Homemade Tubeless spoked wheels

[Travman]

I found this thread interesting.  This guy uses silicone to make his Sport Classic wheels tubeless.  The benefits include easier roadside flat fixes and increased tire possibilities. 
http://www.ducati.ms/forums/showthread.php?t=43414

For those that don't want to read the whole thread:
"I snugged up all the spokes until they had the same amount of threads showing, then torqued them up pretty high to pre-load them. Next they were mounted back on the bike, and I trued them by mounting a dial indicator that I would move around to check for roundness and side-to-side measurements. Once that was done, they got the same sealing process I used on my steel wheels, but I only used 1 and a half tubes of silicone this time. Process: Clean/degrease everything. Plug valve stem. Put sealant in all nipple valleys, let dry 24 hrs. Add layer of sealant spread with a putty knife, let dry 24 hrs. New layer, spread, install rim band, then a final layer covering all edges pretty liberally, and dry 24hrs. Remove stem plugs, and go get some new tires!"

[aaronb]

"I snugged up all the spokes until they had the same amount of threads showing, then torqued them up pretty high to pre-load them"

i hope he knows what he is doing...

otherwise it all makes sense, lots of sealant and a liner.  sure. 

[Howie]

He can be the guinea pig.

[Speeddog]

He can be the guinea pig.

+1 

[Travman]

He can be the guinea pig.

He mentions he had done the same thing before with his stock GT1000 steel rims.  This time he was upgrading to the aluminum rims from a Sport 1000.  So this is round two for him. 

[Roscoe]

This has been done by the supermoto guys and seems to work fine. And tubeless also means less rotating mass, besides easier roadside fixes.

[Speeddog]

Well, if I *had* to have a flat tire, I'd rather wrestle a 'tard than a SC.

What did he do for a valve stem?

[Norm]

I've done it before and if the spokes are a tight fit thru the holes, it works well. If the spoke holes are a bit lose, it's tougher and I've spent a few times on the side of the road waiting to be picked up.

[BastrdHK]

Is he really dropping any rotating mass with all that silicone vs. a tube?  Only have experience with bicycle tubes.

[DarkStaR]

Is he really dropping any rotating mass with all that silicone vs. a tube?  Only have experience with bicycle tubes.

I like the look of the SC wire wheels, but they are such a burden on the bike.  Weight and clearance issues.

2 piston calipers up front.  Most 4 pistons calipers will not clear the spokes without modification. 
1 piston in the rear.  The 2 piston calipers will not clear the spokes. 

[Smokescreen]

they do look cool though don't they.  Although, given a choice, I'd prefer those really thin spoked single sided Carrozerrias personally...
W

[Raux]

ok, had a thought about this. i've seen the supermoto rims for sale with spokes.

wonder what rims would fit on the 696. and how would it look?

[rule62]

This guy is known as "the mad scientist" here in Phoenix.  He knows what he's doing.  Saved a bunch of weight compared to tubes.  Hasn't lost a PSI yet.  The mods on his GT1000 put the b in subtle.  There are so many, but you've gotta know what you're looking at to see most of them.  It's absolutely amazing.

[Dietrich]

Hey guys!  A few of us have sealed our Sport Classic wheels this way, and lacing/truing isn't really that hard.  (Why do so many people think their bike is going to spontaneously combust if you do your own work and a little fiddling?)  Anyway, I have almost 25,000 miles on the GT with the wheels sealed like this.  I did have one mishap that I think was due to a material incompatability.  Here's a copy of a couple recent posts I put on ducati.ms:

Just thought I would chime in here.  I owe it to you guys to let you know about a little trouble I had.  I sealed my steel wheels that came on the GT with GE Silicon II "Our Very Best" metal formula, and it worked great.  Never a problem, in fact they held air way better than the tubes did. 

When I built up the alloy wheels that I got from LA-DUC I used the same process.  But this time the silicon didn't stick.  I had a tire mounted in Albquerque when I wore mine out on a trip, and I don't know if the shop nicked the sealant or what, but I barely made it back into Phoenix.  Luckily it held air for about 400 miles....I rolled into my garage on an almost flat tire (but after 1500 miles I wasn;t stopping ).  So, I had the tire removed and sealed it up again, this time paying extra care with cleaning, etc., but used the same product - GE Slilicon II.  The first ride I made it about 20 miles until the rear went flat.  Got towed home, pulled the wheel, had the tire removed, and this time the ENTIRE BAND of cured silicone and the encapsulated stock rubber rim band came off the wheel in ONE PIECE.  It didn't even try to stick.  I'm pretty sure it had something to do with it just not working well on the aluminum rim.  I didn't have much cleaning to do because it all came off in one piece, you could even see the threads from the spoke nipples, perfectly molded. 

The good news is that both times I lost air it was a very slow leak.  No blow outs, or quick loss of air.  I've had enough flats to know what was going on, and even rode on the low tire for a few miles to get to a station, etc.  I ride so often out of town that being able to fix a flat on the road is a huge plus for me.  I have done this at least twice since sealing the wheels and both times I was back on the road in a matter of minutes with a plug kit.  The weight savings is very noticeable, and the tubless tire (which even the stock ones are really) handle a lot better without a tube inside them.  It's still a very worthwhile mod for me, and I feel very safe with it having done over 20,000 miles between the two sets of wheels I have sealed, in all sorts of ambient temps, touring, and including two track days.

I did some research for a better product and found a marine grade adhesive sealant by 3M, "3M 5200".  I guess they use it to seal and glue aluminum boat hulls together, so I figure it would be good enough to hold in a little air.  I found it at a local marin chain store called West Marine.  I got the slow cure stuff so it took more than a week to be ready to mount a tire.  It's messy.  I was able to clean the uncured stuff up easily with a little acetone.  Wear gloves.

Here's my latest process:

1. Remove tire, tube, and rim band (rubber strip over the spoke nipples).
2.True the wheel with a spoke wrench for both side-to-side and up-and-down.  I mount a dial indicator in many different positions with the wheel mounted on the bike and get it the best I can.  Get a proper spoke wrench for this.  Only turn a little at a time, no more than 1/4 turn at a time until it's as close as you can get - there are variations in the shape of the rim itself where it is welded together.
3. Clean and degrease the rim and spoke nipples as best as possible.  I use acetone.
4. Install a tubeless valve stem. Then plug the stem with a bit of tape twisted inside the hole from the inside.
5. Apply sealant to spoke nipples only, work in each "well" with a putty knife and make sure there are no bubbles. Let dry overnight.
6. Add an even layer of sealant, spread around the entire wheel with a putty knife as even as possible. (1/16" - 1/8" thick). Let dry overnight.
7. Degrease and clean the rubber rim band.
8. Add another layer of sealant, spread evenly.  Re-install the rim band over the new layer of sealant.  THIS IS MESSY!  Press the band down to make sure the sealant is even and to reduce bubbles. Let dry overnight.
9. Add another layer of sealant covering the entire rim band and sealing the edges.  Spread as evenly as possible.  Let dry at least 24 hours before mounting a tire.  48 hours is better.
10.  Have tire mounted and balanced. 

I have never needed much weight to balance the wheels, in fact less than with the tube.   This 3M product is working great, to the point that I don't really check the pressure around town, just kick the tires and ride.  I check it every couple weeks if I'm heading out of town or on a longer ride. 

Hope that helps if anyone wanted more info, or is trying to make a decision.  It's something you have to think about and decide for yourself.  I'm not pushing it, just sharing my own experience.  If I had the cash it would probably be Alpinas for me.  Black and silver...

and some more info...

I re-laced a set of wheels off a Sport 1000 with stainless steel spokes/nipples and found it easy-peasy. Every spoke is the same length, for the front & rear wheel and drive/non-drive side - every spoke. The lacing pattern can only go together one way due to the way the hubs are drilled and angle of the holes in the rim. If you take your time and maybe take some "before" pictures/notes, the lacing is easy. I mounted the wheels back on the bike without tires for trueing and then mounted a dial indicator in several different positions to get the side-to-side and up-and-down runout dialed in. You do need to have an understanding about how turning a spoke nipple affects the movement of the rim, and only turn things 1/8 to 1/4 turn at a time. The weld where the rim is put together is out by more than 1mm, so I tried to check from teh inner lip of the rim where possible, but still, there is some variation...it only gets so good. I'm sure there are some articles on the web about how to true a wheel. It;s really not that difficult unless you just are not very mechanicaly inclined at all, but then I expect you would be taking it to an expert anyway. I have never laced a wheel from scratch, but did work in bycycle shops for a few years, so have trued many wheels.

The tricky part is the tension. I think Buchanens (sp?) where I got the spokes had a guide for torque. I found a couple articles online as well. They also supply some oil that you need to dip the threaded end of the spokes in during assembly to help ease the threading of nipples and even out the torque readings. Supposedly the oil dries out over time and helps hold things in place also? I think. Anyway, I was able to buy a double ended spoke wrench from the local Cycle Gear (chain store) and it just so happend that my 1/4" drive inch/pound torque wrench fit right inside the unused end. I just had to measure the distance to the open end of the spoke wrench and convert the torque readings. The problem I had was my wrench didn't go low enough. So..., I winged it. My wheels are holding up great with over 10,000 miles on them since the build, no additional trueing required.

Best of luck if you give it a go!

[aaronb]

(Why do so many people think their bike is going to spontaneously combust if you do your own work and a little fiddling?)  [/b]

sorry about the spoke comment, i didn't click on the link and just took the out of context quote.  i didn't realize you built the wheels and were just describing the process.  i thought you just reefed down on the spokes in an attempt to make a metal on metal seal or something.   

i have laced countless (bicycle) wheels in my bike shop days.  i always found sitting at the truing stand for an hour or two to be quite therapeutic. 

btw, i love your gt.  what's going on with the headlight, looks interesting.