New potential products for 510's and Datsun from Mattndew76

[Mattndew76]

It could be done. Is it what people want?

[toylet]

I have the R200 set up for my 510.. just don't have the mustache bar yet. So I would be interested.

[Mattndew76]

If you have a good technical drawing or a part I can't get the needed geometry from. These would be a part I can produce. R160, R180, and R200.



Matt D.

[StrutlessWonder]

It has already been done by Eric Straw (for R160/R180):
http://www.the510realm.com/viewtopic.ph ... 10#p153883
I have a DXF file, but Eric has the final version. Maybe he and Matt can work out a deal...
There was little interest at the time for $295 plus bushings, but I got mine

[Mattndew76]

I bought a little red roller chassis from Mr. Straw once.

If Eric is on here have him send a PM or I could.

Does the R200 need different geometry? Does it sit further back than the R180?

[toylet]

If I had the r160 in my 510, I would just leave the stock diff bar. Which probably explains the little interest, but all the guys that upgrade to R200 will need to change the diff bar for it to fit properly. So there might be more demand.

[Mattndew76]

Seems the R200 would need its own mustache deigned.

Do we have links to people's mustache mods to accommodate the R200?

Matt D.

[JordanTr]

I just bought a Datsport R200 mount since Mario's sick billet one was a lil (lot) out of the student budget.

I know some of Mario's steel R200 bars have holes for both the Z31 2 bolt spacing as well as the R32/33 2 bolt spacing which opens it up for high cap diff covers (stock or otherwise) from other chassis' such as J30, S14, or R32/33. That may be a feature to think about although it may be a bad idea in aluminum due to crack tendencies.

Fire e510 a message.

[Mattndew76]

I have been trying to find some threads that have shown a failure or cracking in an aluminum support bar (mustache). I want to learn from this, but I can only find stuff that has third to fourth party type hyperbole with no solid factual images. Very frustrating...

Is this an urban legend?

[McWicked]

Is this an urban legend?

Most probably.

Steel is far more ductile than aluminum and has a practically infinite fatigue life when kept within the realms of elastic deformation. Or in street speak: unless you bend it, it'll last forever. Aluminum, on the other hand, will eventually develop fractures after a number of stress cycles. It's this fact that scares many backyard engineers away from aluminum. But a properly designed part (using an appropriate alloy) will have no problem providing an adequate lifespan.

-McWicked

[Mattndew76]

Throughout the 20 years of metal manufacturing I have come across 000,000,000 fatigue failures in drawn non ferrous material such as 6061. With cast aluminum I have seen many failures due to imperfect cast environments, gas pockets, and cooling fractures.

"Or in street speak: unless you bend it, it'll last forever. Aluminum, on the other hand, will eventually develop fractures after a number of stress cycles. It's this fact that scares many backyard engineers away from aluminum. But a properly designed part (using an appropriate alloy) will have no problem providing an adequate lifespan. "

^^^^This is has been my conclusion for many opinionated debates. A perpetuated half truth of half assed researched facts blown up into a full on nuclear failure.

If and I mean a BIG if these arm chair engineers can produce this failure. Please show me the cyclic data and design used. Because I am guessing that if the Legend would have some sliver of real truth. My guess would be its a design based failure and not material cause.

[McWicked]

...I have come across 000,000,000 fatigue failures in drawn non ferrous material such as 6061.

Oh I don't know... I've seen a ton of failures in 6061 aluminum. But then again it's what I do for a living. As in I perform environmental, proof-loading, acoustic/modal/vibe and structural testing in the aerospace industry. The destructive testing being a personal favorite. So yeah, I'm an actual engineer. Not the "I'm not an engineer, but I play one on the internet" variety.

But anyway, in my line of work when it comes to completely unexpected failures in any of the grades of drawn 6xxx, the vast majority have been manufacturing and welding related. Not materials related. Cast parts are an entirely different animal, as we both know.

If and I mean a BIG if these arm chair engineers can produce this failure. Please show me the cyclic data and design used. Because I am guessing that if the Legend would have some sliver of real truth. My guess would be its a design based failure and not material cause.

Yeah, I seriously doubt anyone is going to float that data out for you. Even if they hit up Wikipedia or the Google machine for the answer, they'd most likely end up regurgitating some data from the wrong sort of test, conducted for a completely unrelated field.

I think aluminum gets it bad rap because it won't suffer a fool like steel will.
-McWicked

[toylet]

I think the diff cover would crack before the bar does.

[okayfine]

But anyway, in my line of work when it comes to completely unexpected failures in any of the grades of drawn 6xxx, the vast majority have been manufacturing and welding related. Not materials related.

Thoughts on this failure?

IMG_2805.jpg (182.83 KiB) Viewed 3669 times

Stoker's bottom bracket of a mountain tandem. 6061, heat treated. ~3 years of use, no abuse but plenty of 22/34 gearing climbs up stuff; most people never break one but we're not the first. The removed powdercoat is from dirt getting between the BB shell and the rear suspension.

Another view.

ECdM BB Crack - JS.jpg (164.91 KiB) Viewed 3668 times

Sanded part here was me determining the shell was cracked and not just the powdercoat.

We've since stepped up to a steel version of that frame and expect to never have an issue again.

[Mattndew76]

Julian I think the failure in the frame you show has a lot to do with design. Even in drawn material a square abutment is far weaker than that of a radial abutment. I would go so far as to say that if that portion pictured had a radius transition like the portion to the right in the photo the cracking would not be occurring.

Mr.Wicked what says you?