How much stress gets put on the bumper guide on a bumper wrap rod? On my UL I taped up a single-foot 6. Is that going to be strong enough?

I believe Tom mentioned this earlier in his series on bumper wraps, consult him for the final say so but here is my understanding of the layout. The bumper guide should not experience any other force than that of being pressed directly on to the blank. No torsional load is experienced when the guide is placed correctly. I have been using #6 guides for bumpers with no hang ups. I am wrapping light offshore rods for snapper. As I mentioned earlier these rods fish most pleasantly, a real delight. I do not underwrap, I feel this is overrated for the size rods and guidesI am making.
Secondly, if you have placed the guides and run a static load check, when looking at the bumper guide you will see that the line contacts the guide at the bottom of the eye, no where else. If it is, the guide is not yet at its correct placement.

Curtis Beers

Curtis is right. The direction of the vast majority of any force on the bumper guide is directly down toward the center of the blank. Single foot guides, especially those that sit low which you want to use, are more than enough to withstand the force of the line.

The only reason I put double foot guides on my spiral wrap rods is that the lower guides nearer the reel tend to get the most physical abuse, normally form laying the rod down on the boat seat or bumped on something. The blank section where the lower guides reside is stiffer than the tip and not as forgiving to bangs and bumps plus the weight of the reel is close at hand.

If you use your UL rods like I do, I think a single foot guide is fine. I would not do it just to save weight as I doubt anybody holding an UL rod of 7 feet can feel the difference between a single foot and a double foot guide. And since that portion of the rod flexes very little if at all, weight is of little concern.

The bottom line is you can use either one you want but if standing up to any abuse at all is a concern, go with the double foot guide.

SHORT VERSION:
"How much stress gets put on the bumper guide on a bumper wrap rod?" - HARD TO SAY. Should be "zero". Good luck.
"On my UL, I taped up a single-foot 6mm. Is that going to be strong enough?" - MAYBE NOT. Try a low-frame, double-foot.

LONG VERSION:
THEORETICALLY, the only force on that 90 degree axis "bumper" guide should be a light force that is perfectly perpendicular to the rod blank, pressing the bumper guide directly into the rod blank, NOT torquing it around the rod blank like a wrench handle.

For that ideal condition to be met, it requires that the line touch the bumper guide pretty much only in the bumper guide's 6 o'clock position. That is, only DIRECTLY over the feet (or foot bridge) of the guide. If the fishing line is touching the ring of the bumper guide at some point much away from that 6 o'clock position, like the 3 o'clock, then the lever arm is significant and the force is rapidly increasing. (I'll spare both of us the trigonometric vector calculation. Suffice to say that only when the line is near the 3 o'clock position in the guide ring can any stable lever arm be established, and pose a legitimate probability of generating a significant lever arm length and angle to torque on the guide.)

If you have ring contact somewhere other than the 6 o'clock position, then you may need to move the bumper guide to a more "neutral" position. Or move the 180 degree guide accordingly.

If you like, you can use a simple way to calculate the force torquing on your guide by simply using a small-range fish weight scale. Hook the fishing line near the bumper ring while the rod is under said load, and see how many pounds it takes to lift the line back into the 6 o'clock position. This technique is an indirect technique which directly measures the OPPOSITE (or "neutralizing") force of interest. (Multiply the height off the blank times the neutralizing weight, and that's your torque, just like for your mechanics torque wrench.) With your UL outfit, it should be less than one pound, in which case you could throw a fish hook on a short line around the fishing line instead, and drape the line over the other side of the rod blank, and hang one ounce sinkers off an end loop until it pulls up the line inside the bumper guide's ring back to the 6 o'clock position. You might get some crazy units like 8 centimeter- ounces. ...

And exactly what will that tell you ...?... Not much, until you do a FAILURE TEST with a guide on a scrap blank and see how many centimeter- ounces it takes to "rock" the guide in its thread wrap or crack its epoxy. Here if your torque wrench won't work in this configuration, then just hang "X" pounds off your test guide and see when it starts to "list". The torque will probably be ~ 100 times higher to rock the guide than to move the line from the 3 o'clock position back into the 6 o'clock position inside the guide ring.

By now, I'm sure you are agreeing that it is MUCH easier to just adjust your bumper guide and take it from there. ... But I am always a little amazed when I read a question like this because even if someone could give you the torque values, it wouldn't mean much until you understood how to measure it for yourself or apply it to your own situation. ... I hope this helps.

Or you could just quick-wrap a guide on a scrap blank, and yank & crank on it to see if your wrapping technique will keep it secure. Ultimately, Leon, that is the REAL test. Because nobody here can judge the width of the guide's foot compared to the rod blank's diameter (OD) under the bumper guide, which effects the "rock-ability. And we can't tell how deeply bending the rod will move the line in the bumper guide ring toward the 3 o'clock position, thus maximizing the lever arm and therefore the torque force. And we can't feel how hard the line is pressing around & into the ring of the bumper guide, or tell how much the line shifts around inside the ring. We can only guestimate. You are right there.

The consensus seems to be that a LOW-FRAME, DOUBLE-FOOTED bumper guide is more stable than a single-footed, V-frame or Y-frame guide, because of having two bands of thread securing the bumper guide from rocking, and a LOWER height off the blank for the guide ring in the first place. That geometry in your bumper guide will help to keep any torque forces on your bumper ring and guide at a MINIMUM, even if there remains some non-ideal line contact and pressure when the rod is under higher loads. Some people seem to be trying FLY guides (single-foot, single-leg) as bumper guides for such UL rods.

So, that's the short and the (too) long of it. ... IMO, short answers only work when we are all on the same page, which is often NOT the case. IMO, -Best Wishes- , -Cliff Hall, Gainesville, FL-USA+++

Curtis is dead on the money. If set up properly, the bumper guide receives no stress whatsoever. The only place the line will touch it is in the very bottom of the ring - directly against the rod blank. Remember, the bumper does not transition nor direct the line to the bottom of the rod. It only serves to keep the line off the blank as the line passes by on that one side.

..........

Put pressure on the rod. If the line presses on the side of any guide, just move it so the line rests in the center like said at 6 oclock. You want the streightest line path.

The sz. 6 will do great. If wrapped with a forhan locking wrap, even some sideways pressure (with the rod loaded fully) won't likely pull it out or damage it in any way. Those single foot guides are mighty tough. The worst abuse it will get will be going in and out of the rod locker, or getting stepped on while on the boat deck.

There are many smarter rod builders than myself, and many with much more experience, so take this next statement with a grain of salt. I don't ever use a double-foot guides anymore, except on larger rods (i.e. rated to handle 20-40 lb. line or more). And, I try to use as many "fly" guides as I can. When I need a higher frame guide, I use high-frame single-foot spinning guides. Other than the possibility of rod locker accidents or stepping on guides, I just don't see how there's any disadvantage to the single foot guides.