Author Topic: How to install a Mid BB (Simplified and pic heavy)  (Read 2982 times)

Offline SoKyFlow

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How to install a Mid BB (Simplified and pic heavy)
« on: August 29, 2012, 12:20:26 AM »
Hey guys, since getting back in to flatland, I've had a helluva time getting adjusted to new tech and such in the BMX world.  While getting this new bike together, I've run in to issue after issue and all of it just due to my lack of knowledge.  Well, not so much a helluva time, just thinking I know it all and raging shortly after.  After my hassles trying to get a Mid BB installed, I decided to do it the right way and throw up a How-To, hopefully helping some others avoid some irritation, while offering a cheaper alternative than a trip to the bike shop.   I've read through the other How-To posted here, but it didn't cover the cheap make shift bearing press.

This How-To will cover how to install a MidBB with 19mm spindle.  I assume the installation will differ only slightly on a different size spindle, but you'll need a different size bolt.

Tools needed:

Wrenches - I used a 10" and a 12" crescent wrench.  Any 1" wrenches will work though.

To make this install as smooth as possible, you will need to make a trip to the hardware store for a few parts. 

3/4" x 4 1/2" threaded bolt.
3/4" nut
Three (3) 3/4" washers (must be at least 2" in diameter)

This is all I used for a make shift press for easy installation.    I picked these up for about $4 at Lowe's.

The install:

First step is greasing everything up.  This is required, as everything will fit together much smoother and reduce any risk of damage.  I grease the bb as well as the outer edge of the bearings.

Next is to insert one (1) bearing and run your bolt through.  Ensure you have washers on both sides to keep equal pressure over the bearing to prevent any damage.

Now it's time to tighten it down.  I actually bought two new crescent wrenches for this.  They ran about $40 at Sears.  You could probably borrow some, but any excuse to buy more tools is good enough for me.  Tighten it down slowly and make sure the bearing is going in straight and smooth.  Otherwise, you'll end up busting sh*t.  Busted sh*t is more money spent on new parts.

While I was doing this, the misses was sitting around watching.  I explained why I wasn't using a mallet to hammer these in.  ...just me I guess, rambling about whatever.  She was kind enough to go in depth about how there is only one thing that needs to be hammered.  (Pic posted at her request of course)

Anyways, back on topic.  Once tightened down, my bearings were flush.  Due to lack of a true standard in the industry, yours may not.  I don't know.  Pay attention.  If something seems as it's about to break, don't assume it'll be ok.

Be sure and put that spacer in.  Some people use them, some don't.  I couldn't think of any real reason not to, so I used it.

As with the first bearing, same thing here.  Grease it up, set it in nice and even, put the washer and nut on and tighten it down.  Slowly.

....and you're done.

I hope this will help someone else along the way.  Feel free to correct any mistakes or mention anything I left out.


« Last Edit: August 29, 2012, 12:25:16 AM by SoKyFlow »

Offline tod miller

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Re: How to install a Mid BB (Simplified and pic heavy)
« Reply #1 on: August 29, 2012, 04:16:11 AM »
You could even grease the threads on the bolt you use for the press.  That's just me...I was taught to grease every thread. 

But yeah man, great job.  Thanks! 
"A puppet no more!"

Offline SoKyFlow

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Re: How to install a Mid BB (Simplified and pic heavy)
« Reply #2 on: August 29, 2012, 06:26:07 AM »
Yea, good tip.  Lube everything.  Same goes for everything, flatland or otherwise.


Offline wolverines

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Re: How to install a Mid BB (Simplified and pic heavy)
« Reply #3 on: August 29, 2012, 07:14:30 AM »
Someone PBR this man ASAP! :beer: