Thor·Class B·2025

Thor Sequence 20A

Name: Thor Sequence 20A
Brand: Thor
Price: 105000 USD

4across 1,400 reviews on retail listings

|21 ft|9,200 lbs|Sleeps 2

The Thor Sequence 20A is a straightforward, no-nonsense Class B on the Ram ProMaster. One of the most affordable ways to get into a factory-built Class B.

Budget Class BFirst-TimersCouples

MSRP from

$105,000

$$$ Premium

ChassisRam ProMaster 3500

Engine3.6L V6 Gas

Solar100W

Slide-Outs0

Specifications

Length

21 ft

Weight

9,200 lbs

Sleeps

Fresh Water

20 gal

Gray Water

12 gal

Black Water

8 gal

Features

Murphy Bed

Wet Bath

2-Burner Stove

Swivel Cab Seats

Backup Camera

Power Awning

Highlights

One of the cheapest factory Class Bs you can buy

Murphy bed layout maximizes daytime living space

Simple build means less to break and easier maintenance

What owners report

Summarized from Reddit and owner forums — not a first-hand test.

The Thor Sequence 20A is the affordable on-ramp to Class B van life. Built on the Ram ProMaster with the gas Pentastar V6, it gives you a compact, drive-anywhere van for around $105K — tens of thousands less than a Mercedes Sprinter equivalent — and skips the diesel DEF system and pricey dealer-only service that come with a Sprinter. The front-wheel-drive ProMaster's low, flat floor also makes the interior feel more open than a comparably sized Sprinter.

The trade-off is Thor's quality control, which owners on classbforum.com and thorforums.com flag repeatedly. Plumbing leaks and electrical gremlins are described as known issues — one owner chased a self-starting generator to control wires that had worn through against the axle. Cabinet and cooktop rattles are routine (felt pads are the standard fix), and the tall ProMaster body catches crosswinds enough that adding SUMO springs front and rear is a widely recommended ~$500 upgrade. Tanks are small, and the wet bath is space-efficient but divisive.

The Sequence 20A is for couples who want the freedom and parkability of a Class B without the Sprinter price of entry, and who don't mind sorting out a few first-year bugs. Against the Mercedes-based Thor Delano 24FB it gives up the diesel's range, AWD, and refinement but saves you roughly $70K. Against a Winnebago Solis (also ProMaster-based) it's competitive on price with similar quirks. Buy it for value and the gas drivetrain, budget for suspension and rattle fixes, and keep an eye on the wiring and plumbing early on.

What owners like

+At around $105K it's tens of thousands cheaper than a comparable Mercedes Sprinter Class B like the Thor Delano
+Gas engine means cheaper, more widely available service than a Mercedes diesel
+Wet bath, galley, and convertible sleeping in a footprint you can take almost anywhere
+Active owner communities on classbforum.com and thorforums.com share fixes for nearly every quirk
+Easy aftermarket suspension upgrades (SUMO springs front and rear) dramatically improve the ride for about $500

Common complaints

−Thor's quality control draws consistent criticism — owners describe plumbing leaks and electrical gremlins as known issues
−One owner traced a generator that kept self-starting to control wires that had rubbed through against the axle
−ProMaster is front-wheel-drive only, so it's not a true off-pavement rig like an AWD Sprinter
−The ProMaster's tall, boxy body catches crosswinds, and owners recommend suspension upgrades for stable highway driving
−Small fresh and gray tanks limit boondocking duration for two people
−Wet bath means the toilet, sink, and shower share one space and everything gets wet

Questions owners ask

Is the Thor Sequence 20A four-wheel-drive or AWD?

No. It's built on the front-wheel-drive Ram ProMaster, so it's a road-and-light-gravel van, not an off-pavement rig. If you want to handle snow, mud, and rough forest roads, you'd need an AWD Sprinter-based van like the Thor Delano or an Airstream Interstate instead.

Gas ProMaster or diesel Sprinter — which is better?

The ProMaster's gas Pentastar V6 is cheaper to buy and service, has no DEF system to deal with, and the flat floor feels roomier. The Sprinter diesel gets better fuel economy and range and offers AWD, but costs much more upfront and ties you to Mercedes service. For budget-conscious road touring the ProMaster wins; for long-haul and off-grid the Sprinter does.

How reliable is the Thor Sequence 20A?

The ProMaster chassis is solid, but Thor's house-side quality control is the weak point. Owners report plumbing leaks, electrical issues, and rattles, plus a notable case of generator control wiring that wore through against the axle. None of it is usually catastrophic, but expect a shakedown period and a thorough inspection of wiring and plumbing.

Does the Sequence 20A need suspension upgrades?

Many owners say yes. The tall, boxy ProMaster catches crosswinds and can feel unsettled at highway speed. Adding SUMO springs front and rear for around $500 is the most commonly recommended fix and owners report it makes a world of difference in stability through turns and gusts.

How long can two people boondock in it?

A night or two comfortably. The small fresh and gray tanks are the limiting factor more than power. With careful water use you can stretch it, but the Sequence is better suited to campgrounds and short off-grid stays than extended boondocking without refills.