Does this look like a crack? Momsen Al129 -2018 model

[Shebeen]

On 9/23/2021 at 4:44 PM, ChrisF said:

 

For my sins I "was volunteered" to mentor our young engineers ....  

 

We appoint a guy with about 4 years post qualification experience, and put him to work on a nice entry level project.  Not long before he brings me his "design" ....  I do the typical quick rule of thumb cross check ..... OOOOOO cr@p, the system is UNDER designed by a factor of about x20 !!!

 

Breeeeath .... a mentor should assist and guide, and all that ....

 

So we go back to basics and I take him through the steps ..... NOPE.  He assures me he KNOWS this stuff, and have been doing it for "years", and he TRUSTS his answers !!!   Then he tells me he used "the design software, so the answer MUST be right...."

 

 

 

Reminds me of my days as a student with Dr Less Rencontre.  He did his doctorate in designing stress analysis software.  MAN, was he passionate about getting a "feel" for the reality, and NOT blindly trusting the computer output !!!

 

 

 

or like the time a service provider to the NHS used .xls format for their CSV to track the government's covid testing

ran out at 60 000 rows. the .xlsx could do a billion or something, and took a while for someone to notice

much more eloquentlyu explained in this brilliant podcast

https://timharford.com/2021/05/cautionary-tales-wrong-tools-cost-lives/

[Sprockets]

On 9/22/2021 at 11:19 PM, Mountain Bru said:

As long as you're not an industrial ""engineer"".... 

I realize industrials are the oompa loompas of the engineering world. I suppose they do have their place somewhere.

Why are you against it? New comers with big heads too big for themselves? or just doesnt follow conventional ways? ????‍♂️

Just expanding my horizons

[Trashy]

3 hours ago, dasilvarsa said:

The Damage Was due to an Accident where the Saddle Was Totally Destroyed.

Welding was done by a Professional Engineer.

4 Years Later Some Extreme Riding and Still Holding Up.

The damage that happened above is in one of the few places on a bike frame that is very minimally stressed by typical riding forces, if the seatpost is sufficiently inserted into the seat tube. Additionally, it is strongly gusseted, making the entire joint stronger than it otherwise would be.

I can guarantee you that the aluminium surrounding the repair is softer than it should be, and any hardness test would confirm this.

The fact it has worked in your particular case does not make it good practice or good engineering.

Edited September 29, 2021 by Trashy
Grammar

[Mook]

50 minutes ago, Trashy said:

The damage that happened above is in one of the few places on a bike frame that is very minimally stressed by typical riding forces, if the seatpost is sufficiently inserted into the seat tube. Additionally, it is strongly gusseted, making the entire joint stronger than it otherwise would be.

I can guarantee you that the aluminium surrounding the repair is softer than it should be, and any hardness test would confirm this.

The fact it has worked in your particular case does not make it good practice or good engineering.

I agree with Trashy ????

Alloy frames are heat treated after having been welded when built. The entire frame, welds included, are brought to a even temperature before cooled down. When new welds are done, the metal around the weld "softens" and usually crack around the new weld due to the new joint being stronger than the adjacent alloy. Aluminium frames have been repaired with great success, BUT it remains a risky process.

I had a similar problem as OP, and was told by a reputable brand agent that it was a simple paint crack ........................ 3 months later it failed spectacularly AND the warrantee expired between being inspected and failure. SO, the manufacturer got themselves out of a factory replacement by arguing that it was a paint crack and left me high and dry with the broken alloy frame.

Paint cracks at/near stress junctions ........................ NAH ????

[Mook]

3 minutes ago, Mook said:

I agree with Trashy ????

Alloy frames are heat treated after having been welded when built. The entire frame, welds included, are brought to a even temperature before cooled down. When new welds are done, the metal around the weld "softens" and usually crack around the new weld due to the new joint being stronger than the adjacent alloy. Aluminium frames have been repaired with great success, BUT it remains a risky process.

I had a similar problem as OP, and was told by a reputable brand agent that it was a simple paint crack ........................ 3 months later it failed spectacularly AND the warrantee expired between being inspected and failure. SO, the manufacturer got themselves out of a factory replacement by arguing that it was a paint crack and left me high and dry with the broken alloy frame.

Paint cracks at/near stress junctions ........................ NAH ????

 

[Hairy]

4 minutes ago, Mook said:

 

Is that a Giant frame or a spech frame?

[Hairy]

4 minutes ago, Mook said:

 

How did the manufacturer inspect the frame?

Just with pics or a physical inspection .... if just pics you could argue they did not exercise due diligence with their initial inspection?

[Mook]

25 minutes ago, Hairy said:

How did the manufacturer inspect the frame?

Just with pics or a physical inspection .... if just pics you could argue they did not exercise due diligence with their initial inspection?

Spez Epic Comp frame

The frame was stripped and sent to Spez in Stellenbosch ......................... WELL, according to the bike shop. I got the bike back in 1000 pieces since I refused to pay R1.5k to have it reassembled after THEY stripped it to have it inspected ????. Bike shop in the Cape Town southern burb's that used to sell Spez before the Concept stores initiative took off in 2015/2016.

I was not impressed, BUT I suppose that's the way the cookie falls apart hey ????

[Mojoman]

4 hours ago, Mook said:

Spez Epic Comp frame

The frame was stripped and sent to Spez in Stellenbosch ......................... WELL, according to the bike shop. I got the bike back in 1000 pieces since I refused to pay R1.5k to have it reassembled after THEY stripped it to have it inspected ????. Bike shop in the Cape Town southern burb's that used to sell Spez before the Concept stores initiative took off in 2015/2016.

I was not impressed, BUT I suppose that's the way the cookie falls apart hey ????

Lol...I was considering buying a Specialised as they have lifetime warranty and transferable warranty....Maybe I will just roll with a Raleigh and hope for the best.......????

[MORNE]

16 hours ago, RustyHWR said:

Maybe i was just lucky, but TWT / Momsen  refunded me in full (purchased price) for a Momsen GP300. Had a problem with the hanger on the frame that could not be fixed. Replaced the hanger a few times with no luck.

 

You were, took me three shipments, lots of proof, phone calls, to and fro just to GET a hanger, and axles, and headset…that were supposed to be in the box. Even funnier was I personally called and asked un double checked on here via pm too if everything was included, still got here unusable haha. 

Were you really that lucky though? Sure you got you money back but these places think they do you a favour shipping stuff out to you for free and overnight a few times after they got it wrong but they are more lucky that I don't invoice them for my time they wasted imo. 

Edited September 30, 2021 by MORNE

[Mook]

8 hours ago, Mojoman said:

Lol...I was considering buying a Specialised as they have lifetime warranty and transferable warranty....Maybe I will just roll with a Raleigh and hope for the best.......????

Hi Mojoman,

Ja right................................... LIMITED LIFETIME ????

In defense of Spez, you will find the exact same fine print in most other big name brand warrantees, ie. Giant, Scott, etc. The definition of "LIFETIME" is 5 years, based on the expected lifetime of a frame - not the rider. Yes, only 5 years ????

This weak spot is actually a very common "weak spot" on most dual suss frames. I have personally seen Scotts and Giants break in the exact same spot on the drive side chain stay near the brace(roughly 15-25mm behind the main pivot). The carbon frames are more reliable, BUT not infallible. In my efforts to source a new alloy rear triangle, I managed to get my hands on a new carbon chain stay which fitted perfectly, barring a few slight mods ito a longer pivot bolt due to the carbon unit being bulkier than the alluminium. Spez could not supply me with a FSR alloy triangle, hence they sold me a carbon chainstay identical to the ones on the S-Works.

Rode it like I stole the bike for 3 more years before selling it. Two years since and the frame is still holding out fine with the carbon chainstay.

A Ralleigh might not be a bad idea ???? You will have lots of moola left to buy decent coffee ...................

A "Lifetime" is a relevant concept ............................. it all depends ????

[Mojoman]

2 minutes ago, Mook said:

Hi Mojoman,

Ja right................................... LIMITED LIFETIME ????

In defense of Spez, you will find the exact same fine print in most other big name brand warrantees, ie. Giant, Scott, etc. The definition of "LIFETIME" is 5 years, based on the expected lifetime of a frame - not the rider. Yes, only 5 years ????

This weak spot is actually a very common "weak spot" on most dual suss frames. I have personally seen Scotts and Giants break in the exact same spot on the drive side chain stay near the brace(roughly 15-25mm behind the main pivot). The carbon frames are more reliable, BUT not infallible. In my efforts to source a new alloy rear triangle, I managed to get my hands on a new carbon chain stay which fitted perfectly, barring a few slight mods ito a longer pivot bolt due to the carbon unit being bulkier than the alluminium. Spez could not supply me with a FSR alloy triangle, hence they sold me a carbon chainstay identical to the ones on the S-Works.

Rode it like I stole the bike for 3 more years before selling it. Two years since and the frame is still holding out fine with the carbon chainstay.

A Ralleigh might not be a bad idea ???? You will have lots of moola left to buy decent coffee ...................

A "Lifetime" is a relevant concept ............................. it all depends ????

Ja, the Momsen was not my first warranty claim with a manufacturer for a bike frame or parts but it sure was my worst in relation to the low level of service and general apathy from Momsen/TWT.  They have now finally paid me out though. 

And the quest for a medium 29er frame continues...Seems these days you have to buy a whole bike with crappy parts to strip it down for the frame...????
(and you need some form of telepathy/astral travelling) as bike shops NEVER get back to you with prices, stock etc....

 

[Hairy]

19 hours ago, RustyHWR said:

Maybe i was just lucky, but TWT / Momsen  refunded me in full (purchased price) for a Momsen GP300. Had a problem with the hanger on the frame that could not be fixed. Replaced the hanger a few times with no luck.

 

Did your opening line to them, when reporting the defect, start with "If you okes don't sort this out there is going to be k@k and I will moer all of you" ... that is how I would imagine your opening line would be Rusty

[RustyHWR]

On 9/30/2021 at 5:29 AM, MORNE said:

You were, took me three shipments, lots of proof, phone calls, to and fro just to GET a hanger, and axles, and headset…that were supposed to be in the box. Even funnier was I personally called and asked un double checked on here via pm too if everything was included, still got here unusable haha. 

Were you really that lucky though? Sure you got you money back but these places think they do you a favour shipping stuff out to you for free and overnight a few times after they got it wrong but they are more lucky that I don't invoice them for my time they wasted imo. 

Believe me it took almost a year to sort out. Many phone calls, Whatsapps and emails. Think it was my post on Momsen Face Book page that made them decided to pay. 

[RustyHWR]

22 hours ago, Hairy said:

Did your opening line to them, when reporting the defect, start with "If you okes don't sort this out there is going to be k@k and I will moer all of you" ... that is how I would imagine your opening line would be Rusty

You know me too well  

[Mojoman]

5 minutes ago, RustyHWR said:

Believe me it took almost a year to sort out. Many phone calls, Whatsapps and emails. Think it was my post on Momsen Face Book page that made them decided to pay. 

I went to see a friend up from CT the other night...her son proudly came into the house with his new bike...A Momsen....
Luckily the kid weighs about 15kg so the frame should hold....for a while....
Told the lad we cant go riding anymore because MY Momsen broke....????