will br

i had a tern bike just over a year ago. can't remember the exact model but it cost approx £500.while out on the bike i was over an hour into my ride when the folding mechanism failed and the bike collapsed.this happened without warning.fortunately i was not badly injured and i was able to get my money back.is this an isolated case or are there other similar instances?

Revoltingest

Dang!
What was the failure mode?

At least they gave you money instead of another bike....with a hinge.

fietsbob

they did a recall, mentioned here , as I recall, .. A lot of stress on a welded aluminum hinge plate to tube joint.. done quickly..

I was Told the Mk2 Brompton, tubes butt fillet brazed, to flat, forged hinge plates, steel, developed problems after years of hard use..

one passed through my hands it was OK.. , then I got a Mk4..










...

chainlink

If you search for tern frame failure in this forum, you’ll find quite a few entries and pictures. I wish I had known about it before I purchased my elink D7i. Can’t really sell it in good conscious even though nothing has happened. Yet. Glad nothing happened to you.

sweeks

Have you contacted Tern to see if your frame was recalled? The contact information has been on the web site for a long time: https://www.ternbicycles.com/us/product-alerts. If you bought the bike from a shop, they should have contacted you. If your frame was not involved in a recall, you can sell it with a clear conscience; you could also inform the prospective buyer of your efforts to determine the status of the frame.
Steve

downtube

You are not the first. I believe there are over 30 known failures ( users have listed similar problems from multiple forums ). Unfortunately I doubt you are the last.

Thanks,
Yan

dahoneezz

Is there something about the UK? It seems like this country is the Bermuda Triangle of Tern failures.

500 pounds looks like the Tern Link. The fact that he received full refund seems to me that the bike was bought new not second hand. So whether newly bought old old stock or new batch fresh from factory ... that be determined from the serial number.

The date of manufacture for the recall is 2012 (from Tern product alert posted).

Joe Remi

There's uhhh more than one...

chainlink

I purchased it in October and registered the bike. It’s an ebike and so far it rides great but after reading about so many frame failures it sometimes feels like the frame days could be numbered.

sweeks

Not all of these frames have failed; only a comparatively small number. I will agree that even one is too many, but there are a lot of risks in life and managing them is better (at least in my opinion) than living in fear. My original Tern frame did not break. I had 5,000 miles on it when it was recalled and I was reluctant to do it because it would be a big inconvenience. Of course a break would be a bigger inconvenience, but I was taking the precaution of inspecting the weld on a daily basis (yet another, smaller, inconvenience) and had not seen any evidence of a problem.

I realize that what I am saying here is controversial and I don't want to get into a big discussion. Based on the images of the broken frames that were posted on various sites it seemed to me that the welded joints were failing due to cyclic fatigue. The cracks started at the lowest point on the joint, just ahead of the hinge, and progressed upwards until the remaining weld was not able to bear the stress. At that point the frame would break. I proposed on the Tern Forum that in principle the weld failure could be detected at an early stage, and the break could be avoided. Obviously, no new bike should have to be inspected this way, but it seemed (to me) a reasonable way to have some peace of mind. I was roundly criticized by others, some of whom were calling for every single frame to be replaced. Eventually, there was a single frame whose owner detected a small crack in the exact place I predicted. I assume this frame was replaced before it broke. My own frame never displayed the early signs of the problem. All I had to do was run my finger along the lowest portion of the weld, feeling for any roughness that would represent the early stage of a fatigue fracture. I did this literally every time I got on the bike; it took 5 seconds. Eventually, I succumbed to the recall and got the new frame which has design changes that look to me as if they will effectively prevent the frame fracture. If your frame has these features (images attached), I'd ride the bike and not worry. If it doesn't, I would do the finger test once in a while, but if your frame is not in the recall group I would be less concerned.

You may consider my remarks for what they are worth; I hope they help. I'm quite happy with my Tern, and as disappointed as I was about the whole thing, I believe the company has done its best to remedy the problem and move forward.
Steve

Images: The first shows the gusset plate that reinforces the joint. You're looking into the forward half of the frame at a slightly downward angle. Just a bit of the plate is visible.
The second shows the weld along the midline of the bottom of the frame tube where the plate is located.

chainlink

Totally appreciate your input. Thank you for posting the photos too since that’s helpful. I’m also happy to hear you were happy with your Tern and put a lot of miles on it. That’s always good to hear!

MarcoPag

Thank you sweeks for posting those images, I just checked my Tern Link C7i bought in 2017 but probably built in 2015 or 2016 and it shows a similar gusset and a similar longitudinal welding on the underside of the front tube.
I have been upset after reading the reports of frame failures, but it seems they improved things after those facts.
So as a user of a current model I'm quite confident with the bike, and overall like it. I also check quite frequently the hinge... seems a good idea to me, with any folding bike. I'll try to attach a couple of crappy photos. Bye Marco

sweeks

Thanks, Marco,
You also have the "constant diameter" hinge pivot pin, which takes care of another potential problem that plagued the earlier design (though with less dire consequences).
How did you manage to post those images on your first post? Most folks here have to get to number 10 to earn that privilege!
Steve