K9 have just released a topcap for the spring side of downhill forks that is basically a thrust bearing to reduce the springs friction on compression and apparently gives a smoother and more sensitive fork....
now I remember seeing this info regarding rear shocks a few moons ago... and nothing came of it but k9 are adamant that they have done tests and its true it helps...
I found a on a few mtx forums they are deciding if it works or not... some guy said its been tried on f1 and all sorts of sports for years but the consensus is that unless the travels long enough it doesnt do anything...
is 8inches long enough... is it an issue? what do you think? I'm torn between worth a bosh doing it myself but also can see k9 and people making a lot of cash out of a simple thrust bearing?!
Was going to get some sets for the team boys to try out, in theory they will make a difference to what extent is the issue.
Will have a word with some freinds in the F1 and Nascar world to see what they have made of them.
I've got a thrust bearing (with washers) that will fit a DHX coil (FAG AXK 3552); if you want to try them out? I had the same set-up on my SX Trail and I couldn't honestly tell if it was advantageous. The shock was PUSHed and performed brilliantly anyway. A better rider might be able to, but I'm not really skilled/experienced enough to be able to pin-point shock characteristics that could be attributed to the bearing.
I'd happily try it mate, I'm racing next weekend so can certainly give it a good bash
Here are the bits:
[img] 
[/img]
One washer sits on the collar at one end, the the other two sandwich the thrust bearing at the other. In case you don't understand what the numbers in the name stand for, and pardon me if you do, the 35 refers to the internal diameter in mm and the 52 refers to external diameter.
The proper kits have covers to keep crap out of the needles. I greased mine and stripped them to clean every couple of rides. A ring cut from a DH tube can be utilised to make a rough seal.
Shoot me an email and we can sort getting them in the post.
And, hey! What happened with that drum set?
😀 Drum Set is still being illusive! I've been doing work straight since we last spoke! (no rest for the wkd) I did manage to source some evans drum skins for the tops though! I'll get them on one night this weekend hopefully and finally send you some pics... I've got a rough one of them on the floor so I'll send you that but it'd be best seeing it setup
Another question you might already know the answer to...
Why don't they run bearings at both ends or is the pressure fully released with just one end covered?
And if it is good any idea where to get a sealed version?
A few companies have done this for motorbike shocks and yep, people say they feel a benefit but it's not one anyone's been able to recreate on a chassis dyno. Colour me skeptical
is this like a "ti springs feel more sensitive" and its a 50/50 split?
Again, theory is yes, a ti spring would give a lower unsprung mass and therefore more sensitivity as well as the material characteristics being better.
Somebody must have test data for both showing some performance benefit.
Am see my F1 designer mate this week end so will see if he can point me in the direction of some useful data for STW to pick to pieces 😉
Just out of interest, does anyone have any figures for the angle of rotation between the two ends of a coil spring when it is compressed ?
Not used in Nascar or F1 due to small amounts of travel, no data tests for this, question has been asked to freind of a freind working for large suspension company in the Us to see if he has any data tests on these.
Won't it just lower the spring rate a bit?
Not really it will still take X lbs to compress the spring 1 inch.
LoCo - MemberNot really it will still take X lbs to compress the spring 1 inch.
Okay- not the actual spring rate, but the effective one. Since the spring is no longer being resisted against twisting.
Point taken, yes would reduce frictional losses a bit