figbat
Slippery scientist
- Location
- South Oxfordshire, UK
The disc does look very thin. But also it looks like the pads were tracking ‘low’ on the disc. Some calipers have a washer arrangement for alignment; could be missing?
Failed Disc
- Thread starter Marchrider
- Start date
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Drago
Legendary Member
- Location
- Suburban Poshshire
This is it in a sentence. He couldn't be arsed to do his pre ride checks, but strangely can be arsed to blame anything but his own carelessness and negligence.
Ming the Merciless
There is no mercy
- Location
- Inside my skull
Despite many thousands of miles on many bikes over many years, I've only ever had one rim wear though.
Got to love anecdotes 🤣😂
OP
OP
Marchrider
Über Member
No, and I made that clear on the first page, I know nothing about disc brakes on bikes - simply exploring what might of happened, I only have that rather poor image to go on + a few measurements that will have been done accurately
pretty much siding with those who are saying it would be the correct size disc and probably failure due to thinning -
bit weird the way some of you are going on
Who is blaming who ? my brother ain't blaming anyone, I haven't blamed anyone !
why ?
Drago
Legendary Member
- Location
- Suburban Poshshire
Oh, OK. He accepts it was his fault then. My apologies.
OP
OP
Marchrider
Über Member
that has never been said either - stop making stuff up - you will be telling us how big you are shortly
as far as I gather from my brother he's a bit disappointing he won't have his bike for a few days
Alex321
Guru
- Location
- South Wales
Scale.
As has been repeatedly suggested it's highly unlikely that any brake system would physically allow a 180mm disc to be fitted in place of a 160mm item without an adaptor to space the caliper out.
If there's a pad / disc alignment issue present in the image in the OP, it's in the order of 1-2mm not 10 - this would leave half the contact surface of the disc unswept.
Seeing exactly by how much the contact area of the pad would move on the disk were it 20mm smaller in diameter (by using a ruler for reference, for example) might help illustrate this...
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fossyant
Ride It Like You Stole It!
- Location
- South Manchester
A 6 and an 8 can look similar if stamped on a disc. It's one or the other and running a 180 20mm spacer if 180 otherwise it won't fit ever, but we don't have pictures of the disk
We're on four pages and op was told it was a worn out disk on page one. But wouldn't accept it.
You can get next day delivery from amazon for a disk. Get a clarkes if not sure.
We're on four pages and op was told it was a worn out disk on page one. But wouldn't accept it.
You can get next day delivery from amazon for a disk. Get a clarkes if not sure.
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OP
OP
Marchrider
Über Member
if you had read the first page you would have noted the bike is not mine and is a 1000 mile away in another country, and on that first page the thougth was raised it could be a disc size issue, i wanted to explore that possibility further
You could always put a thread on ignore if it gets onto page two. I do small engineering projects all the time, hence my interest - I probably like to explore things more deeply than many others do (ridiculously so sometimes). I like to be certain and get it right - just because one caliper has a close tolerance,that all calipers do, then some people just make things fit with a big hammer if necessary - I know someone who continually jams ¼" spindles into a 6mm collet, ruins them.
and yes 6's and 8's can be confused esp on old parts where they are worn away - have this issue all the time esp with well used taps & dies, and my ageing eyes
Getting back to the disc, I'm thinking it probably is 180, discs are often bigger on the front than the rear (or at least they are on cars and lorries) because they handle more braking force due to weight transfer - the same will be true of bikes - 180 front 160 rear could be the case, as an earlier poster pointed out.
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Regular.Cyclist
Über Member
- Location
- South West Scotland 🏴
My road bike has the same sized disc front and rear as does my wife’s. Only our mountain bikes have a larger disc on the front. I appreciate it’s a small sample size though and bikes / brands may vary.
Looking at all four disc bikes we have the calliper would make it impossible to refit the wheel with a disc 20mm oversized.
craigwend
Grimpeur des terrains plats
Intersting to see how the thread has developed at times like a game of Chinese whisper...
Photo makes it pretty much impossible to know what has actually happened. My best guess is disc has worn far too much, like others not sure if you can put the wrong size in most standard brakes without adjustment?
Unscientific poll. My road bike has same size discs, at my daughters her housemates bike has a larger front than back.
Side point from what we can see the wheel / spokes look quite old generally and looks like quick release rather than through axle?
@Marchrider Glad brother is okay, please request more photos for more enthralling debate and conjecture
Photo makes it pretty much impossible to know what has actually happened. My best guess is disc has worn far too much, like others not sure if you can put the wrong size in most standard brakes without adjustment?
Unscientific poll. My road bike has same size discs, at my daughters her housemates bike has a larger front than back.
Side point from what we can see the wheel / spokes look quite old generally and looks like quick release rather than through axle?
@Marchrider Glad brother is okay, please request more photos for more enthralling debate and conjecture
Yellow Saddle
Guru
- Location
- Loch side.
That's a tenuous argument. Stamped text on the non-swept section does not wear away. Further, just because you can have a bigger disc in front doesn't mean there was a bigger disc in front. It could have been 180/160 - 160/160, 160/140 or even 140/140.
180s are usually found on performance bikes only, unless there has been some fiddling with the brakes afterwards.
Dogtrousers
Kilometre nibbler
This and other recent threads make me relieved that I bought my bike before discs became mainstream.
Discs may well have their advantages but they seem to come with a whole world of mystique and complication that you just don't get with rim brakes. I just don't think I'd be clever enough for discs.
Discs may well have their advantages but they seem to come with a whole world of mystique and complication that you just don't get with rim brakes. I just don't think I'd be clever enough for discs.
rualexander
Legendary Member
It's only "mystique and complication" if you're not familiar with them.
They are no more complicated than rim brakes, just different.
