Anyone know anything about disc brakes?

You paying? Cheers!!

Do you have to change wheels? There's no QR/barrel you can use to take up cable slack?

nah, just wiggle a screwdriver between the pads and pop the fatter rotor in. jobs a good un.

Well, yes - you can do that. It's not a risk free or easy procedure however, especially if you use the wrong tool to do it.

@Turkish 's question was how to avoid doing any kind of procedure if you have variances in rotor or hub spec. The answer is to avoid those in the first place, and if that's not possible, the easiest solution with cable discs is an inline barrel adjuster.

(although I understand that some on here don't recommend tuning cables with adjusters - as in extreme doing so can affect the piston actuation mechanism - I think you can get away with it, to an extent)

@turkish could you use the cable adjusting screw on the caliper. Have the brakes set for the thickest rotors and when using thin ones adjust via cable screw.

@hippy @TheShipwright

As Howard said, using the barrel adjjuster would make the brakes feel like shit with the narrow rotors. The answer may just be new wheelset

When in doubt... buy a new bike!

#rep

@turkish I reckon the difference between rotor thickness wouldn't be enough to create a noticable difference in performance. Its's the resting position of the arm where the cable attaches that makes the difference to feel/performance and it would be easy to check. Put your thin rotors in and adjust using the cable adjuster and watch the arm whilst you're adjusting it.
I have spykes and it's only when the arm is quite a bit off the perfect angle that it seems to make a difference although maybe the spyres have less overall movement and tolerances are less?

Use the same brand of rotors on both sets. If the hubs put the rotor at different offsets, that's 2 secs with a 5mm allen key, assuming it's a postmount caliper.

Or you can shim them in to the correct position, assuming they are six bolt. And you don't need negative shims :)

I had this problem with XC race wheels on what is now Branwen's Cannondale - it was actually a real pita because the hope and old cannondale hubs put the rotors in such a different place that you couldn't even get the wheel in if you tried a direct swap. Ended up shimming the shit out of the cannondale hubs.

The calipers were direct mount IS, so no, no adjusting in five seconds there.

All these problems that I'm only hearing about after he sells me the bike!

Sounds like a case for new wheels at the least

Just don't buy new wheels

Just buy a new bike #inb4hippy

Surely shimming the rotors can only correct for a lateral offset from the hub centre rather than a difference in rotor thickness.

Use the same brand of rotors on both sets. If the hubs put the rotor at different offsets, that's 2 secs with a 5mm allen key, assuming it's a postmount caliper.

I was responding to this, and assuming we've got to the point where the rotors are the same width.

They're spyres, it's a quick job with a 3mm Allen key.

My main wheelset is centrelock, which are thinner and with a 'lower chainline' than the thick rotor 6 bolt set. Not sure centrelock shims are a good idea and I'm struggling to find negative shims for my 6 bolt hubs ;)

Seems less effort to just swap tyres over when I need them

Not sure centrelock shims are a good idea

Doesn't sound like a good idea does it? I've never tried it. Not sure I would.

@snottyotter you'd think so but the bloody things don't really work - there's nothing to 'hold' the adjustment point in place, and they seem to get re-set over time. It's the only thing about spyres that is currently garbage.

That reminds me... Got some chubby wheels to fit GF's Fatbike last summer and I should shim the rotors on whichever set of wheels has least offset.

Never seen a shim for centrelock though.

You could use a centrelock -> 6-bolt adapter and then shim that?

I'd rather buy another matching centrelock wheelset than use a 6 bolt adapter. My original post was meant to be asking if anyone knew of any narrow 6 bolt rotors

My original post was meant to be asking if anyone knew of any narrow 6 bolt rotors

What width is that? 1.7mm?

(on another note: I have shimed a center-lock rotor :) But that is probably not an example to follow...)

Not entirely sure. The difference between mine is only around 0.2mm, but enough for the thicker set to rub both pads

Great.... ahem ..but If you want people to help you maybe you should give some measurements/specifics/make so people can help you! :)

well I found this (from 2012 so everything could be wrong...)

Magura... 2.0mm Hope...1.60mm +0.05mm Hayes ...1.75mm to 1.78mm thick Shimano 1.8mm thick

http://www.velonews.com/2011/10/mtb/tech-faq-lennard-zinn-on-rotors-and-drilling-frame-drain-holes_252053

I have no way of accurately measuring them, so not sure what else I have to offer. Theyre both shimano though, even though that link says all Shimano rotors are 1.8. Neither set of rotor are old enough for wear to make a difference

I have a set of shimano 6 bolts on a stock Giant wheelset and a set of centrelock rotors on Dt dwiss 250s. Both Ice-tech and they don't need more than a couple of clicks on the pad adjustment on my Spyres when I swap between wheels. I've never had any problem with the adjustment screws loosening, mine definitely have a 'click'.