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


Go Back   > >

Folding Bikes Discuss the unique features and issues of folding bikes. Also a great place to learn what folding bike will work best for your needs.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 07-16-17, 07:32 PM   #1
Estuche
Senior Member
Thread Starter
 
Join Date: Apr 2010
Bikes:
Posts: 83
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Which has less pedal bob when standing, Birdy or Moulton??

Which has less pedal bob when standing to pedal, Birdy or Moulton?? Any adjustments or part replacement to either bike to make it less pronounced?

Ps: I know rider technique matters as well, but this is one of those "everything else being equal"

Last edited by Estuche; 07-16-17 at 07:42 PM.
Estuche is offline   Reply With Quote
Old 07-16-17, 08:07 PM   #2
jur
Senior Member
 
Join Date: May 2005
Bikes:
Posts: 7,211
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 192 Post(s)
I would say the Birdy. But the Moulton is adjustable.
jur is offline   Reply With Quote
Old 07-17-17, 08:22 AM   #3
Rick Imby
Senior Member
 
Join Date: Sep 2015
Bikes:
Posts: 397
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
The design of the Moulton is very old and does not take into account pedal induced BOB. The Birdy does. As the chain pull forward on the rear hub the Moulton will move. The Birdy is designed to have the rear suspension pivot inline with the chain. Nearly no pedal induced BOB. However your pedaling motion while standing will cause both to bob...

The mountain bike world discovered this a long time ago and has moved the rear suspension pivot (on single pivots anyway) inline with the chain.


I have never ridden either of these bikes but I have had over a dozen different full suspension mountain bikes.
Rick Imby is offline   Reply With Quote
Old 07-17-17, 10:43 AM   #4
berlinonaut
Senior Member
 
Join Date: Mar 2016
Bikes:
Posts: 105
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 59 Post(s)
I'd tend to say the Moulton but am sure it depends. The Moulton's rear suspension is pretty stiff, therefor there is not much bob to be discovered there. The front-suspension is a different story - I could imagine that the Birdy could be better here but have not enough experience with the Bridy to judge on that. On the other hand "the Moulton" does not exist as there are various Models (even more over the years) using different suspensions (front AND rear) and furthermore i.e. for the front of the current TSRs there are springs of different strengths available plus the suspension is adjustable (and a lot of people seem unable to adjust it correctly). I am still amazed on how well the suspension on my TSR performs (after proper adjustment) while at the same time it is a very fast and very stiff ride. My last ride on a Birdy was a couple of years ago (so memory may lead me wrong) and while I liked the ride on the Birdy, too I'd consider the Moulton more perfomance-orientated, even with the entry level model TSR. Never rode one of the more expensive models.
berlinonaut is offline   Reply With Quote
Old 07-17-17, 05:17 PM   #5
jur
Senior Member
 
Join Date: May 2005
Bikes:
Posts: 7,211
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 192 Post(s)
The question was bob when standing. I have puzzled and analysed a lot over front suspension bob while standing, and have come to the conclusion for the front at least it doesn't matter much as it doesn't waste energy. In fact I think the opposite, it saves a bit of energy compared to no front suspension. I can elaborate if anyone is interested.

The Moulton front when adjusted very compliant will bob a lot more than the Birdy, but it can be adjusted.

Rear suspension for both is pretty stiff so very little pedal-induced bob, not worth obsessing about. Both have their rear pivots close to the bottom bracket.
jur is offline   Reply With Quote
Old 07-19-17, 01:37 AM   #6
Sangetsu
Senior Member
 
Sangetsu's Avatar
 
Join Date: Jun 2008
Location: 東京都
Bikes:
Posts: 684
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 296 Post(s)
It also depends on your pedals and your technique. You can bounce all over a road bike if you don't know how to pedal in circles. It's hard to avoid when standing on the pedals, but clipless pedals and technique help. It's a bigger problem when riding while seated, at faster speeds and higher cadences.

The Birdy rear suspension is just a piece of elastomer, a plastic/rubber spring, with no compression or rebound damping. If you shop around you can find air or hydraulic suspension for the Birdy with damping, but these are hard to find, and a little expensive, usually about $250. These reduce the bobbing, but at the cost of some added weight. The front suspension on the Birdy is a work of genius, and doesn't do much to contribute to bouncing and bobbing, and there is absolutely no brake dive.
Sangetsu is offline   Reply With Quote
Old 07-19-17, 08:43 PM   #7
pinholecam
Senior Member
 
Join Date: Jan 2016
Bikes:
Posts: 184
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
I have the Moulton TSR, but I don't stand to pedal as I can't even stand the bit of bobbing with seated climbing.
The front suspension is adjustable, so it can be optimized somewhat to have less bobbing while giving reasonable compliance for the suspension.
The rear elastomer is not adjustable, but its rather hard, so there is less bobbing from it.
All said, there will be bobbing during climbing unless on easy enough gears.
Easy gears may not be at all possible if riding in a group and trying no be ahead or not getting dropped.


I have only tried the Birdy on a few occasions.
The front and rear elastomers can be changed to very hard ones to almost eliminate bobbing.
However, I found that the bike felt very harsh with such an option and defeats the purpose of using it.
pinholecam is online now   Reply With Quote
Old 07-20-17, 10:43 AM   #8
Steamer
Senior Member
 
Steamer's Avatar
 
Join Date: Nov 2008
Location: high ground
Bikes:
Posts: 842
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 37 Post(s)
Quote:
Originally Posted by Rick Imby View Post
The design of the Moulton is very old and does not take into account pedal induced BOB. The Birdy does. As the chain pull forward on the rear hub the Moulton will move. The Birdy is designed to have the rear suspension pivot inline with the chain. Nearly no pedal induced BOB. However your pedaling motion while standing will cause both to bob...

The mountain bike world discovered this a long time ago and has moved the rear suspension pivot (on single pivots anyway) inline with the chain.


I have never ridden either of these bikes but I have had over a dozen different full suspension mountain bikes.


While I think that was true in the past, most (all?) current Moulton models have a unified rear triangle which includes the BB. Pedaling forces cannot actuate the rear suspension.
Steamer is online now   Reply With Quote
Old 07-20-17, 06:17 PM   #9
jur
Senior Member
 
Join Date: May 2005
Bikes:
Posts: 7,211
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 192 Post(s)
Quote:
Originally Posted by Steamer View Post
While I think that was true in the past, most (all?) current Moulton models have a unified rear triangle which includes the BB. Pedaling forces cannot actuate the rear suspension.
Not directly, no. If you consider an isolated torque on the pedals, then the suspension is not actuated. However since the rider is also connected to the rest of the frame via saddle and handlebars, the pedaling counter-torque on the saddle and handlebars does actuate the suspension. It is an improvement on the older design where the BB was not a part of the moving rear triangle, though.
jur is offline   Reply With Quote
Old 07-20-17, 06:32 PM   #10
BruceMetras
Senior Member
 
Join Date: Aug 2005
Location: San Rafael, California
Bikes:
Posts: 2,000
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 69 Post(s)
My New Series Moulton has an easy to use 'suspension lock out' device for the front end... I never use it .. I like a compliant front end, but it is there just incase the front bobbing while hammering uphills bothers some..
BruceMetras 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 07:49 PM.


 
  • Ask a Question
    get answers from real people!
Click to start entering your question.
I HAVE A QUESTION