# Post mount adapter? 160mm to 180mm



## pocketdrummer (Jun 2, 2009)

I'm just now getting into this, so I'm not very knowledgeable just yet. I currently have 160mm rotors on a Manitou Black Super Air Fork. The current rotors (looks like the regular Hayes rotors) are a bit bent. So much so that I can turn the wheel gently and the rotor will come in contact with the pad and stop the wheel.

I heard that it is a good idea to put a larger rotor up front (due to the weight distribution during braking). So, I figured I'd go with a 180mm rotor for the replacement. The only problem is that I'm not sure exactly how to do that.

There are two rotors I'm looking at, the first is the Avid G3 Clean Sweep Rotor, and the second is a Formula K24 Rotor (that comes with the adapter).

Do I just need a 160mm to 180mm post adapter to upgrade to a larger rotor or are there other things involved too?

Also, are there disadvantages to having a larger rotor other than weight? Which rotor is better? etc.

Any information helps


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## JimC. (Dec 30, 2003)

*thoughts...*

1) read the disc brake FAQ upper right in the Brakes forum. You can easily fix a warped rotor in 3 minutes.

2) new rotors and adaptors are a minefield. You need to really know what you're doing, and if the fork will take the increased leverage of a larger rotor. so check the fork 1st to see what size it will support, then find the place to buy the bigger one and let them tell you what parts you need.

Jim


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## pocketdrummer (Jun 2, 2009)

JimC. said:


> 1) read the disc brake FAQ upper right in the Brakes forum. You can easily fix a warped rotor in 3 minutes.
> 
> 2) new rotors and adaptors are a minefield. You need to really know what you're doing, and if the fork will take the increased leverage of a larger rotor. so check the fork 1st to see what size it will support, then find the place to buy the bigger one and let them tell you what parts you need.
> 
> Jim


When I had the bike repaired (bottom bracket, front brake seized) he tried to true the rotor as much as he could. The result is that it is still rubbing on the pad when I spin the wheel. I don't know if I'll be able to do better than the mechanic.

Also, the manual for the fork doesn't say much of anything about the disc. It only says there's a disc only version. (I searched the PDF for disc and rotor and that's all I found.)

I don't usually ask questions on forums unless I've tried something on my own first.


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## Takedown (Jun 28, 2008)

What fork do you have?

What brake set?

Take a look at this rotor as well, I really like how they perform:

http://www.pricepoint.com/detail/16...Disc/Alligator-Serration-Disc-Brake-Rotor.htm


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## pocketdrummer (Jun 2, 2009)

Takedown said:


> What fork do you have?
> 
> What brake set?
> 
> ...


The fork is a Manitou Black Super Air (has a 120mm sticker on it, but the model that comes with this bike is supposed to be 100mm if I'm not mistaken)

The brakes are Hayes HFX-9 Hydraulics.


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## JimC. (Dec 30, 2003)

*then this should work*

I stress "should"...

a post mount adaptor for the larger rotor from Hayes hfx brakes should fit the standard post mount.

It appears there is no offering for the Black series in anything more than 6" though.

good luck, Jim

http://www.hayesdiscbrake.com/product_af_brackets.shtml

& check this too...

http://www.hayesdiscbrake.com/pdf/Mount_Bracket_Chart_2005.pdf


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## pocketdrummer (Jun 2, 2009)

JimC. said:


> I stress "should"...
> 
> a post mount adaptor for the larger rotor from Hayes hfx brakes should fit the standard post mount.
> 
> ...


hmm.... for some reason those links aren't working :-/


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## JimC. (Dec 30, 2003)

*then use google*

and search under hayes hfx adapters. jc


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## pocketdrummer (Jun 2, 2009)

JimC. said:


> and search under hayes hfx adapters. jc


So, they aren't universal? I would have to find an adapter specific to Hayes brakes?


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## pocketdrummer (Jun 2, 2009)

Manitou tech support got back to me and said it supports up to 7". I guess it's a good thing my heart wasn't set on the 8" one  

So, now that I got that out of the way, I just need to figure out which adapter will work.


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## JimC. (Dec 30, 2003)

*no*



pocketdrummer said:


> So, they aren't universal? I would have to find an adapter specific to Hayes brakes?


I just used that as an example. jc


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## pocketdrummer (Jun 2, 2009)

JimC. said:


> I just used that as an example. jc


Sorry, I'm just trying to get a hang of this. So, if the fork supports a 180mm rotor and the one I'm looking at comes with a 180mm adapter, then it should be compatible? Or should I just order it, take it to the mechanic, and have him figure out what adapter to use?


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## JimC. (Dec 30, 2003)

*Let's start over here...*

1) you've got a Manitou Black Super Air Fork

2) I don't know how big a rotor it will take ( larger forces can wreck forks not made to take the leverage)

3) If you choose, say Formula, or Hope brakes or whatever, then you need only get the post mount adaptor _for that specific brakeset_, and then install it.

You should be fine, but it's worth a quick check to ensure that the fork can take the forces of the larger rotor. If in doubt, a 7 inch rotor should more that stop you, 8" is usually for DH applications.

Good luck, Jim


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## pocketdrummer (Jun 2, 2009)

JimC. said:


> 1) you've got a Manitou Black Super Air Fork
> 
> 2) I don't know how big a rotor it will take ( larger forces can wreck forks not made to take the leverage)
> 
> ...


I checked with manitou and it supports up to 7". I found a Hayes adapter that is for a 7" rotor. Now I just need to decide on a rotor. I looked at a few others, but I haven't quite found one I can settle on. I'm not too worried about weight, but Im looking for something that will take a punishment and perform well. Any suggestions?

Oh, and what does a titanium coating do for rotors?

(thanks for your help thus far, I really appreciate it)


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## JimC. (Dec 30, 2003)

*I suggest that*

if you get a Hayes adaptor, you stick with Hayes Brakes. Stay within the product line; mixing and matching parts can leave you frustrated if things are not quite lined up.

Choose the brake you want, the 7 inch rotor, and the post adaptor for that brakeset. Personally, I would 
1) choose the brake you want and 
2)the shop or mail order you wish to use, 
3)then call them and walk them through your needs, ensuring you get all the parts.

Some mail order houses make it a minefield to order; they offer the brakeset, but not the rotor or adaptor. So take your time, and you'll nail it. Lastly, while more costly, your LBS might be the best place...have them quote you on a 7" front and $ to install it, and set it up. More $, but less hassle and pain if a mail order set gives you headaches installing it or is missing parts.

Hope that helps. Any more specifics and you should move over to the brakes forum, I'm a generalist, not an expert.

Jim


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