I'm wondering if anyone has an opinion on Verlindens or Custom Dioramics distressed road wheels for the M4? Do they look authentic or are they too much for an actual vehicle?

Welcome aboard Hellcat! Great name by the way! I love those TD's!
I was looking at them myself not too long ago. I really haven't seen too many Shermans that have wheels all torn up like that. All my reference material does not show any pics of them like the ones from Verlinden nor CD.
Maybe someone else has another opinion on them. I guess they would look okay for a war-torn vehicle. One thats been around the block a few times.

I seem to recall that 50% separation of the rubber "tire" from the wheel (you stick a pocket knife or screwdriver blade between rubber and metal for 50% of circumference of wheel), We usually replace the roadwheel when rubber chunks alway down to metal were missing. I had used an exacto knife to chunk road wheels and the center guides can punch big holes when the wheels "ride the center guides" during sharp turns in deep loose soil or mud. Missing rubber makes it easier for the road wheels to walk off teh track, resulting in a thrown track or a broken track depending on terrain and track wear. Back in teh late 70's when repair parts money was tight we had some pretty poor looking road wheels.

Most pictures of Shermans only show minor to no damage to road wheels. They spent a lot of time on roads.

Having habitually dinged up the rubber on running gear for a while, I decided to look at my references a few weeks ago!

I looked at German and Allied armor in action, and saw little evidence for visible wear on rubber wheels. Unless the vehicle had burned, there was little to distinguish new from old wheels. And, in many cases you can see the original seam on the rubber tires. So don't sand too much! But be prepared for judges to think you screwed up!

I will no longer ding up the wheels unless I see some convincing photographic evidence. I'm sure the wheels are worn, but it just ain't visible in 1/35 scale!! Kind of like all the rust patches that don't show up in photos!

Cheers
Andy

Just remember, the position of the road wheel usually determines the type of wear. The last road wheel gets rattled by the guide teeth as the tank turns. This constant vibration usually causes the rubber surface to look like a jigsaw puzzle or like cracked earth. The first road wheel (front one) takes the greatest beating from traveling across the terrain (comes in contact with the terrain hardest). They tend to get chunked the most and lose the hunks of rubber. The other road wheels get chunked badly too, just not as often.