Flanged nuts

[gizmo]

Flanged nuts a good idea on side casing? Wondering if they have more chance of vibrating loose with no spring washer. Do come in nyloc version but nylocs are a divided opinion I know on side casing

[Fast n Furious]

I've never had a problem when using M6 nyloc flanged nuts with flat washers behind.
When they have been on and off a few times the nyloc does lose some of its effectiveness but that's normal for nyloc applications.

[LambrettaMarky]

I'd use Nyloc when possible & generally replace after it's been on/off a couple of times.

[gizmo]

I've never had a problem when using M6 nyloc flanged nuts with flat washers behind.
When they have been on and off a few times the nyloc does lose some of its effectiveness but that's normal for nyloc applications.

. You would still use washers with a flanged nut then

[Storkfoot]

I have MB flanged nuts on one scooter. They never fell off but, if you just touch them with a socket, they come loose very easily. I put wavy washers underneath and they are fine now.

In my experience, nylons are a pain. Unsurprisingly, the original design of deep nut with a washer are the best.

The flanged nuts which have a serrated bottom are great for bodywork. No need to fiddle with washers when putting on your runner boards for example and I have never had one come loose.

[Fast n Furious]

I've never had a problem when using M6 nyloc flanged nuts with flat washers behind.
When they have been on and off a few times the nyloc does lose some of its effectiveness but that's normal for nyloc applications.

. You would still use washers with a flanged nut then

The purpose of the flat washer is to prevent the grinding effect from the face of the nut on the face of the casings which happens as the nut gains tensile compression. Serrated faced nuts are designed to work without washers. The serrations bite into the ally to create a lock but they also have a grinding effect every time they are tighened and slackened, which isn't a problem for soft ally applications that rarely, if ever, get dismantled. Just not the best approch here.
M6 x 14mm x 1.2mm thin washers work just fine, especially it your studs are only just long enough for the nylon ring of the nut to grab the end of the stud. + Non serrated faced, M6 flanged, stainless nyloc nuts.
Alternatively, you could consider using M6 stainless dome headed Nyloc nuts with M6 x 10mm washers. I actually use M6 Dowty washers here, which offer an extra seal should oil try to leak out past the stud. (My preference)
If the chaincase gasket is new, then it's best to recheck the tightness of the chaincasing nuts after 100miles. The gasket does thin out a little after it has been under compression and soaked in hot oil for while. This is normal. So, recheck and torque down to 3.5-4.0 ft/lb

[gizmo]

I've never had a problem when using M6 nyloc flanged nuts with flat washers behind.
When they have been on and off a few times the nyloc does lose some of its effectiveness but that's normal for nyloc applications.

. You would still use washers with a flanged nut then

The purpose of the flat washer is to prevent the grinding effect from the face of the nut on the face of the casings which happens as the nut gains tensile compression. Serrated faced nuts are designed to work without washers. The serrations bite into the ally to create a lock but they also have a grinding effect every time they are tighened and slackened, which isn't a problem for soft ally applications that rarely, if ever, get dismantled. Just not the best approch here.
M6 x 14mm x 1.2mm thin washers work just fine, especially it your studs are only just long enough for the nylon ring of the nut to grab the end of the stud. + Non serrated faced, M6 flanged, stainless nyloc nuts.
Alternatively, you could consider using M6 stainless dome headed Nyloc nuts with M6 x 10mm washers. I actually use M6 Dowty washers here, which offer an extra seal should oil try to leak out past the stud. (My preference)
If the chaincase gasket is new, then it's best to recheck the tightness of the chaincasing nuts after 100miles. The gasket does thin out a little after it has been under compression and soaked in hot oil for while. This is normal. So, recheck and torque down to 3.5-4.0 ft/lb

. Thank you