shoota 

So let me run this by you guys. One picture is a shimano hollowtech crank in a threaded bb. Notice how the spindle nearly reaches the beginning of the other crank arm’s splines. Then check out the other shimano crank in my Warbird. The spindle doesn’t reach nearly as far into the crank arm. I feel like this isn’t right. I’m not using using spacers so I can’t take any out. What do you guys think?

Andrew R Stewart 

Sorry but I don't discern much of anything from the photos. Is there an actual problem or are you just nervous? Andy

DOS

Warbird is BB86?

shoota 

Well, the difference is noticeable in real life. The pics aren't bad if you know what you're looking at. I'm trying to discern if there is a problem, I have suspicions.

I believe so, yes. Which in theory should be just fine for Hollowtech cranks.

DOS

It does look like the spindle is coming up a MM or two shorter on the BB86 one. Check to make sure cups are fully pressed in. Then, before tightening the pinch bolts, dial down the preload cap (just hand tight) then pull it back out to see if that helps take up the space.

shoota 

Did that already. The crank arms are both right up against the bb shell/cups. There's no way to move them any closer together. They way I see is that the spindle needs to be longer...

My worry is that the outside pinch bolt on the NDS arm is basically not clamping down on the spindle, it's clamping onto nothing. I lost a Dura Ace Stages crank arm the other day due to splitting around that area of the crank arm and I'm wondering if this is the reason why...

masi61

How many mm short of the end of the crank arm is the spindle coming? Can you take a picture of the outside of it?

AnkleWork

Does the safety pin engage the hole in the spindle?

tomtomtom123

BSA Shimano Road BB cups are 11.5mm thick, while MTB BB cups are 10.5mm thick. On Road 68mm shell, if you add 2x11.5mm road cups = 91mm total BB width. For 2x10.5mm MTB cups on a 68mm shell, you're supposed to add 7.5mm of spacers = 68+7.5+2x10.5= 96.5mm total BB width. Pressed or threaded BB for Shimano MTB should still have the same total width (so they can run the same cranks).

Are the 2 photos on the same bike with 2 different spindles, or are those 2 different bikes with 2 different spindles?

If it's the same bike and 2 different spindles, then maybe one spindle is meant for road and the other is for MTB.
If it's 2 different bikes with 2 different spindles that have the same spindle lengths, then the total BB width of the 2 bikes do not match. If these are MTB, then you should check if they're a total of 96.5mm.

Also, there was a blog somewhere that you can find on Google, if you search shortening shimano hollowtech q-factor, where the guy said that his old Shimano MTB spindle had enough tolerance to remove 1 of the 2.5mm spacers from the BB cup. He then said if he cut off some of the splines in the left arm, he could remove another 2.5mm spacer without the spindle sticking out of the left crank and without the splines bottoming out (after cutting some of the splines). So I assume some Shimano MTB cranks you'd see at least 5mm gap between the end of the spindle and the end of the crank splines.

shoota 

Nope.

AnkleWork

Then the shell is too wide, or the cups are not fully seated, or something else is wrong.

Have you measured the shell?

shoota 

No, I just assumed it was 86.5mm since that's what it's supposed to be. It's an easy thing to measure though so I'll do it. I've watched a couple videos on youtube and several of those people didn't have the pin down either. If this is an issue I'm surprised I've not come across it before.

tomtomtom123

The overall BB width from dust cap to dust cap is what's most important, because it determines how far the spindle will insert into the left crank arm. I mentioned previously that Shimano MTB BB are 96.5mm wide, while Shimano road BB are 91mm wide.

This site claims that Shimano MTB BB is 96mm, but I think it's closer to 96.5mm because of what I mentioned with the cup width being 1mm thinner on each side than the road, and the 7.5mm spacers that comes with MTB BB cups for 68mm shell, therefore the MTB being 5.5mm wider than the 91mm road BB.
https://wheelsmfg.com/bb-overall-widths

The site also claims BB86 for Shimano to be 92mm, and BB92 for Shimano to be 97.5mm, but usually the manual or the exploded diagram will show some spacers to get it as close as possible to the standard Shimano MTB BB of 96.5mm, otherwise you won't get the same chainline and spline engagement when you use the same MTB crank on all these different BB systems. But +/- 2mm probably won't make much difference.

shoota 

Ah ok I see what you’re saying. Let me go measure that. Thx.