Jotagas Rear Suspension ?

[b40rt]

Rear suspension must be compromised for hoping against traction ?

[nigel dabster]

I got a reigar shock made for my sherco in 2007 it was a transformation as the standard shoch was absolutely crap with the spring tension the only adjustment.

set up and a good shoch are underestimated even for us club riders.

[biffsgasgas]

So when in Germany a few weeks ago I noticed something that is not common here in the states. There were numerous bikes that had custom shocks with external resivoirs mounted right above the flywheel cover. Most were on teens bikes with obvious support.

So ignorant question. How many custom shock shops are available there in the EU specific to trials?

Here in Detroit we have several MX shock people and auto shock specialty shops but thats pretty rare in comparison to other areas.

--Biff

PS great topic

Edited March 28, 2014 by biffsgasgas

[atomant]

Watching the slow mo vid I can see that trials bikes would very much benefit from "Active" suspension. Now that would be a cool innovation

[nigel dabster]

i spoke to the ohlins shock guy and he said for anyshock to work on continuous usage it needs a reservoir, thats what he has on all the works bikes, pretty sure fuji had it on his bike when they tore it down at shefield one year.

[heavydabber]

As per Newton's 3rd law, every action has an equal and opposite reaction and with Jotagas' design the reaction is straight though the main beam of the frame whereas other makes are vertical and need an outrigger that needs to be quite substantial to react the forces without flexing.

Yup, I'd go with this, the stresses are directed straight up the main frame side-member which is obviously already there, so why not use it for a shock mount?. From an engineering point of view, advantages over a centrally mounted shock are:

No need for the weight and complexity of a braced central cross-member to mount the top of the shock to

Much improved access to shock and linkage maintenance

Allows for a bigger airbox and more direct airflow into carb

From a selling point of view it's novel and different

Disadvantages

Vulnerability to damage

Doesn't contribute to centralisation of mass/weight

I don't personally think that the design of the actual linkage is a million miles different from the old Yam TY/TYZ arrangement, the short link just runs direct to the bottom shock mount, obviously dimensions will have been worked on and optimised since those days and shock technology and development has moved on light years which is where the massive improvements will be, but principally it works in much the same way. But it's thinking "outside the box" and has moved things on!

[telecat]

We have just fitted an Ohlins to the Jotagas. First time out it appears that it handles the energy better than the Olle. The Shock and spring are a little larger than the Olle so you need to move a few spacers around to push the exhaust away.