# Brake Rotor Size Recommendations for Heavy Rider



## hanknmorgan (Jan 19, 2006)

Hello. I am currently 260lbs (Down from 283 3 months ago, woohoo) and 6'4". I currently am using a set of 160mm tektro disk brakes that came on my old bike. Needless to say they suck and I am getting ready to order a set of avid bb7's. I have a Marin Rift Zone frame with a Marzocchi mx Pro fork. The fork says it can handle a 7" max disk, so I plan on running the 185mm rotor up front. Is there any benefit running a 185mm in the rear vs a 160? No doubt the 160 will be enough to lock the wheel, but my main concern is heat buildup. I have smoked the crappy tektros a few times on some long descents. I ride pretty flat here in Texas, but when I lived in California I killed these breaks and they faded big time. I ride cross country but am enjoying getting into more technical trails with a bit of speed on the descnts. The small weight difference is not much of a concern and the price difference is like $5. I have read that most people run 160 in the rear no worries, but I am bigger than most people, so I wanted to get the input of other big guys. Any suggestions, reccomendations would be appreciated. Thanks.


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## dascro (Apr 1, 2007)

I think you'll be fine with the 160 in the rear.


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## Mordy (May 31, 2006)

Always get as much brake as you can, thats my motto. I run 160 in the rear on my hard tail and 185 rear on my FS. Both do good, but you can tell the difference that theres a benefit to the 185.


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## hanknmorgan (Jan 19, 2006)

so I should run 185 on the rear as well? I will definately get the 185 for the front, mainly curious if I should stick with 160 or get some 185's on the back. Thanks.


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## hanknmorgan (Jan 19, 2006)

Sorry to double post. I just called marin and they told me that any size rotor will fit the frame in the rear, but it is designed to be used with a 160mm. Basically, a larger rotor could stress the mount more than it was designed for and could eventually weaken or even break the caliper mount. So, I have decided to go with the 160 in the back which they said would be more than enough and a good compliment to the 185 up front. Thanks for the help guys.


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## bingemtbr (Apr 1, 2004)

Go big for heat dissipitation. Larger surface area of a larger rotor will allow for more cooling time in between pad rubs. On the flats, this shouldn't be an issue but go bombing down any DH lasting longer than a few minutes and spray your rotors with a little water for a sizzling demonstration of heat retention. 

Strange but true. 

FWIW, I started with the chi-chi hydro and now run BB7's exclusively on all my bikes.


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## dascro (Apr 1, 2007)

You will be completely fine with 160 in the back. i am around 190lbs without gear and have done downhill runs with my 160 rotor in the back. I never felt limited by it. Look at cars and motorcycles and you'll see they all have smaller rotors in the back


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## SingleTrackLovr (Apr 25, 2007)

If you're sticking with the 160 on the rear look into higher quality brake pads for more stopping power.


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## xcessvnold (Apr 9, 2007)

Marin advised me against using larger than 160mm in the rear also of my FS also. So, I'm running 203mm front and 160mm rear Avid mechanicals and they work great. Also, as mentioned, you can balance the braking somewhat to your liking by using different brake pad compounds front and rear. For example, the Avid metallic pads are grabbier and higher friction, but harder to modulate than their organic pads (which wear faster). The Aztec pads seem to be a good compromise; I haven't tried any others.


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## hanknmorgan (Jan 19, 2006)

fantastic. Thanks again everyone. Any brake upgrade aside from grabbing the tire with my hand is going to be MUCH better compared to my old tektro piece of junk brakes. They are probably ok for little people on walking trails, but not big guys. I am limited to 185mm up front because of my low budget fork. So I will run the 185/160 combo and see how it goes. I'm sure it will be more than enough for my skill and riding style. If I ever need more braking I will likely need a new fork and all that anyway so no worries. Again, I appreciate all the help and input. I was stressing over what to order but I got them ordered this afternoon. I will look into pad changes if I need to once these wear out. I imagine they will work out just perfectly for what I need. Take it easy.


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## mtnbiker72 (Jan 22, 2007)

I used to run 203's front and rear...then went down to a 203/160 combo and now I'm currently at a 185/160 combo and find it to work fine with full sintered metallic pads. If I was running full DH runs (which I used to) then 203's are nice. But for all-mountain riding, the 185/160 combo feels like the perfect balance to me.

PS I've weighed as much as 230lbs with this combo, currently 215lbs (and aiming for 200lbs!)


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## hanknmorgan (Jan 19, 2006)

mtnbiker72 said:


> I used to run 203's front and rear...then went down to a 203/160 combo and now I'm currently at a 185/160 combo and find it to work fine with full sintered metallic pads. If I was running full DH runs (which I used to) then 203's are nice. But for all-mountain riding, the 185/160 combo feels like the perfect balance to me.
> 
> PS I've weighed as much as 230lbs with this combo, currently 215lbs (and aiming for 200lbs!)


Great. Thanks for the input and experience. Exactly what I was hoping to find out. And, congrats on the weight loss. I havent been riding nearly as much as I like but the little I do and eating right and I am dropping down slowly but surely. I will check out those metallic pads that have been mentioned, but I think I will run the regular ones at least for a while.


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## PanFry (Nov 9, 2007)

203mm.F/185mm.R.


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## savagemann (Jan 14, 2008)

I'm 285 w/o gear. I run a 185 front and 160 rear. Plenty of power with my Hayes Strokers. If you go bigger than 160 in the rear you lose all feel and it is pretty much either on/off braking. I like some feel and modulation, so 160 rear IMO.


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## zarr (Feb 14, 2008)

I use Avid BB7 185mm front and rear.The price is so close between the 160 & the 185 Iwent for the bigger ones front & back,and I'm way Clyde.Probablly won't hurt, even though I heard 185 rear is overkill.


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## Paul1977 (Aug 9, 2007)

Ive just upgraded from 185mm Juicy's to 203mm Stroker Trails because I was having issues with the juicy's overheating and fading on long steep sections when doing dh runs. My rotors would go blue from the heat.

It worked out to be not much dearer to buy new brakes than getting new pads rotors and adaptor for the juicy's.


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## dieseldog (Jun 16, 2004)

Definitely go 7" in the front - 8" isn't a good idea without a thru-axle. If Marin's not down with 7 in the back, go 6 with avid's sintered metallic pad and try Jagwire Ripcord compressionless brake housing for both brakes - it stiffen's the brake housing noticeably - or if you have the cash - nokon cable and housing. Less wasted power.


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## Floggus (Feb 11, 2006)

I weigh about #280. I have 185 front and 160 rear rotors with juicy 7 levers and calipes. I have boiled the fluid on them a couple of times. It's not something I would like to experience again. I recommend as big a rotor as possible for max heat dissipation.


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## willtsmith_nwi (Jan 1, 1970)

hanknmorgan said:


> so I should run 185 on the rear as well? I will definately get the 185 for the front, mainly curious if I should stick with 160 or get some 185's on the back. Thanks.


185mm is overkill on the back. Stick with the 160mm. Look at XC rigs and you will see flyweights running 140mm rotors in the rear. But ONLY in the rear.

When you brake you transfer your weight to the front so the rear loses it's effectiveness. There is no advantage to locking up the rear. In ALL cases the front rotor should be large than the rear despite what the manufacturers might ship.


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## xcessvnold (Apr 9, 2007)

Yeah, I'd agree 160mm is plenty in back, even with a 203mm in front. And if you're getting new calipers as well, I'd highly recommend the Avid BB7s. They're plenty powerful, and no worries about bleeding or brake fluid boiling (though they're not as easy to modulate as most hydraulic setups).


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## hanknmorgan (Jan 19, 2006)

My new brakes arrived yesterday. I got the 08' BB7's. Calipers and rotors and set of speed dial 7 levers as well. Great prices for such a highly regarded brake setup. I ended up going with the 185mm up front and the 160mm in the rear. OEM recommended max size for my fork and framce. There are very few descents here in San Antonio and even fewer that are long enough to worry too much about cooking rotors. I used to commute downhill when we lived in San Francisco and I got the 160's pretty hot on occasion in that situation. Anyway, I hope to get them installed tomorrow evening or thursday and I have some riding planned for this weekend. Cant wait to feel confident in my brakes and hopefully not have the rediculously annoying dragging and squeaking that seemed to happen with my tektros. My wife could always tell when my brakes were dragging on the flats because she was right on my butt with much less effort. I just wish that Avid used different rotors. Simply asthetically. I like the look of the cleansweeps or similar pattern much better than the roundagon ones, but cant afford to be picky on my budget. 

Thanks again for all the input everyone.


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## hanknmorgan (Jan 19, 2006)

Just an update in case this helps anyone else later make a decision on brakes. I got 2 nice rides in last weekend and these brakes seem great. Installation and setup was straight forward. Power seems good already although I have read break in takes a while. I did a series of gradual downhill to heat them up and let them cool in cycles. They definately got stronger throughout the weekend. A huge difference compared to my old brakes. Definately much more grab already and much smoother and more predictable. Easy to adjust for no dragging and they seem quiet so far, but havent gotten them wet either. I think this setup will be more than sufficient for any riding that fits my ability anyway. I am not hardcore or anything. The price was fantastic as well. Got them from a forum sponsor cambriabikes. Highly recommend these brakes and this vendor to anyone looking for an upgrade to discs. Thanks again for the help everyone. Take it easy:thumbsup:


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## soccerdude (Aug 6, 2006)

I bought some 2008 BB7's a few months ago in 160/160 and I love them. They're a huge improvement over the old Hayes MX-3 maybe-stops that came standard on my bike. I do have a question though; if I wanted to upgrade to 185 in the front would I have to buy a whole new caliper kit with roter or could I just order a new, larger rotor and an adaptor? If an adaptor will do which one would I need?

Soccerdude


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## savagemann (Jan 14, 2008)

soccerdude said:


> I bought some 2008 BB7's a few months ago in 160/160 and I love them. They're a huge improvement over the old Hayes MX-3 maybe-stops that came standard on my bike. I do have a question though; if I wanted to upgrade to 185 in the front would I have to buy a whole new caliper kit with roter or could I just order a new, larger rotor and an adaptor? If an adaptor will do which one would I need?
> 
> Soccerdude


You just need a new rotor and an adapter. Which adapter depends on what type of fork you have. Does it have post mount? or IS mount? That will determine which adapter you need.


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## tatankainlondon (Apr 4, 2004)

I am 270lb
I run Formula Brakes (the One and Oro) 220mm front and 200mm rear but this is my DH bike setup and honestly I would probably be fine with 200/200.


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## Boyonabyke (Sep 5, 2007)

I'm 215, run Formula K18's with the sintered pads. We have some huge 4000ft down hills here in So Cal coming off the mountains. I run a 200mm front and rear. The 180's weren't enough, even with sintered pads. I much prefer the sintered pads, more modulation, stronger and less fade.


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