Which Is better Aluminum or steel frame

Discussion in 'General Questions' started by need a honest dealer, Apr 26, 2010.


Aluminum frame or steel frame?

Poll closed May 3, 2010.
  1. Aluminum frame

    0 vote(s)
  2. Steel frame

    13 vote(s)
  3. anything else not covered here

    0 vote(s)
Multiple votes are allowed.
  1. I wanted to know which Is better for motors on a bicycle.An aluminum frame or steel frame?Any any reason why It Is.

  2. I voted steel.Even though It can rust I figured It would absorb vibration and be stronger than aluminum.Correct me If I am wrong.
  3. Happy Valley

    Happy Valley Active Member

    Other. Titanium......just kidding:D

    Short answer: steel, specifically butted, 4130 CroMoly. Steel is real and generally holds up together/better as a donor frame for motorizing. (That said, there are and I do own some high quality 7000 series aluminum frame MBs)

    It can be useful to remember we are using frames, generally, that were almost exclusively and originally designed to be bicycles. (unless someone is building proprietary frames, of course) I say that because steel bicycle frames evolved to aluminum bicycle frames with the idea they would be strong enough for that purpose and the main advantage was to save weight.

    Also, there were different grades of steel used in bicycle frame building over the years just as there are different grades of aluminum. A couple very pertinent components of this equation comes down to price IE: cheap vs good, and manufacturers origin. For example, a cheap aluminum frame welded in China is nowhere near the same quality as one made in Taiwan and neither as good as one made in the US. Of course, expect to pay (a lot) more each step up that ladder.

    This is why I generally prefer and suggest, particularly if costs are an issue, it far better to look for a used or yard sale CroMoly steel frame bike, preferably of certain vintages, over buying almost any new bike at a big box department store..........better material and importantly, far better welds.

    BTW, it is a good idea to treat steel frame interiors with readily concocted homemade rust inhibitors, something easily accomplished during the build phase.
    Last edited: Apr 26, 2010
  4. Huntington

    Huntington Member

    either, a steel frame will be stronger but you have to remember there will be more weight. I have had good luck with aluminum, even the cheap wallmart ones.

    I currently have a steel frame MB, it rusts but it is a nice strong bicycle.

    Happy Valley pretty much summed up everything you need to know.

    One more positive about steel, easier to weld, if you need to add a post or welded motor mounts.
  5. G-Superior

    G-Superior Member

    i voted steel bacause its easy to repair if damaged, easy to weld, cheap, if it rusts just paint it again and so on, but it will be abit hevier than aluminium. BUT i prefer heavier bikes because when you start geting up to 30, 35 mph it will not get pushed(or not as much) to the other side of the road if a strong wind comes from the side, AND sometimes you can add even more weight to it to prevent that, :thinking: its a typical modification that people do to 50cc racing bikes so it can grip better in the corners and also a better center of stability and much less drunk driving from one side to the other of the track due to strong winds:D Remember that those bikes have power to spare so it really dosent matter a bit more weight but if you do that to a HT you will probably not be happy:rolleyes7: not funny to pedal up hill just because you put weights on you bike :sweatdrop: and not easy to stop with all that mass:whistling:
  6. Fabian

    Fabian Well-Known Member

    Steel frames are slightly more idiot proof for those people who over tighten their mounting clamps on an aluminium frame.
    Once thin walled aluminium is damaged it won't be long before a fatigue crack develops in that area. The resulting scenario is a motored bike that splits in half - gets very messy.

    There is nothing wrong with aluminium in itself, it's just that you do need to exercise great care and be vigilant in inspecting the frame to prevent clamps abrading the surface where stress risers can form that allow stress cracks to propagate.

  7. G-Superior

    G-Superior Member

    thats true!
    safety inspections before every ride! (even on steel frame please:rolleyes7:)
    aluminium is very britle (not always*) when it gets a small crak it wont take much more to snap in half and then you will get stopped by our face which is not very nice:icon_cry:

    *there are some aluminium alloys that dont snap straight away or crak they bent and are like red hot metal it rather bent and twinst than snap, but i have never seen it on a bike:thinking:

  8. meatwad

    meatwad Member

    Mild elcheepo steel. Aluminum does not like vibrations, Aluminum bikes actually have a shelf life.

    As for cromoly it's hit or miss. It is a better steel but the reason they use it is to be able to make the bike lighter by using thinner tubing. It seems counter intuitive but "butted" does not mean that the tubing is thicker where the tubes connect but thinner everywhere else. Triple butted gets even thinner in the middle. That way the frame is lighter . Not exactly what you want either. However depending on the manufacturer it is probably more common that a cromoloy frame is better constructed and welded than a mild steel.

    Bikes such as the electroforged Schwinn cantilever frames and most cruisers from the early 60s on back are the best choice IMO.

    I havent taken a good look at the current chinese made mild steel frames to give an opinion on those.
  9. chefdouglas

    chefdouglas Member

    steel's heavier but the engine is doing the work. It's stronger and can be welded and customized more easily. I've seen vibration cracks in aluminum but not steel bikes.
  10. Huntington

    Huntington Member

    If you have not bought a bicycle yet, you may want to consider the GT2 by Grubee. USA Bicycle has it on sale for $315. Its a steel frame bicycle with suspension forks, heavy duty wheels, and threaded sprocket mount, as well as a built in gas tank. Well worth the money. I bought mine when the price tag was $550, wish I would of waited but o'well.

  11. meatwad

    meatwad Member

    That looks like a great platform.