Setting headset tension on a Lefty on a Fatty?
I have a Lefty with Mendon Cycle Smithís offset removable clamps and will be placing it on my On-One Fatty.
I assume that I add the appropriate number of headset spacers between the top of the headtube and the top clamp to remove most of the space and then add the stem above the top clamp and tension as usual. Once Iíve got the tension set properly this will remove any gap between the top of the headtube and the clamp.
In doing this I also need to make sure that the clamps still bind on the Lefty in the appropriate locations.
Is this correct, and are there any tricks for new players I should be aware of?
I recommend contacting Craig at Mendon. Can't recommend him enough, really a great guy to deal with, plus he knows his leftys and how to set them up properly.
I'm sure Craig will chime in here.
The only "trick" is to have the top clamp free to move along the Lefty body - and yes, it is good to make sure the clamps are on the "clamping" surfaces of the Lefty body. I set a 140 Lefty up on a Fatback w/o spacers between the headset and the clamps. This gives you max usable travel.
I recall setting up a bonded clamp carbon Lefty on a Niner RIP9 - which had a notably shorter headtube length than the bonded clamps were good for. That conversion used replacement steerer with spacers to fill the large holes where the CDale steerer was supposed to go. The bottom spacer was pressed, but the upper floated and had a slot so it would clamp to the steerer. This required using standard spacers between the top of the headset and the bottom of the upper conversion spacer.
To set tension on the headset, you left the upper clamp loose during the process. When you were done - hopefully the upper conversion spacer was still in position for the upper clamp. I recall having to reselect spacers to be fully happy with where the upper conversion spacer wound up - but once happy, clamp the Lefty and the stem.
For you - I would leave both clamps loose on the Lefty body until the headset is adjusted and the upper clamp tight on the steerer. I recall that you will need to align/center the wheel at that point, rotating the Lefty in the clamps 'til you're happy, then tighten the clamps on the Lefty body. Now you rotate the stem to center and tighten it down and you're done.
I look forward to seeing pics of the compete bike.
Fatbikes are much more fun than they should be allowed to be!
WSS/OSS: open source sealant
Wadester, thanks for the detailed advice. I also still need to build the wheel so it will be a couple of weeks before there are any pictures.
What Wadester said.