Replacing my Bottom Bracket

thamacdaddy

I have an 02 kona cindercone that I have been using for the last 8 months for commuting. Given I really push it up the hilly route I can now feel my bottom bracket going.

Basically I felt it at the start of this week and though my pedals might need tightening then tested it and the whole crankset will move up and down slightly. Its annoying to ride with and I know its bad.

Problem is I need to replace it obviously but have never done this before. I have the tools and know its a case of removing the cranks pulling the bracket and installing the new one. I may get an LBS to do it for me but I need to get the bracket really or at least know what I need.

Its stock and so is listed as TH 7420 ST bottom bracket which so far I think I can find out is a specialized OEM and has the measurements 68mm by 113mm. Would someone who knows their stuff be able to confirm this and if this is the case would these be possible replacements?

http://www.chainreactioncycles.com/Mode ... elID=22255
http://www.wiggle.co.uk/ProductDetail.a ... %20Bracket
http://www.allterraincycles.co.uk/product/9826.html


And my bike spec (some upgrades but bottom bracket and crankset is the stock listed here)
http://www.konaworld.uk.com/bikes/2002/cindercone.html

Andy B

Shimano every time, the UN73 is even better than the UN53/54, which is still damn good.

nicklouse

well the Allterrain link has a correct pic`ture but the name is all wrong.

the only way to be sure of the axle length is to measure the existing one. But the bb width should be 68mm.

is it the original bb?

thamacdaddy

Great and just watched some videos on bottom bracket replacement and to be honest it looks easier than when I took apart my rear derailer and rebuilt it last week (jockey wheels needed sorting).

Just need someone to confirm I am right with the TH7420ST being 68 by 113 size so I can get the right size....it took some finding but would be nice to have it confirmed by someone who knows.

EDIT: Yes its the original BB as listed in the kona spec and the firex Cranks. Plus if you could just let me know what the sizes actually are a measurement of I can then go measure. I was asuming rather than knowing.....not always a great idea.

Thanks all the help is really appreciated

nicklouse

well the TruVativ Firex SX could have been speced with either a 108 or a 113mm axle dependent on the chain line wanted, but 113mm is 99.9% normal.

stumpyjon

68mm will be the size of the bottom bracket shell on the frame and the 113mm will be the length of the axle.

thamacdaddy

Thanks all as an update got my new BB (though to be honest in another 6 months or so after this I am going hollowtech) and after much effort got my crankarms off. I then managed the left none drive side of the BB which pulled out the spindle etc leaving the right side cup in place.

I can see there is some rust on the inside (its not been touched in 6 years) and the right side simply won't come off. I am currently soaking the area in WD40 and have a rubber mallet to try and hit the large 32' tool that connects to my bb tool.

If I can get hold of a vice I might be able to do what park tools advises but right now I am left with a bike thats pretty stripped down. SOmething tells me I am back to public transport for work tomorrow.

All those years of neglect are biting me on the ass right now!

nicklouse

you are turning it the correct way?

thamacdaddy

its drive side and I am going clockwise.

From what I can see from park tools and other areas I have read this is correct I believe.