Rail (625Wh) Knock Block issues possibly?

Bennett59

Member
Apr 15, 2021
24
2
California
I have a trek rail 9.7 had a good wreck on it. Got high sided bent the bars broke the shifter levers off. I got it all back together and new bars. Tight and knock block lined up. When I turn to the right or left it goes till it hits the stops, the forks stop but the handlebars still turn more the fork like few more inches then everything all out of wack again. Is it possible I damaged the knock block?
 

Stihldog

Handheld Power Tool
Subscriber
Jun 10, 2020
3,536
4,953
Coquitlam, BC
I have a trek rail 9.7 had a good wreck on it. Got high sided bent the bars broke the shifter levers off. I got it all back together and new bars. Tight and knock block lined up. When I turn to the right or left it goes till it hits the stops, the forks stop but the handlebars still turn more the fork like few more inches then everything all out of wack again. Is it possible I damaged the knock block?
I wonder if you slightly damaged the knockblock spacer? I think there’s a notch which prevents over-rotation (sacrificial) in the event of a crash. It wouldn’t be obviously noticeable in some cases but could allow further rotation of the bar. ??
 

markloch

Active member
May 14, 2021
186
141
NorCal
"the forks stop but the handlebars still turn more the fork like few more inches "

How can the fork stop and the handlebars keep rotating unless the stem is rotating on the steering tube?
 

Bennett59

Member
Apr 15, 2021
24
2
California
"the forks stop but the handlebars still turn more the fork like few more inches "

How can the fork stop and the handlebars keep rotating unless the stem is rotating on the steering tube?
The stem is moving, but it’s all torqued and tight so I should be moving independently from the forks after full lock
 

Paulquattro

E*POWAH Elite
May 7, 2020
2,307
1,287
The Darkside
Hang on
The stem is moving and the forks are not
that isn't meant to happen if I'm getting what you're saying correctly
The Stem should be clamped tight to the fork steerer, and they move together, if they don't you have an issue with the CSU on the fork or the stem isn't clamping the steering tube.
 

markloch

Active member
May 14, 2021
186
141
NorCal
Hang on
The stem is moving and the forks are not
that isn't meant to happen if I'm getting what you're saying correctly
The Stem should be clamped tight to the fork steerer, and they move together, if they don't you have an issue with the CSU on the fork or the stem isn't clamping the steering tube.

I didn't even think of the CSU and just assumed the stem wasn't properly clamped to the steering tube. I wouldn't be riding that bike until it gets figured out.

To the OP: knock block is supposed to prevent the crown from hitting the frame, no more or no less. No way should the bars be moving independently of the fork, at least not easily.

I put a non-KB stem on my bike using Trek's adapter only to realize that on an XL Rail the crown clears the downtube, no need for the KB.

Has anyone used the adapter? I don't think I'm using it incorrectly, but at 2nm torque it's worse that useless: it doesn't prevent you from over-rotating the handlebars, it just slips (with resistance) when you get to where it's supposed to block.

I've had it where I've unknowingly overturned it one direction (while stationary) and found out the hard way when I turned in the opposite direction while riding and met resistance part way through the turn - very dangerous! I've been meaning to remove KB altogether.
 

irie

E*POWAH Elite World Champion
Subscriber
May 2, 2022
2,572
2,627
Chichester, W.Sussex, UK
I didn't even think of the CSU and just assumed the stem wasn't properly clamped to the steering tube. I wouldn't be riding that bike until it gets figured out.

To the OP: knock block is supposed to prevent the crown from hitting the frame, no more or no less. No way should the bars be moving independently of the fork, at least not easily.

I put a non-KB stem on my bike using Trek's adapter only to realize that on an XL Rail the crown clears the downtube, no need for the KB.

Has anyone used the adapter? I don't think I'm using it incorrectly, but at 2nm torque it's worse that useless: it doesn't prevent you from over-rotating the handlebars, it just slips (with resistance) when you get to where it's supposed to block.

I've had it where I've unknowingly overturned it one direction (while stationary) and found out the hard way when I turned in the opposite direction while riding and met resistance part way through the turn - very dangerous! I've been meaning to remove KB altogether.
Have a KB on my Rail and yes, it's useless. But can't be arsed to take it off.
 

Huckleberry's

Member
Apr 11, 2023
3
4
Medford, OR
I didn't even think of the CSU and just assumed the stem wasn't properly clamped to the steering tube. I wouldn't be riding that bike until it gets figured out.

To the OP: knock block is supposed to prevent the crown from hitting the frame, no more or no less. No way should the bars be moving independently of the fork, at least not easily.

I put a non-KB stem on my bike using Trek's adapter only to realize that on an XL Rail the crown clears the downtube, no need for the KB.

Has anyone used the adapter? I don't think I'm using it incorrectly, but at 2nm torque it's worse that useless: it doesn't prevent you from over-rotating the handlebars, it just slips (with resistance) when you get to where it's supposed to block.

I've had it where I've unknowingly overturned it one direction (while stationary) and found out the hard way when I turned in the opposite direction while riding and met resistance part way through the turn - very dangerous! I've been meaning to remove KB altogether.
Hello Everyone,

I know this is a old post. I just wanted to share a product I designed to displace the stem for the Trek Knock Block. This 2 bolt system gives you excellent strength and holding power to utilize the Trek knock block bearing cap AND allow you to use any stem that fits your steerer tube. Hit me up if you have any questions. Thanks for the interest!

Huckleberry's COC Block:

Huckleberry's COC Block Locking Collar for Trek Knock Block (Knock Block Delete) | eBay

Install Instructions:

 

JC-1

Member
Aug 23, 2021
68
17
New Zealand
Hello Everyone,

I know this is a old post. I just wanted to share a product I designed to displace the stem for the Trek Knock Block. This 2 bolt system gives you excellent strength and holding power to utilize the Trek knock block bearing cap AND allow you to use any stem that fits your steerer tube. Hit me up if you have any questions. Thanks for the interest!

Huckleberry's COC Block:

Huckleberry's COC Block Locking Collar for Trek Knock Block (Knock Block Delete) | eBay

Install Instructions:

I'm confused. How is this deleting the KnockBlock, like the eBay advert says, or bypassing it, like the YouTube video says? It appears to exist to retain the KnockBlock when using an otherwise non-KnockBlock-compatible stem. Much like the Trek KnockBlock Headset Lockring Spacer.
 
Last edited:

Mountainlake

Member
Sep 14, 2023
6
1
France

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