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Old 04-17-17, 10:43 AM   #1
tcs
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Recent interview with Will Butler-Adams, CEO Brompton

Interview on March 29, 2017. About twenty minutes.


The man is passionate, and the excitement of that is infectious. The bike could be lighter and stronger if it was welded chromoly, though.
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Old 04-19-17, 03:28 PM   #2
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Thanks for the link.

What's chromoly welding?
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Old 04-19-17, 04:41 PM   #3
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Chromoly is the nickname for steel alloys containing, among other elements, chromium. Depending on the alloy and heat treatment, they can be far stronger than the hi-ten steel Brompton uses, and combined with tweeking the tubing geometry will result in a bicycle frame that's both stronger and lighter. Top quality steel bicycles moved from hi-ten to chromoly (or similar performing manganese-moly) in the 1930s~70s.

(Do I recall Mr. Ritchie once mentioning he chose hi-ten steel because his original frame manufacturing rig couldn't bend the stronger chromoly?)

The general manufacturing industry of all types of mechanical things generally moved from brazing to welding in ~1930s as well, but because bicycle frames are typically made of relatively thin wall tubing, the bicycle industry stuck with brazing, either by hand (as is still practiced @ Brompton) or in automated brazing stations. Gradually into the 1980s steel alloys and specialized techniques became available to allow reliable welding of thin wall bicycle tubing as well, creating stronger and lighter frames. This welding can be done by hand or, as is implemented in most modern bicycle factories, by robotic arms.

We had a thread were various posters offered some 20 things about the Brompton that could be improved, all while remaining true to the core and fundamentals of the bike - and, thoughtfully implemented, completely retrofittable. I only mentioned these here because Mr. Butler-Adams brought them up.

Last edited by tcs; 04-20-17 at 07:18 AM.
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Old 04-20-17, 03:21 AM   #4
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Thanks for the education.

I guess it's this thread:
Brompton: get off your ass
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Old 04-20-17, 03:25 PM   #5
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It was a good interview and every time I hear him speak, he speaks so highly of Andrew Ritchie. With the current trend of always making yourself look better and criticizing everything and everyone in sight (just read through these forums for current examples), it is heartening to hear how positive Will Butler-Adams is. In my opinion he has made the Brompton company better and I hope for continued success. Thanks tcs for posting this.
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Old 04-20-17, 04:47 PM   #6
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Wait...wait...wait...

To this day Bromptons are Hi-ten steel, not Chrome-molybdenum steel?
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Old 04-20-17, 05:24 PM   #7
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But then, he's an engineer by trade, so he can appreciate what Ritchie achieved.
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Old 04-20-17, 09:02 PM   #8
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Quote:
Originally Posted by Abu Mahendra View Post
To this day Bromptons are Hi-ten steel, not Chrome-molybdenum steel?
The last official word I read was 'hi-ten forks and frame'. I've never seen Brompton advertise a specific alloy by industry reference number. In the USA that description would mean 1020 or 1040 alloy steel - good, quality stuff but not alloys that have notable strength to weight specs. If this is no longer the case, somebody provide a link to more recent info! (One can also optionally purchase upgrade titanium forks and rear triangle - still manufactured in China from Russian Ti, or is this done in house now?)

Bromptons are also still torch brazed by hand.

https://www.flickr.com/photos/hugger...7603413318888/
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Old 04-20-17, 09:09 PM   #9
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If true, if still Hi-ten, it boggles the mind that folks pay these extravagant prices for boat anchor (figuratively) steel. I paid USD250 retail for a well-finished 4130 steel frame & fork recently.

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The last official word I read was 'hi-ten forks and frame'. I've never seen Brompton advertise a specific alloy by industry reference number. In the USA that description would mean 1020 or 1040 alloy steel - good, quality stuff but not alloys that have notable strength to weight specs. If this is no longer the case, somebody provide a link to more recent info! (One can also optionally purchase upgrade titanium forks and rear triangle - still manufactured in China from Russian Ti, or is this done in house now?)

Bromptons are also still torch brazed by hand.

https://www.flickr.com/photos/hugger...7603413318888/

Last edited by Abu Mahendra; 04-21-17 at 12:13 AM.
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Old 04-20-17, 10:32 PM   #10
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How much weight reduction can be gained by using cho-mo vs hi-ten steel? Maybe the boat anchor part is due to the hub which is close to 1 kilo. If only they use a front derailleur, that could be a bit of weight savings no? Plus you get 4 speeds instead of 3.
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Old 04-21-17, 12:17 AM   #11
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it's a question worth asking. particularly by those who are buying the thing, and paying good money.

i think chromo is also more rust resistant so it's not only about weight.

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How much weight reduction can be gained by using cho-mo vs hi-ten steel? ...
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