I have a CAAD10 from 2015 that I bought used. I want to adjust the stem height on the steerer tube by changing the order of spacers/stem, before committing to cutting the steerer tube shorter.
I haven’t come across this type of round headset spacer before, google says they may be ‘splined’ spacers. Normally the spacers are all under the stem and the top cap sits directly on top of the stem. The diameter of the top cap and the stem matches well, i.e. the small flat outer lip of the top cap ‘sits properly’ on the stem and is fully supported all the way around.
In contrast, there are 3 raised splines on the inside face of the spacers and these are the only parts that contact the steerer tube as far as I can tell. Google says these may be ‘splined’ spacers. When sat between the conical headset cover and the stem, these spacers seem sufficiently supported by the surfaces they contact (top surface of headset cover and bottom surface of stem), but this doesn’t seem safe/appropriate for positioning a headset spacer above the stem to be held in place by the top cap - because the top cap OD is ‘too small’ and only contacts the raised internal splines (and actually, sometimes slips past them).
My initial feeling is that for any spacers that go above the stem, I should replace them with standard round spacers that have a smaller internal diameter that contacts the steerer tube the whole way around and have a sufficient thickness to support the top cap all the way around. Is this correct? Or, maybe I need a top cap with a slightly wider outer diameter?
For reference, steerer tube OD is standard 1 1/8". Can provide further details/pics if needed.
It is definitely odd, but Cannondale has done some odd things. I’d just use a traditional round spacer above the stem.
I guess technically, the Cannondale spline spacers are fine since really all they do is allow the headset bearings to be properly preloaded. Once the stem clamp bolts are torqued, the spacers theoretically wouldn’t be needed. That assumes that the stem clamp will never slip. Of course the theoretical world and the actual physical world are often not the same.
Does it look weird with top cap on top of that splined spacer? I wonder why Cannondale didn’t consider that someone would put a spacer on top?
That is odd. Can you think of any reason why they would have used these splined spacers rather than just normal round ones? Understanding the function of the splined shape might help. Surely any weight saving is trivial… On modern bikes, funny shaped spacers are commonly used to accommodate funny shaped steerers, or for aerodynamics, or for internal hose routing, but none of those would apply to a CAAD10.
I’m certainly inclined to say that if the top cap isn’t well supported by the spacers, then don’t use them under the top cap, and just use normal round spacers instead.
The other caveat is that when googling to see if I could find any more details, I did come across some people noting that some Cannondale bikes shouldn’t have many/any spacers under the top cap, in order to ensure that the stem clamp area is properly supported by the expander plug (to avoid crushing the steerer when you tighten the stem bolts). So worth checking whether or not that applies to your bike and proposed spacing.
Thanks both! The only reason i can think of for the splined spacers is to better match the outer diameter of the conical headset cover underneath the spacers, which to me seems a little wider than e.g. the top cap diameter.
Thanks for the reminder to check the original instructions for whether a spacer above is recommended/not. If allowed, I’ll probably swap them all out for standard round spacers (provided they sit properly on the conical headset cover)
I’ve had multiple CAAD10 frames and none of them have had these spacers. I have seen similar aftermarket ones though. I’d guess the previous owner put them on, but I could be wrong. That headset cap definitely did not come with the bike, so they made some changes from stock.
Other commentors are correct though - use a regular spacer above the stem with that cap.
The raised portions are possibly designed to ‘interlock’ to a degree, but otherwise these are mainly designed for light weight - not ‘splines’ so much as just reducing weight whilst still doing the job they’re intended to do.
Many many companies use similar “ribbed” or “relieved” spacers. They are supposed to be lighter for a given outer diameter. They are most likely original.
You technically can use the same spacers on top of the stem, but you’ll leave a path for sweat to pool and enter the steerer tube. It’s best to use solid spacers on top of the stem. That’s how Specialized does it.
For that generation of bike, Cannondale really didn’t want people running spacers above the stem. That said, considering how many stems have a large cutout in the steerer clamping area, and can leave the top edge of the steerer unsupported and ultimately damaged, it really is best to use a 2.5 or 5mm spacer above the stem no matter what. I wouldn’t leave more than 10mm above the stem though.
My SuperSix is from that time period. It had those exact spacers and the “no spacers above the stem” instructions.
I had constant headset loosening issues, as per me and several others who’ve called in to Geek Warning.
I would switch the spacers out for something more robust, and would strongly recommend switching the FSA expander plug out, if it’s still what you’re using. Longer, better expander plugs will allow you to put spacers on top of the stem as well
I ended up with a ring of death and now have a nice Enve fork.
I assumed they had the original expander until I looked more closely at the pictures. They seem to have a more conventional expander plug with separate top cap and bolt.
