Vorsprung Suspension Corset Fox Air Shock Upgrade

[jrewing]

Because they won't fit on some frames, and some manufacturers won't warranty their frames if used with a coil shock. Should really cut that harsh initial feel of fox air shocks if the graph is accurate:

Wow.. What shock model has that much breakaway resistance. Surely that's not reflective of a quality high end air shock?
Is that S's company vorsprung

 

[indica]

. Should really cut that harsh initial feel of fox air shocks if the graph is accurate:

I don't experience that at all. The Float X on the new Sanction is very supple.

 

[moorey]

Also available from TEKIN
I too will be getting one of these shortly.

Still trying to polish that turd?

 

[MARKL]

Because they won't fit on some frames, and some manufacturers won't warranty their frames if used with a coil shock. Should really cut that harsh initial feel of fox air shocks if the graph is accurate:

I look forward to the real world results but...

I may be missing something (or I am just too old and cynical) but if I look at that graph, the vertical lines I assume reflect compression of the shock, each vertical line is 20%.

So the big benefit of the Corset is mostly in the first 5% of travel and its pretty much all over by 10-15%, beyond that it runs parallel with the standard Fox shock...otherwise known as slightly different air pressure

So better break away when you first sit on the bike and all over by the time bike settles into its sag at 25ish%...:whoo: not one of my criteria but hey :noidea:

 

[willsy01]

Would appreciate some feedback from those that have ordered them.........i'm officially intrigued.

 

[Rhys_]

This looks like a great product and I'll hopefully get the chance to test one soon.

A few points:

This will benefit all bikes running Fox air rear suspension, as no matter the characteristics of the rear linkage, the high initial resistance to movement (or high spring rate) at the start of an air shock's stroke is still a factor. Yes, some bikes are worse than others in dealing with this high initial spring rate, and it is these the Corset will probably benefit the most. E.g. the vpp bikes (outside of the V10) have a falling rate at the start of the travel (leverage ratio from low to high) which basically accentuates the negative characteristics of an air spring.

MARKL, don't be fooled into thinking your bike spends little time from the start of stroke to your sag point. There will also be better mid stroke support

 

[ajay]

I look forward to the real world results but...

I may be missing something (or I am just too old and cynical) but if I look at that graph, the vertical lines I assume reflect compression of the shock, each vertical line is 20%.

So the big benefit of the Corset is mostly in the first 5% of travel and its pretty much all over by 10-15%, beyond that it runs parallel with the standard Fox shock...otherwise known as slightly different air pressure

So better break away when you first sit on the bike and all over by the time bike settles into its sag at 25ish%...:whoo: not one of my criteria but hey :noidea:

Perhaps when you're sitting on it in the car park. Your shock does in fact decompress when you ride, hence small bump compliance being a well sort after trait.

 

[placebo]

The current bike I'm using a float-x on is a pivot mach 6, and replacing a firebird with a cane creek coil, the float-x feels like a choppy, harsh, yet paradoxically later in the stroke undersprung, underdamped shock. It's poor compared to the two coil sprung bikes I owned to compare it with, and the corset should help remedy the air spring contribution to this trait. The debonair models released by rockshox, and the fox prototypes seen around are definitely similar ways to skin the same cat. Also, the trail setting on the float-x doesn't seem to provide enough damping through the stroke despite increasing it initially. I'm using a cane creek air at the moment on that bike and it's a definite improvement. I'd try the ccdb coil for a bit to compare, but the shock won't fit the frame without increasing the diameter of the rear eyelet, and that would prevent it being used on the bike it was originally for.

 

[MARKL]

Like I said I look forward to the real world results. I would like to see the difference between a freashly serviced Fox shock and the Corset, I am intruiged.

This looks like a great product and I'll hopefully get the chance to test one soon.

A few points:

This will benefit all bikes running Fox air rear suspension, as no matter the characteristics of the rear linkage, the high initial resistance to movement (or high spring rate) at the start of an air shock's stroke is still a factor. Yes, some bikes are worse than others in dealing with this high initial spring rate, and it is these the Corset will probably benefit the most. E.g. the vpp bikes (outside of the V10) have a falling rate at the start of the travel (leverage ratio from low to high) which basically accentuates the negative characteristics of an air spring.

You are right that more pedaling orientated VPP bikes have a falling rate at the start of travel, it is more pronounced on a Blur than say a Nomad - I have always assumed that was to improve pedaling performance. Either side of the sag point the spring rate increases so the sag point is the natural point the suspension wants to return - therefore the spring rate resists pedaling forces.

MARKL, don't be fooled into thinking your bike spends little time from the start of stroke to your sag point. There will also be better mid stroke support

The mid stroke support in that graph is absolutely parallel - you would get the same thing by increasing the spring rate.

Perhaps when you're sitting on it in the car park. Your shock does in fact decompress when you ride, hence small bump compliance being a well sort after trait.

I agree that small bump compliance is an important trait but it is a trait that is either side of the sag point, not from 0 travel. Say, small bump compliance is 5-10% of travel either side of the sag point - so if we take a typical bike with 25% sag, small bump compliance happens between say 15% and 35% of travel, not between 0 and 10% of travel. And between 15-35% the performance is essentially the same

 

[Rhys_]

Like I said I look forward to the real world results. I would like to see the difference between a freashly serviced Fox shock and the Corset, I am intruiged.



You are right that more pedaling orientated VPP bikes have a falling rate at the start of travel, it is more pronounced on a Blur than say a Nomad - I have always assumed that was to improve pedaling performance. Either side of the sag point the spring rate increases so the sag point is the natural point the suspension wants to return - therefore the spring rate resists pedaling forces..

A falling rate at the start of the travel is actually one of the least desirable ways to increase an air shock equipped bike's pedalling efficiency. This is because the lower leverage ratio at the start of the travel compounds the high initial spring rate of an air shock, making this even more noticeable. A Pivot Mach 5.7C, for example, starts out with a high leverage which decreases. This helps overcome the high initial springrate of an airshock. Working with anti squat etc are other ways to increase pedalling efficiency without resorting to a falling rate.

The other negative affect with the VPP is the higher leverage ratio as you get to the mid stroke - this again exacerbates the natural characteristics of an airshock, in this case the lack of mid stroke support.

Anyhow, not here to destroy people's VPP dreams.

The mid stroke support in that graph is absolutely parallel - you would get the same thing by increasing the spring rate

Sure, at the expense of just about everything else. This is obviously the advantage of the Corset - you don't need to adversely affect your sag point, small bump sensitivity and bottom out to get that extra mid stroke support.

 

[placebo]

A falling rate at the start of the travel is actually one of the least desirable ways to increase an air shock equipped bike's pedalling efficiency. This is because the lower leverage ratio at the start of the travel compounds the high initial spring rate of an air shock, making this even more noticeable. A Pivot Mach 5.7C, for example, starts out with a high leverage which decreases. This helps overcome the high initial springrate of an airshock. Working with anti squat etc are other ways to increase pedalling efficiency without resorting to a falling rate.

Pivot 5.7C rate:

The other negative affect with the VPP is the higher leverage ratio as you get to the mid stroke - this again exacerbates the natural characteristics of an airshock, in this case the lack of mid stroke support... This is obviously the advantage of the Corset - you don't need to adversely affect your sag point, small bump sensitivity and bottom out to get that extra mid stroke support.

Nomad rate, it's pretty much the inverse of the 5.7C:

I've had a couple of VPP bikes, and still have a slopestyle, you really need to get your sag right to get the best out of these bikes.

 

[Rhys_]

Exactly. My comments are based upon graphs such as these

 

[willsy01]

Pivot 5.7C rate:

Nomad rate, it's pretty much the inverse of the 5.7C:

I've had a couple of VPP bikes, and still have a slopestyle, you really need to get your sag right to get the best out of these bikes.

Got the 2012 Commencal Meta AM graph there per chance?

 

[Ivan]

Got the 2012 Commencal Meta AM graph there per chance?

They look like Antonio's charts. Google linkage blogspot.

See these charts ( I know there under the SX but the AM is in the charts as well) http://linkagedesign.blogspot.com.au/2012/02/commencal-meta-sx-2012.html?m=1

 

[willsy01]

Superb, thanks.

 

[blacksp20]

A falling rate at the start of the travel is actually one of the least desirable ways to increase an air shock equipped bike's pedalling efficiency. This is because the lower leverage ratio at the start of the travel compounds the high initial spring rate of an air shock, making this even more noticeable. A Pivot Mach 5.7C, for example, starts out with a high leverage which decreases. This helps overcome the high initial springrate of an airshock. Working with anti squat etc are other ways to increase pedalling efficiency without resorting to a falling rate.

The other negative affect with the VPP is the higher leverage ratio as you get to the mid stroke - this again exacerbates the natural characteristics of an airshock, in this case the lack of mid stroke support.

Sorry if I sound like a numpty, but it's hard to get my head around leverage ratio graphs and apply them to my bike. Would you expect the corset to work well with a VVP style leverage ratio?

I only ask as I have a 2011 575 (essentially the same a 2013) which apparently has a very simillar leverage curve (found on http://linkagedesign.blogspot.com.au) to the VVP curve listed earlier. I am a little hesitant to give one a go as I'm unsure if it will work well with the 575 design but also my weight (120kg) requires 250psi in the shock already and I've been told I might have to increase that to 300psi or more if I fit a corset. Steve at Vorsprung didn't comment on my frame design and if it would work well or not with it.

Would the corset's increased spring rate in the midstroke help with the higher leverage ratio of the 575 to remove the blow through?

 

[MARKL]

Sure, at the expense of just about everything else. This is obviously the advantage of the Corset - you don't need to adversely affect your sag point, small bump sensitivity and bottom out to get that extra mid stroke support.

Missed my point, they are not using the same sag point, assume the sag point is 25% then the shock displacement should be the same for either shock at that point. Once you adjust for that the curves beyond the sag point are pretty much exactly the same. The way it is presented is not an apples and apples comparison.

Thinking about it more the thing that interests me is the graph, Vorsprung say "However, a particular standard Fox air spring curve has a spring rate that drops by more than 90% from the beginning of the stroke..."

So is it just one model or all models that exhibits this behavior? One example or all examples? Or one cycle or thousands of cycles on a shock dyno? If it is just one cycle that is a very different thing compared to use where the shock is constantly moving. Is it a stiction thing? Does it occur if you start the stroke from the sag point instead of zero? I am too cynical to believe one graph without questioning...

A falling rate at the start of the travel is actually one of the least desirable ways to increase an air shock equipped bike's pedalling efficiency. This is because the lower leverage ratio at the start of the travel compounds the high initial spring rate of an air shock, making this even more noticeable. A Pivot Mach 5.7C, for example, starts out with a high leverage which decreases. This helps overcome the high initial springrate of an airshock. Working with anti squat etc are other ways to increase pedalling efficiency without resorting to a falling rate.

The other negative affect with the VPP is the higher leverage ratio as you get to the mid stroke - this again exacerbates the natural characteristics of an airshock, in this case the lack of mid stroke support.

Anyhow, not here to destroy people's VPP dreams.

I'm not arguing suspension systems (I have both DW and VPP bikes), I agree that a falling rate at the start of travel is counter intuitive but I also find the falling rate of an Ironhorse Sunday over the last 40% of its travel counter intuitive :noidea: but hey they are a great bike and ride well and at the end of the day that is what counts.

I don't get the 'high initial spring rate of an air shock' I reckon that is BS. Air shocks increase in pressure as they compress as a result of the volume reducing and as a result the spring rate increases, the Vorsprung graph makes no sense to me with the really high spring rate at the begining (hence my previous question - if it a single cycle then stiction would play a big part in the readings). The graph below shows DB air with different air cans and the effect they have on spring rate, I know there are no numbers but it makes more sense.

 

[Rhys_]

Sorry if I sound like a numpty, but it's hard to get my head around leverage ratio graphs and apply them to my bike. Would you expect the corset to work well with a VVP style leverage ratio?

I only ask as I have a 2011 575 (essentially the same a 2013) which apparently has a very simillar leverage curve (found on http://linkagedesign.blogspot.com.au) to the VVP curve listed earlier. I am a little hesitant to give one a go as I'm unsure if it will work well with the 575 design but also my weight (120kg) requires 250psi in the shock already and I've been told I might have to increase that to 300psi or more if I fit a corset. Steve at Vorsprung didn't comment on my frame design and if it would work well or not with it.

Would the corset's increased spring rate in the midstroke help with the higher leverage ratio of the 575 to remove the blow through?

I can't comment on your shock pressure issue, sorry. I'm sure if you emailed Steve he would give you some guidance.

Just based purely on that linkage diagram, I think your bike would benefit from the lower initial spring rate and increased mid stroke support. Looking at the graph, you can see the leverage ratio begins at a lower number and rises to a higher number (in the mid stroke). This is a digressive curve = falling (shock) rate. In really simple terms (as I understand it), a higher leverage ratio number means there is more leverage on the shock, hence making it easier to compress. A lower number=less leverage=harder to compress. When a curve such as yours (lower leverage initially, to higher mid stroke) is combined with a traditional air shock which naturally has high resistance to movement initially, and a lack of mid stroke support, you can see where the problems arise. On bikes such as the Pivot, a high leverage initially helps counteract the air shock's high spring rate, and the lower leverage mid stroke puts less leverage on the shock, helping it to not blow through the travel.

 

[Ivan]

MarkL
The charts your comparing are different, because the y axis is different. The CCDB chart is Force (lbs) and the Vorsprung chart is spring rate (lbs/in).

I believe Vorsprung has a force vs displacement chart on their blog.

 

[Ivan]

Here it is