Which has less pedal bob when standing, Birdy or Moulton??
12-29-17, 05:07 AM
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The unified rear triangle doesn't make the difference with pedal bob. The pivot location is what is critical. The URT may help with frame stiffness. The other issue in comparing Bob with the birdy and Moulton is the difference in Travel. The significantly longer travel of the birdy suspension will add to the bob.
Pedal induced bob is created when the chain is not pulling directly into the pivot of the rear suspension. The larger the angle the larger the pedal induced bob.
The other factor in Bob is the rider induced bob which comes from the up and down movement of the rider----this adds significantly to pedal induced bob especially with longer travel suspensions.
Pedal induced bob is created when the chain is not pulling directly into the pivot of the rear suspension. The larger the angle the larger the pedal induced bob.
The other factor in Bob is the rider induced bob which comes from the up and down movement of the rider----this adds significantly to pedal induced bob especially with longer travel suspensions.
The unified rear triangle is a concept where all the rear triangle including the bottom bracket is made in a single piece just like on a suspension less bike, the bottom bracket is not part of the main frame (like on the Birdy) but part of the un-suspended rear triangle: the bottom bracket and rear wheel (and both front and rear derailleur) are on one rigid sub-frame so the chain pulling doesn't influence the suspension at all.
The only effect of pedaling on the suspension comes from the cyclist himself mainly when he is pedaling out of the saddle.
Note that not all current Moulton have the unified rear triangle: the AM series (AM GT, AM Speed...) do not have the unified rear triangle, but the Jubilee, Speed, TSR, SST and NS have it (with several variations of it).
The Birdy and Brompton have their bottom bracket part of the main frame with a moving rear arm/triangle.
Now comparing these two bikes with a Moulton is for me unfair because they are both folding bikes and the design of their rear suspension had also to take into account the folding, i.e the rear suspension pivot position wasn't only chosen to optimize the suspension behavior but also the folded size.
This is especially true on the Brompton: moving the rear pivot to the back of the bottom bracket reduced the folded length.
12-30-17, 09:51 AM
#27
Zircon Encrusted Tweezers
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With your explanation for what causes the pedal induced bob, I have the impression that you do not know or understand what the unified rear triangle is.
The unified rear triangle is a concept where all the rear triangle including the bottom bracket is made in a single piece just like on a suspension less bike, the bottom bracket is not part of the main frame (like on the Birdy) but part of the un-suspended rear triangle: the bottom bracket and rear wheel (and both front and rear derailleur) are on one rigid sub-frame so the chain pulling doesn't influence the suspension at all.
The only effect of pedaling on the suspension comes from the cyclist himself mainly when he is pedaling out of the saddle.
Note that not all current Moulton have the unified rear triangle: the AM series (AM GT, AM Speed...) do not have the unified rear triangle, but the Jubilee, Speed, TSR, SST and NS have it (with several variations of it).
The Birdy and Brompton have their bottom bracket part of the main frame with a moving rear arm/triangle.
Now comparing these two bikes with a Moulton is for me unfair because they are both folding bikes and the design of their rear suspension had also to take into account the folding, i.e the rear suspension pivot position wasn't only chosen to optimize the suspension behavior but also the folded size.
This is especially true on the Brompton: moving the rear pivot to the back of the bottom bracket reduced the folded length.
The unified rear triangle is a concept where all the rear triangle including the bottom bracket is made in a single piece just like on a suspension less bike, the bottom bracket is not part of the main frame (like on the Birdy) but part of the un-suspended rear triangle: the bottom bracket and rear wheel (and both front and rear derailleur) are on one rigid sub-frame so the chain pulling doesn't influence the suspension at all.
The only effect of pedaling on the suspension comes from the cyclist himself mainly when he is pedaling out of the saddle.
Note that not all current Moulton have the unified rear triangle: the AM series (AM GT, AM Speed...) do not have the unified rear triangle, but the Jubilee, Speed, TSR, SST and NS have it (with several variations of it).
The Birdy and Brompton have their bottom bracket part of the main frame with a moving rear arm/triangle.
Now comparing these two bikes with a Moulton is for me unfair because they are both folding bikes and the design of their rear suspension had also to take into account the folding, i.e the rear suspension pivot position wasn't only chosen to optimize the suspension behavior but also the folded size.
This is especially true on the Brompton: moving the rear pivot to the back of the bottom bracket reduced the folded length.
12-30-17, 05:34 PM
#28
Schwinnasaur
Basically when you pedal out of the saddle the entire body gets a vertical up down motion which takes extra energy. But with front suspension, with the latter part of the down stroke of the pedal, the downward motion of the body which is normally arrested by muscles, is at least partially absorbed by the front suspension spring, compressing it. So that stores energy.
In a different part of the pedal stroke, that energy is released again. I have observed that to be about just after the body is lifted up for forcing the opposite pedal down, maybe 2 o'clock. At that moment the spring relaxes again, lifting the frame+body up a bit more, giving a substantial part of the stored energy back.
The overall result is the up down motion is not as sapping as compared to a stiff frame. With some practice you become accustomed to this assistance and you notice it smooths out the pedal action substantially. It's a bit like jogging with sprung shoes.
In a different part of the pedal stroke, that energy is released again. I have observed that to be about just after the body is lifted up for forcing the opposite pedal down, maybe 2 o'clock. At that moment the spring relaxes again, lifting the frame+body up a bit more, giving a substantial part of the stored energy back.
The overall result is the up down motion is not as sapping as compared to a stiff frame. With some practice you become accustomed to this assistance and you notice it smooths out the pedal action substantially. It's a bit like jogging with sprung shoes.
IMO, the value to the shocks derive from the energy of the bumps being absorbed by the shocks instead of your body. Yes, this could potentially result in faster overall speed rates. That seems to be the case for supple tires.
I felt that the Moulton bikes were more plush and comfortable than my other bikes but not enough to compensate for the bobbing and the additional weight of the shocks. I sold my Moutons though I owned each at different time.
On my larger city bike, supple tires do a competent job of damping the bumps without the bobbing of the Moulton bikes, and provides an overall more satisfying ride.
I mostly ride the Brompton now. In the city, it has many pluses. I use supple tires and I made piece with its shock. I think it does slow the ride some, but it’s worth it for the comfort. The shock, being mostly horizontal, the deflects mostly horizontally so you don’t experience its movement as bobbing. It feels more like the wheelbase is expanding rather than bike moving up and down.
12-31-17, 05:05 AM
#29
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I have also a Brompton and a Moulton Speed and also a Passoni Topforce.
But I am living in Europe where there are lots of cobbles roads and cobbles streets in the cities.
Cobbles are a real problem for the Brompton, the rear suspension provide some improvement but the rigid fork (even the Ti one) makes the ride very uncomfortable and force you to slow down if the cobbles are really bad or wet. Unfortunately, there are no really soft tires available for the Brompton that also provide a minimum puncture protection.
On the same road, with the titanium Passoni even with very good wheels (Campagnolo Bora Ultra 50+Veloflex tires) you also need to slow down.
With the Moulton Speed with the excellent Pro One tires, I almost don't feel; the cobbles, it flies above them with its rear wheel keeping the contact with the ground and providing a very good traction. The result is that the Moulton Speed in such condition is much faster than any race road bike. There is a weight difference, but not that much, the Passoni weight about 7.1kg, while the Moulton Speed with lightweight saddle and pedals is at about 8.6kg )both are equipped with s Super Record groupset).
As already said, there is no such thing as "the Moulton", there are several models that behave differently, which one did you test/own ?
But I am living in Europe where there are lots of cobbles roads and cobbles streets in the cities.
Cobbles are a real problem for the Brompton, the rear suspension provide some improvement but the rigid fork (even the Ti one) makes the ride very uncomfortable and force you to slow down if the cobbles are really bad or wet. Unfortunately, there are no really soft tires available for the Brompton that also provide a minimum puncture protection.
On the same road, with the titanium Passoni even with very good wheels (Campagnolo Bora Ultra 50+Veloflex tires) you also need to slow down.
With the Moulton Speed with the excellent Pro One tires, I almost don't feel; the cobbles, it flies above them with its rear wheel keeping the contact with the ground and providing a very good traction. The result is that the Moulton Speed in such condition is much faster than any race road bike. There is a weight difference, but not that much, the Passoni weight about 7.1kg, while the Moulton Speed with lightweight saddle and pedals is at about 8.6kg )both are equipped with s Super Record groupset).
As already said, there is no such thing as "the Moulton", there are several models that behave differently, which one did you test/own ?
12-31-17, 07:41 AM
#30
Schwinnasaur
01-03-18, 03:45 PM
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With your explanation for what causes the pedal induced bob, I have the impression that you do not know or understand what the unified rear triangle is.
The unified rear triangle is a concept where all the rear triangle including the bottom bracket is made in a single piece just like on a suspension less bike, the bottom bracket is not part of the main frame (like on the Birdy) but part of the un-suspended rear triangle: the bottom bracket and rear wheel (and both front and rear derailleur) are on one rigid sub-frame so the chain pulling doesn't influence the suspension at all.
The only effect of pedaling on the suspension comes from the cyclist himself mainly when he is pedaling out of the saddle.
Note that not all current Moulton have the unified rear triangle: the AM series (AM GT, AM Speed...) do not have the unified rear triangle, but the Jubilee, Speed, TSR, SST and NS have it (with several variations of it).
The Birdy and Brompton have their bottom bracket part of the main frame with a moving rear arm/triangle.
Now comparing these two bikes with a Moulton is for me unfair because they are both folding bikes and the design of their rear suspension had also to take into account the folding, i.e the rear suspension pivot position wasn't only chosen to optimize the suspension behavior but also the folded size.
This is especially true on the Brompton: moving the rear pivot to the back of the bottom bracket reduced the folded length.
The unified rear triangle is a concept where all the rear triangle including the bottom bracket is made in a single piece just like on a suspension less bike, the bottom bracket is not part of the main frame (like on the Birdy) but part of the un-suspended rear triangle: the bottom bracket and rear wheel (and both front and rear derailleur) are on one rigid sub-frame so the chain pulling doesn't influence the suspension at all.
The only effect of pedaling on the suspension comes from the cyclist himself mainly when he is pedaling out of the saddle.
Note that not all current Moulton have the unified rear triangle: the AM series (AM GT, AM Speed...) do not have the unified rear triangle, but the Jubilee, Speed, TSR, SST and NS have it (with several variations of it).
The Birdy and Brompton have their bottom bracket part of the main frame with a moving rear arm/triangle.
Now comparing these two bikes with a Moulton is for me unfair because they are both folding bikes and the design of their rear suspension had also to take into account the folding, i.e the rear suspension pivot position wasn't only chosen to optimize the suspension behavior but also the folded size.
This is especially true on the Brompton: moving the rear pivot to the back of the bottom bracket reduced the folded length.
To quote an old country song--I was riding unified rear triangle bikes when full suspension wasn't cool.--- back when Trek/Gary Fisher made them in 1996. The design will work fine on a tightly sprung road bike with short travel. It is horrible in a longer soft travel mountain bike
You are just plain wrong---Mountain bikes have proven your UST theory false. I know you think having all the parts on the rear swing arm changes things but it doesn't. The pivot in relationship to the pulling side of the chain determines pedal induced bob. With the pivot at the BB you will have significant pedal induced BOB with soft travel. You can see as the Trek Y bike evolved they moved the pivot up to the chainline. Look at Y bike pictures.
The mountain bikers have had 20+ years to figure this out and have it down. You will only find your URT (which even the term came from mountain biking) on cheap walmart bikes today.
Last edited by Rick Imby; 01-03-18 at 03:59 PM.
01-03-18, 03:52 PM
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With the pivot at the BB you will have significant pedal induced BOB with soft travel. You can see as the Trek Y bike evolved they moved the pivot up to the chainline. Look at Y bike pictures.
The mountain bikers have had 20+ years to figure this out and have it down. You will only find your URT (which even the term came from mountain biking) on cheap walmart bikes today.
The mountain bikers have had 20+ years to figure this out and have it down. You will only find your URT (which even the term came from mountain biking) on cheap walmart bikes today.
The statement you make that the pivot of the Moulton is at the BB let me think that you never saw a Moulton in real.
Last edited by Jipe; 01-03-18 at 03:56 PM.
01-03-18, 04:07 PM
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With your explanation for what causes the pedal induced bob, I have the impression that you do not know or understand what the unified rear triangle is.
The unified rear triangle is a concept where all the rear triangle including the bottom bracket is made in a single piece just like on a suspension less bike, the bottom bracket is not part of the main frame (like on the Birdy) but part of the un-suspended rear triangle: the bottom bracket and rear wheel (and both front and rear derailleur) are on one rigid sub-frame so the chain pulling doesn't influence the suspension at all.
The only effect of pedaling on the suspension comes from the cyclist himself mainly when he is pedaling out of the saddle.
Isolate the force put on pedals (without thinking of a human on the bike) just see the force pulling on the chain. If the front wheel is up against a wall when you add force to the chain the suspension will collapse some---that is pedal induced bob and you will have it on your UST as long as it is attached to the other part off the frame below the chainline.
Note that not all current Moulton have the unified rear triangle: the AM series (AM GT, AM Speed...) do not have the unified rear triangle, but the Jubilee, Speed, TSR, SST and NS have it (with several variations of it).
The Birdy and Brompton have their bottom bracket part of the main frame with a moving rear arm/triangle.
Now comparing these two bikes with a Moulton is for me unfair because they are both folding bikes and the design of their rear suspension had also to take into account the folding, i.e the rear suspension pivot position wasn't only chosen to optimize the suspension behavior but also the folded size.
This is especially true on the Brompton: moving the rear pivot to the back of the bottom bracket reduced the folded length.
The unified rear triangle is a concept where all the rear triangle including the bottom bracket is made in a single piece just like on a suspension less bike, the bottom bracket is not part of the main frame (like on the Birdy) but part of the un-suspended rear triangle: the bottom bracket and rear wheel (and both front and rear derailleur) are on one rigid sub-frame so the chain pulling doesn't influence the suspension at all.
The only effect of pedaling on the suspension comes from the cyclist himself mainly when he is pedaling out of the saddle.
Isolate the force put on pedals (without thinking of a human on the bike) just see the force pulling on the chain. If the front wheel is up against a wall when you add force to the chain the suspension will collapse some---that is pedal induced bob and you will have it on your UST as long as it is attached to the other part off the frame below the chainline.
Note that not all current Moulton have the unified rear triangle: the AM series (AM GT, AM Speed...) do not have the unified rear triangle, but the Jubilee, Speed, TSR, SST and NS have it (with several variations of it).
The Birdy and Brompton have their bottom bracket part of the main frame with a moving rear arm/triangle.
Now comparing these two bikes with a Moulton is for me unfair because they are both folding bikes and the design of their rear suspension had also to take into account the folding, i.e the rear suspension pivot position wasn't only chosen to optimize the suspension behavior but also the folded size.
This is especially true on the Brompton: moving the rear pivot to the back of the bottom bracket reduced the folded length.
01-03-18, 04:13 PM
#35
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UST was invented for MTN bikes in the 90's and was a failure because of pedal induced Bob. When they moved the pivot up to the chainline it worked better but then many other designs were developed that work better for long travel.
From my year of riding a Fisher UST, it is excellent for climbing traction but even pedalling softly from the seat you would get significant pedal induced BOB.
Here is a quote from Wikipedia on UST
Unified rear triangle[edit]
The unified rear triangle or "URT" for short, keeps the bottom bracket and rear axle directly connected at all times. Suspension action is provided between the rear triangle, which unites rear axle and bottom bracket, and the front triangle, which unites seat and front axle. This design uses only one pivot, which keeps the number of moving parts down. The fixed length between bottom bracket and rear axle gives the URT the advantage of zero chain growth and consistent front derailleur shifting. Additionally the bike is easily modified into a single-speed. However, as the URT's suspension moves, the distance between seat and pedals changes, detracting from pedaling efficiency. Furthermore, when the rider shifts any weight from the seat to the pedals, he or she is shifting weight from the sprung part of the bike to the unsprung parts. As such, part of the rider's weight is no longer suspended by the suspension system. Since pedaling itself is a shift of this weight, the design is very prone to suspension bob.
Notable examples of bikes with this type of suspension include the Ibis Szazbo, Klein Mantra, Schwinn S-10, and Trek Y.
From my year of riding a Fisher UST, it is excellent for climbing traction but even pedalling softly from the seat you would get significant pedal induced BOB.
Here is a quote from Wikipedia on UST
Unified rear triangle[edit]
The unified rear triangle or "URT" for short, keeps the bottom bracket and rear axle directly connected at all times. Suspension action is provided between the rear triangle, which unites rear axle and bottom bracket, and the front triangle, which unites seat and front axle. This design uses only one pivot, which keeps the number of moving parts down. The fixed length between bottom bracket and rear axle gives the URT the advantage of zero chain growth and consistent front derailleur shifting. Additionally the bike is easily modified into a single-speed. However, as the URT's suspension moves, the distance between seat and pedals changes, detracting from pedaling efficiency. Furthermore, when the rider shifts any weight from the seat to the pedals, he or she is shifting weight from the sprung part of the bike to the unsprung parts. As such, part of the rider's weight is no longer suspended by the suspension system. Since pedaling itself is a shift of this weight, the design is very prone to suspension bob.
Notable examples of bikes with this type of suspension include the Ibis Szazbo, Klein Mantra, Schwinn S-10, and Trek Y.
01-04-18, 05:29 AM
#36
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We are not discussing about mountain bike suspension but about a road bike suspension.
Mountain bike and road bike have different requirements. This is valid for all parts of the bike, for the suspension, for braking... When people tried to use mountain bike disc brakes for road bike they also discovered that these brakes weren't working well on road bike because they weren't designed to slow down a bike riding downhill at 90km/h !
All these explanations and your experience is about mountain bike and isn't applicable to a different road bike suspension design, the only common point between these several mountain bike suspensions and the Moulton suspension is the name UST.
For the Birdy, indeed, the pivot is placed a little bit higher, but as said, the suspension design is constrained by the folding requirements.
Mountain bike and road bike have different requirements. This is valid for all parts of the bike, for the suspension, for braking... When people tried to use mountain bike disc brakes for road bike they also discovered that these brakes weren't working well on road bike because they weren't designed to slow down a bike riding downhill at 90km/h !
All these explanations and your experience is about mountain bike and isn't applicable to a different road bike suspension design, the only common point between these several mountain bike suspensions and the Moulton suspension is the name UST.
For the Birdy, indeed, the pivot is placed a little bit higher, but as said, the suspension design is constrained by the folding requirements.
Last edited by Jipe; 01-04-18 at 05:34 AM.
01-04-18, 06:23 AM
#37
Senior Member
https://www.flickr.com/photos/anglep...oulton_am-atb/
and second this proves (again) that "the" Moulton does not exist and so does not "the" Moulton's suspension. Something some people in this thread are very reluctant to understand.
01-04-18, 06:44 AM
#38
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Even better: Moulton made in the 80ies the grandfather of all suspended MTBs, called the AM-ATB. For one it did NOT have a unified rear triangle
https://www.flickr.com/photos/anglep...oulton_am-atb/
and second this proves (again) that "the" Moulton does not exist and so does not "the" Moulton's suspension. Something some people in this thread are very reluctant to understand.
https://www.flickr.com/photos/anglep...oulton_am-atb/
and second this proves (again) that "the" Moulton does not exist and so does not "the" Moulton's suspension. Something some people in this thread are very reluctant to understand.
I didn't mention the ATB because it is a kind of exception in the range of Moulton bikes. The pivot of the ATB is placed like on the AM road bikes but the upper part of the suspension is lower, but not as low on the APB
And indeed, there are many different Moulton bikes. Bikes like the APB and current TSR, SST, NS Marathon are all purpose comfortable touring bikes.
If we want to talk about performances, we must consider one of the speed models.
Look also at the following pictures, they show side by side several models that globally seem the same but when put side by side are obviously different.
Last edited by Jipe; 01-04-18 at 06:47 AM.
01-05-18, 10:26 AM
#39
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We are not discussing about mountain bike suspension but about a road bike suspension.
Mountain bike and road bike have different requirements. This is valid for all parts of the bike, for the suspension, for braking... When people tried to use mountain bike disc brakes for road bike they also discovered that these brakes weren't working well on road bike because they weren't designed to slow down a bike riding downhill at 90km/h !
All these explanations and your experience is about mountain bike and isn't applicable to a different road bike suspension design, the only common point between these several mountain bike suspensions and the Moulton suspension is the name UST.
For the Birdy, indeed, the pivot is placed a little bit higher, but as said, the suspension design is constrained by the folding requirements.
Mountain bike and road bike have different requirements. This is valid for all parts of the bike, for the suspension, for braking... When people tried to use mountain bike disc brakes for road bike they also discovered that these brakes weren't working well on road bike because they weren't designed to slow down a bike riding downhill at 90km/h !
All these explanations and your experience is about mountain bike and isn't applicable to a different road bike suspension design, the only common point between these several mountain bike suspensions and the Moulton suspension is the name UST.
For the Birdy, indeed, the pivot is placed a little bit higher, but as said, the suspension design is constrained by the folding requirements.
Pedal induced Bob is caused when POWER to the pedals (not the motion of the human rider) causes the suspension to collapse. This occurs more with the Moulton URT than with the Birdy which has it's pivot nearly inline with the chain.----This was the initial thread question and my answer is correct.
Rider induced Bob is caused by the up and down motion of a rider when powering the bicycle.
With significantly more travel available in the Birdy and probably softer spring action and damping the Birdy will probably suffer more rider induced bob than the Moulton.
It was difficult for Birdy to move the pivot location---folding designs are much simpler when you pivot the rear end (URT usually) at the BB.
One of the first GT bike full suspensions was the RTS which actually reversed bob---it raised the rear wheel slightly when power was applied.
I have played with Car suspension (normally car suspension is designed to compress the rear a little as you accelerate---this can be easily changed with some suspensions and usually is for street racing regular cars.
My buddy had a Yamaha 1100 shaft drive in the late 70s that the seat went up when he accelerated hard.
@Jipe I may not have done a very good job of describing things but the URT as Moulton applies it is not a solution to Bob. But it probably works fine for a road suspension.---grin---
Enjoy the ride no matter what your bike is....
01-05-18, 03:20 PM
#40
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But both bike have riders induced bob, the Moulton Speed has the smallest, followed by the Moulton Jubilee and the Birdy has the biggest.
What Moulton model did you tested to state that the Moulton has more bob than the Birdy (and what Birdy did you test) ?
01-05-18, 04:23 PM
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Jipe---It is hard from riding the bike to tell what bob is from (Pedal or Rider). It is very easy when looking at the bikes from the side to tell. I have no doubt the Birdy has more rider induced bob.
With the Moulton front wheel stopped by a wall with you on your bike add power to the pedals. The BB will go down... Power induced bob---you cannot avoid it with the pivot located where it is.
Schwinn and other companies moved the pivot up from the bb (Sweet Spot) and that still did not solve it. Just the action of adding power to a URT causes Pedal induced bob.----It is probably very minimal with your Moulton---which is an awesome bike by the way.
Just the transfer of weight from the upper frame to the lower frame when applying power with the URT will create bob. Search "URT Bike Wikipedia" for a better explanation.
I was also wrong about a previous statement whereas you were correct. I was talking about pedal induced Bob and the thread is about overall Bob. I agree with you that the Birdy would have more total bob.
Great talking suspension with you---Have a great weekend---Rick
With the Moulton front wheel stopped by a wall with you on your bike add power to the pedals. The BB will go down... Power induced bob---you cannot avoid it with the pivot located where it is.
Schwinn and other companies moved the pivot up from the bb (Sweet Spot) and that still did not solve it. Just the action of adding power to a URT causes Pedal induced bob.----It is probably very minimal with your Moulton---which is an awesome bike by the way.
Just the transfer of weight from the upper frame to the lower frame when applying power with the URT will create bob. Search "URT Bike Wikipedia" for a better explanation.
I was also wrong about a previous statement whereas you were correct. I was talking about pedal induced Bob and the thread is about overall Bob. I agree with you that the Birdy would have more total bob.
Great talking suspension with you---Have a great weekend---Rick
01-07-18, 02:08 PM
#42
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Jipe---It is hard from riding the bike to tell what bob is from (Pedal or Rider). It is very easy when looking at the bikes from the side to tell. I have no doubt the Birdy has more rider induced bob.
With the Moulton front wheel stopped by a wall with you on your bike add power to the pedals. The BB will go down... Power induced bob---you cannot avoid it with the pivot located where it is.
Schwinn and other companies moved the pivot up from the bb (Sweet Spot) and that still did not solve it. Just the action of adding power to a URT causes Pedal induced bob.----It is probably very minimal with your Moulton---which is an awesome bike by the way.
Just the transfer of weight from the upper frame to the lower frame when applying power with the URT will create bob. Search "URT Bike Wikipedia" for a better explanation.
I was also wrong about a previous statement whereas you were correct. I was talking about pedal induced Bob and the thread is about overall Bob. I agree with you that the Birdy would have more total bob.
Great talking suspension with you---Have a great weekend---Rick
With the Moulton front wheel stopped by a wall with you on your bike add power to the pedals. The BB will go down... Power induced bob---you cannot avoid it with the pivot located where it is.
Schwinn and other companies moved the pivot up from the bb (Sweet Spot) and that still did not solve it. Just the action of adding power to a URT causes Pedal induced bob.----It is probably very minimal with your Moulton---which is an awesome bike by the way.
Just the transfer of weight from the upper frame to the lower frame when applying power with the URT will create bob. Search "URT Bike Wikipedia" for a better explanation.
I was also wrong about a previous statement whereas you were correct. I was talking about pedal induced Bob and the thread is about overall Bob. I agree with you that the Birdy would have more total bob.
Great talking suspension with you---Have a great weekend---Rick
I did it with cliplsess pedals and besides a mirror to be able to look at the rear suspension.
I first did a test sitting on the bike with clipless shoes clipped into the pedals and by applying a pure torque on the crank by pushing with one shoe/foot, pulling with the other show/foot (like in normal uphill fast cadence soft push pedaling on a road race bike) while braking on the rear wheel.
When doing so, there was zero visible effect on the rear suspension or rear triangle position wrt. the frame.
When I either brake the front wheel or block it against something, then there is some BOB... on the front fork.
More with the Jubilee than with the Speed which was expected because both suspensions of the Jubilee are stiffer (and also the Jubilee has a Monosphere rear suspension while the Speed has the more sophisticated Hydrolastic rear suspension).
When I only push no too strong on one pedal without pulling with rear braking, there is a small effect on the rear suspension that decompress which is expected because there is some transfer of my mass to the front of the bike.
If I also pull on the handlebar with a strong push on one pedal l(like in case of normal strong push pedaling without clipless pedals) with rear braking, then there is a small compression of the rear suspension.
I think that your different experience with mountain bikes comes from the fact that the mountain bike suspension are much more softer with a much bigger suspension travel.
Actually, the goal of the suspension of the Moulton is different from the one of mountain bikes: the Moulton uses high pressure, narrow road tires and its suspension role is to suppress the vibrations of rough roads up to cobbles to provide an efficient power transfer+riding and comfort . For mountain bikes, the vibration suppression is done to a big extend by the wide, low pressures tires while the suspension is there to cope with big surface discontinuities like big holes, steps, stones...
In real world use, the Moulton like high cadence soft push, sitting on the saddle pedaling for going uphill, the Froome type of uphill pedaling and like less the off saddle strong push with big cyclist movement pedaling, the Contador type of uphill pedaling.
Last edited by Jipe; 01-07-18 at 03:56 PM.
01-11-18, 07:31 AM
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Reminds me of the old Mantis mountain bikes from the 80s (Richard Cunningham designs)... How do you pick which beauty to ride? The stem on the painted bike is foreign to me---can you take another view or two of it?
01-11-18, 08:16 AM
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Actually, the red one has now mudguards+lights on top of the Brompton front bag (I can also mount a slightly adapted S-bag) block and is more "military" than the speed that cannot accept mudguards, front bag...
The stem is the Moulton Wishbone Stem it exist in Ahead and quill type Moulton Wishbone Stem Update.pdf https://fudgescyclesonline.com/index.php?p=195522 https://fudgescyclesonline.com/index.php?p=192767
It is unfortunately a little heavy (but anyway, the "naked" Jubillee (no rack, bag, bottle, pump, U-lock) with wishbone is exactly 10kg).
The stem is the Moulton Wishbone Stem it exist in Ahead and quill type Moulton Wishbone Stem Update.pdf https://fudgescyclesonline.com/index.php?p=195522 https://fudgescyclesonline.com/index.php?p=192767
It is unfortunately a little heavy (but anyway, the "naked" Jubillee (no rack, bag, bottle, pump, U-lock) with wishbone is exactly 10kg).
Last edited by Jipe; 01-11-18 at 11:00 AM.
01-17-18, 02:17 PM
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Hi Jipe those Moultons look pretty special. Looking at those seatposts you must be pretty tall ...arn't the bars a bit too far over the front wheel.
I'm 1.82m and find my '65 Moulton a bit of a stretch down to the handlebars. I've not a had the opportunity to try a new version to see how I fit, they're extremely thin on the ground here in Switzerland. I've read that they are a bit short in the frame.
Any info would be welcome and keep posting photos of both of them!
Thanks
Andy
I'm 1.82m and find my '65 Moulton a bit of a stretch down to the handlebars. I've not a had the opportunity to try a new version to see how I fit, they're extremely thin on the ground here in Switzerland. I've read that they are a bit short in the frame.
Any info would be welcome and keep posting photos of both of them!
Thanks
Andy
01-18-18, 03:23 AM
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Hi Jipe those Moultons look pretty special. Looking at those seatposts you must be pretty tall ...arn't the bars a bit too far over the front wheel.
I'm 1.82m and find my '65 Moulton a bit of a stretch down to the handlebars. I've not a had the opportunity to try a new version to see how I fit, they're extremely thin on the ground here in Switzerland. I've read that they are a bit short in the frame.
Any info would be welcome and keep posting photos of both of them!
Thanks
Andy
I'm 1.82m and find my '65 Moulton a bit of a stretch down to the handlebars. I've not a had the opportunity to try a new version to see how I fit, they're extremely thin on the ground here in Switzerland. I've read that they are a bit short in the frame.
Any info would be welcome and keep posting photos of both of them!
Thanks
Andy
The long stem is OK for my size, the Moulton frame is equivalent to a size 54 frame, I typically need a size 55 or 56 and these long stem add the centimeter(s) missing in the frame.
There is a Mouton distributor/dealer in Switzerland in Geneva it is Bikes2fold: MOULTON SUISSE, actually the red Jubilee comes from Bikes2fold.
There is a big distributor in Germany Alex Moulton Fahrräder Import Heusenstamm bei Frankfurt with several dealers Händler who have test/demonstration Moulton bikes.
But the Moulton bikes are quite expensive in Germany, they are cheaper in UK and Switzerland.
01-22-18, 02:57 PM
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Hi Jipe
thanks for the info
"Moulton frame is equivalent to a size 54 frame"
This is what I understood. The MK3 was shrunk compared to the MK1/Mk2 F-frame and then they used the same basic geometry for the following spacefame models.
I normally ride a 58 race frame, so a 54 is quite a step down even with extended stems etc.
The dealer info is great, unfortunately I live the wrong side of Switzerland for Genf and Frankfurt is even further away. I've since found a place here in Zurich that might have a demo bike so I'll be investigating further despite the size issues.
Thanks
Andrew
thanks for the info
"Moulton frame is equivalent to a size 54 frame"
This is what I understood. The MK3 was shrunk compared to the MK1/Mk2 F-frame and then they used the same basic geometry for the following spacefame models.
I normally ride a 58 race frame, so a 54 is quite a step down even with extended stems etc.
The dealer info is great, unfortunately I live the wrong side of Switzerland for Genf and Frankfurt is even further away. I've since found a place here in Zurich that might have a demo bike so I'll be investigating further despite the size issues.
Thanks
Andrew
01-22-18, 03:09 PM
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And to get back on track re BOB...
my 1965 Moulton bobs very gently when, whilst seated, attempting to force the pace, something I'm not accustomed too after riding rigid races for ever.
It probably means I need to pedal a bit smoother and I need to try out my sons old fully suspended Cannondale Scapel that has no pivots but uses flexing carbon chainstays and a damper.
Cheers
Andrew
my 1965 Moulton bobs very gently when, whilst seated, attempting to force the pace, something I'm not accustomed too after riding rigid races for ever.
It probably means I need to pedal a bit smoother and I need to try out my sons old fully suspended Cannondale Scapel that has no pivots but uses flexing carbon chainstays and a damper.
Cheers
Andrew