Tricks of the trade when mounting a computer

[razor_USMC]

I have had a Cateye in the past, and just mounting it to the fork was easy enough to do cleanly, but I am now getting a Astrale 8 with cadence. It is a wired version that needs to make its way to the crank. I am getting a new bike next week and was wondering if anyone had some tasteful ideas of how to cleanly bring the wire and parts along the frame without looking too ghetto. I dont want my brand new Orbea to have all these wires and quickstrap parts junking it all up. And I especially dont want to affect the performance of the cables either. Anyone as anal as me about keeping your bike looking good and getting the job accomplished cleanly at the same time?
Any tricks of the trade that you have used besides just the quickstraps provided?? Thanks in advance.

 

[SpearSlinger1]

Mine's a CycloMaster CM213C. What I did was to position the sensors (both on left chainstay) and magnets first, ensuring I had plenty of cable to make it to the 'bars with suitable slack then zip-tied the cables to the top of the chainstay and down tube. I ran the cable on top of the tubes to protect it from any road debris that might be kicked up by the tires. The 'puter is mounted to the bars to the left of the stem primarily because at the time I mounted it the GPS was still mounted to the stem with zip-ties, duct tape and an old sock for a shock pad. I want to leave the stem open because the GPS may be going back on there here in the next couple weeks. This probably isn't the prettiest way to go about it, but for me it doesn't matter how it looks, the beauty is in the functioning.

 

[Savant]

I just put on an Astrale 8 myself. While I'm no bike expert, I am an old hat at electrical/electronics. For the run I used heat-shrink tubing to secure the computer wire to the cable that runs from the rear shifter to the rear gears. By doing this I was able to avoid having any cable ties on the run up until I reached the first sensor. When the heat shrink is used (and shrunk) the size of the cable isn't much bigger than it was before, so you can use your existing cable stays to secure it.

A few considerations to keep in mind if you are thinking about using it. First off you need to make sure that the sensors (without the mounting bits) will fit through the unshrinked tubing. Next, you also need to remember that there may be some small printing on the heat shrink, so it may not be a perfect black finish. (other colours are available in limited circumstances if you don't use black on the bike - if you have aluminum cables then you may be out of luck since they don't make 'clear' in the big sizes) Lastly, heat shrink tubing uses heat, which can damage components if not careful. Just remember that HEAT shrinks the tubing, not flame. So if you don't use a heat gun, make sure to keep any flames away from the tubing itself.

You want to look for "non-adhesive flexible Polyolefin Heat Shrink Tubing" which is flexible and resistant to abrasion. I'd suggest a ratio of perhaps 4:1, 5:1 or 6:1, which means it starts off 4, 5 or 6 times bigger than what it ends up at when you heat it. (you need a big opening since you need to pass the sensors through it, I'm sure you don't want to do any splicing ) So a 4:1, 5:1 or 6:1 should allow the sensors to pass without problem while still shrinking snug to the shift cable. (I don't know what I used since it was stuff I had lying around and there were no markings on it - 3:1 will likely be too small though)

For example, a piece of 4:1 heat shrink tubing with a pre-heat opening of 1" will shrink to 1/4" when heated. When buying heat shrink you will want to measure the diameter of your cable sleeve, and then buy heat shrink that will shrink to an INSIDE diameter of about that amount. (which means it will be snug when the computer wire is alongside it.) Don't worry about the heat shrink cauing issues with shifting since the heat shrink cable doesn't have 'compressive' qualities that could cause problems. IOW, it shrinks, but it won't crush your cable since heating makes the heat-shrink soft and flexible.

Here's a place that sells oversized 4:1 in 4 foot lengths. (check the picture of the purple stuff to see what it loks like before and after) The bigger stuff isn't cheap, but if you want a clean job without cable wraps, this is a good alternative. I can't remember how big the sensors are, and that is what will determine the size you need. Measure those first and keep in mind that you need a bit bigger to allow them to slip through easily.

Just my thoughts on this anyway...

Regards,

Savant

 

[razor_USMC]

FANTASTIC! This is JUST what I was looking for. Did you have to pull the brake calbe out of its "clamps/holder" to do it and then put it back? I am just wondering if it will still fit.If I don't have a heat gun will a hairdryer be hot enough? Probably not, huh? If not, where can I rent a heat gun? Don't mean to sound cheap but I doubt I will do enough shrinking around the house to necessitate the purchase, but if I have to, so be it. Do you think that Radio shack in the US will have the shrink cable? Fantastic idea, thanks for your reply.

 

[Brunswick_kate]

FANTASTIC! This is JUST what I was looking for. Did you have to pull the brake calbe out of its "clamps/holder" to do it and then put it back? I am just wondering if it will still fit.If I don't have a heat gun will a hairdryer be hot enough? Probably not, huh? If not, where can I rent a heat gun? Don't mean to sound cheap but I doubt I will do enough shrinking around the house to necessitate the purchase, but if I have to, so be it. Do you think that Radio shack in the US will have the shrink cable? Fantastic idea, thanks for your reply.

Razor..any shrink wrap I've used it needs very little heat. A blowdryer puts a fair amount of heat out. Too much heat is usually counter-productive and heat guns are tricky with the amount of heat they put out.

 

[Savant]

I usually use a heat gun not because you need high heat, but because you need CONSISTENT and FOCUSED heat. A hairdryer can do as well, just try the lower setting first to make sure that you don't melt the heat shrink. You can use a propane torch (for plumbing) too, but you need to be VERY careful since flame can easily melt the heat shrink. (not to mention the stuff inside of it) I'd say you could use a hairdryer and just see how it goes. (make sure to heat from ALL sides evenly to get a good shrink)

For the most part you won't find this heat shrink at Radio Shack. They will have heat shrink, but usually only 6" pieces and they won't have the over-stretch stuff that will shrink a significant amount. The ratio is what you need to pay attention to.

If you are doing this, then first thing first, measure one of the sensors at the end of the cable. (since this is where you will slip on the shrink) Keep in mind that you need to take the width into account as well. If you have an old bike tube lying around that you can cut up, cut a piece and roll it into a smaller tube shape, but make it big enough to fit the sensor. Once you have that made, measure the diameter of the opening with the tube as circular as possible. (since they measure this stuff the same was as a pipe, inside diameter of a perfectly round opening) You don't need to keep the opening circular to fit the sensor through, just to measure it. You can distort the shape of the tube any way you like so long as the sensor will fit without getting caught.

Once you figure out the size of opening you need, divide that by the size of the cable sheath that you have. So if the sensor needs a 1" opening and the cable sheath is 1/4" in size, then you need 4:1 ratio heat shrink with a 1" expanded I.D. (inside diameter) and a 1/4" recovered I.D. Also note the heat shrink will shrink as it cools as well as when heat is applied, so don't over aplly heat to get it smaller if it won't go. Let it cool and contract naturally.

As for where to buy, that depends on where you live. If you are in a big city, check your yellow pages for electronic stores and call to see if they have it. Make sure to know what you want since they may not understand what you're using it for. (it's not a standard application as you can expect ) If not then the link I gave you has some as well there are LOADS of places on the net if you put 'heat shrink' into Google.

To install you will need to disconnect your gear cable, but you won't need to de-sheath it or anything. Just disconnect it and pass it through the heat shrink after you get the sensors and wires through. Use twist ties at both ends to hold the wires and cable in place temporarily, then heat the shrink. (while it is still OFF the bike) When done, let cool and mount back to bike.

I hope this helps.

Regards,

Savant

 

[razor_USMC]

Very clever and I appreciate your input. I'll give 'er a try. I guess they don't call you Savant for nothing.

Regards.

 

[Savant]

I'm just glad I have something to contribute in the forums. I haven't ridden in years and I'm just getting back into it, however while i'm not a bike expert, I do know electrical/electronics.

I guess it comes as no surprize that when I ws in my early teens I had my '10 speed' (that's gonna give away my age) and it was fully wired up with headlights, tail-lights, turn-signals, all attached to a latern battery on the rear rack. Damn those were some geeky times...

Regards,

Savant

 

[wyllisx2]

Sheesh Razor it's just a comp held in place like ties!!!! If you are that concerned go wireless.

 

[razor_USMC]

I know what it is, thanks for your 0.02 cents. Wireless is less dependable and has 1/2 the battery life. I know guys who hit a hard bump and lost EVERYTHING on their wireless. I just didn't want my wired version to look half-baked and thrown-on like so many do. There is, and isn't a way to do things... and some of you just don't get it.

 

[wyllisx2]

I guess I must be showing my lack of style . 1/2 baked 1/4 baked or raw, whatever. I have the wires running down my tubes & no-one has ever noticed or said anything. Maybe they just hold back & are polite. Perhaps they noticed I'd rather ride than look good, I don't look that good btw.

I just ride & watch my Cateye 8 for info. Great comp too boot.

Shrink wrap the hell out of it & maybe your tubes will stay clean too!

 

[razor_USMC]

Touche'. I actually laughed out loud on that one.