Hollowgram Spline Interfaces - Have they changed Si vs. SiSL vs. SiSL2

Need some help here.

Can anyone confirm whether the hollowgram crank:spider spline/interface has changed across various iterations of the crank?

For example. I have a quarq mated to a ratty set of hollowgrams, which from memory are SiSL. I'm in the mood to update, and go shorter as these will be transferred onto the TT bike, basically I want to know whether I can get away with buying (cheaper) Si cranks, or perhaps even (more expensive) SiSL2.

Thoughts?

The splines work. The spindles are different lengths. 104mm old versus 109mm SiSL2. As such the q-factors will be iffy. I have run SiSLs with a 109mm spindle. Felt a little more flexy and a tad weird. There's a handy chart/pdf on Cannondale.com that outlines what parts of which models are cross compatible.

The new spindle is 109mm simply to clear PF30 bb cups and support bb30a. The axle / arm interface hasn't changed.

With the correct spacers Sl arms should work fine on the new axle and sisl2 arms should work on the old axle.

The spider spline interface hasn't changed but CSG can confirm if you'd like to back up information on the Internet given by a stranger :)

RaceFace Cinch cranks use practically the same axle designs as Hollowgram, although neither Cannondale or RF officially acknowledge the cross-compatibility. Apparently SRAM XX1 30mm spindles also work.

WIP braindump:

RaceFace 30mm Cinch spindles (length is the number in the code plus 0.5mm):

For NextSL and Atlas:

• RF134
  
• RF143
  
• RF149
  
• RF169
  
• RF189
  
  

For SixC and Atlas:

• RF131BM
  
• RF136DH
  
• RF151DH
  
  

Q-factors:

• NextSL: spindle code +34mm
  
• Turbine: spindle code +44mm
  
• SixC: spindle code +39mm
  
• Atlas: spindle code +42mm
  
  

Chainline inset from end of axle:
RF Directmount (flipping adds 6.5mm to chainline), 3x 104mm spider & 1x 104mm DH spider

• NextSL & Turbine: 16.25mm
  
• SixC & Atlas: 17.25mm
  
• BMX 1x spider: subtract 3.5mm
  

Cannondale spindles:

• Si: road:104mm, mtn:132mm
  
• SiSL2 (extra 5mm driveside): road:109mm, mtn: 137mm
  
• SiSL2 on SuperX AI 2016+, PF30 x 83mm: 119mm for 1x, 125mm for 2x.
  
• Fat CAAD: KP402 160mm for 1x, KP403 166mm for 2x
  
  

Fat CAAD runs a 197mm thru axle, so probably a 75mm chainline. The crank is listed "Cannondale Si, BB30a, Fat Offset SpideRing, 30t", the shell "BB30XL 120mm" The back of the Fat-specific 30T SpideRing is engraved "30T CL71 BB shell DS 60 spacer 2.0"

Is there any way of finding out before hand what spacers I'll need to run the Si Cranks in with a RF 73mm spindle in a BSA BB?

Also we know if the RF drive side self extracting bolt will work with Hollowgrams?

Would be amazing if it does because you will no long need the cannondale tool to pull them!

"100mm" BSA shell, 160mm spindle, RaceFace BSA30 BB, Fat CAAD spacers, minus the bearing seals. No 0.5mm shims yet, need to work out how much the wave washer is meant to be compressed and whether the arms are centred, then find the spider that'll give me the chain line I want (less than the Fat CAAD's 71mm, probably about 65mm).

Pictured with the 5x110mm spider and a Surly 34t ring which apparently shouldn't be used with a 10 speed chain (larger sizes are thinner). Almost touching paint on the chainstay.

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Is there any way of finding out before hand what spacers I'll need to run the Si Cranks in with a RF 73mm spindle in a BSA BB?

Maths!

Cannondale publish PDFs listing the spacers required for various applications.

Scalpel PF30x73mm:
137mm spindle
DS: bearing shield (2mm?), 14mm spacer
NDS: bearing shield (2mm?), wave washer, 1-3 shims (0.5mm), 19mm spacer

So for BSA30x73mm, lose the bearing shields, make space for 10.5mm external cups:
134.5mm RF spindle (call it 134mm for calculations)
DS: 4mm spacer
NDS: wave, shims, 9mm spacer.

Your chainline will be ~1.5mm narrower than the same spider/ring on a Scalpel.

Great work thanks very much, now to find some where to get the spacers from...

Carbon-Ti X-Monoring 30t (round).

Comes with a black spacer that has the spline pattern on the ID, which goes on before the 'ring, and a metal (steel?) washer which goes on after the 'ring (fits into a recess in the inboard face of the 'ring). The washer ID was uncomfortably snug on the locking threads, kept getting stuck as I couldn't push it on without it going wonky. Ended up using the locking to push it on the rest of the way, since the locking always pushes straight.

About 5mm minimum clearance to the chainstay (normal to the paint, not parallel to the axis). Chainline is tricky to measure, but seems to be about 67-68mm.

Not sure whether the wavey washer is flat enough, haven't used any 0.5mm plastic shims yet.

When I'm sure the spacing is right, I'll pull the crank off again to clean and re-fit the locking and crank bolts with medium-strength threadlock and a torque wrench.

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am I correct in saying the 104mm spindle has a lip on it (drive and non drive side) vs the newer 109mm ones?

The 104mm spindle has a flange on one side. If there was a flange on both sides you wouldn't be able to slide the spindle through the bearing.

No flange on 109mm spindles.

yes I thought so, just confirming. thank you

Flange.

@Flange

Necro-bump to say I learned something new yesterday:

On Cannondale Hollowgram the arm aligns to one of the dips between the lobes on the spindle splines, both DS and NDS, so both sides are in-phase (the bumps align).

Sram, RF and Easton align the DS arm to a bump, so 22.5 degrees off from Hollowgram. Sram 30mm chainsets have the spindle "permanently" attached to the NDS arm, and although I can't find a photo of the RaceFace or Easton NDS separated from the spindle, RF sells spindles. RF spindles have both sides in-phase, so NDS must also be bump-aligned.

Most Stages power meters are sold as modified left arms, so either you send your left crank arm to Stages and they bond their strain gauge to the inner face and calibrate it, or they sell you a boxfresh arm with the gauge already attached, to match your crankset. For SRAM/FSA/RF/Easton, Stages sells its own carbon arm rather than adding their gauge to an OEM arm: https://stagescycling.com/en_gb/gen-3-stages-power-l-stages-carbon-power-meter-for-30mm-sram-race-face-next-sl-fsa-386evo

The Stages 30mm arm is dip-aligned, like Hollowgram, so the Stages 30mm spindles have the two ends out of phase with each other. https://stagescycling.com/en_gb/stages-30mm-spindles

If you used a Stages spindle with two Hollowgram arms, or two RF/Easton arms, you'd be cantering. If you used Stages or Hollowgram on one side and SRAM/RF/etc on the other side, the arms would be at 180 degrees like normal.