How To Service And Install A Press Fit MTB Bottom Bracket | Mountain Bike Maintenance

How To Service And Install A Press Fit MTB Bottom Bracket | Mountain Bike Maintenance


– There’s nothing more annoying than a creaking mountain bike. One of the things that can
cause creaks are loose bolts, another worn out bushes,
sometimes even a dry chain. Today, we’re going to be looking at the press-fit bottom bracket. Press-fit bottom brackets,
while simple and effective, can be prone to creaking in the long term. This is how you cure that. The biggest cause of
creaking bottom brackets with a press-fit design
tends to be the fact that it’s not been installed correctly. It’s absolutely essential that
the bearings are completely flush with the frame and
in line with each other. Any slight movement or
deviation can lead to creaking. There are two types of
press-fit bottom bracket: high-end alloy options
or the common nylon unit. Blake’s bike’s got a nylon
Shimano bottom bracket in here, and we’re going to
simply remove that today and reinstall it,
showing you why it creaks and how to stop it. Before we get started removing the bottom bracket from the bike, make sure you check everything
else around the crank area. Check your crank bolts, chain ring bolts, and if you’ve got a design
where the spider mounts onto the back of the crank,
check that it’s tight. They’re all likely
candidates for creaking. For this job, as we’re
working on a Shimano setup, you need a five millimetre
Allen key to remove the cranks; a Shimano crank tool;
grease, carbon compound or an assembly compound;
bottom bracket rocket tool; bottom bracket installation
press; and a mallet. First things first is removing
the cranks from the bike. First you need a five millimetre
Allen key, or hex wrench, and a Shimano bottom bracket tool. Away we go! So firstly, I’m doing these
five millimetre pinch bolts. These just secure the crank onto the axle. Now using the Park Tool
crank removal tool, there’s a little thumb
wheel on the end here. That’s for removing the pre-loading cap. So, you just locate that into the end of the crank and remove this. This works in the same way
as a Headsettop cap does, it just pre-loads the bearings just to make sure there’s no play. With the Shimano crank
like this, once it’s loose, you can technically take
the crank straight off. You may need to give it just
a little tap with a mallet. Make sure you use the protective end so you don’t damage the crank. Next step is to remove
the drive side crank. Because this is Shimano,
you need to make sure the clutch is off. Notice on Blake’s bike it already is. Remove the chain and
then pull the crank off. So, I’m just going to swing
the lower cage forward, remove the chain, now it’s a case of just
tapping out the axle. And there we go. So this is the Park Tool’s bottom bracket bearing removal tool. I call this the rocket tool because original Headset Tools
were very similar to this, only a lot bigger, and
named the rocket tool. Reason for that is you insert it into the bottom bracket itself, these sprung wings
locate behind the bearing so you can safely put even pressure on the back of the cup. You tap it out using the
metal end of the hammer. Just make sure it doesn’t
fire out across the workshop and under somewhere you’re not going to be able to retrieve it. So, slide the tool straight through, have to give it a little tug
until it locates with a snap. There we go. So, you can feel that’s home
against the back of the cup. Now give this a few firm
taps with the metal end. There we go. So, now you have the
left-hand side of the cup out. It’s the same process for the drive-side. Make sure when you pull this out that the tool stays aligned
on the back of the cup. So, with both cups removed from the bike, you want to clean and inspect these looking for signs of damage. This one on Blake’s bike just looks dusty and dry, to be
honest, and a bit gunky. So, going to give it a complete clean. And the same with the
bottom bracket shell itself. If you can see it inside of here, there’s bits of sand and residue from all the dry riding he’s been doing. Make sure it’s completely
clean before you reinstall. Just cleaning out the
inside of this shell, making sure the surfaces are free of any sort of grit and any muck. So, when you instal a
press-fit bottom bracket, the best way to do it,
the official way to do it, is by using a dedicated
bearing press like this. The reason for that is
you can’t mess it up. You basically push the bearings in and they’re perfectly aligned. A lot of your friends might tell you you can do it with a block
of wood and a mallet, and you can but you’re
never going to be sure that the bearings will be in straight. And that is exactly what leads to a creaking bottom bracket. Depending if you’re
installing your bottom bracket into an alloy or a carbon shell, it affects if you use
a grease or a compound. So, with the alloy shell,
you probably want to use a small amount of grease
but don’t go overboard because overtime the nylon bottom bracket can deform slightly and move, and that’s what causes
those annoying creaks. If you’re unsure about
that, you can also use a anti-seize compound, any
sort of gripping compound. And that stops it moving. For carbon, you shouldn’t
really be using grease because grease is said to weaken the inside of carbon shells. It’s not too much of
an issue to run it dry, but I would recommend using some kind of anti-creak compound. There’s various ones on the
market, so look into that. Just to show you how the bottom
bracket press tool works, what you do is find
the correct spacer that fits your particular bottom bracket. In any of these sort of
kits, you’ll get a number of these type of spacers. That goes straight onto the tool first. Then your first cup would go on and locate onto that spacer. Then you would put the tool into the frame and then repeat on the other side. Before finishing would be the end cup. Then you simply close
this and it squashes it into the frame. So, as you’re tightening
the bearing press, make sure that the bearings are completely flush and in line. You don’t want it going
in at a slight angle, otherwise you’re never going
to get right of that creak. Now it’s the case of just
reinstalling your cranks and making sure all
the bolts are nipped up to the crank taut setting. Then it’s a case of hitting the trails and hoping you’ve got rid of that creak. Now that you got your bottom bracket back in the bike, you’re ready to ride. Hopefully it’s good. If it’s not and it is still creaking and you can’t identify what it is, more than likely, the nylon bb’s still is moving slightly in the frame. If that’s the case,
you can get around this temporarily by using a
sleeve-retaining compound. It acts kind of like a thread lock. It’s a temporary thing
but if your bottom bracket is still in working
condition, it’s worth doing. Don’t forget to subscribe
by clicking right here. If you want to learn a bit more about a full clean and
service on your bike, click down here. If you want to learn about how to keep your whole bike creak free, click up here. Give us a thumbs up if you like the video.