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Tripilizing Serotta, Dura Ace, help!

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Tripilizing Serotta, Dura Ace, help!

Old 02-04-20, 12:59 AM
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jackbombay
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Tripilizing Serotta, Dura Ace, help!

My buddy lives in Alaska and has this Serotta, He lives on a notable hill and needs some lower gears. The bike hasn't been ridden in some time.

Chain, cassette (freewheel?) and a rear derailleur for sure, I imagine, and, does anyone make a tripilizer for this crank? And I imagine it would need a new BB spindle to space the crank further from the DS chain stay for the tripilizer to work?

Here are some pics.







Thoughts?

I do need to be walked through this to some degree. I'll be visiting him in July and would love to set his bike up proper for him then, but I will give it a good send off in its current form, I should be fit when I show up there and I do intend to go smash on his bike as hard as I can for a proper send off before it gets modified...

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Old 02-04-20, 01:50 AM
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There are people who have drilled the Campagnolo Nuovo Record spiders for triple rings, and I've thought that would also work on the flat Dura Ace spiders.

However, the Willow type triplizers should also work without modification of the crankset.

Shimano 6703 triplizer parts are also still available, but would require machining off the shelf for the inner ring.

Hopefully your front shifter would be agreeable with the triple, but I doubt the front derailleur would be.

If you upgrade the derailleur, look for a cyclocross style triple derailleur. DO NOT USE A MTB DÉRAILLEUR. The MTB Dérailleurs sit too far behind the seat tube.
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Old 02-04-20, 02:04 AM
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Originally Posted by jackbombay
does anyone make a tripilizer for this crank? And I imagine it would need a new BB spindle [snip]
Yes, several companies made triplizers that'll work on a DA crank -- TA, Willow, FSA, Stronglight, and Thorn (SJS Cycles) come to mind. Search for 130 mm BCD, not Dura-Ace, because they fit more brands/models than just Dura-Ace. And since triplizer is not a standard industry term (yet), watch out for alternative spellings, or completely different words for it.

I recommend not getting a Dura-Ace triplizer though, ironically not a good choice for your friend. The had a non-standard 92 mm BCD for the granny, that will only take Dura-Ace Triple rings, which only came in one size (30t), no choice and poor availability. Also, to mount on a DA double crank, you'd have to saw off the 5 shelves on the inner side of the spider arms. Almost every other triplizer on earth goes around those shelves somehow, so you don't have to cut them off. IMHO the Dura-Ace triplizer is a stupid design that should never have existed, and whoever designed it should be fired! Here's a pic of the stupid one to avoid:


Yes you'll probably need a longer spindle, typically about 3 to 5 mm longer on the right. If you can only get symmetrical spindles then that'll mean 3 to 5 mm longer on the left too, for a total of 6 to 10 mm wider. Some have side-to-side adjustability, so you can get one that's wider by less than that, and offset it to the right. Sometimes with a spacer under the fixed cup. Just make sure the left crank doesn't hit the left chainstay out at the pedal end, which is when you know you have offset it too much.

Another alternative is a deeper indent in the outside of the right chainstay, to minimize the axle length (and Q factor). But that's risky on a lightweight frame, unless done with sensitivity and skill. Amateurs have succeeded in ruining some nice frames that way.

Here's a bike Battaglin used to win the 1981 Giro. If a pro can use a triple to win a grand tour, who are we to give it the side-eye?


Note the very deep indent in the chainstay, and note also the Super Record titanium spindle, which only came in a double. So this triple has the same chain-line as a double, with the "granny" only lining up well with a few of the largest cogs in back. I like that in a drivetrain, but the deep indent inevitably takes out some of the strength and stiffness of the stay, so it's a trade-off. Remember, if you use a smaller granny ring, then the indent doesn't need to be as deep. Battaglin's was a 36t, kinda large as triples go. Most people wouldn't bother triplizing unless they need a low gear a good bit lower than that. If you want say a 30t or smaller, the indent needed would be less heinous. Typical triplizer rings take a 74 mm BCD granny, so 24t minimum.

You can also combine these methods -- chainline a bit narrower than a normal triple, but not as narrow as a double. Maybe with a small indent, or fiddle with the chainline until you get it as narrow as you can with no indent, or whatever clearance the frame has already. Often a round-oval-round (or fully oval) chainstay will have decent clearance for a small granny like 24t..

Sorry I can't give you a one-size-fits-all answer -- "it depends".

Mark B in Seattle
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Old 02-04-20, 02:23 AM
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Originally Posted by bulgie
I recommend not getting a Dura-Ace triplizer though, ironically not a good choice for your friend. The had a non-standard 92 mm BCD for the granny, that will only take Dura-Ace Triple rings, which only came in one size (30t), no choice and poor availability. Also, to mount on a DA double crank, you'd have to saw off the 5 shelves on the inner side of the spider arms. Almost every other triplizer on earth goes around those shelves somehow, so you don't have to cut them off. IMHO the Dura-Ace triplizer is a stupid design that should never have existed, and whoever designed it should be fired! Here's a pic of the stupid one to avoid:
The 7703 isn't all that bad, but replacement parts are almost non-existant. And, like you said, rather non-standard. I do like the octalink, and I think the cranks may be hollow too.

The 6703 parts are moderately compatible with it though, and still available.
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Old 02-04-20, 02:37 AM
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I'd probably look around for a 6503 crankset and BB. Have one on my Lemond, swapped out the 30t stock little ring for a 26T for excellent climbability.
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Old 02-04-20, 05:20 AM
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The FC-6206 is also a good choice. Looks just like it except for SHIMANO in place of the DURA ACE. The required 121.5 spindle is still easy to get.
You might need a new FD. Check the original FD to see if it will swing/move enough.

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Old 02-04-20, 07:39 AM
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Willolw triplizer on 7400 crank.
Works fine for me.

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Old 02-04-20, 07:59 AM
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Don't know about that hill or the rider, but there is still some room for a fair bit of improvement within the current set-up. It can handle a 38T inner chainring and a 28T largest cog without having to change anything else.

Just my 2 cents.
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Old 02-04-20, 08:04 AM
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I would use any of the shimano mtb triple cranks (110/74 bcd square taper) but use only the outer two rings. With any luck, you’ll be able to use the same bb. Run a 50/34 up front and an 11-32 in the rear. You will need a crank, a new rear derailleur, a new chain and cogset. For a rear derailleur, I’d find a clean used older Deore Xt or a shimano long cage rd or a microshift,

one problem may be the shifters. The older dura ace was not compatible with non dura ace rds. I don’t know the generation dura ace on this bike so you’ll have to do some research.

its not a no brainer to triplize a road racing bike as the chain stays are short and you may run into some issues. A compact crank will be easier to set up.

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Old 02-04-20, 09:53 AM
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Originally Posted by bikemig
I would use any of the shimano mtb triple cranks (110/74 bcd square taper) but use only the outer two rings. With any luck, you’ll be able to use the same bb. Run a 50/34 up front and an 11-32 in the rear. You will need a crank, a new rear derailleur, a new chain and cogset. For a rear derailleur, I’d find a clean used older Deore Xt or a shimano long cage rd or a microshift,

one problem may be the shifters. The older dura ace was not compatible with non dura ace rds. I don’t know the generation dura ace on this bike so you’ll have to do some research.

its not a no brainer to triplize a road racing bike as the chain stays are short and you may run into some issues. A compact crank will be easier to set up.
This is quite likely the way to go for what he is looking for, I know the gears will be spaced fairly far apart, but I doubt that will matter to him. I may even have a crank that would work for him.

This 6 speed rear end is a freewheel, yea?
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Old 02-04-20, 10:00 AM
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Originally Posted by non-fixie
Don't know about that hill or the rider, but there is still some room for a fair bit of improvement within the current set-up. It can handle a 38T inner chainring and a 28T largest cog without having to change anything else.

Just my 2 cents.
The hill is ~1000', I've not ridden a bike up it, but have driven up it and it is a bit of a bruiser for someone that isn't currently in shape and has a bit of extra weight on him like he does currently. The hill averages %7 for 2.5 miles,

https://www.strava.com/segments/4871894
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Old 02-04-20, 10:02 AM
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Thanks for all the options guys!

I'll get some pricing added up for the various options he has and chat with him about the pros and cons of each and go from there :-)
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Old 02-04-20, 10:10 AM
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I’d just replace that crankset with a compact double. Lots of options out there. That might also mean not needing to replace the bb spindle or FD.
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Old 02-04-20, 10:16 AM
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Originally Posted by jackbombay
This is quite likely the way to go for what he is looking for, I know the gears will be spaced fairly far apart, but I doubt that will matter to him. I may even have a crank that would work for him.

This 6 speed rear end is a freewheel, yea?
The 6 speed rear end could either be freewheel or cassette. Does your rear hub have a bulge in it near the drive side? If so it is a cassette.
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Old 02-04-20, 11:00 AM
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All good ideas. Here's another: replace the crankset with an 86 BCD one like an SR Apex (they were made in multiple BCD's, so check) and put on 50/28 rings. No need to change the BB. That FD will suprisingly shift that combination just fine and with a 28 big cog out back you can keep the current RD and wind up with a 1:1 ratio, same as a compact with a 34 and a different RD.

I used that exact combination on my Faema Merckx at the Coppi event inWisconsin last year, worked a charm. And there are LOTS or steeper hills than that in that part of WI!
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Old 02-04-20, 11:19 AM
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Originally Posted by rccardr
All good ideas. Here's another: replace the crankset with an 86 BCD one like an SR Apex (they were made in multiple BCD's, so check) and put on 50/28 rings. No need to change the BB. That FD will suprisingly shift that combination just fine and with a 28 big cog out back you can keep the current RD and wind up with a 1:1 ratio, same as a compact with a 34 and a different RD.

I used that exact combination on my Faema Merckx at the Coppi event inWisconsin last year, worked a charm. And there are LOTS or steeper hills than that in that part of WI!
There is one for sale on ebay now, tripled to 50/45/28, I doubt he wants the big gears so I could set the crank up 45/28 with a 28 big cog in the back and the total package would be the crank, a chain and a freewheel or cassette depending on what the bike has. getting to 1:1 is where the bike needs to be for it to really work for him.
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Old 02-04-20, 11:33 AM
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I might suggest going to a compact crank and wider range FW in back- an FSA Vero can be had for $85 on Amazon and takes a square taper bb you can nerd out on the Sheldon Brown gear calculator to see the difference of the various configurations compact versus triple

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Old 02-04-20, 12:15 PM
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Originally Posted by non-fixie
Don't know about that hill or the rider, but there is still some room for a fair bit of improvement within the current set-up. It can handle a 38T inner chainring and a 28T largest cog without having to change anything else.

Just my 2 cents.
+1
Baby steps.

Now, I have a long cage version of that RD. Available.
Add a Wolftooth Road Link.
Add a wide freewheel, up to 34t.
Swap in a 38t front.

Did Thunder Ridge on it. 12.75 miles, avg 7.75%, plus Charlegmane's 3/8 mile 9% warmup, and those short nasty buggers after the 100k rest stop. If I can, anyone can.

I second the incremental approach.
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Old 02-04-20, 01:18 PM
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Originally Posted by rccardr
All good ideas. Here's another: replace the crankset with an 86 BCD one like an SR Apex (they were made in multiple BCD's, so check) and put on 50/28 rings. No need to change the BB. That FD will suprisingly shift that combination just fine and with a 28 big cog out back you can keep the current RD and wind up with a 1:1 ratio, same as a compact with a 34 and a different RD.

I used that exact combination on my Faema Merckx at the Coppi event inWisconsin last year, worked a charm. And there are LOTS or steeper hills than that in that part of WI!
Definitely another good suggestion. I have an 86BCD Stronglight 99. There are still plenty of 86BCD rings on the Bay.
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Old 02-04-20, 01:30 PM
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Very cool bike

Use a 13-28t freewheel and a longer chain if it needs it first and see where that gets you -- then maybe have that Willow setup for the front as a back up plan
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Old 02-04-20, 01:38 PM
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Is the current DA crank a 130 BCD? Takagi(which I think became Shimano's crank maker) made some Tourney cranks in both 110/74 and 130/86 triples. This is a 130/86. It's a beauty! You maybe could do rccardr's idea and run a 130 big ring. Lots of options.


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Old 02-04-20, 02:38 PM
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Originally Posted by jackbombay
The hill is ~1000', I've not ridden a bike up it, but have driven up it and it is a bit of a bruiser for someone that isn't currently in shape and has a bit of extra weight on him like he does currently. The hill averages %7 for 2.5 miles,

https://www.strava.com/segments/4871894
Thanks for your reply. Just a couple of notes from my - also under-trained and overweight, BTW - experience: I've tried pretty much all of the above, and for me the difference between the 36 gear inches and say 30 is about 20 to 30 yards before I have to get off and walk on a steep hill. On a not-so-steep hill I'll just have to push a little harder. Below 30" I walk as fast as I ride, and both are equally tiresome.

So for my L'Eroica-compliant bikes I have decided that I am not going to bother anymore with awkward-looking MTB or touring cranks and just mount the smallest inner ring that will fit period-correct racing cranks. Many French and Japanese vintage racing cranks will take a 37T (122 BCD) or 38T (130 BCD).
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Old 02-04-20, 02:51 PM
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Originally Posted by rccardr
All good ideas. Here's another: replace the crankset with an 86 BCD one like an SR Apex (they were made in multiple BCD's, so check) and put on 50/28 rings. No need to change the BB. That FD will suprisingly shift that combination just fine and with a 28 big cog out back you can keep the current RD and wind up with a 1:1 ratio, same as a compact with a 34 and a different RD.

I used that exact combination on my Faema Merckx at the Coppi event inWisconsin last year, worked a charm. And there are LOTS or steeper hills than that in that part of WI!
Excellent suggestion. And while looking at Apex cranks, there's one version that I find particularly enticing. This Apex-5 has a 118mm BCD and has the classic 'Record' look while enabling a 36T inner ring. This is a 49/36 combo. Mated with a 14-28 FW it provides a 34" low gear.

If my dreams come true this will be on mrs non-fixie's 2021 L'Eroica ride:

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