Is this a problem on my aluminum frame?

MarkJohnston

10 kW
Joined
Mar 25, 2021
Messages
620
I just saw this little silver half moon :banana: near my welds. Do you guys think it's a problem or the structural integrity of my frame is compromised? I don't remember seeing it when I bought the bike.
 

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Can you see if it's only the coating that has cracked there?
Gently try to peel off more to see underneath if there is a fracture in the aluminium.
 
If you thought yours was bad, check my pics out. Just saw it yesterday.
 

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My chainring was rubbing. I have since added some spacers. And now I pray it doesn't fail.
 
If you could take some better photos I could tell you better.

Was hoping for a review of those tires.
 
99t4 said:
If you could take some better photos I could tell you better.

Was hoping for a review of those tires.

So far so good but I've only put 500 miles so far... I'm waiting to rack up some more mileage
 
SlowCo said:
Can you see if it's only the coating that has cracked there?
Gently try to peel off more to see underneath if there is a fracture in the aluminium.

File it down a bit?
 
filing, sanding, etc., will probably remove the ability to tell if it is a crack.

(this is what caused at least one turboprop airplane to crash due to propeller blade separation; the servicers "polished" the insides of the blades, unknowingly eliminating the evidence of the fractures (from corrosion) that were propagating thru them; some info here:
https://en.wikipedia.org/wiki/Atlantic_Southeast_Airlines_Flight_529
but no real details of the specifics; couldn't find those in a minute's search).


Instead, first try getting better more extreme closeups in very good light (direct sunlight often helps), with different angles. You may be able to tell if it is a raised bit of debris, or a recessed crack, or just a chip in the paint, etc.
 
99t4 said:
If you could take some better photos I could tell you better.

Was hoping for a review of those tires.

99 for your veiwing pleasure, I present , the review of the tires...


https://endless-sphere.com/forums/viewtopic.php?f=4&t=116519

Since you guilt tripped me into it. I'll update the thread with time n miles.
 
amberwolf said:
filing, sanding, etc., will probably remove the ability to tell if it is a crack.

(this is what caused at least one turboprop airplane to crash due to propeller blade separation; the servicers "polished" the insides of the blades, unknowingly eliminating the evidence of the fractures (from corrosion) that were propagating thru them; some info here:
https://en.wikipedia.org/wiki/Atlantic_Southeast_Airlines_Flight_529
but no real details of the specifics; couldn't find those in a minute's search).


Instead, first try getting better more extreme closeups in very good light (direct sunlight often helps), with different angles. You may be able to tell if it is a raised bit of debris, or a recessed crack, or just a chip in the paint, etc.

Ok. I'll take off the bag and try and get in there to see. For now my $300 full face helmet came in and hopefully it fits right and not all loose and sloppy like other bicycle helmets. If this snaps I hope the frame holds up enough for me to ride it out. Much easier to ride out a rear frame failure than a front.
 
MarkJohnston said:
Since you guilt tripped me into it...
LOL :D Sorry, I had thought you had said you were going to report back your experiences with them. Maybe it was my wishful thinking? IDK anymore! :lol:
 
99t4 said:
MarkJohnston said:
Since you guilt tripped me into it...
LOL :D Sorry, I had thought you had said you were going to report back your experiences with them. Maybe it was my wishful thinking? IDK anymore! :lol:

Haha I was just joking :lol:
 
Ok will do. This just happened so frock now I need to relace the rim now. If the frame is totalled that's going to be bad. Need this for work.
 

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Bend it back best you can with a block of wood and a hammer, a mini sledge hammer if you have one. One good blow might do it. It could work enough to be fine until your next steep.
 
Skaiwerd said:
Bend it back best you can with a block of wood and a hammer, a mini sledge hammer if you have one. One good blow might do it. It could work enough to be fine until your next steep.

It's cracked and the tire bulges out past it. That's a blow out waiting to happen and it's a $100 tire
 
I just looked at pictures from two months ago and notice this was there then. Doesn't seem like it's gotten worse and I've been doing hard hard riding. I'm going to take a closer look tommorow but I think it's ok. That is the original question. My rim is now busted so I gotta take the wheel off, rebuild. Fun stuff, not.
 
Looking at it in direct sunlight didn't reveal any cracks or anything. Looks fine to me. It's just a raised weird area. If anything maybe the aluminum welds are caving in. But I didn't see any cracks. My phone's pics were all blurry. Trying to get a better one now
 

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I'm just worried because I carry 50lbs of batteries (2x) and a bunch of tools (because I've broken down so many times :cry: ) that that is too much weight to install on an aluminum MTB frame not meant for touring.

I snapped two racks prior to purchasing a tubus rack. The tubus one is steel, the other two were aluminum. Recently I had to take one of the m4 bolts out of the eyelet. When I did that I noticed a bunch of metal particles coming out of the screw hole and upon trying to screw it back , found out it was stripped. I'm using lock nuts and just assuming the next point of failure will be those two tiny screws. But it could snap the frame there at the lower legs of the rack. All depends. Near where I saw that weird divot in the aluminum.

It must be just vibration and the side to side motion pedaling makes. I like to pedal a lot so I increased my gearing so I could pedal at 28mph. Pedaling makes me more stealthy and I like to pass off my bike as a regular bike as much as possible. Pedaling also is healthier because sometimes I run out of breath. That is good for you, cardio n all that.

I cant really get the weight down, so I'm thinking I need a new frame and battery rebuild. Maybe like an old school burly thick steel beach cruiser? I like how they have huge midtube areas. I want to build the biggest baddest battery possible for ebike. Mainly I want it to last forever. Like 50 miles.
 
Side note... sometimes turning off autofocus can help with the blur. It can get confused and keep trying to refocus on the background.
 
MarkJohnston said:
I'm just worried because I carry 50lbs of batteries (2x) and a bunch of tools (because I've broken down so many times :cry: ) that that is too much weight to install on an aluminum MTB frame not meant for touring.
Your worry is justified. 50lb. x 2 is getting into cargo bike territory. They are specifically built for carrying the loads you are carrying. The load capacity is built in, not tacked on here and there like bandaids. From frame material to gussets to brakes tires rims heavy duty racks and connections all purposely chosen for safe weight carrying ability.

Not specifically recommending Surly Big Dummy, but as an example:
https://surlybikes.com/bikes/big_dummy
 
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