Tern Link conversion with Tongsheng Tsdz2 kit. Question...

[Mark Waters]

Hi, I'm looking to extend the power cable from the battery to the motor on my TSDZ2 kit, its about 20cm too short.

I need 2x male to female 3.5mm Bullet head connector terminals.

Reason is, I bought a kit for a CX bike, with the battery mounted on the downtube which was great but thought it would make a cleaner conversion on Tern Link D8. Now, the battery is rear rack mounted but the power cables from the battery to the motor are too short.

I could get them made up, but just wondered If there's any pre wired connectors out there. Cheers Mark

 

[Woosh]

did you get the kit from me? If you did, then we supply free extension leads, just email support. You also need a bit of spiral wrap to protect the lead.

 

[Mark Waters]

Hi, I did, OK, will do. Cheers

Mark

 

[Bogmonster666]

Hi, I can see you have the frame with the modified extra support just in front the frame hinge. Many of these bikes had a recall and the frame was swapped due to the frame shearing just after the hinge. As I understand it, the failures tend to be without warning.

I think there were still some cases of failure on the re-designed frame. I know all this as I have a very similar Tern bike (which has been fine).

The motor may well put some additional stress on the frame due the extra torque being delivered? Tbh, I tend to think a mid drive motor isn't really going to add a lot of additional stress to the hinge area, and that failure is more likely with heavy riders and uneven surfaces and pot holes.

I definitely would not put a front hub motor on one of these bikes.

I'm not an engineering and certainly not trying to tell you what you should or should not do, just highlighting a potential problem that could result in a very nasty accident.

I did consider converting my Tern folder but have held off. If I do decide on a folder conversion I think I will get a steel framed Dahon donor?

Here is one of the numerous threads discussing it:

Anyone riding a Tern Eclipse X20? - Bike Forums

Folding Bikes - Anyone riding a Tern Eclipse X20? - Hello For a new folder, I'm looking at Tern and would like some feedback from anyone who rides the Eclipse X20 . Once folded, it's not much bigger (42 x 89 x 76cm) than a Verge (38 x 79 x 72; P20 or X10 ), so I was wondering if its 24" wheels...

www.bikeforums.net

And you can see there the black bike in that thread appears to be the modified frame design with the extra gusset.

I don't think Dahon's are immune to failing here either, but far fewer cases that I have seen. I imagine a steel frame would be less prone to this kind of failure?

 

[Mark Waters]

Hi Bogmonster666

Thanks for the post. Yeah, that's quite concerning and the pictures! Wow.

I've checked the original recall for the 2011-12 and 2014 issues and the frame number (a pain taking the kit off again) and mine's not in the recall batches.

Plus, yes, I agree a front hub would be putting too much strain on the hinge, the mid drive a safer option hopefully, it's very well secured as well, with a couple of additional Jubilee clips and the nuts all have threadlock on them (due to the absence of the clamp underneath.

We'll, have to wait and see....!!

Cheers

Mark

 

[guerney]

Food for thought: Before I applied a drop of oil to silence a creak coming from inside the hinge mechanism of my similar shaped 20" wheeled aluminium framed Dahon Helios P8 Bafang BBS01B conversion, it was obvious when the frame flexed at the onset of high sustained torque from the motor. It hasn't snapped in half yet, or folded permanently. BTW how did you secure your battery to the rack? I drilled through a bit of rot-proof pallet wood. It'll be replaced by aluminium as originally intended, which I now have and will get around to.

 

[Bogmonster666]

On the subject of things shearing, the tsdz2 case has been known to shear as well. As far as I know it happens on motors that are not mounted at all points. In particular, I think missing off the bracket on the left hand side is an issue (and I can see on your bike the bracket is in place so good on that front). I would be interested to see where the jubilee clips are, ideally you want to try and avoid the motor rotating into the frame at the front (I know some folks use padding to try and distribute the pressure on the motor case but no idea if that really helps). If you have managed to somehow anchor the motor from the rear anchor point with jubilee clips and bailer twine then that my work.

 

[guerney]

My bike's frame has a supporting strut over the hinge.

 

[Bogmonster666]

Another though is chainring size. Not sure how many teeth are on the original chainring, but the tsdz2 only has 42t default and woosh warranties up to 44t. The tsdz2 on stock firmware stops assisting at ~75 rpm and starts tailing off before then. Assuming 11t at the back and 42t at the front, you should get assistance up to about 15mph I think, but will need to pedal like the clappers to get up to 20mph. You will have no problems with hills though!

Whether any of that is a problem for you depends on how you use the bike, for urban commuting and pottering around then it should be fine.

 

[Bogmonster666]

@guerney, that picture reminds of Blackpool eliminations as a kid

 

[Mark Waters]

Hi

I've anchored to the front supporting strut, using a hack from a Birdy/TSDZ2 conversion here (1) EP01 : Tongsheng TSDZ2 on Bike Friday Folding Bike ; Electric Bike Laboratory - YouTube

One smaller jubilee clip is on the supporting curved tube and the other is around the radius of the motor threaded through the smaller clip.

Will post more pics later. I'm waiting for more electrical cable, a derailleur drop hanger for a new Shimano set up (older Tern's had a weird derailleur which is defunct now) and a new trigger shifter rather than the horrible rotary shifter.

Guerney, difficult to see what you've done in that pic, have you got one in daylight?

More pics in a week.

Cheers

Mark

 

[StuartsProjects]

@guerney, that picture reminds of Blackpool eliminations as a kid

Nah, not BlackPool but LiverPool

Judging by the number of lights, the bike has recently been stolen off the Eurovision stage.

 

[Mark Waters]

Another though is chainring size. Not sure how many teeth are on the original chainring, but the tsdz2 only has 42t default and woosh warranties up to 44t.

Original was 44t and I've switched to a 44t for the kit, highest recommended by Wooshbikes. And happy to tootle, my speed freak days are over.

 

[Bogmonster666]

Ah, with you now on the jubilee clips.

 

[guerney]

Another though is chainring size.

52T, and if I didn't have to cope with such steep hills, and if I was still foolish and young, I'd have installed 60T by now. Feels like there's enough torque for around 60T on the flat, owing to the bike's smaller wheels, even with the controller limited to 15A.

Guerney, difficult to see what you've done in that pic, have you got one in daylight?

I've never taken a photo of my bike in daylight. Here's an old 30 second exposure snapped in moonlight on a hill, after I'd enjoyed a kebab and coke. The bike has changed and I've replaced the cabling at the front since then, looks a bit tidier now. I left the cables long and slack for easy replacement, instead of cutting to exact size and soldering, which turned out to be a good idea a couple of years ago.

 

[guerney]

@guerney, that picture reminds of Blackpool eliminations as a kid

Nah, not BlackPool but LiverPool

Judging by the number of lights, the bike has recently been stolen off the Eurovision stage.

I've added more lights since! It's horrifying when viewed from the front or back, both of which are bright enough to shine around bends on country roads, so I don't end up slamming into walls of metal and glass on wheels cutting corners at high speed at night. About motorbike light brightness, I think, the front anyway. The rear flashing light looks a tad brighter than those of motorbikes, and much more alarming... but as you can see it's angled down to avoid dazzling.

 

[guerney]

Guerney, difficult to see what you've done in that pic,

I wanted to keep the bike's compactish folding capability, so avoided mounting the battery in the middle, but used the same webbing as the bloke converting his Dahon Jetstream with a BBS02 below. Zipties over the webbing prevents the wires undeneath being pinched; allegedly tidier.

I had to improvise in a hurry, used a palletwood plank, bolted through (bolts have been replaced since, those were all that were available at my local hardware shop), clamped on underneath by a long strip of aluminium, locknuts. It's ugly, but hidden by the two waterproof hi-viz rucksack covers over the battery (because one rucksack cover isn't waterproof enough for hours in heavy rain). I'll get around to replacing the wood with aluminium, which is about 100g lighter, not that weight matters much to me (yet), because I have a big 19.2Ah battery and powerful motor.

Self-amalgamating rubber tape over all the connectors, also used 4:1 self-adhesive marine heat shrink in addition wherever possible.

 

[Bogmonster666]

For anybody who might think Dahon's don't sometimes suffer the same fate:

Dahon Boardwalk: Rust-In-Pieces : Treadly and Me

My bike broke. Completely in half. While I was riding it. This was not fun.

treadly.net

Dahon Catasthofic Frame Failure - dahon Roo - Bike Forums

Folding Bikes - Dahon Catasthofic Frame Failure - dahon Roo - Hey, I wanna share a accident whose happen after a cathastrophic frame failure of dahon roo D7. Riding on Sao Paulo on a major avenue the frame silpy snaps in half, leading the rider to hit hard on floor with some burns and minor...

www.bikeforums.net

But I've seen more posts about Tern bikes and Tern had the re-call. At the end of the day any bike frame is liable to failure, just some designs are more prone to it than others.

 

[guerney]

For anybody who might think Dahon's don't sometimes suffer the same fate:

Dahon Boardwalk: Rust-In-Pieces : Treadly and Me

My bike broke. Completely in half. While I was riding it. This was not fun.

treadly.net

Dahon Catasthofic Frame Failure - dahon Roo - Bike Forums

Folding Bikes - Dahon Catasthofic Frame Failure - dahon Roo - Hey, I wanna share a accident whose happen after a cathastrophic frame failure of dahon roo D7. Riding on Sao Paulo on a major avenue the frame silpy snaps in half, leading the rider to hit hard on floor with some burns and minor...

www.bikeforums.net

But I've seen more posts about Tern bikes and Tern had the re-call. At the end of the day any bike frame is liable to failure, just some designs are more prone to it than others.

C H White, a well known seller of Dahons and other folding bikes and spares, have told me that over the years, their customers have had little trouble with older Dahon folding bikes, particularly those which feature the reinforcement bar above the hinge, also known as a "Rebar", and almost no problems with the Dahon Helios. The Dahon shown (it's got a thudbuster, they don't make those for my bike anymore) doesn't have a rebar.

I'm not too worried. Possibly more likely I'll be run over. It looks old fashioned, but Dahon really should have kep the rebars. Here's another supporting feature for newer bikes, called "Safeline" - basically a steel cable:

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