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Discussion Starter · #1 ·
Does any one know why the Rigs came with the 80mm setting on the Reba. Has any one changed there Reba from 80 mm to 100mm? How did it ride?

Also I was told that the 205mm rotor is a no no on the Reba, any one want to chime in?

Thanks Keener
 

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Keener said:
Also I was told that the 205mm rotor is a no no on the Reba, any one want to chime in?
...are silent to this. To paraphrase, "...use only disc brakes...and mount in provided holes...".

I say use them if you got them. I would.

Sean
 

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205mm

Keener said:
Does any one know why the Rigs came with the 80mm setting on the Reba. Has any one changed there Reba from 80 mm to 100mm? How did it ride?

Also I was told that the 205mm rotor is a no no on the Reba, any one want to chime in?

Thanks Keener
Rule of thumb is that 205mm rotors are not recommended unless you use a 20mm TA hub and fork. I am a big guy running 180's on my Rig and there is power-a-plenty :)
 

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29Inches said:
Rule of thumb is that 205mm rotors are not recommended unless you use a 20mm TA hub and fork. I am a big guy running 180�s on my Rig and there is power-a-plenty :)
Marzocchi doesn't officially support anything more than the 160mm rotors on their forks using a quick release skewer. I would imagine that RockShox may have "issues" with a 205mm rotor being used on the REBA with a QR skewer as well. I would say proceed with caution and always check for any structural damage on the fork leg or around the disc mount tab before every ride. Always check your QRelease skewer for tightness and consider safety.

I run the 185mm rotors on my Marzocchi fork and KM fork even though it is not officially supported on the Zoke. I do, however, check before every ride to make sure all is well on both forks.

BB
 

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Discussion Starter · #7 ·
On the subject of disk size loading the QR.
I have this thought that any size disk that stops the bike from a speed of "X" in "D" feet will place the same amount of force on the QR.
The energy (that stays the same) just gets more cooling area on a bigger disk. ( and the caliper will need less force)
Braking distance should be limited by the friction of the tire, not the pad /rotor/caliper.

Does this make sense? Or am I all wet?
 

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As you brake harder from the front, more weight is shifted to the front, who gets more grip, so you can brake even arder.

It's very difficult to lock a front tire braking progressively. A big disk will put higher loads than a little one.
 

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Keener said:
On the subject of disk size loading the QR.
I have this thought that any size disk that stops the bike from a speed of "X" in "D" feet will place the same amount of force on the QR.
The energy (that stays the same) just gets more cooling area on a bigger disk. ( and the caliper will need less force)
Braking distance should be limited by the friction of the tire, not the pad /rotor/caliper.

Does this make sense? Or am I all wet?
You're mostly dry. If the stopping distance is the same, and it is, the larger disc has a longer moment arm (like a lever) and creates the same braking moment with less force at the caliper and QR.

A more powerful brake only provides shorter stopping distance to a point - after that it's limited by your skill in keeping the back wheel on the ground, but unweighted. If your brake is powerful enough to do an endo or stoppie, you can achieve the shortest possible stopping distance. Larger rotors provide less fork flex, better modulation and less fade but not shorter stopping distances.
 
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