|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Is seat suspension enough?
Is seat suspension enough?
It is relatively complicated to have suspension in a bike so that front and back are suspended with independent systems. Is it really useful and necessary to do so in recumbents? Is it enough for all practical purposes to suspend the seat only? If in an upright bike you suspend the seat to move softly up and down, you assumably get movement in accordance of pedaling, 'pogo'. The direction of forces in legs is down. If the total force to the pedals in vertical direction diminishes, the seat goes down. When it increases, it goes up. The weight distribution of the driver varies between the pedals and the seat, causing irritating movement up and down. But in a recumbent there should be no 'pogo' in the vertical direction! ? If the seat is prevented to move in a horizontal direction (forward and backward, and side to side) but is free to move up and down within limits, suspended, there seems to be a possibility to have one suspension system instead of two and get almost as good results as with two. Almost? The suspended mass in this system is the driver plus seat, e.g. 70 kg, and the unsuspended mass e.g. 15 kg. In two suspension system the corresponding numbers might be 80 kg and 5 kg (at best). The difference in unsuspended mass might be 3-fold, but the difference in suspended mass only 15 %. Where and how does this make an observable difference? (feelings and beliefs excluded for a moment ) If I in an unsuspended upright bike need to provide the bike with a temporary 'suspension' when meeting an obstacle, I stand on the pedals instead of sitting on the saddle. Then everything goes as smoothly as I can imagine. If I have seat suspension in an recumbent, is that a practcally equivalent system? I intend to build my 3. recumbent for casual riding. For that project I need to decide: 2 suspension systems or only one? When asking this now I notice that it might be possible to observe some of the essential differences by taking a 2-suspension bike and add different weights around the front wheel and back wheel for the test rides... Sorry, I might have bothered this newsgroup in vain . But seriously, has anyone of the readers tested these differences? Observations? |
Ads |
#2
|
|||
|
|||
Is seat suspension enough?
I have found that my unsuspended Gold Rush gives a smoother ride than my
3-wheel independent suspended Leitra. I believe that the difference is mainly due to the Gold Rush's longer wheelbase, but the Gold Rush has a much plusher seat, so that may be part of it, too. So your question should take into account the bike design you are considering. Oh, one other data point, my E2 has a lot of travel in the suspension of its rear wheel, and the rear rider gets a silky smooth ride. The front wheel is unsuspended, and the front rider gets jolted over bumps. I would use a Pantour suspension hub on the front wheel, but I don't think there is enough clearance between the fork and tire. Alan Weiss NJ Gold Rush, E2 tandem, and Leitra rider |
#3
|
|||
|
|||
Is seat suspension enough?
"Mother's Cut-Rate Recumbent" has front of seat on pivots and rear
attached to spring-loaded plunger from top of seat to frame. You-build-It article at: http://www.motherearthnews.com/menar...&ID=2613&Num=4 |
#4
|
|||
|
|||
Is seat suspension enough?
I can offer this bit of personal observation. On some of the rough stuff I
ride over, the rear suspension on my Vivo is working hard. Even on rougher pavement or sidewalks it is pretty active. I have a fender now, so I can reach back and rest my hand on top of that while riding, and it goes up and down constantly. Or, I can reach down and feel the suspension pivot point, and feel the rear triangle (I don't know what this is actually called - the rear fork) change angle with respect to the bike frame. It moves rapidly and constantly. This action helps soak up bumps for my comfort, but it also helps keep the wheel in contact with the road, for traction. If I had suspension on my seat instead, I may actually soak up jarring better and give me more comfort; I don't know. But there is no way the entire bike frame could pivot with respect to my body to keep the wheel in contact with the road nearly as rapidly or effectively as the rear suspension does. I think for just street use, a seat suspension may very well make more sense, since it allows for more elegant frame geometries, lighter weight, and greater simplicity. For use on more varied terrain, suspesion near the wheels is the way to go. -- David Luecke Ridin' a RANS Vivo (wahoo!) Merritt Island, Florida USA |
#5
|
|||
|
|||
Is seat suspension enough?
On the Rotator seat we use elastic cord to tie the fabric to the seat frame, on
the bottom section only. This works like a simple suspension and gives about 3" movement. Not enough for curb jumping. Super on the cobblestones. As a side benefit the fabric contours to the human shape, spreading the load over a wider area which helps fight the dreaded "recumbent butt" My 2 cents Speedy www.rotatorrecumbent.com optimistx wrote: Is seat suspension enough? It is relatively complicated to have suspension in a bike so that front and back are suspended with independent systems. Is it really useful and necessary to do so in recumbents? Is it enough for all practical purposes to suspend the seat only? If in an upright bike you suspend the seat to move softly up and down, you assumably get movement in accordance of pedaling, 'pogo'. The direction of forces in legs is down. If the total force to the pedals in vertical direction diminishes, the seat goes down. When it increases, it goes up. The weight distribution of the driver varies between the pedals and the seat, causing irritating movement up and down. But in a recumbent there should be no 'pogo' in the vertical direction! ? If the seat is prevented to move in a horizontal direction (forward and backward, and side to side) but is free to move up and down within limits, suspended, there seems to be a possibility to have one suspension system instead of two and get almost as good results as with two. Almost? The suspended mass in this system is the driver plus seat, e.g. 70 kg, and the unsuspended mass e.g. 15 kg. In two suspension system the corresponding numbers might be 80 kg and 5 kg (at best). The difference in unsuspended mass might be 3-fold, but the difference in suspended mass only 15 %. Where and how does this make an observable difference? (feelings and beliefs excluded for a moment ) If I in an unsuspended upright bike need to provide the bike with a temporary 'suspension' when meeting an obstacle, I stand on the pedals instead of sitting on the saddle. Then everything goes as smoothly as I can imagine. If I have seat suspension in an recumbent, is that a practcally equivalent system? I intend to build my 3. recumbent for casual riding. For that project I need to decide: 2 suspension systems or only one? When asking this now I notice that it might be possible to observe some of the essential differences by taking a 2-suspension bike and add different weights around the front wheel and back wheel for the test rides... Sorry, I might have bothered this newsgroup in vain . But seriously, has anyone of the readers tested these differences? Observations? -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#6
|
|||
|
|||
Is seat suspension enough?
"S. Delaire \"Rotatorrecumbent\"" wrote in message ...
On the Rotator seat we use elastic cord to tie the fabric to the seat frame, on the bottom section only. This works like a simple suspension and gives about 3" movement. Not enough for curb jumping. Super on the cobblestones. As a side benefit the fabric contours to the human shape, spreading the load over a wider area which helps fight the dreaded "recumbent butt" My 2 cents Speedy www.rotatorrecumbent.com Speaking from 3 happy years with a Rotator Tiger, I can make a few points based on "seat of the pants" type knowledge of the Rotator suspended mesh-seat-fabric form of recumbent seat. I am quite happy with both the seat and the bike. -The elastic-suspended-bottom Rotator seat is a genuinely cushy ride. This is due to seat seaign, long monotube frame design, and and the Rotator's rider position centre of gravity. and Steve Delaire seems to have found a pretty good recipe for providing great comfort but without a speed penalty or complexity issues. -It is a very effective simple, uncomplex, low technology solution to the support of the human body, and the protection of that body from small and large irregularities one travels along, through, and over. This is a good thing. Burt Rutan is similar in some small way to this in not over-engineering the solutions to the assorted design challenges inherent in a lightweight structure like a bicycle or airplane. -The seat can be very low -The seat can be very light -The elastic cord will fray or cut in a fall (more like a baseball-style slide actually), and replacement elastic cord, if you bought cheap elastic, will fray and break from the stretching in the normal course of suspending the body. -The seat can be adjusted in a very wide range of positions. The ride can be quite low and stretched out. I am always amazed at how flat and low the rider looks on this bike when ever I see someone else riding it. I possibly have my seat more reclined than typical, but it works for me, perhaps cuz I am quite tall, on the other hand maybe shorter test riders have to stretch out more to reach the pedals and this is what I see. -Assorted pockets for things can be sewn to the seat mesh. You can sew sleeves and pockets for things such as camelbak sleeves, thermarest pads, tool pouch, personal massagers, etc. Next winter I am doing a pocket for the camel bak. -I have not often had a sore butt riding this bike. It was very comfortable the very first time I rode it. -It is quite conformal to the shape of the rider. It fits you, it is not one of those "you must fit it" rigid seats. -The mesh is quite comfortable and keeps you fresh in warm conditions. However when you go through a puddle, you get a back shower through the seat. SO far this is the only negative thing I have found about this seat or the entire bike for that matter -- and it is the only time I swear "kaw-liss" at this bike, and I like to swear a lot. -I think the seat may contribute to the slightly (and highly debatable) homebuilt look the bike has. I only mention this cuz so many people ask me if I built it myself. In fact that is a pretty common ice-breaker people use to initiate a chat with me. (I think one woman asked me "patantez vous ca toi meme?" -- as you can see my french is awful-spelling, grammar, and pronounciation!) Often, this is a cue to accellerate, especially when the ask how many gears the bike has, so I just show them! -The metal tubing that the seat is laced to, can be used to hook a large seat bag on to. I took a normal "on top of the rear bike rack" bag and had a little loop sewn on each end and hooked it on the seat. it looks like it was made for the bike. The seat can be fixed or repaired at any place that does sewing repairs, like a shoemaker, a place that does luggage or backpack repairs, or even a seamstress. I keep a metre ort so of spare cord in the tool kit, and I know I will always get home if bad stuff happens to the existing cord or elastic. (especially useful when far from home -- the cord can even be used for towing the less fortunate -extremely not recommended!) With the seat's simple, open construction, it is easy to attach a home built tailbox. First, build a coroplast tailbox using some free coroplast and a few ziplocks. With "democratic" elections, there's an irregular but free supply of fresh coroplast once the vote is over and the campaign signs become instant and pure landfill. Re-use! Experiment! Go nutz and create a corpolast art-bike if speed isn't your thing. Of course, this might add a bit too much attention for you quieter types since the bike already attracts a considerable amount of bystander attention. I might correct myself and state that it will take a big bunch of ziplocks, not just a few. I prototype/temporarily rig with the plastic covered wire that is available in a roll at the hardware store (what am I talking about it is the stuff like what is used to close plastic bread bags, electronic component bags, etc. And now, a digression involving one man's long-time fantasy accessory for his rotator seat. I would like to get little speakers (small, cheap, black golf ball sized) that attach on the bottom end of the seat rail (on the outside of my thighs) so I can plug in my walkman and hear the radio or motivational music. It doesn't have to be loud (and no I don't ride with earplugs, or music at all now). I want the sound to be very directional so when they are pointed upwards towards my head and ears, no one off the side will hear it, all the sound will go upwards only, not outwards around me (so it won't disturb other riders). I'd like this designed for christmas please. Digressing further, much, much further, I would also consider, miracle-fabric-enclosed flat panel speakers that slide inside my bike shorts on the top of my thighs would be also fine and dandy. (Hello mit media lab, anyone looking for a thesis project?) All in all, the seat is one of the best of the many good things about the Rotator bikes. (besides the seat, this includes mid-drive, low position, monotube design, oss, and for the tiger, a somewhat manageable size and length of the bike). People ask me, "is it (the bike or the seat) comfortable?" and I reply, it is not only comfortable, it is fast. Not one or the other. Both. And that's all I really want from a bicycle, even all I want out of life! tiger |
#7
|
|||
|
|||
Is seat suspension enough?
"S. Delaire \"Rotatorrecumbent\"" wrote in message ...
On the Rotator seat we use elastic cord to tie the fabric to the seat frame, on the bottom section only. This works like a simple suspension and gives about 3" movement. Not enough for curb jumping. Super on the cobblestones. As a side benefit the fabric contours to the human shape, spreading the load over a wider area which helps fight the dreaded "recumbent butt" My 2 cents Speedy www.rotatorrecumbent.com Speaking from 3 happy years with a Rotator Tiger, I can make a few points based on "seat of the pants" type knowledge of the Rotator suspended mesh-seat-fabric form of recumbent seat. I am quite happy with both the seat and the bike. -The elastic-suspended-bottom Rotator seat is a genuinely cushy ride. This is due to seat seaign, long monotube frame design, and and the Rotator's rider position centre of gravity. and Steve Delaire seems to have found a pretty good recipe for providing great comfort but without a speed penalty or complexity issues. -It is a very effective simple, uncomplex, low technology solution to the support of the human body, and the protection of that body from small and large irregularities one travels along, through, and over. This is a good thing. Burt Rutan is similar in some small way to this in not over-engineering the solutions to the assorted design challenges inherent in a lightweight structure like a bicycle or airplane. -The seat can be very low -The seat can be very light -The elastic cord will fray or cut in a fall (more like a baseball-style slide actually), and replacement elastic cord, if you bought cheap elastic, will fray and break from the stretching in the normal course of suspending the body. -The seat can be adjusted in a very wide range of positions. The ride can be quite low and stretched out. I am always amazed at how flat and low the rider looks on this bike when ever I see someone else riding it. I possibly have my seat more reclined than typical, but it works for me, perhaps cuz I am quite tall, on the other hand maybe shorter test riders have to stretch out more to reach the pedals and this is what I see. -Assorted pockets for things can be sewn to the seat mesh. You can sew sleeves and pockets for things such as camelbak sleeves, thermarest pads, tool pouch, personal massagers, etc. Next winter I am doing a pocket for the camel bak. -I have not often had a sore butt riding this bike. It was very comfortable the very first time I rode it. -It is quite conformal to the shape of the rider. It fits you, it is not one of those "you must fit it" rigid seats. -The mesh is quite comfortable and keeps you fresh in warm conditions. However when you go through a puddle, you get a back shower through the seat. SO far this is the only negative thing I have found about this seat or the entire bike for that matter -- and it is the only time I swear "kaw-liss" at this bike, and I like to swear a lot. -I think the seat may contribute to the slightly (and highly debatable) homebuilt look the bike has. I only mention this cuz so many people ask me if I built it myself. In fact that is a pretty common ice-breaker people use to initiate a chat with me. (I think one woman asked me "patantez vous ca toi meme?" -- as you can see my french is awful-spelling, grammar, and pronounciation!) Often, this is a cue to accellerate, especially when the ask how many gears the bike has, so I just show them! -The metal tubing that the seat is laced to, can be used to hook a large seat bag on to. I took a normal "on top of the rear bike rack" bag and had a little loop sewn on each end and hooked it on the seat. it looks like it was made for the bike. The seat can be fixed or repaired at any place that does sewing repairs, like a shoemaker, a place that does luggage or backpack repairs, or even a seamstress. I keep a metre ort so of spare cord in the tool kit, and I know I will always get home if bad stuff happens to the existing cord or elastic. (especially useful when far from home -- the cord can even be used for towing the less fortunate -extremely not recommended!) With the seat's simple, open construction, it is easy to attach a home built tailbox. First, build a coroplast tailbox using some free coroplast and a few ziplocks. With "democratic" elections, there's an irregular but free supply of fresh coroplast once the vote is over and the campaign signs become instant and pure landfill. Re-use! Experiment! Go nutz and create a corpolast art-bike if speed isn't your thing. Of course, this might add a bit too much attention for you quieter types since the bike already attracts a considerable amount of bystander attention. I might correct myself and state that it will take a big bunch of ziplocks, not just a few. I prototype/temporarily rig with the plastic covered wire that is available in a roll at the hardware store (what am I talking about it is the stuff like what is used to close plastic bread bags, electronic component bags, etc. And now, a digression involving one man's long-time fantasy accessory for his rotator seat. I would like to get little speakers (small, cheap, black golf ball sized) that attach on the bottom end of the seat rail (on the outside of my thighs) so I can plug in my walkman and hear the radio or motivational music. It doesn't have to be loud (and no I don't ride with earplugs, or music at all now). I want the sound to be very directional so when they are pointed upwards towards my head and ears, no one off the side will hear it, all the sound will go upwards only, not outwards around me (so it won't disturb other riders). I'd like this designed for christmas please. Digressing further, much, much further, I would also consider, miracle-fabric-enclosed flat panel speakers that slide inside my bike shorts on the top of my thighs would be also fine and dandy. (Hello mit media lab, anyone looking for a thesis project?) All in all, the seat is one of the best of the many good things about the Rotator bikes. (besides the seat, this includes mid-drive, low position, monotube design, oss, and for the tiger, a somewhat manageable size and length of the bike). People ask me, "is it (the bike or the seat) comfortable?" and I reply, it is not only comfortable, it is fast. Not one or the other. Both. And that's all I really want from a bicycle, even all I want out of life! tiger |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
if you wanted maximum braking, where would you sit? | wle | Techniques | 133 | November 18th 15 02:10 AM |
Seatpost terminology: "12-Degree Clamp" ? | (Pete Cresswell) | Techniques | 6 | April 25th 04 12:06 AM |
suspension seat post opinions | bb | General | 4 | October 21st 03 03:16 PM |