Re: [CR] Cranks and BCD, old + new

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In-Reply-To: <79A64059-777F-4EDE-ADFB-2FB20B3E0FB3@gmail.com>
References: <E1LQw88-0003ud-4S@elasmtp-scoter.atl.sa.earthlink.net>
Date: Sun, 25 Jan 2009 10:10:57 -0500
From: "Edward Albert" <ealbert01@gmail.com>
To: Kai Hilbertz <khilbertz@googlemail.com>
Cc: nicbordeaux <nicbordeaux@yahoo.fr>, Mark Stonich <mark@bikesmithdesign.com>, Classic Rendezvous <classicrendezvous@bikelist.org>
Subject: Re: [CR] Cranks and BCD, old + new


Campagnolo made a 41 tooth for the NR. not much metal there but it works. I have one. Edward Albert Chappaqua, N.Y., U.S.A.

On Sun, Jan 25, 2009 at 10:01 AM, Kai Hilbertz <khilbertz@googlemail.com>wrote:
> Jan. 25, 09 - old subject line: "Re: [CR] The Alex Singer on French Ebay"
>
> Hello Mark + List, cc George + Nick,
>
> thanks for your post, I'm quite familiar with the TA Pro 5 Vis, commonly
> called Cyclotouriste.
>
> Regarding the discussion with Jan, we ended the thread with two e-mails off
> list. Despite Nick's boxing analogy, I hope no blood was spilled. Please
> note that I've put a new subject line in this e-mail, even though it's a
> reply, because A) Jan wanted to end the previous thread, and B) I'm trying
> to answer your question, and perhaps start a new thread which doesn't
> directly relate to Alex Singer.
>
> When Jan referred to a "compact double" in his posts, both George and I
> thought he was referring to a relatively modern compact crank, most of which
> have a BCD of 110 mm. Now a 110 only goes down to 33 teeth (more on that
> later), so I was wondering about the 48/32 Jan referred to. Assuming five
> arms (rather than four or three), either this was a typo, or he was using
> something with a smaller BCD, such as a 94. If he was using a 94 BCD crank,
> 32 would be an unusual choice, since most folks go down to 30 or 29 teeth on
> a double. Turns he is using a smaller BCD, but a vintage six arm crank,
> namely the aforementioned TA Pro 5 Vis.
>
> Hillary says the Stronglight 49D was introduced in 1936, and according to
> Joel Metz, the Pro 5 Vis were introduced in 1963. In that period, there were
> no better touring cranks. Many bicyclists still like them today for their
> low width (Q-factor), gearing flexibility, and of course for the fact that
> they're period correct on many vintage bikes.
>
> However, their small BCD of 50.4 leads to a fair amount of flexing in
> larger rings. As Peter White puts it;
> "Also, the bolt circle is tiny, even for the outer chainring. This allows
> the outer ring to flex easily to the outside during upshifts, and in time,
> the gap between the ring and the arm becomes even smaller. As the gap
> between the outer and middle ring increases, the chain ends up falling
> between the two. When I was installing the Pro 5 Vis regularly on high end
> touring bikes in the 1970s, I rarely used outer rings larger than 46 teeth
> for that reason." That's the reason I don't use them, but as always, YMMV.
> Use whatever makes you happy.
>
> I'm an architect and engineer by training, though I no longer work in that
> field, and I like stiff, forged one-piece cranks with five arms. Like many
> List members, I wrench a bit (to avoid the dreaded term "tinker"). Over the
> years, I've primarily used cranks with a BCD of 144, 130, 122, 110, 94, 74,
> 58 + 56. I don't do much with the Pro 5 Vis anymore, and I've never
> personally used an 86 BCD like the Stronglight 99, but that's just me. Back
> in the 70's, I loved Campagnolo but wasn't happy with the 36 tooth low of
> the stock triple. So I made a custom triple with a Gipiemme 30 tooth low, it
> has 54-42-30. Ironically, it was 170mm, and I discovered longer crank arms
> soon afterwards, so I ended up almost never using it. I've still got it
> today, it'll be up for sale soon. To clean house, I intend to put all of my
> non-110/74/56 BCD stuff on eBay, just haven't found the time.
>
> As has been noted by Sheldon + Hillary, gearing is influenced not just by
> chainring, cog, and wheel selection, but also by crank arm length. I ended
> up mostly riding 185mm cranks, doubles and triples, so it's generally been
> TA for me. I mostly use Zephyrs, along with Vegas(180mm) and Carminas. The
> latter two aren't one-piece but hey, what you gonna do? But then crank arm
> length would probably constitute a whole 'nother thread, and I would like to
> return to your BCD question.
>
> As far as I know, Campagnolo never made anything smaller than 42 teeth for
> their NR/SR cranksets, but TA did. I've still got a vintage, not modern, 41
> tooth TA chainring for Campagnolo, it's eBay bound. TA also made and makes
> 38 tooth chainrings for 130 BCD Shimano-style cranks, and of course they
> make a 33 tooth chainring for 110 BCD, I own several. On doubles, I mostly
> use 50-33 or 48-33. Like the 41/144 + 38/130 BCD rings, 33's have to be
> relatively thin to fit the spider. Peter White sells them for around 50
> bucks.
>
> Your sign-off "28-42 compact double with a 14-28 FW" was interesting. I
> checked the archives, my questions to the List concern what kind of cranks
> and gearing other folks are using on their vintage and KOF bikes:
> 1. What BCD do YOU like, i.e. are most folks riding (Campagnolo) 144 and/or
> (TA+Stronglight) 50.4, or is there a sizeable minority of others? 122
> anyone? Or do we have lots of collectors with almost as many BCD's as bikes?
> 2. Are almost all using vintage cranks, or do other heretics besides George
> and myself also use classical style but post '83 cranks like TA Zephyrs,
> Sugino compacts etc? (Hope that question is OK, Dale)
> 3. Do we have mostly racers and randonneurs with doubles, or a bunch of
> triples as well? What gearing do YOU like?
>
> Greets
>
> Kai Hilbertz
> Munich, Germany
>
>
>
>
> On 25.01.2009, at 04:58, Mark Stonich wrote:
>
> At 1/24/2009 07:37 PM +0100, Kai Hilbertz wrote:
>>
>>> Hello Jan, cc List,
>>>
>>> do you personally prefer 48/32, as stated? That would mean a BCD of 94
>>> (or smaller), and then you could go smaller with the inner chainring.
>>> Or were you referring to 48/33 or 48/34 with a BCD of 110? What do you
>>> use in the rear?
>>>
>>
>> Kai,
>> With the TA Cyclotouriste a 26t inner ring on a double is possible.
>> With the 86mm Stronglight 99 a 28t inner ring on a double is possible.
>> I imagine the constructeurs were making whatever they needed.
>>
>> Have you ever seen a 33t 110mm bcd ring? I haven't.
>>
>> Mark "28-42 compact double with a 14-28 FW" Stonich;
>> Minneapolis, Minnesota USA