Knock-Block failed - Trek Rail 9.8 carbon frame damage

Jamescoughlan

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Jul 13, 2020
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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 with but I would claim this "feature" is a design failure and the consequential damage has basically/potentially written my frame off.

The bike shop is offering me a replacement frame at cost or I look to repair the damage: thoughts and feedback welcome! Extremely upset if I'm honest; £6k bike, 200 miles in and looking at a massive bill for a basic wash-out. Not cool.

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Frankenbetty

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Jun 6, 2020
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32
Llandegla
Id put a sticker over it. Frames are hugely overbuilt at the head tube/down tube bit anyway to cope with all forces involved so it wouldn't bother me too much.
But if you don’t want to do that a Carbon repair company would do it a lot cheaper than a new frame even at cost price
id be pissed with Trek though that’s a shitty response considering it shouldn’t have happened in the first place
 

Jamescoughlan

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Jul 13, 2020
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I'm inclined to agree. I've got in touch with a carbon repair facility and will see what they say. I don't think the structural integrity of the frame is compromised but worth a check!
I think it's a poor response, particularly when you consider the cost. I notice that the 2021 Slash has the option not to run the knock-block system which speaks volumes!
 

Mteam

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Aug 3, 2020
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You'd think they might offer you a new front triangle under some sort of crash replacement scheme, ie at a heavily discounted price?

As it stands, I guess you can get to the inside of the frame at that point, so can see if it's showing any damage on the inside?

I'd probably touch it up with epoxy, sand it back smooth, repaint if I could be bothered and carry on riding it.
 

Jamescoughlan

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Jul 13, 2020
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They won't offer a front triangle only, just a complete frameset including rear triangle.

The cost price of the replacement frameset was definitely "fair" as a % of the original sales price but still astronomical considering the original outlay of over £6k.

I do think pretty poor service from Trek.
 

Dano78

Member
Dec 3, 2019
161
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Uk
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 with but I would claim this "feature" is a design failure and the consequential damage has basically/potentially written my frame off.

The bike shop is offering me a replacement frame at cost or I look to repair the damage: thoughts and feedback welcome! Extremely upset if I'm honest; £6k bike, 200 miles in and looking at a massive bill for a basic wash-out. Not cool.

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I keep seeing eyes and a face , sorry for your dilemma trek are out of order for that
 

Doug Stampfer

Well-known member
Jul 7, 2018
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Yeah they cover themselves pretty well don't they designing something supposedly to stop damage happening during an 'accident' then being able to conveniently absolve themselves of responsibility beause it is accident damage.
When you actually think about it, it is negligent of them to design a feature to minimise damage to the frame that actually is the weak point.
I've no brand loyalty to any one but I don't think I'd buy another Trek.
It must be a medium size frame?
 

Doomanic

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I would be suggesting to Trek that perhaps the Knock Block isn't fit for purpose. Did you pay on a Credit Card? Even if you only paid a deposit you can still get them involved. How is the bike insured? If it's on your home insurance you may have accidental damage cover.

The bike does look sad though...

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Philly G

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Jun 29, 2020
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They won't offer a front triangle only, just a complete frameset including rear triangle.

The cost price of the replacement frameset was definitely "fair" as a % of the original sales price but still astronomical considering the original outlay of over £6k.

I do think pretty poor service from Trek.
I would have thought this would definitely be a warranty issue, since the knock block is supposed to prevent this very thing? Especially when your crash was just a wash out
 

BrentD

Well-known member
Jun 25, 2020
168
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New Zealand
I would have thought this would definitely be a warranty issue, since the knock block is supposed to prevent this very thing? Especially when your crash was just a wash out
Gotta agree with Philly on this one and I'm not sure I'd be comfortable still riding that given there appears to be broken fibres there. Sucks to be the original poster.
 

Philly G

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Jun 29, 2020
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Am I right in think gate trek has a restrictor in the headset as well as the pads on the down tube?
Yes. There are tabs that lock into machined recesses on the stem and the spacers. These tabs must have snapped off in the OP's crash. Those rubber bumps aren't stuck on very well either.
 

R120

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Apr 13, 2018
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Surely thats a pretty clear component failure then, if they design a frame reliant on a knock block to prevent damage to said frame, and it fails that seems pretty clear cut
 

Dano78

Member
Dec 3, 2019
161
34
Uk
Yeah they cover themselves pretty well don't they designing something supposedly to stop damage happening during an 'accident' then being able to conveniently absolve themselves of responsibility beause it is accident damage.
When you actually think about it, it is negligent of them to design a feature to minimise damage to the frame that actually is the weak point.
I've no brand loyalty to any one but I don't think I'd buy another Trek.
It must be a medium size frame?
Maybe threaten them with legal action see what they say as your completely in the right , trek aren't exactly cheap you may as well buy from a on line company if there not going to back there product up
 

KeithR

Well-known member
Jul 1, 2020
679
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Blyth, Northumberland
Yeah they cover themselves pretty well don't they designing something supposedly to stop damage happening during an 'accident' then being able to conveniently absolve themselves of responsibility because it is accident damage.
Unless Trek actually market Knock Block as a component which will prevent such damage - and I've been unable to find anything saying that - it's not surprising that they characterise this as simple crash damage in warranty terms.
 
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KeithR

Well-known member
Jul 1, 2020
679
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Blyth, Northumberland
Gotta agree with Philly on this one and I'm not sure I'd be comfortable still riding that given there appears to be broken fibres there.
Agree 100% with this - there's possibly damage at a structural level which is not visible to the eye.

Trek spell this out:
Carbon fibre is not indestructible
But like anything, carbon fibre is not indestructible, and not all damage to carbon fibre will be visible. Compare a carbon fibre part to a metal part. When you damage a metal part, it will bend or deform. When you damage a carbon fibre part, it could break or it could conceal damage from the naked eye.

In other words, just because a carbon part looks normal after an impact or accident does not mean that it is safe to ride.
 

Philly G

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Jun 29, 2020
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Legal action for what? They're complying completely with the terms of their warranty, which the OP accepted when he bought the bike.
Whether or not Trek explicitly state the knock block will prevent damage, the frame, with it's straight down tube, is designed in such a way that the fork crown can hit the frame and damage it. So Trek designed the knock block to prevent such damage . The knock block has failed in its intended purpose, so I would argue Trek have a case to answer.
 

KeithR

Well-known member
Jul 1, 2020
679
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Blyth, Northumberland
the frame, with its straight down tube, is designed in such a way that the fork crown can hit the frame and damage it.
True. But then we have to ask (Trek's lawyers would): how many Trek bikes are damaged this way?

I've just done a search - using several search terms (my Google-fu is pretty strong) - and I'm finding nothing to suggest that this is a regular occurrence.

Which is all the defence Trek needs.

So my question stands: what would the legal action be about? Trek is by all accounts getting this right for the most part, and that's all they need to do.

It stinks - I'm pro the OP, not Trek - but I doubt there's a case against Trek here, even if their frame designs make damage more likely.
 

Sophie777

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Jul 3, 2018
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Canada
They won't offer a front triangle only, just a complete frameset including rear triangle.

The cost price of the replacement frameset was definitely "fair" as a % of the original sales price but still astronomical considering the original outlay of over £6k.

I do think pretty poor service from Trek.

Have you had the bike for 90 days or less? Because if this is the case, and you purchased the bike using a credit card, your credit card company may cover the cost of the damages.
So I would call your credit card company.
 

Philly G

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True. But then we have to ask (Trek's lawyers would): how many Trek bikes are damaged this way?
The damage can only occur if the knock block fails, which in the OP's case it has. Just because knock block failure may not be common ( I don't actually know ) doesn't mean Trek shouldn't cover the owner when it does. My Bike Yoke dropper failed not long after purchase - not common apparently - but is there grounds for Bike Yoke not to warranty just because the fault isn't common ? No, they warrantied it for me, as they should. Not trying to be argumentative, just don't really follow your logic ;)
 

Jamescoughlan

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Jul 13, 2020
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Cheers all for taking the time to reply to this; I’ll try and answer some questions:

Size medium
I bought through C2W, not credit card, back in July
Seriously unhappy with Trek’s position but I won’t be entertaining any legal action for many reasons including time, emotional resource etc.
I see the sad face on the frame... just imagine what mine looks like!
I too couldn’t find any internet examples of knock block failure either, however the Trek rep said, in writing, that he’d seen a failure on the trail! The wally.
I’ll look into accidental damage claim on my house insurance.
I’ve had a quote for £320 including painting to repair.

Still love the bike though. I’m having a Fox DPX2 Rear shock custom tuned and the stroke corrected - the reactiv shock is total bobbins - and a Smashpot on order so I’m already invested quite heavily!

Doubt I’d buy another Trek again given this treatment which is a shame because VFM and performance are very good.
 

Darren

Active member
Sep 25, 2019
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Warwick
Who inspected the failed knock block components? What is to suggest there is not material or manufacturing defect in the failed components?
I wouldn't be letting this go without answers to the above questions. Perhaps Twitter is the best place to seek answers.
Trek describe their warranty as industry leading - how does that statement align with their response here?
 

SquireRides

E*POWAH Elite World Champion
Sep 4, 2018
540
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UK
I think the problem is you crashed your bike.

I'm not sure what a 'simple washout' is but whether it was slow, not from a great height or whatever, sometimes it can still put a lot of force in to just the wrong place...

Unfortunately the knock block is just another component, not an insurance policy.
 

Jamescoughlan

Active member
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Jul 13, 2020
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I've attached a couple of photos of the broken knock block frame pin and top cap. You'll see that the "pin" has sheared and there is a slight stress mark in the top cap where they made contact.

Incidentally there was no other bike damage so make of that what you will.

I don't believe there is any warranty claim here, I've never made that claim, but i do believe that the fallout from such a "feature" should not be damage to a frame. Again, I raise the point that knock block 2 can be safely removed on the Slash.

I'd love to go one twitter but I don't have an account and have no wish to open one unfortunately and to my, potential, loss.

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SquireRides

E*POWAH Elite World Champion
Sep 4, 2018
540
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UK
Is that pin (the Stop Chip) made from steel or aluminum?

Trek's marketing says "hey Knock Block removes the whole problem of forks hitting the frame...
... but we include rubber bumpers 'just in case'. It's worry free!"

But the diagram shows a 'replaceable' stop chip:

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Which makes me wonder if it is designed to fail under certain loads???? Why would they call this one part of the system replaceable?

I can't think of a reason you would want it to fail though...
 

Jamescoughlan

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Jul 13, 2020
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The stop chip is an aluminium alloy.

It's a bit of an oxymoronic feature really which Trek clearly have no intention of backing up.

You'll see in one of the first pictures that the charger damper adjuster tore through the rubber bumper too. I only removed that to enable full inspection of the damage.

They must have done a shear test on the stop chip, I wonder what the calculated failure force was? I've got an idea... something equivalent to one 42 year old at a weight of 80kg (of middle age muscle spread) and a carbon Rail...
 

SquireRides

E*POWAH Elite World Champion
Sep 4, 2018
540
556
UK
The stop chip is an aluminium alloy.

Confusing. I mean, you don't make something small and aluminum if you want it to be subject to highly leveraged forces, which if you think about a typical 42 y.o. putting all their weight through the end of 780 mm bars during a stack at any speed over 10mph will be.... I'm not a mathematician... but it would be a lot.
 

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