Story with Bowman?

fat bloke · 06-04-2022 11:25am

One thing I can't understand is how the bikes were so damn nice to ride. I still miss riding mine. You'd have thought a hastily bodged together misaligned series of tubes would ride like a dog.

What does he think of mainstream alooominum bikes from the major manufacturers? I've never heard any reviewers gushing about Giant Contends and the likes.

There's the CAAD range of course but is Hambini similarly defacatory on them? :)

ARX · 06-04-2022 12:02pm

https://www.boards.ie/discussion/comment/118888023#Comment_118888023

Giant Contends aren't artisanal.

Apropos welding, I remember reading that Ferrari had a reputation for sloppy welding. I found these pictures taken at the Ferrari museum. As I said, I know nothing about welding, but these look a bit crappy: https://imgur.com/a/5e61w

Plastik · 06-04-2022 12:06pm

I think he has undoubtedly shat all over Cannondale's (at least at one point in time) notoriously bad QC on BB30 shells. Wouldn't keep track of all his stuff, got tired of watching them after a while, but don't recall him ever taking an alu bike apart like that.

cletus · 06-04-2022 12:43pm

I watched a couple of his videos, they popped up in my feed before I knew anything about him.

I found them hard work, to be honest, even if he knows his stuff from a technical standpoint. As a result, I don't bother with his videos anymore, but when I saw the Bowman video, I wanted to see what the story was, especially in light of the company going bust, and our own fat bloke's ongoing saga.

Those Ferrari welds aren't great, either...

Mefistofelino · 06-04-2022 1:20pm

https://www.boards.ie/discussion/comment/118887703#Comment_118887703

TBH, its not that difficult in many cases. Pick an Asian firm already bulk fabricating frames in the material of your choice. If you want to "indiviualise" the design, pick angles based on the more-highly rated similar frames already on the market. Choose features based on what t'internet regards as the must-haves for that type of bike - headset bearing size, through axles, tyre clearance, BB standard, mudguard eyes etc. Then leave it to the engineers at the subcontractor to sort out the design and fabrication details. No different to personally speccing a one-off titanium frame from one of the Chinese suppliers.

There's more than Bowman taking this approach, and not just for frames either.

(One British firm did take a little more "hands-on" approach with the design where I suspect that they may have overruled the reservations of the fabricator engineers. The end result was their occasional "special offers" of cheap sample frames where it transpired they'd made some giant balls-up of a design detail)

Squidgy Black · 06-04-2022 1:24pm

https://www.boards.ie/discussion/comment/118888023#Comment_118888023

They probably had the geometry well planned out and aligned in the jig but just blasted through the welds. Or else all the pinholes were giving you enough flex to make it a lovely ride!

Mefistofelino · 06-04-2022 1:24pm

https://www.boards.ie/discussion/comment/118888183#Comment_118888183

Flow straightener (I think) from one of the display engines at the Ferrari museum..

CramCycle · 06-04-2022 3:00pm

https://www.boards.ie/discussion/comment/118888023#Comment_118888023

He hates Cannondale (from memory)and sh1t on them as a point when I first heard of him, giving out about their QC tolerance limits. The truth is though, they work, are well regarded and despite his reservations, you don't hear that many people giving out about them. Most modern BBs are designed with the ability to take those slightly wider QC tolerances, I imagine part of his issue is that his machined ones probably have little to no give in them so rather than accept that bikes aren't going to have as tight tolerances as maybe they should (which would lead to higher costs), he then has a product that isn't fit for purpose for a wide variety of frames.

As for asll the welding talk, my Dad done alot of welding (I can do a bit but not good at it) and liked it to look neat but the key component to a good weld wasn't its appearance, it is whether or not it would hold up in working conditions for what the item was designed to do. Everything else is just niceties, and such things are usually a sign the worker is good/diligent and therefore most likely the rest of the job was good but also, just because it looks nasty, doesn't mean it is.

ARX · 06-04-2022 4:09pm

https://www.boards.ie/discussion/comment/118888590#Comment_118888590

So basically he picked a bunch of options from a menu? 'Design' makes it sound like he sat down with a CAD program and y'know, designed it. From scratch like.

Mefistofelino · 06-04-2022 4:30pm

https://www.boards.ie/discussion/comment/118889684#Comment_118889684

Not saying that was specifically the case with Bowman, but "design" can have a lot of meanings. Even the person driving the CAD program isn't necessarily the "designer" in the sense that you mean it - they may just be a draftsperson, working to instructions from an engineer. And to close the loop, the initial designer, who doesn't do the actual mechanical engineering design but instructs the engineer, may bring a lot of valid experience in the specification of the item. Picking a bunch of options from a menu only works if you know what those options bring to the product.

cletus · 06-04-2022 4:48pm

https://www.boards.ie/discussion/comment/118889321#Comment_118889321

I'd agree broadly about the welding, but these welds were not good. I've done plenty of ugly but structurally sound welds. In this frame there was oxidisation holes (pinholes or blowouts), there were many points where there was no penetration on the weld, so that the bead was sitting on top of the joint, so very prone to cracking or shearing, and there were a number of places where it looked like they hadn't welded at all.

I understand your dislike for Hambini, but in this case he's not wrong

gn3dr · 06-04-2022 5:29pm

The dimple on the weld behind the seat tube was described as a blowout but it looked to me like the classic instant stop in an aluminium weld which always leads to a crater in the weld. It then becomes a stress riser / failure point. It's the classic "do not do this" from aluminium welding 101. You are supposed to back off the current slowly at the end of the weld.

cletus · 06-04-2022 5:38pm

https://www.boards.ie/discussion/comment/118890083#Comment_118890083

You're very probably right. I've never chanced welding aluminium 😁

hesker · 07-04-2022 11:49am

https://www.boards.ie/discussion/comment/118889321#Comment_118889321

So you reckon most modern BBs have give in them. Interested where you got that from as I haven’t heard that before.

cletus · 07-04-2022 1:01pm

https://www.boards.ie/discussion/comment/118893330#Comment_118893330

It's not so much that they have 'give' in them, more that they can operate properly with a relatively large tolerance.

Tolerances, in machining terms, are tiny. 10'000ths of an inch is a measurement commonly used in machining. It equates to about 0.025mm. Building things to these levels of tolerance increase the cost.

Having components that can operate even when the tolerances are (relatively) big is important in mass production

hesker · 07-04-2022 2:10pm

https://www.boards.ie/discussion/comment/118893658#Comment_118893658

What characteristics do they have that allow them to operate properly in this situation.

cletus · 07-04-2022 2:19pm

https://www.boards.ie/discussion/comment/118894030#Comment_118894030

I couldn't say for sure, I'm not an engineer, but one of the ways tolerances are allowed for would be in thread formation, whether the 'peak' of the thread has been flattened or not.

Another way might be shell wall thickness, so that ovality in the bottom bracket hole doesn't bind the bearing.

I'm sure there are other things, but I'm only a PE teacher.

There are a variety of levels of tolerance accepted in all areas of manufacturing. If a hole is specified at 10mm diameter, there is a range of sizes that might actually suit, depending on the requirements of the piece.

If I drill a hole in order to tap it, there are a couple of different sizes of hole that will suit, depending on the amount of thread engagement I might need, for any nominal hole size.

hesker · 08-04-2022 8:11pm

I think I understand what tolerances are well enough. I was just probing a line of reasoning proposed by some in this thread that to me seems really out of whack with reality.

cletus · 08-04-2022 9:12pm

https://www.boards.ie/discussion/comment/118900095#Comment_118900095

Well, if you understand tolerances, what was the line of questioning? That plug and play parts are built with those tolerances in mind? I'm not sure I understand

CramCycle · 09-04-2022 1:02am

https://www.boards.ie/discussion/comment/118900095#Comment_118900095

Apologies, tolerance would be more appropriate, I was using more layman's terms. In work we would have other terms but not used in laymans terms. Basically, there is an acceptable margin of not being in line that the BB (that you buy) can tolerate, alot of modern BBs, can tolerate these micrometers, they tolerate it through the threading on the bike and the BB not being completely flush (damn near impossible), or the pressfit taking the almost unnoticeable compression somewhere. So imperceptable that once faced off, no person on their own could tell. Some companies when QCing, allow wider criteria than they should but realistically, the bigger companies have assessed that if they apply certain criteria with a suitable level of sub sampling, that even though there will be outliers that may fail, the majority of frames are more than acceptable. There are some smaller companies that may be more stringent, which may potentially increase cost, or less stringent (if they bother at all), which will reduce cost.

To make it more simple, wheel manufacturing might be a simpler one to visualise. I know there was a video on here on how to make money quick rebadging cheap chineses wheels. Well imagine that the cost difference between HUNT or similar and the direct from factory, isn't solely the rebrand, but it is the local team QCing on this end, they may need to send X% back to the factory or scrap, depending on their business model but the mark up they charge means they can tolerate those returns and also tolerate the lower than you would get from direct sales returns, as they QC'd them locally, possibly every set of wheels.

Story with Bowman?

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