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I am looking to increase my rear rotor from 160mm to 180mm I understand I'll need to get an adapter for the caliper but I have no idea what to get any help would be appreciated
I'm hoping that link will show the mount I have at present.
Dave
A 180 rear IS/PM
https://bike.shimano.com/en-EU/product/service-upgradeparts/shimano/ISMMAR180PSA.html
I don't think those conical washers are supposed to go underneath the caliper with that set up. I'm sure someone else more knowledgeable will come along who knows more.
normally the washers go above to allow bolt to enter at a non perpendicular angle, those above are effectively being used as a spacer
Looking at that, and squinting, i'm pretty sure the pads aren't getting full contact with the disc.
Though it also looks like the IS mount holes are slotted. So who knows.
You might get the power you want just by removing those incorrect washers and allowing the pads to push against the whole of the vraking surface of the existing disc rotor.
Removing the washers will REDUCE the braking torque as you are reducing the radius at which the braking force is acting. Even if the pads aren't in full contact with the disc.
Increasing the radius is the only reason a bigger disc increases braking torque :o)
It's possible that any current lack of stopping power could be due to the pad faces only half meeting the rotor braking surface. As they've worn, you might find that looking into the caliper from the top, you'll see pad touching pad with no rotor in-between
Those conical washers... I'm obviously doing something wrong as I put them straight in the bin, personally.
Will I die?
Phew @rickmeister, thought it was just me...
@JAG I'm not sure that's true. It'll still be acting on the outer portion of the disc, but there won't be as much surface area to n create friction, surely?
Friction is independant of surface area - so...
Effective radius is the best way to manage brake torque output. Removing the washers, so reducing operating radius, will reduce brake torque. Only a little bit (directly poportional to the reduction in the radius) but strictly speaking it will be lower :o)
UNLESS @onzadog is right and the pads have worn enough to now be touching each other when the OP squeezes the brake lever ;o)
Will I die?
Possibly.
Without the washers and depending on the frame and spacers, you may be introducing a bend to the bolt.
Which may, eventually, lead to the bolt snapping.
Looking at that, and squinting, i’m pretty sure the pads aren’t getting full contact with the disc.<br />Though it also looks like the IS mount holes are slotted. So who knows.
Well spotted. Those two silver washers should be below the black washer so the calliper is sitting too high ergo the pads are not making full contact with the disc.
None of that will matter though when the OP has a 180 rotor and a 180 IS/PM mount though. As long as he/she doesn't put the washers back in there....
Thanks folks I have a new disc and caliper adapter just waiting on the pads and it'll all get changed. I'm not looking for more power mainly as I'm heavy hopefully the bigger disc will stay cooler and be more efficient as I lose weight it won't be much of an issue.
Dave