Bike recommendations? Alu vs Steel

[Deepkimchi]

I'm thinking about buying a new bike. Getting too fast for standard brakes so I thought I would get a front disc brake model. I had bent my stays slightly during motor installation (wheel tilts about 1/4 "), so I did not just want to replace the forks.

I also wanted suspension front and rear. The Korean shops mostly have Aluminum frame bikes.

I have a rear mounted 5304 running 80V. Wanting to go for 120V. Will aluminum work with a good torque arm?

APO (Army Post Office) has a limitation on package size, so I don't think I can order a full bicycle on the internet. Maybe just a frame and forks, but did not want to spend over $200 - $300 doing this. Most stuff I looked at was expensive. :|

Any ideas?

 

[Drunkskunk]

Steel is more forgiving than aluminum, and small cracks, or repetitive stresses aren't much of a problem. Steel will bend out of shape long before it fails giving warning that a part is in trouble.
Aliminum bends little, then breaks.

Now all things considered, a Good aluminum bike frame is as strong as a steel frame, but you won't find a good one for $300. I'd trust a cheap one just fine for a hard tail pushing 1200 watts peak, but beyond that, I'd want something with a proven record. beyond 2500 watts, you're going to want something like a branded and proven downhiller.

 

[AussieJester]

I'd want something with a proven record. beyond 2500 watts, you're going to want something like a branded and proven downhiller.

Would want this period (well..unless your using a 200watt motor) As Drunkskunk mentioned ali doesn't give alot of warning unlike steel...it just snaps. I wouldnt trust the cheapo ali bikes as far as i could throw one, the grade of aluminium wouldnt be up to the job IMO ... If 300 bucks is your limit for a bike i would go with steel over ali just to be safe

KiM

Apprentice Gangsta 8)

 

[liveforphysics]

If you plan to be making modifications to the frame, steel is a much better option. If you are going to leave the frame un-modified, a heavy-duty aluminum bike frame, like something designed for downhill racing would hold up fine. Some of the strongest frames in the world are downhill aluminum bike frames, but it is not a modding friendly material due to welding removing the heat treatment, and bending causing work hardening and stress riser points leading to cracks.

 

[Deepkimchi]

Reckon I'll have to run around Korean bike stores with a magnet. Just thought that if I ordered a frame and forks, would have to make sure it fits the crankset (Korean metric?) and handlebars....

more reading.....

 

[dogman dan]

I haven't yet seen a good full suspension frame with a rear steel swing arm. Given what you want to do, looking into having a swing arm custom made to copy the aluminum one is not a bad Idea. However, an easier solution might be to get a motor with an extra long axle, so some really nice thick custom torque plates could be installed on top of the stock dropouts. I'm picturing in my mind something like a plate with two arms on it, secured to both of the rear stays, and one on each side. I have no Idea if a cheapie bike's steel rear swing arm could be installed on the frame of a nicer aluminum bike, but it might be worth looking into too.

 

[OneWayTraffic]

Many of the cheaper Korean hybrids have steel forks on Alu frames. Of course the cheaper ones are all steel. It's not high quality steel though. There are a few chromoly bikes out there, I was in the Homeplus near World Cup Stadium on Saturday and at least two of the MTBs there were chromo with decent componentry. Roughly 500,000won or so I think. That's close to $300 these days.

You definitely need to go round the shops with a magnet. Most bike shop guys know the English word Aluminium, but few know steel, or chromoly funnily enough.

I did a Google search one day for mountain biking in Korea and I found a list of bikeshops where they speak english. Have a google and see what you can find.

I was going to electrify myself in Seoul, but I've decided to wait until I go back to NZ and get a good kit from ebikes or similar on a bicycle that I can trust.

 

[wrobinson0413]

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[lepton]

I used an aluminum Specialized FSR XC (full suspension) for about a year with an x5 motor. I made a torque arm out of 3/8" thick 6061 aluminum that went from the motor axle to the disc brake mount. I figured since I wasn't using the disc brake in the rear, I might as well use the mount since it should be strong enough to support enough force to lock the rear wheel. Never had any problems.

 

[slayer]

i have a frame rocky mountain slayer for sale if you re interested. i had to change my frame cause it was too small. i kept all the component, transfered to a rocky mountain spice that is lager in size ...i would say that the slayer frame is good for 5 foot 7 to 5 foot 11
if you re 6 foot and more it is a little bit too small . i rode it like that for a couple of year and now i find my new frame better for me



it is made of aluminium and i trust a well made aluminium product did you know that the gt40 ford is all aluminium. and like every product there is quality and would not count out a product cause someone think all aluminium is the same quality


now if you look at the slayer bike it is worth 3,200 dollars canadian and the gt40 well it is over a 100,000 dollar product

and you see the swing arm is removable and if you want you could just make a steel swingarm just the one below were the wheel attach or both uppper and lower arm if you feell like it