Trek Rail with Fox DHX2 coil

Offset

Bushings
Jun 18, 2020
14
29
UK
Thanks Rob!

FYI we also sell shock bushing kits for the rail and have produced many for prior customers. Just note your frame and shock models when ordering this product - Standard Bushings - Pair

Cheers!

Jeron @ Offset
 

davem85

Member
Feb 1, 2021
47
16
Germany
You either need to completely remove and reuse the hardware, including eyelet bushings, from the stock RockShox shock or purchase new kits from FOX for the Bomber CR. If you’re looking to source the FOX kits, the following parts numbers might be useful:

• Upper: 10mm x 54mm 803-03-311
• Lower: 10mm x 40mm 803-03-329

I’d suggest fitting the Bomber CR first without spring so it can be fully compressed with ease, to confirm proper clearance between the piggyback and the downtube. My feeling is there will be contact prior to full compression, but that is only a guess.

Cheers, mate!!
Really useful.

By "including eyelet bushings" you mean, that this is one single part axle and bushing? That's the reason why it wouldn't move?

For my understanding: Outside diameter of this axle-bushing part is somewhat "standard size" and will fit the Bomber's eyelet but the only option to replace the bushing or switch to the "new" bushings is to change all the parts? - Does this also apply to all the spacers or do I reuse these in any case?
 

Offset

Bushings
Jun 18, 2020
14
29
UK
Cheers, mate!!
Really useful.

By "including eyelet bushings" you mean, that this is one single part axle and bushing? That's the reason why it wouldn't move?

For my understanding: Outside diameter of this axle-bushing part is somewhat "standard size" and will fit the Bomber's eyelet but the only option to replace the bushing or switch to the "new" bushings is to change all the parts? - Does this also apply to all the spacers or do I reuse these in any case?

Essentially..

You have the hole at each end of the shock, this is known as the 'shock eyelet'. This will be 15mm in diameter.

Within that, you have a thin bush known as a 'DU bushing', this has an internal diameter of 12.7mm and is a wearable item which stops the actual shock from wearing.

Within that, you have the shock bushing or 'mounting hardware' etc. These come in many different widths depending on the bike. This is what the 54mm / 40mm sizes are and in this case they have a 10mm hole. This is also a wearable item.

Now to explain the spacer and DU bush issue you're having..

There are two types of DU bush, a one piece part which is what we sell DU Bush and a two piece part that comes on Fox shocks amongst some other brands. The two piece part has a lip on either side - this lip then means you need narrower spacers than if you have a DU bush such as ours.

So, if you have a set of spacers that are designed for a one piece DU bush you cannot use them with a Fox two piece DU bush as they are too wide. The same goes for the opposite combination.


Our kits are designed for a one piece DU bush and include spacers to fit this.

Hope that helps chaps!
 

davem85

Member
Feb 1, 2021
47
16
Germany
Essentially..

You have the hole at each end of the shock, this is known as the 'shock eyelet'. This will be 15mm in diameter.

Within that, you have a thin bush known as a 'DU bushing', this has an internal diameter of 12.7mm and is a wearable item which stops the actual shock from wearing.

Within that, you have the shock bushing or 'mounting hardware' etc. These come in many different widths depending on the bike. This is what the 54mm / 40mm sizes are and in this case they have a 10mm hole. This is also a wearable item.

Now to explain the spacer and DU bush issue you're having..

There are two types of DU bush, a one piece part which is what we sell DU Bush and a two piece part that comes on Fox shocks amongst some other brands. The two piece part has a lip on either side - this lip then means you need narrower spacers than if you have a DU bush such as ours.

So, if you have a set of spacers that are designed for a one piece DU bush you cannot use them with a Fox two piece DU bush as they are too wide. The same goes for the opposite combination.


Our kits are designed for a one piece DU bush and include spacers to fit this.

Hope that helps chaps!

Thanks mate!
I think even I got it now ?.

So with the plastic Fox "tool-free" bushings I'd need new spacers. Since top and bottom mounts have different spacers on stock configuration (actually 2x2 on each end) and as far as I can tell the Fox kits only come with one pair of spacers, these won't ever fit.

So with your solution I'd need a pair of standard bushings for my frame, a pair of DU bushes and the tool to get the single old DU bush out, right? Spacers can be reused since space between shock and frame won't change and the stock screw/axle will fit the new bushing's inner diameter so these can be reused as well?

I think I'll go with your product then, great support!

How long does shipping to Germany approximately take in the post Brexit era? ?


Edit:
One more question: When I removed the shock I checked the bearings and noticed the lower ones not rotating smoothly anymore. I can feel some kind of rattle compared to the upper bearings. I think they gotta be replaced. Do you offer any smart solutions to get bearings in and out as well?
 
Last edited:

coregrind

Well-known member
Dec 16, 2020
95
80
BEAVERTON, OREGON USA
Cheers, mate!!
Really useful.

By "including eyelet bushings" you mean, that this is one single part axle and bushing? That's the reason why it wouldn't move?
As expected, @Offset nailed the explanation so I’ve got nothing to add.

And BTW, offsetbushings.com make top notch stuff. I’ve only ever used them once but it was for a special project and were the only solution to make things work for my specific build.
 

Offset

Bushings
Jun 18, 2020
14
29
UK
Thanks mate!
I think even I got it now ?.

So with the plastic Fox "tool-free" bushings I'd need new spacers. Since top and bottom mounts have different spacers on stock configuration (actually 2x2 on each end) and as far as I can tell the Fox kits only come with one pair of spacers, these won't ever fit.

So with your solution I'd need a pair of standard bushings for my frame, a pair of DU bushes and the tool to get the single old DU bush out, right? Spacers can be reused since space between shock and frame won't change and the stock screw/axle will fit the new bushing's inner diameter so these can be reused as well?

I think I'll go with your product then, great support!

How long does shipping to Germany approximately take in the post Brexit era? ?


Edit:
One more question: When I removed the shock I checked the bearings and noticed the lower ones not rotating smoothly anymore. I can feel some kind of rattle compared to the upper bearings. I think they gotta be replaced. Do you offer any smart solutions to get bearings in and out as well?

All correct. Our bushing kits include DU bushes anyway as long as it's for a RS / Fox / etc. standard fitment shock.

EU shipping would usually be a week, but right now we don't have ETA's. International post seems to be being held in customs for safety reasons so it can be a bit of a lottery. I'd recommend going for tracked shipping when ordering at the moment (it's only a few £ more).

As far as removing bearings, you'll want a bearing press tool ideally. You can buy these with various size presses / cups for different setups. Our DU tool is essentially a bearing press with the specific press / cup size for a shock eyelet so you can't go wrong.

Cheers,

Jeron
 

davem85

Member
Feb 1, 2021
47
16
Germany
Just fitted the Bomber CR using masking tape ?.
So here's my update: Shock is a Bomber CR 230x62.5 (65 with 2.5mm spacer), Frame is a Rail 5 2020 XL.

Setup:
20210214_132741.jpg


Compressing (trying to put at least most of my weight onto the bottom out bumper):
20210214_133224(0).gif


Max compression possible (downtube):
20210214_134112.jpg


Max compression possible (bumper):
20210214_134114.jpg


As you can see, the bumber can at least compress 2-3mm more until full bottom out. But there's only about 1mm left before hitting the downtube.

Considering the shock is mounted using slightly compressable tape, I think it actually sits 0.5-1mm higher with this test setup as it would with more trail oriented bushings.

A Bomber CR with 60mm of stroke might fit using a progressive spring, but the 62.5 definitely doesn't.

Any ideas how to travel down with these shocks?
 

Doomanic

🛠️Wrecker🛠️
Patreon
Founding Member
Jan 21, 2018
8,724
10,389
UK
Get a nylon washer of the required thickness and cut a slot in it so it will flex enough to pop onto the shaft. Fit below the rubber bump stop.
 

davem85

Member
Feb 1, 2021
47
16
Germany
The lower spring seat isn’t in place on the shock. That will likely move the bottom out bumper up the shaft and may provide the addition space needed at the downtube. Give it a try with the spring seat installed.

Unfortunately this has no effect.
The lower spring seat has a larger inner diameter and doesn't sit directly on the shock shaft.

Lowest position without lower spring seat.
20210214_171507.jpg


Lower spring seat installed:
20210214_171526.jpg
20210214_171544.jpg


Anyone knows how much the bottom out bumpers can get compressed? I think a nylon washer could be worth a try but I obviously don't wanna lose too much travel. As far as I know there ist only a 65mm stroke Bomber CR and all less travel versions have external spacers / washers anyway. There is already one washer in place to get from 65 to 62.5. Just adding another one sounds like it should work just fine.
 
Last edited:

Doomanic

🛠️Wrecker🛠️
Patreon
Founding Member
Jan 21, 2018
8,724
10,389
UK
That's exactly what Sprung Suspension said they'd do to limit travel on my Powerfly when I was test fitting a coil on that.
 

davem85

Member
Feb 1, 2021
47
16
Germany
Anyone replaced the lower shock bearings yet?

They definitely need to be replaced on my Rail 5 - currenty getting in the axle needs a lot of force, which can't be right. Should slight right in, I suppose (that's what she said).
Tried to find a suitable tool but I guess it won't be that easy because of the frame's shape around those bearing seats.
 

magic82

Member
Nov 18, 2020
13
2
italy
I have bought a Fox DHX2 2018 for my trek rail 9 alluminium, I have a question now:

which hardaware kit bushing need?

these parts are OK
• Upper: 10mm x 54mm 803-03-311
• Lower: 10mm x 40mm 803-03-329

Could you help to me?

Thanks
 

coregrind

Well-known member
Dec 16, 2020
95
80
BEAVERTON, OREGON USA
I have bought a Fox DHX2 2018 for my trek rail 9 alluminium, I have a question now:

which hardaware kit bushing need?

these parts are OK
• Upper: 10mm x 54mm 803-03-311
• Lower: 10mm x 40mm 803-03-329

Could you help to me?

Thanks
Yes...these are the FOX part numbers for the traditional eyelet type shock mounts that fit the Rail.
If your Rail originally came with the trunnion type shock, you’ll also need these items from Trek:
• upper axle - 599898
• lower axle - 599900

C0CE30DC-B422-4DCE-9855-A5D06EDBD60D.jpeg
 

davem85

Member
Feb 1, 2021
47
16
Germany
Yes...these are the FOX part numbers for the traditional eyelet type shock mounts that fit the Rail.
If your Rail originally came with the trunnion type shock, you’ll also need these items from Trek:
• upper axle - 599898
• lower axle - 599900

View attachment 53752

If I got Offset Bushing's post right, you would have to replace the 2-part yellowish bushings with standard bushings in order to reuse the spacers on the Rail. Not sure if you can get these in different sizes anywhere.

Offset's kit costs roughly the same or a little less, that's why I ordered from them.
edit: And because of the great support of course.
 

Stray cat

Well-known member
Aug 24, 2018
189
143
On the trails
Yes...these are the FOX part numbers for the traditional eyelet type shock mounts that fit the Rail.
If your Rail originally came with the trunnion type shock, you’ll also need these items from Trek:
• upper axle - 599898
• lower axle - 599900

View attachment 53752

Hi. I’d like to mount a Fox DPX2 on a Rail 7,standard shock mount. Can’t find Fox hardware. Would it be this right? Thanks

IMG_0365.jpg
 

coregrind

Well-known member
Dec 16, 2020
95
80
BEAVERTON, OREGON USA
Ok. I thought someone said,Fox and Rock Shox hardware were compatible.
Sure, RockShox hardware can be used in a FOX shock, with the addition of eyelet bushings being required items to make it compatible. Beyond that, the kit you’ve referenced is for a Session frame that has an offset design; the Rail does NOT use an offset.
 

magic82

Member
Nov 18, 2020
13
2
italy
Sure, RockShox hardware can be used in a FOX shock, with the addition of eyelet bushings being required items to make it compatible. Beyond that, the kit you’ve referenced is for a Session frame that has an offset design; the Rail does NOT use an offset.
Hi Coregrind,
Are you sure that the rail does not use an offset? I ask this because my rear shock in the bottom side have offset
 

coregrind

Well-known member
Dec 16, 2020
95
80
BEAVERTON, OREGON USA
Hi Coregrind,
Are you sure that the rail does not use an offset? I ask this because my rear shock in the bottom side have offset
I have experience with shock fitting on the carbon Rail frame. It is not offset. For the aluminum frame, it’s been suggested previously that it is also not offset.
The shock on my non-Trunnion Rail 7 is not offset. I am absolutely certain of this, not only because I've looked, but because I have changed the shock and had to modify the spacers which involved using a vernier.
 

Hob Nob

Active member
Jun 4, 2020
152
149
UK
What stroke DHX2 did you run? I'm looking to run a 230x65mm. I currently have a 230x65mm DPX2 installed but want to run Coil like my regular bikes

Depends. Pre '21 MY shocks I don't think you will fit anything longer than the stock 57.5mm as the piggyback is really long. I tried one with a bit of tape to test for marks & it 'just' kissed on a hard bottom out.

Float X2 '21 MY fits in 230x60, as the piggyback is shorter (but fatter so potentially contacts higher up the downtube). I would say it has ~2mm spare on hard bottom out. I wouldn't think you will get anything bigger on there.

All on a large frame for reference.
 

BiGJZ74

E*POWAH Master
Subscriber
Mar 17, 2021
573
444
American Canyon, CA
Depends. Pre '21 MY shocks I don't think you will fit anything longer than the stock 57.5mm as the piggyback is really long. I tried one with a bit of tape to test for marks & it 'just' kissed on a hard bottom out.

Float X2 '21 MY fits in 230x60, as the piggyback is shorter (but fatter so potentially contacts higher up the downtube). I would say it has ~2mm spare on hard bottom out. I wouldn't think you will get anything bigger on there.

All on a large frame for reference.
I was definitely looking for a 2021but hoping 65mm would fit. I guess i'll stick with my 230x65 DPX2 for now. Thanks for the info
 

Doomanic

🛠️Wrecker🛠️
Patreon
Founding Member
Jan 21, 2018
8,724
10,389
UK
DVO Jade X with 60mm stroke fits a medium Rail with plenty of room to spare. I’m going to get a 62.5 or 65 spring cup to try soon.
 

Jerma

Member
Mar 29, 2021
14
19
Finland
Anyone have experience on the EXT Arma V3 coil shock (EXT ARMA HBC V3 - DOWNHILL RACING - Extreme Racing Shox) on a Trek Rail Large ?

Looking to swap out the original air to either Öhlins TTX22M or the EXT Arma V3.

I'v seen the comments on this thread that both would fit fine, but the EXT Storia V3 would need modification (swap the smaller piggybag from the Arma)? Would this apply to the Arma V3 as well if selecting the stock 230x57,5mm version ? The Arma seems to have a smaller arm to the piggypag due to different structure.

And then there is the discussion of what spring to choose based on OD. I know I need 550 and 600Lbs springs... What OD will fit the Rail ? And what spring manufacturers would be OK ?

Help would be appreciated.

Details for EXT products (coil shocks and springs):

Here is the diagram for the EXT Storia V3: http://www.extremeshox.com/wp-content/uploads/2019/06/MD0007-A_STORIA_V3.pdf

And here the diagram for the EXT Arma V3: http://www.extremeshox.com/wp-content/uploads/2019/06/MD0008-A_ARMA_V3.pdf

EXT spring rates: http://www.extremeshox.com/wp-content/uploads/2017/06/EXT-SPRING-2017.pdf
Suitable springs for Rail (EXT 117), stroke length between 51mm - 63,5mm has OD of 56mm (according to the Finland re-seller).

Note from EXT Sales department:
Thank you for the question. We NEVER mounted our shock on Trek Rail. The problem comes from piggyback-frame incompatibility. So at the moment our shock doesn't fit the Rail.
Best regards - Cordiali saluti
Sales department - Ufficio Commerciale
Details for Öhlins products (mainly TTX22 series shocks and suitable springs)

Öhlins spring 180-77-XX (fits the TTX22 series shocks), stroke length 57mm - 67mm. OD 55-56mm (according to the Finland re-seller).

Jerma.
 
Last edited:

EMTB Forums

Since 2018

The World's largest electric mountain bike community.

554K
Messages
28,010
Members
Join Our Community

Latest articles


Top