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FM336 vs FM326 vs FM316: Best Carbon Gravel Frames Compared
When it comes to building a high-performance gravel bike without breaking the bank, the carbon frames from Permeants Bikes have been making waves among riders worldwide. In this comprehensive guide, we’ll share a real-world FM336 build review, explore the versatile Journey Carbon Gravel Frame, and compare three of the brand’s most popular models — the FM336, FM326, and FM316 — so you can pick the perfect platform for your riding style.
FM336 Build Review: Pro-Level Gravel Bike for Half the Price
By a real rider – 2 months of honest experience
Let me start with the truth: I was skeptical. When I first stumbled upon the Permeants Bikes FM336 carbon gravel frame online, the price seemed almost too good to be true. How could a full carbon frame with internal storage, T47 bottom bracket, and UDH hanger cost less than a mid-range aluminum frame from a big brand? After two months of riding, building, and testing, I’m ready to share my honest experience — including the good, the bad, and everything in between.
The $1,000 Question: Is Cheap Carbon Safe?
Before I even ordered, I spent weeks researching. The cycling forums are full of horror stories about exploding carbon frames from unknown manufacturers. But I learned to distinguish between open-mould frames (legitimate unbranded products) and dangerous counterfeits (fake logos, zero quality control). Permeants Bikes has been manufacturing carbon frames since 2007, and they provide independent ISO 4210 test reports — that gave me confidence.
The FM336 arrived in a solid box with thick foam inserts. First impression: the paint was flawless (I chose a custom RAL 5005 blue, glossy finish), and the carbon layup looked clean with no visible voids or unevenness. The frame weight (size M) came in at 1180g — exactly as advertised.
Building the Dream Machine: Component Choices
I paired the FM336 with a mix of mid-range and budget parts to keep total cost under $3,000. Here’s what I used:
- Groupset: Shimano GRX 810 1x (mechanical) — reliable and gravel-tuned
- Wheels: Hunt 35 Carbon Gravel Disc — a solid value carbon wheelset
- Tires: Panaracer GravelKing SK 700x43c — tubeless setup
- Cockpit: Zipp Service Course 70 XPLR alloy bar + stem
- Saddle: Fizik Terra Argo X5
The build was straightforward. The T47 threaded bottom bracket (I chose the 86.5mm version) installed without creaking — a refreshing change from press-fit BBs I’ve struggled with before. The internal cable routing was easier than expected thanks to pre-installed guide tubes. The UDH hanger is a nice future-proof touch, especially if I ever upgrade to SRAM Transmission.
First Ride Impressions: Stiff, Responsive, Surprisingly Comfortable
I took the FM336 on a 60km mixed-terrain loop: 40% pavement, 50% smooth gravel, 10% chunky fire road. The bike climbed exceptionally well — the bottom bracket stiffness felt comparable to my friend’s $4000 carbon race bike. Out of the saddle sprinting on pavement, there’s no noticeable flex.
On gravel, the compliance is real. The seatstays and fork are tuned to absorb chatter without feeling mushy. With 43mm tires at 30 psi, I was able to stay seated over washboard sections that would have rattled my aluminum bike. The geometry (head tube angle 71°, wheelbase 1030mm on size M) strikes a balance between stable descending and quick handling — not as twitchy as a pure road bike, but faster-feeling than many “adventure” gravel frames.
One surprise: the 0.8L downtube storage hatch is watertight and easy to open. I store a multi-tool, CO2 inflator, tire levers, a spare tube, and a snack — all secure with no rattling.
The Honest Downsides
- No instruction manual: You need some mechanical knowledge to build. The frame came with no assembly guide, though customer support answered my questions within 24 hours.
- Paint durability: After two months, there are a couple small chips from gravel spray. Fine for a rider’s bike, but if you want a showroom finish, consider extra clear coat protection.
- Brand recognition: At group rides, people ask “What brand is that?” — not a downside for me, but if you want instant status, stick with a mainstream brand.
FM336 Final Verdict
Buy it if: You’re a value-conscious rider who enjoys building your own bike. You want modern standards (T47, UDH, internal storage) without paying $4000+. You prioritize performance over logos.
Skip it if: You want a complete bike ready to ride out of the box. You need a shop for every repair. You prefer the reassurance of a local bike shop warranty.
Journey Carbon Gravel Frame: A Versatile Platform for Every Rider
When it comes to biking on diverse terrains, a gravel bike is an adventurer’s best friend. The Journey Carbon Gravel Frame from Permeants Bikes is a standout choice for those who crave versatility and performance. Designed for the rugged paths less traveled, this carbon gravel bike frame is engineered to deliver strength, lightweight agility, and a smooth ride. Let’s explore the features, benefits, and reasons why it might just be your next biking companion.
A gravel bike frame is the backbone of a bike designed for riding on mixed terrain, from paved roads to dirt paths and rocky trails. Unlike traditional road bikes, gravel bikes are built to handle the unpredictability of off-road conditions. The geometry of a gravel frame typically offers a more relaxed riding position, which enhances comfort on long rides. Additionally, these frames often accommodate wider tires, offering better grip and stability.
Lightweight and Durable Construction
One of the most remarkable features of the Journey Carbon Gravel Frame is its material. Made from high-quality carbon fiber, this frame offers an impressive strength-to-weight ratio. Carbon fiber is known for being incredibly strong yet lightweight, making it ideal for a gravel bike frame that needs to withstand rough conditions without weighing you down.
Versatile Design for Any Terrain
The Journey Carbon Gravel Frame is engineered for versatility. Whether you’re embarking on a long-distance tour or a quick ride through forest trails, this frame adapts effortlessly. It features a geometry that balances comfort and performance, ensuring a smooth ride regardless of the terrain.
Enhanced Stability and Control
Stability is key when navigating uneven surfaces, and the Journey Carbon Gravel Frame delivers. Its design allows for wider tires, which provide better traction and control. The frame’s geometry also contributes to a stable ride, allowing you to maintain confidence even on the most challenging paths.
Comfortable Riding Position
Long rides demand comfort, and this is where the Journey Carbon Gravel Frame shines. The relaxed geometry ensures that riders enjoy a more upright position, reducing strain on the back and shoulders. This design not only enhances comfort but also reduces fatigue, allowing you to ride longer and farther.
Why Choose Carbon for Your Gravel Frame?
Carbon gravel bike frames are renowned for their performance benefits. The material’s ability to absorb vibrations translates to a smoother ride, especially on rough terrain. This means less fatigue and more enjoyment on your adventures. Durability is another critical factor — carbon fiber excels in this regard. The Journey Carbon Gravel Frame is designed to withstand the rigors of off-road biking, ensuring longevity and reliability. Its resistance to corrosion and the elements makes it a trustworthy companion in all weather conditions. And let’s not forget the visual appeal: the sleek, modern look of carbon fiber adds a touch of sophistication to your bike.
FM336 vs FM326 vs FM316: Which Gravel Frame Is Right for You?
Permeants Bikes offers several carbon gravel frames, but the three most popular are the FM336, FM326, and FM316. Each has a distinct personality, optimized for different riding styles and terrain. In this section, we’ll compare them head-to-head so you can decide which one belongs in your garage.
Quick Overview: What Each Model Is Best For
| Model | Best For | Key Feature | Rider Type |
|---|---|---|---|
| FM336 | Mixed terrain racing, fast gravel | 0.8L internal storage, progressive geometry | Speed-oriented, race-ready |
| FM326 | Expedition bikepacking, long-distance touring | 1.2L internal storage, multiple mounting points | Adventure rider, gear hauler |
| FM316 | All-day gravel, endurance, weekend overnights | 0.8L storage, aerodynamic design | Versatile, comfort-focused |
Detailed Spec Comparison
| Spec | FM336 | FM326 | FM316 |
|---|---|---|---|
| Frame Weight (size M, painted) | ~1180g | ~1180g | ~1150g |
| Tire Clearance (700c) | 47mm (user-reported up to 50mm) | 50mm | 50mm |
| Internal Storage Volume | 0.8L | 1.2L | 0.8L |
| Mounting Points | 6 (incl. top tube, under downtube) | 8 (adds fork cage mounts) | 6 |
| Head Tube Angle (size M) | 71.0° | 71.5° | 71.0° |
| Wheelbase | 1030mm | 1040mm | 1030mm |
| Chainstay Length | 425mm | 430mm | 425mm |
| Bottom Bracket | T47 threaded | T47 threaded | T47 threaded |
| UDH Hanger | Yes | Yes | Yes |
| Best Use | Racing, mixed terrain, fast group rides | Multi-day bikepacking, heavy loads | Endurance, light bikepacking, all-road |
FM336: The Racer’s Choice
The FM336 is designed for riders who prioritize speed, stiffness, and race-ready handling. Its progressive geometry (71° head angle, 1030mm wheelbase, 425mm chainstays) strikes a balance between stable high-speed descending and quick accelerations. The 0.8L internal storage is just enough for a race-day toolkit, and the frame weight under 1200g keeps the bike lively on climbs. If you’re planning to race gravel or enjoy spirited group rides, the FM336 is your weapon.
Ideal for: Gravel racers, fast mixed-terrain riders, those who want a lightweight platform without sacrificing modern features.
FM326: The Expedition Workhorse
The FM326 is built for adventure. Its 1.2L internal storage is the largest in the lineup, capable of swallowing a full tool kit, rain jacket, and snacks. Eight mounting points (including triple-pack mounts on the fork legs) let you strap on cargo cages, extra water bottles, or anything else you need for multi-day trips. The slightly longer wheelbase (1040mm) and slacker head angle (71.5°) add stability when the bike is loaded. If you plan to live off your bike for a week, the FM326 is the obvious choice.
Ideal for: Bikepackers, self-supported tourers, riders who carry a lot of gear.
FM316: The All-Day Endurance Option
The FM316 splits the difference between the FM336 and FM326. It shares the same 0.8L storage as the FM336 but adds an aerodynamic profile that makes it faster on pavement sections. The geometry is slightly more relaxed than the FM336 (identical numbers, but with aero shaping), making it comfortable for long days in the saddle without feeling sluggish. Tire clearance of 50mm gives you flexibility for rough routes, and the 1150g weight is the lightest of the three. The FM316 is the ideal “one bike for everything” — from weekday commutes to overnight adventures.
Ideal for: Endurance riders, mixed-surface commuters, weekend bikepackers who don’t need maximum cargo capacity.
How to Decide: A Simple Guide
- Do you race or prioritize speed? → FM336
- Do you go on multi-day self-supported trips with lots of gear? → FM326
- Do you want one bike for everything — fast enough, comfortable enough, with some storage? → FM316
There’s no wrong choice — each frame represents excellent value. Your decision should hinge on how you ride 80% of the time. If you’re still unsure, contact the Permeants Bikes team with your typical routes and gear needs, and they’ll help you pick the perfect match.
Frequently Asked Questions
Is a carbon gravel frame from Permeants Bikes safe and tested?
Yes — every Permeants Bikes frame is independently tested to 1.3× ISO 4210 standards. Third-party test reports are available on request. The company has been manufacturing carbon frames since 2007, and their quality control processes distinguish them from fly-by-night manufacturers selling untested open-mould products.
Can I upgrade the internal storage on the FM336 or FM316?
No — internal storage is built into the frame during manufacturing and cannot be retrofitted. If you need more than 0.8L of storage, the FM326 with its 1.2L compartment is the better choice.
Will the FM336 fit 50mm tires?
The FM336 is officially cleared for 47mm tires, but many users report that 700x50mm tires fit fine with proper rim width. If 50mm is a must for your riding, the FM326 or FM316 (both officially supporting 50mm) are safer bets.
Which Permeants Bikes gravel frame is easiest to build at home?
All three frames use T47 threaded bottom brackets and internal routing guides, so assembly difficulty is similar across the lineup. The FM326 has slightly more cable guides for dynamo lighting options, but all are DIY-friendly with basic mechanical skills.
What is the difference between the Journey Carbon Gravel Frame and the FM-series frames?
The Journey Carbon Gravel Frame is a versatile platform designed for a broad range of riders, from fitness enthusiasts to adventure seekers. The FM-series frames (FM336, FM326, FM316) are more specialized — the FM336 targets racers, the FM326 targets bikepackers, and the FM316 targets endurance/all-road riders. All share carbon construction and modern standards like T47 BB and UDH hanger.
Ready to Build Your Dream Gravel Bike?
Whether you’re drawn to the race-ready FM336, the adventure-hungry FM326, or the do-it-all FM316, Permeants Bikes has a carbon gravel frame that fits your riding style and budget. Every frame comes with ISO 4210 certification, modern standards like T47 threaded bottom brackets and UDH hangers, and the kind of build quality that big brands charge twice as much for.
Don’t just take our word for it — browse the full FM336 product page for detailed specs, sizing charts, and customer reviews. If you need help choosing between models, reach out to the Permeants Bikes team — they’ll match you with the perfect frame based on your terrain, riding style, and build goals.
Start your gravel adventure today — your perfect frame is waiting at Permeants Bikes.