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Plastic BMX Bottom Bracket?

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Plastic BMX Bottom Bracket

A plastic BMX bottom bracket? Over the years we’ve seen a number of parts on a BMX bike get the plastic / nylon treatment from barends to pedals, pegs, hub guards and even seat posts. In most cases, it works pretty well, but obviously the parts can wear faster than metal. We were just made aware of this new one in Brant Moore’s BMX News video where he pointed out a company called Karma BMX that is currently working on this plastic Mid bottom bracket. Their Instagram Post says “Less weight and no more troubles with bearings…” as the reasoning behind it, but we’re honestly not too sure how well this will work.

Obviously your cranks need to spin and over time that metal on plastic would likely wear down causing a wobble. It could also blow out pretty easy considering that a large portion of the impact from drops and such transfer into your cranks / bottom bracket. The other question this leaves is how well you can crankflip with something like this? No bearings means when the cranks spin, it’s just friction that would slow the cranks down, which could maybe be a good thing if you don’t want them to spin fast, or you don’t want your cranks moving during tricks like tailwhips.

The next thing is that it appears to have the cone spacers built into it as well, which means when the cranks are tightened down, they wouldn’t have anything to spin on, so that would also keep the cranks from spinning, kind of like if you over tighten the cranks down with the wrong size spacer.

We’re honestly curious how well this would actually work. We have our doubts that it would hold up or last as long as traditional bearings, but then again who would have guessed plastic pegs and pedals would have become the norm? We also want to see this installed to see how it looks.

What do you think? Let us know in the comments below!

[Read more…]

Importance of the Bottom Bracket Spacer

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Have you ever wondered why there is a spacer in your bottom bracket? There’s a good chance some of you have chose not to use one or completely forgot to install it and just left it off once you already had the bearings in your frame. Well, it turns out that little tube is more important than you might think. Brant Moore decided to put together a little video explaining the importance of a bottom bracket spacer and what happens if you don’t install one.

“There’s one part that a lot of people make the mistake of not using when building their bikes.
This one part will make your bike smoother and less creaky and can even help with a trick or two!

Watch the video to find out and make your bike better!

Odyssey Write Up”

Full text from the video below courtesy of Brant Moore!

“So what exactly is a bottom bracket spacer and what does it do?
It is a spacer that goes between bottom bracket bearings to reduce bearing strain by giving the bearings something to always tighten or push against.

To start, what is a bottom bracket bearing composed of?
It is an, Inner race, steel balls and an outer race.
The outer race is what touches the frame, the inner race is what goes around the spindle. Its worth mentioning too that the bearing is only meant to spin around one axis.

Since the bearings can only be pushed into the frame so far before the outer race is stopped, having no spacer means that tightening the cranks pushes the inner bearing races toward the center of the frame and each other.

Basically the outer race cannot move so the force on the inner race is constantly trying to separate the bearing.
This is called side loading.

As bearings start to wear, the tolerances between steel balls and the races grow, allowing them to move independently of each other. If there is any movement between the bearing parts you will most likely hear it when you pedal.

On top of this, having no spacer allows pedaling to put other forces on the bearings.

Each rotation of the cranks puts both forward and backward force on each bearing during the entire rotation and tries to make the inner bearing races wobble off axis. In general this makes for unnecessary drag on the bearings when pedaling.

With cranks getting beefier and spindles growing, bearing size has had to shrink and there is less flex in the cranks or spindle. Less flex equals more stress on these smaller bearings when pedaling. Unless you have a bottom bracket spacer between the bearings.

Bottom bracket spacers remove the different forces on the bearings by placing something between the inner bearing races. This means that when the cranks are tightened, there is something to tighten against. Rather than constantly pushing the inner races toward each other with nothing to tighten against, the force is distributed evenly, and the bearings are not as stressed by tightening or pedaling.

Imagine it like this, if you have just an axle in your fork dropouts with no hub and you tighten axle nuts against the dropouts, the dropouts would have nothing to tighten against and would bend toward each other. Add in the hub and that empty space is filled, giving the dropouts something to tighten against.

So not only will having a spacer eliminate side load and quiet your creaky bottom bracket, it will also make for a smoother pedaling experience.

Another thing this can be good for is the ability to have tight cranks and still be able to crank flip.
With the inner bearing races in alignment with the outer races and tight against something on both sides, the tightness of the cranks doesn’t have an affect on how they spin.
So if you’ve ever wondered why your cranks wont spin with a loose chain and without loosening your cranks, this is probably the reason.

Some frames have different width bottom bracket shells that will need different spacers, however if you buy a complete bottom bracket set up it should come with everything you need for the different width shells.
Common widths are 68 and 73mm.
My profile bottom bracket came with both a 68mm spacer as well as a 5mm spacer to make 73mm.

To know what width your bottom bracket is, simply measure the tube from end to end as shown.
Another side note, Odyssey has a great write up from 2004 about this topic on their site that I will link below.

So what do you think?
Are bottom bracket spacers important? Is it worth the trouble of taking out your bearings? Or do you not care?

I will say that it was absolutely worth it for me and only took about 15 minutes. By putting the spacer in my frame and oiling the chain, all creaking was completely removed, pedaling became smoother and crank flips spun much easier, all within a matter of seconds.“

Kink BMX

How To Install A Press Fit Bottom Bracket

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You really should know how to properly install a press fit bottom bracket on a BMX bike…

How to Install A Press Fit Bottom Bracket BMX

In a world where BMX bikes have been simplified A LOT since their inception and constant innovation, there are plenty of things an average person can do to work on and maintain a BMX bike. Unfortunately, sometimes things are a little more complicated than they might seem. The guys over at The Merged have noticed plenty of How To videos explaining just how to install a set of BMX cranks, but they seem to always breeze on by the installation of a bottom bracket. With the vast majority of BMX frames taking the press it Mid bottom brackets these days, they decided it was time for a How To explaining the fine details of installing these bearings that keep your cranks spinning. Although it might seem as simple as “bash the shit out of the bearings until they are in place”, there are a few details you might not know are important to the process. You can check out the full how to explaining what it takes to install a press fit bottom bracket over on The Merged Website — Pressing Issues: How To Install a Press Fit Bottom Bracket

Flybikes – 2017 Dark Gold Parts

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flybikes-dark-gold-2017-bmx-parts

It looks like Fly Bikes will be keeping their Dark Gold color around for another year! Here’s a sneak peek look they dropped online earlier today giving us a look at all the parts that will be available in the color including their new Lunar Rim and the Volcano front and top load stems. You can also find the Piramide rim, Tractor Sprocket and Tractor XL Sprocket, Roey stem, Mid bottom bracket, headset and Tripod post! Expect these all to be available at the end of October / early November with the rest of their 2017 product.

We want to hear from you! Let us know what you think in the comments below!

VISIT: FRONT PAGE // DAILY SECTION // BMX COLOR APP // BMX VIDEOS // RANDOM // BMX Games

Kink BMX

Flybikes – Space Grey Colorway

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flybikes-space-grey-color-bmx-parts

Flybikes keeping the 2017 previews coming. This time around we get a look at their parts in their new Space Grey colorway. Based on the photo, we can see their Piramide rim and the new Lunar rim, the Tractor and Tractor XL sprocket, Roey stem, Tripod seat post, Rotar bottom bracket and headset and the new front and topload Volcano stems. Really digging the clean look that this color gives everything! It sounds like the new 2017 products from Flybikes will be dropping at the end of October / early November, so keep your eye out for it if you’re digging this.

flybikes-space-grey-color-bmx-sprocket-bottom-bracket

The Rotar bottom bracket, Tractor XL sprocket and Dolmen 2 cranks all paired up.

flybikes-space-grey-color-bmx-tractor-sprocket

The Tractor Sprocket in the new Space Grey color.

flybikes-space-grey-color-bmx-tractor-xl-sprocket

The larger version of the Tractor sprocket, the Tractor XL sprocket in the new Space Grey color. This sprocket is unique because it’s 16mm thick in the center, eliminating the need for spacers and a bottom bracket dust cover, then tapers down to 6mm at the teeth like a traditional sprocket. Clean and simple.

We want to hear from you! Let us know what you think in the comments below!

VISIT: FRONT PAGE // DAILY SECTION // BMX COLOR APP // BMX VIDEOS // RANDOM // BMX Games

Note: This site contains affiliate links and we could recieve a small comission that supports this site if you were to make a purchase on their websites using our links for no extra charge to you.
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