I was thinking of getting a granny gear set up but don't want to replace the crankset. A triplizer is available but I need to order the correct size.

What is the bolt circle diameter of the old Nuovo Record and Super Record cranks?



Who makes small chain rings compatible with the old (~1970) Regina Oro 5 speed chains?



Is there a standard amount of extra spindle length needed to install a triplizer?


Is it just an extra chain ring's width plus the inter-ring gap? Can I measure the tooth-to-tooth spacing on the existing chain wheel and use that?

If you are talking of the 1970's, the days of the 42 tooth ring being the smallest (except for the fabled and seldom seen 41s), the BCD was 144. Still is on many track cranksets like the Sugino 75.

I'd google Sugino, 144 BCD and 3/32". I think you can just turn outside rings around and use them on the inside (but I haven't tried it). Seems to me I would have heard it wasn't possible in my days when the 52-42 crankset was the gold standard and I was hanging out with some very innovative mechanics, one of whom has since achieved some fame as the man to go to with questions like this. Sadly, he passed a couple of years back.

Ben

Yes, I have a 1970's Campagnolo Nuovo Record crankset with a 42/52 chainrings.

I want a smaller inner ring than 42 teeth, hence, the triplizer.






<Well, I'm headed out for a ride. It's HOT!>

You could do that. In practice you may need less extra space than that because the chainstays taper outward slightly and the granny chainring has more room. Regardless it's not necessarily a bad idea to try on 5mm longer as a first guess.

Also, minor differences in BB spindle taper will change how far the crank sticks out. ISO and JIS differences aren't quite as cut and dried as you might think, but even so, stick with ISO. It may actually be easier to fit a new BB than try and find an NOS campy spindle in the correct length for a triple.

You may actually want to have an LBS do this, because sometimes it takes a couple try and fits to get the right size.

The only currently available triplizer for that crank is this one: 144 BCD Triplizer, 42 Teeth He has some info on his site regarding bottom brackets.

Yes, Sugino's 144mm rings were symmetrical and could be used in either position. I have also made close-ratio triples, such as 54-50-47 for a Bikecology customer and 49-46-43 for myself, using long stackbolts.

However, our thread starter wants something smaller than 42T. The only other option, of course, is to go larger in back, presumably with a new derailleur cage or entire rear derailleur.

Thanks for the help.


Triplizer chain ring: $ 91
Nuts & bolts set: $ 18
30 tooth chain ring: $ 65
Bottom bracket: $125 (already have Phil Wood tools)
Rear derailleur: $ 50 (already have Shimano Deore XT)
Longer chain: $ 25
New shifter cable: $ 5


TOTAL: $379 + shipping and tax


So it will cost about $400 to do this. Oof!

I already have a 13-32T Ultra-6 freewheel for the rear and a Shimano Deore XT high capacity rear derailleur. These are not yet installed.


I am considering what it takes to match that up with a triple chain wheel crank. In the mean time, I will continue to grind my 42X24 low gear up the various little hills we have around here (the Rocky Mountains, ).

There are 41T rings for 144mm BCD from Campagnolo, TA, and Ofmega (possibly others as well), but the difference in gearing from a 42T ring is minimal (and may require some modification of the spider arms to provide chain clearance) and probably not worth the bother of trying to find the 41T ring.

I ran across some of those last night while looking for small &$ BCD chain rings. I saw Avocet and at least one other maker. A one tooth reduction is not worth it to me.

In fact, I am not going to spend $300-400 on this conversion. I am going to explore other options, first.




Thanks to all for the help.

I wouldn't spend $400 for this conversion either.

There are modern cranksets that don't look out of place on an old bike and will give you better climbing gears. You could go with a modern square taper compact crank (usu. a 50/34):

Defiant Compact Road Crank ? Interloc Racing Design / IRD

Or you could use a "wide" compact (usu. a 46/30):

IRD Defiant Wide Compact Road Double Crank Set (46-30T)

Grand Cru 50.4 BCD Crankset MK II

Yup, found a new (NOS) 41T/144BCD ring from TA a few years ago when digging through an old dealers back cabinets. As noted, it's not much of a difference on the road but confirms officially to me that the minimum inner ring size for the standard (No threaded holes and flats on the spider arms for tripleizers) double 144BCD crankset, is 41T....

$400 if you're trying to make it an expensive project. Oof!

144 is still a Track crank standard .. earlier, pre '67 they used a 151 bcd.

Ref: Sutherlands.

You can also drill holes in your crank arms for a third ring. Many did this back in the day, mirroring Campy's own triple Record crank. Your cost would be a relatively generic inner ring, and some somewhat hard to source bolts for it. Oh, and a drill and tap set.

You have a Record crank with Nuovo Record rings.

Where is [MENTION=52458]jonwvara[/MENTION] ? Paging jonwvara...

If your crank was 144mm BCD originally, then chances are it is still 144mm.

And, as I noted above, some modification of the spider arms may be needed to provide chain clearance. Avocet/Ofmega did this at the factory:

I'm sure you are correct. Thank you for the help.



I think my 52T ring is actually Super Record and the 42T is Nuovo Record but that makes no difference to the point you raise.

[MENTION=172094]Chombi[/MENTION] too...

I have a few of them, TA and Campy even a NIB/NOS Campy NR 41T chainring. It's only a 1" reduction in gear ratio with a 28T rear sprocket, even less with a 32T sprocket!

I may have one on a bike but the rest are part of my collection of rare junk. It's not worth the time to change rings for 1" or less lower gear!

As far as modifying the crank arm, I run 38T small chainrings on most of my 130 BCD cranks. On some of them that were made for a 39T minimum, I've had to file a little off of the crank to prevent the chain from rubbing.

verktyg

Chas.

I can vouch for Jon's tripleizer ring, having set up a NR conversion myself:



Add 5mm to the drive side spindle length and you're good to go.

Top

I agree that Jon's Tripleizer is the best option.
But I think the OP rejected the idea early in the thread, because of cost.

Triplizer chain ring: $ 91
Nuts & bolts set: $ 18

Bottom bracket: $125 (already have Phil Wood tools)



30T chain ring: $ 0 (may have in parts pile)
Rear derailleur: $ 0 (already have Shimano Deore XT)
Longer chain: $ 0 (found an Ultra-6 chain)
New shifter cable: $ 0 (arrived in mail yesterday)


So, I have beaten the cost down to under $250.

I'm going to install the wide range freewheel first and evaluate if I need more and whether I like the gearing. Then, I'll think about the cost-benefits of a Phil Wood vs Shimano bottom brackets purchase ($).

Others that have been offered:

Framebuilder Bernie Mikkelsen of Oakland California offered a triplizer c/w for the 144 bcd in two or three different dentitions back in the 1980's. One more name to search for...

Framebuilder Jim Merz of San Jose California offered inners for the Campag Record/Nuovo Record triple of 31 & 30T. The only inner offered by Campag was 36T.

Wouldn't you also need to replace the Campy BB and the front derailleur for a triple? Otherwise, I don't see how the chainrings would be centered properly and get decent shifting on the front. Maybe this older BCD was why Giovanni Battaglin used a triple.



https://www.cyclingweekly.co.uk/news/...narello-174073

Edit: after reading the above article, the 36T inner ring was added onto a double crankset. Seems they kept the same BB and Q-factor (pedal spacing). Interesting...