Good question regarding Alum Frame in the 06 YZF450

[Ga426owner]

This is from Motorcycledaily.com today...............

Why is Everts Still Racing a Steel-Framed YZ450F?

By Dirck Edge

With everyone expecting Yamaha to introduce aluminum-framed four-stroke motocrossers next year, why is World champ Stefan Everts still riding a bike with a steel frame (pictured above)?

You may recall that Everts tested an aluminum-framed race bike a few years ago, and switched back to steel. Aluminum-framed YZ four-strokes have been spotted racing in Japan, and looking like pre-production models. Normally, you would expect the MX1 champion to be aboard next year's pre-production machinery.

We should know within a few week's time whether Yamaha is, in fact, introducing aluminum-framed four-strokes to the motocross market next year. The announcement should come in early to mid-June.

[arel451]

I'd hate to say it, but I hope they delay it for one more year, because I'll be taking a bath on this one (04 450) when its time to renew.

[grayracer513]

Pro racers are quirky people. There could be any number of reasons. Mightt have been an early version, and a newer revision now exists, or it may have been 100% mental on his part, and had nothing at all to do with how it worked. Some of them are like that.

[MichiganMXer]

Yea I like my slippers on the right side of the bed.

?

I read where they may wait till 07 and introduce a brand new motor and the aluminum frame.

I dont think i can wait that long.

[Satch0922]

what kind of rules does the FIM have about production/pre-production bikes?

[DoctorRzed]

Correct me if I am wrong but the aluminum framed yz250 was seen in 2003 and did not come on the 2004's. So I wouldnt be surprised to see it on the 07 model.

[mnm567]

Anyone remember when the Cr's came out with the aluminumn frame in '97 and Jeremy Mcgrath ran the old steel frame because he liked the flex and feel of it better at the time. Could be the same situation.

[Fastest1]

Anyone remember when the Cr's came out with the aluminumn frame in '97 and Jeremy Mcgrath ran the old steel frame because he liked the flex and feel of it better at the time. Could be the same situation.

That is what I think also, aluminum is not necessarily a superior material. Steel that has been double butted, ridged, rifled etc. has excellent properties and weight. Italians specialize in tubings and they use it in Ducati's and other exotics with great results. Most quality bicycles still use steel and dont suffer any weight penalties. Yeah some build CF, AL and various materials but ride quality always suffers. Is the flex of our steel frames really hampering anyones riding abilities? I doubt it. It wont save any weight that couldnt be saved with steel and with steel cracking and repair are much easier. Aluminum doesnt like to flex, steel does.

[yz_for_me]

That is what I think also, aluminum is not necessarily a superior material. Steel that has been double butted, ridged, rifled etc. has excellent properties and weight. Italians specialize in tubings and they use it in Ducati's and other exotics with great results. Most quality bicycles still use steel and dont suffer any weight penalties. Yeah some build CF, AL and various materials but ride quality always suffers. Is the flex of our steel frames really hampering anyones riding abilities? I doubt it. It wont save any weight that couldnt be saved with steel and with steel cracking and repair are much easier. Aluminum doesnt like to flex, steel does.

You make a good point Fastest1. As an engineer, I've never understood why people think aluminum frames are superior. From a pure performance standpoint it's extremely hard to beat a steel frame.

You can't claim wait savings because it's proven the steel frame bikes are just as light as the aluminum ones. The YZ450 is within a couple pounds of the CRF and RMZ.

You can't claim aluminum frames feel better because the manufacturers go to great lengths to make the aluminum frames feel like steel frames. In developing the '05 YZ250 and 125, Yamaha went through many revisions to make the aluminum frame flex like the steel frame. Look how many years it took Honda to get their aluminum frame to have the right flex.

You can't claim aluminum frame bikes handle better. Look at the RM250 and '04 and older YZ's. They handle great and have steel frames.

The only reason I can see is marketing. Aluminum is new, sexy and sells better than "old" steel frames. Since selling bikes, not winning, is the real goal of the manufacturers, aluminum is the material of choice. JMO

[grayracer513]

I see it another way. The advantage of aluminum as a frame material is stiffness at a given weight. Since bicycles were brought up, I'll use the example of a Cannondale racing tandem I have left over from my bicycle racing phase. The frame uses very large diameter, thinwall aluminum tubing, and is stiff enough in spite of it's long wheelbase that two strong riders can stand up and hammer it up hills or in sprints. The frame only weighs 6.5 pounds. Anyone who has spent much time on a tandem will appreciate that.

In motorcycles, consider the fact that not one modern MX bike, and a decreasing number of street performance bikes use a steel swing arm. The reason is the same; a steel swing arm with an acceptable level of flex weighs too much.

Frame flex is bad. It results in the front and rear wheels moving around in and out of positions they aren't supposed to be in, the bike steering itself unpredictably in bumpy corners, and it's something that has been fought against by custom frame builders for as long as I can remember. It seems to me that the suspension is the component you would want to work with if the bike seemed too harsh, or "inflexible".

[mj2412]

I think it is a marketing and economic thing to change to aluminum frames. With a change to aluminum as material it is easier, cheaper to cut off a few pounds from the old frame than to construct a steel frame with the same advantages.

A few bicycle builder make steel bikes with the same weight than the aluminum bikes, but it takes a lot more engineering and so a lot more costs. Second the aluminum is hip now and like written above: sex sells.

At last the YZ500M frame of Stefan Everts wasn´t built by Yamaha, it was a construction from the Rinaldi Team (YRRD) because of the 500ccm rules at this time in the WC. When they changed to 450ccm an Yamaha built an 450 frame, suddenly they changed to the steel frame because of the costs and no disadvantage of the steel frame to the aluminum frame. They also changed the steel frame a little (mounts of the engine and steering angle) and built a new swing arm for Everts.

Martin

[Fastest1]

That Cannondale tandem you referred to is stiff due to the diameter of the tubing not the material. If you took a steel (thinwall) tubing of the same diameter you would get the stiffness you desire and it would be light. It would also be more durable in the long run. Pound for pound steel is still the strongest material. If they spent the time developing the steel as they have with aluminum the results would be the same if not better. Ever noticed how many bicycles (since you used to race) had broken frames after less than one season? They were all aluminum! If they were steel the only way you would break or crack one is to be hit by a car. Dragsters still use steel too.