Price: £599.99 | Motor: 2.0 HP peak (brushless) | Max Speed: 9 mph (14.5 km/h) | Incline: 12-level automatic (0–7°) | Deck: ~120 × 44 cm | Max User Weight: 120 kg | Folding: Yes (flat-fold, requires tools)
The Slim Interactive Auto Incline is the most capable compact treadmill in JLL’s Sunny range and the only one that can genuinely do the 12-3-30 workout. It combines a 12-level powered incline with a brushless motor, 9 mph top speed, and a flat-folding design, a feature set that none of its cheaper brand siblings can match.
At £599.99, it is also the most expensive compact treadmill JLL sells. Essentially, it’s the incline-equipped version of the JLL Slim Interactive without incline, priced at £499.99. Like all of JLL’s current treadmill range, this is a Sunny Health & Fitness product distributed exclusively in the UK by JLL Fitness from Birmingham. Your warranty and after-sales support go through JLL’s UK operation.
Quick Navigation
Who Is the Auto Incline For?
This treadmill suits people who want three things simultaneously: powered incline, a quiet brushless motor, and a compact machine that folds flat for storage. If all three of those matter, not two, but all three, the Auto Incline is the only machine in JLL’s lineup that delivers the combination.
Specifically, it suits two groups. First, the 12-3-30 crowd. This is the only compact treadmill in JLL’s Sunny range where you can actually do the 12-3-30 workout (12% incline at 3 mph for 30 minutes). Seven degrees of incline translates to approximately 12.3% gradient, which meets the threshold. The Helius Lite has no incline. The JLL Pegasus has 3-level manual incline that falls well short. The non-incline Slim Interactive has nothing. If you want a JLL treadmill, the 12-3-30 is your primary workout, and you need a compact machine, this is your only option under £600.
Second, flat-dwellers who want incline walking workouts but cannot accommodate an upright-folding treadmill. The Auto Incline folds flat to approximately 21 cm — not as thin as the Pegasus at 15 cm, but still slim enough to store under some beds or against a wall. If your living situation demands a machine that disappears after sessions and you want powered incline, the Auto Incline solves that problem.
It doesn’t suit hardcore runners. At 9 mph and with a ~120 cm deck, the same speed and deck limitations that applied to the non-incline Slim Interactive apply here.
And it doesn’t really suit people on a tight budget either. At £599.99, you are paying a £200 premium over the Helius Lite and a £100 premium over the Pegasus for a powered incline feature. The NordicTrack T Series 5, with an RRP of just £100 more and prices as low as £499 in sales, does all of this and more.
That said, it does have great user reviews, and the UK-based support is a genuine plus.
Specs at a Glance
| Specification | Slim Interactive Auto Incline |
|---|---|
| Model Number | SF-T722022 |
| Price | £599.99 |
| Motor | 2.0 HP peak (brushless DC) |
| Speed Range | 0.6–9 mph (1–14.5 km/h) |
| Incline | 12-level automatic (0–7 degrees / ~0–12%) |
| Running Deck | Approx. 120 × 44 cm (47 × 17.3 in) |
| Max User Weight | 120 kg (18.9 st) |
| Programs | 15 presets + 3 custom user profiles |
| Display | Adjustable LED — time, speed, distance, pulse, calories, incline |
| Connectivity | Bluetooth — SunnyFit App (free) |
| Quick Speed Buttons | 3 mph and 6 mph |
| Quick Incline Buttons | Level 3 and Level 6 |
| Assembled Dimensions | Approx. 152 × 78 × 137 cm (L × W × H) |
| Folded Dimensions | Approx. 146 × 81 × 21 cm (flat-fold) |
| Product Weight | Approx. 50 kg |
| Extras | Bottle holder, device holder, emergency stop clip, transport wheels |
| Warranty | 12+ months (JLL UK) |
The 12-Level Automatic Incline — A Feature That Justifies the Price?
The powered incline is what separates the Auto Incline from every other compact treadmill in JLL’s Sunny range. Twelve levels, adjustable from 0 to 7 degrees (approximately 0–12% gradient), controlled at the touch of a button mid-workout.
Quick incline buttons at levels 3 and 6 provide instant jumps to common training gradients. The incline motor adjusts smoothly and quietly. No jarring stops or loud mechanical grinding that cheaper incline systems sometimes produce.
What does 12% incline actually feel like? Walking at 3 mph on a 12% grade is substantially harder than walking at 3 mph on flat. Your heart rate climbs, your glutes and hamstrings engage in a way they simply do not on a flat belt, and your calorie burn increases by roughly 50–60% compared to flat walking at the same speed.
For people whose primary goal is burning calories during walking sessions, powered incline is the single most effective feature a treadmill can have. More impactful than higher top speed, more programs, or app connectivity.
The 12-3-30 workout, 12% incline, 3 mph, 30 minutes, works on this machine. Seven degrees gives you approximately 12.3% gradient, and 3 mph is well within the speed range. This is the only compact treadmill in JLL’s Sunny range where the 12-3-30 is possible. The Pegasus maxes out at roughly 5% with its 3-level manual incline. The Helius Lite and non-incline Slim Interactive have no incline at all. If the 12-3-30 is the specific workout that brought you to this page, the Auto Incline delivers it.
The incline also transforms the 15 preset programs. On the non-incline Slim Interactive, those programs can only vary speed — they create interval sessions between walking and jogging. On the Auto Incline, programs can vary both speed and incline simultaneously, creating hill walking workouts, rolling terrain simulations, and progressive incline sessions that are genuinely more varied and more effective than flat-only programs.
2.0 HP Brushless Motor
The Auto Incline steps up from the 1.25 HP peak motor in the non-incline Slim Interactive and Helius Lite to a 2.0 HP peak brushless motor. The additional power is necessary — driving a 12-level incline mechanism while maintaining belt speed requires more motor than a flat-only machine needs. The extra headroom also means the motor is under less strain during incline use, which should translate to better longevity and quieter operation under load.
The brushless design delivers the same noise advantages as the non-incline Slim Interactive and Helius Lite. At walking speeds, the motor is nearly inaudible. At jogging speeds with incline engaged, you will hear the incline motor adjust and your own footfall, but the drive motor itself remains impressively quiet. For flat and home office use, noise will not be a concern.
Speed tops out at 9 mph, matching the non-incline Slim Interactive. Quick-speed buttons at 3 mph and 6 mph are fewer than the non-incline model’s six quick-speed buttons (3, 4, 5, 6, 7, 8 mph), which is a curious cost-saving measure on the more expensive machine. You can still reach any speed using the increment controls, but the quick-jump convenience is reduced.
The Deck — Longer But Still Narrow
The running deck measures approximately 120 × 44 cm. Compared to the non-incline Slim Interactive at 120 × 42 cm, the Auto Incline gains roughly 2 cm of width, a marginal improvement. It remains substantially narrower than the Pegasus at 51 cm.
For incline walking, which is the machine’s primary use case, the deck dimensions are adequate. At 3 mph on a 12% incline, your stride is short and your foot placement is naturally centred. The 44 cm width is sufficient for this type of walking. At higher speeds or on flat, the same deck-length limitations that affect the non-incline Slim Interactive apply here: users over 5’8″ will feel confined at jogging speeds, and 9 mph on a 120 cm deck is uncomfortable for most adults.
The shock absorption deck provides basic joint protection. This matters more on an incline-capable machine because incline walking, particularly steep incline walking, places additional stress on ankles and knees compared to flat walking. The cushioning will not match the 16-point suspension system on the JLL T350, but it provides a noticeable improvement over walking on a hard surface.
Folding
The Auto Incline folds flat to approximately 21 cm. That is genuinely compact — thicker than the Pegasus (15 cm) or Helius Lite (~15 cm), but still slim enough to slide under many beds or store against a wall. Transport wheels allow the folded unit to be rolled into position.
But here’s the catch: folding requires tools. Unlike the Pegasus and Helius Lite, which fold and unfold with a simple mechanism, the Auto Incline requires you to unscrew the handlebar assembly each time you want to fold the machine flat.
This is not a 30-second operation. User feedback consistently flags this as the machine’s most frustrating design decision. One buyer noted they expected the handle to fold down easily and were surprised to find screws involved every time. Most users end up leaving the machine assembled rather than folding it daily.
This significantly weakens the flat-fold selling point. If you are buying this machine specifically because it folds flat and you plan to fold it after every session, test your patience threshold honestly. If you are realistic about leaving it assembled most of the time and folding it only when guests visit or you need the floor space, the folding mechanism works fine — it just is not a daily-use feature the way the Pegasus fold is.
At 50 kg assembled, the Auto Incline is the heaviest machine in JLL’s Sunny compact range (Helius Lite: 36 kg, Slim Interactive: 43 kg, Pegasus: 49 kg). The incline motor and reinforced frame add weight, which is expected. One person can move it on the transport wheels, but it is not a machine you will casually shift around the room.
SunnyFit App and Programs
Bluetooth connects the Auto Incline to the SunnyFit App, which is free with no subscription required. The app provides access to over 1,000 trainer-led workout videos, 10,000+ global routes, real-time metric tracking, community challenges, and personalised plans. This is the same free app available on every Sunny-branded treadmill in JLL’s range, and it remains genuinely good value.
The Auto Incline’s app integration is more valuable than on the flat-only machines because the incline data adds a meaningful dimension to session tracking. Monitoring your incline alongside speed, distance, and calories gives you a much clearer picture of workout intensity and progression over time. The app can also guide incline-based workouts through trainer-led sessions, which is more engaging than manually adjusting incline throughout a session.
Onboard, the 15 preset programs and 3 custom user profiles operate as they do on the non-incline Slim Interactive, but with the added dimension of incline variation. The adjustable LED display now includes incline level alongside time, speed, distance, pulse, and calories — essential information when running incline-based programs.
How Does It Compare?
| Feature | Auto Incline (£599.99) | Slim Interactive (£499.99) | JLL Pegasus (£499.99) | JLL T350 (~£589) |
|---|---|---|---|---|
| Motor | 2.0 HP peak (brushless) | 1.25 HP peak (brushless) | 1.25 HP / 2.5 HP peak (DC) | 2.5 HP / 4.5 HP peak (DC) |
| Max Speed | 9 mph | 9 mph | 7.5 mph | 11.2 mph |
| Incline | 12-level automatic | None | 3-level manual | 20-level powered |
| Deck Size | ~120 × 44 cm | 120 × 42 cm | 119 × 51 cm | 132 × 41 cm |
| Max User Weight | 120 kg | 120 kg | 120 kg | 120 kg |
| Programs | 15 + 3 custom profiles | 15 + 3 custom profiles | 15 + body fat test | 20 |
| Motor Type | Brushless | Brushless | Standard DC | Standard DC |
| App | SunnyFit (free) | SunnyFit (free) | SunnyFit (free) | None (Bluetooth audio only) |
| Fold Type | Flat-fold (~21 cm, requires tools) | Handlebar folds down | Flat-fold (15 cm) | Upright fold |
| Weight | ~50 kg | ~43 kg | ~49 kg | ~55 kg |
| Quick Speed | 3, 6 mph | 3, 4, 5, 6, 7, 8 mph | 4 preset speeds | 4, 8, 10 km/h |
| Warranty | 12+ months | 12+ months | 24 months P&L | 5-year motor / 2yr P&L |
| RunRank | 2.5/5 | 2.0/5 | 3.0/5 | N/A (full treadmill) |
Auto Incline vs non-incline Slim Interactive (£499.99): For £100 more, you get 12-level powered incline, a stronger 2.0 HP motor, and a marginally wider deck. You lose four quick-speed buttons (you only get 3 and 6 mph vs the non-incline’s six buttons).
If you want incline, the £100 premium is justified and essential — the non-incline model cannot replicate any incline workout. If you do not care about incline, save the £100.
Auto Incline vs JLL Pegasus (£499.99): The Auto Incline offers 12-level powered incline (vs 3-level manual), 9 mph top speed (vs 7.5 mph), and a brushless motor (vs standard DC). The Pegasus counters with a substantially wider 51 cm belt (vs 44 cm), simpler fold mechanism (no tools required), 15 cm flat-fold height (vs 21 cm), and a 24-month warranty (vs 12+ months).
For incline-focused walkers, especially the 12-3-30 crowd, the Auto Incline wins clearly. For comfort-focused walkers and general daily use, the Pegasus remains the better value.
Auto Incline vs NordicTrack T Series 5 (~£599–£699): The NordicTrack T Series 5 offers a 2.6 CHP motor (vs 2.0 HP peak), 10 mph top speed (vs 9 mph), a substantially larger 140 × 46 cm deck (vs ~120 × 44 cm), 21 levels of incline up to 10% (vs 12 levels up to ~12%), KeyFlex cushioned deck, Bluetooth speakers, and — if registered within 28 days — a lifetime frame, 10-year motor, and 2-year parts and labour warranty (vs 12+ months). It also includes a year of iFIT with 10,000+ trainer-led workouts that automatically control speed and incline.
The Auto Incline counters with a brushless motor (quieter), flat-fold storage (the NordicTrack does not fold at all), a steeper maximum incline for the 12-3-30 workout, and a free app with no ongoing subscription. Keep in mind, iFIT costs roughly £39 per month after the first year. If you have permanent floor space for a non-folding treadmill, the T Series 5 is a superior machine. The Auto Incline only wins if you need flat-fold storage or refuse to pay for iFIT, and it remains the better choice specifically for the 12-3-30 thanks to its steeper maximum gradient.
Auto Incline vs Reebok Jet 200 (~£799): The Jet 200 is a full-size folding treadmill that outclasses the Auto Incline in every performance dimension for roughly £200 more. It delivers a 2.25 HP motor, 11 mph top speed (vs 9 mph), a spacious 140 × 46 cm deck (vs ~120 × 44 cm), 15 levels of powered incline, 8-pod Air Motion cushioning (vs basic shock absorption), 31 onboard programs (vs 15), Kinomap compatibility, built-in speakers with USB charging, an adjustable cooling fan, and a lifetime frame, 10-year motor, and 2-year on-site parts and labour warranty (vs 12+ months). It folds upright with a soft-drop hydraulic mechanism, no tools required.
The Auto Incline counters with a lower price, a brushless motor (quieter), flat-fold storage (vs upright fold), a steeper maximum incline (~12% vs the Jet 200’s 15 levels which top out lower per level), and a free SunnyFit app (Kinomap requires a paid subscription). The £200 gap is the Auto Incline’s only real defence — if budget stretches to £799, the Jet 200 is categorically the better treadmill. The Auto Incline holds its ground only for buyers who need flat-fold storage, prioritise motor noise, or are locked to a £600 ceiling.
Build Quality and Design
The Auto Incline uses a steel frame reinforced to support the incline motor mechanism. At 50 kg, it is the heaviest Sunny compact treadmill in JLL’s range, and that weight contributes to stability during incline use. When the deck is raised to maximum incline, the machine remains planted without excessive vibration or lateral movement — important for safety when walking on steep gradients.
The incline motor itself operates smoothly. Transitions between incline levels are gradual rather than abrupt, and the motor noise during adjustment is minimal. Users have noted the smoothness of incline changes as a positive. The mechanical reliability of compact incline systems is always a question mark — moving parts in a budget-price machine — but Sunny’s brushless motor technology and the generally positive user feedback suggest the mechanism is well-engineered for its intended use.
The adjustable LED console displays incline level alongside the standard metrics, which is essential for incline-based training. The device holder accommodates phones and tablets, and the bottle holder keeps hydration accessible. The emergency stop clip provides standard safety protection.
Assembly is slightly more involved than the flat-only Sunny machines due to the incline mechanism, but remains manageable in 30–45 minutes with one person. Lubricate the belt before first use. The user manual is clear on maintenance requirements — Sunny recommends lubrication every 150–200 miles of use.
Warranty
JLL offers a minimum 12 months warranty on all fitness equipment. The Auto Incline, as the most expensive compact treadmill in JLL’s Sunny range, still receives the same minimum warranty as the cheapest. This is the product’s most conspicuous weakness. At £599.99, you are paying more than the JLL T350, which comes with a 5-year motor warranty and 2-year parts and labour. The Reebok Jet 100z at a comparable price offers lifetime frame and 10-year motor coverage.
The incline motor adds a mechanical component that flat-only machines do not have — a component that can fail. Having the shortest warranty in the comparison set on the machine with the most moving parts is not reassuring. JLL’s Birmingham-based customer service remains a positive, but the formal warranty terms are a legitimate concern at this price point.
Final Verdict — 3.5 RunRank
The Slim Interactive Auto Incline earns a 3.5 RunRank, half a point above the non-incline model and half a point below the Pegasus, because it solves a genuine problem for a specific audience. If you need powered incline, a quiet brushless motor, and flat-fold storage in a single machine, this is the only option in JLL’s lineup. That combination has real value for people in flats, small homes, and home offices who want effective incline walking workouts without a permanent treadmill footprint.
The 12-level automatic incline is the headline feature and it works well. Incline changes are smooth, the mechanism is quiet, and 7 degrees of gradient delivers genuine training intensity. The 12-3-30 workout — the specific routine that will bring many buyers to this page — works correctly on this machine. The SunnyFit app is free and adds meaningful guided content. The brushless motor keeps noise to a minimum.
The tool-required folding mechanism weakens the value proposition. If you buy this machine partly because it folds flat, you need to honestly assess whether you will unscrew and reassemble the handlebars regularly. Most users do not. If the folding is aspirational rather than practical, you are paying £599.99 for a compact treadmill that stays assembled, and at that point, the NordicTrack T Series 5 is unarguably the better purchase.
Buy the Auto Incline if you specifically need powered incline in a flat-folding form factor and the brushless motor’s noise advantage matters for your living situation. For the 12-3-30 devotee in a small flat, this is the right machine. For everyone else, the Reebok treadmill range may offer something more suitable, or even the JLL Pegasus at £100 less offers a better daily walking experience with a wider belt and simpler fold.
Frequently Asked Questions
Can you do the 12-3-30 workout on the Auto Incline?
Yes. This is the only compact treadmill in JLL’s Sunny range that supports the 12-3-30 workout. Seven degrees of incline translates to approximately 12.3% gradient, meeting the workout’s requirements. Set incline to level 12, speed to 3 mph, and walk for 30 minutes. The flat-folding design also makes it the most compact 12-3-30-capable machine in JLL’s full lineup.
What is the difference between the Auto Incline and the non-incline Slim Interactive?
The Auto Incline (SF-T722022, £599.99) adds 12-level powered incline and a stronger 2.0 HP peak motor. The non-incline model (SF-T722021, £499.99) has the same 9 mph speed, same belt width, and same brushless motor type but at 1.25 HP with no incline capability. The Auto Incline costs £100 more. If you want incline training, the premium is essential. If you do not need incline, save the money.
How does the Auto Incline compare to the JLL T350?
The T350 (~£589) has 20 incline levels (vs 12), 11.2 mph top speed (vs 9 mph), a longer 132 cm deck (vs ~120 cm), 16-point cushioning (vs basic), and a 5-year motor warranty (vs 12+ months). The Auto Incline counters with a brushless motor (quieter), flat-fold storage (vs upright), and free SunnyFit app (vs audio-only Bluetooth). If you can accommodate an upright-folding treadmill, the T350 is the better buy. The Auto Incline only wins on flat-fold storage and motor noise.
Does the Auto Incline fold flat?
Yes, but with a significant caveat. Folding requires unscrewing the handlebar assembly with tools each time. It is not a quick one-step fold like the Pegasus or Helius Lite. Most users report leaving the machine assembled rather than folding it daily. When folded flat, the profile is approximately 21 cm — thicker than the Pegasus (15 cm) but still slim enough to store against a wall or under some beds.
Is the Auto Incline quiet?
Yes. The 2.0 HP brushless motor operates very quietly at all speeds. The incline motor produces some sound when adjusting levels, but transitions are smooth and not disruptive. At walking speeds, the machine is nearly silent. Users have specifically praised the smoothness and quietness of incline changes.
Does the Auto Incline connect to Zwift or Kinomap?
No. The Auto Incline connects exclusively to the free SunnyFit app via Bluetooth. It does not support Zwift, Kinomap, or other third-party fitness platforms. For third-party app compatibility with incline, look at the Reebok Jet 100z (Zwift and Kinomap compatible) or Reebok FR30z.
What is the maximum incline in percent?
The maximum incline is 7 degrees, which translates to approximately 12.3% gradient. This is sufficient for the 12-3-30 workout (which requires 12% incline) and provides meaningful hill simulation for walking and light jogging. For context, the JLL T350 offers 20 incline levels, and the Reebok Jet 100z offers 12 levels of powered incline on a full-size platform.
Is this the same as the Sunny SF-T722022?
Yes. JLL Fitness is the exclusive UK distributor for Sunny Health & Fitness products. The hardware is identical — the Auto Incline sold on JLL’s UK store is the Sunny SF-T722022 with JLL’s UK warranty handling. Do not confuse it with the SF-T722021, which is the non-incline Slim Interactive at £499.99.
HomeTreadmill.co.uk is reader-supported. When you buy through links on our site, we may earn an affiliate commission at no extra cost to you. This does not influence our reviews or recommendations — our RunRank scoring is based entirely on product testing and research.
