Getting a tyre to seat properly?

[ishaw]

So, I've had a day of bike repair. First up my son's mate snaps a cable on his disc brakes, brings it over and I'm fixing that, plus I noticed the rear cable is dodgy and also fouling the discs, fix that too. Then I noticed the horrible rocking from a loose headset, another fix. Add some blingy purple cable ends, just because I could and matched the grips. Off they go back to the track.

An hour or so later I get a call from my son, he thinks he's wrecked his bike, mashed the rear mech and broken chain. I feared the worst and went to collect him, turns out it's just the chain has snapped, well the joining link decided to un join as he landed a jump. Lucky he didn't hurt himself.

I was always a bit dubious about whether the chain was a legit Shimano one, I guess now I know, it's in the bin.

New chain from the stash fitted, re+indexed the gears, noticed rear wheel was out, qr loose so another fix done, then I'm asked if I can fit wider tyres. 2.1s not enough for a 12 year old it seems.

Had some new magic Mary tyres in the garage so thought why not, fitted them but they didn't seat well, that thing where some of the bead just doesn't pop into place.

Took them off, lubed the tyre edges and rims with washing up liquid (fairy, only the best) and tried again. Still they wouldn't seat, even after filling them to 60 psi, no satisfying pop as you usually hear when pressure wins and the jump into place.

So, how do I get these tyres to seat right?

 

[bikeworkshop]

I go to 120 psi.
Wear safety glasses though, and possibly ear defenders.

Of course when you venture beyond the "max psi" rating, you have to take personal responsibility for any unexpected outcomes.

I was told by an extremely respectable pro later in the trade that tyres are tested to 2x the max psi printed on the sidewall.
I have gone with this.

A used tyre with damage seen or unseen is far more risky.

 

[Tootyred]

Second the ear defenders and glasses for this. When they go...its ear bursting loud!

Especially motorbike tyres!

 

[Rotorhead]

I can’t really help but I feel your pain as I had the same thing with 26” Gravel Kings yesterday. Eventually, after multiple attempts, lashings of soapy water and me being exhausted, I decided good enough is good enough. They still spin ever so slightly eccentric but only a little wobble.

 

[Betsy]

Second the ear defenders and glasses for this. When they go...its ear bursting loud!

I saw, well mainly heard, a young kid, maybe 10yrs old blow up his BMX tyre at the petrol station air compressor last week

He was walking around, shell shocked.. i think he'd put £1 in and was trying to get his moneys worth..

When i first bought my Rene Herse / Compass Naches Pass i couldn't get them to seat properly.. the issue was loose tape, it had slight side to side movement within the rim so the tyre beading was sitting on the rim tape around 90% of the circumfrance, then falling off the tape and seating on the rim causing a very slight ovality.. it was the original Mavic rim tape but after much trial and error, i had to cut it off and i bound the wheel in multiple layers of electrical tape which couldn't move.. popped the tyre pack on and it's been perfect ever since.

 

[benjabbi]

Yeah go high and if the bead does start to come off, throw it, it bloody hurts if it goes in your hand.
Sometimes the rim tape has shifted, sometimes the bead sticks on the tape and won't slide into place.
Unfortunately sometimes the tyre's on the smaller end of acceptable tolerances and the rim the larger end and it just won't have it.
Sometimes you can just leave it at 60ish psi for a day or so and it sorts itself out.

 

[ishaw]

Thanks, after leaving it at 60 overnight nothing has changed. It's not the rim tape as the rims are Mavic cross trail which have a solid inner rim due to the spokes screwing into the rim externally.

The bike is ow out being ridden, I've dropped the pressures so they are rideable, hopefully they may seat themselves through use or I'll have to come up with another plan to get them seated.

 

[novocaine]

20psi, push and pull the tyre in the rim to move everything up to where it should be. Then go to pressure.