ABS Brakes and tire sizes

I have a 1997 GMC sierra stepside that I am building as a sports truck.
I bought SS454 wheels for it, they are two rim widths so I have two sizes of tires, front and rear.
275/60/r15 rear 28" diameter
235/75/r15 front 28.9 diameter
721 and 699 is the rotation difference about 3.2%
It occurred to me while i was bleeding the brakes that I might have created a problem with the two sizes and the ABS unit
Will the size difference during braking trigger the anti skid while stopping?
It has the Kesley-Hayes with sensors on the front rotors with a third sensor
in the manual transmission for the rear drums speed sensor.
It is not running or even road ready to actually verify anything yet, just thinking about it and trying to decide if I need to address it with new tires or something else besides removing the system and wasting the money I spent on the stainless steel brake lines.
I tried to google it but all I came up with that search is that some ABS units will allow a 5% difference between the front and back, mostly on car forums.
I appreciate any input or thoughts as i continue putting the truck back together

I would refer to the service manual and kelsey hayes unit repair manual for any references to non matching front and rear wheel installation or prohibited type installs. Or tweak the profile/ width for matching diameters front and rear.

5% is the usual quoted figure for variation in diameters. What you need to watch for is only having 1.8% left as a margin. That can be used up with say, more worn tyres on the rear than front. In your favour is that the larger diameter tyre is also the higher profile one and at the front. Thus, it should have more flex and can be run at lower pressure - both will reduce its rolling radius (measured from centre to ground allowing for sidewall deflection).

On the smart that I had this stuff was prevalent but when say, new tyres were fitted to one axle but not the other and the ESP would start kicking off, disconnecting the battery to re-boot the ECU worked as when re-booted it immediately learned the new sizes. If this applies to your truck also, then you shouldn't have too much to worry about.

Thanks again for the information I really appreciate it

An easy solution is to swap the 235 75 for 235 70. That will bring the rolling diameters nearly equal.
No need to reprogram a thing