Birdbikes

About a year ago, I ordered a cheap ebike from walmart. I had to return it after the first day because my rim broke.


I ordered a more expensive ebike a few days ago, so i want to make sure the same thing doesnt happen.

so last year, my cheap ebike arrived and I put it together myself. I rode it about once or twice for a couple hours. At the end of riding I noticed the front wheel kept touching the brake pads and it wobbled when I spun the wheel.


I took the wheel to the bike shop and they said it needed trued. They called me a bit later and said my rim was shot and I needed a new one.

I don't know much about bikes, so i'm wondering what the cause was.

were the spokes too loose/too tight and me riding it like that ended up ruining the rim? Thats what I originally thought, but I read about people riding bikes with loose or broken spokes all the time and treating it as a small thing, so i'm not so sure.


​​​​​​could it have already been broken and it had nothing to do with me riding it?


Is a wheel out of true or with loose/too tight spokes really gonna ruin the rim from riding it?

Andrew R Stewart 

How can we tell what went wrong a year ago to a wheel we can't see or touch? All sorts of stuff might have happened like shipping damage or initial assembly issue. or a incident we haven't been told about. Andy

Birdbikes

Sorry, I'm looking to get an idea of what it was. I know its not really possible to know for sure. I'm trying to avoid the same thing happening to my new ebike, so i'm trying to understand the causes for this stuff.

i'm just wondering if riding a bike with a wheel out of true like that could be what ruins the rim. I dont know anything about bikes so i'm not sure what happens in these situations.

70sSanO

While it is hard to say what is wrong, it is odd that a nearly new rim would be shot without any explanation. People are able to salvage some pretty far gone rims and use them until they crack or just wear out.

John

thumpism 

Also, did the shop explain in detail what the problem was? I'd be suspicious of the shop's diagnosis of "rim was shot" unless I were there to get the explanation of what was wrong.

aggiegrads

If the rim is straight and the spoked seem tight and even tension, then you should be fine.

the only way I can see a wheel failing in a few rides that seemed ok when it came out of the box would be wildly uneven tension. I suspect that “cheap e-bike from Walmart” is core to the problem.

cpach

Most direct to consumer stuff (with exceptions, like say Canyon) comes with pre assembly pretty similar to how bike shops receive bikes, which is to say they need professional assembly. Most decent bike shops true wheels and adjust spoke tension on new bike builds. A lot of consumer direct ebikes compound this issue by using super thick gauge spokes because they look strong, but in reality it makes it harder for the wheel building robots to get them to acceptably high tension and they're especially prone to failure, ironically. They're also frankly kind of a pain in the ass to work on (weight, the extra drag of the hub motor, uncommon spoke and nipple sizes). The shop might have been simplifying their explanation and the spokes were way too off in tension and they thought that even if they replaced some and or trued it was likely to fail soon. Or if some spokes in a very uneven wheel are way too high in tension then it cause the rim itself to crack. I don't have the wheel in front of me so I can't say.

As a mechanic, I have mostly non-fuzzy feelings about a lot of direct to consumer ebikes due to quality (I'm fine with the competition of the business model, personally) and the misleading impressions the brands make about the ease of user assembly, but if you find something you like bring it to a professional to assemble unless you're interested in building a strong skillset as a home mechanic.

Retro Grouch 

Two bikes, two broken rims. I suppose it could be a coincidence, but my bet is there is something goofy going on here that you haven't mentioned.

cxwrench

^This^ Strongly leaning towards 'operator error'.

Birdbikes

Its not two broken bikes.

It was one broken bike I had last year, and i'm trying to figure out the cause so I can avoid the same thing happening to the ebike I just ordered.

cpach

Bring it to a professional mechanic in the box. Specifically mention you're concerned about wheel failure. Pay them appropriate money. Enjoy your bike.

Geepig

I am with cpach.

The chances of having the same kind of failure is much less than having a different kind of failure. If you are not experienced with bikes, it is good to find someone expert who does not mind talking you through what they have had to do to your bike.

Jmlim

Maybe spoke needs to change

LeeG

Like Andrew said there’s no way of knowing without seeing the wheel. My guess is that a cheap bike has cheap rims and the wheels are trued with minimal labor.. It’s quite possible that one of the ways a cheap bike can have cheap rims is that the rim manufacturer has poor quality control so a batch of rims can have more out of true rims before being assembled into a wheel. An out of true rim will be forced into true as best as possible under spoke tension resulting in a wide variation in spoke tension that use starts to reveal and the wheel goes out of true. The shop you took the bike to untensioned the rim and saw how out of true the rim was and rightly told you the rim wasn’t worth rebuilding using a flawed rim.

So do what cpach says and have a shop go over the wheels. Understand that what makes something cheap won’t be cheap if you are unaware how to make it right.

Eric F 

You already said the answer...

jim_pridx

I wasn't going to say it, but that was my first thought as well.

bitpuddle

There really isn’t enough information in here to have any idea what is wrong.

In general, you wouldn’t need a new rim unless the existing one is cracked. Rims themselves are pretty strong when properly built into a wheel. Do you see any physical damage to the rim (cracks, spoke nipples pulling through the rim)?

We see a lot of issues with ebike wheels being poorly built with cheap, straight gauge spokes. If not carefully tensioned, the extra weight of the ebike combined with poor spoke tension tends to cause spokes to break. Rebuilding the wheel with quality butted spokes makes a stronger wheel. Rim damage is less common, usually from crashing into something or being way over-tensioned.

Every shop doesn’t have a good wheel builder, so you might just be getting some bad information.