masi61

So speaking from my experience using Shimano Hollowtech 2 cranks where the preload is set first then the pinch bolts are tightened. This work flow makes sense and is repeatable because the final tightening does not change the preload on the bearings.

What I am trying to comprehend better is more of the 30mm BB30 type of bottom bracket crank system. I have been playing around with Cannondale Hollowgram cranks with their splined 30mm axle in a non-standard setup. I put a 104/64 bcd spider on the cranks and am attempting to set up a triple crank with the 30mm axle and I want to tighten the Cannondale crank bolts to torque spec while maintaining the proper bearing preload and having no play. I have not made much progress in this area, yet.

But I can't effectively solve my dilemma unitl I understand what part of this crank/bb install happens in what order. Can I use wavy washers and different thickness of spacers then torque the arms to the torque spec and still not impair the smooth rolling of the bearings? Seems like this system is doomed to either damage the bearings or put too much side pressure on the bearings.

masi61

By the lack of responses I am again reminded that some of the mechanical problem solving dilemmas I get myself into are ones where I have to personally come up with solutions then report them back to my own thread for other people's benefit presumably. I found a few you tube videos where they were talking about swapping 30mm spindles between Race Face, Cannondale and some other brand.

If all I had to do was make sure that the crank arms were torqued to spec on the spindle, I would be stoked but these 30mm axle systems use wavy washers, pre-load adjusters, custom bolts etc... I know they are normally for BB30 bottom bracket bearings but in this instance I am trying to use BSA 30 threaded external bearing cups. I talked about it briefly in another thread and several respondents discouraged me or questioned "why?" would I want to do this. I really have not exhausted the number of things I will try in order to get this to work so I will keep thinking about this and trying out different length spindles and different spacer configurations.

Iride01 

I can't say for your hollowgram cranks. But essentially I think you just want to fully seat the crankarm on the spline. Or in other words, as far as it can possibly go! That way the distance between the crankarms will be the same every time. Depending on what your BB shell width is, you'll have some space to fill up with the spacers they give you. It really doesn't matter if the spacer touches the smaller diameter bearing race as it is turning at the speed of your crank when you pedal. But the spacers probably should not be so many that they prevent you from fully seating the crank arm or exert pressure on the inner bearing race pushing the two sides together. If you feel your chain line is off from what it should be, you can swap spacers to the other side if that will help. You don't have to put them exactly like they tell you to if you have a reason for moving them.

I have a old 2 piece road crankset made by RaceFace that was my first crankset that wasn't the old spindle, cups and loose bearings. It's similar in that it's crank arm didn't have pinch bolts like Shimano's HollowTech II crank arms do. And that's pretty much the procedure and things I presumed about how it all worked together.

You do have the installation instruction don't you? I'd guess the wave washer just goes on the non drive side. It probably just allows for BB shells that are a few fraction of a millimeter from spec to not cause you grief. And as well, to keep the drive side pulled snugly to where it should be so the chain line doesn't wobble back and forth from any space that might have happened due to things being a fraction of a mm from perfection.

FBinNY 

FWIW the right answer depends on the specific bearings.

Bearings fall into various categories, but bike use is most commonly a deep groove RADIAL contact type.

These do not want axial preload, since that forces the balls against the sides, and increases friction. The needed radial preload was built into the bearing as supplied.

So, your goal isn't preload, per se, but simply eliminating axial play, and no more. For these, it's better to err to the side of trace play rather than preload.

OTOH should the BB use angular contact bearings which work in pairs, then you want a preload comparable to that of classic cup/cone designs.

Russ Roth

Unless it has pinch bolts like a hollowtech it just gets tightened down all the way, spacers are used to get the tolerances close enough that the wave washer which can deform towards flat can take up the slight remaining gap without putting too much/any side strain on the bearings but eliminating play. In the whole thru-axle design, I suspect shimano's is the heavier design but definitely the better thought out and easier to set system. Dealt with this yesterday on a bb86/gxp install, pulling a crank 3x just to get a smooth spin is annoying.

masi61

By the time I get this custom Cannondale triple mated to this external bearing bottom bracket, I will have enough spare parts to start a new vintage parts bin containing "vintage Cannondale Hollowgram crank small parts". I have blown some spare money on wavy washers, Cannondale spacers, Enduro 30mm spacers and 30 mm splined spindles in lengths (109, 131, 132, now 119 and 124mm). I'm hoping that for my application the latest 2 spindles, one of them will give me the best chain line for my trekking triple crank and also permit full torque on the crank bolts with no play and still free spinning of the bearings.

veganbikes

The problem with people is they assume they should get an answer right away and sometimes that doesn't happen. From the timing I see it is about 3 hours difference between when you first posted and then you had a second post complaining in that short time during the day nobody responded. Patience is very helpful. Some threads are super popular and some threads can get missed or maybe someone doesn't have useful info.

In terms of using a BB30 crank in the wrong bottom bracket there probably isn't instructions for it because no crank manufacturers recommend using the completely incorrect bottom bracket with their cranks. BB30 and BSA30 while both having a letter and both numbers the same are different cranks for different bottom brackets with different spacings. Not sure why the want to use Cannondale cranks and modify them to be a triple and put them in the wrong B.B. they make triple cranks and they make the proper bottom brackets for them.

As others have said above if you are going to go for it make sure you don't crush your bearings.

masi61

Thanks for your reply. I did post that second post in a moment of temporary desperation on my day off when I was hoping to gain some insight from anyone familiar with 30mm bottoms brackets (BB30, BSA30 or otherwise). I actually have several really nice conventional triple cranks I can use for this project but since this bike is more of a project bike, I have been satisfied with marinating on non-approved solutions to see if I can come up with something that will work. The potential that I might crush the bearings will be the final deal breaker if the 124 or 119mm spindle cannot be made to work. I have not given up partly because to me I wanted to be able directly observe how a proper install of a Cannondale BB30 Hollowgram crank. I have a used Cannondale CAAD9 BB30 road frame that I could press the BB30 bearings into, then run the standard configuration of double road cranks. But for some odd reason, I plan to put an Enduro Torqtite BB30 24mm bottom bracket in that one to run Shimano cranks. Meanwhile, the Cannondale Silk Tour 800 that I have that has a threaded English bottom bracket, but for some odd reason I got it in my head that I could make this non-standard splined 30mm axle work with my Hollowgram crank arms with a 104/64 spider.

I will probably slowly advance this thread to give updates on how the 119 or the 124 spindle either didn't (or did) work out.