Are rotors important?

[silk186]

no "Select Option Pair - Right Hand Front/Left Hand Rear"

 

[silk186]

the rotors I'm not asking about the brakes

 

[I like Skol]

Hey Silk. I am still running the original Tektro (crap IMO) rotors on my hybrid commuter and have covered over 10,000 miles on them in all weathers. I did skip the original Tektro brakes after 2000 miles due to them being utter junk and replaced with Shimano XT which have performed almost unnoticed for the following 8k apart from the odd pad change. The brakes are reliable and powerful even with the original Tektro rotors so I would suggest keeping the rotors if they are straight and not very worn and just clean them up before fitting new brakes

 

[silk186]

Hey Silk. I am still running the original Tektro (crap IMO) rotors on my hybrid commuter and have covered over 10,000 miles on them in all weathers. I did skip the original Tektro brakes after 2000 miles due to them being utter junk and replaced with Shimano XT which have performed almost unnoticed for the following 8k apart from the odd pad change. The brakes are reliable and powerful even with the original Tektro rotors so I would suggest keeping the rotors if they are straight and not very worn and just clean them up before fitting new brakes

Thanks, that's what I wanted to know. Do you know if their is a noticeable difference between different rotor sizes?

 

[Panter]

Thanks, that's what I wanted to know. Do you know if their is a noticeable difference between different rotor sizes?

Yes, there is. 185mm rotors are significantly more powerful than 160's because of the extra leverage from the braking surface being further from the hub (if that makes sense.)
But, 160mm should still give you more than enough power to easily lock the back wheel. Beyond that point then you can't stop any faster anyway.
Personally, as above, just check they're straight, clean them up and they'll be good to go.

EDIT: For what it's worth, both my MTB's run 160mm on the back and 185's on the front as the rear tyre only offers limited breaking anyway, it works well.
If you did ever decide to up the rotor size on the front, make sure that your forks can take the extra strain. (manufacturers will provide the info)

 

[silk186]

Thanks Panter, I didn't know about checking the fork specs. I have RockShox Tora 318 SL, not sure in the manual where to check .
Until recently I didn't even know that they came in different sizes. When I changed my rear cassette from an 8 to a 9 speed I was recommended to change my chain.
Just wanted to make sure it wasn't the same with disc brakes and rotors. I'm mainly asking in case I see a good discount in January. Based on your recommendations I will save my money and just get the brakes unless the brakes rotor combo deal is near the same price.

 

[Panter]

Thanks Panter, I didn't know about checking the fork specs. I have RockShox Tora 318 SL, not sure in the manual where to check .
Until recently I didn't even know that they came in different sizes. When I changed my rear cassette from an 8 to a 9 speed I was recommended to change my chain.
Just wanted to make sure it wasn't the same with disc brakes and rotors. I'm mainly asking in case I see a good discount in January. Based on your recommendations I will save my money and just get the brakes unless the brakes rotor combo deal is near the same price.

It's been a while since I needed a manual for mine, but I seem to remember that Rockshox had a pretty good online selection of downloads that should give you the info. Good luck!

 

[Yellow Saddle]

You choose disc size according to your heat dissipation needs, not braking force. Most brakes, nevermind disc brakes, will lock the wheel or throw you over the handlebar.

180mm and 203mm discs are for trail and downhill use, whilst 160mm is fine for cross country MTBs and 140mm is fine for road bikes if you buy the Shimano Freeza discs with aluminium cooling fins and core.

You need to get bigger discs if
1) You regularly experience brake fade from prolonged brake application.
2) If your discs are burnt blue, rather than yellow or dull brown.

Then, your existing discs will be fine, but remember to bed them in properly each time you change pads or like you want to do, change calipers with new pads inside.

You also have a choice of disc pad material - metal for super heavy duty use such as downhill and trail or, extreme wet riding off-road. If you are riding on sealed roads in the wet, you're better off with resin pads which work well in the wet (albeit don't last long in wet gritty conditions). Metal pads last long in the wet but require higher operating temperatures to work properly. They are also very noisy.

 

[I like Skol]

If you are riding on sealed roads in the wet, you're better off with resin pads which work well in the wet (albeit don't last long in wet gritty conditions). Metal pads last long in the wet but require higher operating temperatures to work properly. They are also very noisy.

This is the exact opposite of my experience with pads on my commuter bike. I have always found resin pads to give inconsistent braking performance, be extremely noisy when damp or wet and have a short service life, often requiring replacement due to poor friction characteristics when there is still a good third of the 'meat' left. Metallic pads have proven to give reliable performance in all weathers, rarely squeal or graunch when wet and give consistent braking right throughout the life until the metal backing plate is reached

 

[Klassikbike]

Resin Pads: Stronger bite and brake force, usually less noisy but wear out much quicker (Sometimes cheaper or lower end discs are not made for resin pad usage and thus require metal pads)

Metal Pads: Slightly less strong brake force (Easily enough for almost everyone), noisy when wet and last a long time

-Pads also need to be bedded in with the disc rotors for optimal performance
-Pads can glaze (Usually when not bedded in correctly or only used for small light braking)
-Pads/Rotors will loose almost all performance when in contaminated (Oil,...)

 

[silk186]

Excellent, thanks for all the information