If my memory hasn't failed me completely I think it was discussed here in Armorama some time ago.
The ribs are way over scale.
This is what it "should" look like on a relatively fresh wheel:





Those ribs on the "sidewalls" would be more or less invisible in 1/35th-scale. The surface rubbing against the track gets worn smooth very soon.
The ribs on the sidewalls in the images above are probably the same as when that wheel was pulled out of the vulcanising moulds.

They could also look like this:

but that is a lot more work for the model builder
/ Robin


Edit: I found this:
http://www.themodellingnews.com/2016/06/construction-review-ptii-andy-builds.html
Some kind of build blog/review.

The Takom kits of the T-54B, Type 69, and other of their tanks I notice have big ribs on the rubber wheels. It's difficult to believe such ribs would be on the road surfaces, or if they were, to last long after the tank gets driven for any length of time. Or am I wrong? I'm thinking of how the old Tamiya T-55A kit did not have them.

....

.....
Takoms wheels are a little overstated but it is easier to remove than to add....

Quoted Text

---

....

.....
Takoms wheels are a little overstated but it is easier to remove than to add....

---

umhum, there are a few Tamiya T-55's lurking in the stash with various conversion sets.
I think I will fill the grooves with stretched sprue and then file down the surplus. Should be doable if approached as some kind of series manufacturing .... aarggghhhhh
There is also the wheel sets by Miniart .....
/ Robin