headrest install - trick? And: Seatstay holes not lining up

counterpoint

Well-Known Member
Is there a trick to the 2.0 headrest installation? My fingers are worn and so is my patience. The tolerance is so tiny, I can't get both rods into the second scissor jack. The first jack is already as loose as possible and still there seems to be a mm missing to get both rods into the halfmoon shaped opening.

Actually, it seems the lower one isn't even necessary.
scissorjack.jpg


Secondly: Unfortunately the holes in the carbon seat stays don't line up enough to allow for the male/female screws to fit through. Looks like I'll have to drill or file.
Any tips for drilling carbon?


seatstays2.jpg height:328px; width:615px

rearstay.jpg width:506px

 

Jeremy S

Dude
(1) Your picture appears to

(1) Your picture appears to show a bolt going through the small hole which I believe is an optional attachment point for the seat back. Are you trying to get that bolt through the headrest scissor clamp? Other than that bolt, I can't make out much in your photo. By "rods", do you mean the headrest posts? Are you trying to insert the clamps into the frame, and then insert the headrest into the frame? I believe that my one scissor clamp was held onto the headrest by a rubber band, and I inserted them both into the frame as a unit.

(2) I used a circular file to widen the holes by hand. First I inserted the carbon fiber piece into the metal piece (like you have), marked through the holes with a sharpie, then removed and filed.
 

counterpoint

Well-Known Member
The photo shows how the two

The photo shows how the two parallel headrest posts enter the top of the frame. They are held by the first /upper scissor clamp (its bolt is out of focus) and then go further in where they're supposed to be held by the second scissor clamp (silver).

The frame tube is closed at the top so the scissors can only be inserted throught he round holes. In this case both scissors were already inside.

I'll leave it as is.

2) Filing then. Tough material, I'm barely making a dent and have a full mm to shave off. Hopefully the other holes line up.
Not pleased. This is a key joint and we should not have to deal with widening holes that were designed to snugly enclose a m/f CS bolt.
 

iow

Active Member
if you leave the scissor jack

if you leave the scissor jack bolt heads as they are the seat will not fit flush with the contours of the frame. the whole scissor unit including the bolt needs to be mounted inside the frame - the force to expand the scissor is applied by the threaded end of the bolt pushing against the bottom of the frame tube, not by the head of the bolt pulling the scissor open as you currently have. also it appears from your photos that the scissor has been tightened too much and has gone over centre. consequently, tightening the bolt causes the scissor to close rather than open.

is your file sharp? a sharp file will take off a millimeter of carbon in a matter of seconds.

i agree, the poor quality control at the factory is bordering on unacceptable and does an otherwise excellent product no favours.

 

BBL

Member
Seat Stay to Rear Triangle Assembly

Counterpoint ....

If you haven't already filed your rear triangle, you may try tapping on the offending side of the rear triangle while blocking that side of the seat stay.

I had a similar experience while assembling my Silvio. The fit between the keys and keyways on my Silvio was tight. In fact it was a running (very light) press fit. The friction of the fit caused the seat stay legs to be sprung inward. So when one of the holes was perfectly in position, the other looked a lot like your photograph. It only takes a few thousandths of an inch for things not to fit. I was able to tap the hole into position using a rubber mallet. Of course you will need to be careful not to mess up the finish.

Although there was some considerable cursing before I was able to diagnose what was happening, I have come to appreciate the fact that these fits were designed tight. I did file the holes slightly with a fine file but only enough required to clear the flashing left from the manufacturing process. The fit between the hole and female adapter was very tight. The tighter this fit is, the more it approaches the structural properties of a rivet. This is important because this kind of a joint is far more secure (stiffer) than friction joint. The joints in my Silvio are as stiff as a bolted assembly could possibly be because the fits are as tight as they can possibly be. The down side is that it can be difficult to assemble, and one might mistakenly attribute this to quality issues.

Of course, not having seen the parts, I cannot say for sure that this is what's happening to you. I just wanted to tell you my experiences with what looks to be a similar assembly matter.
 

Ivan

Guru
+1 to BBL's suggestion for

+1 to BBL's suggestion for aligning stays and rear triangle. I did a lot of similar tapping and aligning to get my holes lined up. In the end I did not file anything. The joints are very tight so I had to use various methods, perhaps with less than the considerable cursing of BBL!

For the headrest, my 2.0 only has one scissor jack in the lower hole position of your picture. I installed mine in that hole. Mine had a larger bolt head, so like iow says, the seat initially did not sit flush. I did not reinstall my scissor jack inside the frame like iow did but elected to make a small recess in the seat back so it would be flush. I wanted the scissor jack in that hole since it seemed to be for that purpose. Since yours are factory installed like that and your holt heads are flatter than mine, I would keep yours in that position and not move it in the frame. Only one scissor jack is really needed, the second one is optional for you, so if you really don't like the second one then remove it. I would remove the top one as 2.0 does not have the top.
 

John Tolhurst

Zen MBB Master
The end of the HF tube is now

The end of the HF tube is now closed, and without a scissor jack positioned near there, it may develop a rattle. One will be needed in the middle for similar reasons. But as Ivan says, it can all be done with one.

The end of the HF tube is closed to allow greater weight to hung from the headrest.
 

BentBierz

Well-Known Member
DIY Solution for 2.0 Owners?

John...is there a DIY solution you would suggest for 2.0 riders? I am looking at several commuter bag options and want to make sure I don't overly stress the headrest but don't want to jump into any project that may have a detrimental effect to the HF tube. Thanks.
 

scabinetguy

Well-Known Member
Headrest install

I first removed the scissor jacks and installed the head rest with all 4 rubber sleeves then re-installed the scissor jacks.
 
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