gbb
Squire
- Location
- Peterborough
So, i'll start again. Bianchi / FSA Megaexo BB, i noticed some slop in the cranks. Ooer, BBs gone ( i thought).
I gather the Megaexo BB is not well regarded, but what i found can save you some money bearing in mind
online prices for a new BB are IRO £40 to £45.
Having removed the BB cups, (they're cranked up tight onto the BB shell) its not the bearings that have gone, its the endcaps or covers if you prefer.
They're made from plastic and they are a tophat section. The tube section had worn and seperated from the washer section allowing the tube that supports the crank to slide into the BB cavity, therefor giving the crank spindle no support therefore allowing the slop.
Like this, new one and damaged one beside...(apologies for the poor quality of some photos)
For most people i guess they'd replace the whole thing. If you're on a budget or like to DIY, its not a major job
if you have a cup removal tool or a diy bearing extractor and a little time.
The important thing is, how many people are replacing the whole BB when its possibly just the covers that have disintegrated.
Its also possible to just remove and replace the covers IF the bearings appear ok. If thats the case, disregard the instructions on bearing removal etc.
This is an excellent opportunity as well to upgrade your bearings.
Standard bearings are 6804-2RS. They cost less than £2 each on ebay etc. You can fit 61804-2RZ which are
deep groove, low friction bearings. Obviously they're more expensive. You could go the whole hog and fit ceramic hybrids
but they ARE expensive.
There's many permutations of the same bearing.
6804...standard bearings
61804..deep groove, reputedly better
-2RS..standard seals
-2RZ..low friction seals
The SKF 61804-2RZ, you really can feel the difference between them and the standard bearings, they roll so much
more freely, even just in your fingers.
You'll need 2x 6804-2RS, or 61804-2RS or 61804-2RZ (the better low friction ones)
2x Tophat covers. I got mine from UKbikestore for about £8 for two, postage included. Mine were the 19mm dia ones.
Beware, make sure yours are the same.
If you go for the standard bearings and covers, you'll be looking at IRO £12 tops for the lot.
Heres a pic of the cups, bearings, seals and diy extractor.
I used a stanley blade to remove the tophat covers. Slip the point of the blade CAREFULLY under the cover,
work it in so you get maximum blade area to extract the cover without damaging the o ring. It does pop off, but
not easily.
Perhaps you're better off sacrificing them and fitting new ones..or at least being prepared and having some as spare.
There is a tool for removing and installing the bearings, but you can fabricate your own.
You need a piece of steel tube, wide enough on the ID to allow the bearing to pass, and wide enough on the OD to
allow the cup to sit on it.
Ideally it wants to be 45mm od (or larger) and 40mm ID. The tube only has to be 1 inch deep.
An 8 mm heavy washer, 45mm wide or bigger.
8mm bolt and nut. Mine was 60mm long...shorter may do depending on the length of you steel tube.
A 8mm heavy washer about 20mm wide. That'll sit against the bearing on the inboard side.
With the combination of these, you can extract and install the bearings, just flip the tube from one
side of the cup to the other.
The bearings are held with some locking compound, but its not high strength, mine went after a little pop
then i pulled the bearing out quite easily.
Here's the diy extractor fitted to extract the bearing...
Put a little loctite round the outer edge of the new bearing and either with your diy tool, pull it into the cup
making sure it is going in straight...or at this stage, you could just use an oversized washer, a mallet and a block of wood so's not to damage the cup. The bearing went in quite easily. The bearing does stand slightly proud on the outboard side when fully installed.
I flipped the steel tube over now so it can pull in the new bearing. Obviously you need to use the bolt and heavy washers too..
Make sure the o ring is installed on the new (or original) tophat cover, i smeared some grease on the inside of the cover to repel water etc, then push in the cover into the bearing, then liberally smeared grease into the cup
on the inboard side.
Again, be aware, the more grease you pack in the outboard side, between the bearing and the cover, the more friction you create.
Bearing fitted on one, bearing and cover fitted to other...
Job done...do the other one, then fit the overhauled cups onto the bike.
Its one of those jobs you can do yourself, with a few tools and bits. They cost of course, limiting the savings your first time overhaul, but once you've got them.
Just thought i'd share for anyone that's interested.
I gather the Megaexo BB is not well regarded, but what i found can save you some money bearing in mind
online prices for a new BB are IRO £40 to £45.
Having removed the BB cups, (they're cranked up tight onto the BB shell) its not the bearings that have gone, its the endcaps or covers if you prefer.
They're made from plastic and they are a tophat section. The tube section had worn and seperated from the washer section allowing the tube that supports the crank to slide into the BB cavity, therefor giving the crank spindle no support therefore allowing the slop.
Like this, new one and damaged one beside...(apologies for the poor quality of some photos)
For most people i guess they'd replace the whole thing. If you're on a budget or like to DIY, its not a major job
if you have a cup removal tool or a diy bearing extractor and a little time.
The important thing is, how many people are replacing the whole BB when its possibly just the covers that have disintegrated.
Its also possible to just remove and replace the covers IF the bearings appear ok. If thats the case, disregard the instructions on bearing removal etc.
This is an excellent opportunity as well to upgrade your bearings.
Standard bearings are 6804-2RS. They cost less than £2 each on ebay etc. You can fit 61804-2RZ which are
deep groove, low friction bearings. Obviously they're more expensive. You could go the whole hog and fit ceramic hybrids
but they ARE expensive.
There's many permutations of the same bearing.
6804...standard bearings
61804..deep groove, reputedly better
-2RS..standard seals
-2RZ..low friction seals
The SKF 61804-2RZ, you really can feel the difference between them and the standard bearings, they roll so much
more freely, even just in your fingers.
You'll need 2x 6804-2RS, or 61804-2RS or 61804-2RZ (the better low friction ones)
2x Tophat covers. I got mine from UKbikestore for about £8 for two, postage included. Mine were the 19mm dia ones.
Beware, make sure yours are the same.
If you go for the standard bearings and covers, you'll be looking at IRO £12 tops for the lot.
Heres a pic of the cups, bearings, seals and diy extractor.
I used a stanley blade to remove the tophat covers. Slip the point of the blade CAREFULLY under the cover,
work it in so you get maximum blade area to extract the cover without damaging the o ring. It does pop off, but
not easily.
Perhaps you're better off sacrificing them and fitting new ones..or at least being prepared and having some as spare.
There is a tool for removing and installing the bearings, but you can fabricate your own.
You need a piece of steel tube, wide enough on the ID to allow the bearing to pass, and wide enough on the OD to
allow the cup to sit on it.
Ideally it wants to be 45mm od (or larger) and 40mm ID. The tube only has to be 1 inch deep.
An 8 mm heavy washer, 45mm wide or bigger.
8mm bolt and nut. Mine was 60mm long...shorter may do depending on the length of you steel tube.
A 8mm heavy washer about 20mm wide. That'll sit against the bearing on the inboard side.
With the combination of these, you can extract and install the bearings, just flip the tube from one
side of the cup to the other.
The bearings are held with some locking compound, but its not high strength, mine went after a little pop
then i pulled the bearing out quite easily.
Here's the diy extractor fitted to extract the bearing...
Put a little loctite round the outer edge of the new bearing and either with your diy tool, pull it into the cup
making sure it is going in straight...or at this stage, you could just use an oversized washer, a mallet and a block of wood so's not to damage the cup. The bearing went in quite easily. The bearing does stand slightly proud on the outboard side when fully installed.
I flipped the steel tube over now so it can pull in the new bearing. Obviously you need to use the bolt and heavy washers too..
Make sure the o ring is installed on the new (or original) tophat cover, i smeared some grease on the inside of the cover to repel water etc, then push in the cover into the bearing, then liberally smeared grease into the cup
on the inboard side.
Again, be aware, the more grease you pack in the outboard side, between the bearing and the cover, the more friction you create.
Bearing fitted on one, bearing and cover fitted to other...
Job done...do the other one, then fit the overhauled cups onto the bike.
Its one of those jobs you can do yourself, with a few tools and bits. They cost of course, limiting the savings your first time overhaul, but once you've got them.
Just thought i'd share for anyone that's interested.
