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AlanC

Tyre fitting

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Hi Folks,

Just looking for an easy solution to this problem if there is one.

How much pressure is it safe to use to get a new trial tyre onto the rim?

Rear tyre, tube fitted due to air leaking at the spokes even though a seal is fitted, lots of soapy water used.

Used 70lb of pressure but last bit of the tyre still won't pop onto the rim properly. Tries valve out and in, and tried using the rubbery bead seal thing that should pop out when the tyre is on.

Plan B will be to refit the old tyre if I can't figure it out!

Thanks

Alan

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Normally pop on by 70-80 Pound.

Have you tried bouncing the tyre on the ground while at 70 pound in the location where it hasn't fully seated.

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Nerve wracking, but I’ve gone to 100-110psi briefly when seating the bead on obstinate tires. 

If you have not done this yet, remove the valve core from the stem before inflating. this will allow air to rush in from your compressor quickly to snap the bead into place. A large compressor tank will help here as well; if you’re using an electric pump, mini compressor, or hand pump, that makes things tougher when it comes to recalcitrant tires. Plus, with the core removed, you can repeatedly fill and relax the tire in cycles, gradually working it into place. Inflate! Relax. Repeat. Reinstall the core after the bead pops into place. Then inflate to 30psi with the core in to be sure the tube is settled in well, and then bleed it down to 12 psi or whatever operating pressure you want. 

Also, I use WD-40 instead of soapy water. A tire with soap film will get slippery all over again when it gets wet, and it might slip on the rim. WD-40 is very slippery but evaporates in a couple minutes leaving your bead nice and sticky after it’s mounted. 
 

Where is this coming from, you may wonder? I used to work in a shop where I changed hundreds of tires. 

Edited by PakJeem
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Thank for the replies folks. I was using a proper air line with a big compressor so no shortage of air, and I had the valve core removed too. Thats why I was wondering why it wouldn't pop. But I didn't have the nerve to go to 110 psi. and I didn't try WD40 either. But I did try bouncing the tyre on the ground with 70 psi in it, but it didn't work.

Thanks

Alan

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As Pak Jeem says ^^^

I have used a heavy rubber mallet before now to give the tyre a good whack at the point its refusing to go on, this has worked, along with spraying on the WD40.  Just be careful if you do whack it with a mallet that your head is well clear of the bounce back, trust me I've had a few near misses when not concentrating! You may have to just go a little beyond the 70psi, a little scary I know but if you do it as Pak mentioned it will be fine. I doubt you would need more than 100 psi or so, they do go with a very loud pop at that pressure when they finally go on the rim, and even though I know its coming it still makes me jump!  

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If you have a ratchet load strap that you can run round the outside of the tyre you can tighten it to "spread" the tyre.

The bead should pop as you inflate.

Soapy water or WD helps.

Cheers

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I have also gone to 100 psi many times with no issue.  For safety, I use one of the clip on air valves so I don't have to hold it on the tire.  I have a steel man door on the garage and put the wheel on the outside of the door with me on the inside.  I can then turn up the pressure from the inside until I hear a pop or just give it time.  I can then also turn down the pressure before I inspect.  Even if something catastrophic happens, I should be OK.  I use regular tire mounting lube from an auto parts store. 

I do think bad things can happen.  I once bought a bike that came with new tire but I don't know how new.  I took it to a shop for mounting and got a call that I was getting a brand new tire because something happened during install and the installer broke his wrist.  The tire in question was being saved for the insurance company but I could never get full details.  

    

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I have had a moto tire blow off due to excessive pressure, pretty scary, not sure what the pressure was but the tube was certainly the failure point, blew the tire right back off the rim. I was having trouble with my last set of Dunlop 803's getting the tire to seat as well (with tube) it was around 80psi and left the tire in the shed with the wood stove going while talking to the neighbor outside. We both heard the audible pop of the tire seating itself. I would recommend about 80psi and 30° celsius! 

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Most tyre manufacturers suggest 50psi as maximum to seat a bead.  At 100 or so there is a real risk of the rim failing.  Lots of tyre soap and be gentle.  Sometimes you can leave the tyre a few minutes and it will "creep" into position.  Anything over 60psi and you seriously need to be in another building to the tyre.

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Once the hose snagged on the valve stem and I couldn’t get it off   At 150psi the tube exploded. My ears rang for awhile. Eat protection would have been good, but I was changing a tire!

sounds like you’re doing it right. Try a bit more pressure and lots of wd-40. 

Oh! Did you put some baby powder inside the tire to help the tube slip around inside? Always key. 

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Thanks for all your replies. Made a few calls today, and the general consensus is that I had enough pressure, and just need a ton of proper tyre soap, and a bit of time for the bead to work itself on. Its an old wheel, so more patience will probably help too.

Alan

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how did the tyre come to you, when i was in the tyre game, we used to have issues with some tyres that had been compressed in transit. guys would put a tube in them to get them back into shape first (before fitting).

you could try a bead cheater (a giant air tank with a dump valve)

there was a issue for while with some tyres (IRCs) on some shapes of rims (but i think that was all resolved)

Edited by rabie
still can't spell - gaint--> giant

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24 minutes ago, rabie said:

how did the tyre come to you, when i was in the tyre game, we used to have issues with some tyres that had been compressed in transit. guys would put a tube in them to get them back into shape first (before fitting).

you could try a bead cheater (a gaint air tank with a dump valve)

there was a issue for while with some tyres (IRCs) on some shapes of rims (but i think that was all resolved)

They were usually just shrink wrapped in cellophane.

I have one additional thought for the original poster: heat the tire with a blow dryer or heat gun to soften it up. Then apply liberal WD-40 to both sides, and inflate, relax, inflate, relax, inflate to high pressure, hold it...it should pop right on.

Try softening the tire with heat. Could be the piece you're missing.

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Remember that people have been killed when over-inflating tires to really high pressures, causing them to explode with extreme force.

 

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On 9/29/2021 at 9:13 PM, AlanC said:

Hi Folks,

Just looking for an easy solution to this problem if there is one.

How much pressure is it safe to use to get a new trial tyre onto the rim?

Rear tyre, tube fitted due to air leaking at the spokes even though a seal is fitted, lots of soapy water used.

Used 70lb of pressure but last bit of the tyre still won't pop onto the rim properly. Tries valve out and in, and tried using the rubbery bead seal thing that should pop out when the tyre is on.

Plan B will be to refit the old tyre if I can't figure it out!

Thanks

Alan

what tyre is it, and you're sure its tubeless tyre and rim?

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