That's surely a wrong default Windows parameter in your PC for this particular file type.
Have a look in the "Choose default application by file type ".
I suspect that PDF reader is the actual one for .zip files and that's why it might appear as PDF file.
Looks like Win10 from the screenshot, which means .zip files can be opened in Windows Explorer by deafult, but like @Jempy said get yourself 7zip to open the archive files from RaceDepartment
Right click on the file and choose "open with". The top off the list would be your PDF program. Wrong as you know. Windows will give you 1 choice so click on "more apps ". Choose windows Explorer. Should open with this. Or download the free zip app from the Mocrosolf store. Once installed choose that to open the rar/wip files.
BreeZip is free but it only opens the files or extracts them. It wont pack zip files. But it's free.