That is what I call bulges on the side of a tire. Have Rainer tire's on my new 2016 Jayco North Point 341RLTS. The RV is going on a seasonal site this year and next year. Will replace before I start towing it next fall.
2019 GMC Sierra Denali 3500HD CC 4x4 Duramax
2016 Jayco North Point 341RLTS
They've been great for me so far. I replaced mine after about 10 months of use with the Rainers due to a bald spot that showed it's ugly face. I went off of Magnolia Tom's recommendation and haven't looked back. I've had them on since November of '16 and they've been great thus far.
'16 Ram 3500 MC CTD Dually, 4:10 rear
'14 Ram 2500 MC CTD (gone)
'14 287BHBE (gone)
'16 North Point 377RLBH (current and hopefully last)