Carbon Molded Threads, Crazy idea? | A Solution to a self inflicted Problem | REAMING

Bridge Cycle Works has produced a carbon fibre bottom bracket that has the unusual property of being completely molded. This video takes you through some of the quirks associated with the product and whether I think it will work or not.
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[@PeakTorque]

Couple questions for them i think: 1. Commercially how do they license it? When the Chinese factories know how, they will just adopt it in some bendy wendy IP dodging form and it will become their norm. 2. The case of demoulding warping between left and right BB sides is still a problem, surely? This isn't a problem when a shell is bonded in after demoulding the frame. For those ne connaissent pas with carbon fibre moulding, parts will often warp when taken out of a pre-preg mould due to captured stresses relaxing when moulding under heat and pressure. 3. Did they consider a short strand CF injected plastic for this? I would argue that might have better dimensional stability between left and right cups. 4. Pub quiz, can anyone name an interior thread that is rolled? 🎉

[@Hambini]

1. The problem with patents is having the commercial clout to be able to defend them. In only takes one little quirk and someone with lots of money and you are stuffed. 2. I don't think the two halves can be moulded that accurately even before adding the threads. 0.1mm is not a lot and then you have a compound stack up - I'd be amazed if they could achieve that. as you correctly say, the relaxation is difficult to account for. 3. That would be basically plastic?

[@PeakTorque]

5. Many companies can do a pf86 perfectly, with a cheap plastic shimano bb. I have 3 bikes with this and never changed a bb. Its hilarious how we are chasing such overcomplicated solutions. Even t47, doesn't need to exist.

[@PeakTorque]

​@@Hambiniregarding 3, yep, plastic. Many companies call it 'carbon' just because they lob in some short strand reinforcement. But it'd probably be plenty strong enough. Some performance yacht designs have been using CF injected PA for large threads for ages, at serious tensile loads. But considering the relatively low shear loads of human prawn power vs the actual huge size of a bb thread, maybe its doable. Difficult to bond to though.

[@Hambini]

@@PeakTorque The best standard I think is BB386 NOT EVO. it's essentially a BB30 made wider with two circips holding it in. SImple and effective, the wider stance means the misalignemnt problem is mitigated. This standard has never taken off though.

[@theillegalimmigrant9314]

Do either of you think this will be successful?

[@theillegalimmigrant9314]

"A solution to a self inflicted problem", you summed up the state of the industry in that line.

[@stfu6397]

Exactly

[@11robotics]

"Most people rejected his message. They hated him because he told them the truth."

[@JeanFrancoisDesrosiers]

Well, if you compare it to an alu threaded insert, he said it himself at 12:30 "it's still stronger bc you get rid of one interface" (the one between alu and carbon that is subject to fail, even just by thermal expensing/contraction). So, being a P.Eng myself, I think this is interesting, novel, and it may be progress if time proves it reliable.

[@michaelglidewell1524]

I think the best thing about this bike frame is that it got Luescher Teknik to make a video about it.

[@roadie3124]

I'm very happy to see that Raoul still around. I remember riding around the Hawthorn (Melbourne, Victoria, Australia) velodrome with him around 2000 or 2001. It might have been a little later. It's an open air velodrome, 3 laps to a Km and shallow banking, so most bikes are ordinary road bikes. He was on a home-built bike that was almost totally carbon fibre and was passionate about using CF as an engineering material, but he was also realistic about the problems ahead and didn't think that it was a magical solution for everything. From memory, his crank arms were CF, but his chain rings were aluminium. I have an engineering degree and had been interested in CF for many years, since the RB211 engine was first discussed, and had been close to the development of CF and other composites in building A-Class catamarans. He was a very nice, friendly guy who knew his stuff. I watched the video and I'm pleased to see that he's open to the idea but skeptical. He's also really good using the pen 😄

[@alexdi1367]

Future state for this: someone cross-threads a bottom bracket and destroys the threading. It can't be chased, so it's reamed out smooth, leaving a hole of non-standard dimensions. Then they reach out to you make a custom BSA insert.

[@KekusMagnus]

just as god intended

[@ThisTimeTheWorld]

Velo orange has internally threaded bbs that solve this

[@MrJx4000]

He's gonna take over the world.

[@AnttiBrax]

Hambini and Raoul Luescher reaming in unison. Beautiful.

[@richardhaselwood9478]

Raoul was his usual polite self. Hambini less so :)

[@leonschumann2361]

btw doesn't it seem weird how basically everywhere in engineering people just press some bearings in, yet the cycling industry seems to struggle with it?

[@dirkmohrmann8960]

Exactly, and the most bizzare part is that the cycling industry actually also does it successfully - the bearings are pressed into the bearing cups, which you then screw into the frame. Why they can't seem to make pressfit frames work, nobody seems to know

[@Surestick88]

But does every other industry fetishize carbon fiber like cycling does or would they just engineer the area the bearing is press fit into differently? I feel like most other industries would make an aluminium BB shell and bond that into the carbon.

[@artgreen6915]

​@@Surestick88 there seems to be very little information about this. But whether you press, you thread, or you bond an aluminium shell, does any of this deal with the differences in thermal expansion between carbon fibre (low) and aluminium (higher), and repeated temperature cycles? How does aerospace deal with metal to CFRP interfaces? Do they use aluminium for that? They certainly have to deal with significant temperature fluctuations.

[@apair4002]

Press the bearings on metal housing not into carbon housing/bottom shell.

[@simonm1447]

If you press a bearing into a machine made of aluminium or steel you have plenty of material and a CNC machined counterpart to the bearing. A bicycle bottom bracket is a thin, lightweight construction and both sides can be slightly misaligned too.

[@JamesPassmore]

I've personally molded a lot of carbon fiber threads in many different ways, when working for a company obsessed with trying to get that to work. It can work in static applications with light loads, provided the hole depth is a good 3-4 times the diameter. This, well, has me very skeptical. Invariably the resin seems to carry the load and the threads shear out under shock loading. The best case scenario we tested was cutting slightly undersize holes out of the carbon layup, so the fiber ends sort of frayed into the resin of the thread peaks. You can get passable but not great strength that way in a very thick panel (20mm thick carbon in my case), but nothing like the strength of a threaded insert. I can't see that style of layup being in any way used in a bike. I think, while they may have gotten it to work passably somehow, my guess is it would never be reliable enough for anything but a time-trial bike and it would never survive the first crash. I'd love a chance to saw one in half to see if they thought of something we didn't.

[@szurketaltos2693]

Maybe you can get your work to pay for two, one to cut up and one to "test"

[@JamesPassmore]

@@szurketaltos2693 Unfortunately, I don't work there anymore and I run my own business now, so work buying 2 is me buying 2😞

[@anthonybaxendale887]

What !!! I nearly spat my coffee out. Hambini " I lifted this from David Arthur" 🤣🤣🤣

[@mickf9149]

Good on ya, Hambini. I always leave your videos having learned something new, or rediscovering something I’ve forgotten.

[@DomH1994]

Hambini beaten to the punch by Raul Leuscher. Time for some soul searching.

[@Hambini]

hairdresser on tap (excuse the pun) for some happiness.

[@johnlesoudeur3653]

@@Hambini I hope that she is not tapping your BB lol.

[@MarrafaProjects]

I am connected to the Arts but I love cycling as it is my means of transport. Your detailed explanation is really insightful. Thanks! good stuff!

[@tychoMX]

Thanks for reviewing this! I concur with your assessment - it fixes a problem that shouldn't exist by relying on the same underlying root problem: the current production frames often don't comply with specs because of manufacturing issues derived from cost cutting. So doubling down and developing a thread system that relies on careful, diligent carbon moulding that accounts for shrinking, heat warping etc. seems like it's just asking for trouble even if all the material property issues (like fitting a metal bottom bracket with a sharp burr or edge on softer CF). It's really weird. I think you can make this work on a small batch/diligent manufacturing operation, but still is just one bad BB thread away from trouble. BTW - great summary on the engineering qualifications comment. I am Canadian and a P. Eng.; you described the qualifications well. And I don't know many people in the bike industry with the certification/denomination, either!

[@johnhrichak3451]

As a semi conscious crippled incontinent old ex racer geezer, I seem to recall I once owned an early Merlin Ti frame with a BB that featured the bearings located in the shell without any threads. I trained and raced on it, in all manner of weather, for close to 8 years before the bearings needed replacing. Sadly the design was proprietary and is lost to the past. Excellent video content from a 5 yo shitehead! Cheers

[@daniellarson3068]

I like that idea. If threads don't work do something else to hold it in. There's more than one way to skin a cat.

[@ThisTimeTheWorld]

​@@daniellarson3068 internally threaded "repair" bb for 68 mm shell. Two splined shimano bb tools install it. Done for years till it wears out. 35usd

[@adamweb]

As soon as I heard about carbon molded BBs last week I've been waiting for this Hambini video 😆

[@jdurkin227]

I didn't know about rolled threads, thanks for the lesson!

[@FiveMinuteVelo]

A great summary to my thoughts about this 'innovation'.

[@sirvince7853]

Brilliant video! I agree with your perceived problems with molded threads: Thermal Deviations, and layup Deviations effecting the alignment. Then ceramic coating the threads will eventually wear the aluminum bearing housing. Pivot Cycles has stayed with PF92 standard when other high end mountain bike manufacturers are migrating back to threaded BB. Having not owned a Pivot I can't say if they have figured out how to do press fit BB correctly.

[@thebikepackingadventurer]

The best solution to a great bb, but a Hambini bb, and never have an issue again 👌🏻

[@shepherdmyers]

I had Easton CX Fork once with internal threading, it was molded resin not CF. It worked very well over most expanding inserts.

[@vinnychoff]

A lot of learning given today. Thanks Hambini and those that commented.

[@tweed0929]

Hambini is onto something. Given all cost-cutting measures inflicted on mass production methods, someone had to "invent" that kludge. With aluminum BB cups there's still a threat of galvanic corrosion, but if the concept will prove itself viable (which I doubt it will), we'll see an avalanche of carbon fiber cups from every BB manufacturer rushing onto the market.

[@rollinrat4850]

I wrench at a Santa Cruz dealer for fun these days. I've never seen a single issue with a bonded aluminum bb shell on Santa Cruz' plastic bikes. I have friends who work there and I got a sneak peak at their frame torture testing devices. I was also the machinist at a NASA test engineering lab. I was also a mechanical inspector. Nobody's fooling me. I really like Santa Cruz as a company, but custom metal bikes have served me very well for over 40 years. I've been slowly restoring a 1977 Albert Eisentraut bike for the last year.

[@trentvlak]

I'll be monitoring the first adopters from the safety of my bunker. :)

[@mybrotherisnotapig6750]

I can't wait for samples to arrive and whether this actually stacks up to Italy's finest $7k handmade Bertolleti Legend!

[@terrycrowley8933]

I watched this video sea otter and straight away I said I know someone who is going to have something to say about it 😂 Great explanation thank you

[@simonlynch4204]

I saw the post on my IG... thought the exact same. 48h between seeing the post and the video. Top notch fact checking.

[@bobqzzi]

Good video. I love the nitty gritty technical details. You are a master at this It occurs to me that if no one ever tried to make a bottom bracket shell other than BSA68, bicycles would be just fine. The very best BB and crank design executed perfectly have such a minuscule effect on bike performance as to be effectively nothing for 99.9% of bike riders. Oh well, people have to do something with their time.

[@alexdi1367]

BSA is good for metal bikes. It isn't the best for carbon, neither the lightest, most efficient, or easiest to manufacture. That's why Cannondale introduced press-fit. "Fine" isn't the goal, best is.

[@bobqzzi]

@@alexdi1367 It works fine in carbon bikes if you use a metal sleeve- which is waaaay easier to manufacture correctly that anything else because most bike companies, including Cannondale can't manufacture the other types correctly. The totality of any performance advantage conveyed by less weight or more efficiency is effectively =0 when compared to the rest of the system of rider/bike

[@SethJayson]

@@bobqzzi They need a marketing hook, that's always the thing. If the system being sold is only suitable for a racer who gets a new bike handed to them every couple months, that's not an issue. Even a bodging idiot like me can glass-wrap a knurled aluminum bottom bracket shell and build a carbon bike on top of it that will never creak. But then I couldn't make the claims for an extra 6% stiffness to transmit my 85 watts to the pavement. The entire high-end cycling industry is more akin to Hermes than it is Honda. Expensive fashion meant to prove what you spent.

[@rollinrat4850]

Santa Cruz has used bonded/threaded alloy sleeves as long as they've produced carbon frames. Im a mechanic at a Santa Cruz dealer. Hundreds of them go through my stand every year. Ive never seen their BBs with any issue, besides those issues due to neglect. We only consider pressfit $hit to be job security! From a mechanic's POV, thats a great deal. Im also a retired machinist and mechanical inspector in several high reliability industries. Ive helped build carbon structures to the highest levels of quality on earth. Practically always, where high strength fasteners are required, a threaded metal insert or bung is bonded in. Given proper QC, its perfectly reliable. Given proper QC, interference fits could be used with good results. Unfortunately, QC is quite obviously a joke in the larger bike industry. The true definition of mechanical 'standard' is unknown simply because it would cut into profit.

[@markrushton1516]

wondered when you would be on this. At first I thought it was a bonded metal treaded insert but no. Love some of this custom work like those threaded inserts

[@sarahtoustra7127]

"Hello I'm beanie fans!" I love these YT auto-generated captions 😂

[@rollinrat4850]

I worked in a carbon only machine shop building satellite hardware. Wherever threads or bearings were required, a metal bung was bonded into the assembly. I'm no engineer, but this seems like a reasonable quality means of production to me. I was also a mechanical inspector. Now I'm retired, but wrench part time in a high end bike shop, part time for fun and various benefits. Nobody's fooling me and I generally see little to no QC on production bicycles. I see this as a serious joke. I'd love to see the process used to produce carbon threads. I know all about the interference fits found on the majority of most bikes. It's simply more job security for me!! In our shop, we were using more carbide and diamond cutting tools than I've ever seen in 30 years as a machinist. Producing carbon structures in a high quality manner was an extremely costly business. I'd be very wary buying a carbon frame that only costs $400 to produce in Asia. I might buy it from a custom builder whose hand I could shake, but I'm not willing to spend that much money on simple bicycles. $400 is about what a high end production frame costs to produce. I'll never buy one. My custom metal frames last indefinitely and the builders are my riding buddies.

[@simonm1447]

Typically metal inserts had been used in bottom brackets too. However they sometimes cause corrosion between the carbon fiber and the aluminium. If you make such things for satellites corrosion shouldn't be a problem since satellites are not used in corrosive environments and since they are outside the atmosphere there wouldn't even be a medium like oxygen which could cause any corrosion

[@rollinrat4850]

@@simonm1447 Santa Cruz has been using aluminum threaded sleeves in their carbon bikes for over a decade. Ive work at a Santa Cruz dealer for 7 years. I've ridden and serviced them for friends since Santa Cruz made it first bike in the '90s. I've never seen a single bb issue on a Santa Cruz besides wear and ignorance. Hundreds go thru my repair stand in a year. Santa Cruz is the only production bike I'd ever consider buying. I was also a mechanical inspector and machinist in my career. I saw Santa Cruz' torture test room. I was the machinist at a NASA test engineering lab. Nobody's fooling me! Quality control determines what you get. Sadly the production bike industry generally fails miserably at decent and responsible QC. I can prove it every day on most of our other brands. What the bike industry does best is marketing BS. They're excellent at pulling the wool over unknowing consumers eyes and taking their money. Then, they rely on retailer shops to take the heat and solve the manufacturer's problems caused by their own greedy compromise and incompetence. I've machined carbon aerospace hardware as well. We always bonded in metal bungs where threads or bearings were required. This is reliable enough (in a QA controlled manufacturing environment) to allow satellites to function in space for decades. I'm still riding US made custom frames after decades of hard use. I'm restoring a custom bike made in the '70s. Bearing tolerances and threaded interfaces require machining. That's what frame taps, facing tools and reamers are all about. Ironically, you cannot often use these tools on plastic bikes, nor correct frame alignment by cold setting. These tools make threads, interfaces and interference fits more accurate after frame construction or heat distortion from welding. Frame alignment is a no brainer! You don't need a million dollar machine shop. I've taught teenagers to use these tools. Any decent shop has these old school tools. High quality in the production bike industry has become the exception rather than the rule. Cheap yet waaay overpriced junk should never be acceptable where human life relies on the hardware.

[@johnbeckmeyer1696]

At the end of the video, you suggest that bike manufacturers make the bb hole smaller than needed and then bore it out. Earlier in the video you explain that cut carbon fiber tends to fray. I think the problem remains to be solved. 🤔

[@ianiscaratti4924]

if I remember correct schmolke already did m5 carbon screws for bottlecages and they pointed out that the fiber is layed in to the thread and its not a thread cut out of a carbon bar or even some carbon powder mixed in to a special screw plastic.

[@ajmeyer66]

I would think it should be easier to create a dimensionally stable bore for a good interferance fit for a press fit bearing rather than creating a thread and then threading in a cup to in turn hold the bearing. Seems like a lot of over engineering to solve an issue that shouldn't be there if the hole was just created properly to begin with. I think a better solution would be to mold in a bottom bracket shell machined to allow for a proper interference fit and just press fit the bearing into the shell that is molded into the frame.

[@truantray]

That solution sounds much easier than it is. But if we're going to mold in alloy bits at critical parts of the frame , why not just the radical idea of making alloy frames?

[@shus5787]

Been waiting, u took ur time

[@Hambini]

That's what she said.

[@Hambini]

@@bigstu_ Maybe Roaul is my hairdresser, now that would be a turn up!

[@cypriano8763]

genius, lets make the threads even easier to strip. bravo

[@buning_sensations5437]

Next, threads made with dried play dough.

[@nobrakes7247]

Thanks mate

[@GNX157]

My 1987 Buick Grand National V-6 turbo engine had a rolled fillet crankshaft for extra strength.

[@cfgosnell]

With regards to the threads, I wouldn't necessarily say 'stronger' although some cold working may increase the tensile strength of the material slightly. More importantly the the fatigue crack resistance and grain refinement of the rolled threads. They could also be 'smoother' and 'burnished'. I'm wondering if it would be better to make threads with some type of partial clearance or even missing thread portions that needs to be filled in with some type of sealant. Then use the threads for concentricity and gross fitup only and use the flange faces for alignment/perpendicularity, etc... Or just use a one piece bearing assembly? Kind of a solution looking for a problem...

[@ColinWatters]

Several papers have been published on moulding internal threads in composite tubes. They suggest it can work.

[@wss327]

The clip showing Ceramicspeed BB screwing in is maybe from David Arthur at Sea Otter?

[@maniastrat]

Wow these new fan-dangled carbon bikes have almost caught up with steel & aluminum bikes now with threaded BB's without needing a insert🤣😂😛

[@mikeh.9843]

endless humorless story. Learned a lot about misalignments on this channel, as I am an old school engineer just horrified riding a Bianchi: uphill the creaking is so loud that even walkers turn around. will send my CF-frame to Manchester when end of life is coming...

[@bstokes297]

Another bike that is going to do this is the Lemond 8, and high end racing frame that claims to use no metal pieces in their final design, including bottle cage bolts or brake mounds.

[@leeharding8306]

I watched the video where the guy is spinning the bottom bracket into the frame section. The thread looked quite baggy by the way he spun it in. I’ve owned frames where the aluminium bb shells have corroded in the frame and killed the frame so this is a clever idea if it works.

[@edmundhodgson2572]

agree with the last comment ( the one before the hairdresser) about just boring a hole as part of the finishing procedure, but, as you mentioned earlier, wouldn't this lead to fraying of the fibers from doing this?

[@markb9571]

I'm sure someone could get the first ply down fairly well consolidated with a plain weave, but assume the 2nd ply would have to be bootlace crammed in and it would take a skilled aerospace/f1 laminator bloody ages to push the material in properly. In mass manufacture the peaks would probably just be bridged and resin rich. You can see the voids on some of their pics of what you assume is one of their better attempts. Maybe chopped strand/resin infusion would work better. I'd love to see a close up of the threads, and the layup, really interesting project! Although for a bike I'll have my bearings and threads into metal please. Seems like a great way for peak torque to make some lockrings for his 180mm discs 🤣

[@SethJayson]

Tight angles with CF never work well in my (very limited) experience, and I think they would be nearly impossible to make in the way that would make strong threads, if my understanding isn't wrong. The fiber layup I presume you'd need (zigzagging up and down the thread profile viewed in cross section) to take up the forces pushing against threads perpendicular to the BB axis could never be turned by any CF fabric I've seen, which is why their explainer seems to indicate they're just wrapping uni tow around their molds. But that would mean thread peaks and valleys were primarily resin unless they could somehow jam smaller bunches of individual fibers into that zigzag profile? And in the end your thread strength would still just be the resin holding the bundles together?

[@iMadrid11]

Who knew the bike industry quest to save weight. Shifting to Carbon Fiber-Reinforced Polymers would introduce a new set of problems. Any new material will of course introduce a host of new problems that previously doesn’t exists. Because we are still learning about that materials strength and weaknesses for a specific application on bike frames through time. The first carbon fiber bike with aluminum lugs was raced by Greg LeMond at the Tour de France in 1989. We are just on it 34th year of real world application in 2023. We are still a long way before carbon fiber bike frames would be as solid and trouble free. When compared to steel, aluminum and titanium bike frames.

[@philoso377]

What we need is the spindle axial aligned perfectly and that thread molding is OK but necessary. What we need a mold specific alignment-insert-BB to be threaded into the production BB-shell then apply CF. Essentially that is equally good alignment as the molded thread. We are running the risk that the production tool thread former will be permanently bonded with the production shell. We still don’t know the structural relation between the thread and the frame. Why didn’t they went all the way through molding the thread into ACME profile? Given the CF grain direction, a small axial impulse, bump, can be a significant destructive force to break the thread profile away from its root.

[@fcktherich6913]

I'd bet they wrap long fiber strands around a threaded die and do the regular curing process from there. At the stated fiber size they would be able to fill each thread with a couple widths. And you wouldn't have to cut the carbon after you've formed and cured it.

[@panchoxbrr301]

This is a fine blend of Hogwash & Snake-oil, shaken not stirred. Steel BSA FTW !

[@dmlopezleon]

buen video, que opinión tiene sobre los soportes BBinfinite? Para mi opinión el mejor es el T4786 y después el pressfit BB86,(ene carbono). Si los insertos los hicieran en titanio se acabaría el problema que tiene el aluminio con la corrosión

[@StanEby1]

Brilliant as always and very educational, but the proof is in the pudding. Perhaps they have come up with an isotropic remedy and/or a newly improved substance. All the best.

[@seanrequiredfieldcannotbel1362]

If the alignment is "perfect" then why cut threads into the frame? Use your "perfect" alignment and have your rider press fit their bearings in. The simple solution was long ago made by Cannonade. It's just that manufacturers can't do "perfect" alignment.

[@Hambini]

totally correct.

[@anotheremailaddress9664]

It’s more that it’s too expensive to manufacture perfect alignment. They would rather lower cost and make most of them “good enough.”

[@seanrequiredfieldcannotbel1362]

@@anotheremailaddress9664 then how does aligning it perfectly and cutting threads into it improve... anything?

[@anotheremailaddress9664]

@@seanrequiredfieldcannotbel1362 I’m not arguing it does. While a threaded 100% carbon bottom bracket shell is impressive, it’s not something a Giant or Merida would rush to do.

[@kirynkokos5751]

HALLO!!!!!! Hambini!!!!

[@SethJayson]

Most manufacturers can't align a pair of smooth CF cylinders perfectly, but threaded cylinders will be? IMO (ham-fisted home wrench and bikemaker) aluminum is already sometimes tricky enough as a threaded BB shell a regular person. I've had to resort to some crazy gymnastics to free up and reinstall BBs in improperly-prepared and maintained BBs in aluminum, and it's always a treat know that if you can't chase those threads clean and aligned *very carefully* the frame will be junked. (amateur tip: an old steel BB shell with shallow grooves cut perpendicular to the thread with a rotary tool makes a decent DIY chasing tool.) Isn't the force on these threads perpendicular to the direction of the CF? (on axis with the bb spindle?) Wouldn't that mean it relies on the strength and stiffness of the resin alone in resisting any outboard, inboard push-pull? Does pedaling generate those kinds of forces?

[@event4216]

Hambini, what's your take on track (or SS, if you like) hubs with hex bolt axles? To me it seems OK for front wheel but rear is sketchy. I have seen a hub hex bolt axles which has no serrated surfaces compressing against dropout - I've been offered such hubs but it seems too boutique for daily use. Probably I'm just too cautious but my background from working as a machinist sniffs a catch there.

[@PeterPutz82]

Great video thanks Hambini. PF30 is fine, works well is light. We all know the industry has failed. The accounting department drove the decisions and pushed for cheap manufacturing. Tolerances couldn't be achieved so the marketing department stepped up to cover up the mess and have also failed. I flatly refuse to go back to threaded anything and as a 70kg rider, rimbrake works great for me. With interest rates skyrocketing the second hand bike market is alive with high end bikes. Interestingly a precovid S-works DuraAce SL6 goes for aud$7000 where a post covid SL7 goes for aud$14500. If I'm buying a bike, I'll grab that SL6 with pressfit, rimbrake, 6.4kg for half the price of the disc brake, threaded, 8kg SL7 any day of the week. The bike industry is screwed and you only have yourselves to blame.

[@galenkehler]

5:35 rattling good fit 👌 am I way off in thinking that is a really slack fit on the demo unit? Ive never had a BB that loose going in before.

[@Hambini]

That's the radial clearance. it suggests they are either slack or very well machined/low friction.

[@MultiSigil]

Yay shutout to the Chartered Engineers 😃. Chartered Civil Engineer here so going so will sit quietly and listen to the mechanical engineering talk 😅

[@hmartinlb]

Is the reason that no one machines the pressfit holes / bearing seats in carbon that the tools get dull / destroyed too quickly?

[@glennoc8585]

I wonder if the ceramic coating they use is a two part coating. You'd want to get the coating at a few microns. This seems very novel and F1 but not for long term use.

[@truantray]

The last time two engineers got together in Toronto, we got Cervelo.

[@dcv9460]

Interesting 🧐

[@bbqreunie984]

Interesting stuff. I am quite curious how this is going to develop. But basically it's indeed a failure of the bike industry unable to produce it in another, better, way.

[@tobiaslee866]

@Hambini Rumor has it the new Time Alpe d'Huez has carbon thru axle dropouts. I'm curious if the same concerns would apply there. Thanks!

[@TheBarnaby25]

Well said Hambini. Essentially just another over-complicated development... instead of just doing it right in the first place.

[@winstonmatthews6815]

Good insights, and yes the freaking industry is letting down the consumer. Their one and only true goal: massive margins from the cheap as possible bikes they make.

[@darojos]

Unrelated to this post. Do you think Enduro's "BKSM-8142 - Maxhit, 440C stainless steel, BSA30 Bottom Bracket kit" addresses the issues related to 30mm spindle in a BSA BB?

[@dirkhunt9425]

Press bearings directly into the frame? Like BB30 without the BB?

[@artgreen6915]

Hambini, is your long held position restated here at 16:37 not at all contradicted by the point you make at 6:37?

[@bantolphbantir9605]

In this light, could you discuss "forged carbon" like Time uses in the ADHX. Those are the two things that sort of scare with that frame, especially in terms of durability. I asked Time a few questions about these, such as if I should use grease, threadlock, leave them bare and if I should limit use to a single set of Thru axels and never got a response. What happens if some dirt or foreign material gets in the threads?

[@user-xg2fj5uc2g]

There is no threads in carbon on the ADHX, it is in an AL-insert (fork) or hanger (rear)

[@bantolphbantir9605]

​@@user-xg2fj5uc2gThis is incorrect. The Frame Specs on the Time website clearly say the dropouts are forged carbon, and if I inspect the ADHX frame and fork sitting in my garage - it has threaded carbon for the Thru axles. There are no inserts. The only Al is the derailleur hanger.

[@thinkingcashew6]

Seems interesting, I'm not convinced that this is really the right application for this. If they can do this all in one step with minimal part finishing I could see this being a decent improvement over a traditional bottom bracket. Also when you fck up your bottom bracket threads they can sell you a whole new frame! Apple level innovation in bike manufacturing is not what I was expecting in 2023.

[@dosgos]

Bike industry relies on evolving "standards" and "technologies" to sell new parts & new bikes. The audiophile industry also does this well.

[@louwn]

Bro if they can figure out and make treads in a carbon frame why is a simple press fit BB to hard to keep in spec?

[@jptrainor]

In canada you get a p.eng by completing a bachelor's degree at an accredited university, registering with the provincial engineering professional body and getting four years of work experience. For a long time it was only two years. There's an ethical exam but there's here's no technical exam. Not a terribly high bar, but thats just IMO.

[@truantray]

Didn't Trek switch to carbon machined bearing races in the head tube at some point?

[@Surestick88]

A side note, as a Canadian, when someone says their product is made in Canada it's not "proudly made in North America" it's made in _Canada_. We are not "Americans". There's a bit of history there.

[@KingJames6306]

The problem is we've moved on from metal frames while trying to still hold on to manufacturing features/processes from them.

[@therainbowgulag.]

The problem is with the frame manufacturers. If they could make a round hole we'd all be using preff fit. I don't see this as a solution except for boutique brands.

[@communist-hippie]

One question. Why cant the manufacturers after molding a frame. Just bore both bb holes to exackt dimensions? And the meantime line them up?

[@bowlander]

My bottom bracket is making a creaking noise! Bridge: Hold my beer.

[@hockeyiscanada]

What, Time bikes are moving their braided carbon frame production to Canada ?

[@letheal]

My initial intuition was that using the fine threads that work in aluminum and steel probably isn't right for carbon. It doesn't seem like carbon could handle the shear strength and the threads would crack off instead of deforming.

[@KekusMagnus]

Just imagine cross-threading that

[@buning_sensations5437]

Hum, wondering if Delta Tech near Lucca Italy is working on this. Just because you can - doesn't mean you should

[@MrAnon-2024]

When I first heard this I had to check it wasn’t April Fools Day!

[@philoso377]

Press fit precision is dictated by how square the pressing surface is to the pressing axis?

[@spishco]

P-Eng in Canada is "Professional Engineer", like the USA.

[@naf2579]

My steel gravel bike is 7.5kg, the stainless T47 BB shell has great alignment, and no signs of corrosion. The bike industry creating solutions for problems that don't exist.

[@shoeboy23john89]

I agree, I didn't relise I had a problem with my BB in all my years of cycling. The cycling industry is unbelievable in coming up with BS.

[@simonm1447]

How can a steel gravel bike have 7,5 kg? Does it have carbon wheels etc? I have build up a couple of bikes, the frame of a trekking bike (OK, a little bit heavier than a gravel bike frame) has between 2 kg (Aluminium) to 2,5 kg (older cromoly steel frames), so even old steel frames are just a fraction of the total weight. The rest adds up the weight, to build a really lightweight bike every other component has to be lightweight too. If you use the inexpensive standard components with Aluminium wheels you end at around 12 to 13 kg, and a carbon frame alone would save 1,5 kg at max without weight savings on the other components

[@naf2579]

@@simonm1447 English cycles knows how to build a light weight frame, lightweight yet proven durable components, carbon clinchers, 38c tires, full mechanical 2x red 22, stages power, growtac mechanical disc brakes.

[@devdroid9606]

@@simonm1447 look up the Yasujiro Svelte. 5.5kg.

[@seanmelvin5115]

Hello all. Figured this might be the best place to find an answer. I have a bike with an M48 BB and I would like to replace it with a shimano xt. To do this I’m guessing I would need some type of thread in “side down” has anyone seen something like that? Or have other options? Thank you for your thoughts, time & help

[@larryt.atcycleitalia5786]

They bust their ass figuring out how to make everything cheaper. Better for you? Not likely. More profitable for them - CERTAINLY! When the threads strip out Hambini to the rescue!

[@gokaygs]

So is BB30 the best BB design then with bearings being in frame and no interface??

[@MrHoward222]

Hmm, I bought a high end (full DuraAce 7800) Trek Madone in ca. 2008. It was equipped with the then newfangled BB90 (direct pressfit) bb. I’ve still got the bike and enjoy riding it BUT I’m on my fourth frame and forks. Trek have replaced them 3 times under warranty due to bb issues. I’ll say one thing, they stand by their warranty!

[@savagepro9060]

Hambini: "A Solution to a self inflicted Problem" Carbon Threads: "Screw You! . . . in essence"

[@volvo245]

Traditional threads in plastic parts are dimensionally and geometrically very different from ones used in metals. Trying to make very fine threads work with CFRP seems insane for consumer products.

[@saltycycling]

Nice! Just watched a video from Luescher Teknik about this, and was wondering if my second-favourite cycling youtuber will resist the urge to comment ;-) It's almost impressive how their website manages to squeeze in so much BS in 4 simple paragraphs, isn't it? Basically acting as if press-fit didn't exist and comparing everything to 'traditional' threaded. If they only took all of the effort and resources they've spent on this 'pretend innovation' and marketing to improve their manufacturing, who knows what could happen? Maybe they'd actually figured out how to produce press-fit properly ;-)

[@u.e.u.e.]

Shouldn't the CF layout be better 90° from your 1st sketch to absorb the shearing forces better? 🤔 But how could they provide enough pressure from inside during the epoxy curing process to bend the carbon fibre and not having any voids in the thread? 🤷‍♂️

[@blownouttransmission5832]

i would have to question the long term ductile stress resistance of the epoxy , while initial fitting may achieve a suitable torque level , the epoxy may be in a ductile state that moves very slowly and thus failure may occur after a year or so of repetitive torsional loads being applied , also the threads on the cups will have to be formed just as accurately as the bb shell thread . i do not believe such tolerances are available to any mass production or even bespoke builds as the rejection rate before a truly usable interface is achieved would be astronomical . the video of the bb cup being screwed in demonstrates the slop in that joint , even my low power string arms could strip those threads in a heartbeat , even with successful initial fit , a strong cyclist would be by the roadside cranks flopping around after a mile .

[@leonschumann2361]

hambini bikes, build/molded around bottom brackets when?

[@christopheroliver148]

Sounds like the A10 Warthog. Here's a big f'in gun; build a plane around it. ;-)

[@defenderoftheadverb]

Maybe they use nano fibres for isotropic strength.

[@the.communist]

I guess innovation is where the money lays

[@budbarlang3729]

like hambini said make the holes smaller then bore it out it will be perfect every time ,why don't the bike industrial do that?