Cut it and measure if necessary , I got those wheels for very little money.

Yes, when someone I don't know say I act like a dick.

So you will cut and measure them. Then what? I thought the purpose of this experiment was to lighten up some wheels you got cheap? You will cut one to measure and then shave the other?

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www.ergottwheels.com

Assuming rim go to trash after cut out is not the absolute destination. Besides, there are plenty of very cheap R500 around where I live.
''So you will cut and measure them. Then what?'' - Shall I ask why you said ''Do you even know the wall thickness of the rim where you plan on shaving?'' in the first place? scratch my head

Everybody stop! This is darwin at work, we shouldn't interfere.

Someone should alert Richard Dawkins...

+1000

Ergott and others with far more knowledge/experiance than the OP - good effort - too bad it's falling on deaf ears..........

I did a WW experiment witha pair of WH-R550. I managed to do the following:
1. took the stickers off: -20 g
2. changed the freewheel body to a NOS 600 7-speed (I can use only 9 cogs of a speed cogset, just like on a Campa Ghibli disc), changed the spacers to Campa aluminum, redished the wheel and made it a lot more solid: -35 g
3. changed the front axle to aluminum and rear the axle to XTR titanium: - 45 g

This is 100 g savings, and I ended up with a much stronger rear wheel, with minimal rear spoke tension difference L/R. So I have the one and only WH-R550 under 1800 g!

Yeah, but don't you know, you can swiss cheese the rim!!! That will save 50 grams and improve the strength of the rim. The wheel will ride much better (be more confortable)

Does anyone know if the rims are heat treated in any way? I know they are extruded and either pinned/welded but I don't really hear much about what heat treatment they may/may not have undergone. which may ahve an impact on what the OP is trying to do here. heck i don't even know what material those rims are made of.

ME eng. student here. I would not attempt it without pretty precise calculations with some sort of CAD software, for the following reasons.

1) drilling holes into the rim is going to create stress raisers, which are points where cracks can begin and grow. the haphazard way in which the OP is going about doing this means it is also unpredictable how these stress raisers will influence other aspects of the wheel- the introduction of a stress raiser will affect how other things like spoke holes, tensions rise. while the strength of the wheel is in the spokes and not the rim, the rim still has to withstand the tension that the spokes place on it.

2) drilling/machinign the matieral is going to alter it's properties somewhat- it's going to have micro stresses which will make it more brittle. I'll admit I dont know exactly how this will work, but having a brittle rim is not my idea of safe.

3) the wheel is going to undergo cyclic loading, which means it IS going to fail eventually, even if undrilled. us engineers refer to something called design for fatigue failure, which means your wheel shows signs of dying long before it actually does, which means it's time to get a new one. altering that design is going to mean you have NO idea how weak or strong the wheel is or how many stress cycles it can withstand.


I will admit that such wheels with holes do exist. some are even manufactured with them on purpose ( BMX trials wheels, I've seen a few.) but these are all done with careful PLANNING and testing and they are built of massively strong metals and are wayyy overbuilt ( I handled one of those rims once- the 20" BMX trails rim with holes all over was about the same weight as a 700cc rim. which is saying much given its much smaller diameter.) even so you will need high quality tools and machinery to make sure you DRILL IT RIGHT without chattering or damaging the rim. I could very well imagine a pinned and sleeved rim breaking at the pin if you dont drill correctly.

but hey. you want to try it? it's your cash. and your life.

I have asked these simply strict questions in my previous posts.
1. Correct me if I am wrong. Yes, rim is designed to have hole cut in between spoke holes, i.e. hole for the tube valve. I have not heard of failure at the lower bridge of the rim between spoke holes or certainly not at the hole for the tube valve which is located in the middle between spoke holes. So, at least it would be safe to drill holes of the same diameter at the lower bridge in between spokes holes ?
2. Please explain to me why you wouldn't worry about the valve holes which go through both bridges of the rim ? I suppose the thickness of lower bridge has been designed to have the strength to take the force of spoke, therefore it could be considerably overbuilt in between spokes. Proof me wrong if you have better answer i.e. testing/calculations/computer modelling that you have heard of on this subject.

Hey, i hadnt bothered reading this thread until now, im surprised at all the negativity. I mean, this is weightweenies, were all taking slightly larger calculated risks with 60g carbon stems that have not been properly tested, using hollow ti bolts (or aluminum!) for everything...
Somewhat back on topic, ive drilled the inner wall of my rims before. They were mtb rims, they were bontrager mustang tubeless offset rims. I drilled one hole in between each spoke hole, the same size as the one already in the inner wall, for the rear rim. For the front, i drilled the same size holes, but three per space between spokes. I may have gone back and drilled pairs of smaller holes in the rear rim after that, i dont remember.
The wheels held up pretty well, even with the ti spokes i was running. It was all on an original scalpel, rolhoff on the rear, but thats another story...
Eventually, however, i was mounting a new tubeless tire and the sidewall blew off the rim. The side force bent the rim a bit. Inspecting the damage, you could see the holes were askew somewhat, like crooked ovals, to allow the bend. It's interesting how much the rim's cross-sectional TORSIONAL stiffness and strength is involved in rim deflection, etc...
Greg

Some say we have stopped evolving because we preserve our idiot genes. This appears to be wrong.

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r o y g b i v

How many spokes and what hubs? Being an MTB wheel I bet it was a much more robust set of wheels than a set of R500s. Did the wheels feel a lot softer after you had drilled them? Any spoke failures before the blowout?

Also how much do you weigh?

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DO IT!

Ride it.

Take pics.

Come back here and post.

(that's called the scientific method based on experience, WW style).

Louis

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http://www.ccsalma.com

32 ti spokes, 3x up front on a lefty hub, 32 ti spokes 2x on a rohloff on the rear. rims were just over 400g before drilling, which was some of the lightest back then (pre-stans). wheels didnt feel any flexier, but tires were very light (conti explorer supersonic, tube free) and the rear was mush to begin with as it was on a 1st gen scalpel. no spoke failures at all with that setup, even after i smacked that front rim straighter and trued it up best possible. only used this setup for just over a year though. this was all done many moons ago. i weighed 165lb at the time.

forgot to mention, funny thing was all that drilling barely saved any weight. dont remember how much, i do remember i was surprised and disappointed.