46/33 chainrings on Campy 10 speed?

[edward12]

I'm building up a new Mercian frameset and I have Sugino Alpina cranks, TA 46/33 chainrings, and a 12-29 cassette. I was wondering if anyone could foresee any issues with this gear range - I mean, intuitively, I don't see any problems, but I thought I would tap into the collective wisdom here and double-check.

[cgolvin]

The only potential problem I can imagine is if the frame has a braze-on for the front derailleur. I believe some people have had issues with the FD being low enough for a 46, even resorting to a file. The 29 should not be a problem for a short cage RD.

As to the gearing, only you know the areas you ride and what range you need. It seems to me that your combination will have a lot of overlapping gears.

[Mark McM]

It should probably be fine. But where did you get a Campagnolo 10spd 12-29 cassette? Campagnolo only made 13-29 and 12-30 10spd cassettes.

(As a point of reference, I've used 48/32 and 44/28 Sugino chainrings on a Sugino OX crank with Campagnolo 10spd, and 48/32 TA chainrings on a Rotor crank with Campagnolo 11spd.)

[Mark McM]

Originally Posted by cgolvin

The only potential problem I can imagine is if the frame has a braze-on for the front derailleur. I believe some people have had issues with the FD being low enough for a 46, even resorting to a file. The 29 should not be a problem for a short cage RD.

This is a good point. Modern frames are designed for compact cranks, and have the braze-on lower, but classic era frames will probably be designed for "standard" size cranks, and have the braze-on mounted higher. There are ways to deal with this, including adapters to lower a derailleur on a braze-on tab.

[edward12]

Originally Posted by Mark McM

It should probably be fine. But where did you get a Campagnolo 10spd 12-29 cassette? Campagnolo only made 13-29 and 12-30 10spd cassettes.

(As a point of reference, I've used 48/32 and 44/28 Sugino chainrings on a Sugino OX crank with Campagnolo 10spd, and 48/32 TA chainrings on a Rotor crank with Campagnolo 11spd.)

Thank you for the guidance. I misspoke. It's actually a 13-29 cassette.

[tdh]

There are numerous posts all over the internet that the 13-29 cassette can be used with a short cage Campagnolo rd. I couldn't make it happen. The mid length cage did the trick. But again, some people seem to be able to make it work with the short cage...

[Gabe77]

I have run a TA 46T chainring on a 4 arm Chorus crankset with a matching 2015+ FD. FD shifted perfectly, in fact the lower position opened up a better angle to the cassette and I got a completely trim-free setup across the board.
Problem is that you cant fit a 34- small ring and the small jump upset my upshift/downshift habits so I changed back to compact.
But the 46 front shifting absolutely no issue.

[Flinch]

I went to a triple 10 speed Campy Chorus, and have a 24t ring/30 cassette setup. Works peachy. Had to get the 'triple' (mountain) rear derailleur though. My CSI with a 21 gear-inch climbing gear is happy-happy now.

A 30 Campy cassette? Yep, ordered a Miche 30t cog from BikeInn last year, $7, and dropped one of the Campy cogs, can't remember which, and put the 30 in as top dog.

[zennmotion]

Originally Posted by Mark McM

This is a good point. Modern frames are designed for compact cranks, and have the braze-on lower, but classic era frames will probably be designed for "standard" size cranks, and have the braze-on mounted higher. There are ways to deal with this, including adapters to lower a derailleur on a braze-on tab.

Yep. Even if the front derailleur works OK in the bike stand with a larger than optimal gap to a smaller chain ring, it's a matter of time before the chain will get dropped, at least damaging the frame/paint or worse (injury). Get one of these, I have one, works well (Shimano D/A 7400 front derailleur, Sugino 34-46t crankset).
https://www.fsaproshop.com/products/...illeur-adapter

Threads like this should be banned without pictures. Let's see the Mercian in whatever state it's in! I hope it's BR green. Or another color...

[edward12]

Cool stuff. Fortunately, I don't have to contend with a brazed front derailleur hanger. I'll post pictures as soon as I complete the build.

[rice rocket]

Is 46-13 enough gear for your riding? Or maybe you just plan on freewheeling down hills?

That's equivalent to a 39T big ring with an 11T, or 35T if you go down to a 10T (or 32-9 in Ekar speak).

[edward12]

I intend to use this bike as a sort of an "all-road" bike (it has clearances for 35mm tires, etc.). I think the 46t will suit my needs - I live near the base of the Sierra Nevada mountains and the surrounding foothill areas. So, it's pretty undulating terrain with paved roads in poor condition and quite a bit of mixed surfaces. I'm not really looking for speed on the descents with this bike - BUT I'm keeping my 48t chainring just in case!

[Gabe77]

I was dialling in my perfect gear range on my training bike recently. I worked out I hardly ever used the 50/12 so I'd drop it down to a 46. (running a 50/34 front with 12-25 rear). The experiment didn't work out as I found I did need the 50/12 more than I anticipated and the smaller double-shift jump threw out my shifting habits.
While I couldn't stick a 33 on the small ring the 46/34 combo worked perfectly as far as shifting. You can get an aftermarket 33T for the Ultegra/DA 11spd cranksets mind you but the Campagnolo BCD is just a bit bigger.
For anyone contemplating this watch out for the chaindrop ferrule on TA branded big chainrings - it is too long and digs into the crank arm. I had to remove it to fit the ring. I'm talking the 4-arm post 2015 Chorus.

[NHAero]

Originally Posted by Gabe77

Snip
For anyone contemplating this watch out for the chaindrop ferrule on TA branded big chainrings - it is too long and digs into the crank arm. I had to remove it to fit the ring. I'm talking the 4-arm post 2015 Chorus.

I have encountered this also, and just take a file or Dremel to it as needed to shorten it to fit

[edward12]

I posted pics of the built under another thread. https://forums.thepaceline.net/showt...41#post3372641