In this thread we are going to go over all the do's and don'ts when it comes to purchasing a new complete bike. After reading this, you will be equipped with all the knowledge necessary to pick out your own new BMX Bike!
First and fore most, we wouldn't recommend spending money on a bike unless it includes at least the following essentials;
Full-Chromoly Frame, Forks, & Handlebars
Other options include Hi-Tensil Steel parts which are renound for breaking very easily. It's better to spend the extra $100 or so for the Chromoly model than to spend $400+ on a new frame set when the Hi-Tensil gives out. Also be mindful that some frames and forks are half-Chromoly and half-Hi-Tensil, which is just as bad as full-Hi-Tensil.
These are rather critical because the hubs on your BMX will require more maintenance than most other parts. Opening up a hub full of loose-ball bearings is not only a hassle, but a sure-fire way to lose essential pieces of the hub. "Semi-Sealed" is NOT the same as Sealed. Sealed bearings are easier to maintain, require less maintenance, and are easy to find replacements for, all while spinning noticeably smoother. Also, aftermarket hub sets are $200+, so they're not something you want to replace shortly after purchasing a bike.
3-Piece or 2-Piece Cranks
Most bikes will come with 3pc cranks, and some may even come with 2pc or 2.5pc. Both options are essentially the same, with a main bottom bracket spindle and tubular Chromoly crank arms. This design is far superior, and easier to work on, than a 1pc crank set. 1pc crank sets are notorious for bending and snapping after short periods of time, and in order to upgrade to a 3pc/2pc from 1pc, you will have to buy a new bottom bracket ($20-30) aswell as the crank set ($75-150+)
These are mostly essential in the rear wheel since it will likely see the most abuse, but generally a good bike will come with Double-Wall Rims front and back. These are far stiffer & stronger than single wall rims. They are less likely to be dented or flat-spotted, or worse. & for the most part they will keep you from needing to have your wheel trued (straightened) every other week, which is very costly if you can't do it yourself.
These are all things considered to be essential when purchasing a bike, due to a strength-to-cost ratio.
There are also many cheaper parts on the bike that might not matter as much to a beginner or someone buying a complete on a budget. This is a list of parts and specs that are less important, & are easier and cheaper to upgrade over time or as things break;
You will typically see two kinds of headsets on a BMX, Standard & Integrated.
Typically, you will want an integrated headset, as this means that the Frame is equipped with sealed headset bearings & is a sign of quality.
However, if you do have a standard headset (with pressed in bearing cups,) you can buy an STI (Standard-To-Integrated) adapter to run sealed integrated bearings without any loss in strength or function.
Mid or Spanish Bottom Bracket
Quite similar to the headset, bikes will come with one of 3 options for bottom brackets. American, which typically utilizes a threaded spindle, removable bearings cups, and loose-ball bearings. Mid size, which is the most common and uses 2 sealed bearings that press directly into the frame. & lastly, Spanish, which is pretty uncommon, but is essentially the same as a Mid BB.
If you happen to have an unsealed American bottom bracket, you can insert sealed bearings by purchasing and American-To-Mid Bottom Bracket. This will require 2, 2.5, or 3pc cranks and an unthreaded spindle (if you already have 3pc cranks with a threaded spindle, you can purchase just an 8spline spindle.)
When it comes to 2-3pc cranks, the amount of splines (grooves on the spindle/in the spindle boss) can make a huge difference. The most common used ones are 8-spline, 16-spline, and 48-spline. 48-spline cranks eliminate the need for a pinch bolt which makes them less likely to fail around the spindle boss. They are also typically a bit lighter and more comfortable on the ankles. These are what you'll see on most high end bikes.
Getting a bit more technical with the hubs, Female Axles are significantly stronger than Male Axles per size. It is cheaper and easier to replace female bolts if they snap than to replace a whole axle or hub due to breaking a male axle. They also are much less likely to bend or damage the dropouts from grinds.
Typically the ideal set up would be..; Front Hub - 3/8" female Rear Hub Pegless - "Shemale" (14mm axle shoulders with 3/8" female bolts,) OR 14mm female Rear Hub w/ Pegs - 14mm female, OR 14mm male
(We recommend not riding pegs on a rear 3/8" bolt.)
7075-T6 Aluminum Alloy Sprocket
Typically you will want a 7075-T6 sprocket as opposed to a 6061-T6 sprocket. The 6061 material has a reputation for bending easily and wearing down quick. 7075 sprockets typically stay straighter and smoother for substantially longer, and you can find some pretty basic ones for cheap. & for general reference, 7075 is typically superior to 6061 when it comes to bike parts.
CNC'd or Forged Stem
This is one that I feel gets over-looked a lot. CNC machined & Forged stems are far more durable than Cast stems. A cast stem is substantially cheaper, and will hold up fine for most, but they are more likely to crack than one that was cnc-machined or forged.
This applies to the frame, handlebars, forks, and cranks. Typically, higher quality stuff will use heat treated tubing, which is considered to be stronger for BMX. There are also post-weld heat-treated parts, these are generally considered to have super strong welds, as they treat the entire part after welding it. Generally speaking, heat treated parts are going to hold up better than not, and post-weld heat-treated ones even more so.
While having double-wall rims is essential, it is also important to be mindful of the seem (the joint where the rim connects.) Most lower model completes will come with pinned-seem rims, meaning the rim has pins running through the joint, holding it together. These will be fine for most beginners or not-so-serious riders, but are known to pull apart at the seem when confronted with abuse. You can avoid this problem with welded-seem rims, which are typically laser-welded at the seem for maximum strength.
High PSI Rated Tires
There's so many different tires on the market, it's hard to know what's good and what's not. Generally speaking, high quality tires will have a high PSI rating (90-120PSI) and lower quality, cheaper tires will usually have a lower rating of maybe 65PSI or less. That being said, not all high-PSI tires are durable, and not all low-PSI tires are all that bad. Use your better judgement with this information & keep in mind that all tires need replaced eventually anyways.
More of just a friendly warning, considering pedals are typically ridiculously cheap. Clear plastic pedals are renound for cracking/snapping super easily. The clear plastic compound is a lot more brittle than a solid colored compound.
Time to Pick Your Bike
Using all this information, you should be ready to pick out your new ride based off of your own personal interest. Things like color schemes, company, and size/specs are what will make your bike your bike.
Questions? E-mail them to firstname.lastname@example.org
When should I buy my bike? I would advise to do your bike shopping around the beginning/end of the year, as you can easily find higher-end models on sale for $100-300 off. Less money, better bike, can't beat it!
Isn't some chromoly better than no chromoly? Not necessarily. The chromo tubes may be more dent proof or may be lighter, but you're not going to get a very strong weld from welding chromoly to hi-tensil. Plus, what's it matter if the front end is chromoly when the dropouts snap off?