Trek Rail 2020 - Removing / Killing the Knock Block

[davem85]

Hey guys,

I'm about to install a new fork on my 2020 Rail 5 (Fox 38 Performance Elite 170mm). Just test fitted it to check steerer length, forgot to install the Knock Block chip and noticed the new fork not hitting the downtube (anymore?) (by far - there's almost 2-3cm of space).

Is it possible to ditch the Knock Block by just grinding down the chip in the front so it won't interfere with the Knock Block cap anymore? Or am I missing something considering the available free space?

 

[Gyre]

Are you on an XL frame? I think I recall someone saying that XL frames have enough clearance that the knock block isn't needed. On any other size, I'd be surprised if a 38 could clear the downtube all the way around in both directions.

 

[davem85]

Are you on an XL frame? I think I recall someone saying that XL frames have enough clearance that the knock block isn't needed. On any other size, I'd be surprised if a 38 could clear the downtube all the way around in both directions.

It's an XL frame, yes.

Do you know if grinding the chip down will work? Of course I could replace the headset, but since it works perfectly fine and I'll need to put the chip back in anyway, I thought that might be an easy solution.

 

[Doug Stampfer]

I filed off the knock block tab & the only 'problem' I've found is the bars turn 180deg when on the bike rack. I've go a Rail 7 Large. The forks don't hit.

 

[Orangie]

I just used a dremel and cut the chip smaller. Lots more turning radius now. I’m happy

 

[GrandesRoues]

Would it be possible to increase the recess in the ring, rather than filling the chip ?
My idea would be to increase the range while keeping the same amount of metal (same strengh) for the knock block.

 

[davem85]

Would it be possible to increase the recess in the ring, rather than filling the chip ?
My idea would be to increase the range while keeping the same amount of metal (same strengh) for the knock block.

I don't think you're weakening the system cutting or filing down the chip's tab. The Knock Block cap doesn't get touched at all which has direct connection to the headset.

 

[GrandesRoues]

The section (quantity of atoms) holding the 2 parts together will be less if you fill the tab. See :

Knock-Block failed - Trek Rail 9.8 carbon frame damage

Bugger bugger bugger. I had a simple wash-out on a corner at Cwmcarn. Knock-block "feature" broke and the forks over rotated causing the knurled aluminium damper adjuster on the Lyrik's to scrape along the underside of the downtube. Trek are stating it's not a warranty claim which I can't argue...

www.emtbforums.com

It will get weaker.

 

[davem85]

The section (quantity of atoms) holding the 2 parts together will be less if you fill the tab. See :

Knock-Block failed - Trek Rail 9.8 carbon frame damage

Bugger bugger bugger. I had a simple wash-out on a corner at Cwmcarn. Knock-block "feature" broke and the forks over rotated causing the knurled aluminium damper adjuster on the Lyrik's to scrape along the underside of the downtube. Trek are stating it's not a warranty claim which I can't argue...

www.emtbforums.com

It will get weaker.

But that's exactly the part that is cut / filed off anyway. Don't see any weakening in the cap or headset though.

This is how I modified it:

The holes are for the Kiox Knock Block Mount.

 

[GrandesRoues]

ok.
My plan is to keep the knock block, but to get a better range without weakening it.
I will try to dremel the recess a bit further..

 

[davem85]

ok.
My plan is to keep the knock block, but to get a better range without weakening it.
I will try to dremel the recess a bit further..

You could get the Knock Block 2.0 - at least the cap. The range should be a lot better with it.

But why not completely ditch it?
On my other bikes I never felt the need to limit the steering range. When the fork doesn't hit the downtube, I don't see any need on the Rail either.

 

[GrandesRoues]

Knock block can prevent cable pull if the bar turns too much, that's why i want to keep it.
I can't seem to find the 2.0 cap alone. Do you where i could get it (or the mininal group parts) ?

 

[ronianash]

I have a small Rail 7 and have been running without the knock block for over a year. My fork doesn't hit the frame and because of the 29 tyres, I wanted the bigger steering radius.

 

[Richiefromboston]

Ill throw this in here without the knockblock in place my last serious endo crash would have wrecked the frame and pulled wires, I got a sick stem from revolution grips and its knockblock compatible https://revgrips.com/collections/stem/products/revgrips-pro-series-stem. Other than 18wheeler turning radius it works well.

 

[BiGJZ74]

Ill throw this in here without the knockblock in place my last serious endo crash would have wrecked the frame and pulled wires, I got a sick stem from revolution grips and its knockblock compatible https://revgrips.com/collections/stem/products/revgrips-pro-series-stem. Other than 18wheeler turning radius it works well.

That Rev Stem has the recess for the knock block spacer underneath it?

 

[Doug Stampfer]

To make it clear to those contemplating getting rid of the knock block - it is there to stop your forks hitting the downtube- your forks may hit the frame without it. If your forks move easily under the frame without hitting it, then the option is there for removing/ modifying it.

 

[Richiefromboston]

That Rev Stem has the recess for the knock block spacer underneath it?

yes it locks right into place perfectly and they are artwork man, super well made and I smashed it off a boulder first ride no prob loads of colors too and they have a bell or light attachment if you want.

 

[Smittylube]

That stem looks killer. I like the idea of the bell as well

 

[Richiefromboston]

That stem looks killer. I like the idea of the bell as well

Im VERY happy I got it, and I SMASHED IT Going over bars FIRST time I rode with it no probs and its built SUPER well. bell or light mount is swweet and they are Solide dudes.

 

[WNH]

It's an XL frame, yes.

Do you know if grinding the chip down will work? Of course I could replace the headset, but since it works perfectly fine and I'll need to put the chip back in anyway, I thought that might be an easy solution.

Absolutely. Grinding the chip down will work as I have done it. I'm on a large frame with the stock Zeb fork. Plenty of clearance and so happy to be rid of it.

 

[aviserated]

I have a medium Rail 5 and I have plenty of fork clearance using Rock Shoks Zeb fork. No knock block needed. Also have the Industry 9 stem ...no notches machined in stem to accept Treks factory knock block.

 

[LEDDY]

2022 Slash - The knock block feature isn't mandatory so I ground down the tab and sanded the entire piece smooth. They sell a specific chip without the tab, but you have to order through a shop at the moment. I'm surprised it didn't come with the bike, but it was an easy fix. I don't mind the silver contrast with the black. The bars turn a full 360 if needed now. The brakes actually come closer to touching the frame than the fork crown.

The knock block actually bothered me more while I was off the bike, maneuvering it through the house / garage etc. On the bike I didn't mind it at all.

-Sam