Showing posts with label maintenance. Show all posts
Showing posts with label maintenance. Show all posts

Friday, August 03, 2007

1979 Free Spirit Ten Speed


Once I started riding this old Free Spirit ten-speed, I was hooked. Most of my riding is on a paved recreational trail, so the thin tires aren't a hazard and the bike is a lot more efficient than a Mountain Bike on those conditions.


The bicycle came from Sears & Roebuck circa 1979. I decided that even if I buy a new road bike, that I wanted to keep the Free Spirit around since it was in such good condition compared to a few much younger bikes I have seen. The parts are old (Shimano) parts, but most of the following procedures still apply to most bicycles.

The first problem was that the wheels needed to be "trued" very badly, the crank was loose, it had lots of grime around the chain hardware, the brakes needed to be tensioned, and it had some out of order accessories. The accessories it had were a luggage wrack in the back which had a broken support (which is laying on the ground behind the bike in the picture), and a mechanical speedometer which had a loose cable and just made chirping noises. It also had "soft" plastic handle grips on the end of the dropped handle bars which were petrified and provided no cushioning.


I started by disassembling the whole thing! I cleaned all the parts with CLOROX(tm) disinfecting wipes because they have a cleaning agent which does no harm and are great for absorbing grime. I put the luggage wrack aside because it just got in the way of mounting/dismounting (and was broken). As for the speedometer, modern bicycle computers (speedometer, odometer, tripometer, etc.) are now inexpensive, under $12 at your local "superstore", and allow you to program your wheel size (unlike the mechanical one), so I replaced the huge speedometer with the little computer.


I took the wheels to the local bike shop and had them trued for $5/wheel. They still have a little jitter, but it's nothing compared to the thumping and wobbling that they had before. They had both lateral (off rotation axis) wobble and radial (tending to not form a circle) wobble. I can ride over 20 mph now and not leave the ground.


While the wheels were being worked on, I was able to remove the plastic grips a lot easier than I expected (these things have tendency to become attached). Rubber grips can be a real pain, but I figured the plastic grips would have been fused to the handlebars. I just inserted a flat-head screw driver (on the bottom side to avoid any visible scratching) in between the grip and the handle bar. I didn't pry with the screwdriver, rather just inserted and removed it several times, spraying WD-40 down the length of the screwdriver each time. After about three times, I was able to break each grip free by trying to twist the grip around the handlebar. Once it came free, I took out the screwdriver and worked it off. I cleaned the lubricant off the bars. I bought some handlebar gel tape from Bartrager, and installed them according to these directions since there were none in the box. I guess I have long handlebars because I didn't have to cut the length of the tape, I just made a cut to taper the distal end of the tape so it was flush with the handlebar cap.





The bicycle has a disk brake in the back which needed to be manually tightened because it didn't lock the wheel. The brakes in the front were also too loose. Tip: If brake pads don't lock the wheel, they need more tension. Take the wheel off of the frame, and ask an assistant to hold the pads together. If your caliper makes it easy to disengage the recoiling springs, you won't need an assistant. Taking the wheel off will provide enough slack to make the adjustment--I found it was impossible otherwise. Adjust where the steel cable is fastened on the caliper side about a centimeter and tighten everything back up.


The bike was back in order but the crank still felt bad because it moved inside the frame. It's a one-piece crank and is a lot simpler than I thought before. Take the chain off first. It has a big locking nut which you'll need a big wrench for. Note that the threads are in the opposite direction from most threads, so you take the nut off by turning it in a clockwise direction. Under that, there were some washers which act as dust covers. There is a big nut that the ball bearings ride on which needs to be finger-tightened, it was loose and this is where the crank wobble came from. I de-greased the ball bearings and the journals inside the frame. It was essentially dry inside just a lot of black deposits on everything. There was some fatigue on the right-hand (gear) side where the ball bearings either crashed down or the bearing retainer was hitting. With one-piece cranks, look inside where the crank fits and look for the obstructions from the other tubes. Find a place to fit the corner of the crank and angle the crank through as to take the gear away from the frame. This will give you more space and will let the crank rest. After everything was clean (I had to use an abrasive brush in some places), I greased everything up as much as I could and put everything back together. I used a screwdriver to make the final torque on the hand-tightened nut, I stopped as soon as I felt no wobbling of the crank. When you put everything back together, you should be able to spin the crank and it should keep spinning for a while. If it doesn't make it more than a few turns after you let go, it's too tight.


After a few other adjustments, like the kickstand position, everything was ready to go. The bike feels a lot tighter like a new bike would. All the rattling, chirping, and wobbling is gone.

The bike will need new tires soon (the thin tires don't last very long), I have about 300 miles on mine and the tread in the back is disappearing. When I replace these, I'll try to disassemble the bearings on the wheels and try to revive them like I did the crank bearings. I'll also replace the chain at that time.


Tuesday, March 13, 2007

Computer Internal Dust Solutions


It seems like opening up my computer (or multiple in my case) and blowing it out every month is releasing too much dust back into the air, and all those particles that were stuck in there can wreak havoc upon your moving parts (fans). Assuming you operate electronic devices which have ventilation fans indoors, try the following.

Get a HEPA filter and run it, at least on its lowest setting, all the time.
The electricity it takes to run such filters is completely eclipsed by how much dust they remove from the indoor air and prevent those particles from being stirred up again. It's better for human breathing, and better for devices with moving parts. Also, if the filter circulates the air, your components might run cooler.

Install low-impedance dust filters in front of your computer's ventilation intakes.

Many computer cases are already shipping with single-layer plastic mesh filters which will stop most huge dust particles (the ones you can see anyway). I decided to give it a shot and installed some extra dust filters on the intakes of two computers. One computer had side ports which were completely open (no, fan, just big holes). NOTE: If you have filters installed, air will follow the path of least impedance, so either block or put filters over all air passageways that flow into the case. Don't put filters on exhaust ports (ports which blow out).
I decided to use WEB Vent Filters, but these have a few drawbacks: they have fibers which come loose, and are higher impedance than the coarse foam. Coarse foam like that in SHOP*VAC Foam Sleeves is preferred for low impedance of air flow, but doesn't offer good filtering of smaller particles. Both are readily available at the local hardware store.



I put WEB Vent Filters on the outside of the case (so they wouldn't get sucked into the fan) for one, and in between the case and the air duct for the other. On the other computer, I took the front panel off, and installed the filters over the intake fans, but under the outer cover. The only concern I have now is cleaning these. I'm hoping that after the one-to-two month interval, I can vacuum the filters externally to clear large debris back out through the intake, and then the next interval I can remove them and wash them under water.


WARNING: Remember, the foam should be low impedance! Any dust filter you install over a ventilation port or fan will impede the flow of air through your device. Fans will spin a little faster, but air flow will be slower. Make sure this doesn't cause any heat issues, and either remove the filter or install more fans if necessary. Inevitably, over time the filters will become clogged and become further impeding, and will require replacement or washing.

Vacuum and dust often.
I know, this is common sense, but I've seen people who just have a million Duster cans and they blow out their computer whenever it starts to make noise. Grinding noises are a very bad sign--this means that something is on or around the fan's journal (which usually has ball bearings), and the fan will most likely fail if not cleaned. Oiling the fan's journals using three-in-one motor oil can help, but the best bet is to keep the fans free from particles beforehand, and replace them when things start to go awry. Rule of thumb: if you have to clean it out more than once every one to two months, you have a dust problem. Also, blowing the dust around can cause a fan assembly to become dirty.

Finally, keeping these computer systems away from sources of dust is a good idea. Major sources of dust include laundry, bedding, and animals and humans.

Tuesday, December 12, 2006

Blowing out Fans

I took some highly compressed air and blew out a small processor fan (VIA EPIA) because it seemed to be making noise. It started to make more noise after I blew it out. So at first, I thought maybe I was using too much air pressure, but then I remembered that tiny fans usually make the most noise when compared to much larger fans. Later, I went and noticed that the fan was spinning a lot faster after I blew it out. Something I didn't expect to see. Then, I noticed a downward trend over the last half of a year since the fan was put into commission.

What I get from these pictures is that the fan is now spinning faster like it was half a year ago and the processor also started running cooler after I blew out the fan.





The conclusion: The failure mode of computer case fans is to develop (physical and electrical) resistance and spin slower and slower. They should be kept clean to prolong the life of the fan and the components they cool, but don't use too much pressure--you don't want to break the assembly.

If you're using compressed air -- you can use about 80-100 PSI, but don't use anything bigger than a Sports Ball Inflator or you'll have too much air velocity. Also, if you don't have a filter or anything on your compressor, you have to be careful about debris! Don't hold the air canister upside down or anything that might stir up dust or debris inside the tank. For most people, it's probably best to go to the store and get a can of "air" for your exact purpose.