As we mentioned, there’s little to no difference between the UB21 and UB22. In fact, both are priced the same on Adidas’ website. Although, the immediate but still bare minimum difference that we can point out is the reduced holes on the upper.
The UB22 has fewer holes on the upper than the UB21, which makes the UB22 a bit warmer in comparison. The holes on the UB21 run from the top to around the sides and well under the float TPU mid cage. Meanwhile, the holes that offer extra breathability to the shoes are only on the front of the UB22.
The stretchy material of the upper feels the same on both shoes. It has a sock-like fit on the upper whereas the heel area is dominated by the TPU heel counter. Aside from that, the Boost cushioning around the heel is pretty much the same as well. It still looks like you’re wearing three-inch Boost stilettos.
That wide heel area adds plenty of stability to the UB22, but it also makes them bulky. It’s lightweight but compared to the others in the market, the UB22 can feel heavy. Especially for very serious runners and athletes. The UB22 is also slightly lighter than the UB21 but barely, which is to say, it’s not light enough to notice without a weighing scale.