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Recumbent What IS that thing?! Recumbents may be odd looking, but they have many advantages over a "wedgie" bicycle. Discuss the in's and out's recumbent lifestyle in the recumbent forum.

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Old 11-02-09, 01:48 PM   #1
bokes
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a suspended seat, does this exist?

Hi all, I have a question. I've had back surgery, so I need some cushion to protect my spine. Unfortunately, I'm not really a fan of dual suspension either, because it adds weight, robs some energy, and for a touring bike, adds risk of breakdown. In the upright world, the perfect solution for me was a suspension seatpost. Now that I'm getting into recumbents, it would seem my ideal bike would be rigid, but have a suspended seat, something like the homebrew solution this guy made:



My question is, does anyone make something like this? btw I know that most recumbent seats are soft and absorb small bumps. I rented a Giro 26 for a week and agree that for most roads there was no problem. But I had to slow to crawling speed for any bump that was bigger than say, a 1/2". That would get annoying after awhile having to do this all the time.
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Old 11-02-09, 02:54 PM   #2
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Not that I'm aware of. The old Pashley PDQ had an elastomer where the back brace mounted to the frame, but it was basically to soak up small vibrations.
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Old 11-02-09, 03:06 PM   #3
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There is one DF bike with suspension that might be what you're looking for. Its call the Pedersen Bike. Its unique hammock like seat might be what you're looking for:




The saddle is completely insulated from the frame and the road. Next to a recument, its probably the best solution for someone with a back problem.

Check it out.
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Old 11-02-09, 04:40 PM   #4
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There are no production seat suspensions that I'm aware of.

If you're going make your own some advice from someone whose already been there.

1) A poorly designed seat suspension will rob energy as quickly as a poorly designed frame suspension. Problem is that most designs do not take into account the torque placed on each pivot point. In fact, most seat suspensions I've ever seen or tried myself is actually more susceptible to pedal pogo.

2) Suspension has two general functions. Comfort and traction. Off road designs tend to give more comfort as a result of increasing traction for the very large bumps encountered. Road suspension generally cannot give lots of comfort while maintaining traction.... think sports car vs limousine.

3) Good tires provide more bang for buck than suspension.

4) Sometimes a good recumbent seat can more than make up for the lack of suspension.

5) If you still insist on making one, study all of the existing types and understand the compromises inherent in the design. Landmark designs include Alex Moulton (including the damping system of the original Mini Cooper), Horst Leitner (which is a transverse MacPherson Strut) and the Slingshot MTB. Another place to look is in motor racing of all types, where suspensions have often proven to be the difference between win and lose.

:)ensen.
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Old 11-02-09, 05:40 PM   #5
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An inflatable chair pad would be more comfy and lighter,IMO.

Plus it can double as a water bladder...how cool would that be to basically ride on a water bed, hahaha
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Old 11-05-09, 05:54 PM   #6
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Andrew Carson has a diy website for homebuilders. You might look at it to see if any seatframe and material wil work for you.
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Old 11-07-09, 08:05 AM   #7
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A LWB with rear suspension would probably be as comfortable and easier to find. Also consider using fat tires at moderate pressures, they take a lot of the edge off bumps.
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Old 11-07-09, 08:18 AM   #8
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Some recumbent riders find that a fleece -- the real deal from a sheep -- is a great cushion.

As mentioned, tire selection and pressure makes a major difference in ride quality.
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Old 11-08-09, 07:43 PM   #9
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Milt Turner does a seat that has two elastomer blocks providing a little suspension on the T-Long and the T-Lite. Never ridden one, but just came across the info this week and thought I'd toss it out there.
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Old 11-08-09, 07:59 PM   #10
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suspension, mesh seat, LWB

Bokes,

There are bikes that have lightweight suspensions like the Lightning R-84, but it is a little tweaky and pretty expensive. Thick foam on a hardshell seat is one option, poweroncycling sell 2"thick open cell foam, but as noted in one of the posts above, really thick foam or a really suspended seat can flex a bit and eat up power. Tires can help a lot, something big like a primo comet softens the ride a lot, but the bike has to have the clearance for the tire. Most mesh seats are made of nylon which stretches a bit and some mesh seats are attached to the frame with cord which can be the stretchy cord for the seat bottom to give some compliance and less stretchy cord for the back to not lose power. Long wheelbase is probably better than short wheelbase since when a wheel drops in a hole the seat position doesn't move as much as short wheelbase, but LWB bikes are usually heavier.
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Old 11-08-09, 09:46 PM   #11
Jeff Wills
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Quote:
Originally Posted by Bent Ben View Post
An inflatable chair pad would be more comfy and lighter,IMO.

Plus it can double as a water bladder...how cool would that be to basically ride on a water bed, hahaha
The Thermarest Trail cushion: http://www.rei.com/product/708500 fits perfectly in the pocket that forms the bottom of the Lightning seat. I rode my Lightning for years like this- very nice, but not a lot of suspension.

I don't think a water bladder would work- you'd open the valve and experience "Old Face-Full"

IMO, an Easy Racer Fold Rush would be the machine to try. The long wheelbase will give you some cushion, but the rear suspension really works. I know a couple people that have ridden across the U.S. on them.
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Old 11-08-09, 11:59 PM   #12
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Lightfoot cycles makes a rear suspension LWB. It is called the Ranger. I have one without the suspension. Great bike a little pricy.
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Old 11-10-09, 12:11 PM   #13
bokes
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purplepeople, you maybe saved me a lot of time, I think I'll leave it to the experts, thanks
gcottay, cool about the sheep fleece, I'll might try that
GeorgeVW, thanks for the heads up on that seat, I'll look more into it. That's the kind of thing I was looking for.
Jeff, thanks for the heads up on the Fold Rush. I didn't know about this bent. I'm not looking to tour in remote areas with a complex suspension system, but maybe a simple elastomer system would be reliable enough.
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Old 11-11-09, 10:56 PM   #14
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Jeff, thanks for the heads up on the Fold Rush. I didn't know about this bent. I'm not looking to tour in remote areas with a complex suspension system, but maybe a simple elastomer system would be reliable enough.
If you're in the Bay Area, a trip to Easy Racers should be pretty easy. Watsonville is what... 2 hours away?

Several local riders have been riding Fold Rushes for a couple years. No notable problems. One of them took his on a cross-USA trip and damaged the rear triangle about a week into the trip. He had a replacement triangle shipped to him from Easy Racers and was on his way with minimal delay.
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Old 11-30-09, 04:33 PM   #15
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Kind of...

I recently completed a little customization to a recumbent tadpole trike. This is my first recumbent and, following my initial test rides, I was sold on recumbents in every respect except for the rough ride (rough for me after 25 years of comparatively silky smooth diamond frame riding). My solution was to find a recumbent with the following and perform these customizations:

1) A rear suspension.
2) A 26" rear wheel.
3) Make every seat-frame-to-main-frame connection point able to pivot (even if only a few millimeters).
4) Turn the seat stays leading from the seat frame to the main tube into shock absorbing pistons by unclamping them so one slides freely into the other and adding rubber stoppers inside the seat stay tubes.
5) Place a rectangle of thick rubber between the bottom of the seat frame crossbrace and its attachment point with the main tube.
6) Wrap the entire seat frame in closed cell Neoprene foam (the kind used to insulate water pipes to prevent freezing during the Winter).
7) Installed a Schwalbe Big Apple tire on the rear wheel.

After having purchased a recumbent with the listed requirements and completed the customizations, I barely feel the bumps anymore and the general road vibration of my previous test rides is gone. I'm now rolling along in total comfort aboard a three-wheeled reclining lawn chair.

The recumbent trike I purchased was a TRIKE X 2009 from recumbentusa.com. I'm not shilling for the company; quite the contrary. They leave a lot to be desired in the customer service and technical support areas. However, I'm a do-it-yourself-er with plenty of tools and experience working in a bike shop, so I was confident I could put the trike together and make the customizations without any input from Recumbent USA. If you have similar skills (or know someone who does), the trike, as a trike, is quite good and is easy to customize. I spent 6 months doing my homework before purchasing this trike and it was the only aluminum-framed, 26" rear wheeled, suspended recumbent trike I could find in my price range or ANY price range, for that matter, as aluminum-framed, 26" rear wheeled, suspended recumbent trikes are apparently pretty rare (paid $1400 w/ shipping on eBay).

I'm putting together a webpage with photos detailing my customizations. Unfortunately, it's not ready yet or I would give you the URL.

Good luck, though.

Last edited by Captain Creeg; 12-01-09 at 11:59 AM.
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Old 12-03-09, 10:43 AM   #16
chucky
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Quote:
Originally Posted by purplepeople View Post
There are no production seat suspensions that I'm aware of.

If you're going make your own some advice from someone whose already been there.

1) A poorly designed seat suspension will rob energy as quickly as a poorly designed frame suspension. Problem is that most designs do not take into account the torque placed on each pivot point. In fact, most seat suspensions I've ever seen or tried myself is actually more susceptible to pedal pogo.

2) Suspension has two general functions. Comfort and traction. Off road designs tend to give more comfort as a result of increasing traction for the very large bumps encountered. Road suspension generally cannot give lots of comfort while maintaining traction.... think sports car vs limousine.

3) Good tires provide more bang for buck than suspension.

4) Sometimes a good recumbent seat can more than make up for the lack of suspension.

5) If you still insist on making one, study all of the existing types and understand the compromises inherent in the design. Landmark designs include Alex Moulton (including the damping system of the original Mini Cooper), Horst Leitner (which is a transverse MacPherson Strut) and the Slingshot MTB. Another place to look is in motor racing of all types, where suspensions have often proven to be the difference between win and lose.

ensen.
+1 Only things I'd like to add are:
A. Suspension can also reduce rolling resistance and thereby increase efficiency.
B. The less unsprung weight the better. So a properly designed suspended wheel will be more efficient than just a suspended seat.
C. GOOD PNEUMATIC TIRES ARE SUSPENSION. For light riders a wide supple tire is probably about the best suspension you can get for road riding, although it might not have enough travel for offroading or heavy riders.

These three reasons are why almost all road going vehicles have pneumatic tire suspension. Don't let their ubiquity fool you; Pneumatic tires were originally designed as a suspension system and to this day they continue to be one of the most effective suspension systems ever devised. Therefore I strongly suggest that anyone seeking more suspension first try tuning the parameters of the suspension system they already have.
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