Review on Dynamics bike chainless shaft drive
 

There is a lot of discussion over chainless shaft drive vs traditional chain bike. To me, it is just a simple trade-off. You give up a few % of efficiency in exchange for less frequent maintenance and chain hassle free. Just google or wiki it, you will get the answers.

The fact is that there is no such good manufacturer who can produce quality chainless bike. Small manufacturers such as Dynamics make poor quality bike. Famous bike manufacturers with good production techniques and skills are reluctant to make chainless bikes, or just testing it a little by little.

I bought a Dynamics Sidekick 8 shaft drive bike in Feb 2010. Till now it is about half a year. Total mileage is about 2000km. All rides are on nicely paved roads and I am about 72 kg only. Last week, I was totally astonished by the poor bike quality. The bike frame was broken. It is a folding bike, but don’t think that the breakage point is at the folding joint. The actual breakage point is at the bottom bracket which is the most unacceptable location to have frame breakage. You can estimate how poor their manufacturing work is.

Check the photos.

So, don’t buy it.

Whoa!!!:eek::twitchy::notamused: That's pretty frightening...Thanks for the warning. I hope you wern't flying down a hill when that happened.

Around here, anything like that breaking in 6 months would lead to a wildly succesfull warranty claim. Did you try that route already?

Luckily, I am at 15-20km/h when it breaks.

I complained to the maker and they offer to send me new frame, but they don't bear the cost of parts transfer. Actually, I have absolutely no confidence on them and their work any more.

You know, the issue is that how this ridiculous thing happens. Yes, parts wear off. Brakes, tyres, wires, paddles, saddles, etc, we can understand. But the frame is the strongest part of the whole bike. Have you heard about bike frame breakage? Yes, but it is really really rare. Yes, if it has been used for 10 years or more. Yes, if it involved car accident.

In normal conditions, maybe 0.00001% frame will eventually break. In reality, most frames are dumped but not broken. Yes, if frame get rusted it breaks (but this one is aluminium alloy). Yes, if it is totally improper used. But this one is used in paved road all the time. For all folding bike, the weakest point is at the folding joint. You can see from the photo, the folding joint is not brokage. If the bottom bracket can break like this, any locations of the frame can break any time.

Frankly speaking, this is totally unacceptable. Just want to let people be aware of that to avoid accidents.

Sigh!

Aseroiusbiker,

Sorry to hear about your frame - it's definitely not a common issue. One thing we tell our customers is not to overlook the complete package when purchasing a bike. The chainless feature is definitely a selling feature but we have to disagree that there is "no good manufacturer that make quality chainless bikes". We make great chainless folding bikes! =D

Here's a closer look at our hinge system:
http://www.youtube.com/watch?v=fSqJC6iE0yI

I got a reply from a named "chainlessguy", like this in other thread

http://www.bikeforums.net/showthread...m-Review/page2

High quality chainless bikes

Dynamic Bicycles makes as high a quality chainless bike as you can find. In addition to all brand name components, the frames are all 7005 aluminum; all tig welded by hand; all painted by hand. No mass-made china frames are used. In addition, all Dynamic's frames exceed CE certifications for frame strength. So if a frame breaks, clearly some force was put on the frame that it was not designed to take; or this was some fluke in material construction or weld. Either way, it is certainly not typical and has no reflection on the overall quality of the bike. Nonetheless, Dynamic's frames come with a lifetime warranty. So if a frame brakes, it will be replaced. Dynamic even covers shipping costs and rebuild costs if this happens. That's not only good service, that's a lot of confidence in the product.



I can only talk more about the facts as follows:

It is true that 7005 aluminum are strong. But it is also known that 7005 aluminum is difficult to weld. The welding technique of 7005 aluminum shows the quality of the bike manufacturer.

In this case, take a look at the photo. The frame breakage point is right at the welding location between the BB and the frame. This reflects the poor welding and manufacturing technique of Dynamics Chainless bike.

As you said, your bike may be handmade, but it is poorly welded. Your bike may have got the CE certifications for frame strength. But it must be for the frame tubes only (7005 aluminum is strong of course), not for the whole welded bike.

You said “clearly some force was put on the frame that it was not designed to take”. Do you mean normal peddling force?

You said “or this was some fluke in material construction or weld”. Do you want to say someone trying to cause this breakage in purpose? Who will spend US$900 to buy a bike from you and wait 7 months and do so?

Look at the photo, people with clear mind will notice that the breaking flaw is right along your welding line. Obviously, the breakage is caused by the normal pedaling forces pressing down from time to time continuously. Then, your welding joint becomes fatigue and broke. Most importantly, it is only 2000km mileage.

One thing you may be right, it is not typical. Otherwise, your company may have been winded up long time ago. But for breakage like this at just 2000km riding, occasional can be fatal.

Lifetime warranty is nice for reliable frame but it is meaningless for a poor quality frame because this kind of frame breakage can cause fatal accident.

Agreed. That is unacceptable in a bike, especially a folding bike! A decent aluminum bike should have solid welds and the manufacturer should back the warranty.

Does anyone know how to access this other thread? http://www.bikeforums.net/showthread...m-Review/page2

When i try to, i get the response "arthurjune, you do not have permission to access this page. This could be due to one of several reasons: Your user account may not have sufficient privileges to access this page. Are you trying to edit someone else's post, access administrative features or some other privileged system? If you are trying to post, the administrator may have disabled your account, or it may be awaiting activation."

Is this some kind of restricted thread? I'm not trying to edit it.

thanks

The other thread seems to have been removed and now resides in limbo.

This one will end up there as well as you have been offered a full replacement at Dynamic's cost and bet they would like to see your frame so they could analyze what went wrong or see if a certain welder had a bad day.

But you aren't giving them that opportunity and keep slagging them.

Frames break... have you ever heard of Cannondale ?

At one time their nickname was "Crackandfail" as their early aluminium frames were prone to doing just this but they improved greatly.

But they have the best warranty in the business.

You have been offered as much as any manufacturer could ever offer here.

I'd take that offer and see if you can break bike number 2.

The manufacturer is backing their warranty... arthur just isn't taking the offer.

There is a version cached by Google:

http://webcache.googleusercontent.com/search?q=cache:hy62dGcx3bsJ:www.bikeforums.net/archive/index.php/t-191150.html+%22Dynamic+Bicycles+makes+as+high+a+quality+chainless+bike%22&cd=1&hl=en&ct=clnk&gl=us

***** happens, but if you still feel they didn't treat you well get the frame that he offered, sell it and move on to another brand, its hard to build a reputation but its very easily broken, dont take advantage, be fair, your bike broke,you told your story, they are offering a new one, end of story.



:thumb:

I can see where the OP is coming from: company is backing their warranty and reputation with offer of new frame, but customer bears responsibility for cost to swap things over, either in time or paying for services. At LBS, that's what--$75? 100? 150? Especially considering there will be swap over of something out of the ordinary, like a shaft drive? Not something anyone plans or wants to spend cash on, especially since it is manufacturer's fault.

But that's the way of it--manufacturer is following up per warranty, nothing underhanded on their end. Maybe if OP bought bike at LBS, shop would do the warranty swap work for free--that's how our shop works. Another pitfall to buying mail order or online?

Thank you for you guys' opinions.

Yes, the other long term thread http://www.bikeforums.net/showthread...m-Review/page2 seems to be removed for some unknown reason. It has been here for years though! This is a commercial world.

I have no confident on their frame, how can you if you have such experience? but I have not yet refused to accept new frame. To consider accepting or not, I have asked some questions to the maker to make sure they have found out the reason why this unacceptable thing can be happened. I also asked whether the new frame to be sent to me is improved. They stop the communication and does not reply me since Sept. 10 until today because the above removed thread has been getting some attention. Just sending a stock frame of the same patch as the defected one from warehouse is meaningless. On what ground you can say I have to accept the frame? If accident happens you take full responsibility?

"Cannondale", who don't know this brand? So, you wanna compare the early hardworking and struggling history of Cannondale with Dynamics and Dynamics may soon become big brand like Cannondale. Everything could be possible. But this does not mean people should shut up on defects. How you don't know what I am doing is giving them a challenge so they can improve. I can keep silent and the maker just let it go, treating this fatal defect as an isolated incident and fad it out.

I spent an hour or so here to let people know this case. I am not hoping to take advantage, actually what kind of advantage can I take from this? And I don't care whether their reputation will be afffected. Their reputation is on other people's minds but not on my hands. I just speak the fact with actual photo. People will be able to judge the risk they are taking when riding Dynamics.

I let people know the case because I don't want to wake up one day, watch the news and find that someone ride a Dynamics bike and its frame breaks and got a fatal accident. If so, I will regret why I have not done just a little thing or so to avoid this accident. People have the right to know the truth.

And now, people knows, my job is done here.

Enjoy safety riding.