2014 Giant TCX: Press-fit bottom bracket replacement

It started with clicking as I pedaled away on Hyro aboard the indoor trainer.

It was always on the drive side, and it corresponded with applying downward pressure on the cranks from just beyond parallel to the ground. I wasn’t totally sold on it being a bottom bracket problem yet, as I could get it to go away with slight changes to my pedaling stance and force application on the pedal face.

The clicking got to a point where it became a regular occurrence and could no longer be ignored. One Saturday morning, I decided to finally get around to replacing the bottom bracket. Perhaps I was unconsciously putting it off, daunted by the procedure, but I suppose there’s a first time for everything. After all, it had been seven years on this current one.

At least I was prepared; I had a smattering of tools already in storage for this job. Accessing the bottom bracket always necessitates removing the crank, so I did just that. I would also need a new bottom bracket and the tools for removal and installation. A Shimano BB71-41B unit had been in my tool closet for years, and so was my Wheels Manufacturing PRESS-7 universal bottom bracket press and Park Tool BBT-90.3 tool set for BB86/BB90/BB92/BB95 applications. I had just never gotten around to using all of them until now.

With the crank out of the way, hammering out the old bottom bracket came next. Half of the BBT-90.3 is a remover tool, which is a steel tube closed at one end, and open with four flared fingers at the other. You push the remover tool through the bottom bracket shell, compressing the fingers until they go through the inside of the bearings and snap back into their flared-out position. Then you take a hammer and bash away at the tool’s closed end, its fingers pushing on the bearing cups with each blow until they fall out. I won’t lie – this feels totally wrong.

After some percussive persuasion, I got the old bottom bracket out and performed a postmortem inspection. Sure enough, the non-drive bearing still spun smoothly, but the drive-side one had telltale rusty brown traces in its inner race, and the whole thing felt rough and gritty to spin. This bottom bracket was truly well past its prime.

At this point I could now see into Hyro’s bottom bracket shell. As it had housed seven-year-old dirt and grit, it needed cleaning in preparation for the new bottom bracket, . A smearing of fresh grease later, it was now ready to accept a new bottom bracket – and time to truly test the PRESS-7.

Check out that funky green Shimano grease

While Wheels Manufacturing don’t recommend using the PRESS-7’s universal bottom bracket drifts for anything other than their own bottom brackets, they matched up nicely with the Shimano BB71-41B, carrying the bearings by their inner races. After assembling the tool inside Hyro’s bottom bracket shell, it was just a matter of turning the handles inward until the bearing cups sat flush on the lip.

Once the lip on the bearing cup meets the bottom bracket shell, you are done.

They got pressed in smoothly, simultaneously, and straight. Couldn’t really ask for more than that.

All that’s left is to reassemble the crank and ride the bike again – now free of clicking, creaking, or otherwise discordant noises as I pedal.

Frame builder pet peeves: Cannondale

American cycling brand Cannondale is beloved by many, sometimes with a fanaticism not obvious from other large marques. However, having started cycling well after the brand had established itself as a mass-production juggernaut, I’m afraid I don’t really see what the fuss is about.

While Cannondale is rightly applauded for stubbornly sticking to its aluminum alloy guns, there are quite a few reasons why I can’t really support the brand with my own cash.

BB30…

In a bid to increase the stiffness of cranks while making them lightweight, Cannondale introduced the use of aluminum in the crank spindles. Due to the lower density of the material versus steel, they increased the spindle diameter to 30 mm, which required creating a bottom bracket shell to house this new spindle and the bearings it spins within. Lo and behold, the press-fit standard called BB30 was born, and Cannondale opened it up for other frame builders to use in 2006.

Instead of screw threads, BB30 uses bare cartridge bearings pressed into a bottom bracket shell that’s ever so slightly smaller, held in place by a circlip on the inside. By keeping the bearings close together (spaced 68 mm apart for road bikes, and 73 mm for mountain bikes), a bike with a BB30 shell keeps a narrow Q-factor, which is a personal-preference bike fit metric that determines how widely set apart your legs and feet are while pedaling. Couple that with a light yet stiff crank, and you get power, comfort, and control.

A PF30 bottom bracket getting pressed into a frame. Unlike BB30, PF30 uses nylon cups (in black) to take up any slack or bad tolerances between bearings and frame.

For BB30 to work right, it relies on the bottom bracket shells being machined to very exacting tolerances. Done correctly, a press-fit bottom bracket system like BB30 should not be problematic. However, this is where it starts to fall on its face. Opening up the standard to other framebuilders, those with less manufacturing precision, may have jeopardized the popularity and engineering soundness of BB30, as loose tolerances and poor bearing alignment can cause the dreaded creaking. Worse, the bare metal cartridge bearings don’t have a cup they sit in to take up the slack.

…AND ITS CHILDREN

Yes, BB30 begat children. BB30A was released in 2014, and BB30-83Ai in 2017.

The 2014 Synapse frameset introduced BB30A to the world in 2014.

I understand that BB30A and BB30-83Ai each introduce engineering solutions to problems. BB30A extends the 68 mm BB30 shell and adds 5 mm, much like on a mountain bike. However, unlike on mountain bikes, it adds all of this 5 mm on just one side – the non-drive side – hence the “A” designation for “asymmetric.”

BB30-83Ai is similar in concept. Remember the narrow Q-factor benefit promised by BB30 and its 68 mm bearing spacing? That’s proven short-sighted and very restricting for cyclocross and gravel bikes, which require the capability to fit ever wider tires. Cannondale ended up widening the bottom bracket shell to 83 mm, giving them more room to attach the chainstays while increasing tire clearance at the rear and keeping stiffness good.

Released in a time when bikes already have way too many bottom bracket standards for the average consumer to keep track of, perhaps this is Cannondale simply being inconsiderate IMHO. Both BB30A and BB30-83Ai require new-ish cranks to work; older BB30 units will simply be too short. Add to that their known inconsistencies and bad tolerances, and you’d think Cannondale would have learned their lesson by now…especially when BB386EVO/BB392EVO, a bottom bracket standard designed to be as compatible as possible with everything else short of reintroducing screw threads, already exists.

INCONSISTENT MANUFACTURING?

That would have been enough to end, but it’s a different story altogether when it’s Cannondale themselves that have bad manufacturing tolerances. Hambini, a small British engineering firm which specializes in fanatically built bottom brackets, has a video showing just how sloppy and inconsistent Cannondale’s manufacturing has gotten – in some cases, even worse than Chinese “own brand” frame makers which have a lot less name recall in the West.

Below is Hambini’s box-and-whiskers plot of bottom bracket diameters and tolerances, which he constructed by measuring the bottom bracket shells of a large number of frames, across a number of manufacturers. As not all of these frame builders use the same bottom bracket standards (e.g. both Trek and Giant don’t use BB30), he normalized the chart for the 6806 bearings used in a typical BB30 system for comparison purposes. The larger the figure, the worse the consistency of manufacturing. Ideally for a manufacturer of BB30 bikes, you’d be close to the BB30 specification of 41.96-41.98 mm.

Considering they introduced BB30 to the world, Cannondale has a pretty bad showing here. The upper limits of the box plot go too far past 41.99 mm, with outliers even reaching 42.01 mm…meaning they’ve got bikes out there with pretty sloppily made bottom bracket shells.

Ever wondered why so many complaints arise in local bike groups about BB30 bikes and cranks creaking? Now you know. Perhaps this is because no Cannondales are actually made in America nowadays any more?

MORE FRAME MAKERS ARE REDISCOVERING ALUMINUM

For a long time, Cannondale’s unique selling proposition was that it could keep committing itself to making aluminum bikes that were not only good; they could even be competitively raced against carbon fiber. In recent memory, the CAAD10 and CAAD12 road bikes are proof of this; apart from material choice, these bikes share a lot of their geometry and design choices with the brand’s premier carbon fiber race bike, the SuperSix Evo.

Junction of the headtube, downtube, and top tube of a 2018 Trek Emonda ALR. Yes, this bike is made of aluminum. Photo courtesy CyclingTips

They’re not the only player any more though. Specialized has been promoting Chris D’Aluisio’s SmartWeld technology on its aluminum bikes for years now, although perhaps due to premium pricing they cannot gain the same top-of-mind traction Cannondale does. Recently, Trek has bet on next-level aluminum metal working with its second-generation Emonda ALR lightweight road bike sporting similar Invisible Weld Technology, featuring tube junctions so smooth, and welds so inconspicuous, you’d swear the bike was made of carbon fiber.

IS CANNONDALE THE BIKE EQUIVALENT OF SONY?

What do the two brands have in common? They have an unhealthy appetite for creating proprietary parts.

Now, this isn’t really a new thing, and I think proprietary parts lie on a spectrum of hassle. For example, seatposts have been proprietary for a long time; just look at any aero bike or time-trial bike. Also, more and more brands seem to be introducing their own take on a D-shaped seatpost to encourage more flex and comfort. Seatposts are relatively low on the hassle spectrum, though, especially if you take yours out every few months to avoid seizing inside your seat tube by galvanic corrosion.

To properly fit the rear dropouts of a 2018 Cannondale SuperX, a wheel must be dished asymmetrically.

Wheels and hubs, on the other hand, are just about the worst place on a bike for proprietary restriction. And this is where Cannondale played its most recent hand with their 2018 SuperX cyclocross bike, which requires its wheels’ spokes to be dished a certain way vs. normal. Okay, so it makes for a slightly stronger wheel and shorter chainstays, but all of a sudden, the wheels you used for cyclocross may no longer work if you have a SuperX or two or five on your cyclocross race bike fleet, unless you get them all re-dished to fit. If you don’t know how to true wheels or re-dish them yourself, you can imagine how high that ranks on the hassle spectrum.

Cannondale’s 2015 release of the Slate was a risky move that eventually paid off.

Had times not changed, I would have included the 2015 introduction of the Slate, Cannondale’s strange gravel bike equipped with a Lefty fork, in this point. At the time, 650B (27.5″ or 584 mm bead seat diameter), as a wheel and tire size for road bikes, was largely a fringe offering used only by randonneurs and bicycle tourers. Fortunately, Lefty forks have been around long enough that people have gotten used to their quirks. The arrival of the Slate and its reintroduction of 650B also coincided with the boom in gravel bikes, which led to a notable increase of wheel and tire options in that size and around the 47-55 mm width, as people found out that this combination yielded a smoother ride at the same effective diameter as a 700C x 22-25 mm wheel/tire combo.

CONCLUSION

At long last, a Cannondale I am finally comfortable recommending: their Topstone aluminum gravel bike.

Don’t get me wrong. I admire a lot of what Cannondale does. Their affinity for aluminum and willingness to keep developing bikes with it while pushing its metallurgical merits is exemplary. A lot of the innovations they introduced are also legitimate solutions to engineering problems. However, from a DIY maintenance perspective, I find it very hard to recommend their bikes, and I believe buying them means telling Cannondale that there is nothing wrong with their approach. Personally, I wouldn’t entertain a Cannondale unless it had a threaded bottom bracket shell…and all credit to them for finally taking notice, as evidenced by their Topstone gravel bike.

Shopping for a road bike? Here’s a checklist

Sometime last year, I wrote about the things I would look for if I was to buy a folding bike again. This time, I’ll talk about the things you’ll probably want to look for if you were to buy a road bike, a cyclocross bike, or a gravel bike.

HOW DOES THE FRAME FIT YOU?

Most folding bikes can accommodate a large number of physiques because of the telescoping seatpost and handlepost; many advertise fitment of riders from 4’9” to 6’1” (144.5 to 185.5 cm). With road bikes, by comparison, bike fit is a lot more critical – so much so that an entire bike-fitting industry has popped up in recent years just to address the physical and kinematic relationship between rider and bike.

The geometry chart for Giant’s TCX from 2014. This is a pretty basic example; other manufacturers go into more detail with things such as head tube angle and bottom bracket drop.

It all begins with getting the right size bike for you. Most bikes bought off the shelf come in a range of sizes. These typically differ in their seat tube length (abbreviated ST) and top tube length (TT). For frames with non-horizontal or sloping top tubes, it’s the effective top tube length (ETT) you’re interested in. All of this is written on a bike’s geometry chart, with values per size of bike.

For newbies to road bikes, it’s best to swing your leg over the actual bike and check the fit yourself. With more experience, you can start looking into the reach and stack figures for the bike – the vertical and horizontal measurements relating to the bottom bracket and handlebars. Since reach and stack are measured from the same locations across all bikes, this provides an instant basis for comparison between them.

MIND THAT FRONT END

Related to bike fit is the head tube length (HT), which determines your riding position on the bike.

Long head tubes put you in a more upright position, and don’t require as much of your lower back. For this reason, they are a fixture on endurance bikes which are meant to be ridden for hours on end, and such bikes are better for those of us without sufficient flexibility.

By comparison, short head tubes give you a long and low position best for racing. This benefits aerodynamics, as reducing your frontal area decreases aerodynamic drag, making you more efficient while pedaling at sustained high speeds. The drawback is that you have to be able to sustain such a low position, not something everyone can do in comfort.

HOW WIDE OF A TIRE CAN YOU SMOOSH INTO THE FRAME?

Hyro can fit 32 mm tires with lots of room to spare – par for the course for a cyclocross bike.

These days, sticking wide tires into a road bike to improve comfort is no longer a badge of shame. The professional cycling peloton has done away with 23 mm tires and adopted 25 mm rubber for most races, with even wider options being used for particularly bumpy races such as Strade Bianche or Paris-Roubaix. If a modern road bike frame can’t fit at least 25 mm rubber, I suggest you look elsewhere.

This is where cyclocross bikes and gravel bikes have a distinct advantage. As per UCI competition rules, cyclocross bikes should run a 700C x 33 mm knobby tire, and most cross machines will come with even wider 35 mm rubber as stock. Gravel bikes have even less restriction, generally fitting at least a 40 mm tire with clearance to spare. Notable on both bikes is that they often run disc brakes, which removes restrictions on tire width.

MAKE SURE YOU CAN LIVE WITH YOUR FRAME’S BOTTOM BRACKET SHELL

Hyro has a BB86 bottom bracket shell. The bottom bracket bearings are pressed into the frame.

Bottom brackets and their many, many formats are a potential minefield that I tackled in a previous post. Each has its positives and negatives. So far, though, the good old 68 mm BSA threaded bottom bracket shell is the resurgent choice, after a decade of complaints on the various press-fit formats, and for good reason: it just works.

Mang Boy of LifeCycle setting up the bearing press for Hyro’s bottom bracket.

That’s not to say that frames made with the press-fit bottom bracket standards are all bad. My TCX has a BB86 bottom bracket shell, and so far I have had a decent enough experience with it, paired with FSA and Shimano cranksets. Anecdotally it’s the BB30 and PF30 formats that seem most problematic.

HEADSET CHOICES

The frame determines the kind of headset it uses. There are bikes that use pressed-in headset cups, while others have the cups integrated into the head tube.

The TCX has integrated headset cups machined into the head tube. Its 1-1/8″ and 1-1/4″ bearings support a fork with a tapered steerer tube.

This also influences the size of the headset bearings themselves. The most common combination of headset bearings I’ve seen in recent years is a 1-1/8” (1.125”) top bearing and a 1-1/4” (1.25”) bottom bearing – a headset to accommodate a fork with a so-called “tapered” steerer tube. Giant’s higher-tier bikes have the “OverDrive2” headset system, which makes use of a 1-1/4” (1.25”) top bearing and a 1-1/2” (1.5”) bottom bearing. This is supposedly to increase front-end stiffness and steering precision, but it also means headset bearings can be a little tougher to find once you need a replacement.

DISC BRAKES OR RIM BRAKES?

The decision between rim brakes or disc brakes is a major influence on the frame choice, as very few road bikes can support both (Orbea’s 2014 Avant series being a rare example). Disc brakes put more stress onto the non-drive side of the frame, so these areas have to be beefed up accordingly. Bodging a disc brake conversion on a rim brake bike can end in a bent fork or rear triangle, so you will usually have to choose between one or the other.

One argument for disc brakes is that they will support wider tires by default, as there is no longer a brake caliper straddling the width of the wheel and restricting it. Caliper rim brake bikes tend to max out at 28 mm or 30 mm rubber; cantilevers or mini V-brakes accommodating around 35 mm.

Hyro, my TCX, uses Post-Mount hardpoints for his brake calipers. This can still be found on some cyclocross bikes.

This Eddy Merckx Mourenx69 road bike uses Flat Mount hardpoints, where the mounting bolts go all the way through the chainstay. These days, this is the norm for disc-braked road bikes.

A final concern for disc-brake bikes is the caliper mounting system. Early disc-braked road bikes from 2014 cribbed the Post Mount system from mountain bikes, but Shimano has since successfully pushed for the adoption of Flat Mount – which is what you will see on modern bikes.

WHAT OTHER FEATURES DOES THE FRAME SUPPORT?

We’re delving into the realm of “nice to have” features here, but they can be a deal-breaker depending on the kind of riding a cyclist has in mind.

Many bikes still don’t offer eyelets for mounting of full-length fenders.

Personally, any road bike with no fender eyelets and rack mounting points is a no-go – automatically disqualifying a lot of options at the time I was shopping around for one. While Giant bestowed threaded eyelets on my TCX’s dropouts and fork, it was still missing mounting points at the seatstay bridge and chainstay bridge, so I had to bodge those up.

My folding bike Bino is an example of one without a brazed-on tab for a front derailleur. A front derailleur adapter wraps around the seat tube as a substitute.

Front derailleurs with braze-on mounting are prevalent almost due to preference, but not all road bike frames can mount them straight away as they don’t have the riveted or brazed-on mounting tab on the seat tube. Typically these bikes have round seat tubes, so making use of either an appropriate front derailleur adapter or a band-on front derailleur should solve this issue.

DID YOU NOTICE ANYTHING?

You may have noticed that I did not once touch on the groupset, wheels, tires, or personal-fit items like saddles, stems, and handlebars. While these are major considerations, they’re also easily replaced in case something problematic happens – almost all of them are wear items anyway. By contrast, the frame is the heart of the bicycle; if you replace the frame, you might as well have bought an entirely new bike.

I also spy a lot of questions being asked on forums and Facebook groups about frame sizing, bike fitting, headsets, or bottom brackets, when these are all highly frame-specific items and have to be taken into consideration when actually buying a bike in the first place. I find it’s much better to buy a bike knowing full well what its frame’s quirks are so that you fully understand what you’re getting into – especially if you intend to perform your own maintenance.