Go Back  Bike Forums > Bike Forums > Tandem Cycling
Reload this Page >

IPS Questions

Notices
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!

IPS Questions

Old 05-17-21, 09:24 AM
  #1  
strock 
Senior Member
Thread Starter
 
Join Date: Aug 2005
Location: Hudson Valley, NY
Posts: 254
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
IPS Questions

My wife and I recently acquired a used Terratrike Rover Tandem. The trike is equipped with an Independent Pedaling System (IPS). The captain's crank has 170mm arms, and the stoker's crank has 145mm arms. The 145s work well for my wife, but the 170s are long for me, and I'm finding them a bit hard on the knees. (I run 130s on most of my recumbents to keep knee flexion relatively low.) So, I want to go shorter. I see two options. One would be to use crank shorteners. The other would be to replace the current captain's crankset with a non-IPS crankset. The advantage of the second option is that it would enable me to run a smaller chainring, effectively lowering the gearing on the bike, which is too high for some of the hills around here. The disadvantage is that the captain, as I understand it, would lose the ability to coast while the stoker was pedaling, although the stoker would retain the ability to coast while the captain was pedaling. Is that right? If I do go with shorter cranks and a smaller chainring, I'm assuming that my cadence would increase. This would require the stoker to increase her cadence, too, quite possibly beyond her comfort level. Is there a way to compensate for that, possibly by changing out the timing ring on the stoker's crank? If so, would I need to go larger or smaller? (I'm guessing larger.) Thanks in advance for any and all advice.
__________________
Steve
strock is offline  
Old 05-17-21, 12:23 PM
  #2  
Leisesturm
Senior Member
 
Join Date: Jul 2005
Posts: 5,968
Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 2473 Post(s)
Liked 722 Times in 513 Posts
IPS in general gives me a headache, but I can usually work it out with some coffee to help. Your system looks like your chainring affects only your gearing. The Stokers chainring affects both of yours' gears. Pretty similar to the way it is on 'conventional' tandem drive-trains. On your system your 'timing rings' are not independent. It gets to be a mess changing things around. But since you aren't in a fixed Captain/Stoker link it could probably work.
I'll admit a bias against IPS, even simple systems like on the Terratrike. That said, shortening your cranks with crank shorteners allows you to preserve IPS on your trike. I don't know if you can get to the 130's but at least into the 140's. I don't think it's worth it to do more. I wouldn't, however, argue strenuously against getting some conventional used cranks from a bike co-op and forego IPS altogether. Has it been your experience that your cadence increases when/if you shorten your cranks and/or lower the gearing? I personally don't think it does. What I see is that your cadence stays the same and you go slower. And that's fine. But if you ride with others it may start to seem like you are always chasing them.
Leisesturm is offline  
Old 05-21-21, 02:16 PM
  #3  
strock 
Senior Member
Thread Starter
 
Join Date: Aug 2005
Location: Hudson Valley, NY
Posts: 254
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
Originally Posted by Leisesturm
Has it been your experience that your cadence increases when/if you shorten your cranks and/or lower the gearing? I personally don't think it does. What I see is that your cadence stays the same and you go slower. And that's fine. But if you ride with others it may start to seem like you are always chasing them.
It has been my experience that cadence increases when I use shorter cranks and/or lower gearing. I just spin the smaller circle faster. Anyway, I've swapped out the 170 IPS captain's crankset for a set of 130s with a 22t small ring. Feels so much better on the knees and climbs so much better when I'm on the trike by myself. Not sure what's gonna happen when I add my wife/stoker to the mix. It might not be pretty.
__________________
Steve
strock is offline  
Likes For strock:
Old 05-26-21, 01:03 PM
  #4  
Ross200
Junior Member
 
Join Date: Feb 2019
Posts: 154
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 57 Post(s)
Liked 44 Times in 34 Posts
You might look into this:

Short Bicycle Cranks
Ross200 is offline  
Old 05-28-21, 01:40 PM
  #5  
strock 
Senior Member
Thread Starter
 
Join Date: Aug 2005
Location: Hudson Valley, NY
Posts: 254
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
Originally Posted by Ross200
You might look into this:

Short Bicycle Cranks
Thanks for the tip. I've ordered short cranks from Bikesmithdesign in the past.
__________________
Steve
strock is offline  
Old 10-27-21, 10:33 AM
  #6  
WesleyEng.com
Junior Member
 
Join Date: Jun 2013
Location: NYC
Posts: 19

Bikes: Pacific Dualie

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked 0 Times in 0 Posts
Not sure if I should start a new thread for this but how do I get IPS on my tandem?
WesleyEng.com is offline  
Old 10-28-21, 03:53 PM
  #7  
LV2TNDM
Senior Member
 
Join Date: Apr 2005
Location: Northern CA
Posts: 731

Bikes: Cannondale tandems: '92 Road, '97 Mtn. Mongoose 10.9 Ti, Kelly Deluxe, Tommaso Chorus, Cdale MT2000, Schwinn Deluxe Cruiser, Torker Unicycle, among others.

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 275 Post(s)
Liked 201 Times in 127 Posts
Freedom Rotation Crankset

Originally Posted by WesleyEng.com
Not sure if I should start a new thread for this but how do I get IPS on my tandem?
Normally, I'd say you can't. But then I remember this couple has the subject crankset on their carbon full suspension:
(skip to 1:30 for cranks)
I've never looked into the cranks, but it seems like a pretty straightforward retrofit.
A reseller:
https://store.mscbikes.com.au/produc...et-for-tandems
Good luck
LV2TNDM is offline  
Old 10-28-21, 04:11 PM
  #8  
WesleyEng.com
Junior Member
 
Join Date: Jun 2013
Location: NYC
Posts: 19

Bikes: Pacific Dualie

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked 0 Times in 0 Posts
Originally Posted by LV2TNDM
Normally, I'd say you can't. But then I remember this couple has the subject crankset on their carbon full suspension:
https://www.youtube.com/watch?v=njmNDuA3TCU
(skip to 1:30 for cranks)
I've never looked into the cranks, but it seems like a pretty straightforward retrofit.
A reseller:
https://store.mscbikes.com.au/produc...et-for-tandems
Good luck

Literally blurted out HOLY COW when I saw the price. I can almost buy 2 of my tandems for that price. Maybe when I’m really old and broken I’ll get this so the younger missus can pedal for me
WesleyEng.com is offline  
Old 10-29-21, 04:09 PM
  #9  
unikid
Junior Member
 
Join Date: Feb 2018
Posts: 179
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 47 Post(s)
Liked 25 Times in 23 Posts
Originally Posted by WesleyEng.com
Literally blurted out HOLY COW when I saw the price. I can almost buy 2 of my tandems for that price. Maybe when I’m really old and broken I’ll get this so the younger missus can pedal for me
If you have your heart set on getting IPS then you need to be ready to pay some money to get it. Here is why:
  1. Most IPS systems use a right-side sync chain design. Your Dualie (like most tandems) has the sync chain setup on the left side. So at minimum you are going to have to convert your front crankset to a right-side drive before any IPS system will work.
  2. Your Dualie (like most tandems) also has a triple crankset in the rear which requires a more complex/expensive solution than if you just had a single drive system. However if you are willing to give up the triple in the rear then you might be able to reduce your cost.
To set up your stoker for IPS with a single chainring crank, here is one option I found:To set up your stoker for IPS with a triple chainring crank here are 2 options I found:To set up the captain for IPS, here is one option I found (note: you don't need this unless you also want to be able to coast while the stoker continues pedaling):There are likely other options out there. I see that Bike Friday and a few other tandem bike makers also offer an IPS system. Just not sure if they sell theirs separately or how much they cost.

To get a taste of IPS another option you could take is to try to find somebody who owns or is selling a Greenline tandem. Or a Greenzone folding tandem.
Both of these tandems (no longer made) came with a basic IPS system (front and rear) already on it.
They apparently sold quite a few of these since I regularly see these pop up on Craigslist or Offerup. At least in my area (SoCal).
Note: these only have the single chainring in back, plus they don't appear to have as easily replaceable/customizable chainrings like the systems above appear to have.

Here are some links to the Greenline tandem plus one for sale near me and one for sale closer to you as an example:
x GreenLine Tandem 7 Spd Shimano Tourney Independent Pedaling Yellow (check out image 5 of 6 for a close up of the cranks)
https://inlandempire.craigslist.org/...399637983.html
https://www.facebook.com/marketplace/item/6259545984086604/?ref=search&referral_code=marketplace_search&referral_story_type=post

Here are some links to the Greenzone folding tandem:
(he shows the IPS system directly)
https://offerup.com/item/detail/225691961
unikid is offline  
Likes For unikid:
Old 11-01-21, 11:33 AM
  #10  
unikid
Junior Member
 
Join Date: Feb 2018
Posts: 179
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 47 Post(s)
Liked 25 Times in 23 Posts
I checked with Greenzone since they are still in business. Although they don't carry the tandems anymore they still have a few sets of the IPS cranks.

They work with standard square taper bottom bracket. They offered to sell me 2 IPS cranks (right side - front and back) for $99. This price does not include left side crank arms.

To get the complete set including matching left side crank arms it would be $149 shipped. You can reach out to: alan@greenzonebikes.com.
unikid is offline  
Likes For unikid:

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.