bottom bracket torque

[gasinayr]

to what torque do you tighten bottom bracket cups

 

[presta]

Best to look up your specific BB, but typically 35-50Nm.

https://www.parktool.com/en-us/blog/repair-help/torque-specifications-and-concepts
https://si.shimano.com/en/pdfs/dm/TORQUE/DM-TORQUE-00-ENG.pdf

 

[FrankCrank]

Never used a torque wrench on a bike, just go by feel.

 

[ianrauk]

Just by feel. Unless the bottom bracket has a plastic cup then I give it some.

 

[Ajax Bay]

Depends what you mean by 'cups'. Cup and cone bearings have cups. Outboard BBs for a 24mm Shimano spindle might be colloquially called 'cups' but . . . There is no set torque for the left side cup: too tight and the cup will bind on the bearings. The right side cup is as tight as you can, plus a bit. Often never needs removal.

 

[cyclintom]

Never used a torque wrench on a bike, just go by feel.

That is a bad idea on carbon fiber bikes.

 

[FrankCrank]

That is a bad idea on carbon fiber bikes.

Yup - too used to bashing things with hammers - only steel and aly for me

 

[Ming the Merciless]

That is a bad idea on carbon fiber bikes.

Fragile things

 

[Big John]

Fragile things indeed. Saying that, I've had my carbon fibre bike for must be 17 ISH years now and I've never invested in a torque wrench and it still runs fine despite having every part replaced over the years. The damage on my bike has always been caused by a crash or similar catastrophic event. They don't bend or dent, they crack or snap. Well, that's what's happened to mine. I only bought carbon because everyone else that I raced with had carbon. Purely a personal choice but I wouldn't buy another one but then i don't need one. I'm happy riding Reynolds 531 at a much more leisurely pace.

Edit: My carbon bike is very much like Triggers Broom lol.

 

[gasinayr]

tightened my bottom bracket to 46 n/m So far all is good.

 

[Ajax Bay]

Nm

 

[Anton K]

Depends what you mean by 'cups'. Cup and cone bearings have cups. Outboard BBs for a 24mm Shimano spindle might be colloquially called 'cups' but . . . There is no set torque for the left side cup: too tight and the cup will bind on the bearings. The right side cup is as tight as you can, plus a bit. Often never needs removal.

Hi. I`m new there. Noticed very important words by you. Many suggest to tighten left cup (in cartridge bb) either tight or just less then the drive cup. And through many attempts i opened up the left one needs almost zero torque, but to be kind of shut, never left free or tightened only with a tool in bare hand (with no wrench). Now i`m testing with application of some grease inside the cup, it helps to feel the right moment of the cup being shut (between only touching and slight overtightening). I want to pull some more words from you, if you discovered this "binding on''.
P.S. Driveside cup shouldn't be overtightened as well, my experience. Tested them tight and it`s squeezing the bearing inside.

 

[Ajax Bay]

I am torquing about 'proper' cup and cone BBs: ones with a lockring on the left hand side when I said:
"There is no set torque for the left side cup: too tight and the cups will bind on the bearings. The right side cup is as tight as you can, plus a bit."
With 'inboard' 'cartridge BB (eg UN-300), the torque recommended is on the sheet (50-70Nm; about 25kg wt on a 10" spanner - see also @ianrauk "give it some"; care keeping 20-spline tool engaged).
Same for 'outboard' BBs (35-50Nm). Both with grease. (Pages 17 and 13)
https://si.shimano.com/en/pdfs/dm/MDFC001/DM-MDFC001-06-ENG.pdf

 

[Anton K]

Than you for responding, Ajax Bay. I love cup and cones as well. Discovered it is important not to overtorque the retainer (?) on the left cup. Otherwise the bearings will travel kind of oval path, not circle. Right one, imho, should be just shut to the frame with force, but no additional moves, only one strong single effort.
Thank you again