Now for one more update after a summer of use, 9/2/18. I have used this pack every other day all summer long to take long bike rides with a stop at one or even two off leash dog parks to let my dog run free and socialize. I have found that I can also include stops at the store to pick up a couple items to carry back home in the side saddle bags. I leave my dog in the pack to go inside the grocery store, as well as ordering at cafes to take outside and then take the food to eat on the cafe patio or to go to a nearby park to eat. No one has objected to my dog in the pack on my back. Quite the opposite. Dog lovers seem to go bananas over her in the pack. I get lots of positive remarks from other shoppers and passing vehicles on the road as well. My dog stays really calm and very quiet while in the pack. Kind of like a security thing for her. It calms her. So no issues in any way with riding. The pack has withstood the heavy use. I do get very sweaty on my back where the pack rests. I wish for improvements here for better ventilation. The straps do flap and flick about in the wind while riding, so I tuck them into the straps to prevent getting hit in the face of me and my dog. When it was crazy hot out. I would stop at public fountains and get her wet or unzip and pour water over her to wet her down to help cool off. My favorite fountain has no pool and thus allows bikes to ride through the center to get good and wet. If I take her to a river beach, I end up with a very gritty and muddy shoulders and neck where her paws rest. The pack is easy to clean off with a hose rinse. And air drys quickly.My dog does look pretty damn cute riding in the pack.Ok, I am updating this review. I've been used the pack for my pup for 3 weeks. I do wish the straps were padded a bit thicker and that there was a hip belt for weight support onto the hips. But. That said, my dog loves to ride in the pack as I ride my bike to the off leash dog park and around town for erands (as long as she gets to get out of the backpack and run, sniff and play at the off leash dog park for some exercise)We get lots of positive comments too. I also need to add that my bike is set up for sitting upright while riding. And this dog carrier pack works just fine in this position. My pup is only 10 lbs. she likes to hang her head over to one side or the other to watch the world go by but this doesn't affect my balance on the bike in the least. I can't imagine using this pack with a dog while leaning over in a more prone position though. So far, my pup seems to tolerate about a one hour ride on the bike. After that she gets a bit antsy and asks to stop and get on the ground. Also, if your dog gets her feet wet and muddy, consider that you will too where their paws rest on your back. :)Also, I use the extra add on accessory pack to store my heavy duty U bike lock and cable and bungie corded onto onto the back wheel saddle bag rack. A very lightweight rain coat can fit into the accessory pack along with a wallet and keys... I have also taken to bringing my bike into the off leash parks and walking the bike along with my dog and using the kick stand to park the bike when we just hang out with other dogs and their humans. Easier than attempting to lock a bike to a wire fence, which is not at all secure.My first rides with this pack and my dog was to give the pack Three stars because the engineering and construction of this pack could improve a lot. I will say that they did improve on the thickness and padding of the shoulder straps since past reviews I read about how thin the shoulder straps were. Zippers seem sturdy. All the stitching is finished and no loose ends. The pack material seems sturdy and should last. Not as breathable as they claim though. The back of the pack is padded and has some room for venting and breathability. This could improve! My mountain hardware day pack would be a great reference for designing a nice breathable pack resting agains a back. As well as improving the straps, adding a thick high end hip belt and placing the chest strap in the correct place! Geeze! that one thing! Getting choked was not good! and this strap is rendered useless if your dog and gear weigh more than 10 lbs!!!My 10 lb. miniature schnauzer was easy to load into the pack and she goes calm and quiet while riding on my back in this pack. She does fit the size small pack. But the bottom where my dog crouches in a sit position slides and angels onto my back flat instead of staying flat and horizontal to the ground for her back legs to fold into a sit/crouch. Maybe with the block they sell separately, the bottom of the pack would stay flat, but that would make my doh not fit the pack.I bought the pack for bike riding to the dog park. After testing out the dog park bike ride, I would never ever use this pack for carrying a dog over 10 lbs while hiking. The incorrect placement of the chest strap and lack of a good thick hip belt make this pack a hell pack and a hell hike with a heavier dog. Plus you would need a companion to come along and be willing to carry your share of lunch, snacks, water, etc.I also got the detachable accessory pouch. Thinking I would carry the - oh so- damn heavy kryptonite bike lock and cable, leash, dog treats and maybe a light rain jacket? It does fit the u-shaped lock, cable for the front tire, leash. and small dog treat/ball pouch and a small collapsable water bowl. There is a smaller outer pocked for a large smart phone, small wallet and keys. No room for a light rain jacket if it's threatening to rain.I would not choose to carry a dog heavier than 10 lb. My bike lock is super heavy duty and heavy and it added 4 more pounds to the entire pack. There is no way I am going to leave my bike unlocked and unattended at a store or a cafe or park. I live in a town where bike theft is very high.Attaching the accessory pack loaded to the back of the dog inside the pack is cumbersome and not good. If the pouch was just light stuff it would be ok. I had one full 16 oz water bottle in the side pouch. When I put the pack on with the dog and accessory bag packed with bike lock, cable, leash, and water bottles. It was 78 degrees and breezy out. I rode 10 miles total with a stop at the dog park in the middle of the ride.With the accessory pouch attached to the pack, and the chest strap snapped, the chest strap rode up at my neck, no matter how tight or loose I adjusted the shoulder straps, choking me. I had to turn around and ride back to the house, take off the pack and remove the pouch and bungie it to my bike's rear saddle bag rack. Without the extra 4 lb pouch, the chest strap would stay just at my collar bone. So in reference to my really high end day pack that carries about 15 lb max with emergency gear and water bladder, food for a long 20 mile day hike up in the mountains, with really nice and thick padded straps, the chest strap rides at mid chest no problem. That is not the case with this dog pack at all.I choose the light grey color to keep my dog and me cooler knowing that the black, blue or red colored pack would attract more solar heat.There is NO PLACE to store the leash except in the water bottle side pouch? I could bring along a saddle bag but then there is the issue of locking up the bike and no way to keep the saddle bag secure and having to schlep it along on on the walk inside the dog park. This dog pack was easy to leave hanging from one shoulder so the sweat and my shirt could dry out while my pup romped, socialized and played with the other dogs off leash.On the return ride, my pup was hot from playing and I did wet my dog with water before putting her back into the pack for the ride home.I am going to give it one more test try before I decide if its going back.