How long do disc rotors last?

[Brucey]

FWIW cheap brake discs are liable not to be of perfectly uniform thickness, or to be properly stress-relieved (heat treated) during manufacture, so are perhaps more likely to warp in use. Good brake discs (like Hope ones) cost a bit more for a reason.

For me, the cost argument is a valid one. Although there are lots of folk who have never tried it, it isn't difficult to re-rim a wheel; if you can change a spoke and get the wheel true again, you can almost certainly re-rim a wheel, too.

Note also that a good portion of both rims and discs don't get a chance to wear out; they get pranged/bent instead. FWIW I'd rather true a slightly wonky wheel than true a slightly wonky disc; I'm far more likely to get an acceptable result with the wheel.

cheers

[cycle tramp]

At this point I will be slightly annoying by typing the words 'hub brakes' into a message before posting it... ....You knew someone was going to.....

[peasantpigcyclist]

Disc truing is much easier than wheel truing. In an emergency, use a lobster claw type adjustable spanner. You have to over bend the disc as they are quite springy!
Discs can last a long time.
Depends on brake pad material and what becomes imbedded in them,just like rubber brake blocks on rim brakes. Grit can turn them into an abrasive material, add water during rain,puddles etc and the pads and blocks become like wet and dry paper!
Generally , commuter cycles will wear out components faster than leisure, touring and racing on the road.
This is due to constantly acceleration and braking onto a stop start journey. Racing, touring and leisure tends to have longer periods of riding inbetween braking applications.

[foxyrider]

My experience is that the discs cost me more to keep in good order than rim brakes. My bike with discs is used largely in quite hilly terrain but that doesn't seem to be an issue as I wore out a set of pads during a three week tour of Holland/Denmark/Germany where the biggest drop was getting off the ferry!

That said it's on the second set of rotors and they are quite worn so will need changing soon. We are talking quite obvious pad track grooves and burning (even on the front 180!) I also seem to go through an endless number of pads, best wear with organic, best braking with sintered, i've tried all sorts of brands and Shimano seem to be as good as any.

Over a similar mileage/terrain/use time i'm just coming up replace rim pads for the first time on the other bike with negligible rim wear. We're looking at @ 5000km each bike over 2 years. (I have other bikes too but that's beside the point!) Cost of keeping the discs working for 2 years @ £80 so far, rim brakes - well nothing yet but will be @ £40 if I fit Swiss Stop!

[Cyril Haearn]

Changed a pair of BB5 rotors that had done approx 12,000 miles on the daily commute bike. They still worked fine but did have noticeable wear on them.

Do you ride fixed, fixedfixer?
My fixie has rim brakes that are *never* used

[mattsccm]

Surely its too situation specific to be answered . I got through a rim every 5000 miles (ish) on gravel with rim brakes. About 18 months at the most. Swapped to discs in 2010 and haven't fitted a new disc. 2 or 3 sets of pads a year compared with no more than 2 pairs of blocks. Others will differ.

[gloomyandy]

I have 5000+ miles on my touring/winter bike, no real sign of wear on the cheap but fine lifeline discs. One new set of pads, original TRP ones lasted about 2000 miles the clarkes sintered ones I replaced them with are still going strong. Most of that riding has been either in NW Scotland or in the hilly parts of W. Yorkshire, but not commuting. The disc pads cost less than the brake pads I would normally use on my rim braked bikes, the discs cost £5 each. So for me I'd say that discs are probably lower cost to run. I've never had any issues with discs going out of true on this or my previous touring bike (which also had discs), I wonder sometimes what people do to them!

[freeflow]

With rims costing about the same as rotors, could there be little difference in the respective running costs.

That's not correct. You also need to include the cost of the time to install the new items. For disk rotors maybe 15 minutes. For rims possibly a couple of hours at least.

[simonhill]

Thanks for the replies, particularly those that tried to answer my obviously woefully phrased question.

I realise that replacing a rim is a bigger job than replacing a rotor and thank the many people who pointed it out, seemingly oblivious to the fact that it had already been made (and made).

The cost isn't a deal breaker for me. Given the bikes I have and my age I am unlikely to be changing soon, if ever. It was that the 'rims wear out' mantra seems to oft be heard, whereas rotor replacement is rarely cited. But now I know and thanks for that.

As to my time and cost - I believe in fit and forget. My LBS fits and I forget.

[Gattonero]

How long do disc rotors last?

OK, a bit of a piece of string question, but I wonder how often, with any given sort of use, they need to be replaced.

I do have an ulterior motive. It is often said that rim brakes wear our rims, which they do. But you rarely hear people criticising disc brakes for wearing out rotors.

With rims costing about the same as rotors, could there be little difference in the respective running costs.

My last Rigida Sputnik rear rim lasted over 40,000 kms when replaced with wear line showing. Front is still OK, a further 5,000 on. Mainly touring and day rides - but I do try to avoid the wet.

Yes but replcving rotors only requires a T25 wrench or a Shimano HG cassette tool and can be done by anyone in 2 minutes.
So the parts may cost some money, but the saving in labour cost, and time involved, is substantial.

[Brucey]

they chuck out dozens of used discs in LBSs near me. A good number are worn, a similar number are bent, some manifest thickness variations (which can make a disc that measures straight judder very badly), and some are more or less OK but don't match the new brake caliper.

A typical happenstance is that a (more often hydraulic than not) brake caliper fails, and is replaced with something different. The brake track/pad width doesn't have to be very different or very worn before a new disc is a good idea too. On some bikes the factory brake install is not very good, in that the brake pads don't run on the brake disc's brake track properly, presumably because the disc mounts are not accurately made. This can cause discs to wear prematurely too.

Brake discs are not always easy to change; very often the torx-headed bolts round out because they are seized, and the heads need to be ground off. Hubs that are built light, in which the disc mounting bolt threads are open at the rear of the mount, seem worse for seizure than hubs in which the threads are covered, [think of the difference between FH-M756 and FH-M525, for example.] Needless to say if the bolts are fitted with anti-seize to start with, this sort of thing is made very much less likely.

cheers

[Gattonero]

I'd say it's more likely to find seized/damaged spokes than seized disk rotor bolts.

[elPedro666]

My experience has been that I notice considerably less wear to discs (currently spanning £2 eBay Avids to XTR RT97 centrelock) than to rims in the same generally filthy, Peak District conditions. Rim pads can vanish in a single ride too, whereas disc pads of various brands and flavours all seem to do considerably better.

For me though the biggest bonus of discs is the lack of that hideous black paste which rim brakes create by the gallon!

Those £2 Avid discs are spot on too, in case anyone was wondering about them, but I love the simplicity and security of centrelocks.

I'm a trendy consumer. Just look at my wobbly using hovercraft full of eels.

[Tigerbiten]

I find that rotor life is roughly based on how badly I overheat them on a silly fast downhill run when I'm pulling a full camping load.
Once they get heat warped then they're never the same.

Also calipers are the never same once I've melted any plastic bits (BB7's) on cable brakes or blown a seal on hydraulic brakes.
I've done both ..........

[[XAP]Bob]

Current set are 6 years of commuting old - easily 12k, and no sign of needing replacing any time soon.

I’ll take a proper look at some point, but I do like hard braking