Trek Rail with Fox DHX2 coil

zaykay

Member
Dec 3, 2019
93
79
Finland
Got finally the mounting hw for my coil shock. Two alternatives to install DHX2, either use 10 x 40 and 10 x 54 Fox mounting kits or press 12,7mm du bushings and use the stock shocks mounting hw. Both will work.
189B6768-CABB-4F13-8323-C3D03A078132.jpeg
 

dochabanero

Well-known member
Sep 8, 2019
193
187
Sweden
Let us know how you like it once you’ve done a few rides. Guessing you do mostly gravity oriented riding?
 

zaykay

Member
Dec 3, 2019
93
79
Finland
Not really. I’m coming from Meta Power with a coil shock and have coil also in my V4 Nomad. I just prefer plush ride and feel that stock shock is the weakest part of the bike.
 

Doomanic

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Interested to hear how you get on. Is that a Rail 7?
 

zaykay

Member
Dec 3, 2019
93
79
Finland
Interested to hear how you get on. Is that a Rail 7?
Yes, I think Rail 7 is the best platform for upgrades. I have added also Charger 2.1 RC2 damper and SKF Seals to fork which makes it basically a Lyrik Ultimate with stiffer EMTB crown :)
 

Good Times

Member
Nov 8, 2019
101
84
Sydney Australia
Oooohhhhh thank you for this. I was about to research the re:Aktiv as a replacement shock as I thought clearance on the seat tube wouldn’t allow for a coil. Which I’d much prefer! Wonder if I could get a DVO Jade in there?

Also contemplating the fork cartridge upgrade.
 

Good Times

Member
Nov 8, 2019
101
84
Sydney Australia
Do you know the OD of the coil? I'm looking at one with a 52.65mm OD (550lb) or 54.5mm (600lb). From a quick measure I've got around 56mm to play with but not sure if clearance reduces through the travel. (Large frame BTW)
 

zaykay

Member
Dec 3, 2019
93
79
Finland
Do you know the OD of the coil? I'm looking at one with a 52.65mm OD (550lb) or 54.5mm (600lb). From a quick measure I've got around 56mm to play with but not sure if clearance reduces through the travel. (Large frame BTW)
Shock bends forward in compression. So it’s closest to saddle tube when fully extended. My frame is also Large and I’m using Nukeproof Superlight Steel Enduro spring. I think it has and OD of 57,5mm. I know that Fox SLS springs have smallest OD if you want to play safe.
 

zaykay

Member
Dec 3, 2019
93
79
Finland
Plenty of progression. I would not go back to air. Stock reActiv shock feels like it has really open bleed, so linkage needs a lot of progression. I test rode Rail 9 before buying 7. I think stock shock on rail (basic super deluxe rt) has a lot more platform than reActiv has. I don't think the reActiv shock works really that well in fast and steep dh style of riding.
 

smuts

Member
May 3, 2020
11
16
Switzerland
I‘ve been considering a dhx2 for my rail too. @zaykay what tune is your dhx2 And how did you go about determining which one to use? Rider weight & spring rate?
 

Doomanic

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Shock is 230 x 60 metric and this gives 156mm rear wheel travel. Checked without a spring that there’s enough clearance for added travel.
How much space is there between the back of the seat tube and the linkage on full compression?
 

zaykay

Member
Dec 3, 2019
93
79
Finland
I‘ve been considering a dhx2 for my rail too. @zaykay what tune is your dhx2 And how did you go about determining which one to use? Rider weight & spring rate?
I don’t think there are different DHX2 tunes if you just buy a shock. Same year models will come with the same tune and you just fine tune it with clickers. If it is taken from a bike some manufacturers get special tunes from Fox. Mine is off the shelf 2018 DHX2 from Tftuned.

I’m 80kg’s and run 475lbs spring. Could go also 500lbs spring I think.
 

zaykay

Member
Dec 3, 2019
93
79
Finland
How much space is there between the back of the seat tube and the linkage on full compression?
I did not measure this, but enough. Mine is Large frame, smaller frames might not have enough space for DHX2. Lower spring seat hitting the downtube is the most problematic measure. In smaller frames that is the area where it might get too tight.
 

Doomanic

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Yeah, I know about the reservoir hitting the downtube on Medium and Small frames, It's the gap at the back I'm thinking about.
 

woody1990

New Member
May 19, 2020
3
2
Guisborough
Has anyone fitted a DPX2 to a Trek Rail 9? Wondering if I would just need the same size mounts as you used zaykay? The Rockshox rear shock failed after 3 rides. Loosing air and leaking oil.
 

Doomanic

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Are you sure?
Not any more.

Looks like the aluminium Rails are conventional and the carbon Rails are Trunnion.

EDIT: The Rail 9 is also Trunnion, it must have something to do with Trek's RE:aktiv with Thru Shaft damper that the higher spec bikes run.
 

Stray cat

Well-known member
Aug 24, 2018
189
143
On the trails
Not any more.

Looks like the aluminium Rails are conventional and the carbon Rails are Trunnion.

EDIT: The Rail 9 is also Trunnion, it must have something to do with Trek's RE:aktiv with Thru Shaft damper that the higher spec bikes run.

It’s curious. Linkage looks like the same on 9.8 and alloy ones. I understand you could set both, Trunnion and regular one.
Good question for Trek.
 

Doomanic

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The Trek website shows them as the same eye to eye and stroke, so I'm not sure what the deal is.
 

Stanpipe

Active member
Jun 12, 2020
79
80
Isle of Wight - UK
I think the ReAktiv shocks are a lot wider/stronger at the base therefore the mounting points are spaced further apart. The thrushaft refers to the shaft coming through the bottom of the shock as it compresses.
 

Stray cat

Well-known member
Aug 24, 2018
189
143
On the trails
Another thing. Is really worth the RockShox Deluxe RT3, DebonAir, RE:aktiv stock shock or better a standard Super Deluxe Ultimate or Fox DPX2?
 

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