bhkyte

I would be very suspisous about getting any Tern after the way IT HAS been covered up. The dealers can try to smooth it over with platitudes. i feel sorry for the deals. But the company HAS consealed this information reguards this issue on the internet.

I will not be getting a new or used tern now as they can not be trusted as a company. Most costomers will not have issues but why risk it.
As they say in dragons den.
I am out.

invisiblehand

But you want to control for exposure ... right? That is, Trek sells tons of bikes.

Presumably, consumers would like some notion of the frame's likelihood of failure. My guess is that it's quite small. But I think that brings us to BHKYTE's point that Tern's actions have only heightened the angst.

tcs

If you remember how Tern started, they said they wanted to 'turn' in a new direction for folding bike companies. It certainly wasn't with their product - Tern joined 47 other companies in building Dahon knock-offs. They weren't even very creative: The Dahon Jack became the Tern Joe; the Dahon Vigor became the Tern Verge.

What they promised instead was to 'turn' towards a new standard of customer support.

So then the first reports of frame breakage began to be reported on the Tern forum (back when it was an open board). Pattern: Consumer contacted company, Tern rushed to get the artifact (broken frame) away from the injured customer 'for study' and then...nothing. For months.

Without the promised sterling customer support, Tern merely becomes the purveyor of the most expensive Dahon knockoffs. I'm not feeling a viable business model in that approach.


(BTW - I disagree with some posters here as I did during the two different BikeFriday tikit frame recalls. IMO the maximum acceptable number or percentage of customers injured by the failure of a company's product is zero.)

bhkyte

There will always be some failures.
I come from a BMX racing background.
Everything breaks.
Ocassionally.
Its just a probability spectrum.
There is an acceptable failure rate.

jur

As enthusiastic I had been when seeing the Tern bikes at first, especially for the hinge and latch designs, so distrusting I am now after this whole saga. I can never recommend a Tern again. It isn't just a few 100 bikes. If you believe such a thing you need to check your gullibility score. Both Dahon and Tern ( and many other companies too, see the latest Thermomix saga) did damage control as much as possible to limit their loss. Make no mistake, this has a major effect on the bottom line and as soon as money is involved, you can forget about truth being first. Money is always first. So Tern wants you to believe that is only few 100 bikes, because that limits their loss. They claim it is a manufacturing fault. I think it more likely to be a basic design flaw. A welded joint must not be so iffy that even a small amount of lesser quality welding will virtually guarantee a break. Instead it should be over-designed for safety. They fell down on that very basic issue, and as a result, NO Tern bike should be regarded as safe.

bhkyte

Interesting jur.
To my eye the hingers and welding looked very secure on the new Terns. As an engineer, what do you think the design flaw may have been?

SkunkWerX

I'm curious as well regarding the thought of an engineering design flaw, if that is the case, then there are a LOT of those frames out there, with that particular hinge joint design, which would make this an industry wide concern. From the picture that I have seen, whether it be Terns, or others, it appears the welds broke, leaving the adjoining pieces intact?

Have there been any design changes since the defect was been determined?

Lastly, I am surprised we are not seeing any pictures, by owners, showing hairline cracks, something to indicate a complete failure might be forthcoming?

jur

I think the flaw is in the idea of a tube welded to a flat hinge face with very little structural shape to the hinge face that would hold the tube more securely while allowing the weld to be rather more than a thin line of metal put down. The hinge is in the middle of the bike right between the wheels, and that is the point of maximum stress. The rider's weight on the saddle in front of the rear wheel, exerts a strong downward force on the tube. Add some extra dynamic stress of riding on uneven road, and fatigue sets in quickly. A tiny flaw at the bottom such as a corner would be a stress riser where a crack would begin. With a very strong weld design which has lots of extra strength over and above the necessary amount to carry the rider, the crack would not form.

For sure a safer design is for the hinge to be a 3D piece that gets inserted into the tube after which a weld is put down. This tactic would allow the weld to be convoluted for extra strength. And it doesn't need to be like that everywhere, just the bottom where the maximum stress is. Heck even an extra reinforcing plate welded over the first weld at the bottom would be a massive improvement.

bhkyte

I see. So either terminate the tubes separately, then add a gusset or reinforcement welded section.

Is the problem the fact that the hinge is the connecting part of the frame? Ie the hinge plate IS the structural section joining the parts.
Rather than the two tubes meeting each with a hinge plate around it to aid conherencey. Downtube ,and brompton seem to do the later. More likely to come undone but not to stress crack at bottom?

None of my bikes have front folding sections anymore.

jur

Just to clarify on my previous post: With a flat face welded to a perpendicular tube, there is only a normal force on the weld.

Add a section where the weld tracks around a finger-shaped protrusion of a 3D hinge, to break the weld now also involves a shear stress, far stronger than a weld stressed with only a normal force.

bhkyte

OK got it thanks Jur.

ThorUSA

true but so is the downtube at the headtube .... more or less anyhow.... the first framebuilder just screwed up

bhkyte

Unfortunately more of this.
The frame failures are from more than one factory. So dont blame the first framebuilder as the only reason.

Also the recall talks about minor injuries.
Where as they has been servre injures to the head and face and a broken bone. Correct me if I am wrong.
The truth is out there.

Abu Mahendra

We can all understand, or see through, rather, attempts to downplay the problems in order to minimize financial loss. Insult (to the intelligence) added to injury.

Joe Remi

It is patently obvious that Tern does not know why the frames failed, and therefore are clueless as to how many more are at risk, or how to redesign the frames to solve it. Every bike with that name on it should be recalled for full refund because the owners shouldn't ride it or sell it. The damn things are worthless.

jur

One wonders if any engineering calculations were done on the weld joint strength, followed by actual testing to verify the design. My philosophy would be that the joint must have so much extra strength (derated, in engineer-speak) that flaws would not result in catastrophic failure. Any design that relies on near-perfect manufacturing techniques, while using factories that cannot give such high quality, will be doomed to fail. If you must have near-perfect manufacturing quality, then you need to control that too.

It would have been fairly straight-forward to design the weld stronger as per my example above, so that welding quality is less important.

I wonder of the latest Terns are any better. Did they learn from the mistake?

tcs

...the Morel/Gerard folding bike of 1895 or Faun and Dwyer folding bikes of 1896 or C.H. Clark's folding bikes of the 1920s or the Le Petit Bi of 1939 or the Puch Pic-Nic of the 1960s or the Raleigh Twenty Stowaway of 1971?

IMO the devil's in the details, execution is key and history shows us the basic concept isn't doomed to failure by any means - but if it's a particular concern for a given individual, there are always folding bikes without joints in their main frame tubes, like the Anemos, BigFish, Birdy, CarryMe, Ori, Mezzo, Strida...

tcs

I didn't realize things were so dire at the company. Tern's new model.

Christineenglan

I posted about my experience of my X10 frame shearing in two in 2014, and eventually my dealer offered me my money back and a £200 voucher. I was totally disgusted with this approach but due to ongoing injuries to my wrists and unrelated issues I have not yet settled the matter.
I thought that readers might be interested in my experiences as I suspect that I am very different to most of you. I am a lady aged in my 50's weighing 140 pounds and 5'9"tall. I am an experienced cyclist although I am am now slow, careful and not very strong. I used it to cycle along quiet roads and cycle paths for pleasure.
My husband bought me an X10 as I needed a folding bike and this one was lightweight and a beautiful orange colour.
We bought it directly from a dealer although we got it at a discount as it was used as a sample bike in the store. I took it in for a six week service in July 2013 and I understood that the next service was due one year later.
In May 2014 I had just freewheeled down a steep hill and stopped at the bottom for a moment. Setting off again the bike came apart at the hinge and I fell onto the ground. As I was not going fast I only suffered minor injuries.
I was shocked and realised that I had it happened a hundred yards earlier than I could have been killed.
Once I had calmed down I called Tern as I was so shocked and assumed that it was the first time that this had happened to anyone.
To cut a long story short no one at Tern or Evans, the dealer was concerned.
After long conversations with them both I returned the bike to Evans and this is what they wrote to me:-

As previously indicated and after provisional inspection by our head of Warranty, when returned to us your bike was found to have a very poorly adjusted main hinge; having spoken to my colleague and Mark Bickerton at Tern, this issue is a known factor in causing frame failures and is not related to the quality of manufacture or initial assembly.

Folding bikes in particular have a relatively high maintenance requirement and the main hinge in question is designed to be adjusted during routine maintenance, in order to ensure that the correct closure tension is achieved.

In this regard, our records indicate that you have not had the bike serviced by Evans Cycles since 11/12th July 2013 and, assuming a reasonable amount of usage in the intervening time, this would not be deemed to be an adequate service level, unless of course the work has been carried-out by a third party.

It is the case that riding a Tern such as yours with a loose main hinge, as was found on your bike, will place excess strain on the adjoining welds and can onwardly cause them to fail catastrophically; in the view of my colleagues this is the cause of your frame failure, rather than any manufacturing defect or assembly error.

For clarity, although there was a product safety recall in relation to early batches of these frames, the frame on your bike was not one of those affected and Tern are not aware of any strength or safety concerns with the batch of frames to which yours belongs and our view at this point is that it entirely complies with the relevant UK and European safety standards.

Given this our view is that the issue, highly unfortunate as it undoubtedly is, was not caused by a poorly manufactured or assembled product and therefore Evans Cycles would not accept liability in any way for the situation....

They looked at two separate pieces of bike and decided that the hinge was incorrectly tensioned. I know for certain that it was not as I folded it away after every use and then opened it out and clipped the hinge together.
Before I sent it to them I tried to put it back together for photographs and as it was broken it just fell apart so there is no way what they are saying is true.
Apparently the alleged loose hinge caused the weld to snap.
Does anyone have any comments?
By the way I insisted that they return the bike which is now sitting in a storeroom at my solicitors office.

bhkyte

I have a comment.
Complete sham.
Shame on Tern and Evans.

I would treaten legal action as this is simply untrue. Will they get an engineer to look at it.
Independently.
What do the legals and engineers here feel about this?

jur

I don't have any personal experience with any Terns. Your story is quite familiar with regard to Tern's willingness to accept responsibility for their frames poor safety record. Tern was formed by Josh Hon after a family rift drove him away from his father's company Dahon. Terns are close copies of Dahons with one big exception: As far as we know, Dahons have enjoyed a great frame reliability in general, as opposed to Terns, which have now had numerous cases of frame failure, all in exactly the same way. Tern has done damage control by claiming there was a manufacturing fault in a batch, and recalled that batch. Later, as more and more frames broke, they were forced to expand the recall.

In my opinion, the weld joint was poorly designed, as evidenced by the failures that span accross batches, accross models and even accross factories. Tern wants you to believe that it is either a batch problem or outrageously in your case, a customer error.

Don't accept those lies. Stand your ground. See if your lawyer would consider a class action. There is plenty of starting material in this forum under several topics, just do a search.

Tern needs to eat their frame guarantee. They need to be held accountable for a poor weld design. Their handling of this fiasco earned them only to go bankrupt.

jur

Just an added comment on Evans and Mark Bickerton's statements: Even accepting a case of a poorly adjusted hinge clamp (not saying that yours was such a case), the hinge weld should not self-destruct when poorly adjusted. It is a safety critical part and MUST be able to handle such issues. The bike might perform poorly such as wobbling while pedaling but should never self-destruct. Don't accept that BS.

Christineenglan

I forgot to mention a few things -
My bike was not from either of the recall batches.
I don't understand why Tern have not expressed any interest in examining it in case they need to look at other bikes from the same batch.
I did try to take legal action and that is why Evans did the report and then only offered a refund and £200. I guess it will start to cost me a lot of money if I continue.
I understand that as I live in England then my complaint is with Evans as they were the retailer and not Tern. I think that the situation is different in America and over there Tern is responsible for the quality of their products and can be sued directly in a class action if they are found to be faulty.
My reason for writing today is to possibly help others who have been affected and even injured. I am also very concerned that someone could be killed so I want to do whatever I can to avoid that.
Finally, I still have the bike if anyone is interested as I note from previous commentors that they have handed their broken bikes over to Tern and not got them back.

linberl

See if you can use social media and get some press attention. It is cheaper than lawyers and can be as effective. Consider a change.org petition, creating a facebook page highlighting the problem, getting people to tweet with a hashtag (#ternbikedanger).
Become enough of a pain, and they might do the right thing.

tds101 

Do not let anyone get the bike back! It's time to make Tern stop selling deadly products,...

I agree. Post to Twitter, Facebook etc, pictures of the defective bike. Make sure as many people as possible see what happened. Make it so other people know what Tern is trying to cover up.