PSA - Common Misconceptions on Installing THM Clavicula SE's

[jpeterson1012]

I could not find any concrete information during my preparations for installing my THMs, also, the preload configuration on these cranks is very different compared to your run-of-the-mill cranks, so I figured I'd make a little PSA/FAQ thread on what you should and shouldn't do with these cranks.

TLDR: If in doubt, just use the THM BB. If this post makes little to no sense to you, have a bike shop install them.

Q1. Can I use X bottom bracket with Clavicula SE's?
Most likely no. For example, there is one thread on here claiming you can use ceramic speed BBs with THMs, supported by the Hambini himself. However, it should be noted that that is with a 386EVO frame, which doesn't suffer from wildly varying bottom bracket assembly widths (over-bearing-width) since it is basically the widest BB these cranks will work with. If you're on a BB30 or PF30 frame, chances are it's a big fat no. That has to do with the fact that the Clavicula SE's design makes it very sensitive to over-bearing-width due to the two-stage taper of the spindle along with the tapered wedge on the non-drive side (THM specifies a 68mm +/- 0.2mm for their BB30 and PF30 BBs)

I've attached a couple of drawings below to illustrate, note that the tapers have been significantly exaggerated, and some trivial components have been left out for simplicity's sake.


Pic 1: This is "just right," where the over-bearing-width is 85.5mm. The tapered wedge is sitting in just the right spot to both apply preload, and support the NDS bearing radially by expanding ever-so-slightly against the taper (as in, make sure it's making even contact with the spindle all the way around)


Pic 2: This is when your over-bearing-width is too wide, either due to poor frame tolerances or because of a non-THM bottom bracket. For example, many generic PF30 bottom brackets have an over-bearing-width of between 86.5-89mm, which is too wide for this particular crankset. When the BB assembly is too wide, the tapered wedge does not make contact with the spindle before bottoming out against the bearing. This results either in poor contact, and thus support, or in bad cases, excessive radial (up/down) rocking play on the NDS which will ruin your crank spindle over time.


Pic 3: This is a too narrow scenario. In this case, the tapered wedge has maxed out on the taper and cannot sit any further in, yet the flange of it still does not make contact with the frame. If you try brute-forcing the tapered wedge any further, it will split. This configuration results in side-to-side play and no bearing preload, which will wear your spindle over time, but more importantly, chew through bearings like nobody's business. Fortunately, this can be somewhat corrected using appropriate spacers, shimmed up in very small increments.


Pic 4: This is a case when one tries to use an inboard PF30 (whole bearing cup sits inside frame) BB, or just use in-frame BB30 bearings with the Clavicula SE's. The gray blocks are the spindle spacers. Note how the DS bearing sits on the tapered portion of the spindle, and the NDS bearing is very poorly supported by only the tapered wedge. I learned this the semi-hard way by buying a set of inboard BBs and nice bearings, then having to toss them aside when I received my cranks


Q2: Ok then, can I use [insert brand] ceramic bearings with these cranks even if I'm using the THM BB?
Yes if you're not on BB86. See this post viewtopic.php?f=3&t=161073&p=1631158&hi ... 6#p1631158 when it comes to BB86 (they use a proprietary angular contact bearing, apparently). THM offers ceramic versions, but otherwise, if you want to use your own choice of ceramic cartridges, you'll just have to knock the original ones out. I'm surprised nobody's mentioned it yet, but THM's bottom brackets (excluding BB86) use standard 6806 cartridge bearings.

The default bearings that come with their BBs are stainless steel, which aren't great TBH. SS bearings are softer than normal alloy steel bearings and have issues with galling, while minor damage in regular steel bearings tend to 'wear-in' over time. The default bearings also come with non-contacting seals, which has slightly less friction but don't last as long and results in the need for some heavy dust covers (6g for the pair). For those reasons, I would swap those out for some NTN/SKF 6806LLU (contacting seal) bearings at the earliest signs of degradation, and then replace the heavy dust covers with a pair of 1-1.25mm nylon or delrin spacers instead (only 1.7g).

Q3: Are there any BB tool alternatives?
Nothing "standard" that I know of. THM BBs have 16 notches, a major diameter of 46mm, and a minor diameter of 44mm. To my knowledge, nothing park tool makes will fit. Only a dedicated tool will do THM BB's unfortunately. If you're in Europe, OEM ones are pretty easy to source. If you're in North America, Abbey Tools makes one that will fit. It is not on their website (as of 1/23/2022) for some reason, but I'd email them about it. Madcow over at FairWheel Bikes sells the Abbey ones too.

That's it for now, will come back to add stuff if necessary.

[Coolcat]

Great post. I consider buying THM cranks and this is good to know.

[mashiehood]

spot on - i hve two installed one on my moots witha THM PF30 BB and one on my SL7 with a C-Bear BS30 IS BB. Both work fine

[jpeterson1012]

A quick update:

If you're thinking of using Lightning branded PF30 bottom brackets with Claviculas, I'd advise caution (even though users such as 4Ibanez have recommended it in the past). Despite the over-bearing-distance being pretty close to the required 85.5mm, the set I received indicated some serious quality issues going on over at lightning cycles as of Jan 2022.

I bought a set in the hopes of saving ~25g over the THM, but ended up returning them for a few reasons.

1. Design: I should have thought of this earlier, but the pressed-in cups with outboard bearings doesn't exactly lend itself to great stiffness. The vertical loads placed on the outboard bearings have a cantilever effect on the cups, tilting the cups/bearings on a micro scale (not visible but measurable on a mechanical scale). That "walks" the bearing back and forth on your spindle, making it more likely to wear and/or fret the carbon spindle, which is much softer than the bearing. It's not a HUGE deal, but if you want to maximize the life of your expensive cranks I'd recommend going with something thread-together since they're stiffer (the ideal would be a hambini-style one-piece)

2. Poor manufacturing: To compound the problems described in "1", I was appalled by how poorly the lightning cycles BB was made and assembled. Manufacturing wise, their cups were not even round - they were ovals! Cup "A" had a minor axis of 45.95mm and a major axis of 45.99mm. The minor axis is slightly undersized, so this one fits loosely (not rattling shove-it-in-by-hand loose, but very little force needed to press it in. It would've likely have "walked" if higher-wattage riders had used it. Cup "B" was even worse with a minor axis of 45.97mm and a major axis of 46.12! Cup "B" doesn't even go in the frame. I know calipers aren't the best tool for measuring fine tolerances, but If my calipers can pick up that difference, it just means it's extra bad



3. Poor assembly: As if "1" and "2" weren't enough, the lightning BB had another trap set up for my cranks. The bearings were not even close to pushed in straight. One of the cups (forgot which) has one side of the bearing flush with the lip of the cup while the opposite side sits proud by ~1.5thou (0.04mm). The second bearing had one side sitting flush with the cup while the opposite side sat proud by a whopping 4 thou (0.1mm)! For those who aren't aware, that's a lot, and angular misalignment of the bearings drastically increases wear on the spindle (since it's a slip fit), resulting in the bearing wearing a groove into your spindle regardless of its material). Sure I could've pressed it in the rest of the way myself, but why should I have to when the whole thing is already so fk'd? It's not something that can be easily photographed, but I've marked the high spots with a sharpie in the picture.


Just my sample-size-of-1 review of the Lightning PF30 bottom bracket. But I guess it says something about them when both cups are badly made and assembled. Just because it costs a lot doesn't mean it's always good - don't let your guard down!

[RyanH]

I've had similar issues with Lightning cups, at least what I recall was that I could plop the bearings in without any force and that lead to creaking issues.

A few other installation notes on THM Cranks:

1) Use carbon paste on the splines
2) Use blue thread locker on the preload nut and torx pinch bolt
3) Remove play using preload nut, torque pinch bolt to spec AND then torque preload nut to spec

If you do the above, the arm will not come loose on its own.

[kode54]

Duplicate post. Oops.

[kode54]

Yes, good points @RyanH.

I regards to item #1, put a little carbon paste on the inside splines of the NDS crank arms, otherwise you risk squeezing out excess paste into your BB bearings. I use very little but degrease the splines fairly well so there’s a ‘dry’ grip when clamping the pinch bolt.

[Maddie]

Great post, jpeterspn1012. Every THM crank owner should read this before installation

[Holliday89]

Thanks for this post!! Very helpfull. I went through a lot of the same headaches on my install

[eucalyptus]

I have a set of THM clavicula SE 130 BCD crankset

A road frame with BSA shells.

I also have this bottom bracket, BBinfinite BSA 30mm road BB

Question: are the THM crankset compatible with my BBinfinite BSA bottom bracket? it has a built-in sleeve that is machined in one of the cups.

[wheelsONfire]

Superb goes to the OP

[Sanders2177]

I could not find any concrete information during my preparations for installing my THMs, also, the preload configuration on these cranks is very different compared to your run-of-the-mill cranks, so I figured I'd make a little PSA/FAQ thread on what you should and shouldn't do with these cranks.

TLDR: If in doubt, just use the THM BB. If this post makes little to no sense to you, have a bike shop install them.

Q1. Can I use X bottom bracket with Clavicula SE's?
Most likely no. For example, there is one thread on here claiming you can use ceramic speed BBs with THMs, supported by the Hambini himself. However, it should be noted that that is with a 386EVO frame, which doesn't suffer from wildly varying bottom bracket assembly widths (over-bearing-width) since it is basically the widest BB these cranks will work with. If you're on a BB30 or PF30 frame, chances are it's a big fat no. That has to do with the fact that the Clavicula SE's design makes it very sensitive to over-bearing-width due to the two-stage taper of the spindle along with the tapered wedge on the non-drive side (THM specifies a 68mm +/- 0.2mm for their BB30 and PF30 BBs)

I've attached a couple of drawings below to illustrate, note that the tapers have been significantly exaggerated, and some trivial components have been left out for simplicity's sake.


Pic 1: This is "just right," where the over-bearing-width is 85.5mm. The tapered wedge is sitting in just the right spot to both apply preload, and support the NDS bearing radially by expanding ever-so-slightly against the taper (as in, make sure it's making even contact with the spindle all the way around)


Pic 2: This is when your over-bearing-width is too wide, either due to poor frame tolerances or because of a non-THM bottom bracket. For example, many generic PF30 bottom brackets have an over-bearing-width of between 86.5-89mm, which is too wide for this particular crankset. When the BB assembly is too wide, the tapered wedge does not make contact with the spindle before bottoming out against the bearing. This results either in poor contact, and thus support, or in bad cases, excessive radial (up/down) rocking play on the NDS which will ruin your crank spindle over time.


Pic 3: This is a too narrow scenario. In this case, the tapered wedge has maxed out on the taper and cannot sit any further in, yet the flange of it still does not make contact with the frame. If you try brute-forcing the tapered wedge any further, it will split. This configuration results in side-to-side play and no bearing preload, which will wear your spindle over time, but more importantly, chew through bearings like nobody's business. Fortunately, this can be somewhat corrected using appropriate spacers, shimmed up in very small increments.


Pic 4: This is a case when one tries to use an inboard PF30 (whole bearing cup sits inside frame) BB, or just use in-frame BB30 bearings with the Clavicula SE's. The gray blocks are the spindle spacers. Note how the DS bearing sits on the tapered portion of the spindle, and the NDS bearing is very poorly supported by only the tapered wedge. I learned this the semi-hard way by buying a set of inboard BBs and nice bearings, then having to toss them aside when I received my cranks


Q2: Ok then, can I use [insert brand] ceramic bearings with these cranks even if I'm using the THM BB?
Yes if you're not on BB86. See this post viewtopic.php?f=3&t=161073&p=1631158&hi ... 6#p1631158 when it comes to BB86 (they use a proprietary angular contact bearing, apparently). THM offers ceramic versions, but otherwise, if you want to use your own choice of ceramic cartridges, you'll just have to knock the original ones out. I'm surprised nobody's mentioned it yet, but THM's bottom brackets (excluding BB86) use standard 6806 cartridge bearings.

The default bearings that come with their BBs are stainless steel, which aren't great TBH. SS bearings are softer than normal alloy steel bearings and have issues with galling, while minor damage in regular steel bearings tend to 'wear-in' over time. The default bearings also come with non-contacting seals, which has slightly less friction but don't last as long and results in the need for some heavy dust covers (6g for the pair). For those reasons, I would swap those out for some NTN/SKF 6806LLU (contacting seal) bearings at the earliest signs of degradation, and then replace the heavy dust covers with a pair of 1-1.25mm nylon or delrin spacers instead (only 1.7g).

Q3: Are there any BB tool alternatives?
Nothing "standard" that I know of. THM BBs have 16 notches, a major diameter of 46mm, and a minor diameter of 44mm. To my knowledge, nothing park tool makes will fit. Only a dedicated tool will do THM BB's unfortunately. If you're in Europe, OEM ones are pretty easy to source. If you're in North America, Abbey Tools makes one that will fit. It is not on their website (as of 1/23/2022) for some reason, but I'd email them about it. Madcow over at FairWheel Bikes sells the Abbey ones too.

That's it for now, will come back to add stuff if necessary.

Just reading this as have a THM crank recently purchased and was told that a ceramic speed BB would be ok (BSA 30) now it obviously displayed some play some followed the instructions but when I remove the play with the adjusting screw then tighten the clamping screw at 10Nm the tighten the adjusting screw again at 8Nm the crank does not spin free and the spacers are set per instructions also. This is telling me I suppose that I really need the THM bottom bracket!

[Sanders2177]

Well had a repsonse from THM below

"Where did you get that statement from that the ceramic speed bottom bracket would work fine with the Clavicula crankset?
We can recommend our own BB’s only, they are specially made for our Clavicula crank. We have never test our cranks with BB systems from other manufactures.
Of course it it is possible that other bottom brackets would also fit, but in the most cases there will be small differences in the dimensions"

It's clear to me that a ceramic speed BSA30 does not work!
It will work if you remove the bearing covers but then as the bearings are recessed into the cups the cranks are very close to the BB cups and would
Likely touch under load like climbing hence how I discovered the problem due to noise and play going up Sa Colobra!!
So now forked out for a THM BB and the socket tool . And hopefully the sale of the ceramic speed would cover the THM bits. Lesson learned!!

[eucalyptus]

There is another thread somewhere on the forum concerning this where I have posted before.

I use BBinfinite BSA WS2 with thm clavicula se and it seems to work just fine right now.

Had it installed by LBS first with a 1mm spacer on NDS. Then had a small play.

Removed and installed myself, seems like it wasn't so hard that I first thought........ Removed the spacer and the axle + crank spindle interface lined up perfectly with the bearing. No spacers needed (of course bearing shields are still used). But it is dead spot on, so 1mm wider BB and it would not work.

Chainline seems fine too even though I have no spacers now and the THM is very different offset compared to sram cranks.

[Sanders2177]

There is another thread somewhere on the forum concerning this where I have posted before.

I use BBinfinite BSA WS2 with thm clavicula se and it seems to work just fine right now.

Had it installed by LBS first with a 1mm spacer on NDS. Then had a small play.

Removed and installed myself, seems like it wasn't so hard that I first thought........ Removed the spacer and the axle + crank spindle interface lined up perfectly with the bearing. No spacers needed (of course bearing shields are still used). But it is dead spot on, so 1mm wider BB and it would not work.

Chainline seems fine too even though I have no spacers now and the THM is very different offset compared to sram cranks.

Possibly luck when it comes to other bottom brackets. Considering how much the crank is I will stick with THM less hassle and if there are any warranty issue easier to resolve