Unfortunately DMS is out of business but a lot of their suspension are still in use. This page tries to gather as much information as possible to help people maintain their DMS suspension.
There are different kinds of DMS coilovers, some with 40mm inserts and others with 50mm inserts. Most of the information on this page relates to the DMS 50mm gravel coilovers.
The video below will walk you through the install of DMS 50mm coilovers on an 04 Subaru STi.
We also recommend using socks/covers to protect the coilovers from dirt/sand/water that can produce corrosion or damage seals. We recommend using SealSavers ProSeries Coil Savers size 2.0-2.5 (see video below). they come in pair so you will need 2 to cover the 4 shocks. You can find them at https://sealsavers.com/product/proseries-coil-savers/
The Outerwears sock covers don't really hold up do rally duty (for DMS shocks use https://www.amazon.com/gp/product/B003TPYUQI).
Redline CV-2 wheel bearing grease
Seals: SKF 19590
Bushings: SKF PCM 505540 M
Bump stops can be sourced from http://resuspension.com/
New strut bodies: check with Fercomp USA, Samsonas strut bodies will fit DMS 50mm inserts
New inserts: pretty much any 50mm inserts should fit (Bilstein, Samsonas, etc...)
Info from Josh Armantrout:
"The bushings are 5040DU garlock bushings (motion industries part number: 03783530). The seals are International Seal 50 X 58 X 4 VG NBR SEAL (motion industries part number: 00604546)."
Kelly Motorsport in Ireland appears to be the last distributor that is still actively servicing DMS. This is their FB page, which has all of their other contact info: https://www.facebook.com/KellyMotorsportRallying/
They are set up to rebuild inserts, still have some stock of some inserts and components, and are working with suppliers to see about having replacements manufactured.
Regular maintenance is key, usually just an annual regrease and seal inspection is enough as shown in the following video.
When you start to observe some play in the coilover, the first cause might be the strut housing unthreading from the bottom mount (see next video).
After a while the bushings inside the strut body will wear and will cause some play between the insert and the housing. The video below walks you through the bushing replacement procedure:
Reading the spring rates
(information from https://www.rallyanarchy.com/phorum/read.php?5,17645,page=2)
Four types of spring winds:
KST (tarmac, or when ride height is needed)
MG (street, tarmac)
DP (gravel, some street)
General guidelines, not written in stone.
DSP = DMS SPRING
225 = SPRING RATING
DP = TYPE of WIND
350 = spring length
FL = FREE LENGTH OF SPRING (goes with 350)
ALSO can have something like this
Numbers mean the same thing, different order.
More info from Josh Armantrout:
The ID numbers on the inserts will look something like this:
DMS SUB F
NG2 TYPE 190303
The first line is the brand and then SUB F indicates a front and SUB R indicates a rear.
On the second line, the first sequence are the fitment. "NG TYPE" = Subaru Gc and "NG2 TYPE" = Subaru GD. The last section is the date code, in that example it was manufactured on March 3rd, 2019.
Then the third line is a serial number.
A note about inserts
GC and GD rear inserts are different (see pic above) and GC inserts won't fit in a GD top hat.
The front inserts have a collar at the bottom (see pic below)
The adjusters for bump and rebound at the bottom of the strut tend to rub on the axle boots in the front and are very exposed in the rear. We recommend to remove them after you are done with adjustment (just unscrew the rebound nut with a 7mm wrench). If you lost your adjuster, you can adjust bump with what a 3mm allen/hex. For rebound you'll have to screw in an M5x0.8 bolt to rotate the shaft that does rebound adjustment (you'll need to know where 0 is, it's laser etched on the shaft of the insert. (see servicing video in the page above)