A Multi-Bike Review of the Tumbleweed Big Dipper Drop Bars – John Watson | The Radavist | A group of individuals who share a love of cycling and the outdoors.

Wide bars are becoming more and more prolific in the drop-bar MTB, touring bike, and even gravel bike subgenres. A craze that began with the Crust and Ron’s Bikes Towel Rack bars has now become widespread in the industry, with multiple brands putting their spin on an ultra-wide offering. Among these is Tumbleweed, who have worked to design a model suited for the Stargazer touring bike (one of my favorites in that subcategory of drop-bar bikes). Fittingly dubbed the Big Dipper Bars ($115), I’ve been stealthily test-riding them on two recent review bikes. I have some thoughts on the Big Dippers and the appropriate application for wide drop handlebars in general. Let’s check it out below!

Shorthand

Eagle-eyed readers might have noticed two of my last review bikes had mysterious no-label handlebars. Thanks to Photoshop, I could showcase the Big Dipper bars, pre-embargo date, without giving away their maker’s identity. Now that the cat is out of the bag so let’s look at these bars’ specs…

Specs:

Material: Triple-butted, heat-treated 7000 series aluminum alloy, ISO 4210 tested for mountain bike use
Widths: 51 cm, 54 cm, 57 cm C-C at the hoods
Clamp Diameter: 31.8 mm
Backsweep: 5°
Flare: 20°
Drop: 109 mm
Reach: 50 mm (overall reach from center of clamping area to center of tube at front of forward sweep)
Finish: Bead blasted black finish, polished silver coming soon!
Average weight: 385 g
Price: $115

Before we dive deeper into the Big Dipper, I want to discuss why you should probably try wider bars on your bike and what it requires in terms of bike setup to do so.

Wider Bars Mean Less Extension, More Control

When it comes to off-road riding, the mountain bike scene abandoned narrow bars in the late 1990s. You can thank NORBA for that craze. Early MTB bars were old motorcycle bars, often measuring a whopping 840 mm wide. Magura, Inter-Am, and Tomaselli were just a few brands that had their moto offerings plugged onto the cockpit of early mountain bikes.

Later, Tom Ritchey made custom Bullmoose bars after these wide torque monster bars were literally snapping stems at the quill insertion. Tom’s bars would be around 580 mm in width and that felt like a sustainable fit for these early MTBs. Above you can see one common handlebar spec (Inter-Am) in 1979 and 1980 compared to the later 1983 Ritchey Bullmoose.

Then came NORBA, the National Off-Road Bicycle Association, and with it, racing! Downhill and cross-country racing took the nation by storm. Suddenly, the bikes became less “exploration-oriented” and more race-focused. Angles got steeper, top tubes became compact, stems longer, and bars narrowed. The idea was “narrow=fast!”

My Starling Mumur has 840mm wide bars…

In the late 90s and early 2000s, mountain bike bars started to widen in the smaller circles of freeride and DH-focused riders. Their terrain had fewer tight and twisty trails, so a wider bar meant more control at higher speeds, and hitting trees wasn’t really a concern. Eventually, we got to where we are today, with 800 mm bars being the norm, with smaller groups riding wider bars and a majority of riders trimming their bars to fit them accordingly. Even a 700 mm bar is worlds away from a 450 mm bar of the 1990s.

Wide bars and short stems give these slack head angle mountain bikes more control as your hands are further behind the front hub (steering axis) of the bike. The further behind, the longer your leverage. Think of a pry bar as an example. The further away from the boulder you’re trying to move with a longer pry bar, the more leverage it has and thus, the less energy required to move the boulder. This isn’t an exact comparison, but it paints the picture in rough, broad strokes.

Why a Wide Drop Bar?

In the same way a wide MTB bar increases control and leverage, a wider drop bar can alter the control of specific bikes. If your drop-bar bike has a slack head angle and a long reach, with a short stem (70 mm and shorter), then chances are you need wider bars. If you’re a road racer or track racer, 42-46 cm bars are the norm, but if you’re on a touring bike, a drop-bar MTB, or a gravel bike with a slack front end, there are zero reasons you should be riding the same width bar as a crit racer.

However, this noted, riders with narrower shoulders might not feel the benefit of switching to as wide of bars as a broader shoulder rider would. I have a 46″ chest and my shoulders are 51″ wide in circumference. So, a 25.5″ wide (65 cm) drop bar feels appropriate for me. Meanwhile, a rider with a 40″ wide shoulder circumference might feel more comfortable on a 20″ wide drop bar (50 cm).

There is no reason a size XL gravel/drop-bar MTB/touring bike should come specced with a 46 cm wide bar.

The Big Scoop on the Big Dipper

Now that we’ve discussed the how and why of wide drop bars, we can get into the meat and potatoes of this review. The Big Dipper comes in three widths: 51, 54, and 57 cm. This is measured center-to-center at the hoods (where your hands will be most likely). Then, there’s a 20º flare, resulting in 66 cm center-to-center at the ends of the drops on the size 57 cm I have.

So, while climbing, pedaling across flat terrain, and any other time you’d be on the hoods, the Big Dipper (if sized correctly) is close to your shoulder width. When descending and you switch to the drops, you gain extra width for control. This is increasingly important as you add weight (load) to your bike. Especially if you’re putting your weight high on the handlebars as opposed to a setup with low-rider panniers.

When the front end of your bike takes a hit, and you’re low, and in the wide drops, you’ve got more control over what the bike is doing. Versus, on a 46 cm bar, the horizontal axis of your bars rotation is more acute, meaning every input will be more noticeable. Again, leverage. Wider bars = more leverage.

Applications

As I stated before, if your gravel bike has a slack front end and longer reach numbers with a shorter ( 70 mm and under) stem, you will probably benefit from wider bars. If you want a handlebar bag or bikepacking handlebar roll between your hoods, you probably want wider bars. If you ride a lot of singletrack or rough double-track roads… again. WIDE BARS.

Yet, not all bikes will benefit from these. Gravel bikes with steeper head angles might get kind of squirrely if you put a 70 mm stem and wide bars on. Mostly due to the fact that your hands will be closer to the steering axis–say the front hub for simplicity’s sake–meaning your leverage will be lower than if you brought your hands back considerably. These steeper front-center gravel bikes typically don’t have longer reach numbers either, so you might have some issues getting the “feel” or fit right. Some people size up to achieve a longer reach number, in order to ride a shorter stem and wider bars on these sorts of bikes.

On the Singular Gryphon, the Big Dipper bars made it all the more enjoyable. Not only the width at the hoods and drops but also the bend of the bars themselves. They offer lots of hand positions–are super comfortable thanks to the gentle backsweep–and the shallow drop of 109 mm meant it was easier to switch from the hoods to the drops on the fly.

With the Stigmata, these bars completely changed the way the bike rode. Why on earth a bike specced with a suspension fork, a slack front end, and a 70 mm stem on a size XL came with 46 cm bars is beyond me. I almost didn’t want to review it after my first few rides. The bike’s potential wasn’t unlocked until the Big Dipper bars made their way onto the front of the bike! Product designers, please take note: stop putting narrow-ass bars on rowdy-ass bikes!

A few things to mention: wide bars usually require new brake/shifter lines, and not all bar tape will wrap them. But why go with other bar tape options when Camp And Go Slow makes the best bar tape?

TL;DR and the Wrap-Up

As with all Tumbleweed Bicycles’ components, the brand’s objective with the Big Dipper was to design the best product for its use case. Tumbleweed makes adventure touring bikes. Its Stargazer remains one of the best in class production drop-bar touring bikes on the planet. As such, the brand needed to make a bar worthy of its build spec.

The Big Dipper bar is wide compared to most drop bars and in the same realm as other wide drop bars, like the Crust Towel Rack or Curve Walmer bar. It is ergonomic, reasonably lightweight, and much stronger than a typical drop bar (ISO 4210 fatigue and strength tested for mountain bike use).

By combining a subtle backsweep, a nice, wide flare, a shallow drop, and shorter reach, the Big Dipper bar has planted itself firmly at the top of the list for wide drop bars. If your bike has a slack front end, long reach numbers, and a short stem, you should give it a try! Use my method of measuring your shoulder circumference or width and size accordingly and for stem, a good general rule (used by PNW Components) is for every 20mm wider your drop bar is, your stem should be 10mm shorter. That should offer a good baseline to get started into your foray of wider drop bars.