Chain guard sheared off of chain ring + a few other things

TS25

Well-Known Member
Region
Europe
And the beat goes on.....sheesh
I asked:

Zach,
Thanks for the reply, however, the most important part of the question has yet to be answered.
The length of the screw!
I have measured the bolts, they are 8MM, I can only find 7MM.


He replied:
I really apologize for omitting that, 6mm length.
Zach | Specialized USA Rider Care

C'mon, terrier,
tug on Zach's pant leg one more time, and you're almost there.

Just measured my old Specialized chainringbolts precisely (see pics) :
8,81 mm total length (total always includes the bolt head) ,
should be 7,5 mm nominal bolt length.

6mm? Never.
 

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Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
Just measured my old Specialized chainringbolts precisely (see pics) :
8,81 mm total length (total always includes the bolt head) ,
should be 7,5 mm nominal bolt length.
I measured the RocRide bolts that I mentioned earlier. The total length is 10.44 mm. However, the excess length of the thread comes outside of the nut and the total length of the working part of the bolt comes down to 8 mm. Meaning: Using the bolt together with the nut is OK.
 

TS25

Well-Known Member
Region
Europe
I measured the RocRide bolts that I mentioned earlier. Total length of the working part of the bolt comes down to 8 mm.
So your bolts are M8x8mm nominal size?
Perfect even for the Specialized chainring if you apply some grease (because they are steel).

You've done well to buy plenty so now you could sell some to GuruUno. And remember they are rare, if you put the price tag on 😅.
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
You've done well to buy plenty so now you could sell some to GuruUno. And remember they are rare, if you put the price tag on 😅.
Haha! Hadn't he lived overseas, I could even make a gift to him! (Actually, I sent some gear to an EBR Forum friend overseas but he paid expensive shipment) :)
 

GuruUno

Well-Known Member
OK, got 2 brand spanking new chainguards/bash guards ( 1 for a spare, just in case), and I put it on today.
After 10 miles, pop, it sheared off again.
No road obstructions, no irregularities of any condition of the pavement, just plain, smooth asphalt roads, and pop.
I can only make an assumption that the new chain is either wider than the OEM chain (I put on a Shimano STEPS CN-E8000 11-Speed E-Bike Chain), or the Praxis OEM chainring is different (it's identical to my eyes).
This is the chain I bought: https://www.rei.com/product/182354/shimano-steps-cn-e8000-11-speed-e-bike-chain

This is the chainring guard I bought: https://www.amaincycling.com/specia...lastic-bashguard-black-48t-s179900050/p750218

This is the chainring I bought: https://www.amaincycling.com/specia...4mm-bcd-wave-48t-s171400002/p1276153?v=750196

The ONLY other thing MAYBE which MIGHT be a contributing factor (and I'll verify as I have 1 additional, spare bash guard, as I said I bought 2), is that the 4 mini-screws that hold the guard on....I put a 'drop' of blue thread lock on each screw, both times. Maybe it expands the plastic and it swells and breaks off? I'll take my 3rd one and use nothing, as it was OEM, and we shall see.

If not, opinions, comments are always appreciated.
 

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TS25

Well-Known Member
Region
Europe
I can only make an assumption that the new chain is either wider than the OEM chain (I put on a Shimano STEPS CN-E8000 11-Speed E-Bike Chain), or the Praxis OEM chainring is different (it's identical to my eyes).

The ONLY other thing MAYBE which MIGHT be a contributing factor (and I'll verify as I have 1 additional, spare bash guard, as I said I bought 2), is that the 4 mini-screws that hold the guard on....I put a 'drop' of blue thread lock on each screw, both times.

11-speed-chain is 11-speed-chain and their width is norm. Can't be the reason.

But Loctite thread lock is for metal to metal screw connections, and Loctite blue isn't the right Loctite for small screws, too (thats purple or 222 Loctite).
 

GuruUno

Well-Known Member
So, in conclusion, I will add that I found this. I did not know. Hopefully, then the case is closed.
'During a preventive maintenance check of an anesthesia ventilator, a member hospital found that a low-pressure alarm malfunctioned because of a broken pressure switch.
The manufacturer of the ventilator and alarms investigated the problem and found that it was caused by Loctite, which had been applied to the pressure-setting screws of the pressure switches. The Loctite, which had been used to hold screw settings, caused the polysulfone plastic body parts of the switches to deteriorate and crack, releasing the pressure-compensating spring under the set screw and causing the switches to fly apart. The manufacturer's experience has been that the screws hold their settings without Loctite.'

For many years I always thought Loctite was Loctite, did not know multiple versions for different applications existed.
Whew.....