzi 500 V8 at the time, and he asked me if I wanted to sit on it (it had "do not touch" signs all over it). Of course I accepted the invitation. I had a photo of myself sitting on it (with a big grin and probably making vroom vroom noises) but I lost all my photos of that trip when my laptop went belly-up.

Anyway, having met him and knowing that he's a genuinely likeable sort of bloke with a passion for bikes, I found it disappointing to see him making a bit of fool of himself in that video. Especially as he's such a well known and respected member of the motorcycling world.


 
I found it interesting, but I am not an Engineer or play one here. Testing is an important thing but to be accurate and repeatable plus getting meaningful data is way harder than most think. He did have an impressive competitive history riding and at least someone was modifying that Arial Trials bike he rode for decades. At least we got to see him ride that Dust Bin Fairinged bike like he meant it. Bet he has done s few laps of that car park.
 
Dellortoman said:
I think Sammy Miller has it all wrong. All of the suspensions he demonstrated have similar wheel movement over bumps. In all cases the wheel moves back as the suspension compresses.

There's a reason trailing link front suspensions never caught on: A trailing link is actually less compliant than the others because the path the wheel takes changes to a more vertical movement as the suspension compresses. If you wanna go with linkages, a properly set up leading link is a better solution.

The "tests" he conducted by wheeling the various bikes over a brick were meaningless. The bikes had no rider on them so none of the suspensions were under normal load. Of course they'd bounce over the brick under such conditions. I reckon the only reason the trailing link one looked a little less bouncy was because it was woefully under-sprung, and probably had the friction dampers backed off.

While the bikes were interesting to compare, I think Sammy has done some damage to his credibility by making such idiotic "tests" and dumb comments about their suspensions. He should have just shown the different mechanisms and left it at that.

His demonstration of the difference between leading and trailing link using the wheelbarrow was completely fatuous.

I met Sammy at his museum in 2009. We chatted for quite a while. He's a really nice guy. I told him I was from Australia and that visiting his museum was one of the highlights of my trip to UK, and as I'd be unlikely to get back there again I wanted to make the most of my time there. I was ogling the Moto Guzzi 500 V8 at the time, and he asked me if I wanted to sit on it (it had "do not touch" signs all over it). Of course I accepted the invitation. I had a photo of myself sitting on it (with a big grin and probably making vroom vroom noises) but I lost all my photos of that trip when my laptop went belly-up.

Anyway, having met him and knowing that he's a genuinely likeable sort of bloke with a passion for bikes, I found it disappointing to see him making a bit of fool of himself in that video. Especially as he's such a well known and respected member of the motorcycling world.
Click to expand...

You?ve missed the fact that trailing link rides over a bump in the same way as a stylus trails on a record player , leading link the wheel digs in to the bump like lathe tool. In my earlier post I mentioned that I used to lower the leading link pivot lower than the wheel spindle so the wheel can travel slightly back to comply with fast bumps . Pushing the bikes over bumps was just to demonstrate the wheel travel, I think to say Sammy doesn?t understand suspension is a bit daft, BSA, Bultaco & Honda used to pay him to develop trials bikes. Conventional forks on a motorcycle are a bad idea perfected and endure on a motorcycle in the same way as chain drive.
 
Not sure 11 British trials titles, 2 European trails and racing for all the big factory's in circuit racing equals not knowing anything.
Most be easy this motorcycle business 🤔
 
laverdas said:
Not sure 11 British trials titles, 2 European trails and racing for all the big factory's in circuit racing equals not knowing anything.
Most be easy this motorcycle business 🤔
Click to expand...

Haha.
I didn't bother becoming world champion.
I knew it all already.

Paul
 
I agree with some of what Cam says, as the demonstrations don't really show how the different systems work i practice, but it was a very quick introduction he was giving. He could have just as well just bounced them on the front brake. The trailing link has the wheel actually pivoting forward slightly as it goes up doesn't it, as it is a pivoting arm so the wheel follows an arc.
It would be interesting to see if a wheelbarrow bounces less if you are pushing it or pulling it, as the pivot is at the handhold, being either leading or trailing.
That is a nasty shot of him on the 900SS trying to do a clean over those bales, without dabbing his foot, an unusual choice of trials bike.
 
Exmoor beast said:
You?ve missed the fact that trailing link rides over a bump in the same way as a stylus trails on a record player , leading link the wheel digs in to the bump like lathe tool.
Click to expand...

No, I didn't miss that fact, mainly because it isn't a fact at all. It's a fallacy that a trailing link will ride over a bump better than other types of suspension. Perhaps that general belief comes from the wheelbarrow theory that Sammy used as an example. The problem with the wheelbarrow is that it's a poor example. I'll explain below ...

Firstly though, I'll address your analogies of record player and lathe tool.

A record player arm is trailing for an entirely different reason - tracking stability. If the turntable was spun the other way, there would be a much greater likelihood of the needle jumping out of the groove and skittering across the record. It would be like driving a car down the highway with a trailer attached to the front. Incidentally, my previous vehicle had a towbar at the front for manoeuvring trailers about (it's way easier to push a trailer when driving forwards than reversing). I've occasionally thought it would be an interesting challenge to drive down the road with the trailer in front. I reckon it would attract some startled looks from other drivers :D

Your lathe tool analogy is unsuitable too. A cutting tool has relief angles on it that tend to draw it into the material. One of the reasons that metal lathes are built so solidly is to resist such forces. If your lathe tool habitually digs in, then you need to revise the tool shape or cut depth. Or perhaps check for wear in the spindle bearings or tool carriage.

OK, back to suspension ...

For best suspension performance, front wheels need to move backwards a little as they go up over a bump. I won't go into the reason for that unless someone wants an explanation. Let's just accept that for now.

It's obvious how that rearward travel happens with telescopic forks because of the rake angle of the forks.

A trailing link swings in an arc exactly as Tippie described. If the swing arm pivot is above the axle, then the wheel will initially move backward as it rises, but the further the suspension compresses, that backward movement diminishes because the arc of travel curves forward. Taken to an extreme, if the wheel axle moves above the swing arm pivot, then it actually starts to move forward.

That's why a leading link is preferable to a trailing link. The swing arm pivot is below the axle. So the wheel swings up and back as the suspension compresses. That backwards movement actually increases with suspension travel.

The wheelbarrow demo was meaningless. While it's a reasonable analogy of a trailing link suspension, it's no demonstration of the leading link principle at all. That's because when it's in "leading link" mode (barrow being pushed rather than pulled) the swing arm pivot point (where he's holding the handles) is above the axle, so the arc of suspension travel is going the wrong way. The wheel is trying to move forward into the obstacle as it rises. Of course it wasn't going to work  ::).

I'm happy to draw some diagrams of suspension movement if you aren't convinced.

Actually, the same goes for a motorcycle's rear wheel. Ideally it should move back a little as it hits a bump. That's why the swing arm pivot point is always above the wheel's axle. I think I read somewhere in a book about motorcycle suspension that the swing arm should be at an angle of about 15? to the ground with the rider seated on the bike. The shallower that angle gets, the harsher the rear suspension will be.
 
The wheel barrow digs in being pushed but rolls being dragged is due to weight transfer and the inability of the wheel to accelerate over the bump. The wheel slows as it hits the bump, weight is transferred and the wheel barrow digs in. Leading link forks do the same because the arc of wheel travel points towards the bike, whereas trailing links arc away from the bike.
The rear swing arm on a bike is a trailing arm, it?s easier to push a bike forward over a bump the push it back over a bump for exactly the same reason.
I have ridden a lot of off road sidecars and mucked about with geometry using eccentrics to get different results. I have had sidecars built by Wasp and Robin was very keen on trailing link but they self centre to such a degree it makes it harder to steer, which is why leading link prevails.
 
OK, I see you remain unconvinced. Your arguments seem to be based on intuition and notions that unsupported by engineering principles. I could offer counterpoints to your claims, and was actually about to launch into further diatribe, but then decided not to let this thread get into an argument. Not that I think either of us would get pissed off or start throwing insults, it's just that you seem to be resolute in your belief (as am I) so further argument probably won't get us anywhere.

I think the main focus of this forum is to enjoy our Laverda ownership, riding and maintenance. Not to get into seemingly pointless arguments about technicalities.

Stay safe and enjoy your bikes.

Cheers,
Cam
 
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