[Jackal]

Hey guys I have a set of Hayes hydro calipers on my 2004 Banshee Scratch. The front is the Red/White/Blue "Freedom Ride" 9-11 edition. They came with 6" rotors. My 2002 Z1 and my 2003 DJ2 forks are QR20+...made for 8" rotors.

Before I got my DJ's, I was running the Z1's. I had the appropriate Hayes adapter for the 6" rotor conversion...74-29D. Well, in order to get the caliper to clear the rotor I had to use the washers that are suppose to be used on the bolts that secure the rotor to the adapter, as spacers between the Hayes adapter and the fork mounts. This worked perfectly, but I had very little threads in the adapter when it was all said and done. When I finally got the DJ's, I moved everything over and had the same issue.

I called Hayes and they said I had the appropriate adapter, and that I would probably have to leave it spaced as it is, and I would need longer bolts for the adapter, as this is the area that takes most of the stress. They sent the bolts out that day. Well, I decided that I'd prefer to have the appropriate setup, so I ordered an 8" rotor, and the EXACT part number'd Hayes adapter specific to my fork / caliper combo.

All of my parts arrived yesterday, including the longer Hayes bolts. I installed the new rotor and adapter and guess what...SAME ISSUE!!! I had to go to the hardware store and get the thinnest stainless washers I could find that fit the 6mm bolts to run between the adapter and the fork mounts. I used the longer bolts from Hayes. I also had to get a chain saw file and file out the slots in the caliper itself to allow for more adjustment to clear the rotor.

I sold the Z1's to my uncle so he could build up his 2004 Surly Instigator. He got a set of Hayes mechanical disc calipers. When we went to install his front caliper we had the same issue, using a 74-20D adapter. Well, this adapter is for 6" specific QR20 dropouts, so I gave him my 74-29D conversion adapter and it worked PERFECTLY!!! Something has to be nutty with my front caliper. Why did I have these issues? Does it sound like my current setup is fairly capible?

Another quick question...my buddy / bike mechanic helped me replace the front brake hose with a braided Hayes hose. We pulled the pads and bottomed out the pistons in the caliper and proceeded to bleed. When I put the freshly bled assembly back on the bike yesterday, it seems like the pads retract too far away from the rotor so I don't have quite as sensitive of a brake lever. The rear 6" seems way more powerful than the front 8". Do I need to bleed again now that the pads are in and closer together? My buddy says he has always done it the way we did and that is how it is suppose to be done. Thoughts?

I wish I'd have gone with mechs. Thanks!!!

 

[madbob]

I had the same adapter problem when I bought my Rocky Mountain Flow. It came witha DJIII. the adapter was about 7/16" wide. When I put a DJII with the QR20 I had to change the adapter to one that is about 5/8" thick. the profile is the same, but the width is a critical differance. I wish I had part number to help but I don't your LBS should be able to take care of you if you take your adapter in and tell them you need the wider one.

As far as the front brake not feeling right. it takes time to break in a new rotor. give it a few days, and a handful of hard aggressive stops to break it in and all should be well.

 

[Repack]

I did not read much of the above, but here goes.
Both forks should have 51mm tabs. When looking at the forks from the side, they will be in the same positiuon relative to the axle. Forks designed for 8" rotors have the tabs spaced out further from the centerline of the fork to allow for a thicker/stiffer adapter to deal with the extra forces of an 8" rotor.
All you need to ask for is a Hayes 20mm fork adapter. Mention that its for an 8" rotor. I think that Hayes may have started selling a 6" adapter for 20mm forks.

 

[SKYWAYBUZZ]

If you pull the front wheel and hit the lever w/o a rotor the pads will go out more. Don't pull the lever to hard, watch and see the pads extend just a hair more than they were.

 

[hardtailer88]

I think that I had the same or a very similar problem with an xc bike of mine when I installed hayes hfx-9s. There wasnt enough space for the caliper to clear the rotor. I called up hayes and they said that the drillings in the caliper were wrong and sent me a new pair for free... which still had the wrong drillings!!!!!!!!!! I took it from there and drilled the holes in the caliper wider. This worked. Unfortunately I dont remember the exact caliper hole measurements.