Half frame zx10?> sketchy no?

[Klondike1020]

I am thinking about getting this bike because of the half frame. It is so cool but also sketchy.

is this sketchier or less sketchy than a salvage title

It comes with a new title for the custom built frame



http://stunterx.com/s/

WTF

[Alex]

Originally Posted by Klondike1020

is this sketchier or less sketchy than a salvage title

I'll take sketchier for $1000, Alex.

[Klondike1020]

Originally Posted by Alex

I'll take sketchier for $1000, Alex.

I have been reading forum reviews about these half frames and the people who get them love them.

But it is super sketchy.

I think it would make a very cool custom bike though. No one will have anything like it. This bike came from Stunterx shop. It was the first zx10 they have done and they havnt sold any half frames for the zx10 yet.

It was completed a couple months ago and they used it to set up their frame building jigs.

Here is a pic of the half frame of an F4i

I think that is sketchy but an awesome business plan

Make frames with new vins- swap totaled bikes onto the frames and sell said bikes as custom!!!

[cuong-nutz]

I'd rock it.

[nickjpass]

Normally I see trellis(?) frames like these on stunt bikes

This is on my to do list for my 6r since I tlove looking at the engine.

[choneofakind]

Until I see an FEA for each frame and can compare them under the same forces for multiple scenarios and you can prove to me that the custom frame is good for the job at hand, I'm putting this one in the 'sketchy enough to not waste money on' category.

It looks pretty badass though.

[ninjamunky85]

Originally Posted by choneofakind

Until I see an FEA for each frame and can compare them under the same forces for multiple scenarios and you can prove to me that the custom frame is good for the job at hand, I'm putting this one in the 'sketchy enough to not waste money on' category.

It looks pretty badass though.

If their frames are getting real world testing from stunters then I probably wouldn't dismiss their strength so quickly.

[csmith12]

Only if you got "extracurricular income". There was a gent at the track with a custom frame just a few weeks ago. He needed some tweaking here and there that cut into his riding time. So be prepared if you go that route.

[nickjpass]

Not sure what brand this but its a 03/04 6r o believe, with an aftermarket frame.

Link to original page on YouTube.

[choneofakind]

Originally Posted by ninjamunky85

If their frames are getting real world testing from stunters then I probably wouldn't dismiss their strength so quickly.

This is sort of a case of "yes, but..."

It's not all about just strength. It's about how it flexes. It's about how far is can deflect before the bend becomes permanent. It's about how much the frame dampens and/or transmits while leaned in addition to how rigid it is both upright and while leaned. Don't forget that stunners and racers put their frames through very different stresses, ie bumps and vibrations while leaned over vs frequent big impacts from landing wheelies and stoppies.

This is the same difference between a farmer welding up a broken tractor part vs an engineering firm designing a new version of the same part. Sure both 'work' but one is pure luck and might not be comparable to what it replaced.

[ninjamunky85]

Originally Posted by choneofakind

This is sort of a case of "yes, but..."

Sure both 'work' but one is pure luck and might not be comparable to what it replaced.

That frame doesn't exactly look like it was designed by a farmer, unless it was a farmer that was good with his trig. Also you'd be surprised how far that so called "luck" gets you.

Also this frame is made out of steel vs aluminum. Obviously steel is much more resistant to stress fractures from vibration than aluminum. Designed and built properly it should be a solid frame.

[choneofakind]

Dude. It's chassis design. It's not that simple.

Steel flexes. Yes it's more resistant to stress fractures because of how steel fatigues vs aluminum. But you're not getting the point. Liter bikes are designed very carefuly to give a ride that's the right level of compliant and the right level of stiff under very specific conditions that the engineers have deemed important. Remember that liter bikes are homologated to be used in racing, so frames are built with the intent of being race worthy and giving the feedback that the racers want.

Vehicle chassis design is not as simple as material choice and fabrication. Will it work? Sure. Will it be ideal for the given vehicle design and satisfy the needs of that homologated bike? Not necessarily. You realize there are entire programs of graduate study for engineers based on vehicle chassis dynamics right? It takes years of study to be competent to design a chassis, not just building it.

[choneofakind]

Also, That's such a major modification to the vehicle that they better have some well worded liability release forms to go along with each sale.

[Alex]

It's a small picture, so hard to tell details. But no matter how strong that trellis part is, the part that would scare me first is that attachment from the steel tubing to the back half of the aluminum frame. The whole swingarm and rear of the engine is attached there, while the front load is now carried by the new half frame. However strong that attachment between the two halves, could be the difference while leaned over at speed and hitting an unexpected bump. I think a stunt show in a parking lot would be a perfect way to test out funky chassis designs after the first frame was destroyed. I think riding one on the street or track at speed afterwards is a higher risk than I'd be willing to chance.

[ninjamunky85]

Originally Posted by choneofakind

Dude. It's chassis design. It's not that simple.

Never said it was ideal, or even better than stock. But obviously people are riding these bikes around, sooo...

[choneofakind]

But you're missing the point. Until I see data from their design work, I will consider it sketchy. Why?

Because 1) we don't know hw reliable it is. We don't know what factors of safety they used or how it compares to stock in that aspect. We don't know what forces or impacts they were intending to design for.

2) we don't know how much work they put into keeping the character of the bike the same, ie, how much vibration damping and flex this new frame has in comparison to stock.

Ever ridden a chrome-moly bicycle and compared to an aluminum bicycle and then compared to a carbon bicycle back to back to back? The chromy bike is flexy and willowy, yet very comfortable compared to the aluminum, but it could go either way compared to the carbon. Is it possible that all three bicycles have the same dimensions? yes. Will they all work for making you sweat and not die from catastrophic frame failure and get you transportation/exercise? likely. But those three bicycles will all feel completely different to the rider, and it's obvious to even the most casual rider that something feels different about each bike. Maybe they aren't as anal-retentive about picking out each individual little aspect that makes each frame different, but they'll be able to hop off and say 'wow, that one felt really uncomfortable" or "this one feels softer and does go as fast when I stand up and crank".

The company that makes these custom half frames, while they're probably safe due to real world testing, likely changed the whole character of how that chassis responds and feels.

3) I frankly just don't trust a gigantic modification like this as anything other than a last resort. That's a huge change that takes your bike from a production vehicle with a history and a safety record to a motorcycle that is essentially a kit vehicle, built by an aftermarket company.

There's just a lot to design around when making a vehicle, and until I see what they did, I would not trust it. Designing a chassis to behave with a certain character and building a chassis that will support a motor and mate with the rear subframe are two very different things. Sure, both work, but they are NOT interchangeable solutions to the problem.

EDIT: sorry for the rant(s) here, but as you can tell, I strongly dislike when people tell me that thing x was built and works, so clearly it's good enough. I dislike being told that 'it works, so it's good enough'. Farmers fix tractors and fences to be 'good enough'.

[Soujyu]

That almost reminds me of the idiot cutting a hole in his frame on his Ninja to lose some weight.

If you want to get a trellis frame, get a Ducati.

[Xtina]

Would not buy. Looks like a death trap. you don't mess with frames. Whose to say this was built correctly?

[alex.s]

Originally Posted by choneofakind

Until I see an FEA for each frame and can compare them under the same forces for multiple scenarios and you can prove to me that the custom frame is good for the job at hand, I'm putting this one in the 'sketchy enough to not waste money on' category.

It looks pretty badass though.

ok, i'll do it.

[Finesse]

Supah sketchhhh