Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

User Tag List

Reply
 
Thread Tools Search this Thread
Old 04-02-12, 04:11 PM   #1
Bornco
Senior Member
Thread Starter
 
Join Date: Oct 2011
Bikes:
Posts: 64
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
44 or 46 Tooth Chainring?

Hi,

My wife and I are both high-cadence riders by nature so we prefer small gaps between gears. Current front chainrings are 50, 39, 26. Unless we are going 20 mph or over we are in the 39.

I'm thinking I would like to lower the gearing to a 46 (or 44), 34, 26. I'm hopingthis would let us use the large chainring more often and provide more us with more useful gears in a range where we can use them. My question is this: I have read that Shimano (we have a Tiagra triple) is made for a 12 tooth gap between chainrings. I'd really like to order a 44, but I'm afraid it won't shift as well because of the 10 tooth difference. Going with a smaller gap between chainrings doesn't seem like a problem to me. (I can see how a larger gap could be a problem for upshifts).

The other problem is I'm not sure if the Tiagra would work well with a 46 in which case I may need a Mtb. derailleur of some sort? (Deore?)

Any advice would be much appreciated,

Thanks,

Jack
Bornco is offline   Reply With Quote
Old 04-02-12, 04:48 PM   #2
rdtompki
Senior Member
 
rdtompki's Avatar
 
Join Date: Nov 2008
Location: Hollister, CA
Bikes: Volagi, daVinci Joint Venture
Posts: 3,962
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
How high is high cadence? A 44-11 at 110 rpm only gives you about 34mph. I don't know where you live, but unless it's dead flat there will probably be many times when you would spin out that gear. If you were running a a 12-27 cassette with your current chainrings you could stay in the middle of the cassette where the jumps are quite small.
rdtompki is offline   Reply With Quote
Old 04-02-12, 05:59 PM   #3
merlinextraligh
pan y agua
 
merlinextraligh's Avatar
 
Join Date: Aug 2005
Location: Jacksonville
Bikes: Wilier Zero 7; Merlin Extralight; Co-Motion Robusta; Schwinn Paramount; Motobecane Phantom Cross; Cervelo P2; Motebecane Ti Fly 29er; Calfee Dragonfly Tandem
Posts: 29,135
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
question is the BCD of the 2 outer rings. (bolt circle diameter) It may well be that the 2 outer rings are 130mm, in which case 38 teeth is as low as it goes.
__________________
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
merlinextraligh is offline   Reply With Quote
Old 04-02-12, 06:28 PM   #4
Bornco
Senior Member
Thread Starter
 
Join Date: Oct 2011
Bikes:
Posts: 64
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Merlin, the Bolt Circle Diameter is 110 and I've found some Vuelta rings online that should work, so I think we're good there.

RD, you make a good point about 34 mph being top end. I'd say we generally ride 95 to 105. My wife has had to switch to 130mm cranks due to a knee problem, so that's another reason I'm thinking I want lower gears. I think in most cases I'm good with coasting if we're going over 32 or so, but it's hard to say never having had that gear as a limiter. I think I generally shut it down when we hit 35 or so most of the time anyway. We also have an 8 speed, so the jumps between teeth aren't as close between as they could be. Your post does make me think I want to go with the 46 though.
Bornco is offline   Reply With Quote
Old 04-02-12, 07:57 PM   #5
ChrisB5string
Junior Member
 
ChrisB5string's Avatar
 
Join Date: Sep 2011
Location: Portage Michigan
Bikes: GT Titanium Road Bike, Trek XC bike, Santana Tandem, Surley Fixed, Swobo Commuter
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Bornco,

Having just gone thru this ordeal, I would stay with the 12 tooth difference (46 -34 rings) . I was ready to ready to make a change sort of like you are thinking of ( 54 to 53) but Peter White talked me out out of it... smart man
ChrisB5string is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 05:31 PM.