How to drill a nightrider 36 rim?

Hey guys, figured I’d ask people who know more than me about this before actually doing something (and besides I’m a few thousand kms from my 36 with this rim on anyhow…).

I heard from Sam W (redwelly) that drilling the inside of his nightrider rim out only saved about 50 odd grams (compared to airfoils which dropped much more - thinner inner wall metal on the nightriders apparently). Since riding his wheel with shaven tire, 29’er tube, ss spokes and drilled rim, I really want a similar setup. The weight savings is ridiculous - and when I get a schlumpf for it - mm!

He was saying that the metal is much thinner on the inner wall, which makes me wonder - how dangerous/unwise would it be to drill out the outer wall of the rim a la 19" trials gear that’s going around right now? I’m a road weenie as is, so strength isn’t a super huge deal to me unless the wheel is flopping every which way and running into my brakes, so if it would hold up to road riding I’d be all for it.

My question is, what would happen? It would really suck if building the wheel back up caused the rim to die in weird ways, but it also seems like the weight savings would be worth it, especially if it was on the order of 100+ grams at the extremity of the wheel.

And besides, I might try it anyways and risk having to buy a second rim to mess up, who knows? :smiley:

Hey Dave

I was thinking the same thing but don’t have the rim to drill out yet. I think it would be safe as long as you keep it for road use. When I have disposable income again I plan to build up a super light geared 36er for pure road riding.

If there are vertical walls between the inner and outer walls you would want to make sure that you keep those intact and the rim should be fine.

And when you tried it, it even had a 36" tube in (after my 29er blew out before the marathon). It should have been lighter than that! :wink:

Sadly the shaven tyre thing means it doesn’t last very long - I think the compound is a bit softer than the TA, and mine is showing threads at several places (not just turning spots aligned with the cranks either), after cutting it down to about 1mm of groove depth and then riding it about 1600km. Now it’s going to be kept as my racing/record breaking tyre and I’ll go back to another one for everyday use.

On my rim I drilled three 1/2 inch (yes, randomly imperial drill bits) holes between each spoke, and enlarged the spoke access holes to the same 1/2 inch size. I also did 4.5mm holes in each ‘corner’ of the big holes - running in two rows around the sides of the inner surface. That was a lot more work for a lot less benefit than the big holes, but looks quite cool. The whole thing took three hours with a pillar drill (in a physics workshop at my university), and I finished with a Nightrider Pro weighing 1069g.

Yeah, I’m tempted to drill the outside (visible) surface as well and see what happens. When I get home from work I’ll find photos of what I have done so far to the inside of my rim.

Sam

drill the sidewalls!

that would really make braking an experience.

Glad to hear others have been thinking of the same thing though…

I was planning to do it. But remember that it is the rim that has most to say when building a strong wheel. A heavier rim means a stiffer wheel in most cases. I was spoking up the new nightrider rim but I thougt the rim was to soft for me. I do mostly Coker Muni. Havent tried the nightrider rim, but when building the wheel I realy can feel the airfoil is a lot stiffer. That bacause of a deeper cross section rim is a lot stiffer than a ordinary cross section rim. But I guess a drilled rim works if you mainly spin on the flat.

Here are some photos I took while drilling my Nightrider.

The outside edge of the small holes was just starting to cut into a vertical part inside the profile of the rim extrusion, so I think that’s about as wide as you can go with drilling holes across the surface.

I’d definitely recommend using a pillar drill for this as you need the height control to not go too far and get the second surface by accident.

I didn’t weigh my actual rim beforehand, but going by the stated weight of 1116g, and my measured ‘after’ weight of 1069, I saved 47g. :sunglasses: (Ironically I threw away 20g of that by building it up with brass nipples - it’ll be blingbling gold alloys next time)

Sam

drilling-1.jpg

drilling-2.jpg

drilling-3.jpg

Dave, be brave and do it for all of us poor people. :slight_smile:

EDIT: Sam: Did you have to use special rim tape after you drilled the rim?

Nope. Maybe I should have, but I just used ‘normal’ hockey tape. Apprently it is lighter than other rim tapes, but it is also absorbant so gets heavier if it’s wet! The pattern of holes is narrow enough to allow decent enough coverage with one loop of tape - again, saving weight. I guessed that each circumference of tape is about 20g, so you don’t want to do two unless you really need to.

I’ve taken the tyre off several times now, and the tape is getting quite peeled back in places, but I’ve had no problems with it so far. All the holes have a chamfered edge so they aren’t sharp.

Sam

Do you think the rim would be too weak with gears (single or double wall drilled) or is it not an issue?

Might be wise if one were to use hockey tape not to drill the outside of the rim, lest water get in and cause the tape to be less sticky?

I’m thinking I will drill some smallish holes between the spokes on my nightrider when I have access to both a scale and a drill press in the near future. though the thought of having an extra 50g off the inside of the wheel is appealing… :smiley:

it’d suck if say you couldn’t ride it in the rain though.

And scott: if you could put a ‘fixie’ on the rim drilled I’m sure you could get away with geared. I’d be curious to know if the benefits of lighter wheels are amplified or lessened or stay the same on gears as well.

Might be wise if one were to use hockey tape not to drill the outside of the rim, lest water get in and cause the tape to be less sticky?

I’m thinking I will drill some smallish holes between the spokes on my nightrider when I have access to both a scale and a drill press in the near future. though the thought of having an extra 50g off the inside of the wheel is appealing… :smiley:

it’d suck if say you couldn’t ride it in the rain though.

And scott: if you could put a ‘fixie’ on the rim drilled I’m sure you could get away with geared. I’d be curious to know if the benefits of lighter wheels are amplified or lessened or stay the same on gears as well.

If you use hockey tape, and the rim is drilled all the way through, would water getting in at the tape be an issue? Could you stretch a 24" ‘thick’ (for drilled rims) rim tape over it and still be okay?

I will be drilling outside holes on my nightrider once I have access to both a scale and a drill press, so we’ll see. I’m thinking I might not drill out the inside until I test the strength of the outside first. An extra 50 grams off is not bad though, every bit counts for sure.

also scott, I think that if it holds up to normal ‘fixie’ use then it should be fine on a geared. What I’d like to see is what difference a lightweight wheelset makes to geared hubs vs. stock weighted wheels. Does it help more, less or the same?

Someday I’ll have the gear to answer these questions :wink:

On UDC the KH rim strip is only $4 and is pretty stretchy, so you could try it.
In theory, the faster you go the more weight matters because as the wheel spins faster, it makes more centrifugal force, and on a guni you go faster so it would matter more than on a fixie. (I think)

On geared 29er a lightweight wheel makes way more difference than on a normal 29er.

Joe

I doubt you could stretch a 24" rim tape that far.
for rim tape you coudl do what most trial bikers do on their 26" wheels and use electrician’s tape or duct tape. Or maybe get 26" rim tape, more chance of going all the way round a 36" wheel. Still think it’s unlikely. get two and stick em together?

One idea is to get two 24" Kh rim tapes and stick them together. The problem is that they are for the drilled rim so you would probably have to heat them and fuse the plastic together, but I don’t know if that would work.

I’ll just go the hockey tape route - it’s plentiful in canada :stuck_out_tongue:

Okay, so an update on this. I drilled 34 (decided it was unwise to widen the valve hole or drill a huge hole over the rim join) 3/4" (1.9cm) holes in my nightrider. It looks pretty badass, and I’ll post pictures a bit later. I don’t have the equipment to put smaller holes on the inside diameter of the rim, but the final weight ended up at 1048g. That’s a whopping 68 grams off the stock wheel!

Now I just have to rebuild the unicycle, and see if it was worth the trouble and if the weaker rim holds up.

After I shave down the tire and swap out my rim strip, I’m looking at a half kilo (providing my tire tread removal estimate is right) of weight off a nightrider tire/rim combo with a 29’er tube.

woo!

Sweet stuff Dave, what are you using to cut the tire?