mikethe

Hi,
I used good tubeless conversion kit, tires, watched all the how to's and did the job pretty carefully and thoroughly.
However, after inflation, it slowly runs out flat after 2-3 hours.
Inspecting I can't see distinct places of leakage.
So, I wonder - Can it be that actually the Fulcrum racing 900 rim brakes version, can't be converted to tubeless?
Thanks,

shelbyfv

Yes, this is correct. https://www.fulcrumwheels.com/en/sup...-en/racing-900

vespasianus

I would NEVER recommend using a rim not designed for road tubeless for road tubeless - even using tubeless road tires.

Trying to convert a non tubeless rim to tubeless is a recipe for absolute disaster.

WhyFi

For the most part, I'd agree with you, but it really depends on why the wheel isn't designated for tubeless use.

If the rim doesn't have the correct tubeless rim bed profile, I'd agree with you 100% - don't do it.

However, I have wheels that *do* have a tubeless profile but aren't designated as being tubeless ready, by the manufacturer, only because the seam isn't welded and airtight. In this case, I was just careful with the rim tape width and application - they mounted and sealed up just dandy and have been problem-free for six years or so.

So yeah, for the most part, I wouldn't advocate conversion, but there are some odd cases where the knowledgeable can use their judgement.

mikethe

So that was my problem: I mistakenly assumed "to be ready" means only taping.
Aftermath, I can tell that "generally" speaking a tubeless tire fitted flawlessly, but probably that's not enough for actual "correct tubeless rim bed profile".
Practically, I can tell, I was able to ride up to 60km/h incl. cornering-that indeed fell strange (but I assumed maybe new tires etc.), but in the end, yeah, after 3 hours slowly flat tire...

WhyFi

This is what the rim profile should look like -



Most tubeless rims will also have a little bead retaining bump/ridge on the inside portion of the "bead shelf," next to the dropped center channel.

shelbyfv

In the specific case of these wheels, the Fulcrum description of "Tyre Type" is "Clincher." For the disc version, Racing 900DB, "Tyre Type" is shown as "2-Way Fit Ready (for clincher and tubeless ready."

mikethe

Yes-that's exactly the confusing part: There is a description for the DB version, but none for the RB version. So I simply assumed it's the same as for the DB version.

mikethe

Now we are talking: Yep, mine is actually the right one - with the dropped channel.
So what's going on here? Might be something else preventing from being ready for tubeless conversion?

shelbyfv

The link in post #2 goes directly to the description of the rim brake version.

WhyFi

Hard to say - you'd have to see if you can get an answer out of the manufacturer. Not sure how easy that would be with Fulcrum. It may be that, like my wheels that I'd previously mentioned, the seam wasn't welded, as a cost-saving measure, and so it's not as airtight as they'd like.