Regular.Cyclist
Über Member
- Location
- South West Scotland 🏴
There looks to be wear across the whole of the outer part of the disc and it appears to have worn paper thin. 10mm is huge and should have been obvious.
Failed Disc
- Thread starter Marchrider
- Start date
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There looks to be wear across the whole of the outer part of the disc and it appears to have worn paper thin. 10mm is huge and should have been obvious.
OP
OP
Marchrider
Über Member
come on, you need o back that up - it could have been a chicken crumble
no, seriously how else would you explain the failure ? the pads have missed to edge of the disc and caught on the legs
do you think he has CGI'd the whole image - now I wouldn't put that skill past him
Regular.Cyclist
Über Member
- Location
- South West Scotland 🏴
The pads haven't missed the disk by 10mm though.
fossyant
Ride It Like You Stole It!
- Location
- South Manchester
It's worn too thin, that's how it's failed.
OP
OP
Marchrider
Über Member
the spec for the bike is 160mm
the fitted disc is 180mm
and the inside radius of the pad has fouled the supporting arms of the disc
the fitted disc is 180mm
and the inside radius of the pad has fouled the supporting arms of the disc
Regular.Cyclist
Über Member
- Location
- South West Scotland 🏴
It’s simply worn too thin. That’s not a disc that is out by a radius on 10mm.
fossyant
Ride It Like You Stole It!
- Location
- South Manchester
Exactly. A 180mm disc won't clear the caliper if fitted for 160mm. It's clearly paper thin.
OP
OP
Marchrider
Über Member
what clearance would you expect from the outer edge of a disc to the well of a caliper ? and how much adjustedment does a cliper have in aligning to a disc
it clearly isn't paper thin, 1.1 to 1.3mm, and do bicycle pads normally foul the supporting arms?
it is without doubt a 180mm disc and the bike spec is 160mm - that 10mm smaller radius I expect will give a better fit
it clearly isn't paper thin, 1.1 to 1.3mm, and do bicycle pads normally foul the supporting arms?
it is without doubt a 180mm disc and the bike spec is 160mm - that 10mm smaller radius I expect will give a better fit
Despite many thousands of miles on many bikes over many years, I've only ever had one rim wear though.
chriswoody
Legendary Member
- Location
- Northern Germany
just going by my two bikes, theres not a lot of room between the caliper and the disc. The Green mountain bike has stock SRAM calipers which are 3mm from the disc, the Hope calipers on the Gravel bike sit only 1 mm from the disc.
When I upgraded the front brake on the gravel bike from 160 to 180mm I needed a much larger, brand new adapter to make it work, there was no way you could bung a bunch of washers under the bolt to make it function.
When I upgraded the front brake on the gravel bike from 160 to 180mm I needed a much larger, brand new adapter to make it work, there was no way you could bung a bunch of washers under the bolt to make it function.
Regular.Cyclist
Über Member
- Location
- South West Scotland 🏴
Only a few mm at best. Nowhere near 10mm
Yellow Saddle
Guru
- Location
- Loch side.
No, they didn't catch on the legs. Those are still the original diameter and the thinning starts where the legs enter the friction surface. A cut-through would look like a profile cross section of a pipe reducer.
fossyant
Ride It Like You Stole It!
- Location
- South Manchester
There is less than 5mm clearance on my callipers so you aren't getting an out of spec rotor in there. Bike spec basic will be 160mm, but will have a spacer for the calliper which allows different sizes.
Those discs are way too thin thats why they failed. Bent like kitchen foil.
PS OP, do you actually have a bike with discs ? Your brother has failed to check wear - don't go blaming something else.
These are the discs that I took off the MTB a couple of weeks ago - they are 180(F) and 160(R). Note the position of the wear from the pads that overlaps the support arms is similar to that shown by the OP. I carelessly let these get significantly below the recommended thickness but was fortunate in that they didn't fail.
