Lightest 27.5 DH bike? TREK SESSION 9.9 27.5 19

Dangerholm?

No

I know. You've issued him a challenge tho!

So is that rear shock similar to the Alan Millyard homemade nitrogen pressurized rear shock?

Yeah, it's serial instead of parallel - the movement of the shaft into the damper displaces oil volume and that pushes on an IFP between the air spring and the damper oil, thus providing suspension. Same as Millyard, apparently same as 'tank suspension'

Other shocks are parallel, the relative movement of the eyelets acts on the spring and the damper at the same time.

Aha that is very helpful. So the 'aft' cylinder contains the damper fluid and IFP, and the 'forward' cylinder is the air spring? Very trick.

More or less yeah. Or you could think of it this way. Take a coil shock, remove the spring and do all the springing with the piggyback air pressure behind the ifp.

This is what the Hover is, but of course modified dimensions wise to provide enough spring rate to actually work. A standard coil shock doesn't have enough oil flow to provide a force characteristic high enough and doesn't have the piston surface area high enough to provide high enough forces. And doesn't have a negative spring which the Hover does.

I'm curious how the negative air side of things work in this

@hamncheez2003 good point actually, only now did I think about it properly and I can't seem to put it together in a way that would work...

Okay, I think I wrapped my head around it. Here's a cross section drawing from a Pinkbike article:
https://ep1.pinkbike.org/p6pb17170096/p6pb17170096.jpg

If I annotate it with the spring and air compartments in the manner I think it's laid out, we get this picture:
https://i.imgur.com/Tu1HPBn.png

So it's not the piston rod displacing the oil, it's the piston itself. And it doesn't have a shimstack with the oil flowing through it, like all the other shocks, it just pushes the oil through the bridge where the damping is taken care of.

So it's negative spring and damper on either side of the main piston and damper and positive spring on either side of the IFP.

Congrats Christiaan!!!!

Thanks buddy! You all good and the family?

Yeah buddy!! Hasn't snowed here much yet so I am in heaven!!

one of the most beatiful bikes ive ever seen!

Which DH bike would you rather own? This one or yesterday’s custom gearbox bike of the day?

Custom gearbox high-pivot

Obviously the owner of this bike spared no expense building it, and it seems to be a “dream build” of sorts, but the custom aluminum gearbox bike is more my cup of tea. All else being equal, I’d prefer a 39 pound DH bike with a low and centrally located COG to a 27 pound DH bike. I think if someone gave me this Trek I’d start by installing Cushcore and taping lead weights to the down tube.

Both

Bike of the Day December 10, 2020!