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Thomson Dirt Drop gravel handlebar review

The American brand has just expanded its curly bar range with the flared, gravel-specific Dirt Drop

Thomson Dirt Drop gravel handlebar review
(Image: © Guy Kesteven)

Bike Perfect Verdict

Extra flared, large-diameter bar that’s great for boosting stiffness and steering leverage. It’s very expensive though and small paw riders will struggle

Pros

  • +

    Conventional top shape

  • +

    Super-wide, control-boosting flare

  • +

    Stiff and precise

  • +

    No vibration buzz

  • +

    Great for big hands

Cons

  • -

    Expensive

  • -

    Not for small hands

  • -

    Unforgiving in the rough

  • -

    You’ll need to recalibrate your taping

Thomson is better known for the bits that hold bars but this distinctive dirt drop bar is great if you like a fatter, stiffer and extra-flared feel on the front end of your gravel machine. You’re paying a premium for the name though and they aren't the best gravel handlebars for small hands. 

Thomson Dirt Drop gravel handlebar with no tap fitted

Unlike most other bars, the 31.8mm clamp area extends to the drop sections (Image credit: Guy Kesteven)

Design

In terms of dimensions, the Dirt Drop uses a classic compact 130mm drop, 90mm throw shape in three widths which top out at the 460mm span we tested. However, the flare is a really pronounced 25-degree angle that pushes the lower part of the bar out to a properly wide 570mm at the tips. It also rotates the shifter hoods slightly, too, though not as dramatically as some bars. You get a single laser-etched mark for aligning the bars with a rotational Plimsoll line in the center for squaring things up with the stem. The other notable feature besides the big flare is the fact that Thomson has extended the 31.8mm central diameter all the way out to the bends.

Thomson Dirt Drop gravel handlebar detail of 31.8mm top section

When wrapped, the tops have a lot of thickness (Image credit: Guy Kesteven)

Performance

The effect of the diameter becomes obvious as soon as you start taping as while most bars shrink down not far from the stem creating an obvious start point for wrapping, the Thomson's stay fat all the way across. That means a lot of volume - even if you’re using a thin tape but if you’re wrapping with 3mm thick like we did it’ll look like you’ve double wrapped Roubaix racer style. The extra bar diameter means you might have to use less overlap than normal just to make sure you have enough left to finish the full bar.

That fat girth obviously effects the feel of the bar in your hands and, while some of our testers really liked having plenty of bar in their hands, riders with smaller paws really struggled and started to cramp on longer rides. That’s compounded by the fact that while the Thomson wasn’t as bruising as we thought it might be on rougher, harder surfaces, it’s certainly not soft and forgiving. Thin-wall design thankfully means it doesn’t buzz and numb your hands over smaller bumps/gravel surfaces and as we say some of our testers felt the fat dimensions helped them relax rather than death gripping the bar. The pronounced flare gives a really wide descending position in the drops, too, significantly increasing stability and confidence when the trails got challenging. 

The precise feedback from the bar also helps when surfing the stick or slide line of limited grip steering on gravel or greasy mud and gives you a really stiff base to wrestle big gears round from. The oversized build does make it relatively heavy though and it’s definitely expensive for an alloy bar.

Thomson Dirt Drop gravel handlebar detail of clamping area while fitted to a bike

Marks on the handlebar help center and align the bar and stem (Image credit: Guy Kesteven)

Verdict

Thomson’s Dirt Drop is very expensive and the extended big girth design makes it unforgiving for smaller hands and/or on rough terrain. If you’ve got big hands, aggressive pedaling and steering tendencies or just like a solid cockpit to play with, it feels super precise and flex-free and the big flare adds serious power steering leverage for lairy moments.  

Tech Specs: Thomson Dirt Drop gravel handlebar

  • Price: $134.95 / £115.00
  • Weight: 298 grams (46cm, claimed)
  • Width: 420, 440 and 460mm
  • Sizes: 31.8mm only

Guy Kesteven is Bike Perfect and Cyclingnews’ contributing tech editor. Hatched in Yorkshire he's been hardened by riding round it in all weathers since he was a kid. He spent a few years working in bike shops and warehouses before starting writing and testing for bike mags in 1996. Since then he’s written several million words about several thousand test bikes and a ridiculous amount of riding gear. To make sure he rarely sleeps and to fund his custom tandem habit, he’s also penned a handful of bike-related books and talks to a GoPro for YouTube, too.


Rides: Pace RC295, Cotic FlareMax, Specialized Chisel, Vielo V+1 gravel bike, Nicolai FS Enduro, Landescape custom gravel tandem

Height: 180cm

Weight: 69kg