SAFETY HAZARD - RAD Mission - Chain Tensioner Failure

[JLF]

First, I do love my Rad bikes. I have two, and besides having to constantly true the rear wheels from motor torque, they've been pretty free of issues. (Although last year, my RadWagon initially arrived with a crushed rear wheel, that they promptly replaced).
TIL NOW. I took delivery of a new Rad Mission in late October that had flat tires due to defective valve cores. Rad acknowledged and offered to send me some new tubes, (TWO MONTHS AGO). In the meantime I put down my own $$$, so my wife could ride her new bike.
In a very short time, the Chain Tensioner Pulley Cage ended up rubbing against the spokes. I first thought it was poor design and replaced the button-head screw with a countersunk one to increase the clearance. Yesterday the Tensioner COMPLETELY FAILED and drifted over hard into the spokes. Upon close inspection, the only thing retaining the pulley cage on it's pivot mount, away from the wheel, is a small soft aluminum roll-pin, which wears down and/or shears off after minimal use.
The RAD website already shows a How-To for replacement of the tensioner, which leads me to believe that they are aware of the problem, but are treating it on a case by case basis.
Based on the possibility that such a failure could lock up the rear wheel ejecting the rider and causing injury , I would feel RAD should, at minimum, potentially contact ALL Mission owners advising of the potential risk and provide an inspection protocol.
I personally am currently waiting to hear back from them.

 

[Captain Ron]

Hi JLF,

Thank you very (very) much for the heads-up (cautionary) warning. I immediately checked my Radmission but (so far) everything seems snug and aligned. I guess it's just a matter of watching it carefully ... a waiting game. In the automotive world, I think that this would be called a "product recall" ...

I hope you don't mind, but I "passed along" via cut-and-paste your post (saying that I found it here on the EBR Forum) to two other Rad FB websites ... Rad Power Canada, and Rad Power E-bikes Owners's Group ... and also included the link to the new Rad Power Chain Tensioner Replacement Tutorial ...

https://radpowerbikes.zendesk.com/hc/en-us/articles/1260800194270-RadMission-Chain-Tensioner-Replacement-Guide?fbclid=IwAR1MQC8zxuoOcpY8a5I0u8pby0ebmSS8t0y_npeEl3N-zcmd9Ta8R7Y5Jm4

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[JLF]

Captain Ron. No worries, thanks for spreading the word. I have a good video of the failure, but had no luck trying to upload it. Still no reply from RAD.

 

[Captain Ron]

JLF, is there a possibility that your particular issue with your Radmission's chain-tensioner was just an unlucky "one-off" event ... a totally possible anomaly based on the rare failure of one mechanicalpart or one sloppy factory assembler?

The simple fact that Rad Power very suddenly created that video (showing owners how to remove the chain tensioner and replace it with another one) would naturally make me (and you) suspect the the issue was actually suddenly quite widespread. However, I'm bringing-up this point because nobody else has reacted to my post (sharing your EBR post here) in the "Rad Power eBikes Owners' Group" Facebook page ... and that page has (a pretty significant) 39 000 members. Although I don't think too many Radmissions have been delivered so far, and not everybody "follow" these kinds of pages ... but I suspect most do ...

Whaddya think?

 

[JLF]

That's precisely what I wanted to believe, until I went to their site and found that video. It did take about 50 miles to show up on my wife's bike, but looking at how wimpy and soft the little roll pin is, there will be more. I have yet to even get a response from them. If they end up sending me an identical unit, I'll replace the aluminum pin with a stainless one or maybe tap in a stainless (loctite secured) screw.

 

[Captain Ron]

Thanks for the fast reply. It will be interesting to see how this unfolds. Their lack of a timely response is troubling, if nothing else ...

In the last few weeks on these forums, I think I have learned something of which I was not aware. If I understand correctly, it is not uncommon for these manufacturers to use not-very-tough non-steel fasteners (aluminum bolts and nuts ... and pins, I guess) to secure "stuff" to the aluminum parts of the frame. I think that the only part of the basic Radmission "structure" that is made of steel is/are the forks ... important tp give that smallish bike a decent weight rating. Everything else is typical aluminum alloy.

If a cheap but strong steel "fastener" is over-stressed (or over-torqued) accidentally (or otherwise) into or onto an aluminum structure ... that expensive structure is gonna possibly get seriously mangled.

So, they use aluminum fasteners of "barely adequate" toughness ... preferring to have the fastener fail (break or strip) rather than have tough steel fasteners "do a number" on the crucial aluminum "under-structure" of the bike. Did I get that right? Does that make sense?

 

[JLF]

That all of course makes complete sense. Right now I fully believe that RAD is drowning in their success and can't keep up with customer service. We all know what the long term result of that will be.

JLF

 

[Captain Ron]

That all of course makes complete sense. Right now I fully believe that RAD is drowning in their success and can't keep up with customer service. We all know what the long term result of that will be.

JLF

Point noted. Sometime within the last few hours I read a great anecdote about Kurt Vonnegut and Joseph Heller discussing (as only them two guys can) that idea at a billionaire's beach-house party that they were both attending. I just went back and Googled it.

I found this interesting story in John Bogle’s book, Don’t Count on It:

At a party given by a billionaire on Shelter Island, the late Kurt Vonnegut informs his pal, author Joseph Heller, that their host, a hedge fund manager, had made more money in a single day than Heller had earned from his wildly popular novel, Catch-22, over its whole history. Heller responds, “Yes, but I have something he will never have – enough.”

Incidentally, I notice that Rad Power also offers a tutorial on removing and replacing the chain tensioner on the Rad Runner ... so ... there's that.

 

[JLF]

The Runner uses a completely different tensioner (mounted to an extended arm), and it appears that video is only for pulley wheel replacement. The Runner is also a very new model, which makes one wonder if they've changed production suppliers in Asia.
JLF

 

[RenegadePilgrim]

They have tutorials on everything. I don’t think that’s a warning. It’s just good customer service especially for folks doing their own work.

 

[Captain Ron]

I suspect (and hope ... with a sense of relief) that you may be correct. Thanks for chiming-in ...

 

[JLF]

Finally heard back from RAD. They are sending me a new tensioner. When I asked if it was the SAME as the OEM one that failed, they replied:

"The new tensioner will still be the OEM one. A shop should be able to help you get it installed and set up properly!"

and upon commenting that that was not in my mind a very promising resolution,:

"I can assure you I did read your initial request, did watch your video of the pin, and certainly do care about the safety of Rad riders.
Our engineers thoroughly test our products to ensure their safety. Unfortunately, I am unable to offer a different tensioner to replace the OEM part, as this is all that we stock. If you would like to look into an upgraded tensioner I would suggest chatting with your local shop. They will be able to help find you one that fits your needs."

I'll keep ya posted on what actually shows up and update on it's life expectancy.

JLF

 

[Captain Ron]

Finally heard back from RAD. They are sending me a new tensioner. When I asked if it was the SAME as the OEM one that failed, they replied:

"The new tensioner will still be the OEM one. A shop should be able to help you get it installed and set up properly!"

and upon commenting that that was not in my mind a very promising resolution,:

"I can assure you I did read your initial request, did watch your video of the pin, and certainly do care about the safety of Rad riders.
Our engineers thoroughly test our products to ensure their safety. Unfortunately, I am unable to offer a different tensioner to replace the OEM part, as this is all that we stock. If you would like to look into an upgraded tensioner I would suggest chatting with your local shop. They will be able to help find you one that fits your needs."

I'll keep ya posted on what actually shows up and update on it's life expectancy.

JLF

Hey JLF,

Thanks for the follow-up. We're (naturally) all hoping that one of the components on the original chain tensioner had a rare manufacturing flaw, or was improperly secured/installed at the factory ... which could have caused its accelerated wear and eventual destruction.

Fortunately, after I looked at their related removal/replacement instructions and llustrations, I think it looks like a really simple task to install the new chain tensioner. Y'all will keep us posted, I am sure.

 

[JLF]

Finally received/installed the replacement tensioner from RAD. While the bike is good-to-go, there are more questions than answers about how this came to be and WTF is going on at RAD and the QC at it's suppliers.
First photo shows the new one with a nice new stainless hex set screw, hopefully loctite-secured. The second photo shows the shaft of the OEM tensioner, now disassembled with what I thought was a roll-pin either sheared or cut off, and an empty threaded hole, that may or may not at one point have contained a set screw like my new one. Did this occur during original manufacture? Did it occur during final assembly? Was there a set screw in the fresh hole at one point that fell out because of no loctite? I don't have a microscope handy, but there is no evidence of loctite that I can see. Why two holes in the first place? QC in the asian market sometimes requires close supervision and strict guidelines. I suspect this happened at the lowest level in production where someone maybe missed and decided F-it just snip it off and drill/tap a second hole. I can't come up with any other explanation, and I don't get the feeling RAD cares other than to send me a new one and move on.

JLF

 

[Captain Ron]

Finally received/installed the replacement tensioner from RAD. While the bike is good-to-go, there are more questions than answers about how this came to be and WTF is going on at RAD and the QC at it's suppliers.
First photo shows the new one with a nice new stainless hex set screw, hopefully loctite-secured. The second photo shows the shaft of the OEM tensioner, now disassembled with what I thought was a roll-pin either sheared or cut off, and an empty threaded hole, that may or may not at one point have contained a set screw like my new one. Did this occur during original manufacture? Did it occur during final assembly? Was there a set screw in the fresh hole at one point that fell out because of no loctite? I don't have a microscope handy, but there is no evidence of loctite that I can see. Why two holes in the first place? QC in the asian market sometimes requires close supervision and strict guidelines. I suspect this happened at the lowest level in production where someone maybe missed and decided F-it just snip it off and drill/tap a second hole. I can't come up with any other explanation, and I don't get the feeling RAD cares other than to send me a new one and move on.

JLF

Thank you. Do you know (or have reason to believe) if the new one has a second hole) alongside the one in which that hex-head is now secured? Do you suspect that your first flawed tensioner originally had a hex-head set screw in one of the two (?) holes and that it quickly popped out? And that there were *two* holes because the "first" one was unsuitable and so the assembly-person just added a second hole alongside it and popped-in (not very well) the standard set-screw?

Thanks! (I'm just trying to get this clear in my head.) If the new one has only the one hole, the scenario just described (asked-about) would all make sense, right?

 

[JLF]

As far as I can tell, the new one only has the one hole. And, with the mindset of "if it works don't F-with it", I'm not game for further disassembly to find out absolutely.

JLF

 

[JLF]

I did send these recent photos off to RAD with my suspect speculation. I'll let ya know if I hear more. If "I" we're RAD, I'd want to know and get to the bottom of it, but like I posted previously, I feel they are drowning in their success, can barely keep up, and just want to move on now that my bike works.

JLF

 

[Captain Ron]

I did send these recent photos off to RAD with my suspect speculation. I'll let ya know if I hear more. If "I" we're RAD, I'd want to know and get to the bottom of it, but like I posted previously, I feel they are drowning in their success, can barely keep up, and just want to move on now that my bike works.

JLF

Sounds like a plan!

Thanks for the "closure" ...

 

[Smizey]

I experienced the same problem. Local bike shop mechanic indicated that it’s cheaply made and will likely break again. Has anyone been able to find an off market upgrade. Thanks

 

[Rad and Sad]

Got my Radmission yesterday and my chain tensioner broke on my first ride. Not sure if it got caught in the spoke or what but I'm so disappointed right now. I was pedaling and I heard some grinding noise and then saw the chain tensioner just hanging there on the chain. The bolt that secures the chain tensioner to the frame broke in half and now it is stuck in the frame

Edit: Contacted support through email and they are sending me a replacement chain tensioner. I was surprised how fast they responded as all the things you read online suggest it takes them some time to respond. Will keep you all updated once the new part is installed.

Update: I ended up finding a local mechanic that was able to repair and improve the old chain tensioner with a sturdier steel bolt instead of the weak aluminum bolt. Rides good now. The replacement chain tensioner is on the way but I don't need it anymore.