Another broken aluminum frame - Surface 604 Elements

markz

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Surface 604 Elements
BSO bike chain stay broke at the curve next to the seat post.
My bet would have been the top tube cracking at one of the holes in the frame for cable. Which is the whole reason I placed the 36V 20Ah battery on the rear rack.

Will get it reinforced and welded.



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Might as well reinforce the other side. Start looking for a replacement frame. :shock:

Would worry about metal fatigue. Aluminum does not like to bend if it's flexing a bit then you could end up with a break just past the patch.
 
Ah good point I never thought about reinforcing the other side.
The other side would have been stressed with 80km riding on a cracked frame like that.
I will have to see what custom motorcycle shops will price me. Then random Kijiji online classified welders will price it. Then fabrication shops vehicles, industrial fab etc.

ZeroEm said:
Might as well reinforce the other side. Start looking for a replacement frame. :shock:

Would worry about metal fatigue. Aluminum does not like to bend if it's flexing a bit then you could end up with a break just past the patch.


:wink: I know eh, just wish I got free government money, whether covid or not... not a penny for me. Should have looked into how to milk it.
Trikes are to wide for me.

goatman said:
time to part with some of that oil money Z and get a trike


There is an abandoned bicycle I found today nearby in an alley.
I am giving it until dark before I go back for it.
It looked like a weird, V shaped fs (like the pic below) but I saw it said Specialized. I always wait and go back for them as a courtesy. Plan is to swap the fork and figure out the rear suspension, just take the coil out and add a pair of 1/4" steel plate, then look for a replacement 700 or 800lb spring that fits, down to 291 lbs today so well on my way to 250lbs, lost 90lbs total in a year so going fs is a realm of possibility today, but not at 380lbs.

The I found is probably older, not as many smooth curves on it. Its not a score, as its fs, I'd bottom the stock shock out. I prefer cruiser style with longer wheel base, dont matter if its fat or townie electra type.

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The one I found looks more like a 1999 Specialzed FSR


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It's almost like traditional frames with straight chainstays were worked out for a long time and became traditional because other variations weren't as good. Or something.
 
I am current with my taxes. 250lbs is doable, another 40 is all.

ZeroEm said:
Don't want to drift off topic. filed taxes just to get some free money. Did you try that?
Get down to 250lbs you will be lighter than me. 8)
markz » Oct 24 2021 6:57pm

:lol:
Yeah the fat bike is stripped of all e-stuff. I have a Trek hybrid, 700c wheels, though v-brakes wont line up, hub will fit in back but I start breaking the spokes easy. Rear hub (135mm) lace job isnt strong for the rear, but has held up fine on the front because less weight on it. I've had the rear hub on the Trek, front brakes work, chain is off, no rd but have one. I am debating whether to rock on over and get the 1999 Specialized FSR or not, see if my fat fork fits it and be able to ride tomorrow.

nicobie said:
Whatever you do, don't let Curtis get near it with his Weller.

:mrgreen:


I had to re-read that to see if its one of your subtle posts or not but I get what you mean now. Straighter chain stays from bb to rear drop out would be stronger then wide, fat bike that flare out from bb to the rear drop out. Say a 110mm rear drop out single speed, vs regular 135mm rear drop out for most other bikes, vs fat 180mm rear drop out with a 160mm hub installed, so a pinched in rear dropout. I do pinch in the gear side, the side that broke. So a couple of factors here, the weight and vibration of the 36V 20Ah battery on the rear rack, my weight, and a pinched in rear drop out.
Looking at the pic - Do you think its a weld defect? Last pic, 3rd pic. Could have started there and grew.
Who knows, it happened.

Chalo said:
It's almost like traditional frames with straight chainstays were worked out for a long time and became traditional because other variations weren't as good. Or something.


Here are pictures I already took, posted them in the other thread, but will do the same here.


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The right chainstay carries not only riding loads, but hundreds of pounds of chain tension. It doesn't make structural sense to put those loads on a wishbone stay-- let alone a lopsided one like that, with a huge reduction in section partway along.
 
I think the problem is the rear was aluminum and not very big. My trike is mostly Aluminum, just the rear fork is chromemoly. It's a rear suspension. This is an issue with most bikes are not made to handle fully grown men. The recumbent bikes/trikes all seem to have one weight limit 260lbs. This is why i'm wanting to get a tandem and reconfigure it, built for two.
 
I don't pedal much, but yeah its normally designed for those pedaling loads normally.

Anyway I hope it doesnt cost to much to weld and reinforce the break. I will have to get on that quick. Might be a high work load for those with aluminum welding skills these days, mobile welders. I see $75/hr with 2hr min, might save something if I bring it to him.



Chalo said:
The right chainstay carries not only riding loads, but hundreds of pounds of chain tension. It doesn't make structural sense to put those loads on a wishbone stay-- let alone a lopsided one like that, with a huge reduction in section partway along.



I will have to measure the thickness of the aluminum.
On my way to pick up a free bicycle, hopefully its not too buggered, hopefully its just a person in a $500k home getting rid of a perfectly fine, operational bike and it wasnt dumped with a broken something or other. Specialized with a big sticker "Nascar" might not be stock, with a Mercalli Downhill fork with 2 bridges, cant be spread for 135mm hub.
Live link will end - https://www.pinkbike.com/photo/6246412/
The bike needs a lot of work. Will post another thread with pics.
Fat bike is getting welded.
Damn mine might be an old big hit.



ZeroEm said:
I think the problem is the rear was aluminum and not very big. My trike is mostly Aluminum, just the rear fork is chromemoly. It's a rear suspension. This is an issue with most bikes are not made to handle fully grown men. The recumbent bikes/trikes all seem to have one weight limit 260lbs. This is why i'm wanting to get a tandem and reconfigure it, built for two.
 
Congrats on the progress. At 250, you should be able to ride a stronger bike without so much breakage. But you need to look at steel bikes IMO. Nice find on the old FSR though.

I think eventually, you should look into some kind of longtail bike. The big deal with these is that the seat is midway between the front and rear wheels. Traditional bikes carry much of your weight, whether sitting or standing, on the rear wheel. Every bump has to lift your weight a few inches.

With a longtail cargo bike, as the front or rear wheel crosses a bump or pothole, it lifts only half your weight, while the seat just gently rocks forward or back. It just about eliminates wheel bending, without any suspension parts to over stress.

You would want one made of steel, even if you have to weld it yourself. If you can locate an extracycle attachment, even better. But a real good first project for learning to weld with a wire feed welder, is to make a similar bolt on bike lengthener, out of a steel, MTB rear swing arm.

See bolt on longtail in my signature below.

In the long run, learning to weld is going to pay off for you. You'll be able to build stuff you can't buy for any amount of money. And make it from scrap bikes. Look for dead bikes with good cromoly tubing in them, to cut up for stock. Or use cheap mild steel in large enough amounts to make a frame that can carry 500 pounds with ease.
 
orange frame looks scary to me
obviously frame broke in weakest spot, this horizontal fork is really too small in diameter.
but it all depends where did you ride ?
example:
I never jump down the curb under my own weight, always get off bike
 
I dont ride fast, 25-35kph on pathways, sidewalks, roads, no jumps, very little curbs.
The side that broke is the side I squeeze in for the undersized 160mm for 180mm rear dropout width.
 
I dented the frick out of my seat tube, when the swingarm hit it one day on the crash. Bent the ( cheap rebound adjustable rockshox) shock rod and blew the shock. Traveled longer than it was supposed to. Hit the edge of the road... Big dent there now. Was not supposed to do that, I have no idea how the swinger hit the seat post but it did... like an inch past the travel it was supposed to have... I look at it and it doesnt make sense... The shock rod bent right at the end, where it screws into the retainer plate and rebound adjuster.

That crash hurt too, real bad. 35mph lowside flicked into a turn.. and whoosh out the bike comes, from under me, smack in to pavement... we slid ( more like thummped) into the ground and the edge of the road. Couldn't breath for minuets. Bike hit the rocky grass at teh side of the road.

Two people stopped and aked if I was OK. Lol.

It even held where I had welded, on the seat stays, two years prior.. all the force was right on my welds. They held. They always think about the compression, but they never figure the rebound force when designing these high end suspensions.

I was jumping five, six feet, then the fork was bottoming out on my battery.

I am redesigning the battery so I can jump higher. Lol. Yall getting off the bike to go down curbs, I slam down every set of stairs within range..... that I can find.. then up too. Thunkachuggathunkkachuggathunkachugga

Somethings gonnna snap one day on my bike. Its got to.. Then another old neglected suspension frame comes off the wall.. Get built. I got two in line to go.
 
The 604 bike I bought lasted a year. My everyday bike after my accident, I bought it used. There is another 604 non ebike for sale on Kijiji online classifieds for the past 2 years from a pawn shop, they still want $895 and the brakes still havent been adjusted.

I am very interested in what the welder guy on Kijiji wants to weld it, sent pics, and found out its 6062 aluminum.

https://www.thefabricator.com/thewelder/article/aluminumwelding/aluminum-workshop-welding-6061-t6-without-filler-metal-choosing-shielding-gas-for-gmaw
In fact, 6061 and the other 6XXX series alloys are relatively sensitive, and it isn’t uncommon for people to have cracking problems with them.
 
Yeah I have a 7005 Aluminum bike. I think its stronger or something. I always have a choice of pure Argon or Argon/Co2. In the shp. I used Argon/Co2 to weld my 7005 frame on the bearing mounts. Paid 9$ for that frame. Cracked where someone had tried to shove a bearing to the wrong hole too hard I think... A bearing mooring was cracked when I got it.

"7005 is an aluminium wrought alloy[1] used in bicycle frames , due to its relative ease of welding it does not require expensive heat treating "

I also have a 2015, 6000 series Banshee.. that already broke its neck.
 
DogDipstick said:
Yeah I have a 7005 Aluminum bike. I think its stronger or something.

Nope, it's about the same strength as 6061 aluminum. The advantage it has, is that it solution heat treats at air cooling rates after welding (in bicycle-ish cross sections). It still benefits from artificial aging, but it saves an expensive step for manufacturers to not have to roast the thing at 990°F after it's been welded.
 
Chalo....
C'mon man. 7000 series is made to be stronger than 6000 series..


7005 :
Tensile Strength, Ultimate 350MPa 50763 psi
7075:
Tensile Strength, Ultimate 675 MPa 97900 psi
Tensile Strength, Yield 625 MPa 90600 psi
6061:
Ultimate Tensile Strength 310 MPa 45000 psi
Tensile Yield Strength 276 MPa 40000 psi

7005 is nearing ( stronger than some) mild steel.
Mild steel is 400 megapascals (to about 800 MPa )
Tensile Strength, Ultimate 420 MPa 60900 psi This is the value for AISI 1020, a mild steel. Values can range from 295 - 2400 MPa, depending on composition and heat treatment.

However, pound for pound, the steel will be stiffer . Whats 10,000psi anyway. Lol. Bah.

7005 is a very very strong aluminum, budz. Very will known for its strength ( its brother, used in airplanes for this strength traditionally , 7075) (7075 is notable for its high strength-to-weight ratio and improved strength over 6061. Because of this, 7075 is largely used in aerospace, marine and transportation industries. Any industry where high strength and light weight properties are critical, this alloy is preferred.)


I know my metals a little, friend. 7005 is certainly stronger than 6061.
Chalo said:
DogDipstick said:
Yeah I have a 7005 Aluminum bike. I think its stronger or something.

Nope, it's about the same strength as 6061 aluminum. The advantage it has, is that it solution heat treats at air cooling rates after welding (in bicycle-ish cross sections). It still benefits from artificial aging, but it saves an expensive step for manufacturers to not have to roast the thing at 990°F after it's been welded.

As BANSHEE Bicycles also agrees with me: For this is how they put it: For they seem to like the 7005 alloy too....

13% stronger, 55% more fatigue strength, 4.5% stiffer: <SHRUG>

Hmmm Maybe I will try to weld my broke Banshee but I swear i read that it was 6061 somewhere. Too bad I cannot tell alloys from one another . Not even my XRF will.


Superior Alloy

All our frames are made using 7005 T6 alloy tubes and forgings. While most other brands use the cheaper and easier to handle 6061 T6 option, we choose to use 7005 T6 because it has superior properties which results in superior frames.

Ultimate Tensile Strength: The measure of the maximum load that an object/material/structure can withstand without being elongated, stretched or pulled. As you can see the tensile strength of 7005 T6 is 12.9% greater than 6061.

Tensile Strength, Yield: The stress a material can withstand without permanent deformation.

Fatigue Strength: The highest stress that a material can withstand for a given number of cycles without breaking. The figured below represent fatigue strength for 500,000,000 cycles (good luck trying to clock up this many pedal strokes!). 7005 T6 has a 55% higher fatigue strength over this number of cycles.

Also worth mentioning that 7005 T6 is 4.5% stiffer than 6061 T6… just saying!

https://www.bansheebikes.com/7005-t6


Mmmmm graphics.
 

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DogDipstick said:
Chalo....
C'mon man. 7000 series is made to be stronger than 6000 series..

7005-T6 yield strength is 42 ksi. 6061-T6 yield strength is 40 ksi. In my book that definitely qualifies as "about the same". Because manufacturers use 7005 to skip the solution heat treatment step, the heat condition is always going to be slightly left to chance, too, so in a bike frame it's not likely to be perfectly in conformance to its T6 spec.

Nobody uses 7005 for its strength, regardless what the marketing wankers might tell you. They use it because they can get 6061-T6 strength with one less step in the manufacturing process. The frame won't be lighter, won't be stronger. It's just cheaper-- which is good. Everybody likes that.

7075 aluminum is another thing entirely. It's nice material to machine, and crazy strong, but you can't weld it. My favorite non-weldable alloys in the 7000 family are 7050 and 7040, which I got to know by being close to Boeing Surplus. They give up a little strength compared to 7075, but they hold almost no internal stress at all. You can machine away 95% of the mass of your part, but when you release the piece from the vise or fixture, it's still perfectly flat on the table. And they cut with an amazingly clean chip.
 
markz said:
The side that broke is the side I squeeze in for the undersized 160mm for 180mm rear dropout width.
Is that why they tell us not to bend the rear triangle on aluminum bikes? Steel is ok to do that but not aluminum because it is apt to crack. Am I right?
 
That was just a cheap frame, and a big rider.

Good frames are not always expansive. Only you need to watch and wait for one to come at a good price.
 
BSO + 350lb rider (380 Oct 2020 - 294lbs Oct 2021) which is when I bought it used a year ago.
I bought it like with the smaller hub not knowing until I had a flat tire. Yes I rode it, it shifted and braked fine, the seller gave me $50 off coz I played the I only have $100's game. :lol:

Yeah its a bicycle shaped object, a step up from Walmart maybe on the same level as BikesDirect but they dont ship to Canada.

Another thing to note, if you missed it that the bb is odd extinct 90mm which you can't buy anywhere. Ebay had a 90mm take off from a bicycle store owner who has 9 for sale, 4 sold. The axle is to short and hits the chain stays for the 604. I looked into wide crank arms the kind gas bikes use.
Solution as Chalo mentioned is BMX crank $$$$ or Mid drive crank (Luna/Cyclone-TW).

I actively looked for a 180mm hub, with 6 bolt disk mount but they were usually $50+$40s/h. ModernBike had one for a good price but was sold out.

99t4 - You could be right, explained above. Steel is ideal, if there is such a thing as a cruiser, fat bike in steel then add to my wish list 3x7 and decent price and used and I am all over it. Am I spending time looking on the online classifieds? no.
99t4 said:
Is that why they tell us not to bend the rear triangle on aluminum bikes? Steel is ok to do that but not aluminum because it is apt to crack. Am I right?
 
It's getting harder to find Steel. They are still out there. Think about a cargo bike or tandem. I know your riding style is for the more normal Bike.

Maybe Chalo will build you one. :shock:
 
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