In your last picture the rider appears to be leaning the frame back to compensate for riding downhill into an obstacle. I don’t ride with my frame back, at least not on a flat surface, and when I climb the frame is leaned forward.
The proof is in the pudding, I have tried riding a completely flat seat position and it rode terrible, then as I gradually tilted the seat back the feel and control improved. I continue to play with seat angle, even trying to push myself to reduce the angle over time, but I seem to be at a sweet spot after a couple weeks, 8-10 degrees depending on the seat base and foam.
Sure, it does vary with whether you are going uphill or downhill or on the flat. It was just a handy picture to illustrate the point. It wasn’t completely flat as you point out- but it was a fairly a shallow dip into the stream. When I’m climbing off the saddle, the frame comes upright, but never tilted forwards. So I would estimate that my frame angle varies between -45 and 0 degrees with respect to a vertical plane, but never +45 or greater than 0.
That’s why I’ve found having the saddle either flat or with a slight downtilt to work well for most situations.
I have just finished this and it is light and stiff, just waiting for Boffy to try out then I will let you know what the verdict is, I like it but don’t have much trials experience.
I agree with uniShark. You get exactly the same effect by tilting the saddle as by shifting the seat forwards and backwards. I’m not at all surprised that Ben prefers a saddle which is slightly tilted up, as that has the same effect as shifting the saddle forwards. Nor am I surprised than Ken prefers a slightly tilted down saddle - looking at the pictures he’s posted it is clear he likes a more rearwards saddle position.
Here are some diagrams to illustrate the point:
flat saddle
saddle moved forwards
extra bit of frame added in red
original black frame removed
unicycle rotated back so frame is upright
As you can see, if you tilt the saddle back and then rotate the frame forwards, what you get is a flat saddle shifted forwards (note that you’ll also want to increase your saddle height slightly). Who cares what angle the frame is at - a point illustrated by my second diagram of a frame type popular with cheap unicycles - what angle is the frame in that?
Thanks for the diagrams. I think I agree with you too.
Another way to look at it is that, regardless of the saddle angle, it will equillibriate to a relatively flat or (satisfactory) position to how you are riding.
What changes is the angle of the frame (which gets adjusted up/down).
On a curved saddle, the same applies, but changing the tilt might also result in one sitting on different parts of the curve.
Still playing with the seat angle, pushing myself to ride with the seat flatter and flatter, riding the ghetto flat seat most because it’s on my muni, didn’t end up squashing a seat over the weekend so instead I shaved down my Freeride foam some more.
I think the foam is very important in getting a particular “feel”. The KH foam is way to thick as it comes, but when shaved down it is a little too firm. I ride without padding in my shorts, so maybe that would change things.
My favorite foam so far is the Nimbus gel pad “old style”.
So far the Flatfish has met or exceeded my high expectations. I got a 40 mile ride in on it last weekend. It took a few stops and tweaking of the seat angle to get it where I think it will stay.
The foam and cover are from a KH Street seat. I still may play a bit with it to get it exactly where I want it. I didn’t glue the foam to the base as I found the cover to hold the foam in place enough for now.
The better support of the sit bones is fantastic. The added benefit is the lower handle and stiffness of the carbon base. It gives me more leverage when pulling up on the handle. The slightly farther reach took a bit to get used to, but the longer reach affords a lot more leverage.
Not only did he make the seat base, he made an awesome seat base to boot!
The biggest thing for me is that Pete got the “flat seat movement” rolling, so now folks can buy ready made flat seat alternatives or even try their hand at making a ghetto flat seat.
I had a standard KH Freeride in my hands last night, and honestly, I can’t believe I rode that torture machine for as long as I did. Now my testes feel great, no rubbing or abrasion outside of what I’d expect from a bike seat.
I think there could be some foam tweaking, maybe making “dimples” for the sit bones vs using overly soft foam, or do like some bicycle seats and mold the dimples into the base.
On my seats I have been maintaining a little rise in the nose, the ghetto seat on my muni has the most with maybe an inch rising from the seat center to the bumper, and the Flatfish on my 36er has less with maybe 1/2" rising from the seat center to the bumper.
For muni I still like having a little rise in the nose, it helps with thigh control in tight turns and through tech stuff.
I ordered a Nimbus Slim seat, should have it by this weekend for round three of the ghetto seat flattening. I’m curious to see what sort of pad they are using, I believe it’s similar to KH slim.
I rode tonight and it wasn’t until I got back home that I realized I have not had crotch pain or a crotch rash since going to a flatter seat, yeah!
The Freeride foam is way thick like Pete said, just cut it down on top, round the edges nicely, you can probably take enough off the center that you won’t need to boost the rear of the foam, that’s how mine workd out. I also thin mine on the sides. It’s easier to cut if the pad is glued to the seat base.
I have a Nimbus Slim (if you mean the one with the awful cover that looks like a bird shat on it). It wouldn’t be ideal for a cover/foam transplant because it is a stapled on cover. I think the eyeletted ones are easier to remove and reuse.
Was thinking of using the KH Slim for my other two Flatfish bases, but not too sure I want the grabby material on top. So I think I’m going get a couple of virgin Naomis for my sacrifice. I really like the slim foam and it has a very tough leathery cover, and comes eyeletted.
Ill post them up when i get home i have ridden 23miles of muni the past 3 days and street and trials on my other flat seat.
My only issue is when you are climbing the front of the seat wants to fall out behind you but its easy to get used to.
The diagrams do help explain what I was trying to say.