Does this uni exist?

I want a 20" wheel, with a fat off-road tire, a flat crown for foot
placement, and a Schwinn style seatpost that uses a bolt instead of a clamp.
If you get a Schwinn, you get the nice seatpost that will never turn on you,
but the crown is angled and smooth and very hard to keep your foot there
when it’s wet outside. If you get a Miyata, you get the nice crown that you
can keep your foot on for 1foot stuff, but it has a clamp that has to be
tightened and will turn if you fall hard. Is it possible to get the best of
both worlds?

Karen,

If you custom-build it, I’d say yes it does.

For your frame, I’d suggest the KH Pro Trials, the KH Trials, the Summit Trials (anyone know if it has pieces for grip on the crown, as the KH frames do?), the Yuni or the Bedford (if you live in Canada, or even if you don’t. A picture of his trials uni here.) Those all have a good crown for resting one’s feet (that said I haven’t tried them all, so feel free to suggest otherwise, those of you who have ridden them).

All of those will fit a nice fat tire, so that shouldn’t be an issue.

For your seatpost desires, I’d suggest to drill your own in the spirit of a Schwinn or use a BMX seatpost clamp. I’m currently using a 3-bolt clamp on my MUni and it is phenomenally rock-solid (pictures here and here). Unicycle.com sells a two-bolt clamp here (which I would think would be very strong as well – reviews anyone?).

Later,
Eli.

Get a good BMX seatpost clamp and you won’t have any problems with the seat twisting on you. You may have to try a couple of different clamps till you find one that fits your frame well. Not all unicycle frames have the same OD on the seattube.

Another thing to check is the inside of the seattube. Some of the Chinese and Taiwanese frames have chrome globs, weld splatter, and other gunk inside. The extra gunk prevents the seattube from getting a good grip on the seatpost. Cleaning out the gunk with some sandpaper will make things better. Oh, and get a BMX seatpost clamp.

How about this one:

http://www.unicycle.uk.com/shop/shopdisplayproduct.asp?catalogid=164

Once you have the seat the right height you could drill it and put a bolt throught it. A good quality seat clamp (not a pressed steel one) should be fine though.

I am relatively new at the uni thing but I have an Onza trials and am very pleased with it. The seat does get knocked around a bit when I continuously dump it on the ground but nothing a good whack with the heel of my hand doesn’t fix. Like was mentioned above, you could drill it and put a bolt in it. I tightened the seat clamp very tight and it made a big difference.

Personally, I don’t worry about it moving, I just put it back when it gets out of line.

To me the splined hubs, great wheel and decent price more than make up for an occational seat whacking. What if you order a new seat and the seat is out of alignment? My KH Velo is slightly off but since the post is infinitely adjustable for 360 degrees it makes no difference to me.

noodle

a decent seatpost clamp will solve the slipage problem,
just don’t use a quick release.

a yuni/nimbus ii frame has a flat top.
and a monty or onza tire is big fat and 20".

if you realy did want a bolt through the seat tube you could drill a hole in the frame and one in the seatpost.

Does this uni exist?

Yes. As has already been explained, you don’t have to skewer your seat post to make it a reality. Good clamps make a huge difference over the stock cheap stuff on low-end unicycles.

Remember, the problem with the Schwinn/Semcycle design is that you only have 1" increments on seat height. If you read any “fit” information for bikes, you will see very loud warnings about making height changes of more than about 10mm at a time. What are the odds that the perfect seat height for you is close to those 1" holes?

A good double-bolt clamp will serve you well.

The GB seatpost replacement really makes a difference too. It won’t warp under the clamp pressure the way some of the stock ones will.

http://www.unicycle.com/shopping/shopexd.asp?id=608