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CV/T Goes moto

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Turbo Monkey
Nov 29, 2001
1,889
0
Boston Area
I was watching Dirtrider TV the other night and they did a piece on Progressive and their moto shocks. They have recently introduced the first position sensitive moto shock and it uses CV/T. The Prog guys didn't mention the MTB stuff, but they explained it as working exactly the same as the MTB stuff. They even called it CV/T. They have also introduced a new moto shock that compensates for hot/expanded oil but didn't explain how it worked. I just thought that was cool.

Anyone know Progressive's reputation in the motor world? I know that they are primarily a moto company, but the only other time I have heard of them (non-mtb) has been in magazine ads for custom motorcycles.
 

Kornphlake

Turbo Monkey
Oct 8, 2002
2,632
1
Portland, OR
I talked to johnny at progressive about a year ago about a job opening they had, apparently they filled the position with somebody else in the company... anyways, he mentioned that they were looking into building a bigger version of the 5th element shock for motorcycles, in fact he was anxious to get started on it because he wanted to be a test rider. So it comes as no suprise to me that it's trickled down to moto. What does seem strange is that it hit MTB first, this is the first innovation that has been adapted to MTB first and moto second as far as I know, with the exception of maybe vee brakes.
 

RhinofromWA

Brevity R Us
Aug 16, 2001
4,622
0
Lynnwood, WA
Didn't/Does KTM have a postion sensitive dampening shock for their dirt bikes when they went linkageless back in the late 90's I remember it was reported to not work as well as a linkage/progressive design.

I don't think it was a CV/T thing but it was position sensitive and work like crap.

I wish I had cared more about how the shock worked back then.....:(

I am not suprised abot this technology hitting MTB first. Dirt bikes turn 1000's of RPM's not much pedal maching induced bob there......

It is going to be interesting to see this technology usedin drt bikes though. Will it be as beneficial?

Rhino
 

HTFR

Monkey
Aug 20, 2002
413
0
Chelsea, Quebek
oh i thought this thread was about hondat CVT torque converter transmision. hehe.

i could see a benifet to a "stable" platform on a mx bike. forexample to stop brake dive or to keep the bike level when BRAPPPPPing. but i'm sure that there is just a shim staking technique to do it.
 

RhinofromWA

Brevity R Us
Aug 16, 2001
4,622
0
Lynnwood, WA
I had a hard time finding stuff....

KTM uses a WP PDS shock. Position and speed sensitive shock....:think: but I couldn't find much on KTM or WP site.
 

RhinofromWA

Brevity R Us
Aug 16, 2001
4,622
0
Lynnwood, WA
Why did KTM eliminate the linkage?

My guess - simplicity, less cost (no linkage), easier maintenance, and it's different.

Why does the PDS System use progressive springs?

The lack of a linkage makes the KTM PDS the least progressive of all the popular dirt bikes. To make the ride more progressive the springs MUST be progressively wound. In an effort to make the damping more progressive the WP PDS damping system uses two pistons .


from www.race-tech.com
 

RhinofromWA

Brevity R Us
Aug 16, 2001
4,622
0
Lynnwood, WA
PDS PROGRESSIVE DAMPING SUSPENSION

Yhe KTM & WP PDS suspension system is truly the most advanced suspension system in the world today. Our new Progressive Damping Suspension is the culmination of a partnership between KTM and WP engineers, and years of research.

The heart of the PDS system is the new WP 'Smart Shock', the first shock with a brain. The new smart shock is both speed and position sensitive, thus eliminating the need for heavy, complex linkage designed to provide a rising-rate function.


From http://www.motorsports-network.com/ktm/Ktm.htm
 

ChrisKring

Turbo Monkey
Jan 30, 2002
2,399
6
Grand Haven, MI
KTM eliminated the linkage to reduce weight and to allow air to flow in a straight line from the airbox to the carb. The shock is offset to the side.

I can't wait to get the Sixth Sense Shock (MX 5th Element) for my YZ250F.

Larry: when can I get one? :cool:
 

crashing_sux

Monkey
Jul 17, 2002
311
0
Vancouver, WA
Originally posted by RhinofromWA
PDS PROGRESSIVE DAMPING SUSPENSION

The heart of the PDS system is the new WP 'Smart Shock', the first shock with a brain.

From http://www.motorsports-network.com/ktm/Ktm.htm
I wonder how many "first shocks with a brain" there are? Besides this the Specialized Epic comes to mind as well as an old bike I saw the other day with the old Noleen shock with a computer on it that took batteries and never worked for crap.

I could definitely see benefit in a 5th type shock for MX but I bet they'll remove the platform portion and just use the position sensitive damping. Moto's dont' have pedal bob so giving up small bump performance and traction for the sake of having a stable platform would be silly.
 

Jm_

sled dog's bollocks
Jan 14, 2002
20,067
10,631
AK
Originally posted by crashing_sux
I wonder how many "first shocks with a brain" there are? Besides this the Specialized Epic comes to mind as well as an old bike I saw the other day with the old Noleen shock with a computer on it that took batteries and never worked for crap.

I could definitely see benefit in a 5th type shock for MX but I bet they'll remove the platform portion and just use the position sensitive damping. Moto's dont' have pedal bob so giving up small bump performance and traction for the sake of having a stable platform would be silly.
but we don't know what the effect/benefit of stable valving for turns and G-outs will be...we'll see....
 

crashing_sux

Monkey
Jul 17, 2002
311
0
Vancouver, WA
There have been so many threads on the Honda DH bike that when I first read CV/T goes moto I read it as "Continuously Variable Transmission goes moto" and thought Honda was talking about throwing a beefed up variable tranny in their dirt bikes :D
 

crashing_sux

Monkey
Jul 17, 2002
311
0
Vancouver, WA
Originally posted by Jm_
but we don't know what the effect/benefit of stable valving for turns and G-outs will be...we'll see....
Having your suspension be very active in turns has a very well known effect, it increases your cornering traction. Suspension tuners have spent a lot of time decreasing stiction to improve small bump performance for that very reason.

As for G-outs, the difference will be nothing. You want your suspension to compress in a G-out, you want it to absorb the hit, that's what it's there for. If you set the platform so stiff that your suspension didn't compress through the G-out you'd have horrible small bump performance.

The only reason us mountain biker types want a stable platform shock has been to help pedaling, which just isn't an issue on moto's. Even for DH tuners are starting to offer mods to 5th's and swingers to remove the platform and just keep the position sensitive damping.

That's not to say interesting things won't turn up in testing but it also doesn't mean we need to throw away everything we've learned in the past 50 years of suspension tuning.
 

Jm_

sled dog's bollocks
Jan 14, 2002
20,067
10,631
AK
Originally posted by crashing_sux


As for G-outs, the difference will be nothing. You want your suspension to compress in a G-out, you want it to absorb the hit, that's what it's there for. If you set the platform so stiff that your suspension didn't compress through the G-out you'd have horrible small bump performance.


I don't agree. A romic or similer shock on a G-out pedals like crazy, and you can accellerate like crazy because of this, instead of bog down. It's obviously not the same with a motor bike, but I wouldn't be so quick to judge.

I'm not saying that it's something that they need, but it's something to think about and I wouldn't necessarily write it off, but the position sensitive thing is the bigger picture. That's going to have the most applicability.
 

crashing_sux

Monkey
Jul 17, 2002
311
0
Vancouver, WA
Originally posted by Jm_
I don't agree. A romic or similer shock on a G-out pedals like crazy, and you can accellerate like crazy because of this, instead of bog down. It's obviously not the same with a motor bike, but I wouldn't be so quick to judge.

I'm not saying that it's something that they need, but it's something to think about and I wouldn't necessarily write it off, but the position sensitive thing is the bigger picture. That's going to have the most applicability.
It comes down to the difference between pedaling and twisting the throttle again though. I'm not sure how much you moto but moto's don't have to deal with the complication of us bouncing up and down as power is applied. Since they don't have a deraileur and change chain line either they can (and do) tune the countershaft sprocket location to the swingarm pivot carefully to use accelleration torque to control the rear swingarm, instead of trying to isolate it from the rear shock movement as us bikers do.

They do this mainly to increase traction while accelerating. Just like a drag racing car if you don't have to worry about suspension movement robbing you of power like on a bicycle you can tune that movement to increase your rear wheel traction and help you accelerate.

In a bike suspension is useful but most people would agree that it hampers all out acceleration. Put someone on a DH bike next to a hardtail (or even the same bike with a locked out shock) and all else being equal the guy without suspension movement in the rear is going to accelerate faster. For this situation getting rid of that movement is key.

Put two guys on MX bikes next to each other, one with the rear suspension locked out (where is that lever damnit?) and the other with the suspension working perfectly and the guy with the fully active suspension will accellerate much faster.

Even on pavement this is true.