Clay has an article with pictures of how he did them on his site so you might want to look here:-
http://www.jclay.me/jclay/Triumph_TR-7.html#31
Clay is using a needle roller type which is quite thin. I got some similar ones from Robsport and I remember them being approx 4-5mm, their instructions are shown next.
However, there is another version that uses a ball bearing arrangement that is thicker and I measure them at about 10mm thick.
I have shown the bearing the "wrong" way up so you can see inside, it would be fitted the other way up.
Russ
1980 TR7 Sprint DHC, 1981 TR7 Sprint DHC
Dursley
UK
http://tr7russ.blogspot.co.uk/
[img]http://i1040.photobucket.com/albums/b410/dursleyman/TR7%20web%20picture/IMG_0479-Optimized.jpg[img]