S55 central lock screw „issue“

doughboy · 07-17-2019, 08:54 AM

1. Possibly, but the torque force on the centre bolt to undo is over 600nm and I can't see the hub to bolt friction exceeding that, so yes it moves the failure point to the bolt, but that seems a better option than not! If the hub moves a fraction then it will be "helped" by being held against the bolt head via the capture. So then you have hub friction + bolt friction to over come.

2. The weight of the Litchfield capture was imperceptible when placed in the palm of my hand, literally a few grams, it is obviously made of a lightweight alloy. It's centrally located at the very centre of the rotating crank, again can't see an issue with that when you have large heavy damper pulleys and flywheels hanging of the crank ends!

Fingers crossed, no one US or other, has had a spun hub with a bolt capture fitted....

Proctor750 · 07-23-2019, 08:06 PM

Quote:

Originally Posted by doughboy

1. Possibly, but the torque force on the centre bolt to undo is over 600nm and I can't see the hub to bolt friction exceeding that, so yes it moves the failure point to the bolt, but that seems a better option than not! If the hub moves a fraction then it will be "helped" by being held against the bolt head via the capture. So then you have hub friction + bolt friction to over come.

2. The weight of the Litchfield capture was imperceptible when placed in the palm of my hand, literally a few grams, it is obviously made of a lightweight alloy. It's centrally located at the very centre of the rotating crank, again can't see an issue with that when you have large heavy damper pulleys and flywheels hanging of the crank ends!

Fingers crossed, no one US or other, has had a spun hub with a bolt capture fitted....

Remind me - does litchfield offer just the capture or is that still not in the cards? Not sure how theirs is different from the ones offered here but would like to find out.

Did it line right up or did you have to snug the hub bolt up some to get the hex head "clocked" correctly for the mounting bolts to line up with the capture?

doughboy · 07-24-2019, 06:22 AM

Yes, Litchfield will ship capture overseas I think. Drop them a line.

Main difference is theirs has a built in 17mm hex cap that completely covers the main 17mm center bolt and allows use of a 17mm spanner to turn the motor over if required at all.

Also, the 8 off outer holes are elongated / slotted in such a manner it will always fit as far as I gather.

Tightening that centre bolt seems a bad idea under any circumstances to me as its a single use TTY bolt.

It needs over 600nm to undo it let alone tighten it more.

07-17-2019, 08:54 AM	#45
doughboy Major General 1545 Rep 8,970 Posts Drives: 2018 M2 Comp 6MT Join Date: Jan 2009 Location: UK iTrader: (2)	1. Possibly, but the torque force on the centre bolt to undo is over 600nm and I can't see the hub to bolt friction exceeding that, so yes it moves the failure point to the bolt, but that seems a better option than not! If the hub moves a fraction then it will be "helped" by being held against the bolt head via the capture. So then you have hub friction + bolt friction to over come. 2. The weight of the Litchfield capture was imperceptible when placed in the palm of my hand, literally a few grams, it is obviously made of a lightweight alloy. It's centrally located at the very centre of the rotating crank, again can't see an issue with that when you have large heavy damper pulleys and flywheels hanging of the crank ends! Fingers crossed, no one US or other, has had a spun hub with a bolt capture fitted....
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07-24-2019, 06:22 AM	#47
doughboy Major General 1545 Rep 8,970 Posts Drives: 2018 M2 Comp 6MT Join Date: Jan 2009 Location: UK iTrader: (2)	Yes, Litchfield will ship capture overseas I think. Drop them a line. Main difference is theirs has a built in 17mm hex cap that completely covers the main 17mm center bolt and allows use of a 17mm spanner to turn the motor over if required at all. Also, the 8 off outer holes are elongated / slotted in such a manner it will always fit as far as I gather. Tightening that centre bolt seems a bad idea under any circumstances to me as its a single use TTY bolt. It needs over 600nm to undo it let alone tighten it more.
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