Custom Tumbleweed Prospector for off-road world touring

My first bike was a £170 second hand road bike. The geometry was ancient and it had mechanical issues, but it got me interested in cycling. My second bike was a gravel bike. I was still figuring out my particular cycling interests (terrain, etc.), but I still think it was the right choice at the time as it gave me the flexibility to explore different terrains and with wider tyres and a better granny gear, a broad range of terrains opened up to me. I still felt an urge to take trails the bike couldn’t handle, ones you want a mountain bike for.

My first big tour across South Africa was done, and with a desire to tour around Africa and the rest of the world developing, I realised my bike knowledge was good enough to look for my third bike: one that would take me around the world. I started asking around to get ideas before my SA trip had even begun, so I had the whole trip to sit on the idea and use it to figure out what I enjoyed. I was close to going for a Surly, but eventually settled on the Tumbleweed Prospector. Amongst a whole host of reasons, in summary It’s designed as an expedition MTB for the Rohloff hub.

I figured I know enough about bikes now, and wanted to extend my knowledge further. I ended up modifying so many parts on my gravel bike, I didn’t want to waste the stock components on this one. So I decided to purchase the frameset and select the components I wanted. The priorities I came up with after researching the experiences of others were that the parts had to be as reliable as possible, minimise maintenance, maximise comfort, while only then really factoring in weight and cost. I’m not going to even mention the final cost. Suffice to say it’s not cheap, but if you were to buy a 4x4 for a world tour I can assure you it would cost 10-100 times more. Selecting components When I upgraded the tyres on my gravel bike to 2” wide, rough terrain was significantly easier. Problem is they left minimal clearance, and mud would cause real issues. With the Prospector, I was told I could comfortably fit up to 27.5x3.0” tyres, so I went with Surly Knards in this size. I long considered going 26” for the availability of spares in developing countries, but there weren’t nearly as many wide tyre options in this size. At least I know the Prospector can fit 26” tyres and can replace the whole wheel if it comes to that.

Having chosen to go with a Rohloff hub, I read of the importance of good wheel build. People have damaged their Rohloff hubs by riding on broken spokes. So I searched for an experienced wheel builder, which wasn’t hard to find living near London. I went with SBS Cycles. I took their recommendation for hub and spokes. I’m having them setup as tubeless, with a SON28 dynamo hub up front. I’m going with 32 spokes for the wheel strength, and would have gone for 36 but that’s what Rohloff and Son offer. The frameset comes with a 180mm rear disc brake, and I picked a similar one from Shimano for the front. I hadn’t realised this before, but larger rotors mean more braking power. I chose Avid BB7 callipers, as I was told they were one of the best. I considered rim brakes for a long while, and I still think they are a good choice for long distance touring; but sadly the Prospector isn’t designed to take them.

Tyres	27.5x3.0 Surly Knard
Rims	DCR Full Volume Rims
Front hub	Son28 Dynamo Hub
Rear hub	Rohloff 14-Speed Hub
Front rotor	Shimano Deore 180mm 6-bolt
Rear rotor	Rohloff 180mm 4-bolt
Callipers	Avid Mechanical BB7 MTB Brake Calliper
Spokes	Sapim Race Spokes Black
Valves	Milkit

I considered, and still might change my mind before the big trip, going with a belt drive. It is the ultimate in terms of maintenance, not needing to be lubed, and belts last longer than chains. However, Daniel at Tumbleweed suggested against it and gave me a very good reason: replacement parts aren’t nearly as widely available. So it’s a chain for now at least.

To complete the drivetrain, Daniel recommended a super boost crankset to give a good chainline for the Rohloff hub. So I went with the Shimano Deore M6130. You’ll notice I chose Shimano Deore parts where possible, because I learned that Shimano parts are more readily available throughout the world and I chose to standardise on the Deore groupset for its good price point. I opted for a KMC e1 chain, which was designed for hubs like the Rohloff. I’m used to using SPD pedals, and I like having a flat side, so I’m trying Shimano PD-T8000 XT pedals.

Crankset	Shimano Deore M6130
Chain	KMC e1
Pedals	Shimano PD-T8000 XT MTB SPD Trekking Pedals

Saddles are perhaps one of the most personal parts of a bike, in that everyone’s butt is different. I’m glad I had a bike fitter experienced in saddles who suggested the Fizik Antares R3. He did so with little thought and hesitation, and used a saddle pressure mat to validate his suggestion. Along with an Endura chamois, I seldom feel any pain after hours and hours in the saddle. When I do, it’s usually because I didn’t wash the chamois well enough. After much research between aluminium and carbon seatposts, I learned that aluminium is the better choice for touring. It’s sturdier under load and the load dampens the ride about as much as a carbon seatpost. I’m happy I came across the Thomson Elite, as it appears to be virtually indestructible, which is what you want on a long tour.

Seat post	Thomson Elite Setback Seatpost
Saddle	Fizik Antares R3 Open

Handlebars are another very personal choice. My gravel bike has standard drop bars, which while great for their speed, didn’t work for me when going off-road. I also lost most of the hand positions from loading gear up front, and ended up using the hoods on top 90% of the time. I’m trying out the Jones H-Bar on the Prospector, which seems like a sensible choice given the Prospector was designed for flat bars with some amount of sweep. I’ve added in Ergon GC3 grips, as I’ve heard many people recommend them on the Jones bar. I followed my theme of Shimano Deore parts for the brake levers, while the Rohloff comes with its own rotational gear shifter.

Handlebars	Jones H-Bar Butted Loop Aluminium
Grips	Ergon GC3
Stem	Lixada MTB Bicycle Handlebar Stem (placeholder until I get the new bike fitted)
Brake levers	Shimano Deore Bl-M6100

I am reusing the super bright kLite front light from my gravel bike, which I’ve received complaints of being too bright from pedestrians. I am getting a Garmin Varia for the rear, which doubles as both a rear light and infrared car scanner to alert me of cars behind me. And I’m reusing my Garmin Edge 520 Plus, which has served me well barring a few annoyances.

Front light	kLite Bikepacker ULTRA V2 - XT30 - Gravel / Road
Rear light	Garmin Varia RTL515
Navigation	Garmin Edge 520 Plus

After trying a stock Ortlieb frame bag on my gravel bike, I quickly realised the benefit of a custom frame bag which fit the frame exactly. I had nearly designed and built my own, before realising it wasn’t worth the effort when someone more experienced could do the job a lot better and more efficiently. I worked with Straight Cut in Scotland, primarily for being nearby. I’m working with them again for the Prospector. Out front, I have been using rubber straps to tie my sleeping gear to the handlebars. Sometimes this leads to the bag rubbing against the front tyre though, so for the Prospector I’m adding in a T-rack from Tumbleweed, which also allows me to mount extra bottle cages or dry bags on the sides. This should enable me to carry more gear up front. On the rear, I’m fed up with using a saddle bag (they’re too small, and sag when over-packed), and decided to move to panniers. I have ordered the Mini Pannier Rack from Tumbleweed for use with Ortlieb’s highly-rated Roller Classic Panniers. I look forward to the extra spare capacity these changes provide, while knowing I need to be careful not to over-pack!

Frame bag	Straight Cut custom frame bag
Front rack	Tumbleweed T-Rack
Rear rack	Tumbleweed Mini Pannier Rack
Rear panniers	Ortlieb Roller Classic Panniers
Bottle cages	Lezyne Power Bottle Cage

I considered long and hard about going with front suspension. Ultimately I’ve decided not to, largely due to reliability. A rigid front fork als enables me to carry more gear up front if the need arises, although I kind of hope not.