I need the 2 mounting clamps-to-bicycle seat post. Where can I get these

That tube is the seat post. Without the proper clamp, you're screwed. Contact local bike shop for assistance

Never drill holes in a bike frame unless you have a death wish. "Rand 18-speed" doesn't tell us much. Most cheapo bike frames have a 'brake bridge' with a hole on the center for mounting accessories like fenders. Many racks can mount with a single rather than double front supports.. Lacking that, call a bike shop or web search for "bicycle seatstay rack clamps" to adapt the rack to attach to the seat stays.

Sunlite also makes a seatpost rack mount http://www.bikebagshop.com/sunlite-rack-mount-seat-post-clamp-p-1146.html?gdftrk=gdfV22203_a_7c1316_a_7c5544_a_7c11461678151 which looks like a more elegant way to solve the problem.

All you need to do is match the seat post clamp to the seat rails. 99% of seats are compatible with modern days seat posts. If yours doesn't fit, get the adjuster.

loosen seat post clamp with correct size allen. once its loose push down and twist the seat untill its where you want it then tighten the seat post clamp

A typical seat post will have a tapered end that slips into the seat clamp which grips the post and clamps the seat rails, all at the same time. If the seat post is not tapered at one end, then it must be a 22.2mm post. Loosen the seat clamp's nuts enough to install the saddle rails. The clamping area for the post should be under the "nose" of the seat. It should loosen enough to slip over the post without falling apart. Otherwise, you may have mis-matched parts.

• The seat connects to the seat post and the seat post inserts into the seat tube
• you will have to first loosen the seatpost clamp located where the seat tube meets the seat post.
• after loosening, you should be able to raise the seat to your desired height, just don't forget to tighten teh seatpost clamp.

I have a feeling it is made for old style bikes, not these new fangled things. The seat post clamp is the bolt , nut or quick release that holds the seat in the tube and stops it from going up, down or spinning. In the case of the new bike, it could be way down low, where it won't do you any good. I would suggest a clamp of some sort up top to make the child's seat sit level. Depending on how the child's seat is fastened on, you will have to make something work. Like a pipe clamp, antennae clamp, muffler clamp, something like that to replace the seat clamp. But iof you seat clamp is level or up high, remove the nut and bolt and see what happens with the child's seat clamp. Hope this helps.

never exceed safety line on seat post. flip the seat post bracket pointing forward then insert post ...tighten both seat clamp bolts evenly exposing close to equal exposed threads on both sides these seat bolts will snap if over torqued.
now make sure the seat post clamp is not riding above the top of the split..you never get it properly tight. again dont over torque these bolts you might crush the tube. Now see if it secure and doesnt have any play. to get proper height have the person set on the seat and have pedal at the full bottom position their knee show not be fully extended you should have the knees slight bent.

If you are looking for instructions on how to mount the seat onto your seat post, it is a straightforward, easy install. If you are asking how to actually use the seat, that is also very easy to explain. Can you please clarify what you specifically need instructions for. Bicycle seats do not usually come with instructions, as one can see how to install a seat by simply removing the old seat. If you use an adjustable wrench, or alternately an open ended wrench to remove the existing seat, you can easily install the new seat yourself. Be sure to firmly tighten the rail clamps underneath the seat (using the bolt that is inserted through the u-shaped seat post clamp) so there is no shifting of the seat while riding. If you need additional information, please write back.

Thank you for using FixYa.

The top should anchor to the seat post bolt, the bottom two should clamp onto the rear triangle. you should have the seat, a spoke guard, two clamps, and seat post bolt mounting bracket. if you received all the pieces. Hope this is of some help. Ed