Perpetrator of Lawsuits
Big Rotor Retrofit for Magura Martas
I just bought a 2003 Cannondale Jekyll with Marta discs (160 mm), and after taking it down Mathis at Aliso Woods, noticed that the front brake faded somewhat and the rotor turned blue. (Admittedly I was on the brakes all the way down because it's a new bike and I was getting used to it.) The caliper and rotor were quite hot. I weigh 265 and the bike is another ~30, so all told I'm asking the brakes to stop about 300 lbs.
Further, although 90% of my riding is XC in the SoCal area, I do want to go to Big Bear for some weekend warrior downhill runs (i.e. NOT racing, just mellow DH with a few buddies).
As such, I want to go to a bigger front rotor. I called Magura and Jimi told me that the new 180mm wavy Louise FR rotor & caliper adapter would work, but that Magura had nothing bigger than that that would fit for the Martas.
My question to you is this:
(1) Has anyone gone up to the Louise FR 180mm wavy rotors with their Marta calipers, and if so, what sort of improvement did you see?
(2) Has anyone gone bigger than 180mm with the Martas, and if so, how'd you do it and how'd it work?
(3) Whether or not you have personal experience with the Martas in this type of situation, in general what sort of benifit do you think I'll see from the 180mm rotor over the 160mm, (i.e. how much better do they really cool, modulate, how much more power, etc.) and will that do the trick for the sort of riding I've proposed, or am I out of my mind?
Thanks in advance for all your help.
I can answer #3...
Marta is definitely not designed to stop 300# going downhill for prolonged periods.
I previously jumped from 160 Louise to 180 Louise FR and noticed a big jump in stopping power. Modulation is about the same. They definitely don't seem to overheat as much. On the smaller rotor sometimes the lever would get real stiff due to the fluid overheating and expanding. I haven't experienced that with Louise FR, although to be fair, magura has also changed their fluid during that interval.
I don't know of any adaptor that will allow you to accomodate a 180mm with Marta. The other option is ask Jimi if you could just buy a Louise FR front caliper for around $50 and use it with your Marta master. i don't see why it wouldn't work.
Life....the original terminal illness
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Correct me if i'm wrong but.. As far as i know louise / louise fr levers aren't compatable with marta calipers.. thus i don' t think the marta lever will work with louise calipers.
I personally think you're pushing the limts of what the marta was designed to do. Given your riding description and weight it seems you need something else.. You can easily sell those martas and get louise's or something else.
Not sure about that
but I bet either of these guys would know:
Life....the original terminal illness
First, go back to your LBS and bonk them on the head with a tire pump, they never should have sold you those brakes for the type of riding you planned on doing, they should have traded out for some Louise FR's. Second, a 180mm rotor is going to be max if Jimi says so. If you go bigger I am sure it will void the warranty, it is also way beyond what the brake was designed to do. Last thing you want your brake to do is fail on a DH run up at Big Bear. Personally I would trade the Marta's for some Louise FR's, then you could go all the way up to a set of 210mm front and 190mm rear rotors if you wanted. I have a 210mm front and it is huge, but with guys our size it is not as grabby as it would be for a 165lb rider. BTW with me and my bike plus gear I am pushing 310lbs.... I am using Gustav's which is more than you may want, but they stop when ever I need them to. I really think the Louise FR's are more what you need. Just my $.02
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