mtnbud

I put together a harness to tie a stuff sack to my handlebars on my flat bar MTB and found it interfered with my brake handles. With cabin fever setting in, I made this bracket using 1 1/2" PVC. It holds everything solid, but I haven't tested it on a trail yet. Long term trail testing will be my next step to make sure the PVC holds up. I call it "The Unicorn 2.0"

cyccommute 

I foresee two problems. First, the load is going to be cantilevered out in front of the steering axis making the steering heavy and sluggish. With a load oriented parallel to the bars, the steering is already sluggish but putting it out like you have will exacerbate the problem.

Second, if you go over the bars...it happens...you'll find the horn in your chest or even in the face. It probably won't impale you but it gonna hurt.

mtnbud

I took it out for a short trial run today. I had my hammock, under quilt, top quilt, tarp, tree straps, and ridge line in a dry sack. There was a total of 9 pounds in the dry sack. Steering felt fine - might be different on a technical single track though. (I'll need to try that next.)

I didn't think about going over the handle bars and hitting the pipe. That could hurt! If I did go over the handle bars, it'd probably snap the PVC too. On the other hand, I could add a sharp point to the end to deter Sasquatch and rogue gazelles:

TimothyH

You could use it to hunt.

Sasquatch Bar-b-que.

tyrion

Make it into a flamethrower!!!!

mtnbud

I like the suggestions! Harvest it and then cook it with the flame thrower!

(There's a new law on the books in Oregon that states you may salvage the meat if you accidentally hit and kill a deer or elk with your vehicle. I'm not sure if a bicycle counts. It has be an accident too...)

rseeker

Cool concept. How did you get the PVC to open up and straddle the stem? Did you soften it with something like a blowtorch? (I'm assuming the whole piece began life as a typical PVC pipe...)

mtnbud

Yep! - Pretty much so! It was a section of 1 1/2 " schedule 40.

I used a hole saw for the curved gap for the handlebars and cut a seam from the edge to the gap. I used a heat gun to soften the PVC then molded it flat one side at a time. It worked, but scorched the PVC a bit due to a lack of me being patient. I was a bit sloppy on my edges. I finished up a crude model and mounted it to see if it was worth doing a nicer job.


I decided it was worth doing a better job so I used my outdoor tank top propane heater for the second version and was able to heat the PVC more gradually and evenly. I also used a flat piece of metal and a flat table top to get the edges more flat and even.

saddlesores

how does pvc react to uv? does it degrade, crack or become brittle?


did you use sch80? i think that's the type for hot water. will the reg'lar pvc lose strength and start to bend (with 9 pounds attached) if in direct sunlight for an extended period?

CliffordK

One thing I discovered on my old Colnago was that I had a bar mount bag hanging straight down. It wore through the front logo on the head-tube within a year or so.

So, now I have a cover with a worn rust spot in the middle.

Overall, it may not hurt anything, but if you have a bag resting on the head tube, you'll get wear on the head tube, and perhaps the bag.

Happy Feet

While at first glance it looks sort of simplistic I have to say bravo on trying something new!

It really isn't that far off from the now accepted seat post racks that stick out the back end. There are some issues but it also solves one potential problem of clearing the hoods using a sideways drybag. Some more work on the prototype might product an Al even CF post painted the same as the stem that was easy to put on/take off with channels to hold the straps more securely. That could actually be a marketable cheap removable alternative to HB rolls. I would keep it shorter rather than longer to avoid excessive cantilever balance issues and load the drybag with lighter stuff. I might even give making one a go as a project.

I have aero bars on one bike and the space there is sometimes used by tri athletes to mount a largish water tank instead of using water bottles so the idea is not totally crazy: https://www.probikekit.ca/cycling-accessories/profile-design-fc35-drink-system/11674443.html?affil=thggpsad&switchcurrency=CAD&shippingcountry=CA&variation=11674445&&thg_ppc_campa ign=71700000013092926&gclid=CjwKCAiA7vTiBRAqEiwA4NTO6zIDaaTKJFz7C3rSmPN-GbHHaDQLrYOHjKUGyuIGJ53z-2MMzh5yABoCGMsQAvD_BwE&gclsrc=aw.ds


On a trip I did something similar by strapping my sleeping mat between the aeros. It looks goofy but I found it functional as I could just hold the bag instead of the bars. I would play it like a bongo drum to while away the hours...

mtnbud

Thanks for everyone's input. I like to tinker and it's fun to get your thoughts.

I'm not planning on making this for anyone other than myself, so anyone who wants to play with this idea is welcome to it at their own risk. I do wonder about how well the PVC will hold up over time. UV light may degrade the PVC - I could paint it. PVC is also brittle under extreme cold. I had a small piece schedule 40 in my shop. I'm not sure how available 1 1/2" schedule 80 is, but it would be stronger. It would probably be tougher to mold with heat.

I decided to use a simple dry bag rather than my homemade harness. It looked cleaner, but I am concerned about the bag rubbing on my top tube - both that it'll wear the paint on my bike and possibly wear the dry bag. My bike is aluminum so I think it wouldwouldb't be too big a deal - wearing a hole in the dry bag would be a bummer. I certainly wouldn't want to put too much weight in it, or extend it out too far.

I thought about issues with a marketable product. Using something other than PVC would make sense. Carbonfiber or another strong molded material would be awesome. There may be isses with too many variations between differing stem and handlebar combinations. I'd also assume you couldn't do this with a CF stem or bar.

Tourist in MSN

Schedule 80 is thicker than Schedule 40. The difference is only in dimensions, not material.

CPVC is better for hotter applications that PVC, but you are less likely to find it in a hardware store.

I would expect that PVC would eventually fail from the vibration. If your handlebars are of a diameter that would allow a bar end grip to be mounted closer to the stem, you could use a couple bar ends instead of the PVC pipe, but they would likely be shorter. Just a thought.

mtnbud

Good idea!

Happy and Tourist - Your comments made think about putting a tri-bar on a mountainbike. Might be a better looking and secure system. I found this image on a websearch:
https://chrisaldgate.wordpress.com/2...r-saddle-bags/

TimothyH

I'd back the kickstarter for a CF version.