8" PVC (factory elbows to size correctly)

We have found recently that 8" PVC is available and being used on some of our projects. We are able to make the 8" size but the elbow doesn't adjust to size and bend radius like the pre-existing conduit sizes. Here is a link to the product site that should help with specifics on the products.

https://www.cantexinc.com/products/pipe-conduit/gad_source/1?gclid=eaiaiqobchmi_oenzorjhgmv2wbhar1-owoeeaayasaaegizzvd_bwe