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steel vs aluminum frames

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Posted by: Jon K.---------------------

Do you guys like your aluminum frames?

No speculation needed, if you have an aluminum frame and how you feel about it. Also if you have a steel frame and how you feel about it.

Even better, if you have both, and can express the differences, and which you prefer.

To get started, I will state that all my frames have been and still are steel, and I like them just fine, but have not yet had an aluminum framed anything.

Just wunderin'

Jon K.


Posted by: funktree---------------------

have only had steel here, I do have to say that the honda frames just look damn cool whether they make much of difference or not.


Posted by: OldassKDX---------------------

Why is this in The MX forum? Somebody call the bouncer.


Posted by: kmccune---------------------

'cause Alu frames at present are mostly on MX bikes.

I've only had steel, but I don't have much of a preference. Durability and maint. are big issues with me. Weight ? buy a 2 stroke and forget about it!


Posted by: wardy---------------------

I am not sure what the benifit is from having a aluminum frame, like my old steel frames fine. of course have not went and rode a steel frame machine in a while. they have to sell machines and maybe aluminum is more purty?
Only can change stickers so often.

wardy


Posted by: XRpredator---------------------

There is a poll on this subject:
http://dirtrider.net/forums3/showth...373#post1025373


Posted by: Jon K.---------------------

Quote:
Originally Posted by XRpredator


Yeah Buddy! Lots of useful information there!!


Posted by: Vic---------------------

I prefer steel framed bikes.

Much easier to work on. At least compared to the twin spar frames.


Posted by: Troyboykx125---------------------

I was under the impression that aluminum is a lighter but also stronger metal than steel......aren't most stock handle bars made out of steel? They bend if you breath on them wrong. Also if you notice any device that carries heavy loads but needs to be light weight is almost always aluminum.


Posted by: Someone---------------------

My 01 YZ 250 had steel, and my 05 YZ250 has aluminum, I can't tell the difference while riding. However I just putt on trails, don't race. The aluminum sure looks better and cleans up easier, not to mention doesn't rust from boot rub.


Posted by: rodH---------------------

Quote:
Originally Posted by Troyboykx125
I was under the impression that aluminum is a lighter but also stronger metal than steel......aren't most stock handle bars made out of steel? They bend if you breath on them wrong. Also if you notice any device that carries heavy loads but needs to be light weight is almost always aluminum.


Typically Aluminum is stronger for the the given wt, so they can make it lighter or distribute the wt better. Steel will bend easier, Aluminum usually fails soon after it bends (yield point). Aluminum is stiffer, steel flexes.


Posted by: funkypunk97---------------------

steel versus aluminum: 101

Pound for pound aluminum is much stronger than steel to a point.

However aluminum has to be bigger and thicker to equal the same tencile strength of steel so weight savings is almost a wash. This is why the aluminum frames are thicker and generally of box welded design, compared to the tubed, extruded steel frames.

Aluminum is also more rigid than steel and provides less flex. Steel will flex and eventually bend when stressed. Aluminum usually has a very limited bendability and usually just breaks or snaps when stressed. An example: steel handlebars bend but usually don't snap, while aluminum bars snap and usually don't bend much.

The rigid quality of aluminum in a frame allows for a more precise suspension set up, but at the same time requires a near perfect one to be ridden to its potential. The stiffness provides more feed-back to the rider. Steel is much more forgiving and allows a little more room for error in the suspension set up and absorbes vibration better because it is softer by nature.

For an amateur racer aluminum offers little to no advantage on the track, but at the top of the food chain a guy lik RC could maybe exploit the small benefit of aluminum with a perfect factory set-up.

When all breaks down the benefit of aluminum is small and no magic pill. RC on a steel frame is still faster than anyone on an aluminum frame. But these factories will spend millions to shave one or two pounds. And with the heavier 4-strokes now the standard so to are the lighter aluminum frames.

Maybe the best thing for the amateur and recreational rider is that the frames will never rust. You can keep your bike for 10 years and never worry about the frame getting corroded and getting weak with rust.


Posted by: Jon K.---------------------

My thoughts go back to the '97 Honda. It was the first effort by the Japs to build an aluminum frame.

Reports were that it was harsh and unforgiving. There were also reports of frame breakage, though maybe that was just rumor.

Supposedly the "harsh and unforgiving" problems have been addressed by engineering a degree of flex into the frame, but I want to hear from real people.

I appreciate all the replies.

I have in my mind that perhaps there are people out there that prefer a steel frame, but are getting pushed to aluminum as their choices dwindle.

The progression of that thought has me pondering if there might be an "aftermarket" for 4130 steel frames to replace the stock aluminum frames. Sort of like the Cheney frames of yesteryear. But if everyone loves their aluminum frames, then of course that would be a dead issue.

There could be a bit of custom design in an aftermarket frame, with some fine tuning of stretch, rake, footpeg placement, etc.

Anyone have any thoughts?


Posted by: funkypunk97---------------------

well I don't hear people complaining about the aluminum frames, none of the recreational riders, non of the top racers.

Obvisously there is not a huge movement to keep the steel frames alive so it must not be bothering anyone to much of a degree. So your qestions is an answer in and of itself.


Posted by: larosche---------------------

The Honda Aluminum frame blocks access to the carb. I wanted to play with the carb more on my CRF250X, but I didn't want the pain of getting to the carb. I also had issues servicing the bike with the big aluminum frame providing little room to access the head. The head vent tube was hard to push back onto the head since the frame was "right there".
Handling seemed about the same when compared to my 2006 KTM 200XC-W. They both have very nice forks which are tuned to the bikes.
If it raised the price of the bike, I would opt for the less expensive steel.
RAD DAD


Posted by: Jon K.---------------------

Rad Dad; did the KTM's steel frame influence you at all in your decision to go in that direction?


Posted by: Anssi---------------------

I've only ridden Honda aluminium framed bikes (I have obviously ridden a lot of other bikes but they have all had steel frames) and I have liked the from the beginning (a -98 CR250R). However, that is probably as much due to the suspension as the frame.


Posted by: Al2707---------------------

alu frames are lighter and they dont rust so i think they are better that steel ones, other than that i dont think it makes any difference what so ever, we might as well be talking bout the foam in the seat. lol


Posted by: rodH---------------------

there would be virtually NO market for an aftermarket steel frame:

1. People want what the pros ride, whether there is an advantage or not
2. People want what it the latest and greatest/newest design
3. People want what looks cool
4. People want less maintanance


Posted by: john3_16---------------------

The thing I notice most between steel and aluminum frames when comparing early 90's CR's with my 03'CR250 is when landing from big jumps...The new aluminum frames are much more harsh if you happen to miss the downside of a large jump..When the suspension bottoms on a big jump you get more of the impact transmitted to the rider...
You can really feel the difference on big jumps and in corners...


Posted by: Jon K.---------------------

Quote:
Originally Posted by Al2707
alu frames are lighter and they dont rust so i think they are better that steel ones, other than that i dont think it makes any difference what so ever, we might as well be talking bout the foam in the seat. lol


Anyone have any numbers on the actual weight difference?


Posted by: XRpredator---------------------

Quote:
Originally Posted by Jon K.
Anyone have any numbers?

Eleven.

42

a brazilian


Posted by: Jon K.---------------------

Quote:
Originally Posted by XRpredator
Eleven.

42

a brazilian


3.1416 has always been a favorite of mine . . . . . . .

Really, I would expect the weight savings to be negligible.


Posted by: funkypunk97---------------------

I can't recall for certain, but I believe the aluminum frames are 2 or 3 pounds lighter. But the 4-stroke engine is 4 pounds heavier than the 2-strokes were so it's pretty much a wash in that respect.


Posted by: larosche---------------------

It did have some part of my decision. Keeping the bike running is a big thing for me and the Honda wasn't ready for prime time racing. I think the Yamaha AL frame looks like a better design.


**************
Rad Dad; did the KTM's steel frame influence you at all in your decision to go in that direction?


Posted by: Troyboykx125---------------------

i think i read that aluminum is 35-45% lighter


Posted by: Micahdawg---------------------

Sorry, no experience...just a little speculation.

i've kept an eye on the aluminum framed bikes and weight differences somewhat. I've been pretty surprised to see that the weight savings is pretty negligable. Seems like 2-3lbs difference between another brand's steel framed bike. Immediately I chalked it up to the much thicker aluminum design. (if it's half the weight, but TWICE the frame...you know)

To me, the only reason i would opt for an aluminum frame is because they age better. I keep my bikes until they are 7 or 8 years old and by that time a steel frame usually looks like poo. Meanwhile an aluminum frame still looks pretty good IMO.

I think it is interesting the aluminum "snap" vs. steel "bend" though. And when applying it to handlebars...seems very true. Therefore, just thinking of other things like footpegs that will sag on a steel frame, I guess they could "snap" before they sag on an aluminum frame. It also makes sense that the extra rigidity would make for more of a "shock" to transfer through the frame.

Looks like there are pluses and minuses to each side, but for all out competition, the rider is still more important than frame material.

Micah



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