I did an airseat conversion on one of the new Miyata seats tonight. This time I used the ReeCycle nylon seat cover from unicycle.com. I found the ReeCycle cover much easier and straight-forward to use than the Roach nylon cover. The back strap and the front grommets and cord made cinching it down an easy task.
I used the Bruce Edwards approach as posted earlier. I made 1/4-20 u-bolts out of 1/4-20 all-thread to replace the back two carriage bolts (coach bolts, UK) and two of the front three carriage bolts, one being the front-most. On my previous conversion I had made some bolt plates by broaching 1/4 inch square holes in sheet metal. The u-bolt approach was faster and required no special tools. On both conversions all of the remaining 8mm carriage bolts are replaced by 1/4 inch carriage bolts because the reinforcement plate on the seats has 1/4 inch square holes punched in it and uses the wrong hardware as delivered.
The other seat I did was also a newer Miyata on which I used the Roach cover. That one had three nuts that would not come out easily. I was able to remove the Miyata cover intact. On the one I did today, five of the nuts would not come off. I even used a tool marker to vibrate each nut vigorously for about 30 seconds to try to loosen the thread-lock compound before I tried to loosen each nut. I had to use the razor blade on that one.
On both conversions I used the largest OD 1/4 inch washers that would fit and 1/4 inch split lock washers. The large OD washers distribute the force of the nut more uniformly than the flanged 8mm acorn nuts did. A cap nut can be put on top of any exposed thread to prevent cuts from sharp edges.
I strongly recommend the Bruce Edwards u-bolt approach and the ReeCycle nylon cover.
I’m really interested in more details about the Bruce Edwards u-bolts. How
did you bend them? How did you determine where to bend them? Are they
all-thread? Doesn’t bending all-thread run the risk of breaking it at the
bend? What about the third bolt on the front?
I may be doing a similar conversion this weekend (if the seat gets here).
-mg
“harper” <harper.7nv9b@timelimit.unicyclist.com> wrote in message news:harper.7nv9b@timelimit.unicyclist.com…
>
> I did an airseat conversion on one of the new Miyata seats tonight. This
> time I used the ReeCycle nylon seat cover from unicycle.com. I found the
> ReeCycle cover much easier and straight-forward to use than the Roach
> nylon cover. The back strap and the front grommets and cord made
> cinching it down an easy task.
>
> I used the Bruce Edwards approach as posted earlier. I made 1/4-20
> u-bolts out of 1/4-20 all-thread to replace the back two carriage bolts
> (coach bolts, UK) and two of the front three carriage bolts, one being
> the front-most. On my previous conversion I had made some bolt plates by
> broaching 1/4 inch square holes in sheet metal. The u-bolt approach was
> faster and required no special tools.
>
> The other seat I did was also a newer Miyata on which I used the Roach
> cover. That one had three nuts that would not come out easily. I was
> able to remove the Miyata cover intact. On the one I did today, five of
> the nuts would not come off. I even used a tool marker to vibrate each
> nut vigorously for about 30 seconds to try to loosen the thread-lock
> compound before I tried to loosen each nut. I had to use the razor blade
> on that one.
>
> On both conversions I used the largest OD 1/4 inch washers that would
> fit and 1/4 inch split lock washers. The large OD washers distribute the
> force of the nut more uniformly than the flanged 8mm acorn nuts did. A
> cap nut can be put on top of any exposed thread to prevent cuts from
> sharp edges.
>
> I strongly recommend the Bruce Edwards u-bolt approach and the ReeCycle
> nylon cover.
>
>
> –
> harper - Gearhead
>
> -Greg Harper
>
> It takes twice the man to ride half the bike.
> ------------------------------------------------------------------------
> harper’s Profile: http://www.unicyclist.com/profile/426
> View this thread: http://www.unicyclist.com/thread/19272
>
I threaded 3 nuts near the end of the all-thread. Then I would put the 3 nuts in a vice and hammer the all-thread over to the desired angle. I then used a dremil to cut the all-thread to the desired length before making the second bend. I took me a couple of tries to get the right lengh when performing the second bend. I would recomend getting more all-thread than you think you will need.
You’re welcome to look at the few pictures in the gallery of the Miyata surgery I performed, pictures are currently on gallery page three called “Yoopers Miyata Seat Conversion.”
I did bend the all-thread cold but only bent each corner once. As with Mr. Ground-rider, I also installed nuts on the thread for the fine-tune hammering of the bends into semi-perfect 90 degree angles. Take a look at the pictures for how Greg and I handled the front-most bolt situation. As for where to bend them, it was trial and error for the first 2 bends. I bought a three foot section of threaded rod so I would have enough for my mistakes.
Greg, thanks for the accolades. ROOT BEER RULES!!!
The all-thread has built in relief grooves all up and down its length. I put it in a vice and made the first bend using a piece of copper pipe as a cheater. Any pipe or tube of sufficient strength and appropriate ID will work. I set the all-thread up in the vice for the second bend and went at it with a hammer, comparing it to the two holes it would have to penetrate in the plastic handle occassionally. I loosened the vice and moved the all-thread as required to make the two ends perpindicular to the central section and spaced correctly to mate the holes in the handle. Cut to length, file a chamfer to accept the nuts and you’re done.
All of the other questions you asked are answered in my original post. I didn’t post photos because Bruce already thoroughly photo-documented his job.