Disc brake mounting questions

Couldn't find anything on here about disc brake parts compatibility so here comes a few questions.

I've got an avid bb7 caliper with no mounting bracket and i want to put it on my kona p2 forks. what bits do need to do this and what size disc will i need to make it all work? I'm getting a bit confused with all the different options available.
this is to fit on a cheap shimano front hub, 6 hole disc mounting, think it's an xt. also will any standard brake cable fit the bb7, i'm guessing it will.

cheers for any advice, my bike knowledge has hit a rut!

i know nothing about disc brakes, but i think the caliper determines rotor size...i bought a shimano cable disc brake from retrobike, it came with a rotor. I bought a disc mount from wiggle (this may have also determined rotor size) and used an old bmx cable and a V brake lever. works a treat. x

The cable is standard all though many people say to get the most out of a bb7 you should use compressionless brake cable housing. Expensive. Never tried it so can't comment on how much better it is.

RE: Rotor size. You get a adapter depending on the fork and the rotor size you wish to use.

I think most forks do 160 mm without an adapter but 180 and 203 mm need an adapter, though I would not swear to it.

You can run either a 160 180 or 203mm rotor as long as you have the right size adaptor.
For the p2 fork you'll need a IS to post mount adaptor in whatever rotor size you decide to go with.

You can run either a 160 180 or 203mm rotor as long as you have the right size adaptor.
For the p2 fork you'll need a IS to post mount adaptor in whatever rotor size you decide to go with.

This^

The industry seems to be moving towards post mount fitting for both frame and forks. This looks like a good thing on the face of it (have'nt really thought much about it TBH). But most frames and forks come with IS mounts, so you'll need an adaptor.

This pic shows a IS to post adaptor.

If you want to run a 160mm front, you'll need one of these.
http://www.chainreactioncycles.com/Models.aspx?ModelID=20304
For a 185mm you'll need one of these.
http://www.chainreactioncycles.com/Models.aspx?ModelID=13721

I run 160 front and 140 rear. But thats a light weight handbag XC set-up. You may want to go to 185.

The 6 hole disc mounting is very standard so just pick the size rotor you want to run.

quality info guys, just what i needed. I'll see if i can find a cheap rotor in the classifieds and adaptor myself happy.

ah alas i've found my self another problem - bolts. I have none.

It's pretty obvious what bolts i need to attach the rotor but what do i need for caliper to adaptor and from adaptor to fork? will standard m5 bolts do it? the rotor ones all seem to be torck (or whatever the star shaped one is called) which is a bit of an arse.

they should come with the adaptor...my shimano ones did anyway.

I've got a avid 185 rotor you could have cheap, pm me if your interested

ah alas i've found my self another problem - bolts. I have none.

It's pretty obvious what bolts i need to attach the rotor but what do i need for caliper to adaptor and from adaptor to fork? will standard m5 bolts do it? the rotor ones all seem to be torck (or whatever the star shaped one is called) which is a bit of an arse.

I think they're M5, easy enough to source though.
http://www.chainreactioncycles.com/Categories.aspx?CategoryID=107&CurrentPageIndex=1[url="http://www.chainreactioncycles.com/Models.aspx?ModelID=20172"][/url]
Dunno why the rotors use torx, these are also pretty standard though.

Dunno why the rotors use torx

I can only presume its because the heads are so tiny they are more prone to rounding off

dont buy any bolt tills you get the mount/adapter, and the rotor bolted to the hub (yes torx, and yes so they dont round off, they get a lot of shit thrown at them where they are and you dont want to have to go down the route of hacksaw/angle grinding them off when the allen bolts you decided to dash in there get stuck and round off after one winter). you want to ba able to measure the whole set up so you dont get bolts that are too long and poke through and hit the rotor. obviously you can use spacers and washers but its nicer to do it without..

my lbs has a tin with loads of torx keys in. they do a lot of custom builds and you get another with every set of brakes you buy so i'd be suprised if your lbs wanted to charge you for one.

avid cable discs are amazing, ive used them for years. they can be a pickle to set up so the rotor doesnt rub (especially second hand slightly un true ones) but once its done they carry on nicely for ages. normal cable outer is fine, you'd be wasting money if you went for the posh stuff...

set it all up, loosen the bolts which hold tyhe caliper to the mount, squeeze the brake lever you'll see the caliper move and centre itself. do the bolts back up while still pulling the lever and you'll have a great place to start slight adjustment from. easy pie. i like to set the inside pad the closest it can be and then when the lever is pulled the outside pad moves and the disc hardly flexes at all. ace.

dont forget to GREASE ALL THE BOLTS - ROTOR TO HUB, MOUNT TO FORK, CALIPER TO MOUNT.... and if you get an option at the bike shop when you get your m5's dont get round head (dome head) ones, they are shitter and round easier and have no place anywhere on anything that goes outside...

dont handle the rotor with mucky hands, you'll get grease all over it - bad. if you have new pads they'll be shit for a while till they wear in (or if you do in fact manage to get the rotors mucky and transfer the muck to the pads). best way i have found to wear in pads is this....

steal one small can coke from a superstore of your choice. open. lie your bike on the ground outside, tip half can on the disc/rotor, and the caliper, making sure it goes on the pads too. leave it to dry a little, a few mins is fine. then put ear defenders on and go ride down a slope with your brakes on... squeeeeeeeak. it'll fade and the brakes will be much better. repeat with the other half can or dispose of the rest responsibly (do not drink).

the other method is more dirty and time consuming and involves smearing mud on the rotor. not sandy mud, nice muddy mud, like wet soil mud.

hope this helps..

cheers for the info, will be very useful. and yes i've heard its good to get a nice coating of "stolen" on all braking surfaces....

I've got a Shimano Alfine hub, and its got one of these type of disc brakes on the back, that mount with a lockring

So I needed to take it off, but accidentally ordered the wrong part from Chain Reaction, I got one of these which I am guessing is for a quick release hub with the rod sticking out of it.

The alfine hub has a fixed axle. Does anyone know what tool I need to get to take the lockring off?

I can see two options, one is the TL-LR20

and the other is the tl-lr10

I cant see any difference between them apart from the back bit, they both seem to have the same number of splines. Anyone able to help? I dont want to order the wrong tool again.

Thanks

That looks like the standard shimano cassette lockring tool?

If so I have one without the rod that you are welcome to borrow

park FR-5

That looks like the standard shimano cassette lockring tool?

If so I have one without the rod that you are welcome to borrow

I dont know - I've never used a cassette tool before.
But yes if you have one that would be great to use. Where are you based?

Actually I'll just PM you now...

Bit of a thread dredge, and possibly not the right place. i was wondering if anyone could point me in the right direction. I want to mount a disc brake on a v brake only fork. Now, before you tut and shake your head, It's something quite specific and I've seen it done, like this:

http://i.ebayimg.com/t/Proflex-mountain-bike-/00/s/MTIwMFgxNjAw/z/spsAAMXQgb1RLR~1/$(KGrHqV,!osFD+tlRuVJBRLR+1ZC-w~~60_12.JPG

I'm interested in a particular retro MTB fork, a Girvin Vector. The above image is of a mechanical disc brake retrofitted to said fork. I'd like to mount a hope M4.

Any thoughts? It looks custom, so not really sure.

Probably not custom just pretty old and very rare.

The above looks like a Hope mount and if I remember correctly they went with specific hubs.

Seen a few of the rear version with the torque arm that went up to the canti/v brake mount on ebay recently and they went for big money.

I think the other option would be to have something welded on like this:

http://3.bp.blogspot.com/-TMOspCPzEOo/TdiqilH4lEI/AAAAAAAAATM/YqvFu9Cga0w/s1600/IMG_2015.JPG

Ask over at retrobike...someone will have one.

I think the other option would be to have something welded on like this:

http://3.bp.blogspot.com/-TMOspCPzEOo/TdiqilH4lEI/AAAAAAAAATM/YqvFu9Cga0w/s1600/IMG_2015.JPG

I'm not sure how easy it is to spot weld stuff onto aluminium - you may need to get a whole leg fabricated.

Would of thought it could be welded, aluminium to aluminium? I'm not a welder so I have no clue! :)

Nah nor me, but I thought there might be a problem with heat treating or something, you don't get many repaired alu frames.

Ooh, I may have found something:

http://www.choppersus.com/store/product/307/Disc-Brake-Bracket-Billet/