Factory Tour – Guru Cycles, Part 3: Titanium Frame Building, Painting and Finishing

Factory Tour – Guru Cycles, Part 3: Titanium Frame Building, Painting and Finishing (UPDATED)

posted by Tyler Benedict - December 14, 2013 - 6pm EST (from Bike Rumor)

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!

GuruCycles.com
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.

Factory Tour – Guru Cycles, Part 2: Building a Carbon Bicycle Frame

Factory Tour – Guru Cycles, Part 2: Building a Carbon Bicycle Frame

posted by Tyler Benedict - December 11, 201

 

In Part One of our Guru Cycles Factory Tour, we showed how the design of the bikes goes from customer order through to a pile of tubes ready for assembly. Mostly, anyway.
Here in Part 2 we’ll finish the process and show how everything comes together to form a complete frame. I’ve seen plenty of carbon fiber bicycle manufacturing in our 5+ years of Bikerumor’s existence. Each time I head to a factory, I wonder what could be new? What could the next builder possibly do that’s different from all the rest. What’s amazing is that virtually everyone manages to surprise, and Guru’s no exception.
First, there’s the unique cut of the carbon swatches that make up the frame. It’s the most visible feature of their Photon bikes and gives it a slick sea snake appearance. Under all that carbon, though, is another very cool construction process I’d not seen before…


Guru’s engineers are constantly playing with different layups, seeing what improves the frame, what drops weight and, ideally, what will do both. Their bladder molding process leaves nothing inside except carbon, and this tube shows the patterned layups that help them achieve some incredibly light frames.

Most of the Photon’s tubes are made using a silicone bladder. The exception is the downtube/bottom bracket assembly. It’s put together with metal mandrels so they can create a single piece for better strength and stiffness while still getting the tolerances right for pressfit BBs.

Interior tabs between the BB shell and downtube add an additional point of contact for a stronger connection once it’s all heated and pressed, fusing the tubes together with a bit more structure. You know what it’s called when someone takes the time to add little touches like these? Love.

The layered BB shell wrap is folded over the top (click to enlarge and see the graduated layers), then more Love (carbon tabs) is applied over the sides.

The finished product looks like this.

Once all the tubes are molded, they’re binned with geometry charts and sent to the middle of the shop floor for mitering, then on to the tacking room:

This is where everything starts coming together in a recognizable form.

They also mold their own carbon dropouts, all with tooling made in house. What’s particularly cool about these is they allow for geometry adjustment without resorting to metal inserts. Simple solution to avoid mixed materials; better, lighter weight result.

With geometry sheets in hand, the jigs are set up to each bike’s specs.

The tubes are “tacked” into place with epoxy, bonding them together enough to hold their shape during the rest of the assembly process. Here’s where it starts to divert from most other builders.

With many carbon builders, the tubes start to get wrapped with the outer layers of carbon as soon as they’re positioned. Guru, however, is just getting started. First, they paint on a bonding agent leading up to each major joint.

That ensures the putty will stay stuck on the carbon during the sanding and shaping process. Wait, what? Putty?!?

Yep, all work and no play here at Bikerumor and Guru. Season’s Greetings!

Technically, it’s an epoxy molding compound, and it dries hard as a rock as its baked, which happens immediately after the frame is tacked together. That lets them easily sand and shape it.

Lest you worry about an expensive custom bike being weighed down by putty, it only adds about 6g to a finished bike.

Once it’s baked, this guy sands off most of it to create shapely tube junctions.


Looks good, but it’s not just for aesthetics…

Back in the clean room, the bikes are assembled using tube to tube construction. For the Photon series, that nonstructural putty adds functional shape to the headtube junctions. Since they’re only using UD fibers, the broader rounded shapes allow the fibers to be run over a bigger cross section without sharp bends.

Since UD fibers only do their job of stiffening the frames when in tension, this lets them spread forces across a larger area and put the strength in plane with how riding forces are actually acting on the frame. Olivier Lavigueur is the carbon wrapper and has been doing it here for more than five years, and has been at Guru for more than a decade.


After the overwrap is complete, a textile called Peel Ply is wrapped over it, then it’s vacuum bagged and put back in the oven to compress and mold the wrap to the frame. As with all carbon construction, the heat and pressure melts the resin between the fibers to effectively turn it into a single, solid piece.  Many of these techniques are borrowed from the aerospace industry, which is a huge part of the Montreal area’s livelihood.

Between tacking and wrapping, it gets checked for alignment, brake placement and tire clearance. Then it gets checked again when it comes out of the oven for the last time.

If everything checks out, which it almost always does, the frames get sanded to remove the Peel Ply texture (click to enlarge).

They also remove any excess carbon from the insides of the headtube or BB shell to make sure they’re all in tolerance. The holes are cut for the cable stops and bottle bosses. Those parts are pressed or bonded in place, then it’s racked to await paint and final finishing…which we’ll show you tomorrow in Part Three.

More Feature Posts Factory Tour – Guru Cycles, Part 1: Office Visit, Carbon Bike Design & Stress Testing - via Bike Rumor

Factory Tour – Guru Cycles, Part 1: Office Visit, Carbon Bike Design & Stress Testing

posted by Tyler Benedict - December 10, 2013 on Bike Rumor

For quite some time we’ve been talking to Guru Cycles about visiting their headquarters and factory near Montreal. Following Interbike, we finally made it happen, giving us the opportunity to see close up how they make the amazingly light ~670g Photon HL carbon frame. I even got to ride one, as well as see how they come together from the time you talk to your shop until the time it’s boxed and shipped. And every last bit of the frame is made there in their own facility. Rolls (not tubes, mind you) of prepreg carbon comes in, frames go out, and that goes for all of their carbon bikes, not just the top of the line HL.

They also make titanium bikes, which will be the subject of Part 3. Here, and in Part 2, we’ll show you how the carbon frames are designed, made and tested, along with an overview of their entire operation. Come along, join the ride…




The first stop is the showroom, upstairs from the production floor and adjacent to the offices. One or two iterations of each model sit dressed to impress.



Inside the glass room is their fit studio. If you’re in the area or willing to travel because your own shop can’t do the fit, they’ll be happy to dial you in on their Guru fit device.



Behind the fit station is their workshop, and across the floor is their cafe. Not sure if there’s free coffee for all, but the espressos were flowing when I was there. C’est bon! On the right is the conference room, where we spotted the requisite-for-any-factory-tour prototype sketches:






Behind the cafe are all the offices, with sales and customer service taking up the middle space. Above is the graphics department, where they make your wildest (paint scheme) dreams come true. They offer quite a range of colors, but can basically do anything you’re willing to pay for:



The Guinness bike was reportedly quite a fun project.



Once the graphics for a customers’ bike are finalized, they’re cut and prepped in a bundle and head over to the paint and finishing to await the frame. That’s Jodi, their marketing/PR director and my lovely host for the visit.

CREATING A BICYCLE

The process begins with a good, professional fit from a certified fitter. That’s why they developed their own Guru sizing system, which has since been sold to the Cannondale Sports Group. It’s one small example of the innovation that comes out of this small Canadian company. Another is one of the first production sub-750 gram frames with the original Photon. And the new Photon HL that can come in just under 670g for a stock H1 in size 54 thanks to some trick carbon cutting (you’ll see).
Start to finish, it’ll take about 3-4 weeks to make a Photon. Actual hands on time is at least 20 hours -more for the HL- with a good bit of that time used for drying and curing. Then add a week for delivery.



Once the rider’s measurements, body metrics (weight, height, etc.) and preferences (stiffness, comfort, riding style, etc.) arrive, they’re plugged into Guru’s software. After dropping in the numbers, the system warns of any potential issues like toe overlap. If it’s all clear, they generate three drawings: A rendering to show the customer, a build sheet showing dimensions with the seatpost, stem, fork and other parts, and a geometry chart for the actual frame builders to use. That gets approved, then it generates cut patterns for the carbon and we’re off to the cutting room.



Each tube and section of the frame has it’s own specific group of plies.



It’s plugged into a router that cuts the shapes from rolls of prepreg. They cut parts to make every bit of the frame, including the tubes. That makes them one of the few brands that actually makes their own carbon tubes in house. They use two different grades of prepreg carbon -standard and ultra high modulus- and control the layup from start to finish.



This is one tube. Shapes are cut in exact designs that minimize overwrap where it’s not needed, which saves weight and waste. It makes for much prettier layups, too. They’re cut and stacked so the fabricator can work on a single tube or part at a time.



One of the secrets of the HL’s amazingly low weight is the patent pending striped design. The finished tubes look like strips of carbon were laid up over the rest, but in reality strips are removed from the outer layer. Believe it or not, that saves up to 60g per frame, all without sacrificing strength or rigidity. They use this pattern across most tubes on the frame.
They weigh and QC-check each tube and part before molding, after molding and various other times during the process to make sure things are in spec. Each frame supposedly comes out within 5g of target weight before it goes to paint.



Once cut, the pieces move next door to the clean room where everything’s laid up around latex bladders.



These are bladders for the headtube and seatstays.



The bladders are filled with glass beads to give them enough shape to wrap around, then emptied before going into the molds, which are machined in-house out of aluminum. They use aluminum because it’s easier to machine and lighter (easier to carry the molds around by hand – you’d need a lift to move steel molds). Since they’re a comparatively small volume operation, they don’t need the durability of steel molds.



The exception to that method is the seat tube and bottom bracket, which is what’s being fabricated above. The seat tube and bottom bracket shell are wrapped around a metal mandrel covered by a bag, then wrapped together before going in the mold. This creates a co-molded part with the tight tolerances requires for pressfit bottom brackets.



They admit the silicone bladders result in a smoother (near perfect) interior wall, but in order to co-mold the piece the way they do, it required a bag. So, they chose the smallest bag they could that most closely matched the size of the mandrel to reduce wrinkles as much as possible. It’s removed after curing, so all that’s left is the carbon. Taking it out saves about 15g. Yep, I’m just teasing the actual wrap method here – the complete carbon bike construction follows in Part 2. But, we’ve gotta get things ready first.



While we’re looking at molds, here’s their collection. The ones pulled out are for their TT bike (which was updated at Interbike) and uses a lugged construction method rather than the Photon’s lighter-but-more-labor-intensive tube-to-tube build. The lugged construction lets the parts sleeve together quickly for easier, more price-competive builds.



This adjustable mold lets them tweak the size of the tube based on the customers’ dimensions. Also made in house, just like all their tooling:



All of the dies and other bits used to craft their frames are machined in house. Having it all under one roof allows for quick testing and development. From the time they develop a concept, it’s on the factory floor being prototyped within a couple weeks. And if they need to change something or want to test an idea, they can machine the tooling or lay it up quickly and integrate it into production within days.



They have a lot of bladders for different size and type frames.



The carbon tubes on the left are house-made tubes for a Photon SL, which gets custom geometry but uses “stock” tubes.



Once the mold or bagged mandrel is wrapped, it’s inflated to compress the carbon against the alloy mold. Those are clamped together and placed in the heat press. That machine compresses the molds with 20 to 25 tons of pressure, then heats them. Once the temperatures are correct, which is monitored by a computer, air pressure is put in. Both temperature and pressure are ramped up gradually, reaching up to 135 degrees C and 120-130 psi. The whole process takes 30 to 40 minutes for the larger molds, much less for the smaller molds since they heat up quickly. The curing process is customized for each tubeset based on the makeup of the fibers and resin type. Just another example of how they control the process for every bike. Once this process is over, any resin flash is removed, tubes are sandblasted to remove any residue, and they move on to the mitering station. As parts are finished, they’re assembled into a bin for initial tack up, then come back to the clean room for the outer wrap that actually turns the parts into a whole. Again, Part 2.

TORTURE TESTING

Fast forward to the complete frame. Once it’s through production, Guru engineer Nicolas McCrae will occasionally pluck a frame from the line and bring it here to die. They have four different test rigs, which can all be set up with different load cases to test deflection on specific parts of the bike. They can mimic tests used by Asian manufacturers and Tour Magazine, plus their own protocols.



This bike was being tested for front triangle flex. McCrae built it up normally and tested it to pass. Then he added a couple layers of strategically placed (he wouldn’t tell me where – top secret R&D and all) high mod strips of carbon and increased front triangle stiffness by 30% for a weight gain of just 2%.



He also tests prototypes and new layups. This woven pattern did well, but isn’t practical from a production standpoint. Or at least that’s the story McCrae’s sticking to. There were some other ones we couldn’t photograph.



Ultimately, the physical tests are done to verify the computer simulations and virtual designs.
The other side of the equation is the torture testing, shown on the right. Their machine simulates 100,000 left/right pedal revolutions with a 1,100 Newtons of force (242 pounds) on each side. So, that’s like a 240lb person putting 100% of their weight and 100% of their effort riding routinely for years. McCrae said it’s far more load than any bike will see in the real world. He adds in a short burst of 1,700 Newtons for 4,000 cycles (375 pounds) just for fun, too. He says if a frame passes the first 4,000 cycles, it’ll likely last a couple million cycles. All of their bikes, even the insanely light Photon HL, pass the test easily.