Seat Pan Pain??--Anyone?

I am in search of any suggestions for a cure to the severe pain in my legs that comes from the front edge of the seat pan on my SILVIO CBSV-091. This pan is similar to sciatic nerve pain, in that it radiates distally down the leg to cause an ache in the knee and ankle areas. The width of the front of the pan is hitting the back of my thighs approximately 4 inches below the hip joint. This pain will begin within the first 5 miles of any ride. Pleasure, power and speed, all 3, disappear as the pain sets in and I find myself squirming around on the seat like a restless child in school.

If I could round down the edges after cutting, I think I would cut away a large section from each side of the front of the seat to clear my thighs on the forward/down stroke. Counter-current to recumbent thinking, I have a vision of a standard road bike saddle with the tilt angle adjustable and the existing seat back @ 45 degrees to lean back against. Gasp!!! Yes, it is true I would rather ride on a narrow roadbike saddle than this wide seat pan!

I have moved the stock seat pad forward and back over the pan trying to find a cure, but none yet. With traditional high-racer recumbents the seat can usually be adjusted to fit the rider and by reclining back more the pressure is taken off the buttocks area until comfortable--we don't have this option.

I have reason to believe that if I were shorter (x-seam = 44.5") this might not be an issue, because adjusting the TFT would raise the bottom bracket in an arch and more clearance would be available for my thighs. If this theory is correct, riders my height and taller will be the ones most likely in pain.

If I were giving input on the design of the Vendetta as a time trial bike, seat design would be part of the new features.

Oh BTW, Mr. John T., how does the VENDETTA prototype progress at this time? You are finishing riding season in the southern hemisphere? and we saw a photo of the lovely creation last September at the beginning of warm weather in your half of the world. Hopefully you got a lot of real world testing miles on the proto.

Larry
 
I added some extra cushions on the seat of my Sofrider.
http://www.flickr.com/photos/sykkel-bent/sets/72157603313704669/

This could possibly help but not certain it will be enough to give you more clearance and less pain.
Maybe you could try this before modifying the seat pan?

Peder
 

John Tolhurst

Zen MBB Master
Hello Doc Reyman,

I would insert a second piece of sleeping mat rubber (1/2" or about) in the seat pan cushion and test. Then I would bolster the seat back at the low half to bring my body forward.

Incidently I did both tricks on my Vendetta prototype. Vendetta is faster than Silvio both up hill and down dale. I am happy with the image of the bike also. But I am not yet satisfied with the handlebar ergonomics or the cabling solution - my heart wants internal cables within the handlebar and boom as far as the pivot clamp over the headset.

And I wonder, yes I do, how much farther back I can recline the seat and not corrupt the ridability.

And I worry, yes sir, I worry about what rough chip seal surfaces do. They are not my friend and I would like to imagine a softer lighter rear suspension system than Silvio has on the back, indeed I have imagined it and drawn it but I don't know if the problem warrants prototyping my solution. How much faster would the bike be if I could prevent road vibrations from entering the body, it could be as much as 5% and is a lot to leave behind.

Or should I stop toying and bring the sweet beast to market??
 

WhiteSilvio

Well-Known Member
Doc Reyman wrote: The width of the front of the pan is hitting the back of my thighs approximately 4 inches below the hip joint.
If I could round down the edges after cutting, I think I would cut away a large section from each side of the front of the seat to clear my thighs on the forward/down stroke. Counter-current to recumbent thinking, I have a vision of a standard road bike saddle with the tilt angle adjustable and the existing seat back @ 45 degrees to lean back against. Gasp!!! Yes, it is true I would rather ride on a narrow roadbike saddle than this wide seat pan!
Larry

Hi Larry/Doc Reyman,
When I first started riding my Silvio I didn't particularly notice the seat pan bumping the back of my legs, but over the last 6 months I have dropped off about 6kg and I must have removed some of my "padding" on the back of my thighs!!
Now when I am riding I notice the seat pan bumping on the back of my thighs. Fortunately, I don't get the kind of pains that you describe, but it is really "distracting" and I feel some discomfort. It causes me to shift about on the seat pan to try and avoid the bumping. I have some back problems so I have developed a fairly thick cushion for the back rest which in turn moves me forward on the seat pan, but not enough to clear the front edge of the seat pan.

I too have thought that the shape of the seat should be different, and that there is a reason why DF saddles are the shape they are. I don't think that the seat needs to be anywhere near as narrow as road DF saddles, but it does need to be modified.
I have given some thought to cutting and rounding down the seat pan, and ending up with a shape closer to the shape of that "saddle gel pad" (Trico Painkiller Saddle Pad) that got mentioned in another thread recently. It looked like an old fashioned wide saddle for a DF bike. My initial thought are that this would be somewhere close to an appropriate shape for the seat pan, probably across the entire MBB range of Cruzbikes, maybe even the Sigma too.

Regards,
John R.
PS If you decide to modify the pan let us know how it goes and what you do. Pictures if possible!!
 

gannet

Member
Larry, John R, this is a bit of a worry, given my Silvio has just turned up. One big reason I got it was so my bony old backside would be comfortable!

But, with that relentless human drive to improve things, what can be done to improve the Silvio or Cruzbike generally) seat?
Could the seat base be more concave - well, bum shaped, seeing that is what has to fit!
I used to live near a woodwork gallery, and was impressed by how comfortable a chair could be if the base was shaped - but it was still solid wood, no padding. ( eg the rocker in the middle here )
http://www.bungendorewoodworks.com.au/product_listing/4?page=1

Otherwise, does it make any sense to fit a 'rail' type mount so saddles can be changed? Is there any current DF saddle that would work?

Or what of separate sided / hinged seats like :

http://www.bicycleseats.org/easyseat-bicycle-seat.htm

I don't exactly have a spare frame to chop up and experiment with... and I still haven't finished my build, so no riding experience yet, but keen to see what comes up.
 
Gannet,
Congratulations upon delivery of your Silvio.
I will post more later, but put your fears at rest the seat pain can be eliminated. Yesterday I rode 83 miles, climbing 14 hills, most of them around 4% gradient, and rode my legs to exhaustion and cramps---but the seat and the seatback contact area were not painful. Today I rode 70 miles, flatter but windy and the seat is much improved with different pads. I will elaborate with pictures later. This will be good for DANO also, because he was getting pain from the seat back contacting his backbones--something I too was feeling, but not this weekend.

Larry
 
Gentlemen and Ladies,

I have come to a similar obstacle, however I have a great friend that makes custom Motorcycle seats and is interested in how many of you would be interested in getting a seat bed that would conform to your bottom and relieve those (NUMB-Bum) syndrome problems? If I can present him with enough interest he and I would begin producing these as soon as possible. His Motorcycle seats are custom fit and he uses a special gel that conforms to your sit bones. I am going to have him do this on my Cruzbikes and make them workable for the back pan as well. As soon as I know what these will cost I will let everyone know. Please email me at bikingwizard@peoplestring.com with your interest in seeing what I come up with. The man I am talking about is Rich with Rich's Custom Seats. He can also make any kind of covering for your Cruzbike or Motorcycle.

Again, let me know and I will begin getting Rich set up to begin a production run.

Thanks

Wesley
 

WhiteSilvio

Well-Known Member
WhiteSilvio wrote:
Now when I am riding I notice the seat pan bumping on the back of my thighs. Fortunately, I don't get the kind of pains that you describe, but it is really "distracting" and I feel some discomfort. It causes me to shift about on the seat pan to try and avoid the bumping. I have some back problems so I have developed a fairly thick cushion for the back rest which in turn moves me forward on the seat pan, but not enough to clear the front edge of the seat pan.

I too have thought that the shape of the seat should be different, and that there is a reason why DF saddles are the shape they are. I don't think that the seat needs to be anywhere near as narrow as road DF saddles, but it does need to be modified.
I have given some thought to cutting and rounding down the seat pan, and ending up with a shape closer to the shape of that "saddle gel pad" (Trico Painkiller Saddle Pad).
Hi Wesley,
That's could well be a good offer, however I don't have a problem with sitting on the seat pan for long periods. I do, as I described above, have a problem with the shape of the front "edges" of the pan bumping on the back of my thighs. I think the seat pan should be a different shape. Google (insert favourite search engine here) Trico Painkiller Saddle Pad for an example of the shape I think the seat pan should be.
Regards,
John R
 
Hi Larry

Those are impressive consecutive rides you are doing. Are the mob after you?

I don't have seat pain either, but I'm starting to think that extra padding for my back could be useful. Kim Tolhurst has made a vertical roll of sheepskin fleece for his backrest. I'm curious as to what you did with seat padding / configuration.

My physiotherapist tells me I'm hypo flexible (a "stiffy") and I need to be able to vary my riding position. I've fitted an ICE Trikes hardshell neck rest (pictures later). It would be a miracle if one seat / configuration fitted everyone perfectly, so get out of the hot bath you have been soaking in after those rides, and tell us more :D

And anyone else with pictures of seat backs / pan tinkerings is welcome. Maybe we should start a new thread on seating adjustments?

Cheers

Dennis
 
Hello to all, (especially John R., Gannet, Dennis, DANO)

Here is the first successful remedy for my complaint of seat pan pain.

I still own the Optima ORCA high racer that started me into the recumbent life in 2008. It has a wide (10" X 29") (25cm X 73cm) and long single pad made of open cell foam.
The pad is about 2" (5 cm) thick and encased in a cloth cover.

1780_7773e1f4eac3759fdd36771243fcb1a8


I made a complete replacement of the stock Cruzbike pads and installed this Optima pad.
The loop fastener strips installed on the seat pan and the seat back grip the cloth cover firmly without any additional strips added. Totally different feeling!

1780_b64ef3227dfd7ccef57ec827fb76ebae


The Cruzbike pad totals 1.25" (3.2cm) thick and 40% of that is the closed cell foam. The length dimension over hangs the front lip of the seat pan by 1.0"(2.5cm) or less. Cruzbike pad is on the left in the photo.

1780_ce09358853f40a7616cb570d19d36ae6


Additional modifications are not out of the question. I am thinking of replacing the 2 stock pads from Cruzbike with a single, thicker 1.25"-1.50" (3.2-3.8cm) open cell foam pad insert in the Cruzbike covers.
The closed cell foam portion of the padding is stiff enough to be a significant factor in the pressure I feel on the backs of my thighs. Should be worth experimenting.
Anyone have a good, low cost source for "open cell foam" that a novice like me can cut up in repeated "trial & error" events???!!

Now my extra dilemma is selling the ORCA without a seat pad!!!

Best Cycling to everyone. Larry
 

John Tolhurst

Zen MBB Master
The closed cell foam is too stiff, I think you have put your finger on it. I suggest, go down to the army surplus / camping place and buy a sleeping mat for $10 or $15, try to get a softish one about 3/4" or 20mm thick. Use the closed cell foam inserts from the original cushion set as a template and cut new ones. Reassemble.

When I designed the seat I tested it without foam, but I only really knew the fit to a body my particular size (which is an average of the population, fortuitously). I did tests using a memory foam to identify the pressure points as part of the design information. The softer foam will resolve those last fit questions, and hopefully, Doc, will get you the feeling you have with the thicker foam you have tested.
 
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