Crankbrothers Gem Review
Our Analysis and Test Results
The Crankbrothers Gem is an excellent pump and a great value. It offers the unique and well-designed feature of allowing you to toggle between high pressure and high volume pumping modes while maintaining high quality all around.
Ease of Attachment/Detachment
The pump head on the Gem wasn't a favorite design of our testers. It has separate holes for Schrader and Presta valves on the same side of the pump head, which can make it challenging to get a quick seal on your valve. With Presta valves, this often involves a few air-leaking bumps before contact is made. However, there are some advantages too, including a very slim head that's easy to slide between your spokes, as well as no physical adaptation needed when switching between valve types (some pumps require disassembling and reassembling the head to accommodate a different valve).
Our testers found that the head on the Gem would sometimes spontaneously pop off if it was not securely seated and clamped, and this took significantly more effort than most other pumps we tested. That said, there wasn't much air leakage while connecting or disconnecting, and the locking lever is easy to engage (which may be why it pops off more easily and with less air loss).
The hose is a relatively generous 36 inches long; maybe not quite enough to easily reach a bike in a work stand, but still longer than several other models in this review.
We don't spend a lot of time discussing extra attachments with most floor pumps; the majority of these pumps come with a needle attachment (for sports balls) and a cone attachment (for pool toys). If a pump doesn't include them, you can pick them up for less than $5 online. However, the Gem earns a special mention as it does a great job providing storage space for these attachments in a hidden compartment inside of the handle. If you don't need them, they'll never be in your way; if you do, you'll always know where they are.
With a very nice wide steel tripod base, solid all-around construction, and a low center of gravity, the stability of this pump is excellent. Our testers had little trouble standing it on various uneven surfaces, and it strongly resisted any attempts to knock it over. Some pumps with large gauges that are up off the ground can be put off balance by this heavy protrusion; the Gem solves this problem by casing its gauge in lightweight plastic and designing it to wrap around the barrel. The gauge is a whopping 3.5" wide but extends only 2" out from the front of the barrel. The front leg of the tripod extends 4".
The Gem also feels quite stable while pumping, which is especially important when in high volume mode. Pumping a high volume of air per pump stroke can very quickly become a physically demanding task, requiring pushing down a lot of one's body weight onto the handle. The Gem hardly wobbles even in this HV setting and feels strong enough to take the necessary beating.
Inflation speed is a difficult factor to describe with this pump and its unique HV/HP switch, but ultimately, we found that a smart use of both the high volume and high-pressure settings can offer excellent results in this area.
When pumping purely in the high-pressure mode, this pump offers some of the worst inflation speed around. We needed 32 full pump strokes to get a hybrid tire from 20 to 80psi; most pumps in our tests required roughly 20-25 strokes to achieve the same result, and a few needed even less. If this were the only setting on the pump, it would be dead last in our speed ranking. On the other hand, operating in high volume mode, the Gem moved the needle the same distance with only 12 pump strokes — but we found depressing the handle to be very physically strenuous when pumping at higher pressures, which hurts the actual time involved quite a bit.
We ultimately found the best results were achieved when mixing the two methods, and flipping the HV/HP switch when pumping in high volume mode became too difficult. Flipping the switch is very simple while pumping, as the switch can be operated easily with your foot. Using this method, we were able to pump the same tire from 20 to 80psi using 16 gentle smooth pump strokes, a very impressive result. It does take a second to stop pumping and flip the switch, but it's not enough to significantly impact the time involved. Quality of pump strokes is also quite good since the pump is so stable. The handle is on the narrow side but is comfortable enough to hold.
Our tests found the Gem to have great accuracy, always within 1-2psi of our independent gauge. The needle moves pretty slowly when using the high-pressure setting, making it very easy to fine-tune your tire pressure when finishing off your pumping.
There can be some minor air loss when connecting or disconnecting this type of pump head, though we didn't have any significant problems, and the 1-2psi differences we detected tended to be over the intended pressure rather than under, so this didn't seem to be a major issue overall.
At 3.5" across, the gauge on the Gem is one of the largest around, and it is cleverly designed to wrap around the barrel of the pump, helping with stability. It features white numbering on a black background with a light gray needle. PSI numbers are labeled every 20psi, with hash marks every 5psi. These small hash marks can be challenging to make out while standing above the pump, however. It's all easy enough to read but may lack precision for measurements smaller than steps of 5psi.
The gauge is all cased in hard plastic, which feels only a little bit flimsy. Most of any perceived flimsiness is probably because the gauge isn't securely attached to the barrel — it tightens down with a screw and nut in a clamp-like design around the barrel. This allows the gauge to be (awkwardly) moved around to different sides of the pump, if you want to do that. It's perhaps an odd feature, but it's certainly not hurting anything, and, ultimately, the gauge is large, relatively clear, and accurate, so we're pretty happy with it.
We think the Crankbrothers Gem offers excellent value. It's well made, performed well across all our tests, and has the possibility of operating as two different pumps in one. It's a few dollars more than the entry-level bargain pumps, but you're getting a higher quality product that can meet all your pumping needs at once.
The Gem genuinely impressed our fleet of bike pump testers. The novel HV/HP pump mode switch offers a solution to a problem we didn't know we had and delivers it well. The wraparound gauge allows for an increase in size without compromising the pump's balance point, and the hidden storage for the extra pump attachments is very thoughtful. And we love the tripod base. All around, this "gem" of a bike pump is a great value for all of the features and the excellent overall design. This is an excellent pump for the quality-conscious-consumer-on-a-budget.
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