I weight 130lbs, just brought a pair of very cheap Shimano WH-R500. They are really heavy. I wonder if it is feasible to shave material off the rims in between spokes similar to those higher end factory wheels ? Or even make cut-outs between spoke holes since it would be much easier than shaving by hand tools. I notice that there is drain hole at the side of the rim, I suppose cut-outs are just bigger holes.

I wouldn't do it. The wheels are just fine for what they are and what they cost. By the time you have removed enough material to make it feel just a bit more nimble, you've probably considerably reduced the durability, or even safety. The low spoke count relies on a stiff rim, compromising that is asking for trouble.

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Think of it this way -- you are already like 27lbs ahead of that 160lb-guy riding a $20K ww bike.

More seriously though, I wouldn't do it. Each properly engineered product has gone through intricate calculations and testing.

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agreed.

don't attempt unless you own some computer modelling software that can test them for you. you're better off just buying a pair of lighter wheels. less hassle , too.

+1
If you want lighter but cheap I'd be inclined to build a set from scratch with Kinlins and Hub Smith (or similar) hubs.

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If you think you can mill off 1/2mm of Al without damaging anything else then yeah go for it. Might save 50grams.

Please remember me in your will (but I don't want the wheels)

There is a reason nobody cuts holes/slots into rims to reduce weight-you would loose all rim stiffness and wheel integrity doing this.
Mavic & Campy/Fulcrum rims are designed to have very thick spoke beds specifically designed so they can mill away the material between and have nice strong spoke holes and thinner center sections that are still stiff/strong enough.

500s are not designed this way! Lighter Shimano rims reduce the wall thickness in specific areas so they can save weight but remain stiff/strong.

Its been a while since I've seen good drillium on WWs, but typically people drill out areas that aren't highly stressed. Rims *ARE* highly stressed!!

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I have a pair of Bontrager xxx lite carbon tubular wheels which weight 1kg less than the R500 inclusive of tires. I think of it this way -- the 160lb-guy has more muscle to produce power than a 130lb me + the percentage of increased weight is higher (2.2lbs/130+16lbs>2.2bs/160+16lbs), therefore the effect of the increase weight will be more significant.
By the way, I am eager to learn more about your folding Falco ti bike, have not heard any news about it lately.

Thank you all for your reply.
Pretty much all tuning of bike parts are deviations from the original design.
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 heard of failure of hub flange, spoke, spoke hole, etc. where they are designed for the purpose, however, 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 ?

That sounds more or less safe although it wouldn't remove much weight. Someone must have tried it.

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You can remove some material, but it's like trying to tune a truck into a formula one car. When you're done you'll still have a heavy wheel, probably just less strong and durable.

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Give this idea up pal. You bought a set of heavy low cost wheels - trying to cut chunks out of them to save a few grams is gonna turn them into a set of dangerous low cost wheels. If you want a visit to ER that's grand but your riding/race buddies might not want to join you on that trip. As somebody mentioned earlier, for the money you spent on the Shimano wheelset you probably could have had a nice lighter set of hand-builts, Dati hubs & Kinlin rims etc. Stupid idea cutting bits out of aluminium rims.

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Yes the wheel is strong enough with 1 hole drilled for the valve. But the reason you don't hear of rims failing at the valve stem is because they don't crack there, they just fold under a combination of compressive loads and spokes loosing tension.

The less stiff you make a rim, the less it distributes loads to the spokes, and the more likely it is to fold. This is why lower profile/less stiff rims typically have more spokes.

If you go drilling holes in the rim you reduce the integrity of the rim and give the rim more points to bend at both laterally and vertically.

If it were a good idea don't you think somebody would have tried it years ago and the idea caught on? Somebody might have-but they probably died before telling anybody about their great new design!!

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Saying new ideas stupid is stupid himself. Instead of quoting others’ say, why don’t you give your own legitimate technical idea?

Don't you think it is a bit harsh to say ''Somebody might have-but they probably died before telling anybody about their great new design!!''?, I would say fatality rate would be less than 1 out of 10, leaving at least 9 to tell the story.
If it were a good idea don't you think somebody would have tried it years ago and the idea caught on? - Perhaps I am a genius compare to all others.
More seriously though, I am looking for answers with legitimate technical idea/experience on the subject. If I could convince the industry experts here, I would try it out myself. In fact, I have done drilling holes at the upper bridge of a Ambrosio exellight rim of a front wheel for years without any problem at all. However, the wall thickness of the upper bridge is not thick so the weight saving there is little.

''The less stiff you make a rim, the less it distributes loads to the spokes, and the more likely it is to fold. This is why lower profile/less stiff rims typically have more spokes. If you go drilling holes in the rim you reduce the integrity of the rim and give the rim more points to bend at both laterally and vertically.'' - Stiffer isn't necessary better, mate! Especially when we are talking about radial stiffness, in fact, I found the R500 too harsh for me, harsher than any wheels that I have/had own. I suppose it is not going to give explosion, it will go out of true first before failure. It would not be fatal, this front wheel would - http://forums.roadbikereview.com/trek/b ... 04106.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;