So far, we’ve taken a pretty close look at how Guru Cycles designs their custom bikes and preps the carbon frames in Part 1 and how those frames come together in Part 2. Now, we get to show you the other side of their business with the steel and titanium frames. Then the finishing and painting process that gets them ready to ship.
Shown above is a titanium frame in their digital alignment table. The spring-loaded “pokers” holding up the seat tube are wired into the system and show how far they’re extended compared to the clamp holding the bottom bracket shell. They can be moved to check any part of the frame, letting the welder confirm alignment after tacking and welding.
But how does it get to this point? Put on those safety goggles and come on in…
UPDATED: Guru’s response regarding ti welds added to bottom of post.
As we learned at Interbike, Guru’s been streamlining their lineup to make things a bit more efficient. They only really make steel and titanium bikes now. They used to do aluminum and will still build one or two track bikes a year, but that’s about it.
For titanium, it’s all U.S. sourced 3/2.5 material with tube diameters from 12mm chainstays up to 44.5mm for the downtubes. They use diameter rather than butting to doctor the stiffness of the frame. They say this gives the desired result without adding the additional weight and complexity of butting.
The bends are all done in house.
The bottom bracket shells and headtubes are all made in house. This gives them a lot more flexibility to create custom frame sizes since off-the-shelf parts (head tubes in particular) only come in limited sizes. It also lets them control the stiffness of the headtube by controlling the diameter by subjecting it to more or less lathing. Lastly, it lets them mix and match headset styles, using an integrated upper cup and external lower cup to add a bit of headtube length without the visual weirdness of a massively tall tube.
The other benefit is that they end up with thicker tubes than what’s available elsewhere. They found that thinner 3rd party BB and HT parts would deform too much during welding, which could result in poor headset and bottom bracket performance. Guru’s tube ID’s (interior diameters) are left intentionally too tight throughout the welding process, then they’re machined after everything’s welded to the correct measurements for a precise fit.
They make their own dropouts in house, and the design is brilliant. Both stay contact points are rounded with a constant radius. So, once the seat- and chainstays are mitered, they make full contact at any point on the curve, so Guru has a range of angles to work with from just a single part.
Once the tubes are selected for a particular frame, they go to the middle of the shop floor for cutting and mitering. Then, like the carbon tubes, they’re binned with all parts for a frame in a bucket with geometry chart and instructions.
Then they head to the welding room, run by Michel Jacques, a former pro downhill racer, and Luc Moreau, both came from Balfa. They worked together there and were recruited by Guru when Balfa was purchased by Rocky Mountain and moved out of Montreal.
We’ve seen welding before, but it’s always a treat to watch it in action. Welding tubes with wall thicknesses is tricky, because you need to make sure the bead adequately penetrates each without destroying the thinner one or not fully melding with the thicker one. It’s an art, and they seem to be quite good at it.
Here, the dropouts are tacked in place…
…and then fully welded. All of the heat coloration will be polished off, but dang does it look neat.
Once the frames are all put together, they’re queued up for sanding, painting and finishing.
Different stages of sanding are done before any paint or coating is applied and then again between coats as necessary to get the desired result.
Like any good custom builder, paint schemes run from mild to as wild as you’re willing to pay for. It’s not just the decals they were printing in Part 1, it’s masks to get detailed art and logo work on the frames.
Frames are racked to dry a bit between coats.
Once all the paint’s done, a protective clear coat goes on. This is the buildup on one of the stands. Pretty, no?
Once the clear coat is applied, they’re put on a spinning rack to dry. The frames rotate slowly while drying to prevent any runs or light/heavy spots.
When it’s all dry, they’ll get a final inspection then they’re wrapped up and boxed. Complete bikes get partially built first, but this is the end of the line before the delivery company makes someone a very happy cyclist.
Thanks a ton to Jodi and the rest of the Guru team for showing us around!
GURU’S RESPONSE RE: TITANIUM WELDS
From Tony Giannascoli, Founder: Please allow us to chime in on the posts regarding Guru’s welds. Guru has been welding titanium frames for more than 10 years already and we take great pride in our craftsmanship and in our weld quality. We were pleased when Tyler accepted our invitation and we allowed him to snap pictures of anything he wanted as we are transparent and have nothing to hide.
Weld zone discoloration is inevitable when welding outside of an inert chamber. In the bicycle industry, since weld bead aesthetics are important, frames are welded outside of an inert chamber but steps are taken to ensure the integrity of welds. Firstly, the interior of the frame is purged of all oxygen using Argon gas. Then, a specially designed cup which diffuses Argon gas evenly is used to purge any oxygen from the outer surface of the weld. Inevitably, some discoloration will be evident with this technique. It is only a few microns thick and can be easily removed using scotch brite to finish the surface (photo above).
Note that we’ve had our welds tested by independent laboratories using x-rays and micrographs. In all cases, the results demonstrated very low levels of porosity and high levels of purity with virtually no contamination. The ultimate test for our welds is fatigue and impact testing which we regularly conduct at Guru. These tests demonstrate that when frames are brought to the point of rupture due to excessive abuse, the welds never break. Furthermore, we have many clients who have been riding their Guru-made titanium frames for well over 10 years without any incidents (Editor’s note: They added via phone that their titanium models are by far their most durable frames, virtually without any warranty issues). This is the true testament to the quality of our titanium frame construction.