BMX - Tire size for ACS Z-Rims 26"

Hello BMX folks,

I came over from Classic & Vintage looking for info, since I know little about BMX bikes and parts.

A customer brought in a 26" wheel Schwinn Cruiser, heavily customized with a BMX stem, BMX bars, MX front brake, etc. The bike also has a handbuilt set of 26" wheels with what look like ACS-Z Rims. The only markings that I can find say 'ACS-7' so assuming that is meant to say ACS-Z. There also remnants of logos on the sidewalls that look like the logos of ACS-Z rims I found on google.

Anyway, the guy has whitewall tires that look to be 26 x 2.125 cruiser tires, but both tires came completely off the rims after riding and being in storage. I wonder if maybe he had the wrong ISO size, cuz it's a mess. The guy wants to get the correct size tires for his wheels, and I need to help him.

Does anyone know what ISO size the ACS Z-Rims would have needed? I searched google and on this forum, but haven't found anything conclusive about the tire size.

Thanks for your help!

EDIT: I have also emailed ACS to see if they might remember.

most take mtb sized tires 590 I believe? My 26" araya's do in any case.

Thanks toytech!

Here's the emailed response I received from ACS, which might explain why the tires have blown off the rims:

The best answer I can give you is 26 x 1.75; sorry I don't know the ISO diameter.

The 26" Zrims were very short lived as they were too flexible. Don't know if the flex played a part in the blow off. Another thing to consider is that the Zrims are not hooked, so tire pressure should be kept at 40psi or less. If the tire was over inflated for a prolonged period, it is possible that the rim flanges were pushed out, causing the tire to blow off. If this is the case, take the tires off for several months. The flanges will eventually go back to their original position, but it is a slow process.

ACS

And this is why we roll on 20" alloy rims...

20's are for kids :P