In this maintenance special, e-mountain bikers will find tips from professional biker Andi Wittmann and EMTB author Christoph Malin. The two experts explain the most important steps for workshops and tours.
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The sparrows are whistling it from the rooftops! E-bikers are known to ride a lot and enjoy it, and the material is definitely not spared. Quite a few e-MTBs have twice the mileage of normal bikes in just one summer and autumn.
Brake pads melt away like butter in the sun, chains and sprockets wear out like in fast motion, and tyres also lose their treads at record speed.
The E-MTB is a highly technical piece of sports equipment with complex mechanics and electronics. Careful handling, care and regular maintenance of the bike are necessary to ensure that it functions perfectly, even with intensive use.
A specialist dealer can of course help with complex problems or software updates, but end users can do a lot of the work themselves - even an electronically powered bike is not rocket science. Regular maintenance minimises wear and tear and allows any aches and pains in the material to be detected at an early stage. And know-how is also required on tour if you want to help yourself with technical problems.
Photo: Christoph Malin Professional biker Andi Wittmann shows how to get your eMTB back into shape quickly and easily in the workshop.
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You can find these tips in this maintenance special for EMTB:
1 Problem areas 1.1 The neuralgic points on the E-MTB
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2 CARE 2.1 Clean thoroughly
3 Maintenance 3.1 Front sprocket 3.2 Chain check 3.3 Derailleur hanger and rear derailleur 3.4 Cassette 3.5 Brakes 3.6 Fork, shock, seat post 3.7 Headset 3.8 Cockpit 3.9 Tyre check 3.10 Battery and efficiency 3.11 Tools
4 Trouble Shooting 4.1 Fault table 4.2 Defect on tour
Photo: Markus Greber You can download this article and the entire EMTB 1/2017 issue from the EMTB app (iTunes and Google Play ) or reorder the edition in the DK-Shop .
1 PROBLEM ZONES
E-mountain bikers are extremely frequent riders. This increases wear and tear and the maintenance intervals become shorter. Regular checks and care help enormously.
1 RITZEL FRONT The performance of the E-MTB stands and falls with the front sprocket. Regular inspection is therefore essential. With the right tools, changing to a smaller sprocket is not a major issue.
2 CASSETTE E-MTBs have to shift twice as fast, and the forces involved are immense. Tooth failure or bent sprockets - it's worth keeping an eye on this.
3 TAX RATE The environment is not kind to headsets - constant shaking from above and below loosens even the best of the best. Regular inspection helps to prevent damage to the bearings.
4 ACCU Batteries should be handled correctly in operating mode, but also stored correctly - this is the only way to ensure long-lasting performance. A few simple tricks can help.
5 CHAIN Always this tugging! The chain tension on an E-MTB is many times higher due to the motor support and the chain is exposed to enormous forces. Regular lubrication works wonders here.
Photo: EMTB Magazin
6 BRAKES Brakes, brake pads and discs are under constant stress on E-MTBs. You should therefore take a close look at the wear on the stoppers from time to time.
7 COCKPIT Not only frequent riders should pay attention to the details in the cockpit. Small, sensible changes can improve performance - and save a lot of energy on tour.
8 SHELL Rock contact undesirable. Have you ever wondered if your derailleur is cracking even though it has worked perfectly up to now? The derailleur hanger was usually bent by a knock.
9 FORK / DAMPER Regular cleaning helps enormously to avoid costly wear and tear. The sliding surfaces and seals of the damper elements in particular need your care before and after the ride.
10 SEATPOST On tour and on the trail, the seatpost should always work perfectly, nothing is more annoying than dropper posts that get stuck. They need maintenance and regular care.
11 TYRES The market still only offers a few special tyres for e-mountainbikes. Normal MTB tyres therefore usually wear out very quickly on pedelecs, so regular checks for wear and damage are very important.
12 CABLES / ELECTRONICS A regular check of the external cables for breaks or other damage protects against unpleasant surprises. Malfunctions on tour can be a real spoilsport.
2 CARE
Modern e-mountainbikes can withstand just as much as their analogue counterparts. However, regular cleaning of sensitive parts such as gears, suspension and brakes also keeps wear to a minimum.
It's often the little things that make the difference. A little sand, a few splashes of dirt, a few droplets of oil loss, a fine crack in a seal. The result: sand in the gearbox in both senses of the word. Suspension elements in particular are precision mechanics. They need to be looked after and cared for if they are to do their job properly. So you can only wonder how many bikers set off on a tour with dirty suspension forks and dampers. In the end, the biker is penalised twice: firstly, the function of the fork and damper is impaired, and secondly, the half-life is shortened: dirt not only impairs the sliding properties of the suspension elements, over time the dirt also migrates past the dust seals into the area of the sliding seals, oil scraper rings and dip tubes. Emery where it shouldn't be, namely where filigree mechanical parts are moved thousands of times. Increased wear is inevitable. This can go on for one or even two seasons, but in the end you pay the bill - when sealing parts on forks are so worn that air or oil escapes. Or when sand grinds in the drivetrain until the sprocket, gears, chain and chainring are worn out.
2.1 CLEAN THOROUGHLY
Photo: Christoph Malin 1 Frame: First remove any coarse dirt from the bike outdoors using water, a brush and a hose. Be careful with high-pressure cleaners, especially at petrol stations: the higher the pressure, the greater the distance to the bike must be! Then clean in detail with a sponge and bucket. Photo: Christoph Malin 2 Fork: If the dust seals are clean, the fork is fine. Remove dust and dirt with a cloth. Do not use degreasers or aggressive cleaners. Some manufacturers also advise against treating the stanchions (light-coloured) with special penetrating oils. Our tip: Turn the bike upside down - this allows the fork oil to run towards the seals. You can also grease the seals from the outside with a little fork oil, then compress the fork a few times. Remove the remaining oil with a clean cloth so that no dirt sticks to it. Photo: Christoph Malin 3 Damper: The damper also likes it when the area around the dust seal is clean. Proceed in a similar way to the fork: use a clean cloth to remove dust and dirt. You can apply some damper oil to the damper piston and seal. Then compress the shock a few times by applying pressure to the saddle from above. Otherwise, as with the fork, turn the bike upside down. Photo: Christoph Malin 4 Charging port: The on-board charging ports of the batteries are covered on all E-MTBs. When cleaning the bike, you should make sure that the covers are closed. If water does get on them and, in the worst case, on the contacts, remove the battery, dab off the moisture and leave the bike to dry in the sun. The bikes are generally splash-proof. If the charging port is closed, nothing can happen even if you ride through a puddle or in a downpour. However, it is advisable to treat the contacts once a year with contact grease (available from electronics accessories retailers). Photo: Christoph Malin 5 / 6 Dry and clean the chain: Wipe the bike dry with a soft cloth. This is a good opportunity to check the frame and attachments for cracks and other damage.Photo: Christoph Malin Now clean the chain: Hold a cloth around the chain and turn the crank backwards - this allows the chain to slide through the cloth and be cleaned. Photo: Christoph Malin 7 Lubricate the chain: You must lubricate the chain after cleaning. Use the cloth to prevent chain oil from getting onto the brake disc when spraying. Spray the chain oil onto the inside of the chain while turning the crank so that the oil is distributed over the entire length of the chain. Once you have applied the chain oil, turn the crank and shift through all gears several times. Then wipe the excess chain oil off the chain with the cloth. Ideally, you should lubricate the chain of an e-MTB before every ride. The drive is subjected to enormous strain on e-mountainbikes and regular lubrication reduces wear a little.
3 MAINTENANCE: Check wear, replace parts,
Adjusting the gears, suspension and cockpit, or replacing brake pads - you can easily do a lot of maintenance work on your e-mountainbike yourself.
3.1 FRONT SPROCKET
Replacing the front sprocket is not rocket science and makes sense if the original gear ratio does not meet individual requirements. the market now offers tuning accessory sprockets of all kinds.
Photo: Christoph Malin 1 Remove the crank: When do you remove the front sprocket? To check the condition of the sprocket after a season or to improve the gear ratio of the E-MTB. If you ride a lot of steep climbs in the mountains, you will want to use smaller accessory sprockets at the front. Please note: Only with the 2017 Bosch software is it possible to replace the sprocket without reprogramming the gear ratio at a specialist dealer. If you are not sure, have the update installed by your dealer. To remove the crank, use the Allen key to open the crank bolt anti-clockwise. In the picture, a puller is integrated in the crank, for cranks without one you need a separate crank puller.Photo: Christoph Malin 2 Open with Bosch spider tool: The Bosch tool available from specialised dealers has two directions of rotation. To open the lock ring, turn the tool to the right, but then the motor freewheel will also run. However, in our experience, the lock ring can be opened with little effort on many bikes. If not, fix the opposite crank (don't worry, the force is applied to the steel reduction gear, it won't damage the motor). Alternatively, unhook the chain and fix the sprocket with a chain whip.Photo: Christoph Malin 3 Open the pinion: Now carefully unscrew the lock ring anti-clockwise from the thread. Pay attention to the O-ring behind the lock ring thread, note its position and carefully remove the ring. The picture shows an 18T Haibike sprocket guard, which can now also be removed.Photo: Christoph Malin 4 / 5 Replace the sprocket: Remove the old sprocket and replace it with the new one (in the picture a 15T FSA). Carefully replace the O-ring. Screw the lock ring back onto the thread.Photo: Christoph Malin To secure the sprocket, fit the Bosch spider to the lock ring and turn it anti-clockwise. Hold the crank firmly or fix the sprocket with a chain whip. Re-attach the chain. The chain must now be cut to length again for a smaller sprocket. Photo: Christoph Malin 6 Securing the crank: A common mistake when fitting the crank after replacing the sprocket: The crank bolt is not secured with threadlocker. To do this, apply threadlocker to the thread on the inside of the axle.Photo: Christoph Malin 7 Crank assembly; Andi Wittmann's trick: To prevent the torque from becoming too high, the crank and Allen key are not twisted against each other. Instead, he fixes the crank to the chain stay with his left hand and tightens the crank Allen key with his right hand.
3.2 CHAIN CHECK
As a rule of thumb, the chain should be changed every 2000 kilometres on an e-MTB - otherwise the cassette and sprocket could be damaged. A chain gauge helps to determine the wear of the chain.
Check wear
Even if there are now special E-MTB chains: They are exposed to greater loads due to the high chain tension forces and to heavy wear due to the generally high mileage. What happens if the chain is worn and is not replaced? It wears into the sprocket and cassette to such an extent that these two parts also have to be replaced the next time the chain is replaced - an expensive affair.
When should the chain be replaced? That depends on the chain gauge - check the information on the product. In our workshop, we use a ProLink chain gauge from ProGold. A chain replacement is due at an indicator of 7 to 8. Time to change the chain, Andi!
Photo: Christoph Malin
3.3 DERAILLEUR HANGER AND DERAILLEUR
Off-road, a bike is constantly in close combat - with rocks, branches and undergrowth. The derailleur hanger can quickly become bent. If the chain is reluctant to change gears or the chain rattles while riding, it's time to adjust the gears correctly.
Photo: Christoph Malin Bent derailleur hanger: If you aim at the derailleur pulley exactly from behind, you will recognise that the derailleur hanger is bent. You can now try to bend the derailleur hanger back by applying lateral pressure. This may not work with very stable derailleur hangers. Then the only solution is to fit a new derailleur hanger. So: On long tours, a spare derailleur hanger belongs in your rucksack.Photo: Christoph Malin Set the lower limit: Is the chain rattling on the smallest sprocket? Then use the inner limit screw (on Sram drivetrains) to adjust the stop on the small sprocket so that the upper guide roller of the cage is directly below the smallest sprocket. Turning the screw to the left moves the cage to the outside right and vice versa.Photo: Christoph Malin Adjusting the upper sprocket: It gets really annoying when the chain falls between the large sprocket and the spokes. To set the stop correctly: Shift to the largest sprocket and turn the outer limit screw until the guide roller is exactly below the large sprocket. Turning the screw to the right limits the cage to the left and vice versa.Photo: Christoph Malin Set the wrap: Use the so-called B-screw to adjust how far the chain wraps around the respective sprocket on the cassette. The distance between the guide roller and the large sprocket (red circle) should be 5-6 millimetres (Sram). However, the specifications differ from manufacturer to manufacturer (check the gear manufacturer's instructions!). Photo: Christoph Malin Adjust the cable tension: After the first 50 kilometres, the shift cable has stretched and the shifting system needs to be readjusted. Use the cable tension screw on the shift lever to increase or decrease the tension on the shift cable. To adjust, shift to the smallest sprocket and from there shift forwards and backwards to second and third gear. Photo: Christoph Malin Fine adjustment of tension: The tension should only be so high that the chain climbs smoothly onto the next sprocket. If the chain rattles when shifting down, reduce the tension. Shift through all gears one after the other and adjust the gears by reducing or increasing the tension on the gear lever using the knurled screw.
3.4 CASSETTE
On an e-mountainbike, the entire drivetrain is subject to particular stress. The cassette should therefore also be cleaned regularly, inspected for wear and replaced with a new one if necessary.
No matter what gear ratio you ride - an E-MTB accelerates more than twice as fast as a normal mountain bike, and gear changes also take place at shorter intervals. In order for the cassette to fulfil this demanding task flawlessly, it must be kept in perfect condition. In other words, the teeth must not be too worn and the spaces between the sprockets must not be dirty.
Photo: Christoph Malin CassettePhoto: Christoph Malin Check the cassette: Bent sprockets are rather rare, but can occur on E-MTBs. To do this, rotate the cassette and visually check that everything is running smoothly. The teeth in the shifting lanes are particularly stressed over the course of thousands of shifting operations.Photo: Christoph Malin To check the wear, it is best to compare the cassette with a newer one: Are the tooth gaps wide open, or are the climbing ramps or teeth badly worn? If you want to know exactly: Rohloff offers a sprocket tester, the Rohloff-HG Check.
3.5 BRAKES
If you grind the pads down to the backing plate, you also risk damaging the brake discs. So: check regularly, change in good time! We'll show you how using a Magura as an example.
Photo: Christoph Malin Replace brake pads: Check the brake pad wear regularly, especially before you set off on a long tour. Once the brake pads have worn down to the backing plate, they can tilt and damage the disc. You should not go below 0.5 millimetres of remaining brake pad. Photo: Christoph Malin Push back 1 piston: The wear adjustment mechanism ensures that the pressure point on Magura brakes always remains the same despite pad wear. For this reason, the pistons must first be pressed apart when replacing the pads. This is best done with the old pads still in the brake. Never push back the sensitive pistons directly! Use a screwdriver to push the pads apart and the pistons back. Tip: This is also the zero condition for ventilating the brakes to prevent overfilling. Photo: Christoph Malin 2 Press out the brake pads: Loosen the locking screw and press on the small retaining lugs of the pads from the rear of the brake calliper, now push the pads through to the rear so that the retaining lugs pass the brake calliper.Photo: Christoph Malin 3 Remove the brake pads: If the magnetically held brake pads cannot be removed easily at this point, the pistons may not have been pushed far enough apart after all. In this case, repeat procedure 1 and try again. If it still does not work, remove the brake pads individually.Photo: Christoph Malin 4 Clean the brake calliper: Braking produces brake pad abrasion, this fine dust settles in the area of the brake calliper and on the fork. This dust can become caked on due to the heat generated. Clean the brake calliper thoroughly with a dry cloth, but do not use cleaning agents.Photo: Christoph Malin 5 Insert new brake pads: Now push the new brake pads into the brake calliper one by one in reverse order. This can sometimes be a little awkward. Keep calm and it will work. You can read about which brake pads brake best and which wear the least in our sister magazine BIKE, in issue 4/2017 .Photo: Christoph Malin 6 Set the pad distance: Normally, with the piston in the zero position, this completes the pad replacement. If the pads are a little too close together, you will need to do it again. To do this, take the original transport locks supplied with the brakes and press them between the pads.Photo: Christoph Malin 7 Check the disc thickness: Before refitting the wheel, measure the minimum thickness of the brake disc. This is 1.8 mm for Magura. You can only determine the minimum thickness precisely with a caliper gauge. If the thickness falls below this value, the brake disc must be replaced. The same applies if the disc is clearly scored.Photo: Christoph Malin 8 Check the pressure point: With the front wheel fitted, you can now check the pressure point. To do this, pull the brake lever for a few seconds. If everything fits, have fun on tour! Otherwise, we recommend having the brakes bled by a specialist dealer. You can find a tutorial on how to bleed brakes yourself at www.bike-magazin.de, webcode #14299
3.6 FORK, DAMPER, SUPPORT
Forks, shocks and dropper post should be checked regularly: Do the bushings have too much play? Are there scratches on the stanchions? Are the suspension elements still tight?
Photo: Christoph Malin Check for scratches and leaks: Scratches on the fork stanchions (light-coloured in the picture) are not cosmetic defects - they can wear out the dust seals. Consequence: The system will leak. Special suspension service centres can polish out minor scratches. In the case of larger nicks, the fork crown must be replaced, which can be expensive. Check the current value of the fork in each individual case. Photo: Christoph Malin Check bushing play: If you ride a lot, your bike will eventually develop bushing play. Check the bushing play on the fork with the front brake applied and your thumb on the lower tube and stanchion. To check the bushing play on the shock (upper and lower shock mount), lift the bike up by the saddle. If it rattles, a fork or shock service by a specialist is necessary. The same applies to the dropper post.
3.7 TAX RATE
Even the best headset will start to wobble at some point, but it's best if it doesn't happen at all!
Photo: Christoph Malin Headset check: The headset is not only under constant pressure on normal bikes. Due to their slightly higher weight, e-mountainbikes put even more pressure on them! If the bike is used for too long with headset play, the bearings can be damaged in the long term. The following therefore applies: Check the headset regularly for play and adjust it if necessary. 1 Check play: With the front brake applied, place your fingers around the head tube and upper bearing cap and push the bike forwards and backwards against the braking resistance. Bearing play can usually be felt immediately. Of course, you can also check the same on the lower bearing. Photo: Christoph Malin 2 / 3 Adjust the play: To adjust the bearing play, open the stem at the shaft bolts. Then adjust the bearing play with the screw on the top cap and close the stem screws again. The headset is correctly adjusted when the handlebars can be turned without noticeable resistance when the bike is raised and the headset has no play.Photo: Christoph Malin
3.8 COCKPIT
Small cause, big effect. Small changes in the setting of the operating elements can significantly increase performance and fun on tour. Less manual force and easier operation are the result.
Photo: Christoph Malin Position the selector switch: Whether Bosch Purion or Intuvia, or the switches of other suppliers - for optimum operation, the selector switch for the support levels should be positioned so that you can reach both buttons intuitively with your thumb without having to change the position of your hand on the handlebar grip.Photo: Christoph Malin Distance to the handlebar: The distance to the handlebar is set using the Allen screw on the underside of the Purion. To do this, open the screw until the Purion can be moved on the handlebars. Once the desired position has been reached, it is advisable to tighten the screw only enough to prevent the switch from twisting in the event of a fall. Photo: Christoph Malin Positioning the brake lever: On 99% of our test bikes, the brake lever clamps are positioned directly on the handlebar grip at the factory - a deadly sin in terms of ergonomics. For ideal positioning, mount the brake lever clamp so far inwards on the handlebars that the index finger can comfortably pull the brake lever without the hand slipping too far out towards the end of the grip. Photo: Christoph Malin Seatpost remote: Up and down, again and again - on some tours, the telescopic seatpost rarely comes to rest. It's a shame when the remote lever is located to the left of the support mode selector switch. Then you like to lower the seatpost instead of switching to turbo mode. It is therefore better to move the seatpost remote (photo) to the right so that you can operate it easily with your thumb.
3.9 TYRE CHECK
As the interface between the bike and the ground, tyres are of central importance. This makes not only the choice of tyre model all the more important, but also the condition of the tyres: sidewall, tread and air pressure.
Photo: Christoph Malin Tread damage: A regular tyre check can prevent more serious problems. Cracked studs can tear off completely and half-driven thorns can be waiting to deliver the fatal blow. Therefore, check the carcass of your tyres after a ride. Photo: Christoph Malin Sidewall damage: Cuts and other damage to the sidewall - whether small or large - are particularly critical. Sudden loss of air can lead to dangerous driving situations.
3.10 BATTERY AND SURROUNDINGS
The battery is the fuel tank and energy source of the e-mountainbike in one and part of a complex system. Used correctly, the efficiency and service life of these power packs can certainly be increased. But everything else counts too. Here are the best tipsL
1 Cadence How to save battery power: Every motor has an optimum speed, which is available as cadence in revolutions/minute at the gearbox output. Bosch motors are most efficient at 80 rpm.
2 Total weight Optimising the pilot's weight also reduces battery consumption. It is therefore advisable to always pack your rucksack cleverly.
3 Switch more If you are lazy about shifting gears, you are wasting energy. To keep the motor revving and in good spirits, shift gears more often. Basically, the gear ratio should be adapted to the area of use, i.e. replace the sprocket and cassette if necessary if the factory setting does not provide enough power for alpine ramps.
4 Chassis setup On trails, a well-adjusted chassis minimises so-called impact and start-up losses and increases the efficiency and effectiveness of the engine by up to 30 %.
5 Translation Sram's EX1 is currently the ultimate in the alpine sector. The 12-48 cassette at the rear and a 14-speed sprocket at the front enable optimum cadence even on steep sections. This also saves battery capacity.
6 Tyre pressure The correct tyre pressure also minimises impact losses and rolling resistance. The best compromise between comfort and puncture protection depends on the tyre - the wider the tyre, the less air pressure is required.
7 Temperature As the ambient temperature falls, the performance of the battery decreases and the internal resistance of the battery cells increases. Use a battery thermal protection cover. Caution in summer: Never leave your bike in the blazing sun.
8 Shop First bring ice-cold (winter operation) or hot batteries (high summer) to room temperature before charging. A charging cycle is the complete charging of the battery with a single charge or two partial charges.
9 Bearings Store batteries in a dry place at room temperature (approx. 15-20 °C). For longer storage periods, the battery should be charged to approx. 50-60 %.
3.11 TOOLS
Our special doesn't need many tools. Apart from the Bosch spider for changing the sprocket, you should be able to find everything you need in a well-stocked bike workshop.
Photo: Christoph Malin RatchetPhoto: Christoph Malin Bosch spiderPhoto: Christoph Malin Bosch SpiderPhoto: Christoph Malin Chain gaugePhoto: Christoph Malin CaliperPhoto: Christoph Malin Medium-strength threadlockerPhoto: Christoph Malin Flat-head screwdriverPhoto: Christoph Malin Allen key set
4 TROUBLESHOOTING
Dou should know the most important error codes of Bosch e-bike motors in order to be able to initiate the right measures on tour.
4.1 ERROR TABLE
Via the internal engine diagnostics, a Bosch system is able to communicate its displeasure via an error code if something is wrong. Here are the best-known error codes from practice and the appropriate workaround.
Photo: EMTB Magazin Bosch e-bike motor error code table
4.2 EMERGENCY MANAGEMENT
The most important rule in the event of a defect on tour: stay calm and analyse the situation soberly - this is the only way to make the right decision. And that can also mean ending the tour and turning back.
1 battery key forgotten It's happened to everyone. The first battery runs out on a tour with a blistering altitude difference. You fish the second battery out of your rucksack ... and the key is ... at home. The only thing that helps is to weigh things up: How far is it to the next hut, is there a suitable charger there? Is dusk or a storm approaching? Then leave quickly. From now on, always leave the key in the same rucksack.
2 Sensor torn off Unfortunately, this also happens. A branch tears off a few spokes and the speed sensor. The tour is practically over, the agile e-MTB has mutated into a sluggish DH bike. The descent into the valley follows, preferably on a route that doesn't require much pedalling on the valley floor.
3 Battery runs out too early Switch to the lowest support level immediately, adjust the speed and estimate after a few minutes whether the range display makes it plausible to reach the tour destination, including a reserve for the return journey. Otherwise, proceed as for 1.
Photo: Christoph Malin in an emergency: Know how!Photo: Markus Greber You can download this article and the entire EMTB 1/2017 issue from the EMTB app (iTunes and Google Play ) or reorder the edition in the DK-Shop .
