Wednesday 18 September 2013

Helmet Mirrors

The greatest hazard of cycling on rural roads is dangerous overtaking by motor vehicles. This can be passing too close or passing going into a blind bend or hilltop. The closest I came to being killed on a bicycle was on a straight stretch of road about two years. A jeep driver passed me much too close, but the real danger came from a trailer that was wider than jeep. I still clearly remember looking down and seeing the trailer mudguard a few inches from my foot.

Mirror on my Oakland
After this incident I decided to get a mirror. The first one I tried was a handlebar mounted mirror. But there were several problems with this. It was subject to a lot of vibration and didn’t give a really clear view. It was a long way from my middle aged eyes and even under the most favorable circumstances gave a poor view of the road behind. It constantly came loose and needed repeated tightening. It was always subject to the risk of being broken if the bike fell over. And as my fleet of bikes grew it was not convenient to move it between bikes.

After a few months I gave up on it and replaced it with a Zefal Z-Eye Mirror, which attached to my helmet. Since that day I have never rode without it. The mirror attaches to the helmet with a sticky pad and velcro. I had doubts that the pad and velcro attachment would last but after over two years it is still working well.

A helmet mounted mirror solves all the problems of a bike mounted mirror. While still subject to vibration it is a lot less. One helmet mirror will cover a fleet of bikes. Being much closer the the eye it gives a much better view of the road behind, important if like me your sight is not as good as it once was. It will not be damaged if a parked bike falls over.

The Blackburn Helmet Mirror
A helmet mirror has several clear advantages over one mounted on a bike. It allows you to take a quick glance at the road behind without loosing focus on the road ahead, you don’t have to look down as with a bike mounted mirror. But perhaps the greatest advantage it that with a little head movement it is possible to scan the whole road behind. This is very useful as it allows you to keep an eye on a car in the critical few meters as it finally comes up alongside.

I am agnostic on the great helmet debate, having never fallen off a bike since I was small child. I feel just as happy riding without a helmet, but since I got a helmet mirror, I always wear a helmet but as a platform to mount a mirror on.

I got my helmet mirror from Wiggle, it is still available from them for 14.46 euros but has to be ordered, which takes two or three weeks. I’ve just ordered a Blackburn helmet mirror from Rose Bikes in Germany, so as to have a spare, they have them in stock and they sell for 9,95 euros.

Zefal Z-Eye Mirror from Wiggle


Blackburn Helmet Mirror from Rose Bikes 


Monday 22 July 2013

Cycling and Power Consumption

I was thinking in recent days about the power consumption involved in cycling. I knew from experience that speed costs energy, but how much I didn't know. I went looking for an online cycling calculator and found http://bikecalculator.com/. I inputted my weight 154 pounds and my loaded touring bike (bike and cargo) at 55 pounds and started to play around with different speeds, on level ground. As I suspected power consumption increased rapidly with speed.

A brisk walking speed is about 4 mph, at this speed it takes about 10 watts to keep me and my touring bicycle moving. At six mph energy consumption jumps to 18 watts. Eight mph needs 35 watts. Ten mph will burn 43 watts and after this power consumption increases rapidly. Twelve mph will need 64 watts. At fourteen mph it takes 90 watts. Sixteen mph needs 124 watts and twenty mph requires 217 watts.

It takes five times more energy to move a bike at 20 mph than it does at 10 mph. The modest jump in speed from 10 mph to 14 mph doubles the energy used.

When I go cycle touring my aim is to maintain an average speed of around 10 mph, as I can keep going for many hours at this speed. The longest I've yet cycled is 146 miles in a day, to do this I spent nearly 15 hours out of 18 on the bike. At the end I was mildly tired rather than exhausted.

I also tested out the impact of weight on power consumption. My Carrera TDF road bike weighs 26 pounds, to move it at 10 mph takes 40 watts, a saving of only three watts over a 55 pound loaded touring bike. At 20 mph it takes 210 watts to move the road bike a saving of only 7 watts on the touring bike. On flat ground there is very little difference in the energy needed to move a loaded touring bike and a light road bike.

Even a very heavily loaded touring bike will not take much more energy than a light road bike. The heaviest weight I ever carried (bike and cargo) is 79 pounds, to move this at 10 mph only needs an extra 6 watts over a light road bike.

Weight does however tell when climbing hills. Climbing a 5 % gradient at 4 mph on touring bike will burn 109 watts. The same slope can be climbed at the same speed on a road bike for 84 watts.

The question of power consumption is a bit more complex than this, it fails to take account of things like rolling resistance of different tyres, and how well serviced a bike is. But it is a good rough guide to the kind of power consumption involved in cycling.

Monday 17 June 2013

The Raleigh Oakland Reviewed Part Six

It's two years this month since I bought my Raleigh Oakland. Since then I've done just over 15000 km on it and it still remains my bike of choice for everyday riding. I've kept it properly serviced and it rides even better today than it did the first day I rode it.

A lot of the components have been changed in the last two years, but the shifters, derailleurs, brake levers and brakes have lasted and still show no signs of wearing out. The frame, forks, headset, stem, handlebars, grips chainguard, saddle, seatpost and front mudguard have all lasted, are still in excellent shape and all look like they will give many more years of service.

The chainwheels, rear sprockets, rims, pedals, rear hub and rims have been replaced once but the replacements are still in good order and will all give plenty more service. The rear mudguard has also been replaced once. I've lost count of the number of chains and brake blocks I've gone through. The brake and gear cables have been replaced several times. The bike is on its second set of tyres.

You can still buy an Oakland online in Ireland from Eurocycles.com for € 309.99. or in the UK from Rutland Cycling for £174.99. Although a lot of the bigger retailers like Evans Cycles no longer sell it. It has also disappeared  from the Raleigh.co.uk website, so perhaps it is no longer in production. But there will be lots of them on the second hand market for years.

The next upgrade, Shimano hub gears
When I first reviewed the Oakland in September 2011 I had only done 3000 km and I wrote "You could spend a lot more on a hybrid bike but I doubt you will beat the Oakland on value for money". Almost two years later with 15000 km done I still stand over that statement. Back then it could be bought from Eurocycles for only € 230 but even at the current price of € 309.99 this bike remains great value.

The original wheels were machine built, so if you buy an Oakland get the wheels trued. The chainwheels are poor quality but will give long service if the gear changes are done gently and when they wear out replace them with good quality chainwheels. Regularly change the chain and the brakeblocks.

I'm planning a major upgrade to my Oakland, in the near future. I'm saving for a SHIMANO Nexus 8 speed gearbox hub with back pedal brakes. This currently costs € 154 from www.rosebikes.com in Germany. I will need to widen the rear dropouts by 5 mm to take this new hub, but with the Oaklands steel frame this will not be a problem, all that's needed is a six foot long piece of 3 x 2 timber and a stool. I will then change the front triple chainwheels for a single and enclose the chain in a chain case. When I complete this upgrade I will have turned my Oakland into a low maintenance utility bicycle, with the chain and gears enclosed and protected from rain and grit and no more brake wear on my rear rim.

Raleigh Oakland Reviewed Part One
Raleigh Oakland Reviewed Part Two
Raleigh Oakland Reviewed Part Three
Raleigh Oakland Reviewed Part Four
Raleigh Oakland Reviewed Part Five


Available Online from

Eurocycles
Rutland Cycling

SHIMANO Nexus gearbox hub Inter 8 SG-8C31

Monday 27 May 2013

The Raleigh Royal Reviewed Part Three

Last week I pulled the Raleigh Royal out of its winter storage and serviced it in preparation for the 2013 touring season. With almost 2000 miles done since I bought it last year, there was quite a bit of work required.

Mavic A119 700c Rim
 The biggest job was replacing the rims. I had not changed the brake pads since I got the bike and this was a serious mistake. The wear indicator grooves had vanished. The wheels were rebuilt with two A119 Mavic rims and the old hubs and spokes.

Clarks 60mm cantilever post type brake pads were used front and back. In future I will be paying much closer attention to brake pad wear. This is probably more of a factor on touring bikes, the kinetic energy of a fully loaded touring bike at high speed is much greater than a lighter bike and this is reflected in the rapid wear of the rims. Based on this experience I would probably buy a touring bike with disk brakes.

One of the pedals had developed a crack in the casing. I replaced the pedals with a set of Wellgo single cage M20 flat pedals. From the clearance section in Chain Reaction Cycles for the knock down price of €11.12. Very good value, but now sold out.

The Royal was fitted with an eight speed cassette, which had a 28 tooth low gear. I replaced this with a Shimano Acera HG41 8 Speed MTB cassette, with a 32 tooth low gear, just a little lower for getting up the steeper hills.

The chain was overdue a change. The new chain is a Shimano Altus HG40 6/7/8 speed.

The bike is now riding really well. Total cost of parts €86.63, but the bike is ready for the road. All I need now is some warm, dry weather. I have three tours planned for this summer, the west of Ireland awaits.

Raleigh Royal Reviewed Part One

Raleigh Royal Reviewed Part Two


All parts from Chain Reaction Cycles


Mavic A119 Road Rim 2013
€19.66 (RRP €22.14)

Shimano Acera HG41 8 Speed MTB Cassette 
€12.28 (RRP €20.90)

Clarks 60mm Cantilever Post Type Brake Pads
€3.12 (RRP €4.90)

Shimano Altus HG40 6/7/8 Speed Chain
€8.59 (RRP €12.28)

Thursday 25 April 2013

The Yuba Mundo Reviewed


After almost two months and 500 miles I still love my Yuba Mundo Cargo bike. I use it for my bike mechanic business, and can carry all my tools and spare parts. When fully loaded the total weight of the mobile bicycle workshop, including the container is about 30 kg. I have ridden up to 40 miles a day with this load, in very hilly country and I can ride up even the steepest hill.

My mobile bicycle repair workshop
The bike weights about 21 kg, so with 30 kg of cargo, this tips the scales at 51 kg. The bike handles very well with this load. It is stable at a speed of 4 mph hour climbing steep hills and equally stable at 34 mph coming down them.

I have a lot of experience with heavily loaded touring bikes, but the Yuba Mundo when loaded is much more stable and handles much better than a heavily loaded touring bike. The Yuba can carry a heavy load on the back without affecting the steering, once most of the weight is stowed forward of the rear axle. On a fully loaded touring bike some of the weight has to be carried on the front forks to balance the bike, this makes the steering and handling heavier. No such problem with the Yuba.

Two bicycles for delivery
Unloaded the Yuba is not fast, the heavy frame, 26 inch wheels and 1.75 tyres make it a poor choice for normal utility cycling, unless you need to carry cargo, a hybrid bike would be a better choice for commuting. But if you need to carry cargo the Yuba is an excellent choice.

I’m very happy with the gear ratios I chose, the biggest back sprocket has 28 teeth and the smallest front chainwheel has 22 teeth. This gives a very low, low gear which I need for hauling big loads up hills. If you live in flat country you will not need such a low gear.

I am delighted with this bike, I bought it instead of a van for my bike repair business. It is more than up to the job and I have no regrets on choosing a cargo bike instead of a van.

Yuba Mundo Cargo Bike Build Part One
Yuba Mundo Cargo Bike Build Part Two

Friday 29 March 2013

Rebuilding a Ten Year Old Bicycle


I’ve just finished rebuilding a ten year old bicycle for a friend. A steel framed "Goldrush Prairie" it was used for several years for a short daily commute, back in the days of the Celtic Tiger. It has been laid up in a shed for several years. A typical low cost bike of the period, it has a six speed freewheel (with a big gear of 28 teeth), three front chainwheels, 26 inch wheels and off road tyres. Like most six speeds of the period it has 126mm rear dropouts (modern dropouts are usually 130mm).

The Goldrush Prairie
The rear hub and the front rim were badly worn, and many of the spokes were rusted. The back wheel was rebuilt with a Shimano RSX A410 hub (an old style 126 mm hub), it came from the clearance section of Chain Reaction Cycles at the excellent price of 8.88 euro. The wheel was completed with a Sun Ditch Witch 26” rim, and 36 DT Swiss Champion PG black spokes (18 262mm and 18 264mm), also from Chain Reaction. The old front hub and back rim were combined with 36 264 mm spokes to build a new front wheel.

The wheels were shod with a pair of Michelin City MTB road tyres. These are a really ground utility tyre, with maximum inflation of 85 psi, they are a good rolling tyre when fully inflated.

The Rebuilt Back Wheel
The Shimano RSX A410 rear hub was fitted with a SRAM PG730 7 speed MTB cassette. The old six speed derailleur (a rear hanger model) was replaced by a Shimano 6/7 speed TX35 direct fit. A rear derailleur adapter was needed to mount the direct fit derailleur. This lowered it by 10mm and created sufficient clearance between the derailleur and the biggest 32 tooth back gear. The old six speed Microshift shifter is gone, replaced by a SRAM MRX 7 speed twist shifter.

The old style adjustable bottom bracket was replaced with a 68mm x 118mm semi sealed unit. New back brake callipers and new front brake pads were fitted. All cabling was replaced, as were all wheel bearings.

The cranks and chainwheels on the bike had been changed several years earlier and were fine. The headset was solid and working fine so it was not stripped.

The Shimano Rear Derailleur Adapter
It took 150 euros of parts to restore the bike. Most parts were bought online at discount rates, if they were bought in local stores like Halfords, they would have cost about 250 euros. Halfords will sell you a bike for that kind of money but it will have machine built wheels, old style bottom bracket and freewheel, cheaper tyres and poorer components. And it will ride poorly. The restored bike has a good steel frame, hand built wheels, quality tyres and a significant transmission upgrade. It rides really well. A new bike of similar spec would cost around 500 euros.

With regular care and maintenance  and a regular change of drive chain this ten year old Goldrush Prairie should be good for 10,000 km before it needs serious work again. Many old steel bikes have good frames with many potential kms of riding still in them, they are laid up in millions of sheds and garages all over the world. For about 150 euros and a days work they can be rebuilt into first class utility and commuter bicycles.
The Shimano RSX A410 rear hub











Monday 18 February 2013

Yuba Mundo Cargo Bike Build Part Two


Since posting the first installment of the Yuba Mundo build in December, its taken two months to complete the build. The Yuba Mundo is ready for the road.

Ready for the road
In December it was fitted with a 122 mm bottom bracket but this turned out to be incompatible with the Suntour Duro T324-P8 cranks and chainwheels. It was replaced with a 113 mm bracket, stripped from another bike. The Shimano FD-C050 front derailleur was also incompatible with the Suntour Duro, and was replaced with a Shimano FD-C051 derailleur.

The Yuba Mundo stand from Yubastore Europe in Germany cost almost 100 euros. It's a solid, wide stand and essential when the bike is heavily loaded.

The back wheel was fitted with Clarks CMD-8 mechanical disc brakes. After a little fiddling they were easily installed and adjusted and are working well.

Clarkes Disc Brake
The biggest problem of the build was the SKS Blumels MTB mudguards (fenders), from Chain Reaction Cycles. I could find no provision on the Mundo frame to attach the back mudguard stays. In the end the stays were removed and the rear mudguard held in place with wire. Not very elegant looking but quite effective.

On the front wheel the bracket for the front disc brake obstructed the mudguard stays. The stays had to be bent around the brake bracket. I bought disc brakes for the front but haven't figured out how to fit both disc brakes and mudguards at the same time.

The Yuba Stand
The other big fault is that the frames paint work is poor. It's about the worst finish I’ve ever come across on a frame. The paintwork strips very easily.

I spent extra money on tyres and the crankset, so the bike has a slightly higher spec than one bought fully built. The bike is now ready for the road and the total cost of the build is about 1300 euros, about the same as buying it fully built. It took many hours of labour but was a valuable learning experience.

Now for the road testing.

Yuba Mundo Cargo Bike Build Part One

Yuba Stand from the Yuba Eurostore
79,90 + shipping

Shimano FD-C051 Dual-Pull Top Swing Multi-Fit Front Derailleur from Halfords
€12.99

Clarks CMD-8 Mechanical Disc Brake from Chain Reaction Cycles
€22.90

SKS Blumels MTB Mudguards Set from Chain Reaction Cycles
€20.91