Bigger rotors better braking? Hows and whys explained | mountain biking

It’s been some time since I have picked up mountain biking and recently I started noticing my braking power was gradually decreasing over time and did some thorough research the information is there but it was spread in pieces so I decided to write an article a complete guide on how rotors work and many other questions related to rotors.

If there is a safety measure after helmets for mountain bikers then it would always be braking and disc brakes have always been ignored or somewhat not explained completely.

There is a ton of information available on the internet with big holes, All the content creators do try their best to answer almost all of the information regarding specific topics better there are always a few questions left.

One of the biggest questions frequently asked from mountain bikers on the internet or in real life is if bigger rotor brakes are better than smaller ones? and what effects would they show on your bike or braking rotors.

Do bigger rotors stop better :

The simplest answer to your question is.

While bigger motors do provide more braking power but you might not find the results you are looking for since braking power is not dependent on the rotors only and sometimes bigger rotors may even give the same results or even worse here’s how you can effectively increase braking power and not destroy your rotor in the process.

In case you are thinking of changing your rotors, First of all, I would advise you against changing your motors, If the motors in your bikes were working perfectly until recently then there is no point in changing them, The motors that the manufacturers put in your bikes are the most suited for them, and if you are feeling that your brakes are losing grips then try to troubleshoot the problem may be rotors are fine and there’s some other issue.

To troubleshoot the problem with your brakes here are some ways

  • check pads
  • bleed the brakes and refill
  • check if the brake lever hasn’t become loose
  • check the fluid valve (located right next to the brake lever a tiny watch-wind-like dial)

In most cases, the problem is with the braking pads, and if you are using organic pads all the more reasons to check their condition.

The next problem that you could be facing is the braking fluid sometimes the water gets into the fluid which can result in braking power reduction or failure.

If you are using a wire system check if the wires haven’t loosened.

and lastly, check the brake fluid valve you will see a + and – next to the brake fluid valve what it means is if you turn it in a plus direction it will increase your braking what happens is the fluid travels faster or slower when you rotate the fluid valve.

If seemingly there are no problems and still the brakes are fine but you are still lacking the braking power then you can look into the bigger rotors, mostly used sizes are

  • 160 mm
  • 180 mm
  • 203 mm

Setting up new rotors and testing :

Rotors and braking depend more on the terrain if you are riding mild tracks then 160 mm rotor and organic pads have more than enough braking power if you are not satisfied with the results then I think you should switch to metallic pads instead of switching to a bigger motor give them some time to sink in with the rotors and they are more than enough to stop your bike in less then half the time it took before.

If you are a park guy then 203mm in front and 180 mm in the bike are enough you should try both organic and metallic pads if organic fails then metallic pads given the time provide enough braking power.

disc brake rotor

 

and if you are somewhere in the middle then 18mm in the front and 160mm in the back are enough for you again use organic pads first before using metallic pads.

Are all-mountain bike disc brakes the same :

Usually, this question pops on the internet from time to time if all the mountain bike disc brakes are the same, well the short answer would be

Yes, all the mountain bike disc brakes are the same there is a variation in sizes of the rotors and pads specification like organic or metallic pads they are almost the same.

As I have mentioned above mountain bike disc rotors have different sizes and are either metallic or organic pad compatible.

Can you install metallic pads on any rotor :

You can install the metallic pads on any rotors and vice versa but if the specified rotor that you are using is made for organic pads then the metallic pads will take no time chewing on the rotor at first it will make a loud noise when you use the brakes.

And the worst-case scenario the rotors will get deformed so I would highly recommend against using metallic pads on any rotor without knowing if they are compatible with the rotor or not.

How long do mountain bikes rotors last :

There is not a certain number to this answer but I will do my best to answer the question.

Mtb disc rotors are dependent on the pad material(metallic/semi-metallic/resin), terrain, and the load your riding style is also a counted factor in it as well taking everything into account they can last from somewhere 6 months-1 year.

If you are using the metallic or semi-metallic pads then the pads will chew through the rotors pretty fast but if you are using organic pads they can last longer so there is no fixed number but there are ways to check if the rotors are fine or you need to change them.

The fastest way is to test if the pads are touching the rotor or not if they are barely scratching them then it means you need to change them.

Note : if the rotors are making a noise it can be due to some dirt or debris, its not always due to rotors being useless

The next to look for is to take a good look at the rotors if you see them bending then that might be a signal as well.

The last method is for trial and error you can take your bike on the road and draw a line and check how well it is braking if the average number is not looking good you might need a change but check the pads before changing the rotor would be a great idea.

Are mountain bike disc rotors interchangeable :

Again the simplest answer would be

Yes, they are interchangeable but do perform some checks before you do that if you are swapping smaller rotors with the bigger ones and vice versa they may perform better or worse so you shouldn’t do it on the track.

Depending on certain conditions they can perform better or worse if you swap the bigger rotor in the front tire with the smaller rotor it will greatly decrease your braking power drastically and vice versa.

Metallic pads for winter :

Metallic pads are your way to go in winter if you are an Mtb enthusiast and would like to drive in the snow as you did in summer then metallic pads are a better choice do not use organic/resin pads in the winter because in most cases resin pads will fail you also need that extra braking power in winter since the land is mostly moist.

Semi-metallic pads are the same as well they simply lack that braking power so its best go with metallic they will chew out your motor disc but that’s in everyone’s favour i guess.

 

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