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Sparky
Joined: 08 Dec 2003
Posts: 19083
Location: PDX5/31/19 4:41 PM |
Campy UT chainset/ring options?
I have both Chorus 10speed 39/5# and 11s 34/50 chainsets. I want to change out either the big or smaller ring to a setup with 3ish teeth difference. Like to keep one of the rings and only buy one more.
34-39, keeping the 34. or on the bigger BC keep the 39 and change the 5# for a 42t.
What year have the one threaded bolt chainring? Do the 10s cranks use concentric BC [I don't think the 11s do].
If you know Campy, I assume you can see what I need to know.
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dfcas
Joined: 11 Jan 2004
Posts: 2815
Location: hillbilly heaven5/31/19 6:20 PM |
You might look at specialties TA chainrings. Peter White cycles is a distributor and has a listing that may help you get thru the weeds.
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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5101
Location: Nashua, NH6/1/19 5:48 AM |
One problem that you're going to run into is that all of the sizes you mention are
inner
chainrings, which means that they don't have shift pins or ramps. Consequently, even if they fit and the spacing between the rings is OK, it's going to shift like crap.
Both the 10 and 11 speed chainrings have the 5th bolt offset by a couple millimeters, so they're not compatible with true 110mm chainrings from other brands. You can only use Campy rings. My 11-speed
Last edited by Brian Nystrom on 6/1/19 9:54 AM; edited 1 time in total
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Sparky
Joined: 08 Dec 2003
Posts: 19083
Location: PDX6/1/19 9:19 AM |
For single rear cog, only manual occasional changes, so ramp/pin thing non issue. Probably would be even with a FD with less than 10 T diff anyhow. Like shifting up the 42 to the 52 on a 5 speed pretty much, IF I was going to use a DR.
There is a 42T 135 middle from a triple, but with 3 teeth difference not sure how much help it would be anyway.
I have it down to a Stronlight 7075-T6 CT2 that should work. But Campy is a lot less simple than SH year to year on the rings.
From what I gathered, the compact it turns out is 110/112 BCD, the mount behind the arm being 112BCD, the other 4 110. So challenge there...
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dfcas
Joined: 11 Jan 2004
Posts: 2815
Location: hillbilly heaven6/1/19 11:29 AM |
I think you can file the 112 bolt hole and allow a basic 110 to fit if memory serves me correctly.
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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5101
Location: Nashua, NH6/1/19 12:40 PM |
There may be a recess in the chainring, too. Unfortunately, I don't have my Campy Crank handy.
There were also multiple versions of the cranks with different bolt types and chainring offsets, though I think the latter is only an issue for outer rings.
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Sparky
Joined: 08 Dec 2003
Posts: 19083
Location: PDX6/1/19 8:13 PM |
I saw both that some use a behind the crank arm spacer, and lot of folk use a dremel to make it work on that 112 BCD mount.
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