Best Electric Bike Conversion Kits 2027

The best electric bike conversion kit 2027 shoppers can fit without a workshop is the Swytch Max+, a front-hub kit with a handlebar battery that BikeRadar fitted in about 25 minutes and scored 4 out of 5. If you want more hill power and don't mind a harder install, a mid-drive kit such as the Bafang BBSHD or the TongSheng TSDZ2 is what the testers recommend. If you want no wheel swap at all, the Skarper DiskDrive clips onto a disc brake bike, but at £1,495 it costs about as much as a complete budget e-bike. The honest catch: conversion kits are rarely cheaper than a new e-bike once you add the battery, a decent donor bike and the install, and a kit is only worth it if you love the bike you already own.

That is the main finding of this guide, and the tests back it. T3 said the Swytch Kit Pro's price was too high for its modest motor and battery, and that better-value complete e-bikes are the more sensible choice for most buyers. Wikipedia makes the same point, noting that the cost of conversion kits isn't much lower than the cost of complete bikes. I compare the kits that testers have actually fitted, explain which types suit which bikes, and cover two things most guides skip: US power limits and the 2026 federal proposal that names conversion kits.

I haven't fitted or ridden any of these kits. Everything comes from BikeRadar, Cycling Weekly, Cyclingnews, Popular Science, T3, Electric Bike Report, Electric Bike Review, Wikipedia and the Federal Register, and I label each number as tested, listed or claimed. Most of the hands-on tests are UK ones, so prices are in pounds where the tester gave pounds. Checked October 9, 2026.

This page may contain affiliate links, which means ElectricMood can earn a commission if you buy through them. See the affiliate disclosure. For complete bikes at any price, see my best electric bikes guide.

Best electric bike conversion kits 2027 at a glance#

Prices are as the named source listed them, in the currency it used, and they differ by country and date.

My rule: pick the kit type first (below), then the brand. Most buyers should choose between a Swytch-style hub kit for simplicity and a mid-drive for hills.

How I chose these kits and what the testers did#

Conversion kits are harder to compare than complete bikes, because the result depends on the bike you fit them to. These are the sources I leaned on and how they test:

• BikeRadar (guide published September 7, 2026) fitted and rode the Boost, Skarper DiskDrive and Swytch Max+ and reported range, setup and handling. A separate BikeRadar review of the Swytch Max+ (November 30, 2025) timed the install and measured range on two bikes.
• Cycling Weekly (published 2022, updated August 19, 2026) tested six kits, from the Swytch Air to the Bafang mid and front hub kits, and gives a "how to choose" guide.
• Cyclingnews (updated January 19, 2026) fitted each kit to a bike, timed the install, and tested range, ease of use and durability.
• Popular Science (February 2024) picked kits partly from hands-on use and partly from buyer reviews, and says so for some entries.
• T3, Electric Bike Report and Electric Bike Review supplied older Swytch and Rubbee tests that I use as context, not as current specs.

To be in my main list, a kit needed at least one tester who had fitted it, a company that still exists, and a clear fit story: what bikes it works with and what you need to check. I left out kits I could not find a hands-on test for. I cannot compare range numbers across testers, because bikes, riders and routes differ, so I show them separately.

Swytch Max+: best easy conversion kit#

What it is. A front-hub kit: you swap your front wheel for one with a 250 W motor and clip a battery to the handlebar. BikeRadar lists a 250 W front hub with up to 40 Nm of torque, a 272 Wh battery with a claimed range of up to 40 miles, and USB-C output so the battery can charge a phone. It adds about 3.6 kg.

What the tests found.

• Install: BikeRadar's reviewer took about 25 minutes on a 20 inch folding bike and longer on a 700c single-speed, mainly to line up the disc brake and rotor, because the Swytch hub is spaced wider than the original wheel.
• Range: 20.54 miles on the folding bike and 28.7 miles on the 700c single-speed. BikeRadar expects more on a geared bike. Both are well below the 40-mile claim.
• Ride: Five assist levels and five speed-limit presets. Front-wheel drive "takes getting used to": on steep climbs the rider needs weight forward to avoid front-wheel slip, especially when wet.
• Verdict: 4 out of 5. The reviewer said he would still choose the Skarper for simplicity, but called the Swytch easy to fit, with fast charging and good value.

What fits. Wheel sizes 700c, 26 in, 650b/27.5 in and 16 or 20 in for folding bikes. The handlebar mount has three positions and fits drop and riser bars, but a narrower bar needed a £10 display arm. Cycling Weekly's earlier test of the Air and Max says the system needs a 10 mm dropout width, so older frames may need modification.

Prices and models. BikeRadar lists £999 for the Max+ as tested, £759 for the standard Max and £1,250 for the Max++. The older Air was $1,199 and the Max $1,599 in Cycling Weekly's 2022 review, and T3 priced the earlier Kit Pro at $1,499. I could not confirm current US prices, so check the maker's page.

What it costs you. T3's earlier test found the assistance weak and fading above about 14 mph, and called the price too high for the motor and battery. BikeRadar's guide notes the conversion is one-way: you buy a wheel built to your bike. Cyclingnews lists the Swytch's range as short, with a claimed 20 km for the small pack.

Check the current price

Skarper DiskDrive: best conversion kit with no wheel swap#

What it is. A compact drive unit that clips onto a special disc rotor on the rear wheel. Cycling Weekly's test lists 45 Nm; Cyclingnews and Popular Science list 250 W and a 240 Wh battery, and BikeRadar gives the drive unit's weight as 3.9 kg. Cyclingnews says motor and battery together weigh about 4.5 kg.

What the tests found.

• Install: Simple to fit and easy to remove. BikeRadar says it can turn a regular bike into an e-bike "in seconds" once the rotor is fitted, and Cyclingnews notes professional installation is included.
• Ride: Smooth power. BikeRadar praises a feature called Dynamic Climb that raises assistance on steeper hills, and says range beat expectations: 71.5 km on gravel and 90 km on road.
• Cons: BikeRadar notes no remote control, a hard-to-see battery light and a high price. Cycling Weekly adds that durability is unproven and Eco mode could be stronger.

What fits. Disc brake bikes only. Cycling Weekly calls it the best for compatibility with any disc-brake bike.

Price. £1,495 at BikeRadar and $2,005 on a Ribble listing quoted by Cycling Weekly and Cyclingnews. Popular Science calls it "eye-popping" and the "best splurge." Cycling Weekly says it is cheaper than a rear-hub Mahle e-bike but considerably more expensive than most kits.

My view: it is the most elegant kit on this list and the hardest to justify on price. It suits someone with a disc brake road or gravel bike who wants to switch between electric and normal riding.

Check the current price

Bafang BBSHD and TongSheng TSDZ2: best mid-drive conversion kits#

Mid-drive kits replace your crank with a motor in the middle of the bike. Popular Science and Cycling Weekly agree that they give the best performance and the most torque, and that they are harder to install and usually cost more than hub kits.

Bafang BBSHD#

Popular Science names the Bafang BBSHD its best overall kit, with a 750 W motor, a throttle and a large battery of 48 V (the text says just under 1,000 Wh). Its stated con is price. I could not find a price in that article, and the Bafang pages I saw were seller listings, so I don't quote one. Cycling Weekly's Bafang mid motor kit is listed at 80 Nm, fits 68 to 73 mm bottom brackets, keeps your existing wheels and is "capable off-road." Its cons are limited ground clearance for big obstacles and no battery in the box. Cyclingnews says the instructions could be more detailed.

Check the current price

TongSheng TSDZ2#

Cycling Weekly names the TongSheng TSDZ2 its best mid-drive: lightweight for its power, compatible with a wide range of bikes and with better ground clearance than a Bafang. Cyclingnews describes a 500 W motor with a torque sensor and 80 Nm peak, and a natural feel, but weak installation guidance. Cycling Weekly's range estimates are about 29 km with a 10 Ah battery and about 53 km with an 18 Ah battery. The battery is sold separately, and the crank and chainrings have to come off. Cyclingnews lists it at $331.48.

Check the current price

What to check before buying a mid-drive#

• Bottom bracket width. The Bafang kit fits 68 to 73 mm shells per both Cycling Weekly and Cyclingnews. Check yours.
• Frame material. Cycling Weekly says the Bafang kit is compatible with alloy frames.
• Drivetrain wear. BikeRadar warns that drivetrain parts may wear or break under extra load, so budget for chains and cassettes.
• Battery. None of these include one. Cycling Weekly suggests a reputable brand and a 36 V battery as a safe choice.

Hub motor kits: budget front and rear wheel conversions#

A hub kit replaces a wheel with one that has a motor built in. Popular Science says front kits are easier to install and cheaper, while rear kits perform and balance better.

Bafang front hub kit#

Cycling Weekly calls it the best budget front hub: 65 Nm, a choice of batteries (11.6 to 17.5 Ah, or none), about 28 to 42 miles of range, and compatibility only with disc brakes and quick-release axles in 20 to 28 inch wheels. Prices shown were $285.13 and $663.09 on AliExpress listings. Cyclingnews tested a version with an 840 Wh battery, found it powerful and high quality, but said installation is time-consuming and cable management is hard.

Check the current price

Voilamart 48V rear wheel kit#

The cheapest kit in Cycling Weekly's list: a 45 Nm rear hub for under $300 (about £250). Pros: inexpensive, plenty of power, clear display. Cons: some parts feel cheap, no battery in the box, the crank has to come off to fit the pedal sensor, and it is not waterproof. The reviewer recommends adding waterproofing to the connectors.

Check the current price

A caution on very cheap kits#

Popular Science also lists a front-hub kit under $200 (Pexmor, 1,200 W) and a 1,000 W rear-hub kit as value picks, but does not say it tested them, and one pick (EBIKELING) was chosen from buyer reviews. I would treat those as unverified. The front-wheel "pulling" sensation that Popular Science notes is also what BikeRadar describes for the Swytch.

Other conversion kits worth knowing#

These appear in tests and guides, but I either could not find enough to rank them or they suit a narrower buyer.

The Rubbee case is a useful warning. A snap-on kit from a company that disappears leaves you with a battery you cannot replace and no support. Popular Science's list also includes a Rubbee X, so check whether a seller still stands behind the one you are looking at.

Which type of conversion kit is right for your bike#

Popular Science's guide describes the first three as hub, mid-hub and snap-on kits. Its notes on power are worth remembering: kits typically run 500 to 1,200 W against 250 to 750 W for typical complete e-bikes, because some power is lost in the conversion. That is a good reason not to read a kit's wattage as a mark of quality.

Wikipedia adds a point about the donor bike: not every bicycle is built to be strong enough to handle electric power. BikeRadar warns that heavy components fitted where the frame wasn't designed for them can affect handling. If your bike is a cheap, flexy or damaged frame, a kit will not fix it.

Will your bike take a conversion kit? A compatibility checklist#

Every tester repeats the same warning: check before you buy. This is the list I would work through.

1. Brakes. The Skarper needs a disc brake. The Bafang front hub needs disc brakes and a quick-release axle, per Cycling Weekly. T3 fitted the earlier Swytch Kit Pro to a rim-brake bike, while BikeRadar's Max+ tester used disc brakes and did not cover rim brakes, so ask Swytch about your brakes.
2. Dropout and axle width. Cycling Weekly's Swytch test says the system needs a 10 mm dropout width. T3's reviewer found the threaded axle fit only partway into two bikes' dropouts and needed force to seat, and an Electric Bike Report tester filed the axle shoulders to fit 9 mm dropouts in 2021. Either suggests measuring first.
3. Wheel size. Swytch covers 16 in to 700c per BikeRadar. The Bafang front hub covers 20 to 28 in.
4. Bottom bracket. Mid-drives need a standard shell: 68 to 73 mm for the Bafang kit.
5. Frame and fork. Electric Bike Review's tester of the Rubbee clip-on advised against using it with carbon seat posts, and a reader of one Swytch review reported a carbon fork was unsuitable. Treat carbon with caution and ask the maker.
6. Tyres and wet grip. BikeRadar notes narrow road tyres may wear faster and wet grip can be an issue with a drive wheel pushing on them.
7. Handlebar and cable space. Handlebar and downtube batteries need room. BikeRadar's tester needed a spare part for a narrower bar.

If any of these fail, the kit may need parts that raise the cost, or the bike may not be worth converting.

Is a conversion kit cheaper than a new e-bike?#

Usually no, and it depends on what you already own. The numbers that testers give:

Compare those with complete bikes. In my budget e-bike guide, the Lectric XP Lite 2 was $799 and the Lectric XP4 was $999 in the sources I used, with a battery, brakes, lights and warranty included. BikeRadar warns that repairs, a replacement donor bike or paying a shop to fit a kit can erase any saving, and that a kit only makes sense if the donor bike is in decent condition.

My view, based on those numbers:

• A kit makes sense when you already own a bike you love or one with special parts (a classic steel frame, a folding bike you travel with), you can do basic mechanical work, and you want a modest assist.
• A complete e-bike makes sense when you would otherwise buy a donor bike, need a warranty from one company, or want a strong motor, hydraulic brakes and a certified battery in one package.

For the cost of complete bikes in more detail, see my e-bike cost guide.

Power limits, classes and the law#

Kits are often sold by wattage, but the law cares about the final bike.

• United States. Wikipedia's summary of e-bike laws says US federal law defines a low-speed electric bicycle as one with working pedals, a motor under 750 W and a motor-only top speed under 20 mph (with a 170 lb rider). Many states use three classes: Class 1 pedal assist to 20 mph, Class 2 with a throttle to 20 mph and Class 3 pedal assist to 28 mph. That means a 1,000 W or 1,200 W kit, which is common in the lists above, may not meet the federal definition of an e-bike. State and local rules vary, so check yours.
• Labels. According to the same article, California requires the classification label to be replaced if a user changes the speed capability by modifying the bike, and Illinois and Massachusetts have similar rules. A kit that changes speed or power can trigger that.
• United Kingdom. BikeRadar says kits are legal in most places but in most of the UK the motor is limited to 250 W continuous and assistance must cut out above 25 km/h (15.5 mph); pedalling is required, and a throttle works only at low speed. Throttle-controlled kits can be classed as mopeds or electric motorcycles and must be taxed and insured. The minimum age is 14.

One conflict to know about: Cycling Weekly's guide says every kit in its list is legal in the US and UK/EU, while BikeRadar's UK rules would exclude some high-power and throttle kits. I would not accept a seller's "legal everywhere" claim without checking your own rules. For how classes work, see my guide to e-bike classes.

Battery safety and the 2026 CPSC proposal#

Conversion kits are where battery safety questions are sharpest, because the battery and charger often come from a different seller than the bike. In June 2026 the US Consumer Product Safety Commission published a proposed safety standard for lithium-ion batteries in micromobility products. Three things in it matter to kit buyers:

• Conversion kits are named. The notice says it covers "components sold in eBike electrical system conversion kits." An SGS summary quotes the proposal as requiring components marketed as part of a conversion kit to comply with specified sections of UL 2849-20.
• Replacement batteries are covered. User-replaceable battery packs sold separately would need to comply with UL 2271, and aftermarket chargers face their own requirements.
• It is a proposal, not a final rule. Public comments closed August 24, 2026. I did not find a confirmed compliance date, so I can't say when it would apply.

The notice describes 227 incidents from 2019 through 2023, with 39 deaths and 195 fires, and says 53% of the incidents occurred while the product was plugged in. It also gives an example of a consumer who bought a conversion kit that changes a standard bicycle into an e-bike.

What I'd do as a buyer: look for a UL 2271 or UL 2849 listing on the maker's own page for the battery and the system, not only in a marketplace listing. Cycling Weekly's advice for kits without a battery is to buy from a reputable brand and consider a 36 V pack. My own habit, not a rule from the notice: charge on a hard surface, away from exits and where you sleep, and unplug when full. I haven't verified the certification status of any kit above, so ask the seller.

How to install a conversion kit#

Install difficulty varies a lot, which is why the type matters.

• Front hub (Swytch-style). Cycling Weekly's steps: move the tyre and tube to the new wheel (with the hub cable on the non-drive side if the tyre is directional), clamp the handlebar bracket, attach a magnet disc to the left crank with a sensor in line with it, plug in the cables and tidy them. BikeRadar's tester took about 25 minutes on a folding bike; Cycling Weekly's reviewer took under 30 minutes including removing the old parts.
• Mid-drive. Remove the existing crank and chainrings and fit the supplied ones, according to Cycling Weekly. Popular Science says these need more toolbox know-how but rarely expert skills. Cyclingnews says the Bafang front hub kit's install was time-consuming and cable routing hard.
• Rear hub (Voilamart). Cycling Weekly's reviewer replaced the rear wheel, brake levers, display, throttle, control box and pedal sensor.
• Clip-on (Skarper). Quick once the special rotor is fitted; professional installation is included, per Cyclingnews.

If you are unsure, pay a bike shop. Expect that to add to the total cost, as BikeRadar warns. Keep your tyres at the right pressure afterwards, since a heavier, motorised bike is harder on them; my electric bike pumps guide covers pumps.

Which conversion kit should you buy?#

My picks by situation, based on the tests above.

For most readers I would not recommend the cheapest unbranded kit. Pick one the testers fitted, from a company that is still trading, with a battery you can verify.

Frequently asked questions#

What is the best electric bike conversion kit 2027?#

The Swytch Max+ is the best easy kit in recent tests: BikeRadar fitted it in about 25 minutes and scored it 4/5. For hills, a mid-drive such as the Bafang BBSHD or TongSheng TSDZ2 is recommended by testers.

Which are the best electric bike conversion kits 2027 for beginners?#

Start with a front-hub kit like the Swytch Max+ or a clip-on like the Skarper. Mid-drive kits need crank removal and more tools.

Are electric bike conversion kits worth it?#

Only in some cases. They rarely cost less than a complete e-bike once you add a battery, a good donor bike and installation. They make sense if you already own a bike you love.

How much does an e-bike conversion kit cost?#

Popular Science says $150 to $800 or more, Cycling Weekly says about £300 to £750 plus a battery, and premium kits like the Swytch Max+ and Skarper are £999 and £1,495.

How hard is it to install a conversion kit?#

Front-hub kits took BikeRadar about 25 minutes. Mid-drives need the crank removed, and some hub kits are time-consuming, per Cyclingnews.

How far can a converted bike go on a charge?#

BikeRadar measured 20.54 and 28.7 miles from the Swytch Max+ against a 40-mile claim, and 71.5 km on gravel and 90 km on road from the Skarper. Range depends on bike, battery, rider and route.

Is a conversion kit legal in the US?#

It depends on the final bike. Federal law defines a low-speed e-bike as under 750 W and 20 mph on motor power alone, and states add classes. Kits of 1,000 W or more may not qualify.

Can any bike be converted to electric?#

No. Check brakes, dropout width, wheel size, bottom bracket and frame strength. Wikipedia notes that not every bicycle is strong enough to handle electric power.

Are conversion kit batteries safe?#

A certified battery is safer. The CPSC's 2026 proposal would apply UL 2271 to replacement packs and UL 2849 sections to conversion kit components, but it is not yet final. Look for certification on the maker's page.

What is the best electric bike conversion kit for hills?#

A mid-drive. Popular Science and Cycling Weekly both say mid-drive kits give the most torque, and the Bafang and TongSheng kits are rated at about 80 Nm.

Which is better, a hub kit or a mid-drive kit?#

A hub kit is easier to fit and cheaper; a mid-drive climbs better and keeps your wheels but needs crank removal and adds drivetrain wear.

The bottom line#

If you want the best electric bike conversion kit 2027 testers can recommend for simple fitting, choose the Swytch Max+ and accept the front-wheel feel and short real-world range. If you ride hills, choose a mid-drive and be ready for a harder install and a separate battery. If you want a clip-on that comes off, the Skarper is the elegant option at a high price. Before any of them, work out whether a complete budget e-bike would cost less, because for most people it will.

Prices and models change, so check the current price and specs on the maker's page before you buy. Since I haven't fitted or ridden these kits, treat my picks as a well-sourced shortlist and read a hands-on review of the one you choose.

Written by Paul Gendry. Last checked October 9, 2026. This is general information, not professional advice. Specs, prices and rules change, so confirm them on the maker's page and with local authorities.