if youre top roping in the gym you will be fine. If youre taking a lead fall she will probably get lifted off the ground a little but nothing serious. Its not like she will get shot up to the top of the climb. In a standard toprope set up the belayer will feel 60% of the force due to friction. Using a grigri will lift her off the ground even more because it gives a static belay.

Search the existing threads. If you use the words "belay" and "weigh," I have no doubt you'll find what you need (and oh so much more). Cheers.
BTW, most gyms provide floor anchors, so this should be a non-issue.

It's fine...hell its even fun. When my son was younger there was at least 100 lb difference and taking a whipper would drag him up to the first anchor... A total hoot. He had an ATC XP for added assurance, but in retrospect I think a regular ATC would of been fine...

Does using a Gri Gri make you feel safer? Even though it's auto locking, user error is still possible. Just anchor into the ground before belaying your partner, even without being anchored in, getting pulled up isn't that big of an issue. Providing a dynamic belay is better on the system.

>Cam

Having your belayer pulled upward and off balance is not the best, especially for an upcoming and coming novice climber. IMO don't foucus so much on the hundred pounds but rather the weight ratio between climber and belayer. Basic somebody can belay a climber 1.5 times their weight in good conditions. Gyms often offer ideal conditions for belay stance and position. If you never leave the gym then this is all you need to know.

When you start climbing outside you are inevitably going to encounter less than ideal belay positions and you will need to start considering a ground/belay anchors when ratio exceed 1.2 or so (this is not an exact science - or actually it is but I'm not going there).

For an example if my wife weighs 130 lbs. and I weigh 190 lbs then our weight ratio = 130/190 = 1.46 when I am climbing. She is a good belayer and can hold me without to much additional effort in good top roping scenarios. Leading is different so we take extra precautions when conditions are less than ideal (e.g. gri-gri, ground anchor - but not too tight to keep some elasticity in the belay system)

Using a grigri, how exactly does said belayer lower back to the ground? lol

Sketchster,
I am surprised that your local climbing gym doesn't have ground anchors. I am not a gym climber but I always thought that most gyms could accommodate folks in need of a ground anchor. Have you asked? What climbing gym? Either way with a ratio like 1.6 you are always going to be dealing with anchoring the lighter belayer. Good luck and climb smart! Don't let the knuckle heads in these forums sway your common sense.
Cheers

Yea, they definitely do not have anchors. The place is called Joe Rockheads, in Toronto.

My wife took a lesson and their recommendation was to twist the rope twice at the top. The advised that this is bad for the rope, but would not compromise safety, and allowed my petite wife to belay me just fine. She even caught a fall!

And if therre is a roof--make sure to wear a helmet! I've been pulled up and knocked on me noggin!