Hi everyone, I have recently bought a second hand specialized xc and the front disc is warped/buckled. Its a 180 but I'm thinking as i need a new one I might upgrade to 203mm. Not sure though if for everyday xc singletrack the 203 will be of any benefit or not. Are the bigger discs purely for more DH so to dissipate heat better?
Thinking of buying new discs... is bigger better?
203 is not necessary for everyday xc singletrack and they are heavier. Bigger discs do dissipate heat better but also offer mechanical advantage for braking by placing the caliper further out and hence better leverage. I have used 203 for everyday riding because it was all I had at the time - didn't notice much difference either in terms of braking performance or weight - go ahead and try it if you want to!
I use 160mms mostly and they work well for me ( I am sub 11 stone )- even for the likes of snowdon / cadair idris / lakes stuff and as I like v techy trails I think they gibe me more clearance as and in the past i have bent my bigger rotors more often than my smaller ones - however the bigger ones do grab more and 'feel' more powerful but they add more weight...
a 180/160 combo is great as is a 160/160 for normal trails
hope that helps
There's been threads on here discussing the issue that too big a disc means the heat is dissipated too quickly, meaning that pads wear out too quickly. Itend to agree with this point, despite having boiled my freshly-bled brakes on the slopes of the Alps.
Frankly, unless you're especially heavy or ride especially steep and long descents then there is no need for anything bigger than 160. IMHO of course.
Edit: here's one: http://singletrackworld.com/forum/topic/rotor-size-and-pad-wear
Hamish is right a 203 will be heavier, so leave a powerbar at home, it'd weigh more than the difference....
Snowpaul has the most salient point, how heavy are you? I wouldnt dream of using 160s anymore, tried 180s and thought they were crap. 203 front and rear all day everyday for me. But then I'm seventeen stone without associated bike gear.
The bigger brakes give me way more stopping power and because of this I know I can always brake later and with less effort.
I use a 180/160 combination at 13 stone, with no issues. Don't forget that if you change disc size, you'll need another caliper mount adapter...
i also run a 203, sintered pads make more of an improvement than any other disc size ive ever ran imo
I find that moving up from a 160 to a 180 gives me alot more power at the expense of "feel" and it is not so featherable
But on the back I always run a 140 disc because I do not want alot of power at the back end because a locked wheel does not grip
Going back to my motorbike days 70% of all breaking is dome by the front brakes and the rear is for control think about it motorbikes have a double disc front and a small disc at the back
Better stopping power? Yes
cheers for your comments, I think I'll give a 203 up front a go. The current front (shimano) feel is a lot spongier than the bite my avid j3 had on my last bike, maybe the 203 will sharpen it up. I don't do mega downhills (dalby, gisburn, stainburn) but being an ex trials rider I do like the feel of a keen front brake. oh and I'm around 12 stone so an average mass to stop I guess.
Happy new year everyone.
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