Actually on trials bikes its common to drill holes straight thru both the walls between the spoke holes. No it won't make a difference in wheel strength.
Lightening rims
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You'd save less, 40g a rim, that's 10%. If you look at a rim in pieces the length between 2 spoke holes, 10% off that is a LOT. I've been thinking about this somewhat as well. I'd see more in sanding down the spokebead and sidewalls. Drilling is step 2 
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Hi,
I did this trick on my M*avic 317s and it's still pretty strong, but I weighed the before-and-after thing..... I saved 4 grams on each rim, which is not a lot. I was thinking of drilling two holes between each spoke hole, but I tried to keep the strength of the rim. Maybe it would be strong anyway.
Don't worry about the strength of your rims after the drilling, it will hold up !
Jean-Sebastien
Hi,
I did this trick on my M*avic 317s and it's still pretty strong, but I weighed the before-and-after thing..... I saved 4 grams on each rim, which is not a lot. I was thinking of drilling two holes between each spoke hole, but I tried to keep the strength of the rim. Maybe it would be strong anyway.
Don't worry about the strength of your rims after the drilling, it will hold up !
Jean-Sebastien
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Funny, I did the exact same thing and saved 5 grams! I drilled an X317 that was pretty much ready for the trash bin (lots of dings) so I didn't have anything to lose. I was hoping for at least 10 grams. Oh well. I really doubt the strength will be affected as long as the holes are clean (no sharp edges to start cracks). It took far less time than I thought (maybe 15 minutes tops with a drill press including center-punching each hole). I didn't drill a hole at the weld area. I figured that was asking for trouble and, besides, leaving that material helps balance out the valve stem on the opposite end!
Now I wonder if it would be worthwhile & safe to drill my Stan's rims.
I drilled an X317 that was pretty much ready for the trash bin (lots of dings) so I didn't have anything to lose. I was hoping for at least 10 grams. Oh well. I really doubt the strength will be affected as long as the holes are clean (no sharp edges to start cracks). It took far less time than I thought (maybe 15 minutes tops with a drill press including center-punching each hole). I didn't drill a hole at the weld area. I figured that was asking for trouble and, besides, leaving that material helps balance out the valve stem on the opposite end! Now I wonder if it would be worthwhile & safe to drill my Stan's rims.
this drilling trick works really well for trials rims because they are wide (for stability). The wider the rim, the larger hole you can put through it.
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compare those big holes to the nipple holes. I have one of these rims and there's no noticeable strength difference, but a big weight difference. As liberal as I am with the drill though, I wouldn't drill any rim less than 23-25mm wide, there isn't enough width to have any deadweight material, on thinner rims all the material is needed to keep its structure (I'm sure some engineering type can elaborate on this, it's the same principle that allows shimano to have hollow cranks without much strength loss). I've got a rhyno lite on the front of my 26" trials bike which has half inch holes through the outer wall as well as having the whole inner wall dremelled out and taking around a third of the brake wall thickness off. This was more of an experiment with an old rim - I dropped about a third of the weight and it's been running with no problems for over a year now.
- Joel
compare those big holes to the nipple holes. I have one of these rims and there's no noticeable strength difference, but a big weight difference. As liberal as I am with the drill though, I wouldn't drill any rim less than 23-25mm wide, there isn't enough width to have any deadweight material, on thinner rims all the material is needed to keep its structure (I'm sure some engineering type can elaborate on this, it's the same principle that allows shimano to have hollow cranks without much strength loss). I've got a rhyno lite on the front of my 26" trials bike which has half inch holes through the outer wall as well as having the whole inner wall dremelled out and taking around a third of the brake wall thickness off. This was more of an experiment with an old rim - I dropped about a third of the weight and it's been running with no problems for over a year now.
- Joel
I didn't drill both walls... ?
you can see through only at the valve hole .
I didn't want the dirt inside either.
Cheers,
Jean-Sebastien
you can see through only at the valve hole .I didn't want the dirt inside either.
Cheers,
Jean-Sebastien
sorry, just came back from a 6 hrs car ride at 30° and my head felt like an egg boiled for 3 minutes only :-/jean-seb said:
I didn't want the dirt inside either.
Cheers,
Jean-Sebastien
i took only a quick look at the rim
btw: i raced the national hillclimbing championships this weekend. what a WW event
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