Aluminum vs Steel. Which is better and why?

[SFO]

Corporate identity, product research, and net sales.
Perhaps these are the true drivers of product design.
Maybe a bigger part than we imagine.
Or,

Perhaps ego. :flame:
Why did honda stick with the v4 when the first interceptors were grenades?
People/consumers identify techniques or materials with certain models or makes.
If it sells bikes and builds a unique identity perhaps the purchaser will buy other products from the manufacturer firther building the brand identity.
The science is buying and selling not real manufactured differences because of ti or al or mag.
Just my.02 C.

 

[Boozer]

isn't the XR650 aluminium framed?
if there really is so little difference between steel and aluminium, one has to wonder why BBR goes to the trouble of building machines using Honda frames. Why go to the expense of buying a BBR YZF250/CR hybrid when a YZF250 will do?

 

[James]

Yeah, the 650 is, but the rest aren't.

I can bend a steel frame in no time (fat not talented). I have yet to bend or tweak my CR frames. I can't even break those bolt on footpegs off.

 

[SFO]

Originally posted by Boozer
isn't the XR650 aluminium framed?
if there really is so little difference between steel and aluminium, one has to wonder why BBR goes to the trouble of building machines using Honda frames. Why go to the expense of buying a BBR YZF250/CR hybrid when a YZF250 will do?

Good question!
I have no unbiased answer.
I just fell in love with a naked MV Augusta.
I reckon they are all nuts and bolts, RIGHT?

:flame: :flame:

 

[swingarm]

I have to aree with James. The aluminum frame looks so pretty when you polishe it.

 

[Patman]

Maybe a look to bicycles could give some insight as well. There are three basic frame materials being used in bicycle frames. "Aluminum", "steel", "titanium", each in quotes because there are various alloys. aluminum frames typically have larger tubes which offer the needed strength provide a more ridgid feel because they are "stiffer". Steel can use smaller tubes because it is stronger and it provides a softer ride while still giving the needed strength. Titanium falls between the two closer to steel. Just like in the bicycling world people all want one common thing a strong frame, outside of that some prefer a very stiff and rigid feel and some prefer a little softer "feel" offered by a CrMo frame. None are "better" in the grand scheme of things since "better" is dependat on personal preference.

Now to make things really screwed up my mountian bike is aluminum and I prefer it over the steel frame I had before that seemed springy to me. My trials bike has a VERY stiff aluminum chassis and I like it because trials is more "feel" that any other off road motorcyle form. My new dirt bike currently under construction is CrMo because I liked the overall package and the little bit of flex in it's frame is a non-issue for what I plan to use it for. :)

 

[02CR]

I think its an economic thing.
When you go to the beach and see those guys collecting beer cans, It's not because their foriegners or homeless ...thats the Honda collection team!
personally I believe that my bike was made from all Coors light cans because it is Soooo... Smooth. Check my roost ....does it taste great or is it less filling?

 

[Patman]

Originally posted by 02CR
personally I believe that my bike was made from all Coors light cans because it is Soooo... Smooth. Check my roost ....does it taste great or is it less filling?

So your saying it's only got 50% of the power of a real bike? :p

 

[ML536]

I'm guessing that it is a marketing/brand identity/corporate pride thing as much as anything else. Maybe an aluminum frame can be made lighter than steel, maybe it can't. Either way, I don't think that's why aluminum is being used in this case.

If it is being used for a marketing/brand identity reason, it would not be the only example. Others include, in my opinion, the Yamaha 5-valve head and Ducati's desmodromic valves. Maybe these confer some small benefit, maybe they don't. (I'm guessing that they don't, because the Yamaha streetbikes like the R1, as great as they are, don't make any more power than their 4-valve rivals. The same goes for the desmo valves on Ducatis. Still, I'd like to own either one). Mostly, I think that they are part of the corporate identity. So too with the aluminum framed CRs.

 

[02CR]

So your saying it's only got 50% of the power of a real bike?

No just that it goes like a silver bullet! :thumb:

 

[Boozer]

i am assuming it takes alot of R&D to build a successful aluminium MX frame. Honda must have taken the challenge early, and with three generations of building alluminuim frames, they have it right. Obviously Honda will keep making it better, but it works great now.
The biggest advantage i see is the strength of aluminium frames, and therefore durability. Maby the reason other companys are not following the trend is based purely on demand, just like fuel injection. Everyone knows that even the most basic fuel injection system is far better than its carburettor cousin, but manufacturers have no real reason to spend the R&D to make it work. Yamaha sells huge amounts steel framed bikes, so why would they take a few steps back to develop and improve an aluminium frame?
i'm not sure if street bikes can be compared to dirt bikes regarding frames. dirt bikes go through ruts, stutters and do jumps, so i'm guessing they need to have some flex while maintaining strength.
Also, lets not forget that VOR also make aluminium framed dirt bikes, and they are generally considered to be better than Honda's frames.

 

[ML536]

Also, lets not forget that VOR also make aluminium framed dirt bikes, and they are generally considered to be better than Honda's frames.

Cannondales have aluminum frames, too.

 

[coop47]

Not to be argumentative Boozer - but who says Honda has their frame "right" and who says VOR's frame is "better" than Hondas? It's all 100% personal preference. I rode a 02 CR250 this past weekend - and honestly didn't like the handling traits at all. My 2000 RM250 turns way better than the CR I rode, my RM feels more nimble in the air, it feels lighter and more stable in the rough straights - In My Opinion ;) . Does that mean it's better - for me yes - for everyone else - nope, because while I was riding the CR, the CR owner was riding my RM, it felt heavier to him, slower, etc. Is all personal preference - when Honda starts sweeping the top 10 spots in both the Pro's & Amateur ranks - then maybe I'll buy into the fact that their aluminum frame is "better", more adavanced, better handling, etc., etc., etc.

 

[Boozer]

Originally posted by coop47
Not to be argumentative Boozer - but who says Honda has their frame "right" and who says VOR's frame is "better" than Hondas? It's all 100% personal preference.

you are right. i should have said Honda has a frame that works.
since VOR make their frame in sections and then bolt them together, they will naturally have points to provide flex. im just guessing, but i would have thought this would make them a bit better in terms of feel compared to Honda. then again, the VOR frame could be worse in other areas.

 

[TrailDawg]

Something that hasn't been mentioned yet when the Al. frame was introduced. Honda had lost McGrath(or was that in 98??), they weren't winning races, and sales were declining. I think it would be safe to say that part of the reason for the AL frame was they needed a new gimic to draw customers back to them. They simply adapted the advanced technology from their sportbikes into the CR line and marketed it as a huge innovation and advancement in motocross technology to draw customers back to them.

They played their hand with the Al frame, emphasizing its increased rigidity, lighter weight, etc. Obviously their bluff was called when all the magazines complained about the frames being too stiff and transmitting more vibration, but they stuck with it because of all the $$ they sunk into R&D and tooling costs.

 

[motometal]

it rocks! :aj: :yeehaw:

 

[WR 250]

Sounds to me like TrailDawg hit the nail on the head.

 

[micg]

Pound for pound aluminum alloy is stronger than steel. And more expensive, Honda must not have as big of a profit margin. I have a 2001 CR250 that handles excellent. The best thing about the frame is that it is stronger, and that includes the subframe. Which means that it doesn't get all the stress cracks that my YZ's use to get. I really got tired of welding on the steel frame all the time. I don't think the YZ s use very good steel in there frames any ways. I haven't seen this problem in KTM steel frames. Does any one care to comment on the general quality of different steel frames? Anyhow, I think handling has more to do with the geometry, and how it was engineered.

 

[DougRoost]

Motomike makes a good point on packaging, especially since others have made good points that all of the Japanese crotch rockets use aluminum frames. Aluminum clearly must be much larger to have the same strength as steel, which either makes the bike wider or leaves less room between the rails for the engine and fuel tank. Kawasaki used to note in their "Kawpedia" section of their Web site that street bikes get aluminum frames but the dirt bikes stick with steel for strength. So I bet packaging (and the resulting R&D commitment) is likely why others haven't gone there.

One of the big benefits of the perimeter frame is it opens up the inside for better packaging of the engine and such. It also ties the steering head more directly to the swingarm mounts, which should result in better handling. I'm surprised more manufacturers haven't gone to it. It is interesting that a CR and KX handle so different when ridden back to back, since they're similar designs (in fact Honda copied the KX's perimeter frame in aluminum, as did Gas Gas in Chromoly). This is probably due to the fact that we measure the overall suspension system, not just the foundation, when we rate a bike's handling. After all, Dirt Rider even noted last year that Honda's seat foam contributes to it's comfortable suspension!

 

[marcusgunby]

I used to hate my KXs for cracks in the frames.

 

[Patman]

Originally posted by micg
Pound for pound aluminum alloy is stronger than steel.

So which weighs more a pound of aluminum or a pound of steel?

It's pretty obvious that a pound is a pound BUT it takes a larger amount of aluminum to create a shape with the same strength as a steel shape. Additionally mild steel has a yield point of 36,000 psi and and failure point of 60,000psi so the plasticity of the steel would be 40% where aluminums range is like 34,000psi & 45,000psi or about 24% plastic range. Yes this is all very general in terms of alloys. But let's take the pound per pound idea and run a muck with it. Using a steel frame as a basis if you created the same frame with the same size members in aluminum it would be about 1/3 the weight & 1/3 as ridgid so now where are we?

 

[bigred455]

Just out of curiosity,I had the 97 and 98 cr 250,The radiator shrouds were cutting into the frame pretty good,until I put some backing behind it.Are the 00-03's like this, or did they place the shrouds away a little from the frame.My honest opinion, seems aluminum is a little on the soft side. Come on, I am ready.. :p

 

[Patman]

If I'm not mistaken I think the CR frame runs maybe 4 pounds less than a KX. If I owned a KX I'd just call Jenni Craig and make it a moot point :)

 

[marcusgunby]

bigred my 01 did need to have protection from the rad scoops-i havnt done this on the 02 and so far so good.

 

[yz250roost]

Honda took a hit in the profit department when they introduced the aluminum frame in 97, doesn't anyone recall that they completly CANCELLED all of their amatuer contingency plans just to make up for the change in the frame, the next year the contingency was back on but for a whole year no cash was dealt out at the local tracks because of the aluminum. Saying that honda had no cost change is BS. I also believe that no one follows because honda has found a way to produce it for cheaper, and they're not telling and none of the big comanies want to go through what honda went through just trying to achieve a different material, yamaha spent it's time in R&D refining the YZF's I think we all thank them for that....
Jeff