Thanks, Jon. I wasn't aware of the Wheelsmith triple conversion. Seem s WS offered all sorts of nice goods and services. I have been using my Wheelsmith spoke tension meter for about 20 years now. Does anyone know when these went out of production or if the new owners of Wheelsmith have a ny plans to reintroduce them? I think one used to be able to send them b ack to Wheelsmith for recalibartion every few years for a reasonable charge . Does anyone offer this service now?
Speaking of triples with drilled spiders, I'm now convinced that standard m etric fasteners and chainring spacers will work just fine in this applicati on, at least for the M6 x 1 bolts. The trick will be to use the proper t hickness spacer. But there is no guarantee that the Avocet bolts will ha ve the right spacing for another crank. Sounds like they worked for the WS converted Campy NR, but on my Stronglight 107 triple it appears that whi le the Avocet bolts have the right thread, their spacers are probably too t hick and will give too wide a gap between the middle and inner ring.
One problem with chainring spacers is that they have gotten very expensiv e lately. The only new ones I've found of late sold separately, rather than in chainring bolt sets, are Wheels Manufacturing. but these are now nearly $1.00 apiece retail, and more than 50 cents at wholesale. Anyo ne know a souces for less pricey chainring spacers? I may have to su rvey the hardware store to see if there is a cheaper generic replacement. One would probably need to do that anyway for triples with M5 x 0.8 bol ts, since chainring spacers will have too large an ID.
All this, plus my recent experience with the overengineered (by Schwinn m ost likely) TA cranks on my Sports Tourer raises a question I've alway wond ered about. Was there ever a standard spacing between chainrings, or was every marque a bit different? There obviously can't be a huge variation , since too small a spacing will cause the chain to rub, while too large a spacing will cause the chain to drop between chainrings. But there might easily be a variation of a couple of mm that would still work. Anyone k now if there was any sort of standard, and if so what it was?
Regards,
Jerry Moos
Big Spring, Texas, USA
From: Jon Spangler <hudsonspangler@earthlink.net> Subject: [CR]Re: Drilling Campi NR cranks for triple gearing To: "Dale Brown" <classicrendezvous@bikelist.org> Date: Friday, September 19, 2008, 2:18 AM
Folks,
I paid $20 or $25 to Ric and Jon Hjertberg at Wheelsmith in Palo Alto during the 1980s for one of their locally-famous Campagnolo NR crank- based "triple conversions." (They then occupied the tiny "shack" next to what was then Sierra Designs' retail outlet on Alma Street.) Because I had previously worked at Avocet/Palo Alto Bicycles, I was familiar with the conversion hardware, at least on my cranks. (There may have been other options available from Wheelsmith (WS), but could not tell you what they were.) I will forward this email to Ric and ask if he would like to shed more light on the subject of the WS triple conversions.
I have also recently checked the threading on the WS-added holes against both local hardware store stock and lots of parts in my miscellaneous boxes to verify the threading.
For that princely sum of $25, Wheelsmith drilled and tapped 6M x 1 holes in a 74 mm BCD pattern all the way through my Campi NR spider arms and supplied a set of Avocet's 6M x 1 inner chainring bolts. I then fitted a 30t Avocet inner ring (any other five-bolt 74 mm BCD ring also works, of course) to my previously-double crank with a longer Phil Wood BB. I managed pretty well dropping from a 41t middle ring (hard to find even then) to a 30t inner with my Campi NR derailleur. I do not remember whether I managed to make my NR RD work on that rig, too, but I think it just barely did.
It seems like you could re-drill and tap an existing triple spider with M5 x .8 holes and make them M6 x 1, if all you can find are the larger Avocet inner ring bolts, which have a rather conical shape to fit against the arms and maintain the correct spacing. My 1974-ish NR cranks have held up fine with the additional holes and the resulting weakening of the arms, and a more modern spider with better metallurgy would most likely do very well with M6 x 1 holes in it, too.
Since Avocet cranks and rings were manufactured (I think) by Ofmega, one might be able to find compatible hardware through Italian sources.
Having lived with a permanently weakened right leg since a 1970 rock climbing accident, I can offer Jerry and others the advice I received 30 years ago: "Don't ignore the advantages of using a triple crank. Take care of your knees--they are the only ones you've got."
(While knee replacements are now commonplace and easily available, the replacements are not as good as the OEM parts, and are very pricey. And you thought that a restored Hetchins with all-NOS Campi Super Record was expensive? :-)
The bonus was this: the very first time I climbed Old La Honda Road-- the site of regular uphill time trials in Woodside--I reached the top at Skyline Boulevard faster than I had ever managed it before, because I was spinning higher pedal RPMs with my new triple gearing. Go get them granny gears!
Jon Spangler (who is now 56, and has enjoyed this trip down memory lane, reminiscing about "back in the day") Alameda, CA USA
Responding to Jerry Moos:
>
> Date: Thu, 18 Sep 2008 13:36:31 -0700 (PDT)
> From: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net>
> To: Classicrendezvous@bikelist.org, rapidfire10ring@hotmail.com
> Subject: Re: [CR]Seeking the "tripleizer" for tapping the Campy
> crank to a
> =09triple
> Message-ID: <686264.97292.qm@web82204.mail.mud.yahoo.com>
> In-Reply-To: <680774.39485.qm@web51610.mail.re2.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
> MIME-Version: 1.0
> Precedence: list
> Reply-To: jerrymoos@sbcglobal.net
> Message: 2
>
> Well, having dealt with a few such cranks of late, I would not
> recommend ta
> pping the holes at 100 BCD unless the crank is in fact a Campy NR
> double wh
> ich you are trying to convert to as close to an original Campy NR
> triple as
> possible. Campy NR is the only such crank I know of that uses the
> 100 B
> CD circle, and I've never seen a Campy 100 BCD ring in anything but
> 36T, ev
> en though the circle should allow 32T, maybe even 30T. I believe
> (Jim?)
> Merz did make some rings as small as 32T to fit the Campy NR
> triple, but go
> od luck finding one of those, so unless one of the modern Campy
> triples use
> s 100 BCD for the inner ring, you will be limited to 36T, which is
> much lar
> ger than that circle should allow.
>
> Avocet/Ofmega triples actually have two sets of inner drillings.
> The lar
> ger is 102 BCD, which is unfortunate, since if Ofmega and Campy had
> used th
> e same circle, at least those two brands could have interchanged.
> Kind o
> f like Zeus and Stronglight doubles being only 2 mm apart at 120
> and 122mm.
> Avocet/Ofmega 102 rings are available in several sizes, the
> smallest be
> ing 32T I believe, but they are becoming somewhat rare. A much
> better ch
> oice might be the smaller Avocet inner circle of 74 BCD. There are
> a lot
> more Avocet/Ofmega rings around in that circle, plus many more
> recent, tho
> ugh not necessarily current, cranks used 110/74 circles, so there
> should be
> lots of 74 mm rings around.
>
> I've been messing with a Stronglight 107 triple of late. Models
> 106 and
> 107 had gone to a 144 double circle, but the 107 (and perhaps 106)
> triple w
> as drilled at 86 BCD. That made sense, since that was the
> Stronglight mo
> d 99 circle. There were a lot of Mod 99's made, and they used the
> 86 mm
> circle for all rings and were frequently configured as triples, so
> mod 99 r
> ings in sizes suitable for an inner triple are still pretty easy to
> find.
>
> The other triple with the inner holes tapped into the spider arms
> I'm a lit
> tle familiar with is the TA Tevano, or at least I'm familiar with
> the inner
> chainring bolts. I bought three sets hoping the would work for
> the Stro
> nglight 107 or Avocet, but they do not. Chris Kulczycki at Velo
> Orang
> e was until recently selling some Tevano arms that appeared to me
> to be dri
> lled for an inner ring, although I don't think he discussed that
> capability
> . Don't know what the cirlce is, but probably Chris does. It
> might be
> the Cyclotourist inner circle, although this would offer no
> advantage, as
> the Cyclotourist inner rings are 6 hole, while the Tevano is a 5
> arm Campy
> clone.
>
> So I think that other than to replicate a Campy NR triple by
> drilling NR
> double rings at the same BCD, you are best advised to use either a
> 74mm o
> r 86mm circle. But the other question is the hole size and
> thread. Af
> ter receiving the Tevano bolts, I found they are too small to fit
> Stronglig
> ht 107 or Avocet triple cranks. However Avocet bolts do work on
> Strong
> light 107, and it turns out both appear to use a standard M6 x 1
> thread.
> The Tevano looks like 5mm, possibly a standard M5 x 0.8 thread.
> Anyone
> know what the Campy NR triple uses? If it is 5mm, maybe the Tevano
> bolts
> will work on the Campy arms. Last weekend I put together the
> Strongligh
> t 107 triple, using standard M6 x 1 bolts and chainring spacers.
> It look
> s like M6 x 1 stainless socket head or button head bolts either 16
> or 20 mm
> long will work best, with chainring spacers somewhere between 7
> and 11 mm.
> It looks like the spider arm thicknesses and profiles vary enough
> that
> different thickness spacers will be required for different brand
> arms, and
> Tevano and perhaps Campy will require M5 rather than M6 bolts.
> I'm not
> at all sure I have the right spacers to give the optimum spacing
> between mi
> ddle and inner ring, may have to actually install the crank on a
> bike to so
> rt that out. I'm also going to check my Campy triple to see what
> size th
> e holes are. Someone told me offlist that he bought some Avocet
> inner bo
> lts to use on a Campy and they didn't fit, so I assume Campy is
> something o
> ther than M6 x1.
>
> It is no doubt a sign of age and weak legs that I have to begin
> researching
> triple chainrings.
>
> Regards,
>
> Jerry Moos
> Big Spring,Texas, USA
>
Jon Spangler
Writer/Editor
Linda Hudson Writing
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