Bike Trunk Bag 17L-45L Expandable Waterproof Rear Rack Bags

After lots of research and asking others opinions, we purchased the RockBros Trunk Bag 17L-45L rear bike bag. We put then on our XP4 Lectric brand bikes and the fit perfectly. We wanted a bag that would expand but not have the constant side saddle bags. I was concerned since other reviews said the water bottle holder was tight. We fit a large 24 oz bottle, 18 oz and a plastic 16 oz bottle in the holder. Pictures provided. I was pleased. The bag is roomy with different options to configure to store items. The large shoulder strap feeling sturdy for portability of the bag. The bag come with a brightly colored rain cover for easy visibility in the rain.

This is a well constructed trunk bag, with ample storage. I like such features as the hidden pannier bags and included shoulder strap, so you can easily take it with you. However, it was nearly impossible for me to secure the bag to my MIK-compatible rack using the bag’s Velcro straps. My e-bike has a fender, leaving little space between the fender and the rack. You have to snake the Velcro strap under the rack, through the buckle on the bottom of the bike bag, and then back underneath again to secure it. My bike probably offered an inch of space between the fender and the rack, making it very difficult to tighten the Velcro enough to secure the bag. I bought an MIK base plate and just attached it today. If you’re buying this bag and think you’ll want to detach the bag from your bike regularly, get the adapter plate. However, those Velcro straps are now in the way. If I fasten them over the base plate, I can’t snap the plate onto my rack. I hate to cut them off, because as soon as I do, I’ll realize they might come in handy for something else. I haven’t spent much time using the bag yet, but I’m not impressed with the Velcro attachment system. But, now that my Rockbros trunk bag is securely attached to my bike, I look forward to putting several miles on it.

I wish it was made out of leather but I've got really nothing to complain about. it's well made. the panniers are easy to get open and it stays in place so no worrying about an odd strap etc. ending up in the spokes. The only thing wrong with it is that it encourages you to carry around a lot of junk. The storage capacity is great. the zipper quality is okay. not the best but certainly not the worst.

Overall I like the bag and the flexibility it brings. The hard sides keep everything in place until you need to drop down the paniers. The saddle bags are fairly roomy and there is an elastic cord to wrap around a screw or rack frame to keep them from flapping as you ride. The 'trunk' is roomy and expands on the top. Careful! The first time i dismounted with the trunk extended (i forgot that it was higher up) I didn't quite clear the top of the trunk with my leg and I went down along with my ebike. Ouch. AFA the total volume of the extended trunk lid and the paniers, I'm pretty certain it ain't 45 liters. I haven't measured but it just looks appreciably smaller. YMMV One more thing. The zippers on the always exposed part of the bag are high quality, but the zippers for the paniers look like thy may only last a year. Plus they are not gonna help keep water out. At least there's a nice colorful rain coat for the whole setup.

Great bag, solid constructions, saddle bags pop out and are protected. Fit 3 bags of groceries into this thing.

I love this bag. I put a MIK adapter on it and it fits great on my MIK carrier. I love that it has built in panniers so I can carry more stuff if needed. The center part itself carries a lot of stuff and that's what I use most of the time but I have used the panniers a couple of times for longer rides. The panniers are fairly small so if you're going on a really long trip I'd recommend getting dedicated pannier bags instead but if you just want the versatility this bag offers I say don't hesitate. It's very well built and sturdy and also attractive. I also like having the extra water bottle holder on the back of it.

i commute on bike. this bag strikes a good balance between having a main pocket big enough to hold my usual gear, and being small enough to throw over my shoulder and bring inside with me. the saddlebags are perfectly good for bringing home takeout or whatever i forgot to get during my last big grocery run. i like how the rain cover is high-visibility yellow, great safety detail and i throw it on for nighttime visibility too. bag feels like its solid enough to take a fall (although ideally i won't find out!). overall pleased. EDIT: its 2025 now. i bought this and wrote the above in 2023. its still holding up just fine. no issues with stitching or zippers, and it stays on securely. the yellow rain cover is a little faded from sun, because i use it for visibility no matter the weather, but its still pretty bright and the reflective strips still work. id still recommend this bag! (and yes, it can take a little fall and be ok.)

This is a very well made bag. The stitches are solid and anchor points are double stitched. The zippers are not wimpy yet they are tight enough to keep most dust out. I havent used the rain jacket yet but it fits fine and will repel enough for any unexpected shower. The company was great to work with and really stand behind their product long after the sale. This is my second rear bag that I have purchased from them. This second purchase I selected one size larger it was maybe more than I need. That choice is on me and I got everything I asked for.

Great quality. Hard side keep loads where it should stay. Zippers are good quality. Like size of compartments and how they pack away. Nice rain cover. Only thing missing is some small pockets for keeping items sorted. Nice rain covers.

Very nice bag. Using on an e-bike. Lots of storage. Best price I could find for Rockbros bag.

Bonne qualité et polyvalent. Un peu lourd mais parfait pour un vélo électrique.

Great looking and very well made. Love the product!

Awesome bag for the price seems well made