air seat questions

Try it both ways and see which way you like best.

With the single layer air pillow with Miyata foam on top a 16 inch tube
will do the trick as in my 'airseat gallery'
(http://gallery.unicyclist.com/Airseat)

With the double layer 'dogbone air pillow'
(http://www.unicycle.com/shopping/shopexd.asp?id=258) a 20" tube fits.

Play around and see what's most comfy for you.

The double layer dogbone will be softer and more squishy. But it will
feel like an old waterbed and you may have problems keeping the seat
from getting lopsided. The single layer with foam on top will be a bit
more firm, but will feel more solid like a normal seat. The choice of
foam has a big impact on how the seat feels.

--
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I just built an airseat for a friend. Unfortunately, Unicycle.com sent
9 individual bolts, not the "u" shaped bolts that I have on my old CF
Seat. Also these bolts are all flat and round and smooth on the head of
the bolt - nothing to grab onto when you are ready to tighten the
bolts.

With the "u" shaped bolts, you can tighten them from the underside with
the seat fully assembled. The bolts will not spin.

Are these"u" shaped bolts available? Or, should I just go to a hardware
store and get something more workable? Any ideas?

Thx

--
merrill

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The "U" shaped bolts you got were from the old "Made in Japan" Miyata
seats. Can't get that hardware any more. The new Miyata (or Torker)
seats have all straight bolts.

What you got from Unicycle.com are probably 'carriage bolts'
(http://www.allproducts.com/usa/rivetking/p20.html). With the carriage
bolts you drill an undersized hole and then use a small file to file the
hole square so it fits the square shoulder of the carriage bolt. A
carriage bolt in a square hole will not spin.

See this thread: 'seat base instructions' (http://tinyurl.com/57cx4) for
more info on drilling the holes.

--
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merrill said:

*Are these"u" shaped bolts available? Or, should I just go to a
hardware store and get something more workable? Any ideas?*

Joe, I used carriage bolts on my CF job and they worked great. This is
the way to go. As JC notes, you need to get a needle file to turn your
round drill holes into square holes that will hold the carriage bolts.
Two recommendations when you do this:

1) Wear one of those paper cone masks you can get at hardware stores.
Otherwise you'll get miner's lung as you file away.

2) The drill hole doesn't need to be all that much smaller than the bolt
size. I probably could have gone one size bigger on the drill bit, and
as a result I had a lot of unnecessary filing to do. Maybe find a
non-critical part of the seat and experiment. I think the smallest step
down in bit size from the size of your bolt should do the trick.
JC...thoughts on that one?

--
tomblackwood - Registered Nurtz

Tailgate at your own risk.....

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tomblackwood said:

*2) The drill hole doesn't need to be all that much smaller than the
bolt size. I probably could have gone one size bigger on the drill
bit, and as a result I had a lot of unnecessary filing to do. Maybe
find a non-critical part of the seat and experiment. I think the
smallest step down in bit size from the size of your bolt should do
the trick. JC...thoughts on that one? *

As long as the drilled hole isn't too big it will be OK. The closer you
can drill the hole to the final size, the less filing you'll have to do.
It would be a bad thing to drill the hole too big.

I don't know what the ideal drill bit size would be for a 1/4" carriage
bolt. I don't have a 1/4" bolt handy to measure to find out.

Picking the right drill bit size is one area where I would measure and
double-check twice (or thrice) before drilling that first hole.

--
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tomblackwood said:

*Maybe find a non-critical part of the seat and experiment. I think
the smallest step down in bit size from the size of your bolt should
do the trick.*

It needn't be part of the seat :p , anything will do, wood is not
recommended as it will have an apparent size smaller 😠 than the
hole in, say aluminum (which is good, easily available, cheap). Start
with 1/4 and go down in 1/64th increments or numbered bits if you have
them - I use my drill index for a starting point on such things.

If you have a caliper, measure the sides of the square section nearest
the head (it's tapered), as it isn't the threaded section you’re cutting
the hole for. Also, keep in mind that it's tapered while you're
fileing, for a better fit - it should be a -just- snug fit for max
strength.

--
brian.slater - Nellfurtiti, the Wonder Cat

Brian C. Slater
AKA: Snoopy

Ok, I am now officially in my normal state of -advanced- confusion.
Don't try to confuse me, it won't make any difference.

"To not decide is to decide" - undecided
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Yup - they sent me carriage bolts.

Quoted message said:

It would be a bad thing to drill the hole too big.

Too late. I made the seat during East coast Muni weekend in a rush so
that BillyTheMountain would have a seat. I drilled the holes so that
most of the bolts were tight at the square area. However a few were
spinning. I'll try some bolts with a hex head, or phillips head so I
can tighten them better. Obviously I'll need to remove the seat
cover/tube, but it'll work.

The seat did last a four hour ride, but obviously needs improvement to
be durable.

Thanks for letting me know about the extinct u bolts - at least I'll
stop wondering if they can be found.

Also good to know how to do it right, even if too late!

Does anyone happen to have a pattern for the dogbone airpillow or should
I just make my own?

Joe

--
merrill

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merrill said:

*Thanks for letting me know about the extinct u bolts - at least I'll
stop wondering if they can be found.

Joe *

Although the u-shaped bolts are no longer used you can easily fabricate
a resonable alternative. Using threaded rod (available from most
hardware stores) you can cut and bend you own. Be careful when bending
the rod as it may be prone to break at the bend.

I've done this with my last (chinese made) Miyata saddle and it's
holding up fine. With this setup it is impossible for the bolt to
spin.

For more details on this see:
http://gallery.unicyclist.com/Miyata-seat-conversion

-mg

--
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The sun is the same in a relative way but you're older, shorter of
breath, and one day closer to death.
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A couple of other fixes for the oversize hole problem:

Buy an epoxy kit( 5 minute, or JB Weld, etc.). Apply some car wax or a
very light film of Vaseline to the bolt threads, square shank, and
underside of the head to act as a release agent. Mix the epoxy and
apply a small amount on the underside of each bolt head, put the bolt in
the hole and put a piece of tape over it and leave the base sitting
upside-down to cure. The epoxy will mold around the square and keep the
bolts from spinning, but they can still be removed. It will hold better
if you chamfer(bevel) the sides of the hole a little first.

OR

Have someone weld small bars or rods between the bolt heads. Very easy
(for a weldor) and works great.

Scott

--
S_Wallis - MUni Motivated

"I am always doing that which I can not do, in order that I may learn
how to do it." Pablo Picasso
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merrill said:

*
Also good to know how to do it right, even if too late!
*

I saw somewhere in the gallery what I thought was a pretty clever method
of stopping bolts from spinning. The clever mperson in question cut a
notch into the end of the bolt. This allows you to use a standard
screwdriver to keep the bolt still while you use an open wrench to turn
the nut.

Simple but it worked.

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TheObieOne3226 - Judge me by my size, do you?

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Maybe someone could get a run of custom square u-bolts from

http://www.mmsacc-stainless.com/html/u_bolt.htm

Or perhaps there's something standard that would fit.

http://bosunsupplies.com/products2.cfm?product=S0350

Although I guess it's a metric one that's used on unicycle seats.

Joe

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The ones we use arent quite like that as the arch in the back would
probably be too large. Ours are right angles.

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TheObieOne3226 - Judge me by my size, do you?

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