CCATP #604 – Bart Busschots on Tech of Buying a Mountain/City Bike

Bart Busschots joins us to talk about the technology decisions that go into buying a bike these days. I thought I knew about bikes, but I learned a lot about what’s changed just in the last five years. At the very end of the post, we have a video where Bart walks around his bike and points out each of the things he talked about in the recording and text below.

mp3 download

The Problem to be Solved

You’d like to start cycling more. Maybe you’d like some more exercise, maybe you’d like to avoid the traffic, maybe you’d like to do a little more to help the planet or some or all of the above. You want a general-purpose bike that will let you navigate suburbia, enjoy the open road, make the most of small winding back roads, and even brave the odd gentle trail, and preferably all without breaking the bank!

In short, you’re thinking of buying a mountain bike or a city bike and you’re finding the range of choices intimidating, and you’d like some help figuring out what you want.

My Experiences

I’ve been a keen cyclist for as long as I can remember, and since the very first time I got any significant amount of money (my first Holy Communion at age 6), I’ve been choosing and buying my own bikes!

I’ve always opted for mountain bikes, or their slim-down descendants, city bikes. I’ve always opted for the general-purpose bike, and never for anything specialised, either for extreme off-roading or for racing.

At the moment I do about 50km daily, partially commuting to work, and partially for mental recharge time and exercise. I have two bikes, a very old city bike for commuting, and a nice (relatively) modern mountain bike for my exercise/pleasure spins (a 2017 Big.Seven 500 from German manufacturer Merida).

Basically, I know a lot about general-purpose mountain/city bikes, and very little about anything else! So, if you know you don’t want that kind of bike, I’m the wrong person to listen to 🙂

The Aim of this Segment

It struck me recently that while the basic shape of the bike has hardly changed in a century — a diamond-shaped frame with three horizontal axels (front, rear & centre) and a vertical axel for steering — just about everything else has changed dramatically! There are just so many more decisions you have to make before you hit that big ‘buy’ button these days!

Unless you plan on spending an exorbitant amount of money, or, unless you get very lucky, you’re unlikely to find a bike that has exactly what you want without any tradeoffs. Instead, you’re much more likely to find yourself looking at the spec sheets for a short-list of candidate bikes trying to decide between them. In this kind of scenario you don’t just need to know what you want, but also, how much you want each thing. You can’t make tradeoffs if you don’t know whether having 27 gears is more valuable to you than having hydraulic disk brakes!

So, my hope is that this conversation will help you figure out what your next bike must have, should have, and what would just be nice to have.

Question 1 — Big-picture: Frame Shape?

Given our criteria, I’d argue you’re choosing between three broad options:

1. A traditional simple mountain bike — big frame with traditional angles
   • plenty of mounting points for accessories like drinks cages, mudguards, carriers, panniers, etc..
   • pretty much any accessory is likely to fit because there is plenty of room within the frame, and all the angles are normal
   • Not suitable for trails because of the lack of clearance when you stand over the crossbar
2. A city bike — like a traditional mountain bike, but with a slimmer frame.
   • Everything above, but lighter
   • Even less suitable for use on trails because the slender frame can’t accommodate wide tyres
3. An opinionated mountain bike — a small frame with more extreme angles (like my little 15″ Merida)
   • Assuming you buy the right size, should give you plenty of clearance over the crossbar so you can enjoy even quite challenging trails
   • Can usually accommodate very wide tyres, again, making it a better fit for trails
   • Will have fewer mounting points for accessories
   • Many accessories will not fit because of the limited room within the frame, or, because of the odd angles the various bars meet at.

Bearing in mind that I have zero first-hand experience, I would advise against a ladies frame with a low cross-bar. From an engineering point of view, this is an utterly compromised design with forces not being properly distributed around the frame. This design is the result of victorian morals which insisted that women must be able to wear dresses while cycling. Unless you plan to cycle in a dress, my advice is to steer clear of these structurally inferior frames!

Question 2 — Suspension

These days this is an easy question.

For a general-purpose bike, you don’t want, let alone need, rear suspension. Suspension is designed to dampen shocks, so by design, the suspension absorbs energy (technically it converts mechanical energy to heat). Rear suspension sits between your pedals and your driving wheel. With each rotation of the pedals, you’ll bounce the rear suspension, wasting some of that force you’re working so hard to generate!

You do want front suspension because it will protect your wrists and allow you to retain good control of your bike on rough terrain. Without front suspension, there’s only the tyre between your handlebars and the bangs and vibrations from the surface you’re cycling on. If that surface is in any way rough you won’t be able to hold onto the handlebars tightly, and that’s simply dangerous! Not to mention the risk of damaging your writs by making them absorb all those shocks and vibrations!

IMO, you need a so-called hard tail design, i.e. front suspension but no rear suspension.

Adjustable suspension is a nice-to-have IMO, but absolutely not vital (neither of my current bikes have it, though past bikes have and I’ve simply set it once and never changed it again!).

What is more important is the ability to lock the forks. This can be useful if you’re going on a long trip on a smooth road and is vital if you’re going to be carrying weight on your handlebars (we all know we shouldn’t do it, but we all do!).

Question 3 — Wheel Size?

Even just a decade ago this question would have seemed pointless since you would have had exactly one choice (within our area of interest anyway) – 26″ wheels or bust!

Within the last decade, the larger 29″ wheel started to make an appearance on regular mountain bikes.

What are the advantages of a larger wheel?

• Larger wheels can roll over obstacles more easily because they have a shallower angle of attack giving a smoother ride
• Larger wheels give better grip because they have a bigger contact patch
• Larger wheels carry speed better because they have more inertia
• Bikes with larger wheels need to have a longer distance between the front and read axles, giving a longer wheelbase and hence, a more stable ride

Great, so bigger is definitely better? Nope! There are disadvantages to larger wheels too:

• larger wheels mean larger frames, which means heavier bikes
• larger frames are less rigid, so handling is reduced
• unless you’re tall, larger wheels may simply result in bikes that are just too big for you!

A few years after the 29″ers made their debut a compromise option was introduced, the 27.5″ wheel.

My commuting bike is very old, so it has 26″ wheels. My modern mountain bike has 27.5″ wheels. In my experience, that’s the perfect wheel size, at least for me. I get all the advantages of a bigger wheel, but without the disadvantages becoming an issue. I’ve never owned a bike with 29″ wheels, but I have tried them out, and they’re just too big for my 5″8′ body!

Question 4 — Tyres

Tyres are vitally important! They are your only contact with the earth (unless you’re having a very bad day!), and the wrong tyre can literally kill you!

The conditions you expect to cycle in will determine the tyre that’s best for you.

On one extreme you have tyres designed for off-road use, they’ll be:

• wide — widths up to 2.125″ are quite normal
• flat in profile so the entirety of the wide footprint is in contact with the ground
• knobbly — lost of big chunky rubbery bits sticking out in all sorts of odd shapes at all sorts of angles to really bite into the ground!
• soft — they tend to be made from softer, grippier materials

Off-road tyres have some great advantages:

• they don’t sink into soft surfaces easily
• they can find grip on soft surfaces like gravel, mud, and even sand
• they can find grip on wet surfaces because aquaplaning is almost impossible with all those gaps between the knobbly bits

But, they come with some serious disadvantages:

• Lots and lots of drag! Lots of soft grippy rubber in contact with the road.
• With those knobbly bits they tend to be very noisy on the road.
• They will only fit on bikes with wide forks. The widest off-road tyres will only fit on the more opinionated mountain bike frames
• Because of the soft materials used, off-road tyres are also very quick-wearing, especially when used on hard surfaces like gravel and paved roads

In contrast, road tyres tend to be:

• narrow
• round in profile, so only a tiny part of the narrow profile is in contact with the road
• smooth — very few grips, just some slits to allow water to escape and hopefully avoid aquaplaning in most situations
• hard — the materials chosen tend not to be as soft and grippy

These tyres have obvious advantages:

• they have much much much less drag
• they are much quieter
• they are much harder wearing

But, they also have their disadvantages:

• they will sink into soft surfaces
• they have almost no grip on rough terrain

Like with the frame sizes, you don’t have to settle for either extreme, there’s a whole range of hybrid designs in between!

I like to ride with very wide tyres with a round profile and a hybrid grip pattern. Hybrid grip patterns have a strip of road-tyre-style slick grips along the centre of the tyre, and off-road style grips on the edges. Because of the round profile, when on hard surfaces the tyre behaves similarly to a road tyre, but, on soft surfaces, the tyre sinks a little bringing the knobbly grips into play and preventing further sinking and giving decent traction.

My advice would be “if in doubt, get the widest hybrid tyre that fits in your chosen frame”.

Question 5 — Brakes

This one was much more complicated in the past with lots of different mechanisms and pad-materials to choose from.

Today, things are much simpler IMO — hydraulic disk brakes, period!

Nothing else will give you even close to the same consistent, controlled, and powerful braking. Hydraulic disk brakes work when wet, and not only do they give you very powerful braking force with minimal effort, they also give you finger-tip control with a very smooth transition from gentle braking all the way through to full lockup.

Note I keep saying hydraulic disk brakes, just having disks is not enough, they must be hydraulic! Cable-operated disk brakes are just awful in my experience!

Question 6 — Gears

Question 6A — How Many?

Contrary to what you might think, what matters is not quantity, but range! The reason the number of gears has been steadily increasing over the decades from 5 to 12 to 21 and on up to 27 is not because more is better, but to cover a wider range from tiny climbing gear to massive high-speed gear.

Modern mountain and city bikes will have multiple cogs on the centre axel at the pedals, and multiple cogs on the rear axel. The number of gears you have is the product of the number of cogs on the centre and rear axels. I.e. if you have three front cogs and eight rear cogs you have 3 times 8 is 24 gears. We tend not to try to label them numerically from 1 to 24, but instead refer to them as combinations of front and rear position where the front is labeled low for the physically smallest cog, medium for the middle cog (if there is one), and high the physically biggest. We label the rear cogs numerically with the physically biggest cog as 1. Small cogs on the front will give low gear ratios so each turn of the pedal will provide a lot of torque, but very little forward motion. These are climbing gears. The big cog on the front is the opposite, lots of forward motion, but very little torque. These are speed gears. Things are exactly reversed on the rear, physically big cogs for climbing, and physically small for speed. So, Low 1 will be your smallest climbing gear, and on a 24-speed bike, high 8 will be your biggest speed gear.

To re-cap, you want as big a range as possible between lowest and highest.

Getting that range by adding ever more cogs causes problems:

• more cogs means more gear shifting, which takes time and effort, and slows you down (you can’t apply any force at the pedals while shifting gears).
• the difference in size between rear cogs is quite small, so they tend to shift very quickly with minimal effort, but the difference in size between front cogs is much bigger, so they take much more time and energy to shift.
• chains deal with side-ways stress very poorly, so with three cogs on the front and 7 or more on the rear you put the chain under great pressure when you use the opposite extremes front and rear. This is called cross chaining and should be avoided.
• The more rear cogs you have, the wider apart the forks have to be, and the bigger your frame has to be.

For years now it was normal for all mountain bikes to have three front cogs and at least 7 rear cogs (i.e. 21, 24 & 27 speed). City bikes often had the same, though often they omitted the smallest cog on the front and had only six on the rear (i.e. 12, 14, 21, 24, & 27 speed).

In recent years a new trend has developed, particularly in the more opinionated mountain bike designs, add even more cogs at the rear, and remove one of the front cogs! The emerging new normal is 20 speed, 2 at the front and 10 at the rear. To ensure you still get the full range from tiny climbing gear to fast speed gear the ten cogs on the rear have a very non-linear profile, with the gap between the bigger cogs increasing with every cog.

The 2×10 design has some major advantages:

• you can access a massive range of gear ratios without shifting the front gear (remember, it’s slower and harder work to shift)
• because there are only two cogs in front, cross-chaining is not an issue, you can use all of your gears

There is one very big drawback though — you can’t fit 10 cogs into a slender frame, so this will never work for city bikes, or even more traditional mountain bike designs.

Question 6B — Gear Shifters

In the past there were many options for shifting gears:

• Simple gear levers
• Twist-grip shifters
• under-handlebar thumb and finger shifters (finger shifter towards you for shifting with the spring, thumb shifter away from for shifting against the spring)

These days it seems to be 100% thumb/finger shifters. This means you’re not choosing the big-picture design, but there are still things to watch out for:

1. While the finger shifter can never shift more than one gear at once, the thumb shifter can. Poor shifters will only allow one shift per thumb push, OK shifters will allow two, and good shifters three.
2. There is a lot of variability in the design of the display for showing the current gear. You want a clear design that’s easy to read. IMO that means no numbers at all, they just block your view, and the actual number doesn’t matter, you just need to see if you are in the middle, near an extreme, or at an extreme, so less clutter is clearer!
3. There is a huge range in build quality. If you cycle a lot, you will break the poorer quality shifters!

Question 7 — Safety Equipment & Accessories

• Lights — I’m a firm believer that you should have a front and rear strobe at all times of day, and good headlamps if cycling on unlit roads in the dark.
  • Modern lights are USB rechargeable, so much simpler and less wasteful than before.
  • Modern light also use LEDs, so their charge lasts much longer.
  • I really like the USB rechargeable range from CatEye. All the bikes in our house have CatEye mounts, so we can all use any light on any of our bikes as needed.
  • I strongly suggest having a spare front and rear light with you at all times should you run out of charge unexpectedly. I keep two white lights mounted on my handlebars (one on and one-off), and a spare rear light in my saddlebag.
  • I cycle with two rear strobes at all times — one mounted on the back of my helmet, and one under the saddle.
• A mountable pump is essential — it’s not a question of if you’ll puncture, but when!
• Similarly, a mountable bag (e.g. under the saddle, under the crossbar, on the handlebar stem) with a basic tool kit, a spare tube, and a basic first aid kit is an absolute must!
• A rear-view mirror. I simply cannot comprehend how it’s possible to cycle safely without being able to see what’s going on behind you! There are lots of choices including:
  • handlebar-mounted (I find these are by far the most effective, especially those mounted into the ends of the handlebars. This is the one I like best and use on all three bikes in our house: Zefal Dooback Bicycle Handlebar Mirror)
  • helmet-mounted
  • arm-mounted (I have one of these for when I borrow other people’s bikes — RearViz Wrist Mounted Cycling Rear View Mirror)
• If you ever cycle on greenways or other paths or trails shared by cyclists and pedestrians you absolutely need a bell to be a good citizen! You want it to be loud, clear, and not aggressive-sounding. I love these:
• It should go without saying, but in case it doesn’t — never ever cycle without a helmet
  • It’s vital your helmet be sized correctly and correctly adjusted for your head. A poorly adjusted helmet can be worse than useless, it can fail to save your head and break your neck instead!
  • Helmets have a use-by-date because the material degrades over time, do not use an out-of-date helmet
  • Helmets are designed to take damage to dissipate forces before they enter your head. If you take a spill and give your helmet a known you must replace it — that knock has probably damaged the helmet internally, compromising its ability to protect you in the future!

Some Ergonomics Advice

• The first time you buy a bike, get expert advice on frame sizing before making your purchase — at best the wrong size will be uncomfortable for you, at worst, unsafe!
• Especially the first time you buy a bike, get some expert help adjusting the saddle position. Once you understand what’s right and what’s wrong, and why, you can do it yourself, but it really pays to get that help initially! Again, at best a poorly adjusted bike is uncomfortable, at worst, it’s unsafe! You’ll have less control, and you could very well do yourself an injury purely from the poor ergonomics.
• Adjust the angle of your brake leavers and gear shifters so you can rest your fingers on the brakes without bending your wrist (that’s 45° down from horizontal for me).
• Consider buying a pair of bar-ends to give yourself a variety of hand positions for longer cycles. Also, to allow a straight wrist position by having your hands perpendicular to the handlebars. (You don’t need anything fancy, or even big, I like the small subtle ones from BBB: amazon.co.uk/… or in the US: Origin8 Compe Lite Bar End)

Bonus Tip

Don’t confine yourself to the big two brands (Giant & Trek) — there’s great value available from the lesser-known brands. In my experience, you’ll get one spec-level higher for the same price if you go off-brand. You just need to be sure the brand is trustworthy. The most trustworthy source for that would be people you know and trust, second would be the staff in a good bike shop, and third would be reviews in well-trusted publications of any kind.