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misdemeanors

Aluminum Frame vs. Steel Frame

61 posts in this topic

Hey guys,

This has probably been discussed in the past, however have any of you ever weighed your YZ 250 steel frames vs your YZ 250 Aluminum frames (considering bikes of approximate years)???? For instance, how about a 2004 YZ 250 with the steel frame vs a 2006 or later model YZ with the Ali frames? I have read that some bikes that have steel frames that the steel frames are anywhere from 1 to 5 pounds lighter than aluminum framed bikes.

Also, what are some advantages and disadvantes of each? I'm considering puchasing a late 2000 model YZ, and it seems like if you do some suspension adjustments or mods to the early 2000 model YZ's they will be just about as good as a late model YZ, and MAYBE even lighter...

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Well I don't know which frame is lighter but for sure the 05+ yz250's are lighter than the 04 model. It could be from other mods but I would like to think the alum. frame helped w/ the weight loss.

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mxjosh weighed his

http://www.thumpertalk.com/forum/showthread.php?t=576795&highlight=aluminum+weight

For anyone that doesn't want to click the link, mxjosh had a bare aluminum and a bare steel frame when doing the swap. He weight the alum at 18.4 lbs, and the steel at 24.2 lbs, meaning the aluminum was 5.8 lbs lighter.

Most publications were claiming the aluminum frame to save ~5 lbs when it was introduced.

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You'd think it would be more, but I suppose they need more actual aluminum on the frame to make it as strong as the steel one.

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Thats a huge amount for a motorcycle in one year....really, think about how long it took to lose 5 lbs before??? From 1996 to 2004. Then is drops 5 in one year.

In later years it dropped another lb from the front wheel , some from the swingarm, and another lb from the ti shock spring. Oddly enough, none of these extra weight measures showed a drop in tested weight??????

Advantages to aluminum? Weight, for sure. The alloy bike does feel light and is. Not that the steel frame felt heavy, but you get the idea. The aluminum also looks good forever with a tiny amount of care. No rust either.

I have yet to find any disadvantages. Dropping back to a 2000 would be a step back. Even though the engine is similar, the yz engine did not completely develop until 2001. It had a few smaller updates after that as well. The disadvantage to the 2001 and earlier is the old bodywork. The tank sat high and was not near as comfortable. This also did not do good things for handling as it made it more difficult to slide forward for a turn. The older bikes were also heavier.

This is all assuming you have not bought something already. If a person set aside a budget of 2000.00, there are many years of yz 250 to choose from. They really did get better each and every year and did not take any backwards steps. Well, that kickstart mechanism is a backwards step when it breaks, but otherwise.....

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I started out on an 05 wr450. I call her the "fat chick". She was heavy... and still is, but mainly when horizontal. Keep her upright and she's fun to ride.

I then got an 01 yz250 and it felt light as a feather. Weight is a non-issue. I am not sure of the actual weight though.

Just a month ago I upgraded to an 05. It feels a little lighter when loading it up, but a lot lighter when riding it. I am amazed at the difference. It feels like its a lot lighter than 4 or 5lbs.

If I could, I'd update the wr450 to an aluminum frame to get similar weight savings.

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As someone who just replaced his throttle stop I can tell you a disadvantage - the aluminum frame makes getting to parts of the carb a real b!tch. That said, I still think the advantages outweigh the disadvantages. Just don't ask me while I'm doing carb work.

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As someone who just replaced his throttle stop I can tell you a disadvantage - the aluminum frame makes getting to parts of the carb a real b!tch. That said, I still think the advantages outweigh the disadvantages. Just don't ask me while I'm doing carb work.

Remove rear subframe next time. Unfettered access granted. :banghead:

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The only real advantage to a steel frame is they handle better as 05 and up have a tendency to push the front occasionally. Now I have a 05 now but have had a 03,06 , and an 07 but all are gone but the 05 for now and theres not much diff in any of them to make the average rider any better or worse.

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I've been told the price of steel went through the roof and the switch to AL was to keep the profit margins in-check. I've ridden multiple late model steel-framed YZ's and the only difference I could tell between them was the suspension didn't feel the same as my 06'. I've heard quite a few others say they prefer the old steel frame for the flex properties.

The geometry from the 04' (steel) to current (AL) is identical, I believe. The 5# weight savings was just the cherry on top.

I do like not dealing with fading paint, but other than that I would be more than happy with steel.

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As someone who just replaced his throttle stop I can tell you a disadvantage - the aluminum frame makes getting to parts of the carb a real b!tch. That said, I still think the advantages outweigh the disadvantages. Just don't ask me while I'm doing carb work.

I think this guy is referring to a 450 not the 250 2stroke and he is absolutely correct. The head stays prevent rotating the carb, atleast on the 06 model. The rear screw to the top plate to get to the slide was also hard to get to and the sub frame had nothing to do with either of these things.......

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Ok all great info. One of the reasons I brought this up was because of an article that I read on twostrokemotocross.com. Now it doesn't say much about weight, but I think the guy makes a good arguement for steel frames. If you scroll about half-way down the article to the "Nuts and Bolts" header, he talks about some of the advantages and dis-advantages. I understand that he is talking about a Maico, but I think his discussion on frames is pretty good and probably can be used as information on all frames. Thanks again for all the replies.

http://twostrokemotocross.com/2009/12/2004-maico-500-long-term-test-report-%e2%80%93-part-2/

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Yep, mine was on a 450 but my comment was in general. I've had the 250, 450, and WR250 and the aluminum frame always gets in my way at one time or another.

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Ok all great info. One of the reasons I brought this up was because of an article that I read on twostrokemotocross.com. Now it doesn't say much about weight, but I think the guy makes a good arguement for steel frames. If you scroll about half-way down the article to the "Nuts and Bolts" header, he talks about some of the advantages and dis-advantages. I understand that he is talking about a Maico, but I think his discussion on frames is pretty good and probably can be used as information on all frames. Thanks again for all the replies.

http://twostrokemotocross.com/2009/12/2004-maico-500-long-term-test-report-%e2%80%93-part-2/

That is a good article, and probably truth based, at least. Some things dont make a lot of sense. I dont think many who have welded on the Japanese steel frames would call the material "High Quality". Plus, the Japanese found enough steel to make frames for many of their low end street and dirt bikes, which they sell a ton of. That woudl have been the place to use aluminum if material shortages were the issue. Also, it it were about a steel shortage, wouldn't there be an Aluminum Prius by now?

In the case of the yz 250, the frame lost over 5lbs when it switched material. Thats a huge amount of weight to lose on a part that works very similarly to the one it replaced.

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In the case of the yz 250, the frame lost over 5lbs when it switched material. Thats a huge amount of weight to lose on a part that works very similarly to the one it replaced.

Sounds like a great way for the KTM 250SX to have an even greater weight advantage.

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Sounds like a great way for the KTM 250SX to have an even greater weight advantage.

It would, for sure. If lit lost another 5 lbs, it would weigh 205. Unreal for a 250. I think sometimes its easy to look at a pro-con list and pick out only the statements which support and individuals argument, and I believe that happened in that article.

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Yeah I agree, I noticed that he did not say anything in that article about weight advantages. He did make some good arguements about steel framed bikes, but didn't really delve into the issue of the advantages to Aluminum. I have ridden both and in my opinion you can tell a difference. And like RCannon said, 5 lbs is huge in just one year of bikes. That is something we all could probably feel if we rode those bikes back to back. I think Ali frames will be around for a while, and can't imagine the MFG'rs going back to steel ones.

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It sounds as if the ali frame is substantially lighter, but is the complete package? I know it's the manufacturers literature on weight, but my manual says the 03' wet weight "oil and full fuel" is 230.4 lbs. The 2010 literature says wet weight is 229 lbs. I'm wondering what happened to all the weight savings? Ali frame, lighter swingarm, ali handlebar , titanium spring, titanium footpegs, thinner fork tubes, lightened calipers, fork protectors, axles, wheel collars, axle brackets, wave rotors, and some stuff I probably forgot over the last 7 years has amounted to a net of 1.4 lbs??

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