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Tips from a Roving Bike Mechanic

Tips from Steve Gurney as a Roving Bike Mechanic Motatapu Mountain Bike Race

Motatapu Mountain Bike Race

Rough, wet and muddy mountain weather was inevitable after 9 years of fine and fast conditions.This year was a most excellent reminder to take back-up, clothing, gear and tools when adventuring into remote mountain terrain.

However, there were a few very grumpy competitors, annoyed with delays and queuing for the river crossings, but somehow they missed the point… Mother nature's mountains need an attitude of respect.

Darwinism, (natural selection), will probably silence these naïve (and that’s being polite) types, but unfortunately, in our nanny state of cotton-wool and bubble-wrap, it’s the poor race organisers that take the rap for their death. I’m now specialising my keynote conference speaking in this area, “Escape the cotton wool catastrophe, tips to regain your power and to breed smart people”.

Contact me, your next speaker, at

Here are some things I learned for bikers:

Roving bike mechanics were kept incredibly busy through the 2015 Speights Motatapu Mtb…. I know, because I was one of them.

There were dozens of broken and bent chains, many snapped rear derailleurs, dozens of brakes worn metal to metal, many punctures, gears jammed, broken seats, 1 lost seat and 3 bikes lost temporarily in the river!! And then of course there was the "chain suck”.

In addition to the broken bikes, there were dozens of "broken riders”, so worn out and fatigued that they could only manage to walk their bikes. But there was nothing much we could do on the day to fix “broken riders” except to patch them up with a big smile and a squirt of enthusiasm! My day as a roving bike mechanic highlighted some tips for riders:

Broken chains

The biggest problem by a country mile is always mangled and broken chains. How to avoid broken chains:

Gear changing

  • Plan ahead

  • Change into a lower gear before you need it

  • Reduce pedal pressure and

  • Change one gear at a time if possible.

Chains break when asked to bend sideways too much. They’re designed to bend sideways a little bit, but too much bend, too many gears at once, under too much pedal pressure will compromise their strength and eventually bends the side plate off the pin.

It’s time to be frank and honest… broken chains are mostly a rider problem. It’s the back half of the field that break the most chains, .. the less experienced riders.

The problem comes with attempting to change under full uphill load, and it’s usually when riders are trying to change too many gears in one push of the lever, half way up a steep pitch, under race pace pressure, crowded in by riders all around.

On a mechanical level, the chain is being asked to bend sideways as you change to another gear, and when a rider has full pressure on the pedals, the chain has to bend more suddenly then it’s designed to as it crosses over between the cogs. It’s worse when the rider tries to change several gears at once as the chain has an even bigger sideways bend in it.

Yes the Motatapu course has way more short, sharp uphills than most courses as it dips into streams and then back up quite steeply, but the real issue is that in a race, riders are exerting more pedal pressure to do a fast time, … (and of course our ego likes to be seen riding those tough bits rather than walking).

You’ve gotta be gentle and plan ahead for the hills that need gear changes. Change gear where it’s flatter, just before the hill, under less load and less urgency. If it’s a dip you’re going into, you can even change, in anticipation as you’re coasting down into the dip.

Don’t change gears whilst pedalling in the water at river crossings, because the sideways current force the rear derailleur into the spokes and snap it off. You'll be pedalling hard in the water which only makes it worse. Gear Choice

  • Choose gears that keep the chain as straight as possible

Don't use gear combinations that cross the chain from one side of the front cogs to the other side of the back cogs, for the same reason as above; avoid excessive sideways chain bend. Crossing like this makes the chain bend suddenly as it feeds onto the chain-ring. Gear ratios are designed so that there is an overlap in the ratios between the different front chain-rings, mostly for this very reason. Chain-suck The excess mud we had in the 2015 course exacerbated chain suck and the subsequent chain breakage. 90% of chain-suck is because of worn chain-ring teeth and a worn chain. It’s usually on the wee granny gear, front chain-ring. The chain gets pulled up between the chain-ring and the chain-stay of the frame as it leaves the chain-ring. It’s often not a problem until it gets muddy.

The best solution is to check for worn chain and teeth before the race and replace if necessary.

  • Replace worn chain-rings and chain

  • Keep your chain clean

  • On race day:

    • Change gear early and

    • Judiciously use a half back-pedal.

If it happens in the race, it’s possible to do a quick back pedal for half a turn, to clear the suck. Planning ahead and changing down before you get to the hill will substantially increase your chances of being able to rectify chain-suck with a back pedal.

As it’s usually only the small chain ring that chain-sucks try to use the other chain-ring/s as much as possible instead.

A clean (no clogged grease) and well lubed (oiled) chain will reduce mud clinging to it. In the race it’s often useful to wash the mud off the drive train (all cogs and chain) at river crossings.

You can buy devices that bolt on under the bottom-bracket to prevent chain-suck, and the good ones really do work! Fixing a broken chain: You can easily use a quick-link, purchased from your bike store. Make sure you buy the right one to match your chain, (number of rear cogs on your cluster) 8-speed, 9-speed, 10-speed etc.

Most of the time you will need to use a chain-breaker tool to remove the broken side-plate remainder of the link.

It’s much easier to turn your bike upside down to work on the chain, and create some slack in the chain by derailing it off the front chain-rings. Make sure you’ve threaded the chain back correctly around the front and rear dérailleurs, (it’s easy to thread the wrong way around some of the metal guides!)

You’ll need to leave both ends of the chain with just the inner plates. Remove the outer plates by pushing the pin out with the chain breaker tool.

Insert the 2 quick-link pieces, “69” style to join the chain, and tug on the chain to click into place. It’s much easier if you wash any mud and grit off (squirt water with your drink bottle). Remember if you’ve removed more than one link of side plates, your chain will be shorter, and you might not be able to use some of the gears that use the large cogs. Test which gears you can’t use before you start riding again (you’ll be able to watch the rear dérailleur cage extend forward to it’s max). Buy yourself a decent chain breaker tool and learn how to use it on an old chain that’s destined for the bin, BEFORE the race. Note: If you have no quick-link, it is possible to remove the broken and bent links and carefully use the existing pin, but you’ll need to skilfully leave the pin in the side plate that you’re keeping so that you can push it back in again. You’ll need to be extra careful not to push the pin right out with this method. Use the chain breaker tool or a sideways bend to free up the resulting stiff link. Practice this at home first!

Broken Derailleur

Derailleurs usually only break in the Motatapu when changing to a lower gear during a river crossing (the sideways current pushes the cage into the spokes) or when the derailleur has been bent inwards accidentally, thus it subsequently gets sucked into the spokes when changing to an easier gear.

Accidental bends can be from other bikes pushing against it during transport, or laying the bike over on its right hand side and the dérailleur is bent by some dirt or a rock for example. Get in the habit of only laying it against the left side. Sometimes or the lower stop screw needs adjustment to stop it hitting the spokes.

Either way, with the enthusiastic gear changes of race day, it doesn't take much of a fault in the dérailleur for it to get sucked into the spokes when trying to select the lowest gear, and then snapping it. Always do a quick check that your dérailleur changes into lowest gear ok before the race; in the race, be aware and careful the first few low gear selections, changing down one gear at a time. Keep riding by…. A snapped dérailleur is not the end of your ride if you've brought a chain-break tool and quick-link. You can make a single-speed!

Remove your dérailleur and put it in your bag. Tie or tape the remaining cable out of the way.

Choose a gear combination that leaves the chain in a straight line. It’s usually a middle gear on the rear cluster, and the middle front chain-ring (or if you have only 2 chain-rings use the smaller one).

Lay the chain into place around the selected gears and figure out how many links you need to remove to make the chain a firm fit.

Shorten and join your chain. It’ll be much easier to join if you take the wheel out.

Remember not to use your front dérailleur once you've made a single speed.. (out of habit)!

Tyre Punctures

Choose the right tyre pressure and practice fixing flatties at home.

Choosing a tyre pressure

Flatties in the Motatapu are usually pinch flats (“snake-bites”) from not enough pressure in the tyre when going fast over rocks.

More pressure keeps the tyre away from the rim when it gets a hit from by a rock. But too much pressure makes for less grip in slippery conditions and a rougher ride. (Lower pressure makes for better grip in slippery conditions).

It will also depend on how many "pies you’ve eaten" and the profile (fatness) of the tyre. Heavier riders need more pressure.

As a very general rule, for the Motatapu, I like around 30 to 40 psi for a 75 kg rider. If it’s muddy like 2015, maybe 25 to 30 psi. Practice fixing punctures

I was amazed how many riders didn't know how to fix a puncture, didn't know how to use a tyre lever, or use the pump!

Practice before the race is a worthwhile investment!

Make sure your spare tubes are intact by testing them full of air overnight.

Also make sure they’re the right valve type and diameter for your rims. You’d be surprised how many spare tubes on race day didn't match!

Know how to use your pump or CO2 system. Yes, waste a canister! Tubeless tyres are becoming more and more prevalent now and they are generally immune to snake-bite punctures.

Brake failure

In muddy, gritty conditions, brakes will wear much more quickly, especially if you have rim brakes as the rims are constantly picking up grit to grind the pads. Disk brakes wear much less.

Either way, it’s common sense to check you have enough wear left before a long race like the Motatapu.

If in doubt put in new ones before the race.

If you’re using rim brakes, make sure you know how to adjust them as they wear. It’s a simple wind-out nut system on the brake levers, but you’ll need to make sure the cable is adjusted in enough for you to have the full range of the thread for race day.

Be Creative

One of our GurneyGoo enthusiasts emailed us how he used duct tape, GurneyGoo and a lot of creativity to finish his race despite losing a wheel bearing. (GurneyGoo is primarily designed to prevent skin blisters and rubbing!) Here's his story:

"It's not obvious in the pictures, but you can see the duct tape which covers the side of the axle.

Basically the bearing on one side of the wheel was just gone! So it was carbon on aluminum...

To fix it we just filled the space of the bearing with as much GurneyGoo as possible and closed the space with duct tape.

This fix lasted more than 100km first at "low" speed then gradually increased as the fix was just working perfectly. We finished one last 50km section without touching it... fearing we would screw-up the fix!

It saved our race and allowed us to finish in 11th position."

Hope to hear from you soon! Charles R'ADYS Team Switzerland

Prior Planning and Preparation Prevents Piss-Poor Performance

Planning time is a fantastic investment. In an adventure like the Motatapu, it’s not “if” you get a breakdown, it’s “when”.

Adventure has uncertainty and risk at it’s definitive soul. What truly makes adventure successful is your attitude to being adaptable. Be smart, be a thinking athlete.

Steve Gurney Adventure athlete

For Steve's great sports products go to:

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