White Bros SC72UL servicing

[scant]

Mine are the later AT/4s and they don't feel that fast, I'd say rather stiff actually, but I haven't serviced them yet as I'm looking for spares.

Do these speed comments apply to the AT4 as well?

The AT4 does feature the high pressure low volume system same as the older UL series. But there's a coil negative spring that can be tuned and I think will help combat topping out. Parts list does not show an elastomer bumper, only a smaller "rebound bumper" in the stack.

the coil spring pushes the fork into its intial travel to reduce the static friction (stiction). the rebound bumper IS the elastomer bumper

 

[IbocProSX]

Thanks, that helps. I'll have a good look at the bumperwhen I open it up.

And as for the neg spring pushing in the initial travel, this also means it's bouncing off it on the top-out, right? And thus a higher rate neg spring rate sinks the fork a little further in the travel when static and helps preventing harsh top out clunks. Important for Clydesdales to get this right as we do run higher pressures.

 

[scant]

Thanks, that helps. I'll have a good look at the bumperwhen I open it up.

And as for the neg spring pushing in the initial travel, this also means it's bouncing off it on the top-out, right? And thus a higher rate neg spring rate sinks the fork a little further in the travel when static and helps preventing harsh top out clunks. Important for Clydesdales to get this right as we do run higher pressures.

the air pressure is pushing against the negative spring, only light pressure against the top out bumper.
honestly? I'd get some fox over the AT4; i've had both & the fox are day & night better.