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Is a 180mm front really that much better than a 160mm front?

8526 Views 7 Replies 7 Participants Last post by  Strauss95
I'm sure that this has been discussed a million times on these forums, so I apologize in advance for the redundancy. However, I'm really struggling with this decision and unfortunately, the search feature on MTBR is currently disabled (at least on my computer).

Anyway, I'm currently in the market for some new brakes and right now I have a 160mm/160mm Hayes Mag XC set up. I weigh 162 lbs and ride mostly what I would call aggressive XC. I live in Northern California and usually go to Downieville to hit the 16 mile downhill course once a year as well. Obviously I use my front brake quite a bit, but I wouldn't say that I am particularly heavy on it. In fact, I can't really ever even think of a time when I really felt like I was significantly underpowered with the front brake. That being said, it seems that using a 180/160 rotor combo is the popular choice for most people on these forums. Maybe I just don't know any better and don't know what I'm missing because I've never used anything but the 160mm rotor in front???

If you've stuck with me this far, I really appreciate it. So my question is this... do I stick with my current rotor sizes which has worked pretty well for me up to this point, or should I switch to a 180mm front which seems to be the direction that most people are going? I should also mention that I do tend to suffer from WWS (weight weenie syndrome) from time to time, so this is ultimately what makes moving to the 180mm front such a difficult decision for me.

Thanks for your input.
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As you would imagine, a 180mm rotor is 9/8X as powerful as a 160mm. There's really no sense in changing rotor size if the current setup works fine. Changing pad compound makes a much bigger difference in feel if you must.

A 180mm also harder to overheat and fade but again if yours work fine, there's no need to change.
I have never had any problem locking up the front wheel with one finger using a 160 mm rotor. It is swell that a 180 is more powerful, but if the it’s locked, it’s locked. It’s like putting 300 hp in a golf cart. I think the big advantage is that the larger rotor dissipates more heat, so on very long descents where you are using the brakes for a prolonged period, a larger rotor is less likely to heat up and fade. Do you take very long descents that cause your brakes to heat and fade? If not, then having a larger rotor won’t help much unless your brakes lack the power to easily stop the wheel.
Agreed....

if you have no problems with a 160/160 set up, there is no reason to change. The main reasons that most go with a larger rotor in front are, increased resistance to heat fade during heavy braking, increased power due to larger lever moment, and it tends to even out the difference in lever pull between the front and rear. Since most braking takes place with the front and it requires more force up front because of weight shift while braking, you can get a distinct feeling of uneven lever pull requirements between the front and rear brake. Most people compensate for this without even thinking about it. They simply pull the rear lever less firmly than they do the front. The result is the bike slows down as it's supposed to without locking up the rear wheel etc. However this can be changed by running a larger rotor in front and smaller in the rear. It evens out the lever pull between front and rear barkes, you don't have to concetrate as much. Like I said, people do this on same size front and rear rotors without even thinking about it.

Bottom line is, if your current set up works, don't mess with it. There are reasons for going with a larger front rotor. But you don't seem to have any of the issues that would require it.

Good Dirt
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Taz8 said:
Maybe I just don't know any better and don't know what I'm missing because I've never used anything but the 160mm rotor in front???
4" XC bike - I started with 160/140 hydraulics, went to 185/160 mechanicals. Awesome

switched bikes...

6" AM bike - Started with 185/160 mechanicals, then 185/185 mechanicals.

Now I'm back at 160/160 hydraulics....

and as soon as I get the broken bolt out of my fork I will be at 180/160 hydraulic again on the 6" bike.

160 works.
180/160 works better.
185/185 was overkill for aggro XC at 145lb.

Do you need it? No.
Will it be a noticeable performance upgrade? Yes.
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debusama said:
I have never had any problem locking up the front wheel with one finger using a 160 mm rotor. It is swell that a 180 is more powerful, but if the it's locked, it's locked. It's like putting 300 hp in a golf cart. I think the big advantage is that the larger rotor dissipates more heat, so on very long descents where you are using the brakes for a prolonged period, a larger rotor is less likely to heat up and fade. Do you take very long descents that cause your brakes to heat and fade? If not, then having a larger rotor won't help much unless your brakes lack the power to easily stop the wheel.
Right on the money. I still rock V brakes (I know, I know), but the analogy is just like setting up brakes on automobiles. Will huge rotors help you? Not really without the matching giant calipers. The only place larger rotors help is with fade. Pads will have more of a change in your braking feel.
Thanks for the info guys. I still haven't decided what I will do yet, but I'm leaning towards trying the 180/160 combo. Thanks again.
I was getting brake fade on long downhills with my 160mm F/R combo(Hayes Stokers BTW), so I upgraded to a 203mm rotor up front and noticed a HUGE difference in front braking power. Now that I have gotten used to the lever feel with the larger rotor, I love it. Plus I have absolutely ZERO brake fade now down the same hills that used to overheat the 160mm up front. All said and done I am very happy I made the upgrade, currently I am 100% satisfied with my brakes.

I say give it a try. If you don't like it you can always throw the 160mm back on. Just don't forget the proper adapter for the 180mm rotor.
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