My rear rack broke.

[PCeBiker]

The whole rack almost broke off the ebike with my battery attached to it.

If it wasn't for this Allen bolt, the rack would have broken off the e-bike.

That bolt hole shouldn't be slotted.
The bolt can too easily slide in the slot regardless of how hard you torque the bolt.
There's too much lateral force pounding on it.

Luckily I had zip ties to secure it enough to make it home,..

I looks kinda bad-ass without the rack and fenders.

I had to strap the rear brake light from rack to the swing arm while I figure out what to do.

I bought this stuff to see what I can make.
I'm going to try my luck at aluminum brazing.
I suck at welding but I'm OK at soldering.
This is almost the same but hotter,..

Amazon.ca

And a bunch of U-Bolts and stainless steel hardware,..

 

[Nvreloader]

PC
What brand of rack, OEM or add on?

 

[PCeBiker]

PC
What brand of rack, OEM or add on?

It came with the bike.
It's a stupid design. It's got a ridged fender that is used as a support for the rack. There's two bolts with slotted bolt holes connecting the fender to the rack. That's all the slack you would need to line up three bolt threads. The single attachment point on the swing arm should just be a hole, so the fender can't slide.

 

[PCeBiker]

I'm outta luck with any kind of warranty,..

 

[Nvreloader]

PC
I have this one on the Wart Hog and it carries 65# on every trip,
never a problem.

https://www.amazon.com/West-Biking-Universal-Adjustable-Reflective/dp/B0154OMGIK/ref=sr_1_3

 

[PCeBiker]

PC
I have this one on the Wart Hog and it carries 65# on every trip,
never a problem.

Yeah, I've been looking at that, but I've got a full suspension e-bike, so I can't mount to the seat tube.

There is this one available, but I don't know how sturdy it is?

It does show a guy sitting on the rack, but he's probably a 65# 4' 2" Chinese guy.

I just spent $67 CAD for a pound of aluminum brazing rods, so I'm going to have a go with them first.

I hope that I don't completely suck at brazing, then end up buying the rack anyway?
That would suck.

 

[Nvreloader]

PC
I would be looking this type of back rack, with the center leg, the front arms could fit you top tabs closest to the seat stem,

Amazon.com

There several with the 3 leg upright legs, plus the front legs for more support..
Hth's

 

[PCeBiker]

I saw that one too, but I don't have a threaded bolt hole for it,..

Plus, I had a huge gap between my tire and fender,..

So,....
I'm thinking of scavenging the rear fender from my Et.Cycle and fitting it to my Voltbike.

I can drop the fender down closer to the tire at the top, and put a spacer on the swing-arm connection point to bring it closer to the tire as well.
That might give me enough clearance for the fender to reach down past the chain-stay to fully protect everything in front of the rear tire?
Moving the fender down and back will push it out behind the wheel, but that shouldn't matter.

I barely had enough clearance for my battery bag with my suspension seatpost, and had to move my battery bag back off the end of my rack.
That extra inch or so of clearance would probably be enough to move the battery a couple of inches forward.
And, it will lower the center of mass of my 14 pound battery too.

The stupid Voltbike fender reduces to a tab that attaches to the swing arm.

The fender should extend lower until it just clears the chain-stay, when the suspension is collapsed. (I'll let the air out of the rear shock to find the clearance.)

I've got crap spraying all over my controller, bottom bracket, and me too.

What kind of brainiac designed that fender/rack ?

What a dumb ass.

PS,..
Chain-stay is a stupid name for that part if the frame.
The "Chain-Stays" aren't there to make the chain stay where it is.

They are there to connect the rear wheel to the rest of the bike.
They should be called "wheel-stays".

Two-wheeled vehicles without chains don't need "chain-stays", but they do need "wheel-stays".

 

[jabberwocky]

They are pricey, but the Old Man Mountain racks are probably the best way to carry around some weight on full suspension bikes. They replace the through axle with a custom one with mounting points for the rack which can handle a lot. Good company with excellent service too.

EDIT: Just noticed you're running a hub motor. Probably won't work.

 

[PCeBiker]

They are pricey, but the Old Man Mountain racks are probably the best way to carry around some weight on full suspension bikes.

Yeah !!
That's more like it.
It attaches to the axle.

That might work for me?
Even if I just find an axle mounted bracket?

I've got a 12mm axle that I can bolt to.
That's a way better spot to mount the rack.
Maybe a couple of these, along with the five 6mm bolt holes on my swing-arm will work better?

The axle and the 5 bolt holes are on the same swing-arm segment, so there's no movement between them.

Either way, I'm going to try and make something first, then in a couple weeks when I've got two broken half torched aluminum racks and a pound of melted brazing rods in the recycling bin, I'll consider that rack.

 

[Nvreloader]

PC
I believe that most of the problem with those racks are the curved corners/bends. You have a 14# + hammer (battery) acting like a jack hammer every time your rear wheel hit a bump, it cracked/broke right at the bend.
Try to use a straight line compression on all the support legs for your next rack.
They make a rear rack, straight line legs that attaches to the rear axle.
You only have the 4 tabs on the chain stay to attach the rack??
Hard to tell from the photo's.
Can you pull back on a photo and show where you have attachment points that can be used, and the rear axle area of angles of the OEM support bars/stays end.
Hard to see any other areas from the close ups.

I don't think you'll have a good success at brazing those alum supports, but try it any way and prove me wrong lol.
ymmv

 

[jabberwocky]

Yeah !!
That's more like it.
It attaches to the axle.

That might work for me?
Even if I just find an axle mounted bracket?

They are generally designed with a replacement axle with machined ends that accept the rack. Very robust. I have one of their axle packs to mount bottles to my fork on my e-gravel. I know several people who have used their racks to setup FS mountainbikes for bikepacking.

With a hub motor bolted on with torque arms I'm not sure if they have anything that works. I do see fit kits for bolt on hubs, so maybe? You should contact them, they are very knowledgeable and responsive in my experience (I had some questions on the install of my fit kit and they responded with detailed, accurate info within an hour or two).

Expect the setup (fit kit/hardware/rack) to be pretty expensive if you do go that route.

 

[jabberwocky]

And yeah, the stock rack design is dumb. Its cantilevering the load on those thin aluminum tubes for no real reason (like, could have put an attachment point further down the chainstay and had a load bearing tube that was much more vertical). That looks like a pretty textbook aluminum fatigue failure right at a weak point (where they crimped and bent the tube to make that curve).

 

[Dave Rocks]

do you need to post that many pictures about a bike rack breaking?

who cares but you . get a new one

 

[Ender]

do you need to post that many pictures about a bike rack breaking?

who cares but you . get a new one

Well I for one, was getting into it. It's an engineering failure on a small scale and at a different level, a shopping vs. repair challenge. The kind of stupid stuff I enjoy puzzling over all the time.

On the engineering side, you can imagine better choices in the design of both the mounting points and the rack geometry that could easily have avoided this. For example, adding vertical cross braces to break the parallelograms into triangles or more standard mounting points.

And on the shopping front, sure he could buy another of the same thing, but it seems likely to fail again in the same way. Or going to a third party brand gives lots of options for the rack, but introduces challenges to mounting a fender.

Anyway, what else are these forums for but troubleshooting these goofy problems with people that can relate.

 

[CanNik]

Was it intended, BUILT to take the weight of a battery if not then NO fault on the rack just the user for using it NOT for it's intended purpose.

 

[BlackHand]

Was it intended, BUILT to take the weight of a battery if not then NO fault on the rack just the user for using it NOT for it's intended purpose.

Easy enough to check.

 

[Mike TowpathTraveler]

Idle thoughts.....

I feel your pain, @PCeBiker. I've never had a rack break on me, but there's nothing like having an on-road failure that wakes you up as to the design and build failures of our bikes. Some thoughts for you to contemplate as I am a "rack guy" who wants the ability to lug as much "stuff" as needed for a trip......

Riv-Nuts. Google it. Riv-Nuts are threaded inserts that "bite" into the host frame material and is held in place by serrated teeth on the exterior portion of the Riv-Nut. I have a Specialized Fatboy with the front carbon fiber fork. I wanted to install front and rear racks on the bike, but I knew there was no means of attaching a front rack to that CF fork. So I searched and found a Fatboy aluminum fork. Next up was fitting the rack (a steel Surly Nice rear rack) to the fork and marking the mounting locations for where the Riv-Nuts are to be fixed into the fork). With the Riv-Nuts in hand, I took the fork to my local, friendly LBS and they installed the Riv-Nuts with no problems. (I did not have the courage to drill out and install the Riv-Nuts into the fork, LOL). Here is a pic of the Fatboy aluminum fork with my new rack installed, pre priming and painting the fork in a 2 part gloss black automotive paint:

Follow those Surly bright stainless rack stays to find the 5mm stainless hex bolt that is holding the rack in place by the riv-nuts. Riv Nuts are what you need and know that about every aluminum framed bike features steel riv-nuts to hold racks, water bottle cages and the like, in place!

Finished product. Now, on your ebike, you can completely scrap that useless rear rack and mounting system; find yourself a top tier rear rack with upright stays top and bottom that are to be held in place with small hex bolts. I think Surly even still makes this rack. It is all steel, features stainless steel uprights and other parts and is proven in world wide long distance touring by alot of cyclists over the years. Keep in mind, like in every bolted-on rack, total weight capacity is held by those small allen head bolts.....

 

[Mike TowpathTraveler]

Part 2:
Aside from the Surly steel racks, the best racks going are the Old Man Mountain racks. They feature constant revisions by the new owner of OMM, The Robert Axle Project folks. An OMM rack will not fit your rear axle cause the OMM design uses a through-axle. Not doable on your rear hub motor bike. But................. your front suspension fork most likely does have a through axle. And with that, you can do what I first did on my Haibike Full FatSix: install an OMM rack using their axle designed for the Rock Shox Bluto. (I do not know what you have for a front axle as per diameter and length; all call to OMM on your part would have to do).

At the time I went with the OMM front rack and axle, I wanted to first install the OMM rear rack. However, there were no OMM Phat Sherpa rear racks to be found anywhere; so it was front rack installation or nothing.

Okay, this is the OMM Rock Shox Bluto rack stays, through-axle, foot mounts. The long quick-release is used to hold those foot mounts tight against the through axle. The through axle is center drilled to accept that long quick release shaft....

Good closeup I did of the finished OMM front rack. OMM has done away with those top stay aircraft clamp-around-lower shock tube design and went with a different, in-house design in the newer versions. I scrapped their plain steel clamps and went with Ancor marine stainless insulated clamps. All hardware used was changed over to stainless. I used stainless lock-nuts to prevent any loosening of hardware. In about 15 thousand miles of riding the bike, not one problem to report. Note the ingenuity of this design where all of the weight of the rack and any gear, is supported by that through axle.

Final result. That Ortlieb Office Bag is not meant to support a heavy battery. Along with finally installing that rear OMM rack, I also went with Ortlieb's E-Mate panniers, that are specifically designed to carry a battery of set width and length. In my case of the Yamaha external mount battery, it was a perfect fit........

 

[CanNik]

do you need to post that many pictures about a bike rack breaking?

who cares but you . get a new one

I couldn't agree more, get real