[papajohn]

All the recent hub-bub about "stable platform" shocks, and I am willing to come right out and admit it to you people, I am clueless as to what part of the shock is the platform.

I just found this comment by someone posting about Romic's Coil Rear Shock, "The bob knob definitely works again but it seems to affect the entire compression stroke, not just the platform."

I have four Romic Twin Tube Coilover rear shocks, and as hard as I look at them, I don't see no "platform". I've got a few Manitou forks, both Sherman and Minute that have the SPV feature, and I have literally totally disassembled them and rebuilt them, and I didn't find no "platform" inside them.

What are we talking about here, and how come everybody else seems to know what it is?

John W.

 

[Strafer]

"stable platform" is not a piece of hardware; it is term for new technology that keeps suspension "stable" to pedal inputs.

 

[Jm.]

All the recent hub-bub about "stable platform" shocks, and I am willing to come right out and admit it to you people, I am clueless as to what part of the shock is the platform.

I just found this comment by someone posting about Romic's Coil Rear Shock, "The bob knob definitely works again but it seems to affect the entire compression stroke, not just the platform."

I have four Romic Twin Tube Coilover rear shocks, and as hard as I look at them, I don't see no "platform". I've got a few Manitou forks, both Sherman and Minute that have the SPV feature, and I have literally totally disassembled them and rebuilt them, and I didn't find no "platform" inside them.

What are we talking about here, and how come everybody else seems to know what it is?

John W.

The romic most definitely has a pedaling-platform. A pedaling platform is simply an increase in low-speed compression damping with a blow-off.

A pedaling platform is low-speed compression damping that has some sort of "blow off" feature that allows the suspension to activate. For romic (and push) shocks, this damping is "softer" and not quite as adjustable, either for more damping or less in my opinion, but it is most definitely there. The difference between pedaling a fox and a romic is dramatic, and this is due to low-speed compression damping. On your romic, it is called the "bob knob" by some because it increases that low speed compression and will decrease the bobbing if you "turn it up" (without affecting the high speed operation much).

On the 5th element shocks, there is a pneumatic valve that varies the amount of low speed compression depending on the air pressure. This also has a "blow off" function. It works in a different way than simple low-speed compression shims, but the end result is the same, hence we use "pedaling platform" to describe different shocks with different mechanisms, that have a similer end result.

Of course, when talking about the romic, it's hard to know what is exactly going on, some people report that their shock "looses" it's platform over time, it just fades away. This happened the first time my romic "blew", there was no oil or anything, but the compression knob made absolutely no difference one way or the other. The guy talking about the romic seems to be talking about some sort of malfuction John, when the compression-adjustment affects the entire range it is working more like a fox-compression feature, which means you can't increase it without severely degrading the high speed performance (because it affects the entire range with NO blow-off). So when talking about malfuctions, either NO compression damping or something creating damping across the entire range, it may get even more confusiong. Underdstanding the first three paragraphs will help hopefully

BTW, I've found new, and even crazier trails in flagstaff

 

[Dougal]

The platform is just a damping threshold.
The damper acts very sluggish on compression unti it gets a hit sufficient to open the valves.

On many platform dampers (like the romic) you can adjust them to run open (no platform).

 

[Jm.]

On many platform dampers (like the romic) you can adjust them to run open (no platform).

I have to disagree with this, there is still a good amount of low speed compression damping on the romic, even when it's ran full "open". On really soft "hits" or at low speed, it seemed real prevealent and the feel was that it was trying to buck me a little, rather than go into it's travel. Even with "zero" on the compression adjuster, it still has a lot more low-speed compression than say a fox vanilla. The thing is that it's not a "harsh" platform, it's fairly "smooth"...

 

[papajohn]

"stable platform" is not a piece of hardware; it is term for new technology that keeps suspension "stable" to pedal inputs.

I was being facetious about looking for the "platform", but I really did not know what was meant by the concept, and thanks to the posts here I think I grasp what is being talked about here.

I have an 03 Sherman Firefly that is not an SPV fork, and an 04 Sherman Firefly with an SPV. When I stand up to pedal hard there is a world of difference betweem these two forks in what happens to the front end of the bike, and I assume that this is a demonstration of the "stable platform" while pedaling.

John W.

 

[SinglePivot]

firefly 03 vs 04

How would you compare the two forks in suspension feel?

thanks,

-Sp

I have an 03 Sherman Firefly that is not an SPV fork, and an 04 Sherman Firefly with an SPV. When I stand up to pedal hard there is a world of difference betweem these two forks in what happens to the front end of the bike, and I assume that this is a demonstration of the "stable platform" while pedaling.

John W.

 

[derby]

Yes, a Romic always has platform effect

I have to disagree with this, there is still a good amount of low speed compression damping on the romic, even when it's ran full "open". On really soft "hits" or at low speed, it seemed real prevealent and the feel was that it was trying to buck me a little, rather than go into it's travel. Even with "zero" on the compression adjuster, it still has a lot more low-speed compression than say a fox vanilla. The thing is that it's not a "harsh" platform, it's fairly "smooth"...

Darren ( of Push Industries) told me when he worked with Romic, that with the Romic "bob knob" spring completely unloaded there is a higher rate of initial shaft movement compression damping and more compression through out travel than a non-platform shock such as a (pre-Propedal) Vanilla, which also has compression damping, but none at initial movement and much less throughout compression travel.

The term "platform" refers to either firm slow speed shock compression damping or a suspension path designed with resistance to free suspension compression, for a less squishy feel when normally pedaling, while bump activation of the suspension is more freely compliant.

- ray

 

[Jm.]

or a suspension path designed with resistance to free suspension compression, for a less squishy feel when normally pedaling, while bump activation of the suspension is more freely compliant.

- ray

Woah, i've never heard of the "path" theory. Chain tension has always been...well, chain tension, it's not a platform, it's simply chain tension that is fighting bob, through an axle path that gives the desired amount...

Sounds like a Santa Cruz definition or something

 

[Dougal]

Woah, i've never heard of the "path" theory. Chain tension has always been...well, chain tension, it's not a platform, it's simply chain tension that is fighting bob, through an axle path that gives the desired amount...

Sounds like a Santa Cruz definition or something

There are three main components of bob.

1. The bikes reaction to acceleration.
2. The bikes reaction to chain tension.
3. The clown jumping up and down on the seat.

The rear suspension axle path defines the reaction to the first two. The shock valving determines the third.

 

[papajohn]

How would you compare the two forks in suspension feel?

thanks,

-Sp

With the exception of the marked decrease in movement from pedaling with the 04 SPV, the two forks are pretty much indistinguishable in how they handle the terrain (both are wonderful, it is a great fork, and easy to disassemble and work on in your garage).

The 04 has a travel adjustment that is a full 40mm drop, while the 03 only has a 20mm change in the travel adjustment, and that alone makes the 04 way superior for my taste.

John W.

 

[Steve from JH]

I have to disagree with this, there is still a good amount of low speed compression damping on the romic, even when it's ran full "open". On really soft "hits" or at low speed, it seemed real prevealent and the feel was that it was trying to buck me a little, rather than go into it's travel. Even with "zero" on the compression adjuster, it still has a lot more low-speed compression than say a fox vanilla. The thing is that it's not a "harsh" platform, it's fairly "smooth"...

I think Dougal is right. When the Romic bob knob is all the way open there is no preload on the spring behind the ball valve that controls the oil bleed from inner to outer chamber. That means that any amount of force on the shaft will open the valve slightly (ignoring stiction). So there's no threshold and no "blow-off".

To me that would mean no platform. There still might well be more slow speed compression damping than on, say, a Vanilla. But that's a different statement.

 

[Jm.]

To me that would mean no platform. There still might well be more slow speed compression damping than on, say, a Vanilla. But that's a different statement.

More low-speed compresion would mean a platform..., maybe not working in the same way the "bob-knob" does, but it's not going to change the outcome (pedaling platform, better pedaling, etc)...

 

[Dougal]

More low-speed compresion would mean a platform..., maybe not working in the same way the "bob-knob" does, but it's not going to change the outcome (pedaling platform, better pedaling, etc)...

A platform needs force to overcome and start movement. Where a shock with no platform but lots of low speed compression, any amount of force will start movement, the movement will just be very slow.

Low speed compression damping and platforms aren't the same thing.

 

[Poser]

Derby, Dougal, or Steve from Dh- unrelated question...

I was about to purchase a fifth element coil shock to replace a fifth element air. I was set to purchase the coil until I read a thread about what shock for a falling rate suspension. The concensus from the thread was that air made the bike feel more stable.

I have a Medium Tomac Six shooter -

http://www.tomac.com/2003/bikes/six_shooter.html

I believe it is a falling rate single pivot. I use the bike for light freeride. Before I put a Fifth Element air shock on it, I called the Six Shooter "the rambling wreck". With the Fifth Element air shock I like the bike. Do you think by going to the fifth element coil on a falling rate single pivot, I will injury the performance in comparison the Fifth Element Air?

thanks

 

[Jm.]

Do you think by going to the fifth element coil on a falling rate single pivot, I will injury the performance in comparison the Fifth Element Air?

thanks

Of course not, that's why the 5th element COIL shock was developed. Bikes like the bullit and heckler are extreme falling-rate designs, and they use 5th element coils no problem. The key is to adjust the progression by screwing in the air-chamber size adjustment. Smaller chamber = more progressiveness. Larger chamber = more linear of course.

Now if you went to a fox vanilla, romic, or push-modified fox, you wouldn't get the same kind of progressiveness and you would not get adjustable progressivness like the 5th elment coil shock has. To put it simply, the 5th element has adjustable progressiveness, which makes it a perfect shock to mate up with a single pivot bike. Single pivots are either regressive, digressive, or they approach being "linear"(but they never are truely linear). In any of these cases, a progressive 5th element shock that has adjustable progressivness is an excellent pairing.

 

[Poser]

Thanks for the help and

is my bike "regressive, digressive, or they approach being "linear" " and is it a high or low or mid pivot

http://www.tomac.com/2003/bikes/six_shooter.html

Thanks again

Of course not, that's why the 5th element COIL shock was developed. Bikes like the bullit and heckler are extreme falling-rate designs, and they use 5th element coils no problem. The key is to adjust the progression by screwing in the air-chamber size adjustment. Smaller chamber = more progressiveness. Larger chamber = more linear of course.

Now if you went to a fox vanilla, romic, or push-modified fox, you wouldn't get the same kind of progressiveness and you would not get adjustable progressivness like the 5th elment coil shock has. To put it simply, the 5th element has adjustable progressiveness, which makes it a perfect shock to mate up with a single pivot bike. Single pivots are either regressive, digressive, or they approach being "linear"(but they never are truely linear). In any of these cases, a progressive 5th element shock that has adjustable progressivness is an excellent pairing.

 

[Jm.]

Digressive, aka falling-rate.

 

[derby]

Digressive, aka falling-rate.

I'll add that the Tomac 6-Shooter's Bradbury design pivot is a lower-medium height pivot. I consider low pivots run from about 1/2 inch above BB to small ring chain line height, medium height pivots run from small ring to middle ring chain height, and high pivots are higher than the middle ring chain line height. The position forward or rearward of the pivot matters a lot too, more rearward pivot located paths tend to be more reactive to travel changes and usually in a good way to better comply the chain-tension reaction to bumps (lowering the pedal kickback or pedal-spin stall feel when hitting bumps). And the deep travel rebound path of a lower-rearward pivot maintains better traction in bumps. Bradbury probably tested a variety of pivot locations and settled on his favorite ride-time feel for the pivot location found on Tomac bikes. It is somewhat close to the Foes pivot location except a little further forward.

Looking at the shock links to the swingarm of the 6-Shooter, it looks like the rate of shock travel movement starts very linear rate near sag, digressing into increasing falling rate as travel compresses. Compared to the Fifth Air the Coil 5th Element should have a little less mushy travel feel in larger bumps without bottoming if the progressive compression adjustment air chamber is firm enough, and it should more completely absorb smaller bumps with even less frame movement. It would be a noticeable improvement when dialed in.

- ray

 

[Poser]

The Ventana El Chamuco has a similar pivot place...

After you explained pivot placement, I went looking at single pivots. Most Ventanas are rear as you favor. The Santa Cruz single pivots and some Cannondale are forward. I think the actual placement of the El Chamuco is similar except Bradbury places the pivot as part of the bottom bracket while the others put the pivot in the downtube. He must like his pivot spot because he used the same placement for the Eli after Tomac discontinuing the Six Shooter. The Tomac 98 is the same as the Foes, also good company.

I do not have much idea what pivot placement really means but I feel better that Sherwood thinks that forward above the bottom bracket is good also. I think that being able to make the pivot part of the bottom bracket i.e. Foes, Titus, other Ventana products makes for a strong pivot point.

Thanks for the education.