Park tool says to go to small ring, large cog and get 1mm of space between the derailer and chain. Shimano says to do the same, without cable tension set, and make the limit between 0-.5mm. Problem with Shimano is that when you put tension on, it closes the space up. What is a good place to set that low limit so A) the chain does not fall off on shifts, and B) you don't get rub in the low-low position.

If tension is pulling your FD into the chain, then the problem is that your tension is set too high. The screw is just a stop the RD pivot hits. If it is pulled away from the stop, then the screw has zero effect, and is not what is causing your problem.

Limit screws are exactly that - limits. The do not replace correct tension.

What I do with the FD is set the lower limit without cable tension (make sure you're in the lowest gear in the back too). Then I tighten the cable until I physically see the FD move, then go back a half turn. That way the tension won't affect the lower limit, and you'll have enough cable tension to smoothly shift into the big ring.

Since I've done this a lot, I can kind of just feel with my hand how tight the cable is, and when it's too tight or slack.

One other question: With the REAR DERAILER low limit screw. I am trying to figure how to get the best setting without throwing the chain into the spokes. How much leway do you have with loosening the L screw once the chain shifts to the biggest cog? What I am saying is, let's say the chain shifts up to the big cog, how many more turns of that screw will make it jump to the spokes? I just want to know so that when I fine tune, I will not go to far. I have read park and shimano. The problem is the teeth on the cogs are not perfectly straight, so if I line the pulleys up with one tooth on the cog, it may be too far in on some teeth of the biggest cog, just right on others and too far out on others yet......

Technically, the large cog limit screw is also just a protection device. If the cable tension is set right, it's not even needed. The shifter should never try to go beyond the large cog and into the spokes, unless the cable tension is too high. Shifter design can play a part in whether the screw has much effect. Some shifters may not have quite as positive a stop as others. I've found that I never need the large cog limit screw with Campy 11.

That is good information DaveSSS. For ****s and giggles, wif you were to set the low limit screw. Whould you quit loosening it as soon as you were able to get a good shift from the second largest, to largest rear sprocket, or line up the pully and large sprocket at the limit. Shimano claims to line the pully and larges cog perfectly, while Park says to set the screw the tightest you can, and still get a good positive shift. Mine is at Parks recommendation right now because in my limited knowledge, it seems like a safer bet. But I will change this, if my suspicion is wrong......

How much travel you get out of the RD also depends on the relationship of the cassette to the derailleur hanger. Some frames have a hanger that's so thick that a spacer is needed behind the cassette, just to get the cogs far enough to the right. Campy recommends 7-9mm from the face of the axle. I recently put a .75mm spacer behind the 11 speed cassette on a powertap wheel because the RD would barely travel far enough to the left.

This is what I have. I can adjust the low limit as per park, or Shimano without any spacers. I can have the adjustment so that the derailer stops as soon as it shifts to the big cog as per Park. Or I can even set it a bit looser as per Shimano involving no extra spacers. Which way is preferred. The Shimano way brings the derailer closer to the spokes, but at what cost, rather than have it set like park tool? My question really is what is preferred if you can set it either way??

Shimano includes a spacer to be used with 10 speed cassettes. Other cassettes don't normally need spacers. Not enough info to comment further. As long as you get enough travel and don't hit the spokes, it doesn't matter.

So stop adjusting towards the spokes as soon as I get the last upshift?