# Delta System rear suspension. Anyone curious, and What is it?



## Aust95 (Apr 24, 2008)

I recently saw some press about Evil's new prototype trail bike called the Sect. It has the Delta System rear suspension, and I just learned that it was another design by the big Dave Weagle. We all know all the talk about the DW rear in the Turners, Ibis, and Pivots. But Delta System? Seems much more obscure to me, and I wasn't sure exactly which forum to ask this, but the Evil Revolt, their downhill frame, has this suspension and now there are prototypes of 140mm and 160mm travel frames, the latter is supposed to be a mini-DH rig/trail bike.

Can anyone enlighten me as to what the difference is between DW link and Delta System? And has anyone here ridden the Delta System? Is it like DW link?


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## Fix the Spade (Aug 4, 2008)

Delta is a linkage driven single pivot. DW link is a short link four bar system. 

The most obvious difference I can see from other single pivot designs is that the linkages drive the front of the shock (as opposed to the back on roughly similar designs from Commencal/Morewood), whilst the shock itself is mounted on the swimgarm at the back, so it's floating (which seems to be the in gimmick at the moment).

Looking at the way it works the link drives the shock towards the swingarm rather than away from it Trek style. I assume this would have an efect similar to the floating shock on Pace bikes, where it apes a shorter stroke shock for the given travel. Quite what benefits that's supposed to have is best left answered by Weagle himself (I'm not being pedantic, I really don't know).

As far as axle path it can be treated as a mid height single pivot. In fact the axle path is nearly identical to a Commencal Supreme DH (the current one).

I haven't ridden it so this is probably crap, but I imagine it's riding feel would be not far off bikes like the Commencal Supreme DH, Morewood Makulu. Probably more progressive in it's feel and harder to bottom out, but that's just guessing.


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## mountain_yj (May 18, 2009)

http://www.pinkbike.com/video/71534/

Found this little clip. I think with delta it's based more around that triangle that compresses the shock. It looks like there is a little link down by the BB to though. Looks like it could be the lower shock mount. But as the rear tri pivots up it pulls down on a little link that pulls the tri at the front shock mount compressing the shock.


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## davec113 (May 31, 2006)

As other said, its a single pivot, the linkage is to control the leverage curve of the shock as it goes through it's travel. Being single pivot, the axle path is the same as any other bike with a similar pivot location.

It holds the shock way down low and looks pretty slick, the benefits of the leverage manipulation could be substantial (IDK, never rode an Evil...). As I see it, the tradeoff of this type of linkage vs the typical linkage-driven single pivot (Kona, Turner, Trek, etc... ) is the seatstay linkage on the typical bike also stiffens the rear end, or at least the opportunity is there. Bikes like the dhr, supreme dh, evil, etc. must compensate for the lack of seatstay pivot by beefing up the main pivot and swingarm.


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## davep (Mar 11, 2005)

Couple key points about the Delta system

Floating shock. This moves high load areas away from frame tubing (that could otherwise be thinner/lighter) and toward places that are already heavily loadede and more durable like kinkages and pivots. It allows a frame to be built slightly lighter if this is taken into consideration. This design also compresses the shock from both ends, allowing more varaition in the shock/wheel rate through the travel.

The real issue with this frame is the ability to adjust travel WITHOUT any change to the above mentioned rate. As most know, DW has a pretty good idea and is very precise about the force (braking, traction, chain torque, mass transfer, etc) interactions of his frames to create what he feels is the ideal ballance for the intended use. Change in the shock/wheel rate would change this ballance and make the bike ride different in different geometry settings. Any and all previous adjustable geometry frames have had this issue. Changes in geometry change the wheel rate and dynamics of the bike. So the bike is designed as some sort of comprimise of the two (or more) geometry positions.

The Delta system mantains a constant wheel/shock rate as you change the geometry, so the bike always has the same dynamics that were intended/designed.

Pivot height, low shock/COM and the adjustable head angle sleeve are not part of the DELTA IIRC, but are also well thought out, nice features.

Read the 'tech crap' section of the evil bikes web site.


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## Aust95 (Apr 24, 2008)

Props for the good info guys! I read each of your posts over at least twice with my eyes glued to the writing to suck all the relevant info out of the words. Thanks! The video helped me see the suspension in action--I call this an atypical single pivot.

I wonder how all this translates into performance...


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## davep (Mar 11, 2005)

some info/consumer feedback on the Revolt:
http://www.ridemonkey.com/forums/showthread.php?t=217165

info about the 140mm travel frame and possible other longer travel versions:
http://www.ridemonkey.com/forums/showthread.php?t=223853&highlight=evil+revolt


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