Tuesday, October 30, 2012

Brake Reach Pitfalls

           We have a vintage Raleigh "Competition" road bike in the workshop for a complete makeover at the moment. It is an interesting project and will probably feature again in this blog before the transformation is complete. One thing that has cropped up already and is very common when doing these kinds of makeovers is 'brake reach'. It is not however just a problem with older style bikes it can cause issues on modern frames too, especially on those catch all frames that are designed to be built up in a variety of styles and need to accommodate a wider range of tire widths than a standard 23 or 25.
            Brake reach is basically the distance between the caliper mounting hole on the bridge,  to the center of the brake wear track on the rim.

            On a modern standard road bike this distance is going to be around 39-49mm and a standard short reach caliper from the big 3 will work just fine. Lots of manufacturers nowadays though are producing frames that can be equiped in various formats, a bike for all seasons if you will. This is where the brake reach figure can differ from standard and purchasing a short reach caliper is probably not going to work. The pads will hit somewhere on the tire instaed of the rim. Another problem scenario is with the older style frames as we have mentioned, the mounting bridge on these guys are usually set for the older style center pull styles that had a reach of around 61mm. Therefore a standard 39-49 short reach is never going to work.  Even what we commonly refer to as medium reach will have trouble as their range usually runs from 47mm - 57mm. The last tool in the box for a modern caliper is a long reach 55mm - 73mm.
             All this goes to show that you can never take anything for granted when changing parts on your bike. Measure, measure and measure again.

Sunday, October 28, 2012

Check the Pads

Tis the season to pay special attention to your brake pads, wet conditions are notorious for embedding grit and debris into your brake pads, I am sure you have all heard that long shoooshing noise the first time you apply your brakes after riding through a wet section or a puddle, that is the sound of grit being sandwiched between your pad and rim. What happens next is a lot of that debris gets pushed into the rubber of your pads and from then on gets applied to your rim every time you brake. Now, what also begins to happen is that little pieces of your rim get chiseled off and they end up in your pads as well. It becomes a vicious circle.
                You should keep an eye on the condition of your brake pads throughout the year but especially after wet or very dusty rides. Keeping the pads free from debris makes a big difference to your rims wellbeing.
                If you do see some grit and rim material in the pads the easiest way to remove it is by buffing the surface of the pads until you reach new rubber, free from the junk. Use 80 grit emery-cloth on a small block, if you just use the cloth on your finger you will place a concave profile on the pad. Do not use sand paper for wood, that stuff will put more grit in than it takes out.
               Also periodically check the rims for digs or rough spots caused by contaminated pads. Any rim trouble spots can be addressed by carefully using a 120 grit cloth. If in doubt come see your friendly bike mechanic.
Before; A road pad (top) and a mountain pad (below), both with rim material embedded
After; Same road pad after some buffing. Good as new.

Wednesday, October 24, 2012

Heated Bike Lanes on the Way

             An idea being looked at in Holland is gaining ground across other EU countries that suffer from icy winters, heating the bike lanes. The small town of 'Zutphen' in the eastern part of the Netherlands will likely be the first town to be equipped with the lanes, at the moment they are waiting for a final decision.
             The technology proposed for the paths is a modified Geo-thermal energy source producing enough heat to fend off the snow and ice on the paths.
             The Netherlands has an estimated 18 million bikes for a population of 17 million people, so seems like a good choice for the initial scheme. They have around 35,000km of designated cycle paths across their nation. The cost of the heated trail has been estimated at around $40,000 - $83,000 per mile of trail.
             If the technology is successful more of Europe's bigger cities will jump on board and already there are rumors that London is looking at a version for the city center.

Tuesday, October 23, 2012

Human Powered Helicopter Challenge

         Some very smart kids at the University of Maryland are closing in on a record and a $250,000 prize put up by the Sikorsky helicopter company. The challenge, which has gone unclaimed for over 3 decades, is to build a human powered helicopter, capable of reaching a height of 3 meters for a span of 1 minute. The machine must also be controlled to stay in a 10 meter box.
        Check out the video below, they are not quite there yet but I don't think it will be long before the good folk at Sikorsky are cutting a check.

Saturday, October 20, 2012

To Powder or Not to Powder...


A recent post on inner tubes "Latex v Butyl" has created interest in another of those topics which can stir passionate debate, whether to use talcum powder on inner tubes. So I shall offer my views on the subject and you can make your own decision.
           I shall state from the outset that I do not usually use powder when installing tubes. That being said I have customers that do and I have a canister of 'Johnson's' in the cupboard so, if requested, I can powder up a tube to keep everyone happy.
           Firstly, what are the reasons behind some people’s choice of using powder? Well, powder can make the tube easier to glide around against the tire when you are trying to wedge everything together. I know many people have trouble when trying to poke a tube into the tire and pinching the tube under the bead of the tire is a common problem for some. Also, when removing a tube from a tire, it is easier when dealing with a tube that was powdered. I have also heard the argument that when a tube is powdered there is less friction between tube and tire and less likelihood of failure from abrasion. Finally people see that there is often some trace amounts of powder when you get a new tube out of the box so therefore powder must be good.
            Okay, I think that covers most of the arguments that commonly get mentioned for the use of powder, now for my rebuttal.
            Starting from the bottom of the list, the reason manufacturers use powder is actually during the manufacturing process itself, it is not as some suggest them pre-powdering the tube for you. When the tubes are made the rubber becomes very hot, even by the time the process is over there is still considerable heat left. The powder is actually used on the inside of the tube so that when the tube is folded flat and pressed into the packaging the two sides of the tube will not bond together. Next time you have an old tube at hand cut through it and you will see a fine white powder coating the inside.
            Friction. I have never quite got my mind around this one. If anything you are creating a scenario to create more friction by using powder. When a tube is correctly inflated inside of a tire there really is no room for any movement between touching surfaces. Also we have all seen how a tube bonds slightly to the tire, if there was a need for any movement it would be very slight and the tube would be much better flexing instead of sliding against the surface as the powder argument suggests. And before the cries of tubes completely bonded to tires rises to crescendo, this never happens to the extent of tossing a tire away because of a tube that cannot be removed. I have replaced more tubes in my life than I have eaten hot dinners and never have I had a tube that refused to “Part Company” with anything more than a sharp tug. In fact that slight bonding helps out in another way too. When a puncture does occur, due to an errant thorn or some such, having the tube attached to the tire means that the air only comes out through the hole at that spot around the thorn, if you powder the tube and there is no bonding the air will escape from the tube into the cavity and be gone much quicker.
             Lastly, the installation. Here at least I do see a benefit for those who struggle with tube replacements. However, if you follow a set of rules such as, inflating the tube enough to give it body, make sure to get it seated up into the tire before popping the final bead on and never sticking tire irons in there, you should be fine. Most issues come when popping the last 6 inches of bead on and no amount of talc is going to help you there.

Friday, October 19, 2012

Sturmey Archer 3 Speed Hubs

Have been working on a renovation project this week, a Raleigh 20 folding bike. The bike was complete and looked to be in pretty good condition, apart from renewing the usual tires, tubes and cables, everything else has cleaned up nicely and gone back together without replacement of any internal parts. Back in the day they built things to last.

The Beast Laid Bare
                 As is often the case with bikes like this, I am the first person to see the inside of them since they were put together, this bike was no different and when it came time to open up the 3 speed Sturmey hub I was not sure what to expect. The hub was still working, albeit a little clunky in the changes, nevertheless I took that as a good sign. As is usual with the big hubs all the grease that had been originally packed in there had long since turned to a wood like consistency but, once all that had been chipped out of there, the parts showed very little sign of wear. These hubs never fail to disappoint, I have lost count of how many of them that I have rebuilt over the years but I have never had to scrap one.
The Gear System. 2nd gear is direct drive, 1st gear is a decrease of 25% and 3rd gear is an increase of 33% over direct. Clever stuff.

Monday, October 15, 2012

Butyl versus Latex. The Great Debate

Every year, as sure as leaves turn and fall, the perennial debate of "what are better butyl or latex tubes?" rears its head in the store. This year is no exception, brought to life by a group of riders traveling across the country and looking for a mediator.  Now I have learnt long ago when to keep my head down and look busy and this was one of those times. The rest of their trip gives me a headache just thinking of it. Anyway I thought that I might offer my thoughts on the subject here, where it is quiet…
                Firstly a little history, back in the day, the only game in town was latex rubber, basically latex is the stuff you pull out of trees and plants that can be formed into a rubber. Most plants exude some form of latex when they are cut or injured in some way. One tree in particular ‘Hevea brasiliensis’ was found to have great potential for commercially made latex rubber. Now I am no chemist so I will cut the lesson short on manufacturing natural latex, suffice to say it is produced from trees.  I should say that natural latex is, as it can be synthetically manufactured as well but originally everything from gloves to tires to condoms were made of natural plant based latex. Now everything was progressing fine until the advent of WWII. Amid worries about supply of rubber for everything from tire tubes to condoms a push was made for a substitute. Along came butyl, proper name Isobutylene Isoprene Rubber. The basis for this compound was developed by the German company BASF in the early thirties but was developed into what we know as butyl today by a couple of guys at Standard oil just before the onset of the war. Anyway I think that covers the how and the why but what is the difference and benefits of the 2 when it comes to your bike.
                I will agree that there are benefits to a latex inner tube and paired with a suitable tire they can be felt by most competent riders. The benefit comes in the form of better rolling resistance due to better or faster elasticity. When rolling, the tube is compressed and then, as it rolls along it springs back to its original profile. At the contact point the tire has a portion of its profile squashed to the road, obviously tire pressure and profile all factor in but as it is rolling the section that is leaving contact has to bounce back, the quicker this happens the less contact patch there is and by default the less drag. Latex is like a huge tight spring and it snaps back quickly. Butyl on the other hand acts like a hydraulic shock and bounces back slowly and in a controlled way, the energy is absorbed along with the heat.
                Other benefits include better feel when generally riding, for the reasons mentioned above, the tube also benefits cornering and basic feel.

A few things to consider when running Latex tubes.

·         Compared to butyl air leeches out quicker from a latex tube. Get used to pumping them up before the event to ensure proper psi.
·         Because of the high permeation rate, as mentioned above, do not use CO2 to inflate them. CO2 permeates through latex much quicker than regular air which is predominantly nitrogen.
·         They are lighter than a regular butyl tube, although some of the ultra-lite butyl are comparable. I have never been a big fan of the ultra-lite butyl tubes, they are extremely flimsy and the failure rate on them is very high which in my opinion negates any gain, especially on race day. Latex tubes in comparison, despite their delicate nature are surprisingly durable. They will shrug off lots of abuse. They will find any weaknesses in your rim tape though so be careful to install good tape well.
A standard Latex tube.

A latex tube will be beneficial to any good road race tire to a certain degree. That gain can vary from about 1.2 watts to about 2.8watts. Using a supple, high thread count tire makes a big difference. On tires utilizing some form of protective aramid belt or a thicker rubber tread the benefit will be considerably less.
Over the years latex has been definitely pushed under a rock when it comes to bicycle inner tubes and, honestly, that is probably the best for most riders. Butyl is much more suitable to the needs of most cyclists. It is thick and offers a little more protection and durability than latex. Butyl holds air better, it still needs topping off regularly but compared to latex it is significantly less permeable.
 Latex still has a place though, for those riders looking for ultimate performance from body and machine latex tubes can be a benefit. At this level any performance gain is always minimal but it is there. Running a quality latex tube in a quality race tire on race day is another of those gains.

Thursday, October 11, 2012

Tour of Britain 2013

The 2013 Tour of Britain dates have just been released and mark the 10th anniversary of the event. The route will be finalized and made public next spring but the dates are as follows; Sunday September 15th to Sunday 22nd September. The tour this year will also team with the ride London event that will take place in August.

Wednesday, October 10, 2012

Aston Martin Bikes

News this morning from the good folks at Aston Martin, builders of some of the best looking cars on the planet and of course James Bond would be walking everywhere if not for them. Well it seems that they felt the need to design a bike worthy of their name and came up with the "One-77" limited to a run of 77 and with a price tag of 25,000 pounds, roughly $40,000. Their website is a little sketchy on details but heck they look cool.

Thursday, October 4, 2012

New Lights

Another light, well it is the season, the Cateye "Nano". Lots of lights to choose from these days, the usual standard aa and aaa battery units, these are fine but the cost adds up quickly replacing batteries every five minutes. Rechargeable ones, with the battery pack that hangs in the bottle cage or a little bag under the top tube are o.k but a little inconvenient. Until this year the usb rechargeable units were not that great, now however we have a 600 lumen light without the added weight or hassle of a connected battery pack that can be quickly charged via a standard usb port on the computer. The nice features are the standard flash mode but also a setting that flashes one led while having the other shine a constant beam, see and be seen.

Helmet Mountable
Run Time High: 1.5 hrs
Run Time Low: 4 hrs
Hyper-Constant: 2 hrs
Flashing: 35 hrs