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my "new" boxxer is kaputt

Kanye West

220# bag of hacktastic
Aug 31, 2006
3,740
470
Yeah pretty much. Don't think the words "six sigma" even cross their minds. Nowhere near the production numbers.
 

Yeti

Monkey
May 17, 2005
877
0
yeti cave@the beach
Jesus...
Call SRAM, get someone's email in the tech. dept., and send them the hi-res pics - they will definitely want to see this.

EDIT: Have the serial number from your fork handy when you contact them.
Was just on the phone with SRAM-europe. Explained them what happened and asked them if they wanted some high-def pictures of the fracture. They weren't interested and told me just to go through my lbs. Anyway bikeshops are closed on mondays here in Zürich so I'll have to wait until tomorrow.
 

istratetm

Chimp
Jan 19, 2009
78
0
It has "bubbles" that don't seem to have a corresponding filling counterpart on the other side of the fracture and the magnesium seems a bit to corny and therefore brittle. Any materials engineer out there thinks the same?
Here it is:
I'm sorry that happend to you. As a materials engineer who works in a foundry, i can tell you that is for sure a defective product from the start. The casting was defective and it should be coverd by warranty.
Casting the lowers of a fork out of Mg is a fairly difficult thing. That is high precision casting and the technology has to be spot.
Those bubbles that you see are caused by the gas that occurs during the casting process, that was trapped inside the part. The mold has to have some bleeding ports placed in the areas wich are prone to develop bubbles.
You should be covered by warranty!
 

jonKranked

Detective Dookie
Nov 10, 2005
85,558
24,181
media blackout
Yeah pretty much. Don't think the words "six sigma" even cross their minds. Nowhere near the production numbers.
You can still implement 6σ on smaller production runs, but the ROI won't be there to justify it, even though a single reject represents a larger percentage of the overall production quantity.
 

wood booger

Monkey
Jul 16, 2008
668
72
the land of cheap beer
Yeah, bad fork.

Yeah, crappy quality/process control.

Six Sigma? bahahahah, you should see the place where these are made. Are lowers in one piece w/ no visible holes? Sweet, ship it! The biggest question is how many they can stuff in a box.

Fox had a similar problem w/ 32 lowers snapping at the dropout 4-5 years back. Look at the DO area of a 32mm Fox now, super beefcake. Casting Mag can be tricky and bike companies can't/won't spend the time and money on inspection and process control that say a moto company does. It is not economical. They basically overdesign and throw a ton of material at problem spots. It looks like RS didn't quite put enough in the arch area.

I just hope no one gets really hurt on one of these.
 

Spokompton

Monkey
May 15, 2005
321
0
Spokane WA
Yeah, bad fork.

Yeah, crappy quality/process control.

Six Sigma? bahahahah, you should see the place where these are made. Are lowers in one piece w/ no visible holes? Sweet, ship it! The biggest question is how many they can stuff in a box.

Fox had a similar problem w/ 32 lowers snapping at the dropout 4-5 years back. Look at the DO area of a 32mm Fox now, super beefcake. Casting Mag can be tricky and bike companies can't/won't spend the time and money on inspection and process control that say a moto company does. It is not economical. They basically overdesign and throw a ton of material at problem spots. It looks like RS didn't quite put enough in the arch area.

I just hope no one gets really hurt on one of these.
Word. Engineers in CATIA can't ever assume that the real world is going to be even slightly perfect. Must be why so many of the Mag Ellsworth rockers were snapping. Looked great in a structural analysis program, pure fail-boat in real world manufacturing and riding.

Must also be why products built within 1 inch of death, for weight savings, must cost A LOT if you want one without defects.
 

ohio

The Fresno Kid
Nov 26, 2001
6,649
23
SF, CA
bike companies can't/won't spend the time and money on inspection and process control that say a moto company does. It is not economical. They basically overdesign and throw a ton of material at problem spots.
You can't think this is true. The difference in weights between MTB and Moto components is an order of magnitude, while performance and strength is actually pretty close. When 40lbs total weight is considered heavy, you CANNOT just throw a ton of material at problem spots.

Mountain bikes are far more refined for weight and use much more expensive materials than moto bikes. Where they fail is that bike companies (and consumers) are far more tolerant of first run defects as a tool for QA/QC.
 

Kanye West

220# bag of hacktastic
Aug 31, 2006
3,740
470
The difference in weights between MTB and Moto components is an order of magnitude, while performance and strength is actually pretty close.
No, no and no.

An average DH fork weighs, what, 6-8# with the crowns and axle? A single fork leg on a full size dirt bike weighs around 10-11# each, so with the triple clamps and axle you're looking at around 26#. Hardly an order of magnitude.

The performance of the BEST mountain bike suspension is still so far behind the abilities of decent motorcycle suspension that it isn't even funny.

Strength is pretty close? I don't even need to justify that one being far off base. If this kind of crap happened to an OEM motorcycle fork, the products would most likely be recalled and/or someone would get sued. The abuse that a MX or Desert race ready bike and components take is truly orders of magnitude different than that which a DH bike or component sees.
 

Jonny5

Monkey
Feb 13, 2007
502
0
Saw another snapped brake arch on the weekend. Same spot- near the zip tie loops, same deal- just a small uneven landing. Looks like this is going to be an issue.Do'h