... sorrry, i have three, and another three on the other side on my leg. have no idea what the plates are made of ... anyway i am so fucking tired of these discssions of bolt sizes i have a "@@@" i saved all my money for it. got all the bits too now. Sweet Dale, I apolize (must be the the pain pills)
r clair
alexandria, va 222308
<classicrendezvous@bikelist.org> Sent: Saturday, December 22, 2007 3:11 PM Subject: Re: [CR]Chainring Bolt Sizes
> You are correct. I have accumulated a number of these recently. 116 BCD
> was the standard, and most used 9 mm bolts as compared to 10 mm for 5-arm
> cranks.
>
> One nice aspect of this is that you can actually equipe the old
> Stronglight 3-arm steel cranks with more recent alloy rings. This also
> allows much lower gearing as the old steel rings and even many older alloy
> rings attached to a carrier that attached the actual rings at a BCD
> greater than 150 mm. The Stronglight steel arms were very high quality
> and elegant, and, when equiped with alloy rings, really aren't that much
> heavier than modern cranksets.
>
> Most of the variation is in how a second ring is attached. The steel
> arms usually had threaded holes to attach the steel ring carriers to the
> arms from behind. The rings themselves, alloy or steel, are 157 BCD. TA
> Professional 3-arm alloy cranks attach both rings directly to the arms
> with one set of bolts, one outside the arm, one inside, just like 5 arm
> cranks. Nervar alloy 3-arm are a little different in that both ring
> attach inside the arm.
>
> Campy Sport (cotterless) steel and Grand Sport 3-arm alloy attach the
> outer ring to the outside of the arm, but then the inner ring attaches to
> the outer at the 144 BCD circle used on the 5 arm Campy NR/SR. This means
> the smallest inner ring is 42T (well theoretically 41T, but I doubt a 144
> BCD 3 hole 41T ring was ever made). On the old Campy Sport cotterless
> steel I have, the inner ring is riveted to the outer. On the alloy GS
> 3-arm crank I have the inner is bolted to the outer. The inner ring seems
> to typically have been 42T.
>
> One thing that initally puzzled me is that Stronglight made a 6 hole 116
> BCD ring with 9 mm bolt holes. Were these for some 6-arm Stronglight
> crank I never heard of? I've now concluded these were made for 3-arm 116
> BCD arms, probably initially the Stronglight steel cranks. Three holes
> attach the ring to the arms, the other 3 attach the inner ring to the
> outer. One interesting detail supports this. Stronglight 3 hole 116 BCD
> inner rings, unlike TA, have the inner web cut away at a point halfway
> between each pair of bolt holes, i.e. exactly where the extra 3 holes
> would be on the 6 hole rings. Why? Well, when these inners are used with
> 6 hole outers, the cutaways allow clearance around the bolt heads where
> the 6 hole rings are bolted to the inside of the Stronglight steel arms.
>
> Ain't this old French stuff interesting?
>
> Regards,
>
> Jerry Moos
> Big Spring, TX
>
>
>
> Amir Avitzur <avitzur@013.net> wrote:
>
> I just checked a bunch of 3-Arm cranksets for interchangeability.
>
> All are 116 BCD and, surprisingly, all have 9.2 ~ 9.4 mm holes for 9mm
> diameter chainring bolts.
>
> * TA Pro 3
> * Nervar
> * Campagnolo steel GS
> * Stronglight steel (threaded with 9mm lip for chainring)
>
> * Stronglight Aluminum rings
> * Cyclo Steel Rings
>
>
>
> I may be mistaken, but all the classic 5-arm cranks I know have 10mm Dia
> chainring bolts.
>
> Funny, the distinction.
>
>
> Amir Avitzur
> Ramat-Gan, Israel