Do they work on air shocks?

Do they work on air shocks?

I hope that’s a joke.

They are not quite as effective on air, only an eleventytwo percent increase in speed has been noted.

However if you combine them with the needle bearings to replace your bushes and liberally coat the lot with snake oil, you can expect similar levels of performance as a coil.

So…I need snake oil and I’ll get an eleventytwo percent increase in speed?

Can you buy it in Evans?

Do they work on air shocks?

they’ll definitely be just as effective on an air shock…

I love the way the two graphs are quoted as proof that this thing works and that everyone agrees. Can anyone of those people who agree explain to me what is going on with the graph!

You only need one, the misconception that you need 2 stems from trying to turn the spring while pre-loaded which turns against the two ends. In reality only one end needs bearing-ing and if you wanted you could bond the shock to the other end and see the same results.

It will make a difference, whether it’s perceptible – not sure, never tried and I’ll save my answer for if I ever do, but considering the rear shock technology that makes slightly varying damping ratios across the stroke and the shear volume of cash thrown at such shocks due to their superiority of performance, it’s reasonable to assume that either everyone with a specially valved shock is talking nonsense or that these may indeed be useful to some degree.

I love the way the two graphs are quoted as proof that this thing works and that everyone agrees. Can anyone of those people who agree explain to me what is going on with the graph!

What concerns me is that the top graph is not centred about 0 so seems to have all resultant forces in the negative (impossible on a shock dyno IIRC but could, I suppose be poor calibration and zeroing of the hardware?). I’m also a bit confused because the left axis is shock speed and would normally be displacement. This graph shows no change of piston velocity with increasing frequency?

Actually, I was wrong in thinking there – all negatives are possible with preload but suggest some strange action and not the same test rig as the one which is cyclic around zero. Hmmm. I’d like to see his test rig.

What concerns me is that the top graph is not centred about 0 so seems to have all resultant forces in the negative (impossible on a shock dyno IIRC but could, I suppose be poor calibration and zeroing of the hardware?). I’m also a bit confused because the left axis is shock speed and would normally be displacement. This graph shows no change of piston velocity with increasing frequency?

Hi all, The testing was done on a machine which duals as both a dyno and a straight forward compression/tension tester, which is designed to work within a range of +/- 25T. As a result of this, the amount of force needed to cycle the damper was quite small in comparison. Now unfortunetly, we had to ‘make do’ with this machine, but as it was over 10yrs old it occasionally have a hissy fit when dealing with ‘relatively’ small forces where it would retract completely (ripping a shock apart) or not return to the dead-top point we set. To try to avoid this happening, we compressed the damper to a 30% sag level and operated +/-10mm from this to avoid damaging the damper if it went pairshaped, hope that answers why the force started in the negative…

Oh speaking of, the force being read is not the force acting on the damper, its the force that the damper is resisting the motion of the work head with. Also when the damper was set at the datum point the force & displacement had to be zero’d (explaining why some of the graphs start at zero).

[/quote]Your plots are force vs speed which is an interesting plot for shocks but makes it a tad hard to see what’s going on

The reason the plots were made as so, were initially, because the data that the machine spits out was in the force/time/distance format, but it was mainly because the data was being used to calculate the change in damping ratio through the stroke, giving us an indication as to what shim stacks gave what results etc…

Admittedly the work needs to be taken further with more validation done but as I only had a short time and limited/’make-do’ equipment to take the project with, I did the best I could. This isn’t a cop-out but I’m just trying to explain why certain testing equipment was used instead of equipment more suited for the task.

With regards to two/one bearings discussion I have seen in quite a few places, I only had time in the project to test two bearings, as this was more of a side-thought than the direct aim of the work I was trying to carry out. Because of this, I have only recommended two bearings as I know the results for that, and didn’t want to lead people down the one bearing path with just the one when I wasn’t completely sure with test data to back it up.

Hope this helps 🙂

Ed

Hi Ed, interesting study area, I know how it feels to be dealing with old Uni equipment that’s been abused for years 😉

If you need any kit/parts for further tests feel free to drop me a mail

I’ve fitted a set of these to the shock on my Iron horse Sunday DHX5.0.

The thrust bearing spacer/washer (cage thrust assembly) that sits closer to the rebound adjust is not fixed and moves about 5mm across, this could connect with the shocks body while riding.

Anyone thinking of using these thrust bearings should look out for this, the actual thrust bearing and upper spacer are fine, however the lower spacer is unstable.

Does anyone know of any way to bond the spacer to the top of the spring to stop it from moving, I’m going to use some super glue for now 😯 , so that I can test the thrust bearings and see what I think, however I’m not sure if this will hold.

I’ve also filled the thrust bearings with grease to prevent them from rusting.

metal epoxy any use?

By the way these bearings are now available as drop in units for coil forks (none uturn of course)

These bearings and similar components have been available for ages, the problem isn’t that they don’t exist, the real problem is that they are too expensive for most riders to afford.

A lot of riders can’t even afford to have thier bikes serviced, never mind buy upgrades for coil shocks.

I don’t think I will find a way to ensure the the top spacer will not misalign and connect with the shock main body, that said I’ve been working all day so haven’t had a chance to play about with it today.

What a load of bollocks

kaesae they do exist and are £16

cruzheckler

any chance of a link?

think there’s an artivcle on southern downhill. Also i think this has been discussed on stw a while ago.

http://www.k9industries.com/?page_id=103&parent_product_section_id_1=4

For forks a three-peice roller bearing thrust washer can be had for about £3.50 from your favourite supplier. 😉

sounds nearly as good as one of these Denon AKDL1. You might have caught an earlier thread on the subject.