Yes agree...
My Mom complained of the same thing on hers...she has more than one so we compared to the other And discovered the bristles are stiffer and more dense on the one that pulls forward more. Your local Aerus dealer is who services these now as the name has changed. They will come out to the house or you can go to the local branch. Website is aerusvacuums.com and there is a dealer locator tab in the top right corner. Replacing the brush roller will likely improve things, but it could also be a case of a different type of carpet...if this is new carpet it could be thicker causing this too as I elaborate on a bit more when we compared it on different, thicker carpet in the same house but in a different room.
The back wheels are spring loaded and push down and back simultaneously on the forward stroke but only on thick dense carpet and spring back up on the backstroke. So it is constantly adjusting the height every second to best contact with the carpet and to maintain an easier push. It resets itself on the backstroke. It is by far the best fully automatic self adjusting system I’ve ever seen on any vacuum cleaner bar none.
Denser carpet will definitely be a bit tougher to push. My Mom has very thick expensive dense carpeting in her master bedroom and there is a significant difference in the push that is needed in that room compared to the hall and neighboring bedrooms all of which have different carpet. Most of the other rooms the height Adjuster doesn’t engage but it does on that thick expensive master bedroom carpet. They bought that thick carpet in 1987 and it still looks like new.....it has still never matted even in the high traffic locations. A few years ago I told her I really liked the carpet in that room because it has stayed so nice after all this time, nicer than the hall with much newer carpet and she said that’s because it is super expensive carpet as she wanted it to be very nice for her room as they did a full redecorate of the room at that time, changing wallpaper photo, adding stained crown molding to match the furniture, etc.
Jon