WTF???
Calling frame designers (BCD zedro DW etc) Cast Frame?
- Thread starter klunky
- Start date
So other than being different, it sounds like it will be heavier, weaker, perhaps more expensive. As compared to good old welded tubes what are the potential advantages?
It could be cheaper is you built a gazzilion of them.
Well, one of the parts that needs to stand up to insane temperatures and resist fatique and wear are the turbine blades, and they are cast as single crystal alloys. Insanely strong, much stronger than a forged part. It all depends on the manufacturing process, since there are exotic things out there such as turbine blades...but that doesn't make it a good idea for everyone. Still, ironic that one of the most critical parts is cast, not forged.
(oops, already covered I see).
there is alot to read. got through 3/4 the first page.
what i'm getting from all this is that casting isn't as strong as forging. and dirt bikes use casting.
does this mean that the motorcycle industry is going to be taking from the bicycle frame industry? making motorcycle frames using forgeing techniques?
what i'm getting from all this is that casting isn't as strong as forging. and dirt bikes use casting.
does this mean that the motorcycle industry is going to be taking from the bicycle frame industry? making motorcycle frames using forgeing techniques?
strong enough meaning much heavier. 747s are built like tanks compared to what they're doing now, where purchases are made based on efficiency.
production dirt bikes are being made for cheaper production costs, not because of lack of know-how. I'm not sure if the race frames are different (i know most of the components are), but the weight/performance penalty isnt as big as it is for bikes, so less push for expensive refinements.
Well, it's not quite as big a deal to save a few ounces here and there on a motorcycle, since the power source is bigger, so a thicker cast piece will suffice most of the time to obtain the necessary strength. It might be different for the uber-race bikes for the big budget teams, but for the majority of bikes, you've got a big engine so a less refined but heavier piece for the same strength will work.
edit: I see Zedro said almost the exact same thing while I had my reply window up and got pulled away, so... I'm with stupid
You are exactly right on why MX bikes use castings. With CNC machining of billet, a bunch of material is tossed in the scrap bin. Not cheap especially when you add in the $100/hr+ cost of running the mill. Forging tools can be $500k+.
Off topic:
MX race bikes in the US are production frames. They are required to be homologated with 400 bikes sold to the general public. No frame modifications can be done. Even the head angle needs to be stock. The AMA actually imponded several frames last year to check them on a CMM.
Japan is entirely different. They run exotic stuff all the time. Thats where the mags get the "spy" photos of next years bikes.
Suspension is on a claim rule. In the "lites" class, any competitor can buy the suspension for a set price ($3500 I think). If you don't sell it, your done for a year.
In the amatuer AMA races, whole bikes can be claimed for 120% of retail. I'd like to try it sometime with some of the guys I race with since they have $10K+ into the engine with Pro Circuit. I have seen a 50cc claimed before. Parrent's were pissed.
Neither, Solar Turbines.
Before long cast turbine blades will be replaced with ceramic blades.
Definitely. You can make some pretty amazing parts with the investment casting process. When I was working ofr the govt. we built some 6061 investment cast parts with hollow sections and 1.5mm wall thicknesses. Really pushing the limits of the process but the parts were amazing. That bike looks like a pattern mold to me though, at least based on how I would go about building tooling, but every designer thinks a little differently, so who knows. Makes me want to cast some random stuff! (like a new wood stove)
The 2007 KTM motocross bikes use a 1 piece cast swingarm that appears to be hollow! The 2007 KTM 250 SX is 10 lbs lighter than a YZ is which is the next lightest.(210 lbs) It is illegal to race in the Pro field because it is under the weight limit. interesting stuff.
What the hell does that mean? I bet thats some weird Dave talk for nuclear missile made of aluminum foil and cast cheetos or something.dw said:
Freak.
No seriously I was checking out this awesome old wood potbelly stove at my frineds house on Wednesday. Somebody put a lot of thought into making the thing, it was awesome. All cast iron and brass. It made me want to build one of my own.
DW, Speaking of casting or forging, what do you think of a Magnesium back plate or something like that to bring the weight down on the e-13 chain guides even more? i am not an engineer but who can forge or cast Magnesium? It would be cool if you could do it for a back plate/boomerang maybe???
Ooooohh! And if you managed to destroy it, you could light it on fire!
if you chage the geometry you have to almost completely re make the bike in the inventor CAD or simmular enjineering program and that can take a long time. my sense is that they figure out the geometry before designing it in CAD. that way they can fit the frame to the geometry that they want
mmm you could change the angles a small amount by, for example boring the Headtube bearing seats' axis differently, in the same way you could bore the bb axis slightly differently.
You'd need to provide enough room in the blank casting though. not ideal.
Whoops
You'd need to provide enough room in the blank casting though. not ideal.
Whoops
Well like it was said earlier Cast has been done before.
Here is my mates (now mine) Kirk.
Personally I wonder if with correct engineering, proper stress analyisis etc a cast frame (especially if investment etc) could be a good thing.
Material where you need it, in the grade you need it in, we could even see magnesium alloys coming back in
What concerns me is there is no gearbox in there
Here is my mates (now mine) Kirk.
Personally I wonder if with correct engineering, proper stress analyisis etc a cast frame (especially if investment etc) could be a good thing.
Material where you need it, in the grade you need it in, we could even see magnesium alloys coming back in
What concerns me is there is no gearbox in there
Cool idea.
In terms of mass production its the way to go. I can't see cutting, mitering and welding in jig by hand being cheaper when the volumes get large. Maybe they are aiming at cheap entry level DH rig. I have no doubt the thing won't be super light, but i don't think that is the objective.
In terms of mass production its the way to go. I can't see cutting, mitering and welding in jig by hand being cheaper when the volumes get large. Maybe they are aiming at cheap entry level DH rig. I have no doubt the thing won't be super light, but i don't think that is the objective.
I feel that getting a 100% cast frame to be as strong for the weight is next to impossible, if you dont have a means to make hollow tubing. Much of the stiffness and strength in a bike frame comes from bending and compression, both of which hollow tubing performs much better than I-beam, or even solid sections. Cast sections, on the other hand, sound like a great idea to me.
hells no, CAD (especially 3D top down feature based modelling like Solidworks et al) makes the design process faster and easier (thats why we use it). Making a change like headtube angle takes about 5 seconds.
and if you didnt notice, thats a CAD rendering, not a real frame
Hmm. 
I'm not going to open my mouth just yet, but from what I've learnt through manufacturing process classes and metalurgy, casting is a scary proposition for something as light as a frame. We'll see though, perhaps new methods are being developed that can eliminate some of the problems. One big question though: Die cast or conventional?
I'm not going to open my mouth just yet, but from what I've learnt through manufacturing process classes and metalurgy, casting is a scary proposition for something as light as a frame. We'll see though, perhaps new methods are being developed that can eliminate some of the problems. One big question though: Die cast or conventional?
Looks pretty pro to me, the only thing that I'd be worried about is where the toptube/seattube meets the bb area - if that's a pivot mount, not just a casting boss (but i guess the short strut where the main pivot is would take most of the loading).
Whoops
edit - my bad. Just looked at the renderings and its a mount for the chainguide top wheel.
Whoops
edit - my bad. Just looked at the renderings and its a mount for the chainguide top wheel.
I bet some of those edges on the top tube and seat mast would cut the crap out of your knees when knee steering. Theres probably a few that could bite at your ankles too.
that frame is kirked out.
well i guess they have already got the tooling done...
I think that frame looks wicked.
Don't think I'd buy one. But I like the look.
Definitely would want some hardcore fork bumpers to keep from denting your upper stanchions.
Its hard to tell how thick they are from the photo, but those ISCG tabs look like they would be the first thing to fail IMO.
Don't think I'd buy one. But I like the look.
Definitely would want some hardcore fork bumpers to keep from denting your upper stanchions.
Its hard to tell how thick they are from the photo, but those ISCG tabs look like they would be the first thing to fail IMO.
we have a weight for this thing yet?
is that a plastic proto? doesn't look like an alloy to me.
looks sweet to me. just wondering about the weight. kinda looks like minaars g-cross bike..i wish.
looks sweet to me. just wondering about the weight. kinda looks like minaars g-cross bike..i wish.
looks like sand blasted alu to me, but that is pure e-speculation
Dunno if it's sand blasting - maybe, but could also be the normal finish if it was green-sand cast for a proto.
well shot-peening would be a very good idea here; it would give it that look
14 is bad but not that bad. is that with shock?
let me know if you need test riders. i would be happy to break one of those things for you.