SmartDrive MX2+ Review: Power Assist That Earns Its Place on a Manual Chair

The short version. The SmartDrive MX2+ is the most widely fitted rear power assist on manual wheelchairs in Canada. It extends daily range, it reduces the number of pushes a day costs, and it fits onto most chairs. Three things the marketing does not lead with matter more than any of that when you are deciding: one of its control components is under an active manufacturer recall, the unit is heavy enough that most people in the only published long-term study could not mount and dismount it from the chair unaided, and the funding route is different in every province. This review is built from Permobil’s own specification sheet, manual and recall notice, and from the published research, not from a test unit.

What it is

The SmartDrive MX2+ is a single-wheel power assist unit that mounts behind the rear axle of a manual wheelchair. A motor in the wheel propels the chair forward while the user steers and brakes on the handrims as usual. There are three ways to control it, and this is the part most write-ups get wrong: a wired SwitchControl button, which Permobil includes with every SmartDrive at no extra cost and which can be ordered with a mono jack port so an external switch or Buddy Button can be plugged in; a wearable, either Permobil’s PushTracker or the user’s own compatible Apple Watch or Wear OS watch; and, until the recall, a SpeedControl dial. With the wearable, a double tap of the hand against the handrim activates the motor, a single tap sets the coast speed, and a double tap then a brake stops the chair. All of this is set out in the SmartDrive MX2+ user’s manual.

Permobil states the intended user weight range as 30 to 331 lbs (14 to 150 kg), with a combined user and wheelchair maximum of 351 lbs (159 kg), and lists compatibility with wheelchair drive wheels of 22, 24, 25 or 26 inches. The manual gives a maximum speed of 4 mph (6 km/h) as the default setting, adjustable to 5.5 mph (8.9 km/h), and a maximum incline of 10 degrees (17 per cent).

The SmartDrive was developed by Max Mobility, a Tennessee company. Permobil announced its acquisition of Max Mobility on 27 December 2017, as reported by Mobility Management, and Permobil’s own recall page confirms that “Max Mobility was acquired by Permobil in 2017”. Max Mobility, LLC remains the establishment name on record with the US Food and Drug Administration for the device, which is why both names appear on the paperwork.

Buying it in Canada, and paying for it

Permobil does not publish a Canadian list price, and quotes vary with the mounting hardware your chair needs, so this review does not print a figure. Ask for an itemized quote that separates the unit, the attachment hardware for your specific chair, the control you have chosen and any wearable, and compare two or three dealers where distance allows. Permobil provides an order and quote request form through its dealers.

Availability in Canada is through Permobil’s dealer network, and the Permobil Canada dealer locator is the reliable way to find a fitter near you. Names change: the chain formerly trading as Motion Specialties now trades simply as Motion, and Shoppers Home Health Care now redirects to Wellwise, which does not list power assist. This is not an over-the-counter purchase. Permobil requires a documented training session with your dealer, with a signed SmartDrive MX2+ Training Certification listing the specific skills you have demonstrated, kept in your file.

Funding is provincial and it is not uniform, so the only honest advice is to confirm your own program’s rules in writing before you buy anything. One rule is near-universal and costs people the whole subsidy when they miss it: most programs require authorization before purchase, and buying first can forfeit the funding entirely. For veterans, Veterans Affairs Canada covers wheelchairs and power mobility devices under Program of Choice 13, Special Equipment; VAC states these benefits “must be prescribed by a VAC approved health professional and in many cases supported by the recommendation of another health professional”, and pre-authorization applies. Workers’ compensation boards and private extended health plans each have their own tests. Ask your occupational therapist to tell you which pot you are applying to, and what it requires, before the assessment rather than after.

Getting it on and off, and working it

This is where the honest picture and the marketing picture diverge most.

Mounting and dismounting. The only published long-term study of the SmartDrive followed six adults with spinal cord injury in Sweden over six months. In Permobil’s own summary of that study, every participant reported that the SmartDrive was heavy to handle, only one of the six could mount or dismount the device while sitting in the wheelchair, and that person still preferred to ask for help when someone was available. Four of the six could lift it in and out of a car. Six people is a very small study and it was done in a Swedish rehabilitation setting, so treat it as an indication rather than a rate. But it is the best evidence there is, it comes from the manufacturer’s own research library, and it points the opposite way from “manageable within the first few weeks”. Test this yourself, with your own chair and your own car, before you commit.

Weight. Permobil’s manual gives the SmartDrive itself as 13.2 lbs (6 kg) and the total assembly, including the attachment hardware, as 14.4 lbs (6.5 kg). That total is the number to use, because it is what has to come off the chair and into the car, and it is also the number Permobil says to add to your chair’s on-board weight when checking your wheelchair manufacturer’s maximum. Participants in the Swedish study said they did not notice the extra weight while pushing with the motor switched off; handling it off the chair was the problem.

Controls, and the choice most people are not offered. The wearable is not the only way to drive a SmartDrive. Every unit ships with a wired SwitchControl button included, which can be latched for steady power over distance or pressed for a short burst, and which is available with a mono jack port so an external switch, including a Buddy Button, can be used instead. Permobil also publishes a smartwatch compatibility guide listing Apple Watch 5 through Apple Watch 10 and Ultra models, and Wear OS watches including the Samsung Galaxy Watch4 through Watch6 and several TicWatch models, so the wearable can be a watch you already own rather than a proprietary band. If tap gestures are unreliable for you, ask specifically about SwitchControl and about the alternative MX2 and MX1 control modes; Permobil’s own training sheet tells the dealer to try those modes when the standard skills cannot be performed.

Charging. The battery stays in the unit. Charging is a magnetic connector that you move a rubber cap aside and offer up to a receptacle on the powered-off SmartDrive, which is a good deal easier for limited hand function than a plug. Permobil gives a full recharge as approximately three hours.

App and connection. The PushTracker app, on iOS and Android, is where settings, push tracking and firmware updates live. The wearable talks to the SmartDrive over Bluetooth and must stay within 25 ft (8 m); if the connection drops while the motor is driving, the SmartDrive deactivates and beeps. We have not tested the app with a screen reader and make no claim about it either way; if you rely on one, ask the dealer to demonstrate the app with your own assistive technology at the fitting.

Living with it: battery, wheel, service

Battery and range. The battery is lithium iron phosphate. Permobil rates range at up to 12.3 miles (19.8 km) on the level with no resistance, and gives a continuous theoretical driving range of up to 14.2 miles (22.9 km). Both figures come from testing with a 331 lb (150 kg) occupant, and Permobil states plainly that range, speed and the rest vary with the user, the chair and the driving conditions, so treat them as a ceiling rather than a daily expectation. Rated operating temperature is -25 to 50 degrees Celsius. We have seen no manufacturer or published figure for how much range Canadian winter costs, so this review does not give one.

Replacement and repairs. Permobil offers a two year warranty against manufacturing defects, limited to repairing or replacing defective parts, and it can be voided by modification or by use outside the manual. Batteries in any device are a wear part. Ask your dealer, before you buy, what a replacement battery costs, how long it is expected to last in your use, and whether your funding program pays for replacements or only for the first purchase. That last question catches people out.

The wheel is not a tire. There is nothing to inflate. The SmartDrive drives on a 7.6 in (193 mm) omni-wheel carrying 16 or 18 rubber rollers, and Permobil’s maintenance instruction is to check before each use that every roller still spins freely and has not developed flats or significant wear. The rollers can be replaced. In snowy places, road salt corrodes the roller bearings, and Permobil’s remedy is to spray lubricant on the bearings to extend their life, which is a piece of Canadian-winter maintenance nobody mentions at the fitting. Wipe the unit down with a damp cloth at least once a month.

Hardware checks. Permobil’s pre-use inspection list is short and worth learning: cracked plastic, worn or seized rollers, ripping rubber on the wearable band, missing or loose screws, an adaptive clamp that has rotated downward on a rigid chair, frayed cables, and metal shards collected on the magnetic charging receptacle. Any of those means stop and call the dealer.

Firmware. Permobil instructs users to connect to the app regularly and to update firmware before troubleshooting anything, because the fault may already have been fixed in a later release. The manual lists the error codes and what each one means, including the two that require a circuit board replacement.

Service reach. Service runs through Permobil’s authorized dealers, so how well you are covered depends on how close the nearest one is. Check the dealer locator for your own postal code before you buy, and ask what happens when the unit has to go away: who ships it, who pays, and how long you are without it. We have no published figure for average Canadian turnaround, so do not accept one from anybody who has not put it in writing.

The learning curve

The SmartDrive has a real learning curve that the marketing tends to understate.

The tap vocabulary. Getting the sequence right matters, and it is the reverse of what is often written down. Permobil’s training sheet has it as: double tap to activate the motor, single tap to set the coast speed, then double tap and brake to stop. The taps are made with the hand against the handrim with a stiff wrist, gently rather than hard, with about half a second between them, and the wearable shows red to confirm a good tap. Permobil tells dealers to have you practise single taps until you get them every time before you activate the motor at all.

Speed calibration. Setting the right speed for your chair, your body weight and the places you actually go takes iteration. The default speed is conservative; many users adjust upward over the first month as confidence builds. Going too fast in unfamiliar environments produces near-misses that erode confidence; the iteration is worth doing slowly.

Terrain learning. Hills, slopes, uneven sidewalks, and transitions (curb cuts, doorway thresholds, elevator gaps) require new physical skills. The SmartDrive’s forward propulsion behaves differently from rim-pushing on terrain; you have to learn to read the chair and the SmartDrive as one moving system.

Knowing when to switch it off. Permobil’s own training certification asks you to certify that you understand the situations where the power assist should be turned off entirely to stop it driving forward unintentionally: downhill slopes, going up or down curbs, climbing large sidewalk cracks, being in confined spaces, before handling either the SmartDrive or the wearable, whenever parked, and when transferring in or out of the chair. That list is worth committing to memory.

Three-month mark. Most users report that by month three, the SmartDrive is in muscle memory and the daily cognitive load is low. The first three months are real; budget for them.

What it changes about a day

Once it is on the chair and switched on, you operate the SmartDrive on your own. Getting it on and off the chair is the part that may not be solo, as above.

What the research found. In the Swedish six-month study, all six participants agreed afterwards that the SmartDrive increased their independence, their ability to move freely outdoors, and their participation in the activities they wanted to do, and that it was safe, easy to use and reliable. They described less need to plan a route before going out, less avoidance of slopes, and being able to manage long and steep hills and longer distances. Shoulder pain was the main reason the device had been prescribed. Findings on pain were mixed: a pain diary suggested some participants had less pain, less intense pain and less interference from it, and two reduced their pain medication, while those whose pain did not drop said its impact on what they could do had. Six participants, one Swedish rehabilitation centre, six months. It is a pilot study and should be read as one.

Why pushing load is the thing being managed. A 2021 systematic review and meta-analysis of 40 studies of wheelchair users, by Liampas and colleagues in Pain and Therapy, found a pooled prevalence of musculoskeletal pain at any site of 50 per cent (95 per cent CI 33 to 67), with shoulder pain the most common syndrome at a pooled prevalence of 44 per cent (95 per cent CI 36 to 52). Wheelchair users in that analysis were 5.8 times as likely to have shoulder pain as controls (95 per cent CI 2.7 to 12.2). Older age and longer duration of wheelchair use were the strongest determinants. The review is published here. That is the arithmetic behind every power assist conversation, and it is also why the same review notes that optimal adjustment of seating position may help prevent pain and should be taken into consideration in its own right.

Terrain, within limits. Permobil rates the SmartDrive to a 10 degree (17 per cent) incline and warns against significantly rough terrain, loose dirt, sand or gravel, standing water, ice and extreme slopes. Hills and distance are what it is for. Trails, beaches and deep gravel are not.

Caregivers and family

The SmartDrive changes the dynamics of caregiver-user pairs in ways worth noting.

Reduced reliance on push assistance. Family members and caregivers who previously assisted with pushing on outings often shift to a different role: walking companion rather than pushing partner. The relational dynamics around outings change.

Caregiver learning. Anyone who may need to help should sit in on the dealer training rather than being taught second-hand, and should know in particular how to switch the power assist off. Permobil is explicit that the wearable is worn only by you; it is not passed to a helper.

Transport. Permobil supplies a foam stand to stop the SmartDrive moving and being damaged in a car, and advises that in a taxi you ask the driver to hand you the unit rather than let it go loose in the trunk. For flying, Permobil issues a SmartDrive Airline Passenger and IATA certificate, and states that arrangements must be made with the airline operator and approval received before the departure date. Whether the unit comes off the chair at all depends on your vehicle and your transfer, and that is the question most worth rehearsing at the dealership with your own car rather than settling in the driveway afterwards. Four of the six people in the Swedish study could lift it in and out of a car; two could not.

Category 6: interabled use cases

For couples and households where one person uses a wheelchair and the other does not, the SmartDrive changes what a walk together looks like. Participants in the Swedish study described going further, planning less, and stopping avoiding slopes. A partner who had been doing the pushing on outings becomes a companion on them instead, which is a different relationship on a Sunday afternoon.

Who it tends to suit

What follows is general orientation, not a clinical recommendation and not advice about your own situation. Permobil requires an assessment and documented training with a dealer, and your occupational therapist or physiotherapist is the person who decides whether this device fits you, your chair and your funding route.

Manual wheelchair users managing shoulder load. This is the main reason the device gets prescribed, and it was the primary reason in the Swedish study. Shoulder pain is the most common musculoskeletal pain syndrome among wheelchair users in the meta-analysis cited above, and longer duration of wheelchair use is one of its strongest determinants.

Spinal cord injury. This is the population the published SmartDrive research was done in. Clinical practice guidelines on upper limb preservation after spinal cord injury exist and are what your clinician will work from. We have not found a guideline that sets a specific year of injury at which power assist becomes recommended, so this review does not quote one; earlier write-ups that give a 10 to 15 year threshold do not cite a source for it.

Post-polio syndrome, multiple sclerosis, and other energy-limiting conditions. Reducing the number of pushes a day costs is the mechanism, and it is the same mechanism whatever the diagnosis. There is no SmartDrive-specific published evidence in these populations, so ask your clinician to reason from your own pushing load rather than from a category.

People who steer and brake on the handrims. The SmartDrive assumes you brake on the rims and, if you use the wearable, that you can tap a hand against the rim reliably. If either is uncertain, the wired SwitchControl or an external switch is the route to ask about rather than the reason to rule the device out.

Where it is a harder fit

Limited hand function. Do not let anyone rule this device out on hand function before the alternatives have been tried. The wired SwitchControl comes with every unit, takes about 0.9 lbs (4 N) of force to press, can be latched so it does not need holding, and accepts an external mono jack switch or a Buddy Button. Permobil’s training sheet also directs the dealer to try the MX2 and MX1 control modes and latched mode when the standard skills cannot be performed. Braking on the handrims is the requirement that does not have a workaround here.

Tremor and involuntary movement. Tap recognition may be unreliable, and Permobil warns separately that the wearable can be activated accidentally. The switch controls avoid the tap vocabulary altogether. This is a question for the assessment, with the actual device, not a category exclusion.

Users requiring full-time power chair function. The SmartDrive extends manual chair use; it does not replace a power chair for users whose conditions require full-time powered seating.

Judgement in the moment. Permobil’s training certification asks you to accept responsibility for knowing when the assist must be off, including on downhill slopes and at curbs. Whether that is workable is a matter for the assessing clinician and the person themselves, not for a review.

Rough ground. Permobil explicitly warns against significantly rough terrain, loose dirt, sand or gravel, standing water, icy surfaces and extreme slopes, and notes that these can cause a loss of traction. Trail riding, beaches and deep gravel are outside what the device is built for.

The manufacturer

Permobil is a Swedish manufacturer of wheelchairs, seating and power assist, selling in Canada through a dealer network. It acquired Max Mobility, and with it the SmartDrive, in 2017.

The recall, and what it says about the company. This is the substantive thing to know. Permobil has now recalled the SpeedControl Dial twice. The second action, which withdraws every Dial ever sold including the ones shipped as replacements under the first recall, followed the discovery that the design fault had been present since the Dial came to market in April 2022. Permobil states that the fault can produce “continued drive”, where the SmartDrive fails to stop when the Dial is pressed inward, and “involuntary movement”, where the motor activates with no user input while the Dial sits at zero. The company is not offering repairs, parts or replacement Dials; it tells users to cut the cord and destroy the part, and supplies a SwitchControl, or a SwitchControl with Buddy Button, free of charge. It has notified the US Food and Drug Administration. Read that two ways at once: a company that pulls a whole product line rather than patch it is behaving as it should, and a control component on a device people rely on to stop got through with a fault that took two recalls to close out.

Warranty. Two years against manufacturing defects, limited to repair or replacement of the defective part, and voidable by modification, by use outside the manual, or by damage in transit at the purchaser’s place of business. Permobil also states it is not responsible for damage to your wheelchair caused by attaching or operating the SmartDrive, which is worth knowing before the clamp goes onto a chair you paid for separately.

Pricing transparency. Permobil does not publish list pricing; dealers quote on configuration, and the funding route adds another layer. Ask for the quote itemized and compare where you can.

Research. Permobil maintains a public research library and published the summary of the independent Swedish study cited throughout this review, including the finding that only one of six participants could mount and dismount the unit unaided. A manufacturer that publishes the awkward finding alongside the flattering ones is doing something most do not.

Veterans. Canadian veterans should go through Veterans Affairs Canada’s Programs of Choice, where wheelchairs and power mobility devices sit under POC 13, Special Equipment, and require a prescription from a VAC approved health professional and pre-authorization.

Verdict

The SmartDrive MX2+ is the most widely fitted rear power assist in Canada, and for people whose shoulders are carrying the cost of every push, the case for some kind of assist is well supported. Range extension is real and specified. Fitting onto most manual chairs is workable.

What holds it back is not the motor. It is that a 14.4 lb assembly has to get on and off the chair, and the only long-term study says most people could not do that from the chair unaided; that a control component has been through two recalls; and that whether you can afford it depends entirely on which province you live in and whether somebody told you to get authorization before you bought.

Three questions to take to the assessment, in this order. Can you get it on and off your own chair, and into your own car, on a bad day rather than a good one? Which control are you being offered, and have you tried the wired SwitchControl as well as a wearable? And who is paying, what do they require, and does that requirement come before you buy? Get those three answered and the rest of the decision is straightforward.

Where to buy

• Motion, formerly Motion Specialties, with locations across Canada
• Regional Permobil-authorized dealers, through the Permobil Canada dealer locator
• Veterans Affairs Canada, POC 13 Special Equipment, for eligible veterans
• Your provincial assistive devices program, which sets its own rules and usually requires authorization before purchase

Always get a clinician-led assessment before purchase, and confirm your funding program’s rules in writing first. Permobil requires documented dealer training with a signed skills certification, so treat the fitting appointment as part of the purchase rather than an extra.

Frequently asked questions

Sources

• Permobil, SmartDrive MX2+ User’s Manual (specifications, controls, charging, omni-wheel and roller maintenance, inspection list, warranty, training certification).
• Permobil, SmartDrive MX2+ product page (Canada).
• Max Mobility / Permobil, SpeedControl Dial Voluntary Field Action (recall scope, failure modes, replacement, disposal instruction, Canadian contact, 2017 acquisition).
• Permobil, SmartDrive Smartwatch Compatibility Guide.
• Permobil Clinical Research, summary of Butler Forslund E, Lofvenmark I, “Effects of the SmartDrive on mobility, activity, and shoulder pain among manual wheelchair users with spinal cord injury: a prospective long-term cohort pilot study”, Disability and Rehabilitation: Assistive Technology, 2022. Six participants, Sweden, six months.
• Liampas A et al., “Musculoskeletal Pain Due to Wheelchair Use: A Systematic Review and Meta-Analysis”, Pain and Therapy 2021;10(2):973-984, doi:10.1007/s40122-021-00294-5.
• Mobility Management, “Permobil Acquires MAX Mobility”, 3 January 2018.
• Veterans Affairs Canada, Treatment Benefits: Programs of Choice.
• Motion and the Permobil Canada dealer locator.

Related reading

• Brand spotlights on the Canadian and European manufacturers whose chairs the SmartDrive attaches to.
• Our adaptive equipment repair and maintenance coverage, for the long-term ownership picture.
• Our wheelchair selection guides, for chair compatibility.

The SmartDrive is the most widely fitted but not the only power assist. It is a rear-mounted device; pushrim-activated wheels and front-mounted units work differently and suit different chairs and different bodies. Ask your clinician to compare at least one of each type before you settle, and to say why they are recommending the one they are recommending.