[Closed] Increasing rotor size worth it?

I run 180/160 normally but going on holiday, or "big" days, I add a 293 to the front and move the front to the rear. Then I take the 160 in my spares box just in case.

Yes, you notice a difference, but only when you're placing significant demands on the system. If you're brakes are always doing what you need them to, the way you want them to, there's no point.

[quote=Onzadog ]I run 180/160 normally but going on holiday, or "big" days, I add a 293 to the front and move the front to the rear.

wow any pics

Depends if you want/need more braking force. I run 203/180 all year round.

Downside (and it can be quite substantial) is weight, it goes up with almost the cube of diameter but don't be tempted to swap to lightweight rotors with large cutouts, IME they offer less power than just going smaller so not worthwhile unless you already are on 160/140. Lever feel is more on/off. And pad life*.

Upsides are lots more power**.

*small rotors run much hotter, I used to run 160/140 and they would fade even at a trail center. But pads would last a full winter as the surface hardenes once heated (aka bedding in). Barely worth bothering with now, just run cheap sintered pads.

**More of a problem on 29ers and fat bikes as the brake size in effect has to be scaled with the tyre diameter to get the same power at a given speed (power =frictional force x disk velocity, 29ers rotate about 10% slower so 10% more disk offsets that). So 203/180 on a 29er doesn't feel that much different to how 180/160 did on a 26er.

I initially set my bike up 160 front and back because that's what I had lying round. I upgraded the front to 180 and it's better so I would say stepping up again will be better still. To be honest though I'm now happy with the braking so wouldn't go bigger.

I'm always impressed with the power of disc brakes. My motorbike can stop from silly speeds with just a slight two fingered pull. Perhaps we need to go to twin disc front setups!

Mr Spoon - Running new (15 rides) XT brakes with plenty of stopping power TBH, even for my large carcass.
More of a generic question as saw plenty of bikes running the bigger combo at Degla yesterday.
Intend getting a few uplift days in next year and XT 203 at great price on Wiggle...

Do you have any issues currently? If not, then it's not worth it.

If you would like a little more effective stopping power or increased cooling capacity (handy in the very hilly areas) then it is worth it at the penalty of weight, but not exactly much weight compared to what you'll gain in the first muddy trail you go down.

I moved up to a 203/183 combo a while ago and haven't looked back. I do like having excess power on tap, and just occasionally they get a good toasting if its steep and long enough.

Short answer
Yes.

I swapped my 160 rear for a 180 (so 180 both ends) I’m 99% sure I can tell the difference.

I remember having a hard tail with 160 front and rear (avid cable disks) that felt quite hard to stop..

I have 203 front and back, enables me to use rear brake as much as I want without fade. I’d rather have amazing brakes than a few less grams, it really isn’t much difference in weight. I might be imagining it but I think you get a finer control when the rotors are larger too, certainly takes less effort to get to the point of locking too.

Deffo

Well worth the marginal weight increase for more power and modulation and less fade

Larger rotors will give more power but less modulation / feel.

Happy with 180 everywhere (UK, Alps, etc) to be honest, best all round for feel and power.

Mine was much improved with a bigger rotor up front. Not bothered at the back, but may consider it. They are wear items and need changing periodically anyway so cost isn't that big a deal, especially if you have a spares box of adapters

180mm both ends here, no loss of feeling.

It depends on how big you are. I'm big.

I put a 160mm rotor on a new build recently and it felt terrible. Replaced it with a 180mm and it was a huge improvement.

203 F&R - notice 180 F&R as being not as powerful and 160s are just awful

Larger rotors will give more power but less modulation / feel.

Complete rubbish. Long lever travel with big rotors gives you so much more control AND power than smaller rotors.

[IMG] [/IMG]

Have to agree. Only downside of bigger rotors is a bit of weight

They can also be more sensitive to setup issues

I changed my rotor to a 180 on the rear and found it too grabby. This was with a shimano brake. With a 160 rotor it felt like I could modulate the power more easily.

I would guess those using brakes with better modulation would not have the same issue?

I would guess those using brakes with better modulation would not have the same issue?

No, I found exactly the same going from a 160mm to 183mm disc on the back of my full suss and that's with Hope's which are pretty good for modulation.