Jim’s Tech Talk
By Jim Langley
Rating: 
Hot
- Effortless to use – no more upper body workout
- Smaller than some CO2 inflators
- A whole new type of mini pump – a tiny air compressor!
- Battery-operated – no need to buy CO2 cartridges
- Charges in 20 minutes with USB cable
- Presta/Schrader compatible
- Only 115 grams
- So small it might even fit inside a frame compartment
- Durable aluminum construction
- Silicone cover to protect you and your rims
Not
- Loud enough to be annoying
- Takes more time to reach pressure than you might expect
- Need to keep it charged
- More expensive than most standard mini pumps
- No pressure indicator/gauge
Price: SRP is $89.99
Weight: 115 grams
How obtained: Sample from the company
Availability: From the company and on Amazon
Website: https://www.cycplus.com/products/tiny-pump-cube
RBR sponsor: No
Reinventing the Mini Pump
If you use Facebook to follow cycling friends and to keep up on bicycling news and trends there’s a good chance you’re seeing ads for a new category of mini pumps that are electric (battery powered). They look like little black boxes, so small they could easily fit in the palm of the hand.
They have a hole in one end or a nozzle that fits onto a tire valve. And simply by placing them on the valve and turning them on, they will inflate your tire.
A CO2 inflator will do that too. But a CO2 inflator uses cartridges full of compressed CO2 that you have to buy. These new “box” inflators make their own air, so it’s free, just like it is with standard mini-pumps, the push and pull kind.
I’ve been seeing these ads since they first appeared and considered buying one of these new pumps but I couldn’t tell if they worked well enough to be depended on to fix flats or soft tires on rides.
Cycplus
Then, a couple of months ago, the company Cycplus contacted me and asked if I’d be interested in testing and reviewing their Cube bike pump, which I had not seen on Facebook but that was one of these tiny electric “box” pumps. I asked a few questions about the suitability of the pump for on the road and trail flat repairs and they assured me it was a quality product made exactly for that purpose. So I decided to give it a try.
A tiny air compressor
The Cube comes in a rubber cover to prevent any possibility of scratching your bike or rims when using it. It also protects your hands from the body of the pump that heats up as it inflates. It never felt super hot to me. But it might to you and if so you’ll be glad to have the cover.
The covers simply pulls off and underneath you can see that the Cube is made of aluminum. I thought it might be made of plastic. There are 3 screws holding the pump together so it was easy to take it apart to see how it works.
I thought there might be a spinning device inside forcing the air out like a turbocharger in a car. But the Cube actually has a miniature pump inside with a plunger driven by a brushless motor powered by two batteries.
The air intake is the same port used for charging the batteries. When the pump’s running you can put your hand over the nozzle and feel it blowing out air in rapid individual blasts in time with the plunger’s action. I was pleasantly surprised by how much air it makes and how fast it comes out too.
Construction
The Cube is built of quality materials with an aluminum body and mostly metal construction inside, too. It also comes with two batteries instead of one. I know that in some RVs 2 6-Volt batteries are used instead of a single 12-Volt battery because that setup works better.
Maybe the Cube’s twin cells work the same way and they might create less heat than a single battery. I’m not sure about either of those things but I don’t think they would have used two if there wasn’t a reason. I’m guessing the batteries are lithium ions but Cycplus didn’t say what they are.
Any pump is only as good as its air delivery device and the Cube’s pump head holds onto valves securely and was air tight on all the tires I inflated – multiple times, too. I did NOT try it on any Schrader valve wheels. It does come with the parts to convert it to fit Schrader valves.
Battery powered
I’ve shown the pump to several riding friends to get their take. A common complaint was having one more thing along that needs to be charged. If you forget that it’s in your seatbag or frame long enough, maybe it won’t still be holding a charge when you need it to fix a flat?
But I countered that you may already have a Garmin or cellphone you rely on on rides that has to be charged – or electric shifters for that matter. And also, if you rely on CO2 inflators (which inflate much faster than this tiny air compressor), a common mistake is to forget that you used your last cartridge fixing your last flat – kind of the same thing as forgetting to charge something.
My buds asked if the battery runs long enough to let you fix multiple flats if you had really rotten luck on a ride. Cycplus says that the pump has a “sustainable inflating time of about 200 seconds.” Also that it will inflate 2 road tires to 80 psi.
In my tests the Cube was able to do that but it took a minute longer. So, unless you carried a portable battery to recharge the Cube (and didn’t mind waiting), you wouldn’t be able to handle multiple flats.
Charging and run times
Some of Cycplus’ documentation says that the Cube can be fully charged via the USB cable in 20 minutes and in other paperwork it says 25 minutes. I was able to charge it fully within those times.
Here’s a chart showing their estimated run times to inflate tires to different pressures when the Cube is fully charged. My inflation tests took longer than their estimates but they do have the disclaimer on the chart that it’s “experimental data,” which makes sense with how tire widths vary so much from what’s printed on tire size labels.
Specifications
Verdict
Overall I’m quite impressed with the Cube. It’s not perfect. It takes a while to inflate tires and if you’re in a hurry you might get frustrated.
But it’s so easy to use! Just push it on the valve, turn it on and let it pump up the tire. There’s no need to do any pumping. And there’s no risk of breaking the Presta valve from pushing and pulling. These things alone could make up for having to wait a bit.
The other objection is how loud it is. If you ride in neighborhoods and flat at 6 a.m. you might worry about waking everyone up.
Still, it’s an entirely new design for a take along bike pump. It’s small enough to fit in any bag or pocket and light enough to hardly know it’s along for the ride too. And so far for me it has worked very well on road, gravel and mountain bike tires, so it’s very versatile.
I wish it had a built-in pressure gauge. Because it inflates tires so slowly that you could think more time has passed, or assume you have enough pressure and then find out the tire’s too soft to ride on. But, it’s easy to just put the pump back on and let it add more air.
Regarding those other similar pumps in the Facebook ads, I asked Cycplus if they shared their design with others and they said they only make the Cube. So I don’t know for sure if the other pumps work the same way the Cube does. If you have one and know, please let us know in a comment.
Watch my video review
The best way to learn more about the Cube is to see it in action so I did a pretty extensive video review too. In it you’ll hear how loud it is, see inside the pump and watch me inflate a gravel, road and mountain bike tire with the Cube. Enjoy the show!
Jim Langley is RBR’s Technical Editor. A pro mechanic & cycling writer for more than 40 years, he’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Tune in to Jim’s popular YouTube channel for wheel building & bike repair how-to’s. Jim’s also known for his cycling streak that ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.
Undoubtedly has two batteries in series to get a higher voltage to more efficiently run the pump motor.
no mention as to whether you can use it to seat tubeless tires. I don’t have an air compressor and am looking for options when replacing tubeless tires.
I’ll wait for Jim to respond, but it seems very unlikely that a tiny pump that takes several minutes to inflate a tire would ever generate enough air volume to seat a tire. I can’t even reliably seat a tubeless tire with my full sized Trek floor pump that has a high volume setting, although it does work sometimes. I often end up using a large air compressor made for cars and trucks.
I think this is designed to be more of an electric equivalent of a mini pump.
We did write an article about floor pumps that are specifically designed to be able to seat a tubeless tire here:
https://www.roadbikerider.com/these-floor-pumps-let-you-mount-tubeless-tires/
I use the Specialized Air Tool Blast and it works well enough to seat both road and 29er mtn. bike tires.
Thanks for asking Tom. There’s confusion over two tubeless terms here. You said “seat” but what you’re actually talking about is “sealing” the tubeless tire because that’s what keeps the air in.
The Cube is just like a mini pump. It’s made to fix flats or add air to a soft tire on the road or trail.
With tubeless tire flats the best way to fix them is with a plug. Do that and you’ll just fill it with air. The Cube will work.
If you had to remove and patch a badly cut tubeless tire. You would want to install a spare tube most likely. No need to seal the tire since it’s not tubeless anymore. The Cube will work to inflate the tire.
If you have a tire that doesn’t want to seat after an on the road flat repair you can pull it out by hand maybe, let the air out and lube the beads, etc to try to get it seated. Often just riding on the tire will get it to seat.
Now “sealing” tubeless tires – a new tire the first time – a mini pump and the Cube don’t put out enough air or fast enough airbto seal tubeless tires. But there’s no reason anyone would use it that way. You’d do that at home with a compressor or floor pump made for the purpose. Occasionally you’ll find a tubeless tire that seals easily but not always.
Hope this explains,
Thanks,
Jim
I use the Specialized Air Tool Blast and it works well enough to seat both road and 29er mtn. bike tires.
I’m running 700x35s on both bikes. I know the ‘wider tire revolution’ has some roadies riding even wider, up to mid 50s. Extrapolating from your experimental times chart, it might take 5-6 minutes to fill the tire. Now we’re talking a distinct time disadvantage over a pump. BTW, I use a full-size frame pump, so it inflates pretty quickly. Maybe someday the battery version will be built into a pumpable pump to have the best of both worlds! And, since one of my bikes is tubeless, I like the idea of adding a ‘blast’ option!
Thanks Dave. You can see in my video that it inflated a 45mm tire to 25psi in 90 seconds – riding pressure. In my view it’s completely unnecessary to add a “blast” option to a portable pump – you should use a full pump or even compressor for sealing new tubeless tires at home (should never be needed when riding).
I’ll write more about this in Tech Talk next week.
Thanks!
Jim
Thanks for the review Jim. This may be good for my wife to use when she rides by herself, as CO2 cartridges and pumps seem to intimidate here. One thing I’m interested to know is if the pump gets so hot that it could melt the valve stem, especially if using TPU tubes (like Tubolito or RideNow), which have plastic valve stems. It would be great if you could check that out and get back to us in a future column.
It looks like Rockbros makes a similar pump (which might be the same as the Australian made Fumpa Nano). I’m curious to know if there are clear advantages among the several brands.
Thanks for asking DJB. The Cube doesn’t get that hot at all. It might “hurt” really delicate hands but it would never heat up a valve significantly because it’s blowing air into the valve. Also, it’s the body of the pump that heats up not the head that delivers the air. So no worries at all.
I have no idea how the other seemingly similar pumps work. I did ask Cycplus if it was their design and they said no. But I would think all these pumps work the same way. If you visit the Cycplus website you’ll see they make slightly larger pumps that probably use a larger mechanism to inflate faster and oversize tires like car and truck tires. So they sure appear to be an established company.
I’ve only tested the Cube and it’s been working great. Yesterday my friend Tony flatted his rear tubeless tire about 3 miles from home. We stopped 3 times and I pumped it up each time with the Cube and we continued on and got home on a soft tire that the Cube kept inflated. It was MUCH easier than stopping, putting a pump on the valve and having to pump. I think your wife will love having the Cube along on rides. If there’s any concern that she doesn’t keep it charged, just have her carry a mini pump as a backup.
Thanks,
Jim
Similar devices are now being built right into the wheel for on the fly tire inflation and deflation. I believe they made their first appearance in this year’s Paris Roubaix to handle the road (inflate) and cobbles (deflate).
Thanks for the reminder Charles. Here’s an article on Jumbo-Visma’s Atmoz tire pressure system they used this year at Paris-Roubaix: https://www.bikeradar.com/news/paris-roubaix-tyre-pressure-control-systems/
Thanks again,
Jim