Brake Calliper Problem
 

Hi all, bit of a newbie so go easy on me lol. Looking to buy some rigid forks for my mountain bike and ive got my eye on a set. However ive noticed the mounting bolt holes for the brake calliper face into the bike. I have Avid Juicy 3 brakes and on the current forks they are in-line with the bike e.g. 90 degrees different to the rigid forks. How do you go about mounting the calliper onto these new forks.

Any help gratefully received

Thanks

r10ley

You probably need to find a rigid mtn bike fork that has "cantilever brake bosses" that are brazed or welded on properly. The type of fork you are probably looking at is a "beach cruiser fork" that is designed for a caliper brake that uses a center-bolt through base the fork crown. Don't mount a caliper to the front fork. Get the correct fork with cantilever (compatible with linear pull - aka V-brake) and the design should be self-evident.

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The OP isn't asking about V-type or Canti brakes but Discs, what the OP appears to have is POST mount Avid Juicy 3's and the new rigid fork has an IS (International Standard) mount, all the OP needs to do, is get the correct adaptor, availiable from places which sell Avid brakes, to take the mount from IS to Post.

For the OP, there are several other factor to look at when changing forks, steerer size, fork length etc, make sure what you are looking at is compatiable with your current frame

Sorry. I didn't think or read completely. Should have seen the Juicy 3 reference. Don't get a canti-fork. If you have rigid fork with standard disc brake mount, keep it.

My bad.

But, I'm still confused. Question for the OP: Were the AJC3 brakes mounted in another fork before? The caliper bracket typically bolts perpendicularly into the fork or frame using machine bolts. The caliper assembly then bolts on with a different set of screws to the bracket. Was there only one set of mounting bolts and no separate adaptor bracket for your AJC3 brakes?

Thanks
 

Hi all thanks for your input, being a newbie my description probably wasnt the best : ? After further investigation it turns out I do indeed need a fork mounted to IS adapter for these particular forks. When you say there are other things to consider such as fork length, how do I go about measuring the current forks so I can buy the correct type?

Thanks all for your help

r10ley

Sorry didnt read last question. Currently my front avid juicy brakes bolt straight into the frame without a mounting bracket. The threaded holes in the forks are in-line with the bike unlike the new forks where the threaded holes face into the bike (which I believe is IS mounting).

Thanks

r10ley

The OP (probably) have a sus fork which he wants to replace with a rigid fork. The majority of sus forks of reasonably recent origin use Post Mount, with two stubs facing rearwards. For 160 mm rotors the caliper can be bolter right on w/o any intermediate bracket. Bigger rotors require a bracket.
Rigid forks OTOH seems to favor the older IS Mount, which is what you are describing.

To the OP:
Yes, you need an adapter/mounting bracket for IS mount + the size of rotor you're planning to use, and maybe particular for your brand of brake as well.

The measurements needed:
1) axle-to crown. Easiest is to do this with a pal. Get on the bike, allow your weight to compress the fork to some sort of average riding height. Measure as well as possible the distance between center-of-wheel-axle and where the crown race sits(just to the underside of the lowest part of your headset). The more the axle-to-crown of the fork you pick differs from this value, the more the handling of the bike will change.
Me, I'm not very sensitive to these changes and quickly stop thinking about them, others are apparently more finicky. Failing to hit spot on is no big deal.
2) you've gotta get the right steerer tube diameter.
3) if you're buying used, you've gotta have enough steerer tube length.
4) when switching forks on road bikes, people often talk about rake as well, but I don't think I've ever seen it mentioned for MTBs.