Thursday, 21 August 2014

The stealth "near-fixie". An efficient bicycle for everyday use

Shimano Nexus hub gear. Really
very good, but not always what you
want. A wide range of gears comes
with a noticeable drop in efficiency.
Very soon after we came to the Netherlands I bought a fairly well used second hand town bike for getting about in the city. This bike had a seven speed Shimano Nexus hub gear. It's really a very nice gearing system, but I've never been entirely happy with the inherent inefficiency of multi-speed hubs.

After a couple of years it developed some problems and I "upgraded" to a three speed Sturmey Archer gear. Sturmey Archer three speeds are far more efficient than hub gears which have a greater number of gears. This is especially so in the middle gear which is a direct gear like a single speed bike. I set the gearing ratio so that I almost always used this middle gear. Sturmey Archer three speeds are extremely reliable, but this part was more than 30 years old and came with an unknown history. When it started eating its internals about a year ago I had to find something else quickly.

One of my daughters' bikes. Very
traditional shape. Single speed,
reliable, light and efficient.
Enter the single speed hub
My daughters both ride traditional Dutch single-speed sit up and beg bikes with back-pedal brakes. A couple of years ago, one of my daughters broke several spokes in the rear wheel when a friend jumped onto the back of her bike and I fitted a new wheel for her. It was her broken rear wheel that caught my eye when I was in a hurry to fix my bike - I quickly rebuilt the wheel and used it to replace the three speed. The shifter and brake lever stayed on the handlebars of my bike as this was to be a temporary measure.

KMC Z1 narrow chain. A 3/2nd
inch chain for single speed use.
A year later I found I was still riding single-speed with no particular desire to change. When it became obvious a couple of weeks ago that the chain and other parts of the transmission were far too tired to continue, I decided to make the shift to single-speed permanent. There were also several other parts which needed changing due to wear so I collected together all the parts and changed them this week.

A worn 36 tooth front chainring was replaced by a new 38 tooth chainring, a new 16 tooth sprocket was fitted on the back and a specially designed single speed 3/32nd chain from KMC linked these two together. The existing chaincase just needed a clean before it could protect the other new parts.

A new pair of my favourite flat pedals.
Not only was the plastic worn on the
old ones, I'd also worn well into the
metal ball bearing enclosures.
The pedals were also extremely worn. In many thousands of kilometres of riding, not only had the plastic parts won completely flat but I'd also worn right through the metalwork of one of the pedals to the extent that it was letting rainwater into the ball bearings. The old pedals still worked very well, but I replaced them anyway with an identical set of my favourite type of flat pedal.

At this point I also finally removed the extra brake lever and the gear lever which I've not been using for the last year and replaced my old bell with a type which is built into the handlebar grip. As a result, my handlebars are now very uncluttered.

The bike is now very simple and it's somewhat lighter than it was too. It rides really nicely with almost no noise at all.

A 38 tooth front chainring and 16 teeth at the back result in a gear ratio of around 64 inches. This is calculated as 38/16*27 inch approximate wheel diameter. It's equivalent to about 5.1 metres development (64 * pi / 39). This means that a cadence between 70 and 80 revolutions per minute results in a cruising speed between 20 and 25 km/h: a reasonable speed in town.

The old bike is rideable again. Just one gear now, but having adjusted the size of the rear sprocket and the chainring it's the right gear for me. That's important. This is an efficient and practical bicycle for everyday use, optimised for me. The saddle looks slightly sad, but it's still got some life in it.
Front brake
I recommend always having a front brake on any single speed bike even if your local laws allow doing otherwise. My front wheel is unchanged from when I bought the bike and includes a Shimano roller-brake. Sturmey Archer hub brakes are perhaps a better choice due to having no drag at all when not in use. Due to the workings being entirely enclosed, hub brakes like these have a huge advantage in reliability over both brakes which operate on the rim and also disk brakes. In six years and many thousands of kilometres of riding in all weathers, I've not even had to adjust the cable on this front brake.

AXA Defender lock. Secure. Permanent
fixture to almost any bike. Can be used
with additional chains and cables
Other convenience features
My bike also has a B&M front light running from a Nordlicht dynamo, a very comfortable saddleNorth-Road handlebars (IMO the most comfortable handlebars for upright bikes) and a bell built into the left handlebar grip. It's even fitted with coat guards, which again have no influence whatsoever on the performance of the bike, but reduce the chance of long coats being caught in the wheels.

The permanently mounted lock means I can leave it anywhere while the anonymous appearance makes it more likely that it'll be where I left it when I come back - a good thing for a bike which is often to be parked in the city.


Why call it "a near fixie" ?
Why do I refer to the bike I have now as a "near fixie" ? It divides the line between what people think of as a heavy utility bike and what is thought of as a light fixed wheel bike.

My old Holdsworth fixie. Built in 1948.
Really a nice bike to ride. Hope the
new owner is still enjoying it.
I used to have a fixed wheel bike, but I sold it eight years ago before we emigrated. My fixie had an 82 inch gear making it suitable for riding quickly through the countryside, but that wasn't suitable for collecting shopping in the town. It was nice, but for longer rides I had a faster and more comfortable bike so the fixie didn't get much use.

Shimano PDM-324 pedals are a good
choice for people new to SPDs or if one
one bike is used for several purposes
as they offer a choice of SPD or flat.
The attractive thing about fixies is the feeling of efficiency. Each turn of the pedals pushes you forwards. There's nothing "in the way". They're also very light. However, the downside with most fixies is that they have no luggage capacity, no mudguards, no chainguard, so they make a mess of your clothes, especially if it rains, the chain wears quickly due to being exposed to the elements, and they are not very practical bikes for everyday use. What's more, you must never let your feet fall off the pedals with a fixed wheel bike as this can lead to a loss of control and a crash. I always used clipless pedals and therefore had to wear dedicated shoes with my fixie.

Nothing is more puncture proof than
the Schwalbe Marathon Plus. The
wider sizes don't roll badly either.
On the other hand, the wonderful thing about Dutch everyday bicycles is that they're clean in use. Not only do you stay clean but the important parts of the bike stay clean too so they last longer. Dutch town bikes also have puncture proof tyres, a permanently mounted lock, dynamo lighting, and panniers or baskets to carry luggage (much better than having to carry an uncomfortable rucksack). These complete the picture of the perfect everyday use bicycle. What's more, you can of course wear anything when riding a Dutch style bike. I still use clipless pedals and special shoes on the bikes that I use for fast and long distance journeys, but they're not what I want for shorter journeys in town.

Think a chaincase is an odd
thing on a fixie? Mike Burrows
built a track bike with a carbon
fibre structural chaincase !
Great book too (you can get it
from Amazon. 2nd edition)
My "near fixie" is in effect a hybrid these two ideas.

Of course the bike isn't really a fixie at all because I've used a back-pedal brake rather than a true fixed wheel. However this gives the same efficiency as a real fixed wheel bike: the energy put into pushing the pedals goes directly to the rear wheel. The only difference is that coasting is possible and what happens when you want to slow down. Using a back-pedal brake brings the advantage that it's safe to use flat pedals and therefore I can wear any shoes that I want to. Because the chain is enclosed in a chaincase it does not get dirty and wear out so quickly as it would exposed. This helps efficiency because a dirty chain wastes a lot of energy. It also helps to keep me clean when riding.

Mudguards are also required to keep me clean and dry. Reliable tyres which may not look "fast" actually have quite low rolling resistance when pumped up hard. In any case they're infinitely faster than any other tyre with a puncture.

End result
The end result is a very efficient and practical bike. It has all the practicality of any Dutch town bike combined with the efficiency of any bike on which the transmission has been stripped down to the basics.

Of course I could have just asked the opinion of my daughters. They're amongst the millions of people who have been riding efficient bikes like this for many years. Or I could have looked back to my youth. I had a single speed back-pedal bike as a child and I went everywhere on it.

It's a myth that utility bikes are inherently inefficient and slow. They can be, but there is no reason for this to be case so long as the drive-chain is efficient, they are set up for the rider, they are well maintained, and the tyres are pumped up hard.

Monday, 7 October 2013

Installing dynamo lights on my own touring bike

Nordlicht dynamo60 lux Philips headlight, Philips rear light
and a V-brake boss bracket for mounting the dynamo.
In our webshop, DutchBikeBits.com, we sell a wide range of dynamo lighting because this is the type of lighting that we like to use on our own bikes.

In this blog post I install a Nordlicht Dynamo and a 60 lux Philips headlight as well as the battery version of the excellent Philips rear light on my own touring bike.

The Philips headlight is one of the very best dynamo headlights available. It has one of the best beam shapes, wide and very bright but with a cut-off at the top to avoid dazzling oncoming cyclists.

We recommend powering the Philips headlight with a Nordlicht dynamo - the best bottle dynamo ever made - in order to create a very effective dynamo lighting system which is easy to fit to an existing bicycle.

My old rear light on the left vs. the
Philips on the right. Probably the most
effective bicycle rear light anywhere !
At the time of writing, Philips were supplying free spoke reflectors with the headlight and rear light combination. Unfortunately those are no longer available. This offer was available only if you chose the battery powered version of the rear light. I now recommend the dynamo version of the light instead.

These front and rear lights are truly excellent. A notable upgrade from the lights I was using before, both front and back.

Installing on my own touring bike
I first mounted the dynamo using the
V-brake racket
In addition to the dynamo and light the only other part that I needed was a bracket to mount the dynamo. We sell three different dynamo brackets, one for front wheel mounting (off the fork), one for rear wheel mounting (off the seat stay) and one for mounting next to a V-brake boss. I chose for the latter.

The first part that I mounted was the dynamo. This required removing the bolt holding the left half of the V-brake on the front of my bike and reinserting the bolt with the bracket in place. It's an easy job, taking all of five minutes, but this of course has to be done with some care. If you are not confident about adjusting components around your brakes safely, please do not touch them but ask someone else to do the job for you. Please read the guide to setting up a bottle dynamo from a previous blog post.

After installing the dynamo I installed the front light. For most touring bikes this requires nothing more than removing the bolt which holds the front mudguard in place and using it to attach both the mudguard and the included bracket for the light. However on my recumbent bike there's no convenient place to attach the front light. This was resolved by reattaching the bracket after turning it backwards and using a single hose clamp to attach the bracket to the front boom.

The long wire from the front light reaches to the two connectors on the bottom of the dynamo. Cable ties should be used to keep the cable attached to the frame so that it cannot be damaged. If the light does not initially work, swap the two wires at the dynamo. It's possible for there to be a short circuit through the frame if they are connected the wrong way around. It's also important to have the switch on top of the light in the ON position.

The rear light is simply bolted onto the rear rack in the same way as the previous lock had been mounted. This light is bright even in daytime.

The Philips rear light is visible from a remarkably wide 320 degree angle so greatly increases the visibility of a cyclist from the side as well as from the rear. Also, because the light is spread over a large "race-track" shaped area, this gives a better impression of distance and is more pleasant to ride behind than are many single point LED rear lights.

My touring bike for 14 years, now with
better lights and reflectors than ever.
Finally I clipped some of the 36 spoke reflectors onto the spokes of my bike. I used just six on the front wheel and six on the rear wheel, leaving enough to provide a similar treatment on two more bicycles. A flash photo shows how effective these are when illuminated by car headlights, but note also the circular reflector on the tyres. Most of the tyres that we sell include this reflector.

A large rectangular area of the road is lit extremely well by the Philips headlight but the shaped reflectors used cut the beam off at the top so that it does not waste light and does not dazzle oncoming cyclists. These parts combine to make a very effective lighting setup both in order both to see and to be be seen.

We don't sell the Battery rear Philips light
Note that we don't sell the battery version of the Philips light. When the product was new, a small percentage of our customers for these lights found that theirs became full of rainwater and failed. Because this performance fell short of our quality standards we stopped selling the Philips battery rear lights. In fact, many models of battery lights are not 100% waterproof and can fail if they become saturated with water. We believe that if these lights are allowed to dry out should they become wet then not being entirely waterproof won't be an issue for most users, but we can't offer a guarantee. Rather than selling the lights we've therefore decided to give them as a gift to customers who also purchase a dynamo. By taking advantage of this offer you can put together a very high quality lighting setup for a very good price.

Note that this issue does not affect the rear dynamo light from Philips or their excellent front lights, both of which are weather resistant and guaranteed.

See also our full selection of bicycle lights

Friday, 31 May 2013

All shipments start their journey on our cargo bike



We've got happy customers in almost every country in the world, including so far afield as Australia and New Zealand, every state in the USA, Korea, Japan and China, as well as all across Europe.

However, every one of the deliveries starts off by bicycle. This sometimes means I find myself riding through the streets of Assen on a bike which is stacked up with a lot of parcels, as seen here.



Thursday, 6 December 2012

Snow. What tyres to make it safe ?

Judy a hundred metres from our home. The cycle-path is clear of ice and snow
We had four cm of snow last night, the first real snow of the winter. It looks wonderful, but snow can be dangerous for cyclists especially if it is not removed from the cycle-paths and if it becomes compacted.

Marathon Winter Studded Tyre
Assen is quite good at clearing snow, but there can still be small patches of ice hidden underneath, especially later in winter. That's why the first thing I did this morning, before breakfast, was change the front tyre of Judy's bike for a Marathon Winter studded tyre.

Fitting a studded tyre on the front wheel is the best insurance possible against a fall. Why only the front ? If the front wheel loses traction then a fall is almost inevitable and it is difficult to do anything to control such a fall. Falls due to the rear wheel slipping are much less common and much less scary.

Parent with children cycling this morning. This cycle-path
is clear, but you can't see it from this POV.
You can see from the photo at the top that many other people had already cycled this way. People tend not to make so many trips for pleasure, but cycling for utility purposes doesn't reduce much in the winter in the Netherlands.

I'll cycle with parcels containing customers' orders from our bike parts shop to the post office a bit later today and mine will not be the only bike there.

We still have studded tyres in stock. Order them now and they'll be with you in a few days.

Photos taken during the trip to the Post Office
The temperature didn't reach above zero all day today, so the snow mostly stayed where it was, unless it was swept. Some photos below show conditions for cycling in Assen
Safe conditions are also helpful for people with disabilities (written about several times before on the other blog)

Plenty of bikes parked outside the popular Hema department store in a pedestrian zone, and all ages of people arriving and leaving by bike.

Plenty of bikes at an indoor shopping centre.

Not many people use bakfietsen in Assen because conditions are safe for children to ride their own bikes. However, some people do transport smaller children by bakfiets.

A small "traffic jam" on the cycle-path. Utility cycling holds up in the winter because due to the lack of ice on the cycle-paths it is nearly as easy to cycle on a day like this as it is in the summer.

Tread on a bicycle tyre normally serves no purpose other than for marketing. Asphalt or concrete surfaces are harder than rubber, and grip comes from the small imperfections in those surfaces forcing themselves into the rubber. However, when there is snow the tread forces itself into the snow and that is where grip comes from. That is why any treaded tyre is better for snow. However, when it is icy tread doesn't work because ice is too hard to be deformed by rubber. At this point, the studs on the Marathon Winter tyres come into their own. They provide very small points of contact and pierce the ice. By doing so, you have far more grip than is possible with a rubber tyre. You can see both the tread marks in the snow and the black spots where the studs in my tyre pierced the ice underneath the snow, in the photo on the right.

For two wheeled bicycles, the most critical tyre is the front tyre. However, with a velomobile or other three wheel recumbent with two wheels at the front the situation is reversed. With that type of bike it is absolutely critical that the rear wheel does not lose traction as that can result in the bike rotating to travel sideways and turning over. That's why I fit just one Marathon Winter tyre to the rear wheel of my Mango making it possible to continue going for recreational rides in the winter in safety.

Saturday, 24 November 2012

Two excellent new lights

We've added two new front lights to our selection.

The Union UN-4268 has a very boring name, but it's a great light. 35 lux with a well shaped beam from a curved reflector at under €20 is pretty much unbeatable. But this light also has automatic switching dependent on light level (optional and intended for use with hub dynamos) and a powerful standlight which keeps it running for minutes after you've stopped.

The Basta Sprint headlight remains less expensive, but it's got a lower output than this one and doesn't have the other advanced features.

The second new light is completely different. The Philips Safe Ride Pedelec is a top of the range light which combines the 80 lux output of the same company's internally battery powered light with the smaller size of their excellent 60 lux dynamo light in a product designed specifically for use with pedelecs.

If you have a pedelec with less than impressive lights, there's no better upgrade on the market than this. The "motorcycle performance" comes from two high power LEDs and the best optics available which together reach 60 m without blinding oncoming cyclists or drivers.

Another thing that I like about this light is that the included mount can be used for other applications than pedelecs. In fact, it's perhaps the best possible light now available for mounting externally on velomobiles. Even the included bracket can be turned around to works for this application as you see in the attached photo.

Some DIY is needed to use the Philips Pedelec light. You have to supply both power and switching. However, this is made easy by the incredibly wide range of input voltages on which it operates - anything between 6 and 48 volts DC will do, meaning that almost all bicycle power supplies either for motor assist or for velomobile lighting, whether they're based on NiMH, Lithium or even old-school Lead Acid batteries are suitable without any extra circuitry being required.

Finally, this is of course nothing to stop you running this light on a normal bicycle used for commuting or touring. The 80 lux internal battery light from Philips provides much the same performance, but you can achieve longer running times from the pedelec light if you provide a larger battery.

You can find both lights directly by following the links above, or by browsing in our webshop.

Wednesday, 24 October 2012

Upright and comfortable - Choosing a saddle for everyday riding

Mountain bikes and racing bikes have narrow saddles. The reason for this is that they are ridden in a bent forward position. Your weight is spread between the handlebars and your legs as well as on the saddle and you need a degree of freedom for comfort and to avoid chafing.

However, if you ride a more upright bicycle your weight is supported much less by the handlebars and more by the saddle and your legs are in a different position relative to the rest of your body. This is also true if you convert a mountain bike to achieve a more comfortable and more upright position. While changing the stem and handlebars, don't overlook the importance of changing the saddle.

For a long time, we sold just one type of saddle at DutchBikeBits.com - the Selle Royal 8261, as shown on the left. This is a good everyday saddle for most people. It has a good shape, it's not overly wide, it has a little sprung suspension for extra comfort and we use it on almost all of our bicycles.

What's more, this saddle comes at a very reasonable cost, it lasts many years of everyday use and it has an advantage over some more expensive saddles that some people overlook - it's made of plastic.

What ? Plastic saddles are better ? If you want to ride your bike more than maintain then yes indeed they are. Plastic saddles do not need to be guarded against the weather as do leather saddles. If they get wet, you just brush off the wetness and they're dry again. Also, there is nothing to rub off and stain clothes, even when they are wet. That's why I find this to be the perfect saddle for riding everyday.

However, I'm not everyone. My wife, Judy, was never quite completely happy with the 8261. After some time spent deliberating, she decided upon a Selle Royal RoyalGel women's saddle as shown on the right. This is a softer saddle with a more sculpted form than the 8261 and it is specifically designed to suit women who want to ride upright. Judy now rides daily with this saddle, which apart from the different design has the same features as the 8261 which I and the rest of our family use.

We don't sell everything and we don't seek to sell everything. Rather, we sell those products which we believe in. It is only after Judy had ridden on her new saddle for several months that we took the decision to increase the range of saddles that we sell. The exact model of saddle that Judy chose was discontinued a year after this blog post was written. We now recommend the Manhatten saddle for a similar level of comfort, or the more unusual nose-less Rok design.
Sitting upright, comfortable, smiling
See also our anatomy of a reliable, everyday bicycle.

Thursday, 24 May 2012

Choosing the right size of tyres for your bike

47-406: A "20 inch" tyre.
47 mm wide, mounts on a 406 mm rim
Bicycle tyres come in a bewildering array of different sizes. It's absolutely vital to buy the correct size for your bike.

While tyres are mostly made of rubber, the most important dimension when fitting is that of the bead of the tyre, and this is reinforced either with steel wire (for most tyres) or with glass or other fibres (for folding tyres) so that the tyre won't stretch and come off the rim when fully inflated.

For this reason, bicycle tyres do not stretch and even sizes which are very close in size are not interchangeable.

Old fashioned ways of labeling tyres
In the past, wheel sizes were usually described as the outer diameter of the size of the wheel including a nominal inflated tyre. In countries which used imperial units these would be expressed as a size in inches (e.g. "26 inch" or "28 inch") while in metric countries the size was expressed in millimetres (e.g. 700 C or 650 A).

ETRTO 40-559 = 40 mm wide 559 mm
diameter rim. Also labeled 26x1.50 but
you are best off ignoring this old "size"
This system would work just fine if each size of wheel was described by a different number. However, that was not so. As an example, the "26 inch" wheel size used on traditional British bicycles is a lot larger than the "26 inch" wheel size used on traditional American bikes. British bikes were for many years imported to the USA, and when Mountain Bikes became popular, they brought the American wheel size to the UK. What's more, there are more "26 inch" wheel sizes than just these two.

There are also two different sizes of "28 inch" wheel, one of which is larger and the other smaller than the "27 inch" size. "29 inch" wheeled mountain bikes actually use the same diameter rim as the smaller "28 inch" size, so these two use smaller wheels than "27 inch".

The same problems arise with smaller wheels as well. The two most commonly used "16 inch" wheel sizes are both considerably smaller than 16 inches in diameter. The largest of the two measures just over 13.5 inches in diameter, while the smaller is nearly 2 inches smaller than this. There are also several different wheel sizes referred to "20 inch".

The metric versions of these measurements also cause confusion. A 700 C wheel is not the same size as a 700 B wheel but it is the same as one of the "28 inch" sizes, even though it's neither 700 mm nor 28 inch in diameter.

Inevitably, there is much confusion about wheel sizes.

The solution: ETRTO numbers
The most common size for Dutch town bikes and many touring
bikes. A 622 mm diameter rim with a 37 mm wide tyre
In 1964, the European Tyre and Rim Technical Organisation was formed. They're an organisation that few people have heard of, and I know little of what they've been doing for the last 50 years except that they've given cyclists a great gift in the form of a system for identifying tyre and wheel sizes which guarantees compatibility. This has been standardized internationally in the form of ISO 5775, but most people still refer to these figures as "ETRTO numbers".

The "ETRTO number" consists of two numbers separated by a dash. The first gives the width of the tyre, while the second gives the diameter of the rim which it fits. For instance, 37-622 indicates that a tyre has a width of 37 mm and is to be mounted on a rim of 622 mm diameter. This is the most common size for Dutch town bikes, and is also a common size for touring bikes everywhere.

Buying a replacement tyre
Before buying a replacement tyre, inner tube or wheel, first check the writing on the side of your existing tyre and find the ETRTO number. To help you find an exact match which will work on your bike, all the tyres and inner tube as well as the wheels in our web shop are listed with their available ETRTO sizes.

You do not always have to buy the same width of tyre as you had before. While it is not a good idea to fit a very wide tyre onto a very narrow rim, nor a very narrow tyre onto a very wide rim, in principle any tyre of any width will fit on any rim which is the correct size. In practice we suggest not going too far from what the manufacturer of your bicycle fitted. For example, if you currently have 32 mm wide tyres, then fitting a 37 mm wide tyre instead will likely give a bit more comfort. However, make sure you have enough clearance in the frame and under mudguards for a larger tyre size.

Recommended tyres and sizes for different types of bikes
Below we make some recommendations for some types of bikes. We supply a much wider range of tyres than this, so if you need a different size, please check all of what we have, and contact us if you need a size which isn't listed

You should always make reference to the ETRTO number on the side of your existing tyres before buying any tyre. Please take our recommendation, but confirm that these are the exact tyres you want by checking your tyre size yourself before ordering. If you are changing the width of the tyre that you use, make sure you have a new width that will work on your rims and in your frame:

Type of bikeTyre sizeOld sizeRecommendation with link to where to buy
British Three Speed37-59026"Marathon Plus, Marathon, Delta Cruiser
New Dutch town bike37-62228x1 3/8Marathon, Marathon Plus, Delta Cruiser
"Old" Dutch town bike40-63528x1 1/2Marathon, Marathon Plus, Delta Cruiser
Modern touring bike28-622 to 37-62228" / 700CMarathon Plus, Marathon, Marathon Supreme
Racing bike20-622 to 28-62228" / 700CDurano / Durano S, SportContact, Grand Prix
Old racing bike20-630 to 32-63027x1 1/4Marathon
Mountain bike47-559 to 55-55926"Furious Fred, Marathon Winter, Big Apple
Mountain bike used on road32-559 to 50-55926"Big Apple, SportContact, Kojak, Marathon, Marathon Plus
20" wheel folding bike28-406 to 47-40620"Kojak, Marathon, Marathon Plus
16" wheel folding bike28-305 to 47-30516"Marathon, Marathon Plus
Brompton / Moulton35-34916"Marathon, Marathon Plus
Kronan54-584 or 47-62226" / 28"Kronan tyres
(Kronan men's and women's frames are different)

Profile
It is not possible for a bicycle tyre to "aquaplane" because speeds are too low, and pressures are too high. Therefore, a profile is not needed on bicycle tyres to increase grip in the wet.

Top to bottom. Speed & good grip: Kojak
Everyday use and touring: Marathon
Ice and Snow: Marathon Winter
When on a hard surface (concrete, asphalt), grip comes from the tyre deforming over small sharp edges in the surface, not from the surface deforming to fit the tyre, for this reason, a complete slick tyre provides all the grip you need on such a surface. What's more, a tyre which has a tread pattern will generally have a higher rolling resistance due to deforming of the tyre as you ride along. For this reason, a completely slick tyre (like the Kojak) would serve most people well most of the time.

However, tread on a tyre is useful in some circumstances. If you sometimes ride on unfinished paths, mud, sand and snow, then a slight tread pattern is useful because the surface will then deform around the tread and provide extra grip. It is for this reason (as well as that new tread patterns look good in marketing materials) that most general purpose tyres have a slight tread.

A more extreme tread pattern is needed for more extreme circumstances. Those who do cross country riding or mountain biking on rough paths benefit from an aggressive tread, and of course this becomes more extreme in examples such as the Marathon Winter which go as far as having metal studs to pierce through ice.

Tyre Pressures
It is important to maintain correct tyre pressures. While it can be It is more common that people run their tyres at too low a pressure than too high. If the pressure is too low then too much of your energy goes into deforming the tyre as you cycle, and this makes cycling considerable less efficient.

If you can easily deform a tyre with your fingers then it is almost certainly under-inflated. All bicycle tyres run at higher pressures than car tyres, and car pumps are often not capable of achieving high enough pressures for a bicycle.

Racing bike tyre with "French" 700x23C
description alongside ETRTO
Narrower tyres need higher pressure than wider tyres. The racing bike tyre on the left has a recommended pressure between 6 and 10 bar (85 to 145 psi), while a wider mountain bike tyre may need just 2 to 3 bar (30 to 45 psi).

Narrow tyres may damaged quite quickly by too low a pressure, while some tyres (notably the Schwalbe Marathon) have been reformulated to make them more resistant to damage due to low pressure.

For everyday use, a thumb test (if you can deform the side-wall of the tyre with your thumb, pump it up) is enough for most people. However, we also stock the very good Schwalbe digital air pressure tester for people who want to make sure their tyres are at a suitable pressure. We also sell a range of pumps suitable for getting your tyres to a suitable pressure.

Note that with tyres with puncture resistant layers, like the Marathon Plus, if you try to test the pressure by squeezing the running surface of the tyre, all you'll "test" is how soft the anti-puncture layer is. It's important to do this on the sides of the tyre, squeezing between thumb and forefinger.