Help needed to replace old bottom bracket

[McSpin]

I have an old bike (27 years old) I use on a trainer and as a "beater" in bad weather. Last year, I put new bearings in the bottom bracket, and they are already shot. I think the spindle is too pitted and I need a new one, but can't find one this size. I was hoping someone could direct me to a more modern replacement bottom bracket that will work on this bike.

The crank is the original Shimano 600 (two chainrings). The spindle is a square taper for a 68 mm bracket shell and 120.4 mm long. I haven't been able to find a replacement spindle this exact length. How important is that? It would seem that a couple mm longer wouldn't hurt anything. Anyway, I don't want to replace the crank, so I'd appreciate a recommendation for something that will work on my bottom bracket shell and this crank. Also, nothing too expensive as this bike isn't worth too much.

 

[gclark8]

If you fill in your Location in the details section, this will make it easy to give you a local contact.

In Aus I can give directions to a BB kit and shaft or a sealed BB.

 

[McSpin]

I'm in the U.S. and don't mind having someone ship it to me. The closest bike shop is 60 miles away and he doesn't have the spindle I need. He might have an updated cartridge-type bottom bracket, but I don't want to have to take my bike to him.

Even if someone tells me the exact replacement bracket that will work, I should be able to find it somewhere.

The spindle length on the old one is: 120.4mm for a 68 mm bottom bracket shell. There is approx. 36 mm of spindle on the crank side.

 

[gclark8]

Any cheap (TH Industries) 118mm or 122mm (121.5) sealed BB should do the job. Get a steel one rather than alloy.

 

[McSpin]

I searched for TH bottom brackets and found some. It said they were for ISIS splined cranksets only. I don't know what that is. Would an old Shimano 600 crankset be considered splined?

 

[dcullen]

try this

http://www.biketoolsetc.com/index.c...=Cartridge/Taper-Spindle&item_id=TA-LN3968122

I'm in the U.S. and don't mind having someone ship it to me. The closest bike shop is 60 miles away and he doesn't have the spindle I need. He might have an updated cartridge-type bottom bracket, but I don't want to have to take my bike to him.

Even if someone tells me the exact replacement bracket that will work, I should be able to find it somewhere.

The spindle length on the old one is: 120.4mm for a 68 mm bottom bracket shell. There is approx. 36 mm of spindle on the crank side.

 

[McSpin]

Thanks for all your help.

 

[gclark8]

try this

http://www.biketoolsetc.com/index.c...=Cartridge/Taper-Spindle&item_id=TA-LN3968122

Purrrfect!

Tange LN39 Cartridge Bottom Bracket,
68mm Shell x 122.5mm Taper Spindle
Price: $19.80
Item #TA-LN3968122: .The Tange LN39 Series bottom brackets feature a steel body, steel cups, and a steel spindle with standard 8mm crank bolt threads. Very durable replacement bottom bracket. 68mm shell width, 122.5mm spindle length, 315 grams. Made in Japan.

All Tange bottom brackets feature standard English (BSA) threads.

You will need a couple of BB bolts to fix the crank arms on.

 

[dcullen]

These are nice
http://www.biketoolsetc.com/index.c...ts&sc=Crank&tc=Crank-Arm-Bolts&item_id=SG-KPB
I have these and like them
http://www.biketoolsetc.com/index.c...s&sc=Crank&tc=Crank-Arm-Bolts&item_id=US-QR8S

Purrrfect! You will need a couple of BB bolts to fix the crank arms on.

 

[McSpin]

Purrrfect! You will need a couple of BB bolts to fix the crank arms on.

I'm guessing that the bolts that went into my old spindle would fit, or is that not the case?

 

[gclark8]

I generally use new bolts in a new BB.

 

[kspangler]

This might sound stupid but, how do you know if a BB is going bad. I had my bike in for a tune up and they said the BB is showing wear, but not yet ready for replacement. I asked a specific question, "...how do you know when it needs replacement..." The answer sounded like a non answer to me - I can't rememer the exact words, but trust me it was a "non answer".

The only sympton I've felt was what I would call some play coming from the BB (I think) when climbing hard. This happened to me maybe 5,000 miles ago and they just tightened it slightly and it went away.

This particular BB has - I'm guessing - 7,000 miles on it. I'm guessing, don't have the numbers in front of me right now - I'm at the coffee shop.

Thanks for all of the help.

 

[McSpin]

Okay, it looks like I'm all set. I'll get the new bolts also. Thanks again for everyone's assistance.

 

[Retro Grouch]

How much space do you have between your chainrings and the chain stay?

If it's only a couple of millimeters, I'd get a Shimano UN54 with a 122.5mm spindle length.
If it's a lot, around 10mm, I'd get the same bottom bracket in the 118mm length.

I don't know of an on line source, but both are in the current QPB catalogue so any LBS can get one for you. I'd assume an on line dealer, like Harris would too.

 

[McSpin]

How much space do you have between your chainrings and the chain stay?

If it's only a couple of millimeters, I'd get a Shimano UN54 with a 122.5mm spindle length.
If it's a lot, around 10mm, I'd get the same bottom bracket in the 118mm length.

I don't know of an on line source, but both are in the current QPB catalogue so any LBS can get one for you. I'd assume an on line dealer, like Harris would too.

Great info! I was wondering how to decide on total length. I guess I'll have to put it all back together so I can see where I've got some room to work with. I suppose I should also make sure the front derailleur can cover whatever direction I move the crank. I'm glad I didn't order it yet - only because I didn't find the time yesterday.