The objective of this post is to compare 19mm and 22 BMX spindles.
Definitions:
Bottom bracket – A system of bearings and a spindle/axle installed in the middle of the bike frame (bottom bracket shell). The bottom bracket allows smooth rotation of the cranks.
Spindle – An axle to which the crank arms of a bicycle attach. The spindle rotates inside the bike’s bottom bracket.
The Benefits of 19mm Spindles
The pros of 19mm BMX spindles are:
1. Availability
19mm spindles are the most popular size and consequently allow the user to choose between more crank arms.
It’s also a lot easier to find replacement parts for the bottom bracket.
For many riders, the above is a strong incentive to go with 19mm spindles.
2. Stronger, Smoother Bottom Bracket
The thinner the spindle, the larger the bearings of the bottom bracket can be.
As a result, 19mm bottom brackets have bigger bearings than models designed for 22mm spindles.
The bigger bearings make the bottom bracket tougher and smoothen the rotation of the cranks.
The Advantages of 22mm Spindles
1. Lighter
Most of a pipe/tube’s strength comes from its outer layers.
For that reason, a pipe is stronger than a solid rod of equal mass when both are made of the same material.
Bicycle engineers have been relying on this phenomenon to produce components with excellent strength to weight ratio.
The most obvious example would be bike frames – they’re all composed of tubes.
The larger the tube, the hollower it can be while preserving most of its strength.
22mm BMX spindles have 3mm larger diameters than 19mm spindles and can be hollower without losing strength.
To match the strength of a 22mm spindle, a 19mm one needs to be thicker or forged out of a stronger material.
Hence why 22mm spindles are often ever so slightly lighter.
2. Stronger (potentially)
22mm axles can be made exceptionally strong thanks to the extra material.
However, it would be wrong to conclude that 22mm spindles are always stronger than 19mm versions because the final strength level depends on the engineering and the production material.
3. Stiffer
22mm cranks are considered stiffer due to their larger diameter (a thin tube is easier to flex than a thicker one).
That said, many argue that the difference in stiffness between 19mm and 22mm axles is the effect of placebo rather than reality.
Truth be told, only experienced riders could tell the difference between 19mm and 22mm cranks.
If an average rider is given a bike with a 19mm spindle but told that it’s 22mm, the rider may say that the axle is stiffer because “it has to be”.
It’s also worth noting that the crank arms flex a lot more than the spindle itself. As a result, a cyclist may conclude that their 19mm spindle is flexing due to crank flex even though the axle itself is solid.
4. Pro Status
22mm and 24mm BMX cranks are the strongest out there and therefore present on the bikes of elite riders performing huge drops.
Most people will never be on that level, but many BMX enthusiasts take pride in riding indestructible components engineered for professionals.
For that reason, one can sometimes face a bit of illogical elitism coming from “22mm spindle snobs”.
Table Summary
The table below summarizes the pros and cons of 19mm and 22m spindles.
19mm Spindles
| Pros | Cons |
| Widely available | Cannot be as strong as the toughest 22mm spindles |
| Support bottom brackets with larger bearings | More flex (debatable) |
| Easy to find bottom bracket spare parts | |
| A larger selection of crank arms | |
| Cheaper (potentially) |
22mm Spindles
| Pros | Cons |
| Strong | Lower availability |
| Lighter | Smaller bottom bracket bearings |
| Stiffer | Smaller selection of crank arms |
| “Pro status” | More expensive (potentially) |
Making a Choice
The three main factors to consider when choosing a spindle or other BMX parts are:
1. Compatibility
If you already have crank arms, the spindle will have to match them. (If you have 22mm cranks, you need a 22mm spindle…etc.)
2. Intended Use
If the spindle will be used for amateur riding, both sizes will do just fine as long as the craftsmanship is good.
If the spindle has to go on a top-tier pro bike, 22mm models instantly become a more attractive option thanks to their higher strength.
3. Quality
It doesn’t matter how strong a spindle is in theory when the quality of the production is low.
A 19mm spindle manufactured by a reputable company will be a lot stronger than a cheap 22mm model made of low-grade materials.
4. Price
The price matters too. In most cases, it’s best to go for products in the medium price range – not too expensive but not cheap either. This range offers the most for your dollar.
Don’t Obsess Over Components and Just Ride
Just like computer nerds, many riders spend an unreal amount of time obsessing over their bike components.
Quite often the discussions are injected with a healthy dose of “paralysis by analysis” a.k.a. too much thinking and not enough doing.
If your bike is “healthy” and strong enough for your skill level, it’s best to skip the overthinking part and just ride regardless of the spindle size.
