Rail (625Wh) 2022 Trek Rail downtube clearance for Charger 3.1 damper

nickf

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I have Medium size 2022 Rail and have just fitted a Charger 3.1 damper to replace the original Motion Control damper in the Domain fork.

On the Med size Rail the clearance under the downtube is extremely tight if the fork is fully turned (without the knock block fitted) and with the old Motion Control damper this caused some very slight scuffing between the downtube and the compression damper dial. Moreover, the compression dial just slips under the rubber pads on the downtube that are presumably there to prevent this happening!

With the new Charger 3.1 fitted it seems that the compression dials will now make contact with the rubber pad on the downtube. It's likely that this contact will be just enough to potentially damage the fragile dials, but not enough to prevent the fork from turning further under the downtube! However, it does look like the dial should just about avoid contact with the downtube if the fork is turned fully (eg in a washout) crash.

I'd rather avoid damaging the compression dials on my new and expensive damper so I am considering simply removing the rubber pad and hoping that any contact between downtube and compression dial is only trivial.

I guessed that the rubber pads might be attached to the frame via the inside but it appears not. Before I try ripping them off, does anybody know how they are attached? Are they glued on? Has anyone a better solution for this problem?

(BTW I replaced the original knock block system with the after-market Trek knock bloc collar because I fitted a different stem. Although this collar does prevent the fork from excess turning while riding, it isn't tight enough to stop the fork tube over-rotating in the event of a crash. The best I can do is to tighten this collar as much as possible while reducing the tension on the stem/fork tube bolts. The aim being to allow the handlebars to over-rotate during a crash rather than the fork itself.)
 
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I have Medium size 2022 Rail and have just fitted a Charger 3.1 damper to replace the original Motion Control damper in the Domain fork.

On the Med size Rail the clearance under the downtube is extremely tight if the fork is fully turned (without the knock block fitted) and with the old Motion Control damper this caused some very slight scuffing between the downtube and the compression damper dial. Moreover, the compression dial just slips under the rubber pads on the downtube that are presumably there to prevent this happening!

With the new Charger 3.1 fitted it seems that the compression dials will now make contact with the rubber pad on the downtube. It's likely that this contact will be just enough to potentially damage the fragile dials, but not enough to prevent the fork from turning further under the downtube! However, it does look like the dial should just about avoid contact with the downtube if the fork is turned fully (eg in a washout) crash.

I'd rather avoid damaging the compression dials on my new and expensive damper so I am considering simply removing the rubber pad and hoping that any contact between downtube and compression dial is only trivial.

I guessed that the rubber pads might be attached to the frame via the inside but it appears not. Before I try ripping them off, does anybody know how they are attached? Are they glued on? Has anyone a better solution for this problem?

(BTW I replaced the original knock block system with the after-market Trek knock bloc collar because I fitted a different stem. Although this collar does prevent the fork from excess turning while riding, it isn't tight enough to stop the fork tube over-rotating in the event of a crash. The best I can do is to tighten this collar as much as possible while reducing the tension on the stem/fork tube bolts. The aim being to allow the handlebars to over-rotate during a crash rather than the fork itself.)
I have the 2020 medium Rail. Probably similar geometry. I also upgraded to the Lyric Forks (3.1 charger type I think)

The Knock Block system is still important so I use the Bontrager stem with a OneUp carbon bar. The original stem was 60mm and I installed the 45mm stem for a carbon bar which has a larger diameter.

Torque specs for the bar, stem and steering tube are not very high…4nm-8nm. I also used assembly grease for carbon components to help keep the torque specs within tolerances.

One of the rubber bumpers fell off (thankfully in my cave) and I was able to glue it back on. It looked as though it was glued to the paint only. (No screws, no special notch.) The replacement, or extra, knock block parts are available from Trek.

I installed a Kiox on the top tube and that required a new type of holder and the small triangle-shaped retainer for the lower knock block collar. I carefully drilled the two alignment holes required rather than buy and wait for that little part.
 
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