Anyone know anything about disc brakes?

Shimano describes them as 140mm rotor compatible

Wheel compatability is minimum rotor size, the spokes will clear the specified calipers with a rotor that size. Bigger rotors will only open up that clearance.

Brilliant, thanks. That makes sense. I'm not ashamed to admit I was struggling with Shimano's definition of "compatible" here.

I have a Surly Straggler that I bought frame only. I transplanted a SRAM Rival 1x hydro disc groupset from a Canyon onto the Surly.

The brakes for this group are shit and have always been shit. The Straggler is currently set up with drop bars but is mostly ridden as a town/pub/dad bike and so I'd like to put a flat bar on it, if it was possible to do this fairly cheaply. Any suggestions on how this could possibly be done?

many thanks

1. Buy 11 speed flat bar road shifter (e.g. Apex)
   
2. Buy flat bar brakes
   
3. Install
   
4. Sell old shifters and brakes for a net profit
   
   

Done

Don't buy any 11 speed mountain bike components

Nice one, I thought this was the way to do it but didn't know it was an option because I'd read that the flat bar shifters used a different actuation type than the dropbar/road shifters. But your suggestion makes sense. Any recommendation for compatible flat bar brake and/or rad handlebar would be great too. Thanks again!

Yeah, the flat bar mountain bike shifters are incompatible but the 11 speed Apex should work fine. Actually it might be the only option as I can't see any Rival/Force version. (You need SRAM Exact Actuation 11 speed, and any 1:1 Actuation or X Actuation will not work.)

Anyone managed to buy replacement GRX pads recently? L03A or similar? Ta.

I guess they're different to Ultegra etc but I always buy the ones without the fins now. If you look for those they're cheaper and more common.

I've got squealing brakes - plan is to remove pads, clean rotor with scourer and dish soap and install new pads. Anything else (other than buying a new bike) I should bother doing?

I tried cleaning the rotors already and this didn't help and I filed the pads and that didn't help either so it could be deeper issue and need rotor swap.

They're the same pads but hard to come by Shimano branded ones, other places aren't as completely rinsed as they used to be though. I doubt you'll be finding Shimano L anything (finned) for a little while.

I currently have a set of cable operated cx77 calipers paired with r7000 shifters on my bike.

Looking to upgrade to hydraulic, is a set of r7020 shifters and r7070 calipers the best way to go, or are there alternatives.

I've attached images of the caliper mounts. Will this work ok with r7070 flatmounts?

2 Attachments

I bought LO4C to replace worn LO3A at Sigma last week

Will this work ok with r7070 flatmounts?

Nah. You need post mount on the front and back with IS to post adapter on the back

That's post mount front and IS rear, so best bet would be post mount brakes and an IS rear adapter, deore MTB brakes work fine with those levers, the SLX and above will also work but you'd need to get hoses with a banjo for the caliper, so less of a straight swap.

There are various remedies like filing a leading edge on the pad like you used to on rim brakes (well, were supposed to but I never did) or to put grease on the back of the pad but I just find that some pads screech and some don't.

It's the luck of the draw.

I just sand-papered and isopropyl'd the fuck out of rotors and pads. It made a difference for sure but the back is still a bit squealy and braking feels meh after another bed-in.
It's only a 140mm rotor so I wonder if I could stick a 160mm on. I presume I could find an adapter to move the XTR caliper outwards.

I wouldn't be cleaning rotors and pads with soap, that could be the residual contaminant causing your squealing. Clean with alcohol.

I'd assume you'd be running 203 on everything with all that inertia.

Clean with alcohol

You can't drink soap though

Hand sanitizer? It's basically soap and alcohol in one.

I've cleaned my road bike rotors like this for years and they're great afterwards, These are MTB pads/rotors on the GrInbred. Must be a bit more 'baked in' shit. Also, I've no idea what the pads are - the back one looks green. Front I think is Shimano.

I run 160/160 on the road bike.

Never swapped rotors on my MTBs. I think I've spare 6-bolt 140mm but nothing bigger. #hippyisfat

If it's still squealing after cleaning and putting fresh pads in, check your caliper is properly aligned, then balance the pistons so they contact at the same time by holding back the more advanced pad while advancing the other

I didn't bother with the fresh pads yet. This scrub shut them up more than before so I'll see how that goes longer term. I'm not riding it much so I don't really get to test it out properly. Rear could probably do with a re-centre though, good point.

@snottyotter @frankenbike

Thank you both, saved me a lot of faffing about.