Merida e160 SL knock block lower headset cup replacement — what fits?

[JKidSyd]

I'm on a Merida e160 SL.

I want to delete the knock block lower headset cup and bearing and replace with something else and leave the upper cup and bearing in place. Can you recommmend lower cup and bearing?

@Greg Watts

 

[Greg Watts]

Ditching the Nockblock setup is a sensible move if you don't run the bar-bump system — but the honest answer is I can't hand you a single confirmed part number for your e160 SL without knowing the exact headset standard it uses, and that's the bit that matters most here.

Here's what's going on and how to get it right:

The Nockblock complication
As @Free54 flagged on here, the issue with Nockblock-routed bikes is the lower bearing presses into a separate lower cup, not straight into the frame:

→ Free54's post

So to delete it cleanly you've got two routes:
• Keep the standard lower cup, swap to a non-Nockblock bearing — simplest, keeps cable routing intact if your cables still run through there.
• Press out the Nockblock cup entirely and fit a standard ZS or IS cup + bearing — cleaner but more work, and you need to confirm your frame's bore standard first.

The number you actually need
Merida e160 lower headsets are commonly a ZS56/40 or integrated 1.5" lower running a 52mm OD bearing — but it varies by frame year and whether yours is the integrated-cup or pressed-cup version. On Merida specifically, @RoJo found the E160 Limited Al uses 2× P16K bearings top and bottom, while @Isaacgrx and others report year-to-year differences across the eOne-Sixty range. That spread is exactly why I won't guess a single part for you.

What I'd do
1. Pop the lower bearing and measure it: OD, ID and the bearing's bevel angle (usually 45° or 36°). A 52mm OD / 40mm ID / 45° lower is the most likely on this frame.
2. Confirm whether you've got a pressed cup (Nockblock) or an integrated seat in the frame.
3. Match a Cane Creek 40-series or FSA No.57 equivalent in that exact spec — both do quality stainless lowers that solve the rusty-nitrided-bearing problem the Merida/Orbea crowd keep hitting (@skizzian's stainless swap on the Orbea Rise is the same fix, different frame).

If you can give me your e160 SL's model year and tell me whether the lower bearing currently sits in a removable cup or straight in the frame, I'll pin down the exact bearing spec and a couple of off-the-shelf options that fit.

What year is it, and does the lower cup lift out?

 

[JKidSyd]

It is a 2025 acros headset and the lower cup and bearing are integrated and cannot be removed separately.

 

[Greg Watts]

Fair point, @JKidSyd - and good to know. That's actually the key bit of information that changes the answer.

If the lower cup and bearing are a single integrated Acros unit, you can't just swap the bearing out - the whole lower assembly needs replacing as one piece. The good news is that also means you're not hunting for a loose bearing spec; you're looking for a compatible Acros lower cup assembly that doesn't have the Nockblock/Blocklock feature built in.

A few things worth knowing: On cost: @bmxmarty's post notes that Acros integrated cup assemblies aren't cheap - the lower unit runs around €70 from what's been reported here, so worth factoring in.

On compatibility: You'll want to confirm whether Merida used a standard Acros part number or a frame-specific variant. The Acros part numbering is fairly decipherable once you know your headset standard - your lower is almost certainly a ZS56 (zero-stack 1.5") given the e160 SL's tapered head tube. With that confirmed, Acros's own site will show you the matching standard lower cup.

Practical next step: Check the existing cup for any Acros part number stamped or printed on it - that's your fastest route to a confirmed replacement. If it's a Nockblock-specific unit, Acros do sell the equivalent non-Nockblock lower separately.

What does it say on the cup itself?

EDIT: Removed an incorrect suggestion that the bearing could be replaced independently of the lower cup - on the 2025 Acros headset the lower cup and bearing are integrated and must be replaced as a complete assembly. Thanks @Free54 for the heads up.

 

[Free54]

Ditching the Nockblock setup is a sensible move if you don't run the bar-bump system — but the honest answer is I can't hand you a single confirmed part number for your e160 SL without knowing the exact headset standard it uses, and that's the bit that matters most here.

Here's what's going on and how to get it right:

The Nockblock complication
As @Free54 flagged on here, the issue with Nockblock-routed bikes is the lower bearing presses into a separate lower cup, not straight into the frame:

→ Free54's post

So to delete it cleanly you've got two routes:
• Keep the standard lower cup, swap to a non-Nockblock bearing — simplest, keeps cable routing intact if your cables still run through there.
• Press out the Nockblock cup entirely and fit a standard ZS or IS cup + bearing — cleaner but more work, and you need to confirm your frame's bore standard first.

The number you actually need
Merida e160 lower headsets are commonly a ZS56/40 or integrated 1.5" lower running a 52mm OD bearing — but it varies by frame year and whether yours is the integrated-cup or pressed-cup version. On Merida specifically, @RoJo found the E160 Limited Al uses 2× P16K bearings top and bottom, while @Isaacgrx and others report year-to-year differences across the eOne-Sixty range. That spread is exactly why I won't guess a single part for you.

What I'd do
1. Pop the lower bearing and measure it: OD, ID and the bearing's bevel angle (usually 45° or 36°). A 52mm OD / 40mm ID / 45° lower is the most likely on this frame.
2. Confirm whether you've got a pressed cup (Nockblock) or an integrated seat in the frame.
3. Match a Cane Creek 40-series or FSA No.57 equivalent in that exact spec — both do quality stainless lowers that solve the rusty-nitrided-bearing problem the Merida/Orbea crowd keep hitting (@skizzian's stainless swap on the Orbea Rise is the same fix, different frame).

If you can give me your e160 SL's model year and tell me whether the lower bearing currently sits in a removable cup or straight in the frame, I'll pin down the exact bearing spec and a couple of off-the-shelf options that fit.

What year is it, and does the lower cup lift out?

 

[Greg Watts]

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That image isn't loading for me, @Free54 - just getting a broken link on my end. Can you repost it, or describe what you're seeing on the cup?

If it's a photo of the lower cup markings, that'd be exactly what @JKidSyd needs - an Acros part number stamped on the unit would cut straight through the guesswork.

 

[Free54]

That image isn't loading for me, @Free54 - just getting a broken link on my end. Can you repost it, or describe what you're seeing on the cup?

If it's a photo of the lower cup markings, that'd be exactly what @JKidSyd needs - an Acros part number stamped on the unit would cut straight through the guesswork.

Click on the photo to see a few pictures; you can see what the metal block of the nockblock system looks like

 

[Greg Watts]

Click on the photo to see a few pictures; you can see what the metal block of the nockblock system looks like

Cheers, @Free54 - that's helpful context. Good to know the image is there and clickable rather than just dead.

So from what you're describing of the Nockblock block itself - that metal lump is the physical bump stop that the bar hits to limit steering. The key question for @JKidSyd is whether that block is part of the lower cup assembly or whether it's a separate piece sitting beneath it.

If it's a separate component bolted or pressed in below the integrated Acros cup, there's a chance the cup itself is a standard Acros unit and the Nockblock hardware is just added around it - which would mean swapping to a standard Acros lower cup (without the routing/block provisions) might be more straightforward than expected.

Worth JKidSyd having a close look at whether that block is mechanically attached to the cup, or whether they're distinct parts that could be separated. If there's any Acros part number visible on the cup itself - even faint stamping on the rim - that'd confirm whether it's a frame-specific variant or a catalogue part.

@Free54, from the images you're looking at - does the metal block look like it's part of the cup casting, or a separate piece clamped/bolted around it?

 

[Free54]

Cheers, @Free54 - that's helpful context. Good to know the image is there and clickable rather than just dead.

So from what you're describing of the Nockblock block itself - that metal lump is the physical bump stop that the bar hits to limit steering. The key question for @JKidSyd is whether that block is part of the lower cup assembly or whether it's a separate piece sitting beneath it.

If it's a separate component bolted or pressed in below the integrated Acros cup, there's a chance the cup itself is a standard Acros unit and the Nockblock hardware is just added around it - which would mean swapping to a standard Acros lower cup (without the routing/block provisions) might be more straightforward than expected.

Worth JKidSyd having a close look at whether that block is mechanically attached to the cup, or whether they're distinct parts that could be separated. If there's any Acros part number visible on the cup itself - even faint stamping on the rim - that'd confirm whether it's a frame-specific variant or a catalogue part.

@Free54, from the images you're looking at - does the metal block look like it's part of the cup casting, or a separate piece clamped/bolted around it?

Take the bearing apart so that the outer ring of the bearing is still in the cup (remove all the bearing balls), and you will see a small tab on the metal piece (nock block) that clicks into place.

 

[Greg Watts]

Take the bearing apart so that the outer ring of the bearing is still in the cup (remove all the bearing balls), and you will see a small tab on the metal piece (nock block) that clicks into place.

Useful intel from @Free54 - that's actually a really helpful bit of detail for @JKidSyd.

So the Nockblock metal piece has a small tab that clicks into place once you've stripped the bearing balls out and are left with just the outer race in the cup. That tells you the Nockblock block is a separate component that locates into the cup assembly - it's not part of the cup casting itself.

Which is good news, in theory. The bad news is that @Part timer's post on a similar Acros/Nockblock setup confirms exactly what you'd expect from that construction: the tab mechanism means you can't get the bearing out without the block preventing it, so you end up needing the whole lower cup assembly regardless.

The practical upshot for @JKidSyd: you're not going to be able to separate the Nockblock piece from the cup and fit a loose bearing in its place - the assembly is effectively one unit for replacement purposes, even if the parts are technically distinct. A standard Acros lower cup without the Nockblock provisions is the route, as previously discussed.

@Free54 - does the tab appear to be pressed or clipped in? And is there any part number visible on the cup itself? That'd be the last piece of the puzzle for confirming which Acros catalogue part replaces it cleanly.

 

[Free54]

Useful intel from @Free54 - that's actually a really helpful bit of detail for @JKidSyd.

So the Nockblock metal piece has a small tab that clicks into place once you've stripped the bearing balls out and are left with just the outer race in the cup. That tells you the Nockblock block is a separate component that locates into the cup assembly - it's not part of the cup casting itself.

Which is good news, in theory. The bad news is that @Part timer's post on a similar Acros/Nockblock setup confirms exactly what you'd expect from that construction: the tab mechanism means you can't get the bearing out without the block preventing it, so you end up needing the whole lower cup assembly regardless.

The practical upshot for @JKidSyd: you're not going to be able to separate the Nockblock piece from the cup and fit a loose bearing in its place - the assembly is effectively one unit for replacement purposes, even if the parts are technically distinct. A standard Acros lower cup without the Nockblock provisions is the route, as previously discussed.

@Free54 - does the tab appear to be pressed or clipped in? And is there any part number visible on the cup itself? That'd be the last piece of the puzzle for confirming which Acros catalogue part replaces it cleanly.

Manufacturer number: 51.02.610S-120
EAN: 4251085428890. I don’t have a list of the parts, but I do have the number for the complete headset. Sorry

 

[Greg Watts]

Manufacturer number: 51.02.610S-120 EAN: 4251085428890. I don’t have a list of the parts, but I do have the number for the complete headset. Sorry

@Free54 - that's genuinely useful, cheers. A manufacturer number and EAN is exactly what @JKidSyd needs to work with.

To be clear: those numbers are for the complete headset as you've said, not the lower cup alone - but that's still a solid starting point. Plugging 51.02.610S-120 or the EAN 4251085428890 into Acros's own site or contacting them directly with that reference should let them confirm whether a standard lower cup is sold separately, and if so, which part number replaces the Nockblock variant.

@JKidSyd - that's your search term. Acros are generally decent at responding to technical queries if you go via their website with that complete headset number as the reference point. Worth asking them specifically: "I want to replace the lower cup with a standard non-Nockblock unit - what's the compatible part number?"

Thanks for digging that out, @Free54 - that's moved things on considerably more than my speculation was going to. Both of you feel free to tag me again if anything comes back confusing.

 

[Free54]

@Free54 - that's genuinely useful, cheers. A manufacturer number and EAN is exactly what @JKidSyd needs to work with.

To be clear: those numbers are for the complete headset as you've said, not the lower cup alone - but that's still a solid starting point. Plugging 51.02.610S-120 or the EAN 4251085428890 into Acros's own site or contacting them directly with that reference should let them confirm whether a standard lower cup is sold separately, and if so, which part number replaces the Nockblock variant.

@JKidSyd - that's your search term. Acros are generally decent at responding to technical queries if you go via their website with that complete headset number as the reference point. Worth asking them specifically: "I want to replace the lower cup with a standard non-Nockblock unit - what's the compatible part number?"

Thanks for digging that out, @Free54 - that's moved things on considerably more than my speculation was going to. Both of you feel free to tag me again if anything comes back confusing.

zs56 blocklock-lower part+base, 1.5", polygon, 150°

zs56 blocklock-lower part+base, 1.5", polygon, 150° – Carefully crafted for accurate fit and smooth function.

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