Which size tire would seal the bead best?

So I have a hard time sealing the beads on my tires so I think I'll need to get different set of tires for my rear wheels. The odd thing is the tires seal when off the car. I have 235/35/19 on 10.5" wheel and non of them seal for some reasons one wheel is very bad but I found out the other wheel also don't seal. They only leak when the weight of the car is on. So i was thinking if i should get 235/40/19 or 245/35/19 but not sure which would seal better. I don't have much room anymore for wider tire, but I'll add more camber to fit wider tires if i have too. Also which brand tire do you guys recommend for better tire bead sealing? 
Here is how much room i have for wider tire.
[IMG]http://i108.photobucket.com/albums/n13/mehrshad/IMAG0637.jpg[/IMG]

That really shouldn't leak.  Between those, I'd try to the 235/40 for the bigger sidewall but really those tires will stretch about the same. 

Before you do that, double check where it's leaking. It could be a lot of things.  In my experience it's usually valve stems or the tire beads got damaged during mounting.  When that happens, the added weight from the car will usually make it leak or leak faster.  Make sure to clean the bead seat really well and use bead sealer.

I did put bead sealer on. they do leak from the beads. The tires held air for weeks, but as soon as I put them on they start leaking. one is very bad that at first I thought it's rubbing from the noise it was making while driving lol. i think i'm going to put a set of new tires on. which brand runs wider than the others for the same size tires?

might be the wheel and not the tire. take a look at this when the tires are dismounted

That's what I though. The ex owner said his never leaked with same size tires. I'm guessing it's the tire. they were used anyway, so I'm going to get a new set to see how it goes.

[QUOTE=bashigs300;451125]That's what I though. The ex owner said his never leaked with same size tires. I'm guessing it's the tire. they were used anyway, so I'm going to get a new set to see how it goes.[/QUOTE]

Check if the lips are slightly bent or even the slightest crack, they can leak just from decimals away from rotational spec. Never take the ex owner's word for anything, we don't know what they went through. If they sealed with no weight and all a sudden some weight added the damaged area of the lip is stressed and air leaks.

I rock nankangs, achillies and dunlops with no problems. The old owner replaced the lips on those wheels so check the inner barrels. Also check the tire. If your tire tech tore the bead even just alil, that can cause a leak. I do tires as a hobby so double check that.

i ran a 225/40 on a 17x10.5 and sat on the bead fine with a big enough cheeatah
and it was on a used, superrrr hard, and almost 3 years old---ran it for a few months ^_^ to drift

i've got 225/35s on 10s up front with no bead sealer and no leaks....its the tire more likely if the rim looks clean

[QUOTE=lowlyfey34;451650]i've got 225/35s on 10s up front with no bead sealer and no leaks....its the tire more likely if the rim looks clean[/QUOTE]
 
cosign.

I'm running 215/35 on a 10" up front, and a 245/35 on a 12" in the rear, and neither leak.  

Sounds like it could be multiple issues though, you'll just have to start checking and eliminating one by one.

I had the same problem on my tires before. Its not holding air if its mounted in the car. I did all the checking too valve stems, wheel seal, bends(if any). Then i finally found out its the tire beads that are bad. Since i got the tires from my friend who always install and uninstall his wheels and his stretching it too so i guess the bead on the tire just gave up. Weird thing u cant really tell where is it coming from nothing visual the you can pin point that its the messed up part when i remove the tires. 

Not saying you have the same problem on yours but it could be. So my suggestion is to change the one tire that is leaking and go from there. Coz i guess theres no need for bigger tire sizes ive seen crazier setup than what u have. Goodluck.