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New Crankset Woes, Chainring Sizes, Back to Square Taper

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New Crankset Woes, Chainring Sizes, Back to Square Taper

Old 07-18-09, 01:13 AM
  #1  
johnknappcc
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New Crankset Woes, Chainring Sizes, Back to Square Taper

I installed my new DA triple 53-39-30 crankset with matching DA Octalink bottom bracket, and took it for a spin (26 miles) last night.

I found pretty quickly that I couldn't get the gear ratio I like without cross chaining the 39 with the 12-13 or the 53 with the 19-21. I'm running a 12-21 9-speed DA cassette.

So, tonight I reinstalled the old cup and cone JIS sq taper BB and biopace triple 50-44-28 crankset. This front gearing is much more suitable to my cadence and speed, mostly in the 44 and the middle of my cassette, and sometimes in the 50 just low to the middle.

I have to say I like the weight reduction of the DA cranks, but I'm going to look for a new crank or just (round) chainrings.

My question, is there a suitable JIS sqare taper crank, with the same quality level as DA/Ultegra in a similar gearing as my current 44/50, so should I just get some Sugino or Surly chainrings and use my current crank (maybe swapping out the spacers for smaller ones to more match 9-speed chainring spaces)?

BTW, my current triple is 110/74 BCD. And, I know that I will be ditching the 28 for something more like a 32 . . .
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Old 07-18-09, 06:12 AM
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The tough part is finding 9 spd. compatible and the only 9 spd. crank I found, without going to QBP, was the Nashbar ISIS Trekking crank - http://www.nashbar.com/bikes/Product..._200276_200376

28/38/48 in 110/74 BCD, @ $90 plus $25 for a b-bracket, which means it's not breaking the bank if you swap out the middle down to a 34 or so and get the range of a standard road compact double. Other potential issue is it's ISIS b-bracket, which not everyone is enamored with, though I also read good (or not terrible) comments about them.

There are some nice Sugino and TruVativ as well as Stronglight cranks, at reasonable cost for square taper, but none I've found that are 9 spd. compatable. In general, once 9 spd. was introduced, the bottom brackets all went to ISIS, Shimano's ISIS version, Octalink, or the newer external bearing systems. Some of these b-bracket designs are very nice and I just did an adjustment of an FSA Mega-XO system, that was wonderful and easy to adjust (clean and tighten) and work on. So now we wait and see if TruVative, Sugino etc.. modify any of their product line for 9 spd.

Steve B.
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Old 07-18-09, 07:11 AM
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Is there a disincentive to getting new rings for your DA crank? I've not been in the market, so I don't know if they're hard to find. I would think it'd be pretty straightforward ,and possibly even revenue-neutral, once you sell the originals.
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Old 07-18-09, 07:32 AM
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The 9-speed D/A triple was unusual in that the 30T granny ring was bolted to tabs on the specific 39T middle chainring with a nonstandard 90-something mm bolt circle. 30T is the smallest that will fit. It did not have a standard 74 mm bolt circle machined into the crank arms themselves.

Therefore, you can not keep it a Dura Ace triple if you replace the OEM 39T middle ring.

If you want a triple with more options, get an Ultegra 6500. It has the common 130/74 mm bolt circles and there are a lot of gearing possibilities. It uses the same triple 118 mm Octalink bb as the D/A.

BTW, have you calculated the gear table for your current gearing? The 39x13 combination is 81 gear-inches and the 39x12 is 88 gear-inches. The 53x17 is 79.5 gear-inches and the 53x16 is 89 gear-inches so you don't have to cross chain in the 39T ring to get the same ratios. The 53 ring will provide them with outcross chaining.
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Old 07-18-09, 07:54 AM
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Sounds like a failure to plan your gearing before buying and installing new parts. FWIW, I used triples for several years for the Colorado mountains. I used a 53/39/28 with a 12-25 (10 speed) cassette.

Using the middle ring with the is of second cog is NOT cross-chaining. The middle ring on a triple is within 1-2mm of the same postion as the big ring on a double and I treat it the same way. I never had a problem using the middle ring and smallest cog.

Your 50/44/28 is a real oddball, with extremely little difference between the 50 and 44. I prefer chainrings that have relatively uniform spacing, like a 53/39/30 or 53/39/28. After swithcing between chaintings, the same 2-cog shift is needed arrive at the next lower or higher ratio in a uniform progression.

Your 28/21 is not a very low gear. You could get that with a common 50/34 compact crank and a 12-25 cassette, but a 12-25 9 speed would lack the 16 and 18T cogs that you have now. I assume that you ride enough flats that the 18T is considered important.

FWIW, a 50/34 with a 12-25 11 speed cassette would have the 16 and 18.
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Old 07-18-09, 08:20 AM
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Originally Posted by DaveSSS View Post
Your 50/44/28 is a real oddball, with extremely little difference between the 50 and 44. I prefer chainrings that have relatively uniform spacing, like a 53/39/30 or 53/39/28. After swithcing between chaintings, the same 2-cog shift is needed arrive at the next lower or higher ratio in a uniform progression.
That was half-step plus granny gearing and was common in the era of 5 and 6-speed freewheels when the gaps between the cogs were very big if it had a reasonably wide-range. The two chainrings split the proportional difference between the cogs and provided a series of closer steps. Done right, there were nearly no duplicate gears. The downside was that every second shift required shifting both derailleurs.

Originally Posted by DaveSSS View Post
FWIW, a 50/34 with a 12-25 11 speed cassette would have the 16 and 18.
So do Campy's 13x26 10-speed and Shimano's 13x23 9-speed and 13x25 10-speed cassettes. Personally, I insist that a road cassette have a 16T cog but find the 18T of limited use. The gap from 17 to 19 isn't that bad.
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Old 07-18-09, 09:48 AM
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Originally Posted by tellyho View Post
Is there a disincentive to getting new rings for your DA crank? I've not been in the market, so I don't know if they're hard to find. I would think it'd be pretty straightforward ,and possibly even revenue-neutral, once you sell the originals.
Yeah, they don't interchange on the DA one because the granny is bolted in to middle and not the crank itself. It uses a 92mm BCD.

Originally Posted by HillRider View Post
If you want a triple with more options, get an Ultegra 6500. It has the common 130/74 mm bolt circles and there are a lot of gearing possibilities. It uses the same triple 118 mm Octalink bb as the D/A.

BTW, have you calculated the gear table for your current gearing? The 39x13 combination is 81 gear-inches and the 39x12 is 88 gear-inches. The 53x17 is 79.5 gear-inches and the 53x16 is 89 gear-inches so you don't have to cross chain in the 39T ring to get the same ratios. The 53 ring will provide them with outcross chaining.
I'm thinking the Ultegra is the way to go, maybe along the lines of a 52/42/30. I'm going to do the gear calculator today.

Originally Posted by DaveSSS View Post
Sounds like a failure to plan your gearing before buying and installing new parts.
True, but it was time sensitive, got the brand new DA crank and BB for 175 shipped. If I sold it right now with 26 miles on it, I could probably still make money.

Originally Posted by DaveSSS View Post
Using the middle ring with the is of second cog is NOT cross-chaining. The middle ring on a triple is within 1-2mm of the same postion as the big ring on a double and I treat it the same way. I never had a problem using the middle ring and smallest cog.
From Shimano's instructions, it isn't a recommended gearing. The chain looked pretty crossed, didn't seem like a performance penalty, just way more crooked than I would like.

Originally Posted by DaveSSS View Post
Your 50/44/28 is a real oddball, with extremely little difference between the 50 and 44.
It is an oddball, but like HillRider says, it was originally used with a 5 speed freewheel on my touring bike. I always used the outer (50) with my old freewheel (approx 14-28 or something like that) but when I did the 27' -> 700C conversion, I got a good deal on a 9 speed DA cassette (12-21) and liked the gearing choices in the 44 a bit more.

Originally Posted by DaveSSS View Post
I assume that you ride enough flats that the 18T is considered important.
True story, Chicago is pretty flat.
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Old 07-18-09, 10:25 AM
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Originally Posted by johnknappcc View Post
I installed my new DA triple 53-39-30 crankset with matching DA Octalink bottom bracket, and took it for a spin (26 miles) last night.

I found pretty quickly that I couldn't get the gear ratio I like without cross chaining the 39 with the 12-13 or the 53 with the 19-21. I'm running a 12-21 9-speed DA cassette.

So, tonight I reinstalled the old cup and cone JIS sq taper BB and biopace triple 50-44-28 crankset. This front gearing is much more suitable to my cadence and speed, mostly in the 44 and the middle of my cassette, and sometimes in the 50 just low to the middle.

I have to say I like the weight reduction of the DA cranks, but I'm going to look for a new crank or just (round) chainrings.

My question, is there a suitable JIS sqare taper crank, with the same quality level as DA/Ultegra in a similar gearing as my current 44/50, so should I just get some Sugino or Surly chainrings and use my current crank (maybe swapping out the spacers for smaller ones to more match 9-speed chainring spaces)?

BTW, my current triple is 110/74 BCD. And, I know that I will be ditching the 28 for something more like a 32 . . .

Don't make this so complicated, just get some new chainrings. I don't think you need to change any spacers for 9 speed chainrings. 44/50 is not oddball. If it works for you, who cares what others use? On flatter terrain I bet it works great. Heck, I use 26/44/48 and I live in very hilly country with a 13-32 7-speed. You could call it half-step, but I only use the half steps when I need them, otherwise I shift normally. I use all 7 cogs in the 44 ring. I find crossover gears to be strange myself, so there you go.

You live in Chicago, you say it's flat. . . you're not racing ...... so what are you concerning yourself with a few grams of crank weight for?
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Old 07-18-09, 05:05 PM
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If you are in Chicago, Lickbike has a wide range of chainrings. Give them a call.
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Old 07-18-09, 05:27 PM
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Originally Posted by chas0039 View Post
If you are in Chicago, Lickbike has a wide range of chainrings. Give them a call.
Yeah, I biked over there today . . . probably pick some up next week.
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