If it were me, I'd want to replace both of those drives with a pair of Tandon TM-100-2 Double Sided Drives. Texas Peripheral Drives are cost-reduced (cheapo) clones of the Tandon drives. Tandon Drives are like tanks.
Just about every third party DOS on the Model I/III/4 support 80 track double sided operation. I did it with MultiDOS, NewDOS/80, DosPlus, LDOS, and others.
There are even patches for TRS-DOS to get it to work on non-standard drives.
I used NewDOS/80 most of the time, and then MultiDOS (which was released as Freeware, get it from Ira's TRS-80 site).
Sorry to necro-bump a thread, but I have a Model 4 that for some reason has TM-100-4 drives in it (double-sided, 80 tracks). It threw me for a while trying to "repair" it because it would not boot any disks from my other Model 4. Finally, I realized the drive model number and looked it up.
I was able to create some 80-track disks with NewDOS/80 that boot now, but it would be nice to be able to use it with "normal" disks. Where can I find the patches for TRS-DOS to work with 80-tracks?