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-   -   Tern Link snapped in two. (https://www.bikeforums.net/folding-bikes/1314201-tern-link-snapped-two.html)

Duragrouch 08-28-25 11:18 PM


Originally Posted by Barchettaman (Post 23595766)
https://cimg8.ibsrv.net/gimg/bikefor...e2e0316b3.jpeg

apologies for the poor photo, I wanted to get rolling.

This is its slightly dusty replacement. A bit bigger than the dead one and in need of new cables and housing but it’ll do for now. Rides nicely on the 406/47 tyres.

While seemingly the same, that frame may be slightly different. I think I see a thickness-doubler weld gusset on the bottom of the main tube on the forward side of the hinge. That doesn't help your failure mode, but I think is an indicator of later, post-recall frames. The aft weld geometry may be unchanged but improved in quality, I don't know. Will be good to know where each frame sits in the recall chronology.

The hinge is pivot is also changed, if you compare the two.

If not already in the old bike, hopefully the new bike has stronger weld filler material and the whole frame post-weld heat-treated to bring back up to T-6 temper strength, if it's 6061-T6 and not 7005, the latter of which was designed specificially for bikes to not require heat treat after welding.

At least now you have disc brakes.

Jipe 08-29-25 01:04 AM


Originally Posted by Ron Damon (Post 23596011)
A famously failure prone Al-alloy Tern broke on your 105kg frame, and the replacement is another Al-alloy Tern for your 105kg frame? Are you familiar with the Darwin Awards?

The issue with the previous old broken frame is not due to the hinge itself but to the welds.

Its more a manufacturing problem than a design problem that was solved on more recent Tern frames.

BTW., even if it would help to avoid broken frames like this one, the Deltec cable is meant to reduce the constraints on the hinge and increase the hinge life, not to solve bad welding/bad manufacturing.

The safest is to find out the manufacturing date of the broken frame and of the replacement frame and see if there is a Tern recall for any of those two frames.

Barchettaman 08-29-25 01:16 AM

It’s a later frame - about 3 years old and hardly used - and the welds/gusset area is different. Hopefully I won’t Darwin myself.

Cheers all.

Duragrouch 08-29-25 02:11 AM


Originally Posted by Barchettaman (Post 23596069)
It’s a later frame - about 3 years old and hardly used - and the welds/gusset area is different. Hopefully I won’t Darwin myself.

Cheers all.

Sounds good. Most folders don't get used much, so bargains on the used market (except Brompton); unlike mine which has been my 100% use for 10 years now, after low use for 9 years (but on second frame).

Barchettaman 08-29-25 02:22 AM


Originally Posted by Duragrouch (Post 23596054)
While seemingly the same, that frame may be slightly different.

At least now you have disc brakes.

The mechanical disc brakes are bloody awful but I will sort them out with better cables and housing when I get back to Frankfurt. The V brakes on its dead predecessor were perfect.

Duragrouch 08-29-25 02:32 AM


Originally Posted by Barchettaman (Post 23596074)
The mechanical disc brakes are bloody awful but I will sort them out with better cables and housing when I get back to Frankfurt. The V brakes on its dead predecessor were perfect.

Yeah the mechanical calipers on Dahons with disc brakes were awful too; Piston only extends on one side, and the mechanical cam and ball mechanism has no seals to keep from dirt contamination, which happens almost instantly when riding in rain. Problem is, Dahon "innovated" by offsetting the discs 15mm inboard, ostensibly to reduce incidence of damage, but that means, that to replace the calipers with good ones, you need to replace the hubs, for standard disc spacing.

Fentuz 08-29-25 02:49 AM


Originally Posted by Barchettaman (Post 23596074)
The mechanical disc brakes are bloody awful but I will sort them out with better cables and housing when I get back to Frankfurt. The V brakes on its dead predecessor were perfect.

you might want some compression-less housing and if you can be bothered, some TRP spyre calipers. The "budget" mechanical caliper fitted on these tern by default are useless...

Fentuz 08-29-25 02:52 AM


Originally Posted by Duragrouch (Post 23596077)
Problem is, Dahon "innovated" by offsetting the discs 15mm inboard, ostensibly to reduce incidence of damage, but that means, that to replace the calipers with good ones, you need to replace the hubs, for standard disc spacing.

I did not know that; I would assume they used std flat or post mount and fit them to a custom adaptor/bracket (offset 140/160 plate)

the tern picture shows what looks like a std post mound on 100mm hub
https://www.ternbicycles.com/sites/d...?itok=36wl1Vyd

Duragrouch 08-29-25 03:03 AM


Originally Posted by Fentuz (Post 23596079)
I did not know that; I would assume they used std flat or post mount and fit them to a custom adaptor/bracket (offset 140/160 plate)

the tern picture shows what looks like a std post mound on 100mm hub
https://www.ternbicycles.com/sites/d...?itok=36wl1Vyd

I don't know, I haven't yet futzed with those. But someone on here bought a Dahon Launch with the 15mm offset and did a post on here, basically "WTF?!" and asked if there were easy solutions, there weren't evidently, because he had his bike-monger swap out the hubs on the wheelset. I had read about the 15mm offset previously on Dahon's website, but having never had a disc bike before, so did not even consider a caliper compatibility issue. Also, the disc a lot closer to the spokes, may not have allowed clearance for other calipers to fit, especially calipers that actively pushed on both sides of the disc. That member's post to ask how to swap calipers was due to terrible performance of the mechanical calipers and pulled one apart and posted photos, and the problems were obvious, a simple mechanism with no seals against contamination, plus piston only extends on one side. IIRC, that member was in an area with almost no rain, but a whole LOT of sand, as far as the eye can see, contamination issues even riding purely on paved road.

Fentuz 08-29-25 03:24 AM


Originally Posted by Duragrouch (Post 23596081)
That member's post to ask how to swap calipers was due to terrible performance of the mechanical calipers and pulled one apart and posted photos, and the problems were obvious, a simple mechanism with no seals against contamination, plus piston only extends on one side. IIRC, that member was in an area with almost no rain, but a whole LOT of sand, as far as the eye can see, contamination issues even riding purely on paved road.

I remember the post with poor quality dahon caliper (housing casting full of flashes and the poorly machined ball bearing locations). Hence, my suggestion to OP to fit some spyre if 100€ cost is acceptable to him. The spyres are reliable and have descent braking power. They are the "go to" for unsupported remote applications and do work well in CX racing

Duragrouch 08-29-25 03:29 AM


Originally Posted by Fentuz (Post 23596082)
I remember the post with poor quality dahon caliper (housing casting full of flashes and the poorly machined ball bearing locations). Hence, my suggestion to OP to fit some spyre if 100€ cost is acceptable to him. The spyres are reliable and have descent braking power. They are the "go to" for unsupported remote applications and do work well in CX racing

I've generally heard good things about those. I'd be curious about the mechanism; If they have dual pistons (the mech calipers I see at my LBS do, they might even be spyres), how it operates (cam or helix/screw), and how well that is sealed.

And as long as it doesn't have the 15mm inboard offset (I don't think applies to anyone except some Dahon models), a swap to anything else should be easy.

I'd be interested in hydraulic, heard great things, but that's an area where I would only go with a known and quality brand, as cheap brand hydraulic stuff leaks and is not durable, as a rule. I've read great things on here about Shimano (Deore?) hydraulic calipers.

Fentuz 08-29-25 04:00 AM


Originally Posted by Duragrouch (Post 23596083)
I've generally heard good things about those. I'd be curious about the mechanism; If they have dual pistons (the mech calipers I see at my LBS do, they might even be spyres), how it operates (cam or helix/screw), and how well that is sealed.

And as long as it doesn't have the 15mm inboard offset (I don't think applies to anyone except some Dahon models), a swap to anything else should be easy.

I'd be interested in hydraulic, heard great things, but that's an area where I would only go with a known and quality brand, as cheap brand hydraulic stuff leaks and is not durable, as a rule. I've read great things on here about Shimano (Deore?) hydraulic calipers.

I think it is the same basic concept; as the lever is pulled, it rotates a plate with location track for bearing. The track has a variable depth leading to a piston transltion movement. however, on the spyre, it is twin pot rather than a single side and they have seals and bearing rather than bushes to smooth the mechanism

My daughter runs trp HY/RD caliper and they work well. only issue is the big hydrau reservoir makes the caliper adjustment a bit fiddly because the hex driver does not fit well (need a cut down one)

My son runs clark clout junior which is a copy of the cheaper shimano hydrau and it works well; you can see it was re-engineered and manufactured to be inexpensive but they are fine if you are not after the lightest strongest setup with all bells and whistles.
Actually these clark clout could be another good option for OP. ~50€ per kit so 100€ total and you can offset cable housing cost

I run sram rival and they work well; I boiled them once but I was using them on a steep offroad downhill (solution was to go for 180 rotor on front)
I now run hope RX4+ 4 pots calipers which are very strong and sometime "overbraked" but I prefer to be able to lock the wheel and adjust braking technique to tyre grip rather than running out of brake (motorsport old habit).






Duragrouch 08-29-25 04:32 AM

^^ Absolutely. I always have preferred to have a car/aircraft/sailboat/bike with more capability than me. I want brakes capable of standing the bike on its nose and put wrinkles in the asphalt. I need better brakes on my folder, but have waited in order to hopefully get a disc bike.

Barchettaman 08-29-25 05:22 AM

Thanks all for the options.

My first port of call will be a cable and housing upgrade. I have Jagwire cables and housing on the broken bike so will swap those in, assuming the front is long enough.

I wondered if an upgrade to hydro would be a future option but I will see what the braking is like once they’ve had a little love.

at the moment the levers are super stifff and modulation isn’t great, but they do stop the bike. It’s just unpleasant.

Duragrouch 08-29-25 05:38 AM


Originally Posted by Barchettaman (Post 23596109)
Thanks all for the options.

My first port of call will be a cable and housing upgrade. I have Jagwire cables and housing on the broken bike so will swap those in, assuming the front is long enough.

I wondered if an upgrade to hydro would be a future option but I will see what the braking is like once they’ve had a little love.

at the moment the levers are super stifff and modulation isn’t great, but they do stop the bike. It’s just unpleasant.

Before swapping the cables, loosen the cables on the new bike and check that the levers themselves move freely, otherwise you'll want to swap the levers as well. Sometimes the lever return spring (pioneered on Shimano SLR(?), reduces cable friction) is broken. I personally don't like riveted pivots on levers, I prefer a bolt with nylock stopnut, so I can torque to where it just binds, then back off just a tad, so moves freely but without a lot of lateral play. Plus, able to service return spring and bushing.

Barchettaman 08-29-25 08:17 AM

Great advice. Thanks; I will be sure to check that too.

tomtomtom123 08-29-25 08:43 AM


Originally Posted by Barchettaman (Post 23596109)
Thanks all for the options.

My first port of call will be a cable and housing upgrade. I have Jagwire cables and housing on the broken bike so will swap those in, assuming the front is long enough.

I wondered if an upgrade to hydro would be a future option but I will see what the braking is like once they’ve had a little love.

at the moment the levers are super stifff and modulation isn’t great, but they do stop the bike. It’s just unpleasant.

Bike-discount has Shimano mt200 to mt420 hydraulic calipers prefilled with levers for a set pair both front and back for between 20-50 euro. But you have to check the cable length because each listing has different lengths. I think for Dahon/tern you would need at least 1900mm rear, but 2000mm better. Front is probably 800-900mm.

tds101 08-30-25 10:01 PM


Originally Posted by Ron Damon (Post 23596011)
Are you familiar with the Darwin Awards?

Surely your family must be, considering how all you spew is disgusting venom. What a waste of oxygen you truly are. :wtf:

Barchettaman 08-31-25 11:12 AM


Originally Posted by tds101 (Post 23597267)
Surely your family must be, considering how all you spew is disgusting venom. What a waste of oxygen you truly are. :wtf:

The question was directed at me; I didn’t take offence. It was perhaps clumsily worded but the sentiment was fair.

I have bought a similar if much later model and yeah, I guess I am taking a risk. I am a bigger rider, and will be careful to regularly inspect the area round the hinge on this bike.

I am hoping that the bigger tyres will reduce vibration/shocks on the frame and stress on that weld area.

Cheers all. Let’s remain friendly, civil and courteous to each other on this excellent forum.

tds101 08-31-25 07:48 PM


Originally Posted by Barchettaman (Post 23597571)
The question was directed at me; I didn’t take offence. It was perhaps clumsily worded but the sentiment was fair.

I have bought a similar if much later model and yeah, I guess I am taking a risk. I am a bigger rider, and will be careful to regularly inspect the area round the hinge on this bike.

I am hoping that the bigger tyres will reduce vibration/shocks on the frame and stress on that weld area.

Cheers all. Let’s remain friendly, civil and courteous to each other on this excellent forum.

I do understand that it WAS directed at you, but it was with disdain, and hatred, that it was said. You're trying to have a discussion, respectfully, and I'm sorry I'm interrupting that. This individual is also attempting to belittle you, and has a history of constantly berating, belittling, and accusing all of the members of this forum of being all the things he accuses others of being. Personally. I was enjoying this discussion, and another, until "it" returned to start the hatred anew. I'll respect you, and the other members here. This racist, xenophobic, nationalistic individual? Not a chance. His unwarranted insults are disgusting, and totally unacceptable. He was most certainly being contemptuous toward YOU, and others in this forum,

Ron Damon 08-31-25 10:31 PM

Yeah...okay...

tds101 09-01-25 03:44 AM


Originally Posted by Ron Damon (Post 23598054)
Yeah...okay...

:banned:

MalcolmH 09-01-25 07:35 PM

Hi. The only references i could find to Tern Link D8 frame recall was to 2011 - 2014 frames where the frame number starts with AI. Wondering if the snapped frame here was such a frame or if the problem is wider? Our frames numbers start with BC and am feeling nervous ...

Fentuz 09-02-25 01:14 AM


Originally Posted by MalcolmH (Post 23598697)
Hi. The only references i could find to Tern Link D8 frame recall was to 2011 - 2014 frames where the frame number starts with AI. Wondering if the snapped frame here was such a frame or if the problem is wider? Our frames numbers start with BC and am feeling nervous ...

it all happened after the split of Tern from Dahon (and family divorce). The first few years of production in the chinese factory (initially a subcontractor of the Taiwanese Dahon factory, if memory serves) had some welding expertise issues and the after-sales/warranty service was not good hence the poor initial reputation. However, things settled and later models are deemed fine.

The recall appears to affect frame manufacturer up to 2012 https://www.ternbicycles.com/en/fram...ement-notice-0
However, from bicycle magazines, it appears these frames equiped bike sold until 2014.

Smaug1 09-02-25 01:58 PM


Originally Posted by Ron Damon (Post 23596010)
A famously failure prone Al-alloy Tern broke on your 105kg frame, and the replacement is a famously failure prone Al-alloy Tern for you 105kg frame? Are you familiar with the Darwin Awards?

I'm sure he checked the database john m flores mentioned before buying, as he won't want to execute another unplanned dismount. ;)


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