Bicycles can carry astonishing loads, but there’s a limit to the amount you can pile on the bicycle itself.That’s where trailers come in. Living without a car, we’d be severely disadvantaged without a bike trailer – they are wonderful things. Alexander usually trailer- bikes to school these days, but in a typical week, our trailer still ferries heavy loads to the local tip, recycling to the bottle bank, collects shopping from the town, meets rail passengers carrying a spare folder, and numerous other tasks. It’s hard to say how many miles it does, but it’s probably two-thirds of our total electric bike mileage.We use a two-wheeled trailer exclusively – they’re easier to hitch and unhitch than a single-wheeler, carry more and can be wiggled through surprisingly small gaps.

Which trailer?

We’re great advocates of child trailers for all purposes, partly because they keep sleepy motorists awake. As a general rule, cars will give a child trailer a wide berth – we’ve certainly had fewer ‘incidents’ with a trailer attached than riding without.

The best all-round designs fold quickly, carry two children plus a couple of shopping bags, or 40 to 50kg of freight. Many such trailers exist.We’re still using a US-made Winchester of 1997 vintage (better known today as the Kool Stop Original Mark 2). These cost nearly £300, but there are a number of Far Eastern alternatives for less than £100.The cheaper trailers can be heavy, but if you don’t expect to lift it, that may not matter.There are an increasing number of freight-specific and dog-specific trailers available too – worth considering if you only expect to use a trailer for one task, but a child-trailer does most things quite well.

For public transport, light weight and compact folded size are the primary requirements. By far the best is the little Burley Solo which used to weigh just 7.3kg (16lb), but is probably a little heavier in its new guise (tinted windows, etc).The Solo is small enough and light enough to take just about anywhere and has no real competition, but for buses, in particular, do use a bag or cover. Bus drivers and railway guards can refuse to carry trailers if they think they might be a nuisance. Enough already – for a full list of all the trailers on the UK market, see our web site www.atob.org.uk

Common sense

The use of trailers with motor vehicles is heavily regulated, but surprisingly, cyclists are free to pull any weight on one, two… even a train of trailers, provided they are reasonably sensible about it. Common sense suggests a few basic rules.

It stands to reason that the towing bicycle should be in good condition. Brakes must be powerful, but not overly fierce, and the wheel, steering and suspension bearings must be free of play (looseness to non-engineers).The extra stress from a laden trailer can turn an old, but apparently rideable, bicycle into a wobbly jelly, so do check the machine over carefully.

Power assistance makes a great difference to the viability of pulling big loads in hilly areas.With muscle power alone, it’s deceptively easy to tow your own weight or more on the flat, but the slightest gradient will knock your speed back to a walking pace. Even limited power assistance can make a big difference – for years we used a Zap friction- drive kit to help pull big loads, and these days our heaviest trailer-fulls (primarily A to B magazines from the printers and to the Post Office) are shifted behind our Giant Lafree. This isn’t the most powerful electric bike around, but for towing you need slogging ability rather than outright performance.The same applies to muscles and indeed diesel engines.

Many types of tow-hitch exist, but not all are up to dealing with heavy loads.The least satisfactory design for heavy hauling is the seat post hitch, and as a general rule, the higher the connection, the worse it gets. As the trailer pulls back and forth and from side to side, this type will try its hardest to push you off the bike.We’ve towed unlikely weights with the wrong type of hitch fitted in the wrong place, but this is something of an acquired art.

In our experience, a hitch that mounts on, or close to the rear axle is the best kind, and our favourite is the Burley ‘alternative hitch’, available in quick-release or hub gear variants.These are quick and easy to swap from bike to bike, rigid, and easy to use. Other good hitches exist, such as the Weber, but look for something that allows movement in all planes without flexing. Some use a spring or flexible tube, which can work well with light loads, but may oscillate or ‘snake’ from side to side at speed with heavier loads. As with a car, you generally don’t discover that your ‘outfit’ is prone to snaking until you’re travelling fast enough for it to be a problem. If oscillation gets out of hand, particularly on a corner or while braking, the towing vehicle can be flipped off the road.

The best way to prevent calamities is to load heavy objects as low down, and as close to the centre of the trailer as possible – preferably just in front of the wheels.The idea is to have a small percentage of the trailer load supported by the rear of the bike, which helps to improve adhesion when cornering or braking.Too much weight may cause the tow-hitch to bend or flex, which can start the trailer snaking.Too little – or worse still, negative weight (a load behind the trailer axle) – may cause the rear wheel of the bicycle to leave the ground. In motoring terms, the general rule is to put 10% of the trailer weight on the tow hitch, and that sort of ratio is about right for a bicycle trailer too.

Another cause of instability is a long load. Most trailers will safely carry 40kg packed tightly in the middle of the vehicle, but try towing 40kg as a pile of three-metre timbers, and most bike trailers will become very unstable. If you intend to carry long loads (such as a canoe) on a regular basis, you’ll need a trailer with wheels further back than normal and a very rigid hitch – this combination will put more weight on the back of the bicycle, which is inconvenient, but generally more stable.

…a 33kg payload – two smallish children or quite a hefty supermarket shop…

Maximum weight

For cars, the safe maximum weight for an unbraked trailer is considered to be half the weight of the towing vehicle, and for most purposes this is a useful guide to the weight a bicycle can tow in safety. If we take a bicycle and rider weighing 90kg, the total trailer weight should be kept below 45kg. Assuming a trailer weight of 12kg, that leaves us with a 33kg payload – two smallish children or quite a hefty supermarket shop.With a trailing load of half the rider/bike weight, you should barely notice the trailer is there, provided you take account of the greater stopping distance, width and lack of acceleration when pulling out into traffic.

We regularly tow a lot more with our long-suffering Winchester – up to around the same weight as the rider and bike – and with a bit of care, anyone can do the same.With a trailing load of 90kg, you need to read the road with some care. Riding uphill will always improve stability, because the tow-hitch is pulled straight and rigid.Without power-assistance, hill-climbing can be painfully slow, but you’ll get there in the end with the right gearing.

Going downhill or braking (worst of all, both) is more complicated, because now the trailer is trying its hardest to overtake, and if over weight or poorly balanced, it may begin to oscillate. Fortunately, you’ve put the load just forward of the axle (you did remember to do this, didn’t you?), and this carefully positioned load allows you to make heavier rear brake applications without skidding. By contrast, the front brake should be used with real caution, because a front brake application will take weight off the back wheel. Similarly, keep your bottom firmly rooted in the saddle to put your weight over that crucial tyre contact patch.

…Children should be…instructed not to stand up and wave at passers by…

As a general guide, loads of 50% to 100% of the bike/rider are permissible with care, but beyond that, you’re on your own. In theory, a bicycle trailer can be fitted with over-run brakes just like a large car trailer. This would make heavy loads safer, but we’d still advise keeping gross weight below that of the rider and bike.

Finally, when you pull up at journey’s end in front of an appreciative crowd, do remember that the load may have shifted, turning a positive towbar weight into a negative one.This is fine until you hop off, causing the rear of the bicycle to leap up and everything to fall into a heap.

Cornering

 

As most bicycle trailers are designed for the litigious US market, manufacturer’s advice can sound extremely cautious.Take no notice – in many years of doing stupid things with over-loaded trailers, we’ve never, ever so much as lifted a wheel on a corner. Obviously common sense plays a role here. Avoid clipping kerbs with the inside wheel whilst cornering hard, in fact, avoid bumps generally. Children should be strapped in, or at least instructed not to stand up and wave at passers by. As roll-overs are rare, the primary purpose of a child safety harness is to keep the occupants still, making the trailer (and children) easier to handle. Do the same with freight – we use a pair of small 25mm ratchet straps, designed for car roof-rack or motorcycle loads. Bind everything down firmly, because if it can move, it will fall over or blow off at speed. Always check the and recheck after a mile or two if going any distance.You are entirely responsible for the load, and despite the lack of cycle trailer legislation, if the police really want a conviction, they can draw on a number of archaic laws from the days when penny-farthings frightened the horses.

…even the best trailers come with nasty cheap tyres that attract thorns like magnets…

If you’re not familiar with trailers, it’s worth practising riding techniques before venturing out, especially with children on board. Road positioning will be slightly different to normal, and you’ll need a lot more room to clear kerbs and posts.Try riding with a critical companion behind to give a running commentary. As a general rule, a well made and properly loaded trailer will do anything the towing bike can do in perfect safety.

Bumps & Rebounds

Cyclists are hard-wired to avoid pot-holes, or lift their weight out of the saddle if a bump is unavoidable. Believe it or not, it wasn’t until Alexander was old enough to complain that we realised the trailer occupant was unable to see the bump and thus unable to brace himself.We made life easier by fitting suspension – the previously rigid Winchester axle now pivoting against the spring force of a pair of bungee cords. Although rather crude, this system has excellent anti-roll characteristics (‘proper’ independent suspension would allow the trailer to lean outwards when cornering) and gives plenty of suspension movement. Manufacturers please take note and listen to what children are saying.The same applies to dumb loads. Carry a laptop in an unsuspended bicycle trailer and you’re asking for trouble. Place frail items on cushions, and lower the tyre pressures…

Another lesson we took years to absorb is that very light trailers require very little tyre pressure. Forget what it says on the side of the tyre – choose a pressure that will allow the tyres to absorb the worst bumps without going so low that the trailer begins to ‘wallow’ or becomes hard to pull. For a very small child, you may be looking at a pressure too low to register on the gauge. If you’re carrying gran home from the pub, you’ll need maximum and a bit more. And do try to remember just how boring a long trailer ride can be. As a cyclist, you can see over hedges and round corners, but the occupant of the trailer sees nothing but wheels passing by, which can become tedious very quickly. Alexander can survive a maximum of about an hour and a half without a break. A radio or cassette player works wonders, but don’t overdo the endurance thing.

One final point – even the best trailers come with cheap nasty tyres that attract thorns like magnets. Punctures are much easier to deal with on a stub axle (the tyre can be slipped straight off), but it’s still worth fitting decent hard-wearing tyres. As a last resort, a lightly loaded trailer can be ridden for miles with a flat tyre, ride too harsh.

Safety equipment

You may feel strongly to the contrary, but we’ve never used trailer flags.The annoying fiddly bits take ages to put together, the shaft whips about, threatening to thwack pedestrians, and there’s quite an increase in drag. Our general view is that flags are more trouble than they’re worth. On the other hand, we’re very strict about reflectors and lights – a trailer should have two well spaced reflectors and at least one powerful LED rear light on the offside (away from the kerb).The slim and ultra-bright Cateye LD600 is perfect. Twin lights are better, of course, and it’s quite legal (and probably advisable) to use flashing LEDs.There’s a theory that twin lights could be confused with the lights of a car much further away, but this may be a modern myth. Use light(s) at dusk, during heavy rain and any other time you feel vulnerable. If you habitually tow a large trailer after dark, there’s a good argument for fitting a front-facing white LED on the offside too.

Which bike?

You can tow almost any sort of trailer with almost any sort of bike, but some combinations can be hard work.When we had nothing more suitable, we pulled our big heavy home-made trailer with an old (and poorly braked) Brompton L3, using a hitch right under the saddle. No one ever fell off, but hills were hard work.These days, we generally use the Giant Lafree for heavier work, but it very much depends where you live. An electric-assist bike makes hills and road junctions a lot easier, and of course, safer.

Key trailer stockists & distributors

5-in-1 Orbit Cycles tel 0114 275 6567
Bike Hod Two Plus Two tel 01273 480479
Burley Fisher Outdoor Leisure tel 0208 805 3088
Chariot Amba Marketing tel 01392 840030
Christiania ZERO tel 020 7486 0379
Mission Mission Cycles & Components tel 01622 815615
Phillips Raleigh Parts & Accessories tel 01623 688383