That sounds like an old French steel Solida cottered crank, so the BB cups "S" is probably Solida also. Is it steel with the arms held on with cotter pins? If so, this crank was pretty heavy and not rare or valuable, so it would probably be better to replace the crank and BB. With a French crank, one is always afraid the BB cups are French threaded, but if it is a Coventry Eagle frame, it is almost certainly English BB thread, which is essentially the same as modern ISO, so finding a new BB to fit the frame should not be a problem. Personally, on an English mixte frame, I'd use a TA or Stronglight crank, but a Campy crank and BB will be easy to find if you are willing to pay the price. As to crankarm length, 175 is noticeably different from 170. Also, unless your wife is quite tall, 175 is probably too long for her. Most average sized American women would ride 165 cranks, rarely more than 170.
> I do not know kind of crank it is, but here are the markings on it. On the
> crank arms, outside - SOLIDA, inside - D6 21 Made in France, on the
> chainring - Made in France, the BB caps - a capital S, Made in France. So I
> am going to assume it is Simplex. There looks to be provision for an inside,
> smaller chainring, but finding one could be a trick. I do not have a problem
> changing the whole bottom bracket, if I need to.
> This is the first time I am going to attempt a complete rebuild, so I
> appreciate any advice given. I have decided to stay with a 5 speed
> freewheel, that should make our choices a bit easier.
> P. Lynn Miller
> ----- Original Message -----
> From: "jerrymoos" <email@example.com>
> To: "P. Lynn Miller" <firstname.lastname@example.org>; "Classic Rendezvous"
> Sent: Monday, October 13, 2003 11:54 PM
> Subject: Re: [CR]Campagnolo Advice Needed
> > You can't usually fit a 6-speed FW in 120 rear spacing, but SunTour in the
> > early 80's made "Ultra-6" narrow spaced FW's that would fit 6 cogs in
> > rear spacing. A few others copied the idea. If you don't go bigger than
> > or 28T tops on the large rear cog, you can use the Campy Nuovo Sport
> > derailleurs. You can certainly buy a Campy Nuovo Record or Super Record
> > crankset, but these are expensive. You can buy Campy Grand Sport,
> > or Triomphe cranks cheaper, but the Victory, Triomphe and some versions of
> > Grand Sport used unique sized chanirings which are now difficult to find
> > all the sizes you might want. A modern Campy Mirage is relatively
> > inexpensive and chainrings are easily available. It is possible you could
> > add another chainring to the crank on the bike. What kind of crank is it?
> > Note that if you change to a different crankset, and possibly even if you
> > just add a chainring, you will probably need to change the baootom bracket
> > axle or perhaps the whole botom bracket.
> > Regards,
> > Jerry Moos
> > Houston, TX
> > ----- Original Message -----
> > From: "P. Lynn Miller" <email@example.com>
> > To: "Classic Rendezvous" <firstname.lastname@example.org>
> > Sent: Monday, October 13, 2003 8:14 AM
> > Subject: [CR]Campagnolo Advice Needed
> > Good day,
> > I am in the process of reworking my wife's mixte, which is a Coventry
> > a very nice light lugged steel frame made from Tubi Oria Cro-Moly. It
> > currently is a five speed using mostly Simplex parts in the drive train,
> > Maillard? hubs with no name 700C rims, and Wienmann brake levers and side
> > pulls. I am not sure what year it is, but it is a very nice looking and
> > handling bike.
> > I want to add a chain ring or change the crank set to have 2 chain rings
> > front. It has 120mm spacing on the rear, so I am not sure what the maximum
> > amount of cogs I can get in that space. I want to use all Campagnolo
> > does not need to be from the same vintage as the frame or even all need to
> > be a certain group. This choice is the result of me picking a bike up
> > side the road with Campagnolo parts. The frame is too large for anyone in
> > household but it does have Campagnolo Gran Touring Novou front and rear
> > derailleurs with down tube shifters.
> > So can anyone tell what groups or vintages to look for that would allow me
> > to build a high quality yet economical bike for her. There seems to be a
> > huge array of groups, names and vintages out there. I planning to replace
> > the parts in this order -
> > Drivetrain - I have the front and rear derailleur and shifters, need to
> > the crankset and freewheel. Can I fit a 6 speed in 120mm?
> > Hubs and rims - Need to source all parts. Since this is mostly a touring
> > bike, what the best spoke count? Front & rear?
> > Brakes - Levers and callipers - need to source all parts
> > Also how difference is there practically between 170mm cranks and say
> > Thank you for your time
> > P. Lynn Miller
> > http://members.optusnet.com.au/