Bearing Swap - 2020 Santa Cruz Tallboy (4th Gen)
It was nowhere near time. I was quite sure there would be no need to do any bearing maintenance to the Tallboy, which had been in our stable for about a year. Santa Cruz bearings are famously well-protected from the elements, and the lower link bearings are bathed in grease that can be refreshed easily using the grease gun equipped with a zerks fitting. I however, was eager to participate in the process to see what tools were required, and how I could mess it up.
Going into the bearing swap on the Yeti SB150, over confidence was my fatal error. I assumed I had all the correct tools and the process would be simple. Unfortunately these notions worked against me. I was surprised when I hit roadblocks and frustrated when things didn't go my way. Worse, my reasoning skills suffered as a result of my hubris.
When I know something is going to be a challenge, or I'm uncertain about the required steps, I slow down and deliberate more effectively. Rather than jumping in like a puppy at an orgy. Unfortunately this lesson wasn't learned before I began the same task on Santa Cruz's excellent new Tallboy. Once again I was given tools from the brand, and I assumed the task could be completed entirely with those tools. Again this didn't turn out to be accurate, in my case at least, and I fucked up. As you'll see. This fuckup was reversible in this case, but it could have been much worse. When you see it (no skipping ahead) you'll ask yourself, what the fuck was he thinking? Which is what I have been asking myself since.
Disassembly is relatively straightforward on the Tallboy. You can visualize exactly what you are dealing with (despite the lower link being partially concealed) and tackle things in any order you like. There is a top link and a bottom link and they are independent of each other. Even better is that the entire disassembly can take place from one side of the bike - the non-drive side. You can even leave the cranks on, which I did. As I recall, this one-sided operation was incorporated at the suggestion of Jason Marsh, Greg Minnaar's mechanic, and it's a thing of beauty.
I started with the top link, probably because it looks dead easy. In the end this wasn't entirely true for me. Removing the upper link involves removing a couple of bolts, and a stickler for accuracy might proclaim Santa Cruz's one-sided claim isn't the whole truth because there are bolts on both sides of the upper link. Alas, SC prevails here because you could easily reach through the main triangle or above to get to the bolts on the upper side. I just spun the bike around however, without the time constraints of a World Cup or bike shop mechanic.
Once the link was off, the removal of bearings was meant to be straightforward, and for the most part that was true. One end of the top link has a yoke and the other does not, which makes each tricky for different reasons. I really don't like pushing out bearings with a punch, but of the tools I had at my disposal, this was the only option for the lower end of the link. Neither of the pullers I had with expanding jaws would fit the diameter of these bearings, so hammer and punch it was. I used a couple of cloths doubled over in the vise, in place of soft jaws, which I do not own, and popped the bearings out easily. The diameter of the sleeve between the two bearings doesn't leave enough edge exposed to get purchase, but the sleeve has a clever cut out to allow you to get the punch aligned and then pop out the first bearing. After that the sleeve drops out and the exposed second bearing is a piece of cake.
Pulling the bearings on the Yoke side wasn't too bad either, but it took me a few attempts to get just the right tool combo. When it came time to press in the bearings I was scratching my head. For a similar operation, Yeti provided a soft-armoured sleeve to give purchase to the press. Of the sleeves I had, none had both enough inner diameter and the right shape to press against the outside of the linkage without slipping and marring the anodizing. But I had another plan. A plan so cunning, so ill conceived, and so stupid, that the result was entirely predictable. I wish I could blame the beer, or other consumables, but the beer was just cracked and nothing else was on board.
I had enough sense to attempt perfect bearing alignment, realizing the force of the press on the unsupported wings* of the yoke could bend them inward if done improperly. Despite this, I began turning wrenches and became lost in thought. I looked at my progress absentmindedly, and things didn't look quite right, but this failed to stop me or register alarm until later; when it was crushingly obvious things were not right. Watching yourself damage a forged, proprietary aluminum part on a beautiful and expensive mountain bike frame, is like noticing you are drilling a hole in your thumbnail. I couldn't quite believe what I had done, despite the compelling evidence in front of me, and looking away was impossible. In case it wasn't perfectly clear, I screwed this up and there was nothing wrong with the tools or the link itself.
*I have no idea if these are actually referred to as wings, but it seemed like a reasonable descriptor
I backed everything off and rejigged the tools with the hope that what was done could be undone. The undamaged ear supported the press and the bent-side slowly levered until it reached its original angle. When I tried it on the frame the first time, it was miraculously a perfect fit. I hadn't quite snatched victory from the jaws of defeat, but the bike would be usable in the short term.
I had to take a long hot shower after the yoke mess and I returned chastened but hopeful I could turn things around. I realized later that this strategy would have worked if I'd used the frame as a support for the yoke so there would have been no gap between . As it was I rejigged the tools and pressed each individually and without drama. I pressed the new bearings smoothly into their seats on the upper link using the Santa Cruz tools and then replaced the upper link, careful to grease the shoulders and the wedge, but not the collet which requires friction to remain in position. Some blue loctite was applied to the threads, but I was just guessing at torque values. The most recent Santa Cruz guide for this operation quotes 13.6-15.8 N.m (120-140 in-lb) for the upper link bolts and 6.8 N.m (60 in-lb) for the collet axle. The wedge and bolt lock the collet in place, without further tightening the axle onto the bearings. These should be torqued to 9.0 N.m (80 in-lb).
Seb Kemp recommends unfastening the rear shock mount first, and my recommendation is removing the front mount second. After that, removing the lower link requires first removing the expanding wedges on the two mounts, each held in place by a 5mm hex bolt. The wedges should come out easily, but just in case they are keyed to a 6mm hex to give you some purchase. After that use an 8mm hex wrench to remove the collet axles. These also came out easily for me.
After pulling out the fun knuckle, remove the dust covers on the four bearings and do a little inspection. Do the bearings look fulfilled? Well nourished? Do they yield willingly to your twisting touch? The bearings on 'our' Tallboy presented clean and fresh looking lube under the dust covers, despite never having had a tender service caress before this, and they turned enthusiastically and without resistance. This bike has spent time in Scotland, and all over southern B.C., but mostly on the North Shore over a nasty, snotty winter. It was also often subject to rough play, but the bearings and grease looked brand new.
When it came time to push the bearings out of the lower link, I wasn't pleased with any of the tools in front of me. I wanted to avoid the vise and punch, but none of the other tools would capture the narrow exposed edge between the inner bearing race and the inner sleeve. Luckily the expanding collet press* from the Specialized FSR kit fit perfectly, and the bearings popped like pits from a cherry.
There was more grease behind the bearings, from the grease port that distributes lube to the open back side of each bearing. It was pristine. Pressing the bearings in, without unsupported yokes to worry about, was a piece of piss. Getting the lower link back in place took some futzing around. A little grease under the dust covers helps them stay in position as the mechanism is inserted into the frame. After that, it's time to replace the collet axles, re-install the rear shock, rear mount first, and admire your work with smug satisfaction.
Santa Cruz will send you replacement bearings for the lifetime of your frame - for free. Install is either up to your or your local bike shop. All the info for US or Canadian riders is here. Otherwise, contact your Santa Cruz distributor through your dealer. You'll have to wait until the dust settles on COVID-19 and people go back to work, but Santa Cruz promises to get your bearings in the mail in under 48 hours under normal circumstances. If your bike is from 2017 or earlier, you may need to adjust your angular contact bearings. More recent frames have radial bearings that do not require adjustment.
Note; your local dealer will be more than willing to do your bearing swap,* assuming a swap is actually necessary. It may be that, like mine, your bearings are perfect or they may simply need some more lube. You can get some idea of bearing condition by removing the shock and rear wheel and cycling the suspension through its travel. If it is silent and without friction of vibration, you are likely in good shape, although a closer look never hurts. Lubing the lower link with a grease gun will keep those vulnerable cartridges rotating smoothly.
*labour charges will apply unless your shop has a different policy
Santa Cruz doesn't have instructions for any bikes beyond 2018, but the info for the Nomad transfers well to the newer models. Hopefully there will be a video available to take you step by step through the Hightower, Tallboy and Megatower soon, but if your bike is that new you probably don't need much more than an inspection or, at worst, a shot of grease. You can also get all the replacement hardware for your bike and Santa Cruz promises to keep stocking those parts for at least ten years.
I may have made this look difficult, but that just means I've vetted the mistakes for you. Really this isn't a tough job at all with the right tools, which Santa Cruz will be happy to sell you once staff returns to the office in Santa Cruz.