Mountain Bike Reviews Forum banner
1 - 20 of 42 Posts

·
Registered
Joined
·
153 Posts
Discussion Starter · #1 ·
Just installed Formula "The One" brakes on my Spec Enduro. I'm running 203mm on he front and 160mm in the back. The kid at my LBS recommended I replace the rear with a 185mm rotor without giving a clear reason why.

I'm pretty light at 170lbs riding a 28lb Enduro. Can anyone share their thoughts on how I can benefit from this upgrade?

Thanks
 

·
Registered
Joined
·
201 Posts
jdizzle707 said:
Just installed Formula "The One" brakes on my Spec Enduro. I'm running 203mm on he front and 160mm in the back. The kid at my LBS recommended I replace the rear with a 185mm rotor without giving a clear reason why.

I'm pretty light at 170lbs riding a 28lb Enduro. Can anyone share their thoughts on how I can benefit from this upgrade?

Thanks
weight savings, particularly JUST aft of the saddle, right about where your wallet sits

I rocked lift assist riding with a 203 front, 160 rear (HFX-9's), and had no issue. The bike is fine as is, you could even get away with a 185 front if you wanted to
 

·
trail addict
Joined
·
1,866 Posts
The_Pitbull said:
I rocked lift assist riding with a 203 front, 160 rear (HFX-9's), and had no issue.
+1.... Except XTs instead of HFX-9. Unless you have really long descents or weigh a lot, any more than 160 in the rear doesn't make sense to me.... although it won't hurt anything, either.
 

·
Bicyclochondriac.
Joined
·
15,210 Posts
jdizzle707 said:
Just installed Formula "The One" brakes on my Spec Enduro. I'm running 203mm on he front and 160mm in the back. The kid at my LBS recommended I replace the rear with a 185mm rotor without giving a clear reason why.

I'm pretty light at 170lbs riding a 28lb Enduro. Can anyone share their thoughts on how I can benefit from this upgrade?

Thanks
I have experimented with different sized rotors on the front (settled on 185), but have never seen any need for bigger than 160 on the rear. If anything I think I would be locking the rear up too easily with a larger rotor. I'm sure for a FR or DH bike it would be different, but for a 32 lb AM bike I like the 160 in the rear. And I am 20 lbs heavier than you.
 

·
err, 27.5+
Joined
·
4,928 Posts
No, you don't need the 185mm rotor. At your weight the 160mm should give enough stopping power.

That said, there are other reasons to run bigger rotors. Heat dissipation is better, so braking is more consistent. Larger rotors can give a bit more modulation. Hand fatigue will be lessened as you don't have to pull as hard on the lever. I also like a big rotor as I can use a resin/organic pad for more modulation and silent braking.
 

·
Registered
Joined
·
1,432 Posts
AL29er said:
No, you don't need the 185mm rotor. At your weight the 160mm should give enough stopping power.

That said, there are other reasons to run bigger rotors. Heat dissipation is better, so braking is more consistent. Larger rotors can give a bit more modulation. Hand fatigue will be lessened as you don't have to pull as hard on the lever. I also like a big rotor as I can use a resin/organic pad for more modulation and silent braking.
X2 :thumbsup: Especially on the bold part. Everyone assumes smaller rotors give better modulation. I think they're a crutch for the heavy handed people.
 

·
Bicyclochondriac.
Joined
·
15,210 Posts
BuickGN said:
X2 :thumbsup: Especially on the bold part. Everyone assumes smaller rotors give better modulation. I think they're a crutch for the heavy handed people.
And bigger ones are a crutch for weak, sissy fingers.
 

·
Bicyclochondriac.
Joined
·
15,210 Posts
BuickGN said:
Or the ones that want less fade and better modulation. I've got an extremely strong grip but it doesn't mean I want to use it all the time.
You get fade on your REAR brake? Give me a break:rolleyes:

I totally disagree that it is better modulation. IMO, it is worse. Of course, modulation seems to mean different things for different people, but in my experience, you get better control over the point at which you lock up the wheels with a smaller rotor.
 

·
err, 27.5+
Joined
·
4,928 Posts
It boils down to setup. Fade in the rear brake, yep never had fade in the front ;). I am probably a 60% rear / 40% front brake user. I have no interest in joining the camp that says 90% of braking is done by the front brake. Only way I am putting that much brake input on the front is in a straight line on a smooth downhill.

Modulation vs. control, there may be some difference in perception. I agree that it is harder to lock up a smaller rotor, so if your definition of modulation is dependent on you having to squeeze the bejesus out of your lever to lock the wheel then a 6in would by that defn. have better modulation. Basically you only can lock the rotor by really clamping down on it. Okay, I can see that perspective.

Having not seen the south side of 200lb since I was in puberty I have a bit of a different view on the small rotors and modulation. On XC they work fine, but on an extended DH trail 2+minutes of heavy braking in steep terrain not so well. I cook the pads and rotors. Once they glaze or get too hot the modulation is gone. It is either off or on. So minimal power until I really clamp down and then finally some power, but no modulation between. Some people like this sensation, esp on a 6/8in rotor combo, as they never lockup the rear wheel so they go faster and leave the O'sh!t moments up to the front to save.
 

·
Bicyclochondriac.
Joined
·
15,210 Posts
AL29er said:
It boils down to setup. Fade in the rear brake, yep never had fade in the front ;). I am probably a 60% rear / 40% front brake user. I have no interest in joining the camp that says 90% of braking is done by the front brake. Only way I am putting that much brake input on the front is in a straight line on a smooth downhill.

Modulation vs. control, there may be some difference in perception. I agree that it is harder to lock up a smaller rotor, so if your definition of modulation is dependent on you having to squeeze the bejesus out of your lever to lock the wheel then a 6in would by that defn. have better modulation. Basically you only can lock the rotor by really clamping down on it. Okay, I can see that perspective.

Having not seen the south side of 200lb since I was in puberty I have a bit of a different view on the small rotors and modulation. On XC they work fine, but on an extended DH trail 2+minutes of heavy braking in steep terrain not so well. I cook the pads and rotors. Once they glaze or get too hot the modulation is gone. It is either off or on. So minimal power until I really clamp down and then finally some power, but no modulation between. Some people like this sensation, esp on a 6/8in rotor combo, as they never lockup the rear wheel so they go faster and leave the O'sh!t moments up to the front to save.
What kind of brakes do you use that a 160 on the rear takes more than modest finger pressure to lock up the wheel?:confused: Heck, even with v-brakes I could easily lock up the rear with one finger, even leaning back.

Yeah, I am in the camp of the front being where most of the braking takes place. Kind of hard to argue with physics, but I imagine if I never learned how to use the front properly, I might need a bigger rotor in the rear as well.
 

·
mbtr member
Joined
·
6,503 Posts
I'm a big fat guy with long steep descents. With 6/8 rotors the 8" is still the one that overheats first. Seems to me that if you're cooking your back brake you should stop riding it down hill.
 

·
Registered
Joined
·
30 Posts
kapusta said:
What kind of brakes do you use that a 160 on the rear takes more than modest finger pressure to lock up the wheel?:confused: Heck, even with v-brakes I could easily lock up the rear with one finger, even leaning back.

Yeah, I am in the camp of the front being where most of the braking takes place. Kind of hard to argue with physics, but I imagine if I never learned how to use the front properly, I might need a bigger rotor in the rear as well.
It depends where and how you ride. The concept that the majority of the braking power is at the front is valid in ideal conditions but it isn't always applicable to the real world. Dry and flat is a lot different than steep and wet.
 

·
Registered
Joined
·
220 Posts
Formula R1 brakes + 220 rider + 22.5 lb bike + 180mm rotor in front/160 in rear = more than adequate modulated braking power.
 

·
Registered
Joined
·
217 Posts
Well, I'm a big, fat guy that likes long, steep descents too. I NEVER lock my back brake and at 185mm it is always the brake that overheats/fades first. Never had a problem with the 203mm front overheating and it still does the majority of my braking. Also, the back brake always seems to have the problem with the pad rubbing (especially after long descents). I have to reset the back brake pistons occasionally, but never the front (on XT M775's).

I just got a set of Saints. I'll try them first at 203F/185R and if I still overheat in the rear, I'll move to 203mm rear.

The world of braking power, modulation, heating, rotor size, etc is very different for us big guys.
 

·
mbtr member
Joined
·
6,503 Posts
longdrive55 said:
The world of braking power, modulation, heating, rotor size, etc is very different for us big-ginners.
fixed. :D

Stop riding it and it won't fade.
 
1 - 20 of 42 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top