Mountain Biking - disc brake thoughts, questions

I'm preparing for a winter bike building project, need your thoughts on disc brakes/ wheelsets. I've seen in the catalogs that there are 2 main standards for mounts (right?), which is best and why? Also:

- 6" or 8"?
- cable or hydraulic?
- best wheelset for a moderate downhill rig? (probably 2.5" tires)

TIA

6" rotors should be plenty for most uses. Unless your doing downhill.
Mechanical: Avid CPS
Hydraulic: Hayes
Personally I love my Avids and would get them again over hydros, but I'm sure others will disagree.
I'm not sure what I would recommend for wheelsets. I'll let others who have tried more answer that one.

I have sun singletracks with 2.5 tires on my bighit, which could also be classified as a light DH bike (as it is set up now). They have held up well, and I also have hayes hrdraulics. The setup is nice. 6" should be enough.

Depends on riding. If you are dhing a lot on long runs 8 inch rotors are best otherwise 6inches is fine. I hate most mech disc brake but have heard wonderful things about Avids, to the point where I am considering them for my front wheel. Hydros again depends on style. I would say for freeriding or dh nothing beats Hayes while for xc I might go to hope minis as they are very light with good power.

Wheelsets are totally based on riding, size and skill. Because I am big and fairly new to biking in this terrain I opted for Mavic 321d rims which are very strong. If I was lighter (150 or less) I 'might' go with Sun Ryno lights but I have personally damaged many of those rims. Otherwise rims have to be tested. Some riders are heavy and suck and need VERY heavy rims while some guys are lighter and smoother and don't need as heavy a rim. :)

Cheers

duh! I guess my weight and riding terrain would help with your answers. I am heavy- anywhere from 190-210 depending on the season, and need to build to handle some pretty rough terrain (moderate drops, high speed DH, possibly some future 4X?). I'm old but still young enough to be an idiot.

Finished weight of the bike is not my main concern but I would like to keep it under 40 lb's, 35 would be better. This will be a winter project as I plan to scrounge around to find the parts I don't already have. About the only thing I have that I will use on this is an XTR goupo and truvativ BB. Thanks for the replies...

How about the mounts, was I right about there being 2 main standards? Which is best?

Do you want to build the wheels your self or get pre-built?
6" rotors work good unless you plan on doing a fair amount of dh. I would also go with hydrolic over cable. As to which system, I suggest Hope. M4's if you are a high speed junky or mini's if you are riding xc. I have tried every manufacturers systems and found that Hope have the best modulation, heat disapation and they look the best.

Most bikes these days have I.S. (international standard) mounts. If you get a system that is buit for I.S. you will not need any adaptors which will reduce the areas that might flex under hard braking (I have only seen a few riders with this problem).

If you do go with hydros and the system you get uses standard brake fluid then I would recomend draining the fluid in them and replacing it with DOT 5.1, it has a higher boiling point.

Slainte:beer:

I am set up to build my own wheels, in fact I prefer to do my own.

The other style of mount is the "Post" mount. This is the style that Manitou uses. There are numerous adapters and I've never had a problem with any flex or play in the adapters. As a matter of fact it allows for a bit more adjustment so you can "fine" tune the caliper location and eliminate any rubbing.

Between Cable and Hydraulic; it boils down to how hard you're going to ride and how much money you have to spend. The new mechanicals are "almost" as good as hydros, but do not have the "feel" and strength of hydros. Close, but not quite!

I've not owned, but have ridden my bud's bike that has Shimano XT's (8") and he swapped the stock pads out for EBC Red pads with much success.

Rims: I'm running a set of Mavic D321's they are full on disc specific DH rim, and it's heavy and strong. If I were to build up another set, I'd probably consider the F219 (more of a Freeride rim) or the Trailking or Trailpimp's from Atom Lab. www.atomlab.com these are probably the biggest badest burliest rims on the market! Azonic used to make a rim called the "Butcher" which was also pretty burly! Don't know if they're still making it.

While your at atomlab, check out their "Ballistic" pedals or Trailking pedals if you want some super strong platforms.

My suggestion for wheels, Mavic is now selling the 2003 DEE-MAX rims seperatly so you do not have to buy a compleat wheel. Here is how I would build 'em:

Hubs : Hadley dh 20mm through axcel front / 12mm t.a. in back
Spokes/niples : DT Swiss 14g black/ brass niples
Rims : Mavic DEE-MAX fr & rr
Tires : Maxis SwampThing 2.5 (super tacky up front, 60a
compound in back)

I have not priced the rims yet but I would assume that they will be pricey, probably around 100+ USD.

I currently am running Sun SingleTracks on my dh rig and on my freeride rig I have a Sun DBLwide in back and a Mavic 321D in front. I have had no problems with any of the rims and if properly built they all can take some serious abuse.
Also the rims that a2 mentioned are very good as well.

If you are trying to keep the price down on the brakes then I would suggest using Hays with 8" rotors. Their 2003 models are sweet. If the price is not a problem then I would say go for the Hopes. If Grimeca ever gets off their arsses and gets the system 17 on the market I would say get a pair of those but they will run you 400USD per wheel with replacement pads per caliper costing 100USD.

Slainte:beer:

Thanks guys, as always you are a wealth of knowledge..