Can I Fit Tubeless Tires to Factory Cast Wheels?

[Guzzi_Don]

I am due for new tires soon to my 850-T4 and at present have tires fitted that also have tubes inside them.

Can I fit tubeless tires to the factory cast wheels or were they not made to have tubeless tires fitted?

If I can fit tubeless tires are there any suggestions as to what I should fit?

Thanks

[Guzzi_Don]

Can you post a pic of the wheels?  At that age they could have been replaced with anything.

I dont have a picture handy at the moment, but they are the same wheels that came standard on the LM2.

[Guzzi_Don]

OK here is a picture of the cast wheels on the bike. A 1981 850-T4 - naked.



Thanks

[fotoguzzi]

yes, you simply need to go to hardware store and get a tank valve, it comes with a thread tap. you tap threads into the existing hole in rim.. from inside out, don't run it completely through so it is slightly tapered (from the inside). you might need teflon tape to seal it, I didn't.
some will say the bead lip on your rims was not made for tubeless rims..
 Many have ridden thousands of miles anyway, I never heard of any problems with the tires staying locked on rim.
I used Pirelli Sport Demons.

[centauro]

Don, my 1984 SP 1000 is set up just like yours, and has the same wheels. Pretty much all motorcycle tires are of the tubeless design these days, as they work with or without tubes, on the proper rims. These wheels, however, were really designed to have tubes, but  I suspect that in the early 80's tubeless tires were still somewhat of a novelty, and cast wheels were coming in fashion.

Several members have had no problems installing sealed valve stems and run tubeless tires, and I plan to do the conversion at the next tire change, as well.

[charlie b]

I just did my T5 and have had no issues.  My rims look the same as yours.

And a thanks to everyone in here who commented on previous threads on this topic.  If not for all of you I would not have tried this and would still be running tubes.

FWIW, I just got the tubeless valve stems with the rubber washers on both sides (from revzilla when I got my tires), but, you might want to consider going the same way as fotoguzzi.  I had to turn down the inside portion of the valve to fit the recessed portion of the rim.  If you use fotoguzzi's method this is not an issue.

Here are the stems I used
http://www.revzilla.com/product/chrome-tubeless-valve-stem

charlie

[fotoguzzi]

to put credit where it's due, I think I got the tip from Mike Tiberio.
many years ago.

[mtiberio]

Use 1/8" NPT (tapered pipe thread) tap. Hole in rim is already right size. As suggested, run tap from spoke side of cast rim toward tube side. Dont go too far, you dont want hex of tank valve bottoming on rim, you want tapers to lock. Use teflon. Odds of tire jumping off rim after blow out is no higher than if you ran a tube, and of course, odds of blow out are much less if any with tubeless. Ran this set up at 147mph at Daytona. YMMV

[fotoguzzi]

Unless there is something odd about the valve hole, a standard euro-type tubeless valve should fit the rim.  I get mine from kurveygirl.com.




If there is something odd about it --- nevermind.   :D

there is, the inside of the rim (tube side) has a half concave curve not a flat base for that nut to seat against.

[Triple Jim]

Actually tubeless motorcycle tires were getting halfway common by 1980.  It was about 1979 when I got a pair of Lester wheels for my H2 that were made to run tubeless.  Unlike early Lesters, they have a small raised ridge between where the tire beads seat and the drop center part, so if you lose air pressure the tires tend to stay put.  It makes them a bit tougher to dismount, but not a big problem.  I assume in general, cast motorcycle wheels that were made to run tubeless have that raised ridge.

[gwb_mg]

Contact Harper's, they have the proper valve stems (no mods needed) and they are inexpensive. I had the same wheels on my Converts and ran the Bridgestone Spitfires with good results.

[Guzzi_Don]

Thanks Charlie, that is really useful info.

[Guzzi_Don]

Use 1/8" NPT (tapered pipe thread) tap. Hole in rim is already right size. As suggested, run tap from spoke side of cast rim toward tube side. Dont go too far, you dont want hex of tank valve bottoming on rim, you want tapers to lock. Use teflon. Odds of tire jumping off rim after blow out is no higher than if you ran a tube, and of course, odds of blow out are much less if any with tubeless. Ran this set up at 147mph at Daytona. YMMV

I don't want to appear ignorant but what is a "tank valve"?

[Guzzi_Don]

Contact Harper's, they have the proper valve stems (no mods needed) and they are inexpensive. I had the same wheels on my Converts and ran the Bridgestone Spitfires with good results.

Thanks FG and GWB I am getting some really useful information out of this thread.

Thanks All.

[fotoguzzi]

I don't want to appear ignorant but what is a "tank valve"?

air compressor valve, google is my friend!

https://www.google.com/search?q=tank+valve&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

[Guzzi_Don]

air compressor valve, google is my friend!

https://www.google.com/search?q=tank+valve&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

OH!! I see.

[dilligaf]

 :+=copcar Photo.  I also did not know what a tank valve was.  Thanks for the link.  The only thing that is stopping the valve from blowing out are the threads.  :+=copcar  I know you haven't had any problems but me, I wouldn't take the chance. We are talking steel into aluminum, dissimilar metals and the galvanic action will deteriorate the threads over time.  I sure the tank valve are designed for steel into steel not steel into aluminum under pressure.   :BEER:
Matt

[Guzzi_Don]

:+=copcar Photo.  I also did not know what a tank valve was.  Thanks for the link.  The only thing that is stopping the valve from blowing out are the threads.  :+=copcar  I know you haven't had any problems but me, I wouldn't take the chance. We are talking steel into aluminum, dissimilar metals and the galvanic action will deteriorate the threads over time.  I sure the tank valve are designed for steel into steel not steel into aluminum under pressure.   :BEER:
Matt

That's an interesting point of view Matt,

I will have to mull over what you have said and absorb it before making my mind up what to do.

Thanks

[fotoguzzi]

then I would go with this,

Contact Harper's, they have the proper valve stems (no mods needed) and they are inexpensive. I had the same wheels on my Converts and ran the Bridgestone Spitfires with good results.

[dilligaf]

 :+=copcar  Teflon will slow down the  galvanic action but by how much I have no idea.  It's a nice clean conversion - just not sure I would take the chance as the corrosion to the threads can not be monitored.  :BEER:
Matt

[mtiberio]

:+=copcar Photo.  I also did not know what a tank valve was.  Thanks for the link.  The only thing that is stopping the valve from blowing out are the threads.  :+=copcar  I know you haven't had any problems but me, I wouldn't take the chance. We are talking steel into aluminum, dissimilar metals and the galvanic action will deteriorate the threads over time.  I sure the tank valve are designed for steel into steel not steel into aluminum under pressure.   :BEER:
Matt

Yes, but at speed, centrifugal force is keeping the tank valve in....   8^))    (while true, just kidding as a safety net)


Also, most of the tank valves I have seen are chrome plated brass. So you are talking galvanic action between a cupric alloy and aluminum, not steel. Plus, once oxidized, aluminum will form an oxide that does not continue to erode. I sincerely doubt this is as bad as a steel/copper union in your house plumbing which will corode until you have a leak. There you have a medium which is continually scouring the junction and removing any protective oxide coating... Here, the junction is protected...

[charlie b]

I agree.  And galvanic action with chrome/brass and Al will be very slow.

And, if the threads do give up you can always get one of the rubber washer types  :)

[Guzzi_Don]

then I would go with this,

OK then Mr Harper here I come -- for a couple of your valve items.

thanx

[Stevex]

Looked at the valve from Harpers and I can source a similar one in the UK.
Take it this is the one mentioned:

 http://www.harpermoto.com/tubeless-valve-stem.html

Bearing in mind the concave shape of the internal surface of the Guzzi wheel,
does the rubber seal sit nicely in place without the nuts being done up excessively tight?

[fotoguzzi]

 http://www.harpermoto.com/tubeless-valve-stem.html

Bearing in mind the concave shape of the internal surface of the Guzzi wheel,
does the rubber seal sit nicely in place without the nuts being done up excessively tight?

I don't have a rim too look at (accept in my memory) but I don't think so..

[gwb_mg]

Looked at the valve from Harpers and I can source a similar one in the UK.
Take it this is the one mentioned:

 http://www.harpermoto.com/tubeless-valve-stem.html

Bearing in mind the concave shape of the internal surface of the Guzzi wheel,
does the rubber seal sit nicely in place without the nuts being done up excessively tight?

As mentioned I have used these on my Converts in addition to my current Cali II Auto, all three had the OEM alloy wheels.

[Guzzi_Don]

Looked at the valve from Harpers and I can source a similar one in the UK.
Take it this is the one mentioned:

 http://www.harpermoto.com/tubeless-valve-stem.html

Bearing in mind the concave shape of the internal surface of the Guzzi wheel,
does the rubber seal sit nicely in place without the nuts being done up excessively tight?

Can someone from Harpers contribute to this thread and verify that the valve they are advertising will fit and do the job?

[dilligaf]

Yes, but at speed, centrifugal force is keeping the tank valve in....   8^))    (while true, just kidding as a safety net)


Also, most of the tank valves I have seen are chrome plated brass. So you are talking galvanic action between a cupric alloy and aluminum, not steel. Plus, once oxidized, aluminum will form an oxide that does not continue to erode. I sincerely doubt this is as bad as a steel/copper union in your house plumbing which will corode until you have a leak. There you have a medium which is continually scouring the junction and removing any protective oxide coating... Here, the junction is protected...

I am going to say this as politely as I can but I just don't think you know what you are talking about. Sorry.

I agree.  And galvanic action with chrome/brass and Al will be very slow.

And, if the threads do give up you can always get one of the rubber washer types  :)
  

pely  

The stem is going to blow out do to the sudden increase in pressure when you hit a bump in the road a speed.  Tire pressure is going to decrease very quickly and you are going to be in for a ride.  With luck the tire bead will remain seated.  As stated in a previous post this is a very clean conversion, but now that I know what a tank valve is, I wouldn't trust it.  There is a reason this system is not used through out the industry.
:BEER:
Matt

[charlie b]

The rims in question have a recess cast so there is a flat spot for the rubber washer to seat against.  And, no, it doesn't take a ton of torque on the nut to seal it.  The only issue is the size of that recess is not very big.  Like I said above, I had to turn down the dia of the valve 'flange' to fit that recess.

[mtiberio]

I am going to say this as politely as I can but I just don't think you know what you are talking about. Sorry.
 
The stem is going to blow out do to the sudden increase in pressure when you hit a bump in the road a speed.  Tire pressure is going to decrease very quickly and you are going to be in for a ride.  With luck the tire bead will remain seated.  As stated in a previous post this is a very clean conversion, but now that I know what a tank valve is, I wouldn't trust it.  There is a reason this system is not used through out the industry.
:BEER:
Matt

Nothing you have said or the manner in which you have said it conveys to me you have any expertise in this area. You learned about tank valves 2 days ago and now you are an expert? Do you know chemistry? I was in the top of my class as a chemistry major at U.Mass. Do you know physics? I went on to study Physics in grad school, and have worked in advanced research for over 35 years. Can you calculate the galvanic response between bronze and aluminum? (about .5 volts by the way, not that it matters here). Can you use boyles law to calculate the rise in pressure due to hitting a pothole? Did you check to see if that pressure was higher than the design pressure of the valve? Do you know how to calculate how strong a thread is? Have you stopped to consider that even if you could hit a bump capable of expelling the tank valve, you would have bigger issues than a flat tire?

And most importantly, do you have over 30 years experience using tank valves in Guzzi wheels? Without a body of experience or the intelligence to put them to rest, your fears might be justified, but seriously scores of these wheels have been converted, millions of miles covered, hitting bumps and potholes, raced, crashed, bent, straightened, welded up, raced again. Some of us without a body of knowledge to go on, risked our lives to create this body of knowledge. It is irrefutable. You can choose to ignore it or not believe it. Fine, go away and shut your mouth, but when you say "don't think you know what you are talking about. Sorry", you got that half right, you are a sorry excuse for an engineer.