Bottom bracket replacement (help please)

OdemodeEpaybre

I have a Specialized Allez Sport that I use for commuting and winter. Recently its started to make an awful creeking and cranking sound when I out pressure on the pedals. I've checked and it seems like its the bottom bracket. I've had for 1.5 years and rode it through two winters so I'm gathering its due.

Now I'm not really mechanically minded but I'm eager to learn. I need to know what bracket to replace it with. I've read that its the 68mm but I'm not sure whether its the Italian or English thread that I need. Am I right it saying that the Hollowtech II is the right tool for it to?

Any advice would be greatly appreciated.

Heres a pic of the current bracket with what I think is the model number?

chris_bass

two winters is pretty good going for a BB in all conditions.

that'll be an english thread, if you want to replace it yourself you'll need a few specialist tools.

first you'll need one of these
http://www.chainreactioncycles.com/shim ... p-prod3785
which removes the plastic bolt from the non drive side crank.
you'll also need something like this
http://www.wiggle.co.uk/park-tools-holl ... cket-tool/

which removes the bottom bracket.

first loosen the bolts on the non driveside crank, remove the plastic bolt with the above tool. remove the chainset, you may need to hit the end with a rubber hammer to get it going. then remove the bottom bracket using the second tool and a ratchet.

then do the above in reverse with the new BB.

mitchgixer6

Yip good advice above. Just remember to lift up the small plastic safety tab that's in the gap that the bolts close on the non driveside arm.

Also remember that the thread for the driveside cup of the bottom bracket is reversed, so you'll need to turn it clockwise to loosen.

OdemodeEpaybre

A friend has this tool. Would this be compatible?

http://www.chainreactioncycles.com/cycl ... -prod42809

keef66

OdemodeEpaybre wrote:

A friend has this tool. Would this be compatible?

http://www.chainreactioncycles.com/cycl ... -prod42809

That's the cookie! The little plastic thing is for the end cap on the non drive side crank. All you need in addition is an allen key to undo / tighten the pinch bolts on the LH crank arm.

southdownswolf

The BB that's on your bike will be a Tiagra 68mm (English). There is not a specific Sora BB, but Tiagra or 105 whichever cheaper will be fine.

OdemodeEpaybre

Thanks a lot!!! Got these on order now.

arlowood

Just remember that when you reassemble the chainset, the small plastic cap that you removed from the end of the non-drive side axle/spindle is there to pre-load the bearings and should not be done up too tightly.

A useful sequence to adopt on assembly is:-

1, Install new Bottom Bracket (taking account of the reverse thread for the drive side cup)
2. Insert the cransket spindle and make sure it is properly seated against the drive side bearing cup (In my experience the spindle fit though the bearing cups is usually quite tight and you will need to "persuade" the spindle to bed home by some firm strikes with a wooden or rubber mallet)
3. Slide the non-drive crank arm onto the splines - but do not tighten the securing bolts yet
4. Insert the plastic plug and tighten it progressively while checking the rotation of the crankset. Once you feel that there is some resistance to rotation back off the plug by about a quarter turn.
5. Push down the plastic fillet which sits in the slot where the LH crank bolts are located then tighten the securing bolts in sequence until they reach the required torque

mitchgixer6

Remember also to add some grease on the spindle and threads on the cranks.