Author Topic: Touring crankset  (Read 6928 times)

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Offline RussSeaton

Re: Touring crankset
« Reply #15 on: June 25, 2013, 03:36:13 pm »
I wholeheartedly endorse using mountain bike triple cranksets on touring bikes.  The 44-32-22 possible chainrings make lots of sense combined with the 11-32 or 11-34 9 or 10 speed cassettes available today.  More high gears than you need and low enough low gears.  Great.  But the person starting this thread already owns a Sora crankset and bottom bracket with 130mm bcd outer and middle rings and 74mm bcd inner ring.  So its cheaper and easier to just change the chainrings than to buy and install a new crankset and maybe bottom bracket too.  Putting a 24 tooth inner ring on his current crankset gets him a low of 24x32.  I toured Europe using that low gear so its low enough.  Cost wise he would be best to just replace the inner chainring with a 24 tooth and leave the 52 and 42 alone.  Just ride in the 42 and 24 rings all the time.  He has bar end shifters so he can shift anything fine.  If he wants to get crazy he could buy a new cassette for $34 from Nashbar and get 11-34 9 speed cassette.  Little bit lower gearing.  Not worth the money but...

Nashbar has Shimano XT cranksets in 44-32-22 for $200.  And a Race Face crankset in 44-32-22 with bottom bracket for $100.  So if he goes low cost he can end up with a mountain bike triple crankset for only about $30 more than replacing the chainrings  Worth it?

Offline dkoloko

Re: Touring crankset
« Reply #16 on: June 26, 2013, 08:54:18 am »
If it were me, I would invest in a mountain bike compact triple crank set and the tools to do the job.  It sounds like the crank would be more that you want to budget, but the tools could be cheaper than what the dealer would charge you to do things.

Why are you advising the author to throw money in the toilet?  Your advice is very expensive compared to changing the chain rings.  The mountain bike triple you recommend can get down to a 22 tooth inner ring.  He currently has a road triple crankset with 130mm bcd for the outer and middle positions and 74mm bcd for the inner ring.  He can put a 24 tooth ring on his current crankset.  There is so little difference between a 22 and 24 inner ring that its not worth talking about. 

I previously advised that the most economically sensible choice is to just change rings, so we agree on that. However, you error in dismissing difference between 22 and 24 ring as "not worth talking about". It is not the two tooth difference, but the percentage difference in gear inches that is determinative. It is significant enough to determine choice.

Offline staehpj1

Re: Touring crankset
« Reply #17 on: June 26, 2013, 09:30:28 am »
I previously advised that the most economically sensible choice is to just change rings, so we agree on that. However, you error in dismissing difference between 22 and 24 ring as "not worth talking about". It is not the two tooth difference, but the percentage difference in gear inches that is determinative. It is significant enough to determine choice.

Yes a 12% change in gearing is definitely significant.  It is roughly comparable to the difference of shifting from the 30 to the 34 on the rear cluster.  So it basically adds the equivalent of one more gear lower. 

Offline RussSeaton

Re: Touring crankset
« Reply #18 on: June 26, 2013, 07:41:19 pm »
The person has a 11-32 cassette.  A 22x32 low gear is 18.2 gear inches.  A 24x32 low gear is 19.9 gear inches.  If you think you can tell a 1.7 gear inch difference in a gear, you're living in a fantasy world.  Yes the percentage difference is important.  But you somehow forget it depends on what number its a percent of.  I get 8.3% difference between 22 and 24.  8.3% difference of 20 gear inches is about 1.7 gear inches.  8.3% of 100 gear inches is 8.3 gear inches.  It depends on what gear you are talking about.  Big difference between small gears and large gears.  Have you ever thought that is why the small cogs on a cassette change by one tooth.  While the large cogs change by 3 or 4 teeth.

Offline mbattisti

Re: Touring crankset
« Reply #19 on: June 26, 2013, 10:03:34 pm »
I second paddleboy's advice, just swapping the smallest chainring for a 24.  the 24 to 42 jump was no problem on my wife's and my fully loaded tandem, which took us XC a few years ago.  I may suggest adding a n-gear jump stop to prevent the chain from dropping off that little gear.

Offline latifb

Re: Touring crankset
« Reply #20 on: June 27, 2013, 12:27:58 pm »
In my quest to find the best direction for me to go to get the gearing I think would be best a new question has arose which has been alluded to already.
The question is about the importance of ramps and pins for the outer and middle chainrings. I did talk with the mechanic at the LBS I purchased my Salsa from and all the single replacement rings he could find did not have ramps and pins which he thought would lead to poorer shifting even with my friction front derailleur setup. He admittedly wasn't experienced at setting up touring bikes.
So what are folks opinions on the importance of ramps and pins?
Thanks again for all the input so far. This newbie has a lot to learn.

Offline RussSeaton

Re: Touring crankset
« Reply #21 on: June 27, 2013, 02:38:31 pm »
Ramps and pins on the chainrings are good.  They help shifting.  Essential, no.  Helpful, yes.  You have a nine speed 11-32 cassette.  I suspect you will ride most of the time on the middle or outer ring and do all shifting with the rear derailleur.  Shift the front rarely.  So you could easily do without ramps and pins on the chainrings.  They help shifting but they cost more.  Your choice.

Offline latifb

Re: Touring crankset
« Reply #22 on: June 27, 2013, 06:54:12 pm »
Thanks Russ, you got it right about spending most of my time on the middle, and a much smaller time on the front although with a smaller big ring I'm hoping to be able to use that ring much more. I do ride unloaded on fun rides quite a lot. Whatever I finally decide to do you've all been a great help.

Offline Old Guy New Hobby

Re: Touring crankset
« Reply #23 on: June 27, 2013, 07:59:25 pm »
Quote
The person has a 11-32 cassette.  A 22x32 low gear is 18.2 gear inches.  A 24x32 low gear is 19.9 gear inches.  If you think you can tell a 1.7 gear inch difference in a gear, you're living in a fantasy world.

My granny gear is 17.9 gear inches. There are times when I'm glad to have it. It all depends on what you want.

Offline zerodish

Re: Touring crankset
« Reply #24 on: June 29, 2013, 08:12:04 am »
 Santana tandems makes a set they call their stump puller gears the are 24 38 48 Santana is the only company I trust to make a 38 tooth http://www.flickr.com/photos/63373992@N07/7111011835/in/photolist-bQnN5k-4Cs4Yb-4Cs4TN-4CiTE2-4CiTyT-4CiTJz-4CiTp8-4Cob8h-6hkcQA-bPDQoK-ayQuPB-bytiMq-3YMB56-9WGd8Y-6hgcLZ-6hkoNS-3dhDY8-bRpekZ-5EYta3-3VUgXh-jmoDY-jmoEV cog for a 130 mm bolt circle there is not enough metal to prevent it from breaking.

Offline latifb

Re: Touring crankset
« Reply #25 on: June 29, 2013, 03:34:02 pm »
I discovered something this morning that may have an effect on what I choose to do. I've assumed all along that the factory advertised spec for my Salsa is 52/42/30. When I talked to my LBS mechanic the other day he was looking closely at the big ring and noticed it was stamped 50t. Interesting. This morning I put on my magnifiers and counted the teeth on all the rings and found 50/39/30 which is the spec for the previous years model and does make much more sense. I still need lower gears but  just swapping the 30 for a 24 is the simplest way to go. I can only go down to a 38 on the middle with the 130bcd so that swap makes little sense. The 50 is still  too big but I spend so little time on that ring that maybe I can just let that go. 24 to 39 still seems like a big jump but much less than the 24 to 42 possibility.

Offline dkoloko

Re: Touring crankset
« Reply #26 on: June 30, 2013, 07:17:40 am »
24 to 39 still seems like a big jump but much less than the 24 to 42 possibility.

I shift from 24 to 49; no problem.