Can FPS rims be run tubeless? - Ducati.ms

900SSDesmo · Mar 26th, 2011, 3:03 pm

Working on an 81' Darmah and notice it has tubes front and rear. Can the FPS rims be run tubeless? I have had Campy's and others that I know are older and ran the tubeless without any problems. Anybody know the deal on the FPS??

Thanks in advance

wdietz186 · Mar 27th, 2011, 9:59 am

You could probably run them tubeless like the others if the wheels aren't porous.But! Keep in mind none of those rims have the bead retention lip that is on rims designed for tubless tires. The lip is there to keep the tire on the rim in the case of sudden deflation such as a puncture or a sharp impact that unseats the bead from the rim. Not really worth the risk I'd think.

Ventodue · Mar 27th, 2011, 12:56 pm

Quote:

Originally Posted by 900SSDesmo

Can the FPS rims be run tubeless?

Yeh, can be done. Quite a few of the Laverda mob (also FPS wheels) run tubeless. But keep Bill's warning in mind: they weren't designed for it. So your risk ...

Ciao

Craig

gadgetguy · Mar 27th, 2011, 8:45 pm

I have same bike and wheels, have done research and +1 on this.
Having said that, you may look into making up for the lack of bead
retention lip by using this:
TUbliss : Go Tubeless With The Ultimate Traction Control System
Used primarily for off road, I don't know effects on high speed use.
Contact the company about that.
When my Avons are done, I might look into it.
The Oscams used on the later '84-85 MHR Mille's were tubeless
and retain the same dimensions as the FPS if you can
get your hands on those.

MitchB · Mar 28th, 2011, 9:56 am

Quote:

Originally Posted by wdietz186

You could probably run them tubeless like the others if the wheels aren't porous.But! Keep in mind none of those rims have the bead retention lip that is on rims designed for tubless tires. The lip is there to keep the tire on the rim in the case of sudden deflation such as a puncture or a sharp impact that unseats the bead from the rim. Not really worth the risk I'd think.

Can you provide a little more detail?

I get that the rim doesn't have the lip - but deflation is deflation isn't it? If the tube is punctured, doesn't the tire deflate and distort the same?

wdietz186 · Mar 28th, 2011, 9:38 pm

Well yes, a deflated tube is a deflated tube and the whole shebang will come off the rim under certain conditions.Punctures are rarely sudden,complete losses of air so you usually have some indication of something being amiss.
Sudden impacts [potholes etc.] can push the bead off the seat area and with the tube exerting pressure on the bead no air is lost but without a tube, Wooosh,Wiggle,BAM!
On a race bike it might be a weight advantage to go tubeless but on a classic,hard to replace not likely to be ridden hard Ducati what is the benefit?
Once you change a tire or two fitting tires without pinching a tube is easy.

machten · Mar 28th, 2011, 10:49 pm

Quote:

Sudden impacts [potholes etc.] can push the bead off the seat area and with the tube exerting pressure on the bead no air is lost but without a tube, Wooosh,Wiggle,BAM!

And fast deflation of the front tyre is not a lot of fun, particularly when using clip-ons. Lots of the Wiggle stuff! (fortunately no BAM for me, but no shortage of butt clenching)

Kev

900SSDesmo · Mar 29th, 2011, 8:20 am

Thanks for the replies. Tubes are the answer. I had not remembered that the bead retention is an issue.. Many years ago when cast wheels were new - I always ran them tubeless and just punched out the tube hole to .423" and machined a flt on the inside for the stem to seal on. This was on race bikes and heat was a big issue - so I dumped the tube.

wdietz186 · Mar 29th, 2011, 8:55 pm

I too must admit to running tubeless on my 77 SS way back when. I had/still have Dymags and raced quite a bit but the tires were most always fresh and pressures checked every time on track. When I read about the different rim configurations and realized what was at risk I changed my errant ways.

Bevel-Heaven · Mar 30th, 2011, 12:28 pm

The red & silver bike in my .sig file photo below has EPM magnesium wheels. They are similar to the FPS wheel in that they are designed to have a tube [no lip on the inside to retain the tyre].

I run tubes on this bike as well as my 900SS with FPS and my spoked SS & GT. I ride my bikes hard, I am not concerned about excess heat or whatever, as riding hard on the street is nowhere near the same as any racetrack speeds etc.

My advice is to run the tubes and be done with it. Safety is key. For you and your bike.