They are the two most popular modifications in the automotive world, a set of new rims for your car and a big muffler for your motorcycle. The manufacturers aren’t silly, they’ve long since cottoned on to the trend, offering factory mags for just about any car and the option for an Akrapovic exhaust for even a learner-legal motorcycle. But while both are popular in the car world, few on two wheels truly change their rolling stock, other than those who simply go for the absurd. When it came to his 2022 Triumph Bobber, however, one man was desperate for a well sorted wide tyre ride. So, Queensland’s Purpose Built Moto was picked for the build and they’ve covered all bases in turning the tame Triumph into a big-wheeled badass.

Starting with a new motorcycle has a lot of advantages for both customiser and the client, with no need to rebuild the broken or waste time chasing those little niggling issues. This leaves the full budget to be spent on the exact changes a client wants, and at PBM, Tom Gilroy has a sixth sense for tapping into those desires. “The brief for the project was simple, as Doug was a long-time fan of the shop and trusted our styling. He wanted a wide-wheel bobber, kept simple, custom paint and styled up with some trick Purpose Built Moto parts, and a hand-crafted exhaust. The rest was up to us.”

Tom is the first to recognise the work of the UK’s Thornton Hundred in making the big wheel look popular on the Bobber. Jody and his team build a beautiful bike, but they too follow in a long line of builders on both sides of the Atlantic who have pushed to the limits just how much rubber you can fit under any single machine. From the popular world of choppers with their common 300-section conversions to the team at Roaring Toyz who have built an empire out of fitting even bigger tyres under any number of modern sportbikes. The key, however, if you don’t want just the looks but are indeed after a bike that can truly be ridden hard, is to get the maths just right.

Doing the sums Tom selected a 160 x 17” for the front and a fat 180 x 17” for the rear and turned to Canyon Motorcycles in the US to come up with the goods. “Known for making custom wheels to fit about any Triumph or Harley Davidson these guys were the obvious choice. We got in touch and with luck on our side their first production run of wide triple clamps for the bobber had just been finished. We worked out our wheel sizing and before long we had all the parts needed to make it happen.” And the selection of Pirelli Angel GT tyres is spot on, they look great while offering excellent all-weather performance, with enough movement in the sidewall to still offer exceptional cornering.

Clearly, the factory fenders were no longer going to fit, but part of the joy of going with PBM is they can literally purpose-build any part you need. Tom started at the rear end and although the blank fender he started with looked like it should fit, it took considerable rolling, trimming and shaping to get it just right. But rather than opt for traditional strut mounts, a piece of 8mm steel plate has been used to create a stunning support that helps the fender float over the fat rubber. “The front fender needed to be made from scratch, so again I’ve hand-shaped the sheet metal to fit the tyre profile and fabricated up a clean, although slightly ornate front fender bracket to match the style of the rear.”

Having nailed the tin work, it was over to Nathan from Livin Loco Garage to talk paint, and Doug had requested a deep metallic green. With that in mind, Tom and Nathan put their heads together and the Livin Loco legend got creative, coming up with both a wicked colour and a simple but stunning graphics package. A green/teal candy is used as the primary colour, with matte black used as an accent and on the graphics, and silver chosen to tie the two together. Even the stock headlight and side covers get hit with the combo, and it results in a custom but classy appearance.

The big 1200cc parallel-twin just might be the perfect engine for a bobber, the aesthetic has always made sense, just look at old Triumphs or the Yamaha XS650. But what really makes this engine that much better is the 270º crank, which helps to deliver more torque, less vibration and the kind of lumpy sound you get from a 90° V-Twin, which has the same firing order. To up the ponies and spit the perfect tune, fabricator Dylan worked on a 2 into 2 design that takes advantage of the old cat cavity. The pipes step up to 2” out of the ports and then flow to meet each other on the same side, with internal mufflers along the way and beautiful outturned ends.

To finish out the build, there were a few loose ends to tie up, and rather than ruin the beautiful metal work of the fender by screwing in a number plate, a better solution was devised, with a swingarm-mounted unit the end choice. “Using our tail tidy kit, a set of Omni 3-in-1 lights and some chromoly tube it was a fun part of the fabrication making these functional pieces of the motorcycle look good,” Tom tells us.

The finished result is a true hot rod for the high street, tough yet understated, and with a big set of boots. Doug is quite obviously over the moon and Purpose Built Moto add another feather to their cap, as they conquer the challenge of building a wide-wheeled weapon, that retains excellent riding dynamics.

[ Purpose Built Moto | Photography by Nine Fivers ]