Ikon Shock Springs.

Greg Parish said:
Brett, you couldn't be more wrong.
And your sarcasm and denigration of Vince's riding makes your post even more wrong. Please try to be poilte, there has been enough disrepect on the forum this week. You have quoted anti-squat.

Dellortoman is absolutely correct.

Laverdas squat under hard acceleration due to the short swingarm and placement of the drive sprocket in relation to the swingarm pivot. It is the bane of all racers using Laverda framed bikes.
Installing longer shocks alleviates it somewhat but introduces other issues
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Greg, back off Brett..  You have no idea of the relationship between Vince and Brett - they are thick as thieves.


Yogi
 
Yogi 100%, my bike would be parked up if it wasn't for Bretts unbelievable help over the years, BUT everyone can be complicated at times. My biggest problem is I am away in the bush 3 and a half weeks in the month and when I am back in Sydney I have really serious family shit that happening that exsesabated by me being away. I must have the most painful stupid lifestyle about but that's what it is.
 
O and BTW I am not saying I am right or wrong with anything I post here, but it is my considered opinion. All the stuff I do is at my risk and I always try and report what effect it has good or bad so anyone else might learn from what I tried. All my changes are only effective for my weight, not everybody is a slim-hipped 65kgs. There is fuck all info out there on lots of this. And again its a bit of fun for me, nobody is fucking your Mrs or stealing your money or denigrating Massimos memory, so again RELAX.
 
Vince said:
Yogi 100%, my bike would be parked up if it wasn't for Bretts unbelievable help over the years, BUT everyone can be complicated at times. My biggest problem is I am away in the bush 3 and a half weeks in the month and when I am back in Sydney I have really serious family shit that happening that exsesabated by me being away. I must have the most painful stupid lifestyle about but that's what it is.
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Vince, I hear you about Brett - he rode 2 hours plus up to my place to help me out yesterday and then 2 hours plus back.


Having said that, I?ll also say that I feel for you with the situation you are in, and take my hat off to you for what you are doing to help others.


I?ll get you up here one day to spoil you with some good food... always a couple of spare beds here for all Laverda riders and forum members.


Grateful to have you for a friend..


Yogi
 
Thanks mate, I am not a martyr. It's my choice and it suits me. It's my favourite uncle who did heaps for me as a kid. Its what it is, plenty have a way worse out there. Hopefully back to scheduled programming here.
 
Brett said:
Oh how stupid of me what was I possibly thinking it must have been a moment of imagination theories... being that am only a humble mechanic and rider training instructor ..

Must be standing upside down when I watch the bikes racing huh... ,

Oh no damn it looks like Racetech don't understand motorcycle suspension either bugger it....they must be having the same imagination theories...I'm going to apply for a refund under ACL for misleading content... can I use you as an expert witness please.

Shit man so very sorry guys.........by the by I thought all springs were progressive by design guess that is not correct either.

What_would_I_know.jpg
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Blimey mate. Don't get all uppity about it. I wasn't making a personal attack on you, just trying to clear up an apparent misunderstanding.
We all make mistakes but having a dummy-spit about it doesn't make you right. You're just digging yourself into a deeper hole.

The article you quoted is not relevant to our old clunkers. It's about anti-squat rear suspension. But the very existence of such a thing should be triggering questions in your mind. Questions like; why invent anti-squat suspension if bikes don't squat in the first place?

 
Ever seen the rear suspension of any chain drive bike on a dyno?
Adjustable swing-arm pivots are used for what reason?
This can be an interesting thread we can learn from.
 
It's all good, I loves yoos all. Anyway, Icon has agreed to custom make me a couple of straight rate springs at 2.7kg/mm. Bit expensive but that's the best way to be sure they fit. So in 10 days time, I will see how that goes. Tippie I have seen that swingarm hight described as the angle of the swingarm, it has a big effect on the suspension under power application. There was a system developed in the USA years ago that used fixed sprockets above and below the countershaft to take the drive chain action away from the suspension. It was used in the Production on ATK dirtbikes as well as kits to suit other bikes.
 
I pushed the shock bump stop fully down the shaft to see what travel I was using on a typical ride, last Sundays breaky ride. It used 50mm of travel on some pretty bumpy roads, that left 25mm not used. BTW that 50mm included rider sag of 30mm, that's buggar all available travel
That's on the biggest bumps and at its peak movement, who knows how this translates to smaller bumps. Plus I was using the thinly padded solo seat without my usual Air Hawk. Not that comfy, not so stable on bumps leaned over. Hopefully, the new springs arrive from Icon and I can set them up and test it. Be nice to uses 95% of the available piddling 75mm of travel with the ocasional bottoming.
 
Upright, I thought twin shocks didnt have any rising rate so I expect shock travel is the same as wheel travel.
 
Hi Vince.

Wheel travel is never the same as spring travel. It is called the suspension ratio (or by some, the spring ratio). Think of it this way - the shock mounts are nearer to the swinging arm pivot than the wheel axle so will travel less under a certain angle of suspension movement.

Whether the suspension ratio is linear or 'progressive' is another kettle of fish entirely. Totally dependent on the placement of the shock eyes. The ratio will also vary a bit during the stroke of wheel travel.

If you really want to know about your progression, you can sort it out quite quickly without Cam-level math. Just draw it on a piece of paper and measure off at various wheel movements from full extension to full compression. Use the shock length to control the arc of wheel movement.
 
We were taught geometry in high school Vince :D. Set it out on a sheet of plywood. Would be interesting to compare the ratio between wheel and shock movement.
 
There is a huge difference with single shocks, especially when links are used but I don't see it with twin shocks especially when the wheel centre and the bottom shock mount are so close together. I do need to graph this, I don't think there is much difference. Be interesting to see. The whole point of all my threads is to learn something. My favourite thing in Maths as Geometry, pitched plenty of roofs developing the typical 7 different member cuts required.
 
Vince said:
My favourite thing in Maths as Geometry, pitched plenty of roofs developing the typical 7 different member cuts required.
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I think you meant mitre cuts Vince?
Member cuts are different and not sure if you would make it to 7 :o ::)
 
Come on Tom, members as in Common rafters, creepers and hip and valleys and there creepers plus purlins. All have different plumb and level cuts depending on there pitch from level. And I do take the point that an ark scribed from the same point but being far away must have a longer cord length. Anyway, I now have some homework.
 
interesting, I never called them members, always referred to them as just the different mitre cuts, or by their names  as in rafter, hip, purlin etc etc. Been a while since I pitched a roof but.
Still learning.
 
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