Wednesday, 20 November 2013

Page Speed Insight: Java Script

Page Speed Insight: Java Script - Introduction

If you adminester your own website then you may be annoyed as I am at the apprent change of heart google have had with reagrds to placement of java scrpit in your pages html.

I do not have much java script in my website just "plus one" and some feed convertors.

Page Speed Insight: Java Script - The Problem

Upon running page speed insights you will see the following:

"Your page has 12 blocking script resources and 2 blocking CSS resources. This causes a delay in rendering your page."
Now this is annoying becuase when I added the java script google gave the following guide for placemnet:

<!-- Place this tag in your head or just before your close body tag -->

So now it has decided the "head" is no good and I have to go through and move all the code down the the bottom of "body"? 

Al that is require is to move:

<script type="text/javascript" src=""></script>

to just above the close body tag.

So a simple fix but maually applied over 100 + pages this is a ball ache of the highest degree.

Tektro 984 Calliper Brake Review

Tektro 984 Calliper Brake Review - Intro

I while back I purchased a small folding bike with very poor brakes ( giant conway ), I am not overly fussy about stopping power but the front calliper brake on the bike is terrible.

Probelm is the bike has 1.75" tires and as such a calliper brake with very long reach is required. Idealy I wanted a dual pivot calliper as I belive these create a greater braking force, but depsite looking I could not find a dual pivot with the required amount of reach.

So after trawl of ebays finest offering I decided on the Tektro 984 which has a reach of 70 - 80mm.

Tektro 984 Calliper Brake Review - Build Quality

I purchased this brake as new but taken off a BMX, complete with lever.

Tektro 984 - Left Side

Tektro 984 - Right Side

Tektro 984 - Front

The finsih is good, and the bolts and nuts are of good quality. When attached to the bike the brake arms do flex under load, but with arms this long I supose that is unavoidable.

Tektro 984 Calliper Brake Review - Performance

The Tektro 984 provides more stopping power than my old calliper but I think this is mainly due to the change of lever. The lever supplied is a short pull lever for use with cantilevers or callipers, whilst the old lver was a long pull.

I suppose that the maths of the brake has not changed, still a single pivots, still the same length of drop, so really can I expect any improvement . .. not really.

Tektro 984 Calliper Brake Review - Specifications 

  • Long reach: 70-80mm
  • Post length: 51mm
  • Cable length: 700mm
  • Weight, caliper: 205g
  • Weight, lever: 83
Tektro 984 Calliper Brake Review - Alternatives

For a long reach application I think a single pivot calliper will always give limited stopping power. But unless you have braze ons for v brakes what are you to do?

Option 1 - A hub brake is always a good option, but this require a re-build of the wheel, most hub brake are 1000m wide which whilst OK for some BMX are unlikely to fit a folding bike.

Option 2 - Another option might be to replace the front forks, perhaps some off of a childrens bike that do have v brake mounts.

Option 3  - some sort of adaptor. You can get u-brake plates and some times v brake ones which might enable the fitting of a better brake type v or u to increase braking power.

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Wednesday, 6 November 2013

DIY Longtail Cargo Bike - Chapter 4

DIY Cargo Bike - Chapter 4 - Intro

Having built the frame and installing a minimum number of componenets for the maiden voyage there were a few niggly bits to sort out;

  1. Gears
  2. Lighting
  3. Test for Strength

Did you miss Chapter 1, Chapter 2, or Chapter 3?

DIY Cargo Bike - Chapter 4 - Gears

I only ever intened to have a 1 x 9 setup on this longtail cargo bike, as I don't like front mechs. So I ordered quiet a small chainset, a 34 tooth M-ighty chainset from SJS cycles.

34 teeth and a tight chain, just about OK

This would have been fine if the chain tension was very high, as with a single speed or hub gear bike. But the "flop" of the chain using my deriallier gear system caused immediate problems with the chain rubbing on the foot plates of the bike in all but the lowest gear (larger rear spocket gives more clerance).

So I tried to add in a chain "support which was a jockey wheel from a rear mech, and some peices of metal welded to the frame, to lift the chain up over the rear foot deck, this was a very noisy soluitoins with tons of rub in all but 5th (central) gear.

So in the end the soluiton was to get a larger chain wheel up front, not idela on a bike designed to ccarry heavey stuff, but I do value peace a quiet.

On ebay I found a single speed chainset with a 44 tooth chain wheel, so I bought that.

This works OK. I also had to trim back the inside edge of the foot rest to allow a little more clerance for the chain.

DIY Longtail Cargo Bike - Chapter 4 - Lighting

I am a fan of hub dynamos and the front wheel I had spare has a  got one, a Shimano DH-3N20 which is a good bit of kit, for lights I pinched the Busch and Muller Lumotec Lyt Senso Plus from my main bike, and purchased a Axa / Basta Ray Steady LED nothing to say other than a thank youto busch and muller for the extra long cables thery oprovide with there lights which reached from the front wheel all the way to the back.

DIY Longtail Cargo Bike - Chapter 4 - Test for Strength

There is quite a bit of flex in the bike, from side to side that is. But the loads will be applied downwards so I wasn't too worried abot that. I way 80 - 85 kg so I knew the bike was good for that.

Next load up was me plus a 20 kg parcel, which was strapped on to the foot plate at the rear , so that was 100kg.

Next load up was me and my two daughters (leap of faith I know) so that would be 110 - 115 kg. As you can see they are both very happy, as am I.

So happy days. All done. Expect some stupid pictures of me taking fridges to the dump in a few weeks. . . .

Update: 10/02/2014

After a few months of riding I have a small update. All there is to say is that the bike is doing well. We have had various family excursions on the bike, and I have taken numerous large parcels to the post office using it. The only modification since this post has been to reduce the size of the chain ring from 44 (yes I know) to 38 teeth. A lot easier on the knees.

Some pictures below of a large load.

Went about 3 miles with this load. An antique(ish) foot locker type thing.

Flood Risk

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Monday, 4 November 2013

Replacing a Light Switch with a PIR / Occupancy Sensor

Replacing a Light Switch with a PIR / Occupancy Sensor


Replacing a Light Switch with a PIR / Occupancy Sensor - Intro

A few months after moving house, and I have finally got round to replacing the very noisy (click, clonk) pull cord light switches in the bathrooms that wake everybody up. I opted for PIR motion sensors with adjustable "on" time, and sensors that keep the light off during daylight hours.

I purchased them from Total Warehouse an ebay shop.

Replacing a Light Switch with a PIR / Occupancy Sensor - No Neutral

I have replaced loads of light switches before, but guess what a PIR / Occupancy Sensor is not a light switch!

Nearly all generic PIR / Occupancy Sensors require a neutral wire to operate, and nearly all light switches do not have a neutral wire. the typical light switch works by breaking the positive side of the lighting circuit, so effectivly at the switch you have 2 positive wires (and an earth wire).

Replacing a Light Switch with a PIR / Occupancy Sensor - DO NOT DO THIS

These PIRs do not have an earth connection, ie they are un-earthed.  So this means the earth wire at the light switch is spare, and potentially could be used for a neutral wire. Of course there are numerous dangers with doing this, the earth wire is not insulated separately as it is not meant to be in constant use. It is also dangerous because it is not blue in colour and so future users my identify it wrongly. DO NOT DO THIS

So in theory (although I would not do this) you could swap the switch earth over to the neutral side of ceiling light rose, and then without crawling around in the loft you will have a neutral at the switch. You can check that you have the right wire by checking resistance from the switch to the rose along the chosen earth wire, it should be zero. DO NOT DO THIS

Replacing a Light Switch with a PIR / Occupancy Sensor - Solution

Hire an electrician and he . she will probably replace the switch wire with a 3 core + earth alternative, which will allow a properly insulated neutral wire to be sited at the switch.

Also there are PIR / Occupancy Sensors that do not reuqire a neutral, but these are around 10 times the price.

Replacing a Light Switch with a PIR / Occupancy Sensor - In Use

So is having a PIR / Occupancy Sensor useful. Errrr . . . .yes I guess it is, although you will need to carry a s small screwdriver around with you for a few days. The sensor switches on when you come in the room which is good, but how long it stays on for after that initial detection is set by twiddling the adjustment dials on the side of the unit.

Of course if you keep moving around then the light will stay on but if you are sitting down reading book then after a while the light will go off, a PIR would work well in say a kitchen where people are moving round allot, but in lounge I should imagine they would not be very useful. They are OK in the bathroom, on about a 2 minute delay.

Another problem with replacing light switch with a PIR is that light switches are tucked away in corners, where they can not "see" the whole room, 2 out of the 3 installed PIRs in our house had to be sited in central locations resulting in holes in the ceiling.

Illustrator Devon