# Special ring / 566 fork assembly



## Cooper1960 (Oct 14, 2010)

So I'm assembling my new bike and I have a question about one part. At the top of the fork stem is a spacer the book calls "special ring" It goes between the top of the stem and the bottom of the compression cap. I'm wondering if I was sent the wrong one with my bike because it just doesn't seem to fit correctly, or maybe I'm missing something. To me it seems like the compression cap should seat into the special ring and the ring should seat into the stem. Mine seems to large (leave it alone!) , it doesn't seat into the stem, the compression cap doesn't seat into the ring and it's not a decent fit on the pivot tube. My fork tube is 1.118 while the ring inside diameter is 1.177. 

I looked at the picture thread on this forum and didn't see the ring on any of the bikes but it's kind of hard to tell. Are people just not using them? Book says that's a no no. Can someone post a picture of there upper fork assembly and maybe I can see if I'm doing something wrong?

Thanks, Don


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## George M (Sep 25, 2008)

http://www.lookcycle.com/media/catalog/product/f/i/file_3_3.pdf


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## s30.hybrid (Oct 4, 2010)

The idea behind that ring is to assure the stem clamp is not pinched above the carbon steer tube ( referred to as the pivot tube in the Look manual ) to minimize the risk of damaging the carbon steer tube with the stem AND to ensure to headset top cap doesn't bottom out on the steer tube that is exposed above he stem clamp. It is basically a thin headset spacer placed above the stem and below the top cap. 

If you are assembling your new bike from the box you will probably need to trim down your steer tube to get proper fit for yourself. Most people leave plenty of spacers both above and below the stem clamp while getting fit dialed in. Once you trim the steer tube you can't add more length back if you don't like the fit. 

FWIW, I have seen plenty of people who dont use the small spacer above the stem and their bikes haven't exploded but it's a small little insurance piece to protect your new carbon fork so why not just install it. My bike did not come with it installed but I ended up adding a small spacer on top of the stem during my fit. 

Hope this helps and congrats on the new bike. What build did you end up getting?


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## Cooper1960 (Oct 14, 2010)

Thanks for the link George, and thanks for the info 30hybrid. 

I do have the manual but the picture just isn't definitive enough for me to tell if the special ring is correct or not. I know I have it in the right position but I just don't like the fit or the way it looks. I'm a machinist so yesterday afternoon I went to the shop and made my own ring, I just need to get down to the basement tonight and finish the assembly.

I ended up getting a 2010 w/Ultegra, Fulcrum 5 wheels. I ended up buying off e-bay because I couldn't get support for any local dealers. I posted here how the closest dealer didn't want to order one for me, I even gave him another chance and assured him it would be cash up front but he declined, he said he hadn't signed up with Look this year. The second dealer is two hours away, I drove all the way to his shop to talk with him about it. He didn't have a bike my size but said he could order it and would check pricing, I called two days later and asked him to get a price on just the frame as well and he said he would, but never called back. After a few days I sent him an e-mail asking if he had got the pricing and he never responded so I gave up. I always try and support local or smaller merchants but that philosophy needs to go both ways. I have to admit the e-bay purchase saved me some cash, $2190 and I didn't even have to pay shipping. The extra cash will let me upgrade to some better wheels and tires. 

I'm pretty excited, we have a big community ride to do next weekend and I'm keeping the new bike under wraps until then. I just hope I get a chance to get everything tuned by then, it's dark by the time I get home from work this time a year so all my test riding will be on the trainer in the basement.


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## scuollo (Aug 2, 2010)

*special ring - where does it go?*

I too am building a Look 566 - I had similar experience with LBS, I bought a used frame, called and said I wanted them to take a look at it, discuss components, etc. (the mechanic had worked miracles on my older steel frame setup for me). Maybe they were busy, but the response was "I won't make any money". I understand. But so much for having a "relationship" and willingness to pay retail. 

Anyway, My Look frame came with a FSA headset assembly. Included was a thin metal ring, the ID matches the OD of the steer tube. Is this the "special ring" called for in the Look schematic? The picture, however, looks like a cone shape, and I cannot see why they would want me to put an ugly bare metal washer under any top cap, especially a carbon one.

I saw some FSA diagrams, for other headset styles, that show a thin washer placed in top of the bearings and under the cover/cone. No diagrams can be found on the FSA website.

Anyone know about this?


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## Amfoto1 (Feb 16, 2010)

Hi,

The "special ring" is sometimes refered to in Look documents as a "specific ring". 

It's merely a metal (aluminum, anodized black) steerer stack spacer with a bit of taper to it, intended to go right under the compression cap. It's not very tight fitting and its purpose is so that when you tighten things up, the carbon fiber (CF) portion of the compression cap isn't gouged by the split in the stem that allows it to be clamped onto the steerer tube. 

The special ring will also serves if using a full carbon fiber stem, so that there isn't direct CF to CF contact. If that were allowed to happen, it's hard to get proper torque because CF drags heavily against another CF part. CF to CF contact is okay in compression, but not when you have to rotate a the parts against each other while under compression, the way you do when tightening the compression cap. 

Any standard aluminum headset spacer ring can be used instead of the "special ring". A standard spacer just isn't tapered, so doen't as neatly match the diameter of the compression cap. 

The thin spacers that stack on top of the bearing itself are different. Those are used _internally_ to adjust the stack height just right, so that the larger tapered spacer that goes onto the steerer right on top of the frame's head tube has enough clearance that there is no drag, but is close fitting enough that the rubber lip seal on the bottom of the tapered spacer can help keep dirt and water out of the head tube and the bearings inside it. 

When you are setting up the fork on the frame initially, these shims or thin spacers are the first fine tuning adjustment you need to make. You'll probably have to to approximate, assemble everything and use the compression cap to properly preload the head set bearings, check for drag or measure the gap, then disassemble to change the number of thin spacers to adjust it just right. 

If you are fitting a fork that hasn't had the steerer tube cut down yet, you might need to use a bunch of extra spacers on top to get things adjusted, then go back and take measurements carefully to accurately cut the steerer tube down to about 1 or 2mm shorter than the entire stack of bearings and spacers, so that the compression cap can put some preload onto the bearings. You can see this in the bottom illustration on page 21 of the pdf document referenced above. 

This illustration shows a standard integrated headset installation. There are some variances among Look models over the years: tapered steerer tubes, Headfit 2 and now Headfit 3 on the 695 (Headfit "1" is essentially just the integrated headset described above). .


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