What's this bolt??

[Dekes]

I was taking apart my bike and saw this weird nut at the non-drive side of my BB. It would be nice to unscrew it so i could maybe clean the inside of the bb. I have no clue though whether it's right-hand or left-hand thread or even whether there is thread or not. Has anyone seen this before or does anyone know if this nut can be unscrewed or what it's function is? Thanks.

http://users.skynet.be/team4130/klein1.JPG


http://users.skynet.be/team4130/klein2.JPG

[yard dog]

Lockring indeed. Shimano once made a tool for those old adjustable bb's. If you're gonna dig in there be careful. It can be tough to get good bearing adjustment without said tool.

[Dekes]

Lockring indeed. Shimano once made a tool for those old adjustable bb's. If you're gonna dig in there be careful. It can be tough to get good bearing adjustment without said tool.

the nut itself looks like a normal hex nut with filetted corners. I was thinking of just undoing it with a crescent wrench as my socket wrench can't go deep enough to cover the square axle. There was a rubber/plastic cover over the nut though with "shimano sealed cartridge bearing" written on it. There's also just one lockring on there, the driveside just has a round ending.

Edit: ow and do you know whether this is normal righthand thread or inverse left hand thread? It being a BB made me doubt.

[muddyfox]

You try to turn it one way and if it doesnt undo you turn it the other :eek5:

[Dekes]

You try to turn it one way and if it doesnt undo you turn it the other :eek5:

Hmm, that's really far fetched but maybe it'll work.

I'm just scared that i will damage thread if i do this, because i'm a gay crybaby.

[KenC]

Do you NEED to take it apart? Those cartridge bearing BB's usually aren't meant to be taken apart. If the bearings are rolling smoothly, I wouldn't mess with it. "If it ain't broke, don't fix it."

[Acolyte]

If you open that up, prepare to have a million little bearings on the floor and no chance of getting them back in.

[alexzero13]

Yeah, don't take it apart.

Damn shimano and their special tool bbs. I hate my hollowtech.

[kobrakai]

If you open that up, prepare to have a million little bearings on the floor and no chance of getting them back in.

[Bryan]

My best advice is
Holy shit dude, you're still running a square-taper bottom bracket?!

[MIKE1968]

My best advice is
Holy shit dude, you're still running a square-taper bottom bracket?!

I looked at the picture for a while trying to fig out what it was, been so long since I saw a square taper!

[alexzero13]

Doesn't that weigh a lot?

[brian_E]

first of all that "bolt" is a nut.. second that whole part can be replaced for about $20 these days = even if it is broke don't fix it, get a new one.

[Dekes]

first of all that "bolt" is a nut.. second that whole part can be replaced for about $20 these days = even if it is broke don't fix it, get a new one.

Yeah sorry, my english vocabulary is crap.

The bb works very fine, the reason i want to undo it, is to clean it so it looks new(ish) again. This bb is from my old XC bike, I use ISIS for trials.

[AgrAde]

i read this thread late last night... had a dream about undoing that nut.

[alexzero13]

i read this thread late last night... had a dream about undoing that nut.
I had a dream about nuts

[stickyworm]

XC? Then definitely buy a new one. $15-$20 versus an hour or more of cleaning headaches and in the end it may not work?

[rndm*dv8n]

XC? Then definitely buy a new one. $15-$20 versus an hour or more of cleaning headaches and in the end it may not work?

Actually, on that note, take it apart and then post some pics - I'm curious

[Dekes]

Will do, tomorrow morning

For all it matters, the BB is a shimano UN-54, I forgot to mention it.

[gobigorgohome]

when you take it off try to turn it towards the back of the bike first... i think thats the rule but if it doesnt work dont try to hard

[Dekes]

when you take it off try to turn it towards the back of the bike first... i think thats the rule but if it doesnt work dont try to hard

I've been told elsewhere that the nut is probably loosened by turning it in the direction of the axle rotation when pedalling forward thus being normal thread.

[clifford_bgrddg]

that thing looks like you dragged it from the bowels of the titanic...

[Bryan]

that thing looks like you dragged it from the bowels of the titanic...
:rofl:

[Dekes]

Ok update:

I tried to undo it once again, this time with a longer wrench, but it doesn't move at all. I went to the bikeshop where I bought the bike it came on and that guy said it was pressed on instead of screwd on. I think he's right, though it has these 6 flatted sides like a hex nut :dunno:. It would make sense though, since the UN-72 BB has no nut-like top end on the non drive side. It seems to be a UN-54 thing only. It also had a seal cap over the nut saying 'shimano sealed cartridge bearing' which makes putting a nut on a bit obsolete.