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Anyone using 8" disc rotors for XC?

gling

Chimp
Apr 23, 2006
8
0
To be more specific, aggressive XC/enduro oriented.

I ride trails that are are scattered with some steep and rough slopes and found that my 6" rotors (Hayes HFX 9) are not stopping me fast enough or gets very very hot. I am assuming 8" rotors will benefit me in such circumstances but wanted to get some feedback before I get them. Also, What about an 8"-front - 6"-rear combo? Anyone using this setup?

Still somewhat new to the sport.

Thanks.
 

sanjuro

Tube Smuggler
Sep 13, 2004
17,373
0
SF
3 things:

1. Hayes are not exactly the best brakes, which could be the cause of your brake fade, although an 8 inch rotor on this site is very common.
2. Not all forks can accomodate an 8 inch rotor.
3. What is your body weight?
 

gling

Chimp
Apr 23, 2006
8
0
Thanks for the response.

I weigh 150 lbs and the brakes are fine. It's just that I really tend to plow down things at a rather fast pace and brake only when I need to. The catch is, "only when I need to". And when I do, the 6" don't really stop me in time for a quick turn or slow me down enough to evade an obstacle like a tree.

I know my fork and frame can take 8" rotors though the fact that it is a QR fork may draw some controversial comments. I am aware of the mechanical limits and possible failures of such a combination.
 

blue

boob hater
Jan 24, 2004
10,160
2
california
As long as you're aware of the risks (and willing to take them), I see no problem in running an 8 inch rotor in the front...I know plenty of people who do for XC.
 

gling

Chimp
Apr 23, 2006
8
0
Next question is: would an 8" in the rear help much? From what I understand, the front makes the most difference.

Thanks.
 

Vulcan

Chimp
Oct 24, 2004
66
0
gling said:
Thanks for the response.

I weigh 150 lbs and the brakes are fine. It's just that I really tend to plow down things at a rather fast pace and brake only when I need to. The catch is, "only when I need to". And when I do, the 6" don't really stop me in time for a quick turn or slow me down enough to evade an obstacle like a tree.

I know my fork and frame can take 8" rotors though the fact that it is a QR fork may draw some controversial comments. I am aware of the mechanical limits and possible failures of such a combination.
At 150lb there is no way you should need a 8" rotor on an XC bike. A 7" rotor might be worth considering, but 8" is total and absolute overkill. Generaly, that extra power comes at the cost of modulation, which in my opinion is very important up front.
 

gling

Chimp
Apr 23, 2006
8
0
Vulcan,

Thanks for the heads up. I just thought a larger rotor would help and suggested the 8" as it is more common. I've heard of the 7" and will look into it a bit more. Thanks for the heads up.

Cheers.

P/s: Is that bike in your icon a Fuel?
 

Vulcan

Chimp
Oct 24, 2004
66
0
gling said:
Vulcan,

Thanks for the heads up. I just thought a larger rotor would help and suggested the 8" as it is more common. I've heard of the 7" and will look into it a bit more. Thanks for the heads up.

Cheers.

P/s: Is that bike in your icon a Fuel?
Nope its a MKIII... I used to have one.

the 7" rotor shoudl be a good balance.. Also, make sure your pads are not contaminated. I had HFX-9s with 6" rotors and I could have easily thrown myself over the bars if I grabbed a handfull of brake.
 

66

Monkey
Jul 17, 2003
489
0
east of Seattle
blue said:
Eh, not really. You don't even need an 8 in the rear for DH...The front is what counts the most.
front is 70% of the power but in DH you ride the rear much more then the front. When i get brake fade, it's in the back before the front, always.
 

oldfart

Turbo Monkey
Jul 5, 2001
1,206
24
North Van
It is really terrain dependant. I can see a bigger front rotor for sure and I considered it myself. I weigh less than you at 145# and the North Shore is nothing but long steep decents. There are times when you're going into a corner a little too hot and brakes aren't strong enough. Another thing though. A larger rotor gives you better modulation because you don't have to squeeze as hard to get the same braking effect. Plus better cooling.