Is a prestaflator necessary to use air compressor to set tubeless tire beads?
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Is a prestaflator necessary to use air compressor to set tubeless tire beads?
So I have these used Dura Ace WH-7850 tubeless compatible road wheels that I’m wanting to set up for tubeless. This is my 1st time at this and so far it has been rocky. I cleaned some old sealant out of the rim track for the tire bead with hot water and a scotchbrite pad.
Then I loosely mounted my tubeless valve - a 44mm alloy one that I got from Colorado Cyclist. I used some silicon grease on the tapered rubber part in order to help it to snug up better. I left the valve loose until I mounted my new Hutchinson Atom 700x23 tubeless tire. I wore leather work gloves in order to roll the bead on without tire levers. After some huffing and puffing it rolled on just fine. I then snuggled up the tubeless presta valve, hand tight.
Next, I fired up my air compressor and mounted my Harbor Freight (schraeder) inflator and mounted a presta adapter onto the 44mm presta valve. I went to shoot some air in there since my air compressor was fully charged at 115+ psi.
No success with seating the bead. Air is running out everywhere but mostly through 2 weep holes in the rim extrusion. I figure the main way air would come rushing out there is if it is coming through the presta valve stem.
i went ahead and used my little Feedback Sports Presta valve remover tool and removed the presta valve. I thought the presta to Schraeder adapter would still work but it threads onto the removable part of the Presta valve which was now out. So I just centered the Schraeder pin over the valve opening and did my best to blast some air in there. Same result. Air rushing out everywhere.
I thought i had had read that you can use an air compressor to seat your tire before adding the potential mess of sealant. I had hoped I could get the bead seated so that I could then introduce sealant.
I was thinking of purchasing a “prestaflator”. Maybe the Park Tools one, or maybe a generic Chinese one. Just wondering if others use these presta valve air compressor inflators in their shops.
Also curious about the 2 rim weep holes on the WH-7850 that is allowing all that air to escape and preventing me from attaining the high pressure I require to snap the beads into place.
Help !!
Then I loosely mounted my tubeless valve - a 44mm alloy one that I got from Colorado Cyclist. I used some silicon grease on the tapered rubber part in order to help it to snug up better. I left the valve loose until I mounted my new Hutchinson Atom 700x23 tubeless tire. I wore leather work gloves in order to roll the bead on without tire levers. After some huffing and puffing it rolled on just fine. I then snuggled up the tubeless presta valve, hand tight.
Next, I fired up my air compressor and mounted my Harbor Freight (schraeder) inflator and mounted a presta adapter onto the 44mm presta valve. I went to shoot some air in there since my air compressor was fully charged at 115+ psi.
No success with seating the bead. Air is running out everywhere but mostly through 2 weep holes in the rim extrusion. I figure the main way air would come rushing out there is if it is coming through the presta valve stem.
i went ahead and used my little Feedback Sports Presta valve remover tool and removed the presta valve. I thought the presta to Schraeder adapter would still work but it threads onto the removable part of the Presta valve which was now out. So I just centered the Schraeder pin over the valve opening and did my best to blast some air in there. Same result. Air rushing out everywhere.
I thought i had had read that you can use an air compressor to seat your tire before adding the potential mess of sealant. I had hoped I could get the bead seated so that I could then introduce sealant.
I was thinking of purchasing a “prestaflator”. Maybe the Park Tools one, or maybe a generic Chinese one. Just wondering if others use these presta valve air compressor inflators in their shops.
Also curious about the 2 rim weep holes on the WH-7850 that is allowing all that air to escape and preventing me from attaining the high pressure I require to snap the beads into place.
Help !!
Last edited by masi61; 12-02-18 at 06:45 AM.
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In a difficult situation, you can install a tube, air the tire up. Deflate. Break the bead on one side of the tire, remove tube. Hopefully the other bead stays more or less seated. Now start over.....with one bead, hopefully, more or less seated already, you're already halfway there when you start, and you can get the tire inflated.
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The weep holes are there to allow air to escape should you decide to use an inner tube. To run tubeless, those holes need to be taped over.
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Dan is right. The system should be sealed. No air should escape. It should stay inflated without sealant.
The suggestion to use a tube first is good. That might help.
Use soapy water to lube the beads. I've had great success with Schwalbe Easy Fit fluid.
The suggestion to use a tube first is good. That might help.
Use soapy water to lube the beads. I've had great success with Schwalbe Easy Fit fluid.
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where do I tape them, internally? I did see a buildup of sealant around these holes & i’m Going to need to investigate further...
#9
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I remove the valve core to maximze airflow into the tire from my airshot cannister. The tire seats to the rim, then I let the air out, the bead stays seated, and I add the sealant through the valve before reinstalling core and inflating.
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As for the valve, I have one of those plastic tipped air blaster attachments for my compressor and it worked fine to jam it in the mouth of the core-removed stem. I’ve also used CO2 cartridges.
I've had one combo of off-center rim and tire where the tire was pretty loose and the rim channel was aligned with the spoke holes instead of centered. The bead seated on the side further from the channel and the tire just fluttered on the nearer side.
I've had one combo of off-center rim and tire where the tire was pretty loose and the rim channel was aligned with the spoke holes instead of centered. The bead seated on the side further from the channel and the tire just fluttered on the nearer side.
#11
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group effort
3 friends holding the wheel & tire might work (LBS Did this last June )
+ the air hose guy, so 4 all together..
+ the air hose guy, so 4 all together..
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I was talking to my LBS mechanic yesterday about this and he thinks that the round, cone shaped tubeless presta stem is incompatible with the concave rim bottom of these narrow, early road tubeless rims. He said that I could experiment with trying to shave or file the valves into a shape that would mate up better to the inner rim profile.
I ‘I probably will just use the correct valves and start over again once I have the valves installed. I definitely do not want to introduce any sealant until the bead is fully seated on the rim. I understand there will likely be some leaks but hopefully the tire will begin to start being able to hold some pressure at that point.
I ‘I probably will just use the correct valves and start over again once I have the valves installed. I definitely do not want to introduce any sealant until the bead is fully seated on the rim. I understand there will likely be some leaks but hopefully the tire will begin to start being able to hold some pressure at that point.
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For me the valves have been the problem not the tire. I have used both the cone shaped ones (Stans) and rectangle type (Giant). Have had limited success with both. On a couple of my rims I had a small leak showing not at the valve stem but in the spoke holes near the valve ( used water test in laundry tub).. So. air was getting into the rim channel not by a thorn rim tape but by bypassing the valve stem. The fix for me was a little RTV on a toothpick around the valve stem. Works every time. But to the OP's original ? for me I have both an air compressor and an Airshot in the my shop. I prefer the Airshot for mounting the tires on the rims Works great.
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Tie a piece of paracord around the circumference of the tire (in line with the tread). This will shrink the space for air to go and seat the bead on both sides. If that doesn't work you can do what I do when I have to seat the bead on a tubeless motorcycle tire in the sticks. Spray a LITTLE starting fluid inside the tire and light it with a lighter. The combustion will seat the bead on both sides.
Last edited by nomadmax; 12-03-18 at 06:25 AM.
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I had those rims. The weep holes on mine were for the area between the rim and the carbon "fairing". The rim itself has only one hole - for the valve. I had to replace the rims on mine after less than a year. They were badly corroded and had many small holes in the rim from the corrosion - causing them to leak air badly, of course. Shimano said no to warranty because I used sealant - Calfee Latex. I had them repaired and sold them. I would use the Shimano valves. I find that the area right next to the valve is where air leaks the worst making seating the beads impossible. Try working the beads down the the bead seat carefully then inflate with the compressor.
One other thought - if you are seeing sealant around those weep holes, look for corrosion on the rims. Those holes should not show anything. They are really to allow moisture to escape.
One other thought - if you are seeing sealant around those weep holes, look for corrosion on the rims. Those holes should not show anything. They are really to allow moisture to escape.