from Rookie’s keyboard
Hello, friends
Today, I am going to analyze the two types of BMX cranks – 2-piece and 3-piece.
Let’s start with the basic definitions:
Two-piece cranks (2PCs) are made of two distinct parts – a “free” crank arm plus a crank arm with a spindle attached to it.
Three-piece Cranks (3PCs) include 3 elements – 2 separate/free crank arms plus a spindle/axle.
The Pros of 2PCs are:
- Faster installation
Two-piece cranks are easier to install because one of the crank arms is already hydraulically pressed or welded to the spindle and does not require additional adjustment.
The pre-connected crank arm can be used as a handle when getting the spindle through the bottom bracket.
- Stiffer
In theory, two-piece cranks should be stiffer because the spindle is integrated into one of the crank arms and thus the power transfer during pedaling is stronger.
In practice, that mythical stiffness cannot be perceived by a mortal.
- Lighter
Two-piece cranks usually weigh less because the spindle has a larger diameter and can therefore match the strength of three-piece models with less material.
The absence of a pinch bolt on one of the arms saves some weight too.
But of course, not all 2PCs are lighter than their 3PCs versions.
The table below compares the weights of popular 2PCs and 3PCs BMX cranksets:
| 2 piece | Weight | 3 piece | Weight |
| BSD Substance Freestyle | 884 grams | Cult Crew 19mm | 860 grams |
| BSD Substance XL V2 | 861 grams | Mission Transit V2 | 1084 grams |
| Kink Pillar 2PC | 808 grams | Rant Bangin 8 | 978 grams |
| Odyssey Thunderbolt | 788 grams | Odyssey Calibur V2 | 945 grams |
| Bossless Indent 24 | 710 grams | Eclat Onyx | 898 grams |
| Premium | 805 grams | Stolen Mob V4 | 991 grams |
| Eclat Tibia | 934 grams | Colony Venator | 731 grams |
| Stranger Mass V2 | 840 grams | Kink Brace | 948 grams |
| GT Power Series | 803 grams | Shadow Killer | 934 grams |
| Fiend Team V2 | 947 grams | Stolen Talon V2 | 986 grams |
| Average: | 838 | Average: | 935.5 |
Conclusion: The 2PCs in the table are 97 grams lighter. But some 3PCs models are very light too.
Heavier cranks aren’t much of a detriment due to the position of the weight – in the middle of the bike.
If the extra weight was near the front or back, it would have a greater significance.
The Downsides of 2PCs
- You Can’t Remove Both Crank Arms
The structure of 2PC cranks makes it impossible to remove both crank arms since one of them is machine-pressed into the spindle.
If that crank breaks or cracks, you will have to buy a new set if you can’t find a spare on the second-hand market.
- More Expensive
2PC cranks tend to be more expensive than 3PC.
- Fewer Options
3PCs have been the standard for a long time. (Two-piece models are technically new.)
In consequence, there are more 3-piece cranks on the market.
- Irreplaceable Spindle
If the spindle of a 2PC crank beaks, it’s game over, and you have to replace the entire set.
The spindle of 3PC cranks is replaceable as long as you can find a new one.
The good news is that spindles are tough. It’s somewhat common to break a bottom bracket, but the spindle/axle requires some exceptional effort to break it.
The Pros of Three-piece
- Modularity
If the crank arms or the spindle breaks, you can replace the damaged part without having to purchase a new set of cranks.
- Classic
3PCs have been here for a long time and have already proven themselves as very strong and reliable.
- More Options + Lower Price
The Disadvantages of 3 Piece Cranks
- More Tinkering
Since one of the crank arms is detached, it takes a bit more work to mount the cranks.
- Slightly heavier
As already shown, 3-piece cranks are heavier on average.
So, what’s best?
If you want a simple and light crankset that you can disassemble with an Allen key as quickly as possible, 2 piece cranks fit the bill.
If you want a classic BMX crankset with modularity and do not care about having the lightest bike, a 3 piece crank should be more than satisfactory.
As far as strength is concerned, both options will perform very well as long as the quality is good.
Conversions Are Possible But Trucky
You can convert from 2 to 3-piece cranks, but you will have to replace the entire crankset and potentially the bottom bracket.
If the current bearings and sleeves fit the new cranks, you should be able to use the existing bottom bracket.
Stay Away From 1 Piece Cranks
Оne piece cranks are the cheapest but unfortunately the weakest too. For that reason, they are found on children’s bicycles as well as low-quality models. 1 piece cranks stopped being used for serious BMX riding during the late 80s.
The main incentive to drop them was their weakness plus the fact that they are difficult to tighten.
2.5-piece Cranks Exist Too
2.5-piece cranks are in between 2 and 3PC models.
One of the arms comes attached to the spindle via a bold-based wedge system. If you want, you can remove the crank arm.
Many people prefer 2.5-piece cranks because they offer the benefits of both worlds.
Don’t Obsess!
Far too many people get caught in the search for the ultimate bike.
We want everything to be perfect, from the chainring bolts to the grips and become so obsessed with an illusory image that we forget the most important part – riding.
It’s essential to have quality components, but past a certain point, the tinkering converts from helpful action into overthinking.
Go ride.
Until next time,
Rookie
Leave a Reply