Broken bottom tube: why?

Could it be that during the weld they had too much heat on the tube which weakened it for the long run since you said it’s around where the bottom bracket was attached?.

Might be human error because all stridas are hand made and not by machine I found out. On my bike i’ve been commuting daily with it for a year so far (12km a day) and everyday I stand on the pedals straight up to do a stretch near the end of my spin. So far I didn’t notice any fatigue or even a crack on my bottom tube yet. It’s a pretty beefy tube so it should withstand quite a bit. I’m 155-158lbs though so I doubt i’m putting enough stress on it.

Not that i’m saying you are heavy at all! :wink:
and keep us updated on how the new tube is working out for you! stand on it and give it some stress to see how it’s working. Just no bunny hops and jumping :slight_smile:

Hi StridaD,

Could you post the photos here?

Thanks! :wink:

Amuro

My commute is roughly the same distance, also daily. Did it for over 1-1/2 years on the 5.2.

Hah! :stuck_out_tongue: Heavier than you, but not that much. Approx. 85 kg, so well within official Strida tolerances!

@Amuro: OK, your wish is my command! :slight_smile:


Thanks StridaD! :wink:

Your weight is waaay below spec of 220lbs. I’m just looking at your pics and wondering how in the world did that break there. It feels as if pedal stress broke it, but it’s not like you can stand on this bike and mash the pedals with your entire weight. at least you have gotten away from the breakage with no harm. Hopefully this is just a one off thing and it’s the first we’ve heard about it on an real strida out of the 8-10 years they have been selling the strida 3-5’s from Ming.

I’d expected the wheel axles to break before the bottom bar. But the axles seem to be holding out alot of my abuse from sidewalk/road riding and hopping those curbs (1-3 cm rise only! :slight_smile: )

Looks like a doggy weld to me … ie the crack comes from the weld which may have been badly done resulting in a microscopic crack where the weld joins the tube - such cracks can make a tube MUCH weaker. Maybe it was a rooky welder ? , who’s work was not 100% checked - maybe robot welding would be better ? (but there again many bike companies promote ‘hand welded’ as an advantage).

At least Strida Stand by their frames, with good guarantees and replace any faulty ones - good result.

It happened to a Taiwanese Stridanut when he was riding in Shanghai.

Another Taiwanese Stridanaut also found a crack on the BB mounting of his Strida.

Photos source:
http://strida.kuso.com.tw/modules/newbb/viewtopic.php?viewmode=flat&topic_id=5146&forum=6

Sounds like you’ll need to check out Ming’s frame warantee :unamused:

I hear they are good at customer service and will ‘do good by you’. When Dahon frames break, they seem to ship out a new frame and then you have to pay for a mechanic to swop over all the bits. So just to be sure I’d ask Ming for a complete now bike.

It seems to be all breaking around that part of the tube. could it be a bad welding job that stressed that joint there?? I better check mine before I start riding in the beginning of my season in April just to make sure everything is tip top. If I ever see a crack i’ll call up ming and hopefully they can mail me a new bottom tube with that new BB that has a massive weld all around it. :slight_smile:.

We’ve had far less frame cracks than the other major folders it seems (dahon, brompton, bike friday(recall fix)) they where all on the seatpost which we don’t have such a design.

Just been offered a replacement bike after suffering this failure for the second time on my Strida 5.0. (Tube replaced under warranty the first time) I’ve had the bike for 2 & 1/2 years.

Interestingly, the second failure was preceded by a persistent creaking from the bottom bracket area. I couldn’t see a crack though until the tube failed catestrophically (for the bike not me). Inspection or the failed tube shows dirt on some areas of the broken surface so I must conclude the were fine cracks present for some time. If your Strida appears to be creaking from the bottom bracket, inspect these weld joints very carefully.

In my opinion the walls of the bottom are to thin and the welding process has created a weak point.

While waiting for a decision I’ve been thinking about reinforcing the bottom tube by filling it with Epoxy Resin filled with glass bubbles to form a syntactic foam. Clearly this would invalidate the frame warranty but should prevent this failure at least. I can’t think of another way to reinforce this tube without introducing stress points elsewhere.

I’ve been told that the replacement bike, Strida SX, is “an improved version with an EN Standards frame.” I can’t find any mention of EN standards in the 5.0 manual or at Strida.COM. If the bottom tube on the new frame has been redesigned and is genuinely stronger I won’t need to worry about modifying it…

Hi tightfisted,

many thanks for your report.

We have here some pics of the EN reinforcements.

EN 14764 City and trekking bicycles - Safety requirements and test methods

It just happened to me again. :frowning: 1-1/2 years after the first incident. Hopefully if they ship me a replacement LT it will have the new reinforced bottom bracket. Can anyone confirm that all new Stridas have this? Or are they still making ones with the same inferior weld?

I’m very sorry to hear that.
You did not mention if you were injured during that action, hope not?

:neutral_face:

Wow, thanks for your speedy detective work, BSA! :smiley: I was also doing some more detective work here on the forums, and there is a thread where Amuro mentions that all LTs in Hong Kong have the EN frame. So maybe we Europeans are stuck with the choice of an inferior frame or upgrading to the SX? Which isn’t really an upgrade if you like having the smaller tires. :cry:

No problem, :blush:

[size=150]Many thanks to J.B. of Vanmoof for the fast reply![/size]

:smiley:

Hi StridaD,

Only Strida 5.2, SD and SX in Hong Kong have the new EN frame. All LTs in Hong Kong still have no EN frame at the moment.

Best regards,

Amuro

Thanks for the clarification, Amuro. That is interesting, AFAIK the 5.2 and SD are not even available in Europe. In fact, I had been led to believe that the LT was the successor of the 5.x series.

I have a happy ending to report. Strida Europe / Vanmoof have sent me a replacement – the SX – and it is functioning well. It has the new EN-style frame, which I am pleased to say does give me an additional sense of confidence, and feels nice and firm. Thank you to Vanmoof for the prompt and fair customer service; special thanks to Joffrey!

As for the SX itself: I am very pleased with the handling of the bike so far. I didn’t really think before that 18" wheels would make much of a difference, but it does seem zippier than the LT. My other concern was that the wheels would be too big for my commute, during which I stow the Strida on the luggage rack of a train, but this was not a problem. My recommendation would be go for the 18" wheels unless you have a specific need for smaller wheels!

Coincidentally, my first proper ride with the SX was on the day when we had our first snowfall here. It was mushy, icy stuff, which has often given me problems in the past. I had been planning on riding my Brompton instead, but it had a flat. :stuck_out_tongue: So I gave the SX a chance, and I found that it felt much more stable in the snow, even with thinner tires! (It came equipped with 18" Innova 85 PSI tires.) Also, I didn’t get any ice accumulating on the belt or the rear freewheel, or getting stuck between the freewheel and the snubber. I think the snubber position was already improved on the LT. I wonder if this was just a happy coincidence, or whether Ming was gathering data from riders in snowy climates. :slight_smile:

I’m glad to read about these good news!

My words - Joffrey is a really nice guy!

A wave for Joffrey…

It’s really a happy ending. :smiley: Congratulations! :mrgreen: