Hello -- First Time Poster -- Having a Problem with Back Wheels breaking Spokes - Heres Some Info

Trek 7500 - 700C Wheels - 24 Speed -- ( 135mm width hub ? ) - Weight 230 Lbs - I carry a 6 Lb tool pack and water on back rack - No Curbs / Jumps etc -- I Ride 20 - 50 Miles - paved road for Exercise, 2 or more times a week - Some Hills. Occasional Small Rocks / Fir Cones / Pieces of Bark from Log Trucks etc. But no Off Road - Slow on Railroad Crossings etc.

Bought the bike used and the First Back Wheel (700C - 32) began breaking spokes at the Hub and developed cracks between the spokes. Couldnt be sure of its past.

Bought a Set of Bontrager Camino - 32 Spoke wheels with 700C - 28 - 80psi ( they are double wall construction with eyelets ) -- 500 Miles began Breaking spokes again at the Hub. I had the Wheel Fixed by a Shop -- 150 Miles later broke another. I've been Chasing Loose Spokes after every Ride now. Getting pretty good at Re-tensionsing evenly using the brake pad as a statutory point to keep the wheel in line.

Not Sure to Just Keep Repairing and tweeking ... or ... Thinking I should maybe try to move to a 36 Spoke wheel.

No problems on either set of wheels with the Front Wheels. Probably not surprising. Thinking about just replacing the back wheel only. I Cant afford top of the Line but can spend moderate to get a set up that works.

I really like to get dropped off 40 - 50 Miles out and Ride Home -- the anxiety over my wheel is really taking some of the enjoyment out of the trip.

Any input appreciated - happy to provide any details i have overlooked to give the whole story. Thanks -