How much air to seat a tire bead.

The tires I put on the Polaris were labeled with a not to exceed pressure of 25 psi to seat the bead. Car tires aren't.

I just did a set of Toyo R1Rs for a friend. I could not get the beads to seat. After multiple attempts, flipping the tire on the wheel, and re-lubing the entire bead, I eased up on the pressure until it finally popped. It took 90 psi to get the bead to seat. The tire is rated for 50 psi. I was nervous as hell doing that.

Is it normal for a tire to take that much pressure to seat? Seems kind of high to me. 

It's a mix of tire and wheel, 90psi would make me a bit nervous as well. I recall a set of AMG wheels and tires requiring over 100 psi to seat!

https://www.youtube.com/embed/N45KcCsBYmcHow about some fire? 

dmack 15" rally tires warn on their page that they can take over 140 psi to seat.

https://www.dmacktyresusa.com/_p/prd15/2636937811/dmg2-195-65-15%22

Yeah I hate it when I do those.  Most tires I have done take much less pressure than those.  What type of lube are you using?

Toyman01 said:

The tires I put on the Polaris were labeled with a not to exceed pressure of 25 psi to seat the bead. Car tires aren't.

I just did a set of Toyo R1Rs for a friend. I could not get the beads to seat. After multiple attempts, flipping the tire on the wheel, and re-lubing the entire bead, I eased up on the pressure until it finally popped. It took 90 psi to get the bead to seat. The tire is rated for 50 psi. I was nervous as hell doing that.

Is it normal for a tire to take that much pressure to seat? Seems kind of high to me. 

 

Every car tire I've seen said do not exceed 40psi.  Which is laughable, as many take 60psi or more.

One of my Black Rocket rally tires debeaded at Nationals last year and it reseated at 15psi.  Another one of my Black Rockets debeaded last month and it took about 55psi.  (I've been running BRs since 2014, and these were the extent of all of the debeads they have had.  Lesson:  Don't rallycross a front drive car if you don't want to get good at reseating tires)

One of our locals had some rally tires (I'd like to say Dmacks, but maybe not) on I-forget-what wheels and the tire shop had them at 120psi and they still wouldn't seat.  So he ran them like that at 30psi or so.  They never debeaded despite being unseated a quarter of the way around or so...

IMO, if it's not seating by the sidewall spec, I'd want that thing in a cage in case of wheel or tire failure at high pressure. 

For rallycross reseating, I've seen a ratchet strap around the tire make it easier to re-seat, as it can push the beads mostly into place.  Helpful especially if you can't get air into the tire fast enough. 

Also, make sure you pull the valve core if things aren't seating easily.  Getting it up to pressure faster helps sometimes. 

If you haven't used carb cleaner and a lighter or a cheetah.... you haven't lived.

ive done a tiestrap around to bring the beads closer works ok but not great.

Runflats also have a tighter fit around the beads. The last set i mounted i 'couldnt' seat myself (as in i went as high as i was comfortable with and it didnt work) so i took them to discount and they had to relube them and air them up to 90 psi repeatedly to get them to seat. 

rslifkin said:

IMO, if it's not seating by the sidewall spec, I'd want that thing in a cage in case of wheel or tire failure at high pressure. 

For rallycross reseating, I've seen a ratchet strap around the tire make it easier to re-seat, as it can push the beads mostly into place.  Helpful especially if you can't get air into the tire fast enough. 

Also, make sure you pull the valve core if things aren't seating easily.  Getting it up to pressure faster helps sometimes. 

+1 to everything here. The ratchet strap method has served me well for a fair few uncooperative wheel / tyre combinations, as has repeatedly inflating / deflating the tyre with the valve core removed.

Low profile tires can take a LOT to seat. Which makes sense, less sidewall equals less force from the same pressure, plus less sidewall equals less rubber to flex and stretch to ease the installation. They can be scary, and when they pop, they pop hard. I've never seen a catastrophe arise from it though.

gearheadmb said:

Low profile tires can take a LOT to seat. Which makes sense, less sidewall equals less force from the same pressure

And this is why in the rallycross world, more sidewalls means less pressure needed to avoid a de-bead (and having to go through this exercise).  

Whatever it takes to seat them. If I got over 80 psi I would throw it back in the balancer an tighten it down to hopefully prevent the wheel from becoming a flying projectile if something let go. Nothing ever did. I'd say in average most tires seated around 50-60 in my experience.

I know when I had a local tire shop mount my R888s for my old track rat Miata, they ended up having to take the tires and put them out in the sun for a couple of hours to soften them up to help them seat.

moxnix said:

dmack 15" rally tires warn on their page that they can take over 140 psi to seat.

https://www.dmacktyresusa.com/_p/prd15/2636937811/dmg2-195-65-15%22

The 185/70-15" DMG2 is dimension-ally identical to the 195/65-15", only labelled differently to accommodate class rules.

LOL at least they're honest!

A trick I've heard of to aid seating is to pre-stretch the tires by jamming objects between the beads and letting the tire sit like that for a day.

I think there's a bit of discrepancy here with what people suggest are "fixes".

There's getting the beads to come up to the rim, which is a problem with stretched tires or tires that were stored on their sides so the beads are 1.2 inches apart.  That's where you do things with putting them in the sun, ratchet straps, etc.

Then there is getting the bead to SEAT, meaning to come up over the safety lip.  That is where thigns can get hairy.  High air pressure and lots of tire lube is all you can do for that.  Stick a penny on the sidewall and see how far it flies when the bead finally pops on.

In reply to Knurled :

I've also read 40psi on every single tire I've ever done.  If it doesn't seat with that it gets more lube and a few wacks from a dead blow.

My tire machine maxes out at 60psi, lube and whacks with a dead blow did nothing. Aired down, pop the bead off the wheel, re-lube, air back up. It still wouldn't pop. I did that 4 times before I aired it up straight off the compressor. 

I did a set of BFG G-Force the same evening and they were fully seated by 20 psi. 

Maybe it was just those tires. 

On most 6 inch Kart tires, 40-50 psi was all it needed but we use a tire band. Now New Yellow Vegas on the other hand took 120+!

Can confirm, 15" DMacks are scary.  I've had multiple tire shops tell me to berkeley off- my go to technique now is to have them mounted at one place, then take them to a heavy truck shop where me and one of the old guys run a 50ft air line into the back lot, attach it to the wheel, and hide behind a block wall until the bead pops (at a dead even 150psi every time) and the wheel/tire combo jumps 8ft in the air.  This is the price of not worrying about debeading, I guess.

Dead blow hammer has been my go to tool for getting stubborn tires to seat. Never had to go beyond 60 psi that I can remember. 

Dead blow at 50, nothing.

Dead blow at 60, nothing.

Dead blow at 70, nothing.

Dead blow at 80, nothing.

At 90, it finally popped. Sounded like a gun shot. 

¯\_(ツ)_/¯ said:

Can confirm, 15" DMacks are scary.  I've had multiple tire shops tell me to berkeley off- my go to technique now is to have them mounted at one place, then take them to a heavy truck shop where me and one of the old guys run a 50ft air line into the back lot, attach it to the wheel, and hide behind a block wall until the bead pops (at a dead even 150psi every time) and the wheel/tire combo jumps 8ft in the air.  This is the price of not worrying about debeading, I guess.

You still have to worry about debeading with Dmacks...  Granted you might get a little more before you do it, but it's gonna happen.  Unless you drive like a weenie or something :)