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-   -   Drivetrain Question: 9sp Cassette vs. 10sp crankset? (http://www.bikeforums.net/touring/934813-drivetrain-question-9sp-cassette-vs-10sp-crankset.html)

mdilthey 02-19-14 09:38 AM

Drivetrain Question: 9sp Cassette vs. 10sp crankset?
 
2 Attachment(s)
I have an unorthodox (but highly functional) setup on my touring rig and I'm looking to either replace my worn stuff with brand new stuff or convert the entire rig. I am not a bike expert but I am trying, so I would really appreciate any advice, and also patience with a willing student.

http://bikeforums.net/attachment.php...hmentid=364926

I like a 2-ring setup, and I don't want to switch to 3 rings. I climb mountains fine. If I'm honest with myself, shifting in the front can be finnicky.

I also use my bar-end shifters set to friction, not index. I like "tuning" the bicycle actively as I ride. This should simplify the 9sp/10sp conversation.

Here's my bike: http://archive.raleighusa.com/archiv...t-townsend-11/

Current:
50/34 10sp crankset, Shimano Sora (Stock, replaced rings once)
Sora front derailleur (Stock)

I did replace a lot in the back:
9sp Cassette
Shimano XT rear derailleur
Shimano XT 9-sp chain


So, the way I see it, I have three options:

1. Buy a Shimano 105 5600/5700/5750 (which?) front crankset and a Shimano Ultegra bottom bracket. This is the "direct upgrade" approach.

2. Get a 10 speed cassette, buy a 5600/5700/5750 (which?) crankset and a 10 speed chain and an Ultegra bottom bracket. I hear the rear derailleur doesn't care about the 9sp/10sp conflict.

3. Is there a 9 speed crankset that will work on my bike?


Final question: I am going with an Ultegra BB for better bearings, seals, etc. Lots of bad weather riding. Any increase in durability or longevity in an Ultegra crankset? I don't care about saving weight.

sstorkel 02-19-14 11:09 AM

I'm not clear: what parts are worn out and must be replaced? Or are you just upgrading because you want to upgrade?

In any event, my guess is that if you're using friction shifting there won't be much of a problem mixing 9- and 10-speed components. Just don't try to run a 9-speed chain if any of your parts are designed for a 10-speed drivetrain. I personally use a 9-speed trekking crank (Shimano FC-M590) with an otherwise 10-speed Ultegra drivetrain. Had to remove one of the spacers from the drive side of the crank to get the chain line to agree with the FD, but once I did that everything worked perfectly.

I, personally, wouldn't worry too much about BB longevity. I've never managed to wear one out. If you're going to be touring in very remote destinations with atrociously bad weather, then it might pay to invest in a Chris King or Phil Wood bottom bracket. Or just carry a spare BB; they don't weigh that much.

fietsbob 02-19-14 11:53 AM

Quote:

3. Is there a 9 speed crankset that will work on my bike?

Again, 'speeds' is a marketing word.. to sell bikes ..

Its a how many cogs number count on the back.. 10 takes a thinner chain than 9,

so thinner chainrings up front with a bit more space around the inner link roller .. wont matter .

so up front you have 2 chainrings older types were a trifle thicker teeth.



Only such as the internal planetary gear cranksets can it theoretically have 'speeds'.
[Own one with 2]

but in reality you are better off expressing that as a ratio and perhaps gear inch number also.

tshelver 02-20-14 04:40 PM

Off topic, but here in the Philippines, Shimano is about the only game in town for good components.
For 2014, Sora and Alivio are 9-speed only, and Deore / XT are 10-speed only, at least if you are buying an MTB groupset (for a touring / trail recumbent build).

So it looks like they are phasing out 8-speed except for really low end stuff, and pushing 10-speed at the top end.

I don't understand the issue with friction versus index shifting.
I bent a derailleur hanger on my recumbent on some broken roads during a century ride, and could tweak the shifting on the fly to get back solid shifts and 7 of the 9 speeds without much hassle.

LeeG 02-20-14 06:10 PM

Quote:

Originally Posted by tshelver (Post 16513139)
So it looks like they are phasing out 8-speed except for really low end stuff, and pushing 10-speed at the top end.
.

But I just got used to 8spd!

mdilthey 02-23-14 01:27 PM

Quote:

Originally Posted by sstorkel (Post 16509112)
I'm not clear: what parts are worn out and must be replaced? Or are you just upgrading because you want to upgrade?

In any event, my guess is that if you're using friction shifting there won't be much of a problem mixing 9- and 10-speed components. Just don't try to run a 9-speed chain if any of your parts are designed for a 10-speed drivetrain. I personally use a 9-speed trekking crank (Shimano FC-M590) with an otherwise 10-speed Ultegra drivetrain. Had to remove one of the spacers from the drive side of the crank to get the chain line to agree with the FD, but once I did that everything worked perfectly.

I, personally, wouldn't worry too much about BB longevity. I've never managed to wear one out. If you're going to be touring in very remote destinations with atrociously bad weather, then it might pay to invest in a Chris King or Phil Wood bottom bracket. Or just carry a spare BB; they don't weigh that much.


I do tour in atrociously bad weather all the time, and I have managed to hear a bit of a rub in my bottom bracket after about 7 or 8,000 miles of use. So, for $25 or whatever, getting an Ultegra BB seems like a good investment that I can carry over to a new frame (since the frame is likely the next thing to die on my bike).

I talked more with my mechanic and it looks like the 10sp chainrings will take a 9sp chain, so I think Option 1 is the path.

Half of this is replacing parts that need replacing, but half of it is upgrading. I like a bike that really runs.


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