Rear carrier with 4 point mount

[Paul_Bags]

Hi, I've been looking at getting a rear carrier but I'm confused by something: I understand where the bottom stays bolt on, and I understand seatpost clamps, what I don't understand is where the other 2 points bolt on in a 4 point mount carrier? Do they go on the seatpost clamp? Or am I supposed to drill holes in my frame?
And the ambiguity of names annoys me, I try searching for 'carrier' and I get a rack for a car. Seems however i word it, I get some sort of a rack for a car.

[Skyguy9999]

For a 4-point mount bicycle rack, the top two points go into the frame. This guy installs one in a video here: http://www.expertvillage.com/video/4835_rear-rack-bicycle.htm

Now the question really becomes what your bike was designed to take. Sometimes all you can get away with are 2 pt seatpost mounts. Much of what you can buy for a bicycle rack depends on the design of your bike.

You might be able to post pictures and allow us to see what kind of bike you have, where acceptable mount points might be (you'll either find two as in the video, one in the center of the forks on a cross-bar, or none at all), and maybe even address your drilling question. Of course, drilling holes in your particular frame might not be wise at all, so bear that thought in mind when you consider things.

[Paul_Bags]

Heres some photos: http://s675.photobucket.com/albums/vv119/Paul_Bags/

I have "one in the center of the forks on a cross-bar", but I haven't seen any carriers designed to mount to it. I also have disc brakes. What I really want to do is mount a big lockable box to the rear of my bike, and I've considered mounting it directly, but I don't really have the tools or the skills so I was looking for a carrier is a means to and end. I still haven't found a suitable box yet.

Oh and I'm not drilling into the frame, I can't really afford to replace it.

I found a box, added some photos. It's not as big as I was looking for, it holds all my gear but I couldn't really do light shopping as well. Still, I might be able to store some lightweight panniers in it as well for when I do go shopping.

[DaveM]

Most standard bike racks will have a couple holes in the center to take a single upper mount like your frame is designed for. (ex: MTN-1 rack at http://www.blackburndesign.com/racks.html) Or do two mounts to the seat post clamp if they'll reach. Most of the weight goes to the lower mounts so that's where you want a good solid attachment.

"Carrier" does usually refer to a car carrier. Try searching for "rear bicycle rack".

I also recommend the bikehacks.com site for some cool DIY designs.

[Paul_Bags]

If I may settle in, I point you to the last 2 paragraphs

I bought a giant brand rear rack and got the adapters for it, in a fit of misplaced optimism. In my haste I saw the picture for it and thought 'that looks good, I'll take that', the store I bought it from implied it came with the adapters (it didn't, but they gave me them for free when I complained), however it didn't come with the seatpost clamp for mounting and something tells me I can't get it here without ordering overseas, it fact it looks like the company that supplies my country with giant branded accessories has changed and they didn't actually order anything at the start of the year... I did however figure out that, because of their design, I can mount the two top stays to the one mount point on the cross bar if I buy a longer bolt to go through them, which I did.

So then, on to my problem. The disc brakes that came with my bike are the ball bearing type with an arm sticking out that gets pulled up and forward by the cable when the lever is pulled. With the current adapters attached to my new rack the bottom stays only clear about one third of the arms reach, about 25mm. I've already looked at the possibility of a new brake adapter, it simply wouldn't be able to move the brake around far enough for the stays to clear before the brake itself is blocked by the frame. On the up side I now understand how my brake works inside and out, but I'm a little fuzzy on the putting-back-together-and-readjusting ;p. (it's ok, I prefer my rear brakes a little less responsive anyway, and I can still squeeze them to a lock in short order if needed)

It seems that besides getting a different rack I have 2 options:

A) find 2 pieces of metal long and strong enough to bolt in 2 or more places to the adapters (adding without the adapters would allow for rotational movement under load)
B) Replace my brake with something that would provide more clearance, ether a mechanical with a 10mm or less length arm, or a hydraulic. (cannot fit any other style brakes to my frame).

(A) sounds cheaper, (B) sounds safer. I guess my questions are: can I get a mechanical disc brake with such a small actuating arm? are hydraulic brakes worth it on a bike used mainly for commuting/grocery shopping, with the occasional around town blat and even less frequent off road session, when all I really want to do is fit a rack to my bike? Do they function better in the wet? If they do work better in the wet/cold than mechanical, then that could be a plus for me as my bike is my only transport to and from work, coming up to the rainy season. However being more difficult to repair esp. when out and about is a major con for me for the same reason, esp. since I ride solo even when riding recreationally.

Now if you didn't just go 'tl;dr', then I probably owe you a beer, but that's not happening :p.

[keithmo]

This may not help much (since you've already bought a rack), but the Old Man Mountain racks (http://www.oldmanmountain.com ) work very well on disc brake equipped bikes. I've had one on my Stumpjumper for about a year, and I just put on on my wife's Stumpjumper.

Installation on my wife's bike was much easier than on my bike; her bike originally came with rim brakes, and therefore the frame has the caliper mounting points. The OMM racks can use these. My bike, on other hand, is disc brake only, so it has no caliper mounting points. I had to use p-clips to attach the rack to the seat stays. It took a little trial & error to find the correct p-clip size, but other than that installation was a breeze.

(I mention this because from the photos it looks like your bike is disc only, and will therefore require p-clips for an OMM rack.)

Again, this may not be an option since you've already purchased a rack, but I'm throwing this out "FYI".

[Paul_Bags]

Those are some nice racks, bit expensive for me though. I have square seat stays and no V brake bosses, so that doesn't help much through.

I'm going to upload 2 more photos, one that shows the adapters falling short of their mounts, and one that shows where I intend to mount the upper stays on the cross bar.