EErockMiata

knowledge dump much appreciated.

turbofan

iTrader: (1)

Definitely appreciate all that info, thanks for laying it out.
<br />
<br />Can't wait to try mine on the track.

hector

Somebody call a moderator. Shaik has taken over Emilio's account!

Just kidding. Xida is a good shock. MCS is a good shock. Can't we all just get along?

arbinshire

Unlike Shaik, there isn't any meandering thought process or stupid metaphors only he understands. Emilio's information is to the point.

dcamp2

iTrader: (4)

Re: Hysteresis due to N2 charge:

At least on mountain bikes it's really hard (impossible) to differentiate between hysteresis and changes in spring rate. Basically the N2 charge is acting like a small air-spring, which gets added to your regular spring while in use. And since Miatas are running 400 lbs/in springs and up- you probably won't notice the N2 charge adding 20-30 lbs of spring rate.

On bikes our gas-charge starts at 500 psi for certain shocks and can go upwards of 3000 psi at bottom-out (due to extreme packaging restrictions). In the end- it doesn't affect the ride quality. The normal spring is providing so much greater force that you end up not noticing the gas ramp.



TL;DR Don't worry about Hysteresis.

sixshooter

iTrader: (12)

Thank you for the detailed explanation, Emilio. When or if I get serious about my track days I feel confident the Xidas are the best choice available due to the time and effort spent to develop them. I appreciate your efforts to develop products for the platform.

aidandj

iTrader: (5)

Nobody has answered my question about why hysteresis is bad...

Leafy

iTrader: (1)

You know how when you hit a bump with cheaper shocks, that are valved correctly, like revalved koni yellows, and you know you didnt hit the bump stop, but its still a jarring impact? Thats why hysteresis is bad.

curly

iTrader: (25)

I always thought about it as two bumps, like curbing. If you hit the first curb, do you want the 2nd curb to feel the same, or different? But I know zilch about shocks.

aidandj

iTrader: (5)

That's not it. Its the difference between accelerating and decelerating. Not 2 whole separate cycles. I think (same not knowing anything about shocks applies to me)

dcamp2

iTrader: (4)

Read this: http://www.penskeshocks.com/assets/T...ing%202-04.pdf

From the article: What is Hysteresis?
Hysteresis is lag in response of a damper usually due to compressibility of damper fluid from high pressures in the damper.


I know penske is obsessed with hysteresis reduction and pressure balancing and the like, but most of our performance gains (rock shox) come from reducing friction throughout the system, and keeping dirt out and oil/air in.

That said Penske is making shocks that cost $50000 a corner and we make shocks that cost $150. BIG difference.

Junkwhale

Would a longer rear shock with extended tophats avoid this compromise?

emilio700

iTrader: (3)

NB mounts are already about as extended as you can get. Extending further and retaining the coaxial perch would involve punching a big hole in tub to clear the spring OD. Easier to invert the damper but then you run into halfshaft clearance issues.

Trust me, if there were a simple solution to the packaging issues on the NA/NB rear, we would have found it about two decades ago.

In any case, there isn't as much of a compromise as you might think. Xidas work exceptionally well. IOW, don't overthink it.

gtred

I think the reason that some shock tuners may try to limit hysteresis is that: it is easier to tune a shock by turning an adjuster... say one click, and then know to expect... say a 25# change across the entire working range of the shock, than it would be to try to work with a non-linear adjustment (high hysteresis shock).

Efini~FC3S

iTrader: (4)

Emilio seems to like touting how many national championships the XIDAs have won (the quoted post just one of multiple).

Someone should look up how many professional road racing championships XIDAs have won vs. MCS.

I'm guessing one is >0; and the other is 0...

emilio700

iTrader: (3)

Since the question is NA/NB Miata coilovers, not coilovers in general, your question is irrelevant. How many Paris-Dakar has MCS won, Tractive has won several. Who cares?

What the folks reading this thread care about is, you know their car.

Weak troll is weak.

wannafbody

iTrader: (1)

As I pointed out earlier, the twin tube shocks on the ND are superior to Penske shocks on the NC, therefore $25 twin tube shocks are the superior shocks. All kidding aside, the shocks can't fix a poorly designed suspension. There really isn't any "best" shock. It all depends on which metric you are measuring.

Junkwhale

Bit of a thread resurrection: does anyone know whether the MCS shock dyno plots in this thread are for a front or rear shock?

I'm trying to come up with a 'off the shelf' bilstein shim stack (or a couple for diff spring rates) everyone in the budget/ebay bilstein threads can use - there's heaps of places that will revalve a bilstein cheaply, the difficulty comes in knowing what to specify.

From what I can tell both XIDAs and MCS are both using similar valving - both digressive (assuming something sensible happens off the scale shown on the MCS graph which only goes to 5IPS), both similar forces:


(I've overlaid the MCS full soft/full stiff from this thread on the front xida plot, but the MCS graph may actually be for a rear...)

aidandj

iTrader: (5)

MCS are linear. Gen2 xidas are digressive.

Junkwhale

Fair enough - I was thinking they may digress after what's shown on the graph (5IPS) at least for rebound - it doesn't really matter though. Either way, the forces are pretty similar under 5 IPS (in the bleed range shown), so I'm interested in whether the graph posted for the MCS was a front or rear.