So lets say I'm leading a single pitch sport climb weighing in at around 175lbs... My belayer is around 120lbs.

Do you recommend the belayer tying in to something on the ground (No Fall Hazard for belayer) or not tying in and being pulled up...

Is this just a personal preference thing or are there things to consider. If so what are the considerations??

Good on ya

Junior

It depends on the ground conditions, of course, but in most circumstances, I wouldn't anchor myself to belay a sport climb, even if the climber outweighed me like you're describing. The belayer probably won't get pulled up much if any unless you fall before you clip the second bolt. You'll get a softer catch if the belayer isn't anchored.

JL

Remember it's a bit uncomfortable to be jerked off the ground and then suddenly stopped by a anchor so the belayer has to keep the anchor taut. Additionally as stated before it'll make the leader's fall more dynamic.

In such a situation, your belayer should camp out as close to directly under the first bolt as possible. Being jerked straight up ain't so bad, but having to deal with swinging too can cause a person to lose control of the belay.

This is the route description of Swinging Sirloin at Castlewood:
"The furthest route left on the Falls Wall is a steep little thing that arcs a bit left on sharp edges and thin pockets. Named during the FA when Mike Lane took a whipper lifting his belayer half way up the route. Nice continuous climbing with good solid climbing."

I've pulled several belayers off the ground as much as 8 feet or so. I can think of very few sport routes that even have anything to tie off to. Every situation has its own answer, but generally I think its best for the belayer to reside 2-3 paces away from the wall so that there's enough reaction time to kick the feet up and cushion the impact of being pulled into the wall. The price for this is few more feet of dropping for the leader, so adjust this to thier exposure.

Now at the other extreme is the concept of "penalty slack" for bad form, trash talking, etc.

Keeping the belayer unanchored adds some dynamics to the belay, lessening the impact force on the bolts, draws, etc.
Anchoring the belayer also prevents the belayer from utilizing the "Edwin Moses belay stance" which is where the belayer can be ready to run downhill if the leader comes off high above the last piece of pro, thus taking up additional slack, which is often faster than yarding the cord thru the belay device.

Mike, I can't remember who was belaying you when you whipped on Swinging Sirloin. You, and I, were a bit lighter back then.
Who was the lucky guy who caught you?

I'm going for anchoring the belayer, then teaching the belayer how to be dynamic with the device & rope. Though this particular example is a single pitch sport route, getting the belayer used to anchoring transitions right into multi-pitch climbs.

One other thing I do is get the belayer tied into the back end of the rope, so a lowering accident is prevented.

A big assumption I read into is that the climber will remain on route & having bolts at regular intervals; any type of runout & fall is going to jack the crap out of the belayer much worse than taking those controlled falls in the gym. I'm still going with the odds in using anchoring as opposed to running away from the route.

I wouldn't bother with the anchor. Your fall will, if friction isn't factored in, only add up to like 87 pds of force. That's at most. Friction will cut that dramatically. by not having an anchor it will actually make the system safer cus it will add a dynamic flow to the stop.
The only thing is the belayer should be more or less straight under the first piece. If not, she is gonna get yanked into the wall.

Two points:

• Most people sport climbing don't bring trad racks or slings to build anchors.

• Many (most?) sport routes don't have any place to set an anchor for the belayer even if they did have a rack and slings.

One assumption I made in this particular question from Junior was having an anchor (natural block/tree, bolt, trad gear, etc.) available and then deciding whether or not to use it.

I think the question wanted to address the method of how we attempt soft-catching (dynamic belaying) & what position the belayer is in prior to the fall.


Also - If I'm 100% certain of the route & rope lengths, then I don't bother with the back-end; like N Table in Golden, everything is short. But to do the same thing elsewhere (or using someone elses rope), I go right into safety checks & tie-in both. Stopper knot works also.

I weigh 127 pounds and have climbed with many guys as big as you and have caught their falls easily without being anchored. I don't know how many times I've been pulled about 3-6 feet up the rock while catching fairly big falls, but with experience it feels totally safe and natural. The benefit is a dynamic belay and less complex rigging.

Having said that, I would recommend not anchoring if your belayer is used to catching lead falls - they are way different than TR falls. There is some multi-tasking going on for the belayer in this scenario. One, the brake hand goes back. But also, the light belayer will simultaneously have to put a foot out on the rock or he will get scraped up the face. If its a big fall, he will take a couple steps up the wall while the climber is pulling him up with the force of the fall. If you don't think your belayer is capable of that, maybe its better to anchor.

And of course your belayer is wearing a helmet the whole time and is not standing out from the wall nor under a roof.

In college I weighed 170-ish. My 2 lighter partners weighed in at ~125 and ~112, respectively. The former rarely got much more than a few feet up, but for the latter, I frequently skipped a clip or escewed low gear on overhangs to prevent whacking her into the cliff. There is a fine line and some of it depends on how many pieces you place.
Eventually, we settled on clipping the lighter of the two to a pack full of whatever, like water jugs and such, so that if she got picked up more than a few feet, the leash would go tight and that was it. It worked pretty well.