2020 has 4", and they're junk imo. Less than 450 miles and they're toast imo.How about length 6”? Seems like the 2021 Riots have longer carbides?
The carbide itself really only helps on ice so I always use the longest I can find. I use the shaper bars (9") on a ZR6000 129 and I really like the precision they provide.i ran 6" shapers on my ZR8000 i liked them but sometimes in harder packed trails a bit more effort was needed to turn them. all preference really.