I snapped my rear 6 bolt rotor clean off whilst riding. Damn!!!!!

Binhill1

🍊 Tango Man 🍊
Mar 7, 2019
3,250
5,033
Scotland
I do check bolts every few months never had one come loose . Ebike is first time i have used any threadlock on anything or used a torque wrench . Only thing i ever remember loosening was a peddle.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,567
5,058
Weymouth
I do check bolts every few months never had one come loose . Ebike is first time i have used any threadlock on anything or used a torque wrench . Only thing i ever remember loosening was a peddle.
Peddle?..............you reduced your prices??:p
 

folmonty

Active member
Mar 11, 2021
152
156
NorCal
While it might seem impossible for this to happen most eMTB's are twice the weight of analog bikes and they often need to stop at higher speeds. Braking force is all about heat (btu's) at the pads and rotor. Those rotor bolts can take tremendous abuse from those of you "go fast" riders from significant heat cycles. Suppose it could happen to anyone. Not a lot of metal in eMTB rotors to absorb that heat. The stress downhill riders put on has to be insane! Glad you didn't have an accident @Neeko DeVinchi
 

Planemo

E*POWAH Elite
Mar 12, 2021
605
706
Essex UK
I don't think the sheer strength of 6x 5mm high tensile (which would should be using - 8.8 spec) steel bolts should be a problem on our bikes, electrified and heavy or not. The best I can come up with for the above spec bolt is a sheer strength of 5.45kN which with my back of a fag packet calculations makes around 500Kg of force if torqued up correctly. Multiply by 6 and thats a fair bit. I would suggest that an alloy hub should fail before 6 bolts sheer.

In short, I believe the hub was shit or the bolts were shit, or a combination of both being shit. Either way, IMO we shouldn't be concerned with a 6 bolt format on our discs even with heavier ebikes.
 

Binhill1

🍊 Tango Man 🍊
Mar 7, 2019
3,250
5,033
Scotland
I don't think the sheer strength of 6x 5mm high tensile (which would should be using - 8.8 spec) steel bolts should be a problem on our bikes, electrified and heavy or not. The best I can come up with for the above spec bolt is a sheer strength of 5.45kN which with my back of a fag packet calculations makes around 500Kg of force if torqued up correctly. Multiply by 6 and thats a fair bit. I would suggest that an alloy hub should fail before 6 bolts sheer.

In short, I believe the hub was shit or the bolts were shit, or a combination of both being shit. Either way, IMO we shouldn't be concerned with a 6 bolt format on our discs even with heavier ebikes.
Seen bolts sheer before when tightening them too much but 6 at once pretty dramatic . Are there any photos yet.
 

Neeko DeVinchi

E*POWAH Elite World Champion
Dec 31, 2020
1,033
1,376
UK
No need to close the thread and sincere apologies for the delay.

So, the wheel itself has been deemed 'warranty replaceable' Halfords wording, not mine.

As a result, I asked them to take a pic and send it me via WhatsApp which they have cunningly took a picture from the drive side, thereby hiding the none drive side rotor area.

Screenshot_20211121-163734_Gallery.jpg
Nevertheless, hopefully, the above picture will answer some of your questions (kind of!!!).

I'll be honest with all of you, I picked this wheel up from my local Halfords a couple of months back for cheap.... so I've learned my lesson. Not saying that halfords sells cheap things but 'you get what you pay for in terms of quality & longevity.

I'm curious as to what wheel they'll provide me being as this particular wheel is discontinued.

Again, sincere apologies for the delay and most importantly a lack of a good picture. IMG-20210118-WA0012.jpg
 

Stihldog

Handheld Power Tool
Subscriber
Jun 10, 2020
3,567
5,027
Coquitlam, BC
Glad you got the issue Resolved. It helps if you become a squeaky wheel. 😳

Replacing your wheel/hub/rotor is probably cheaper than a recall since this design has been used by many for a long time.
 

Manc44

Member
Jun 22, 2021
120
39
Manchester
BTW, did you rotate the disc clockwise a bit to remove residual play before tightening the screws? If not, a bit of slippage could lead to a sharp shear force and cut the screws.

Clockwise would create a gap to the bolts and create play. Anti-clockwise would close any gap. When brake pads grab the rotor, they pull the rotor anti-clockwise. Sorry I'm not trying to be a pedantic wanker. :giggle:

EDIT: Sorry I got it wrong.
 
Last edited:

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
14,028
20,817
Brittany, France
Clockwise would create a gap to the bolts and create play. Anti-clockwise would close any gap. When brake pads grab the rotor, they pull the rotor anti-clockwise. Sorry I'm not trying to be a pedantic wanker. :giggle:
Wouldn't you want clockwise ? The wheel would be turning anti clockwise when you ride - when viewed from the disk side. So when you brake, it would be trying to stop the disk and applying the equivalent force to turning it clockwise ? Unless you have a digital watch of course, or ride in Australia.
 

Manc44

Member
Jun 22, 2021
120
39
Manchester
Yes a wheel goes anti-clockwise from the disc side, but when the rotor is pulled by the pads, they are pulling it clockwise. Roll a coin from right to left and put pressure on it at 3 O Clock like a brake, then more pressure... until it's so much you're pulling it in reverse - any rotor is being pulled clockwise.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,567
5,058
Weymouth
Yes a wheel goes anti-clockwise from the disc side, but when the rotor is pulled by the pads, they are pulling it clockwise. Roll a coin from right to left and put pressure on it at 3 O Clock like a brake, then more pressure... until it's so much you're pulling it in reverse - any rotor is being pulled clockwise.
ie the opposite o what you said before:p
 

Planemo

E*POWAH Elite
Mar 12, 2021
605
706
Essex UK
So we still don't know what happened then.

I wouldn't expect any branded wheel to fall apart at the disc mounting area, 'cheap' Boardman or not, so we remain confused without more pics/info.
 

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