Drilled vs solid un-drilled rim pros/cons?

I’m choosing bits for my new mad4one 29" unicycle and I’m trying to decide whether to get the drilled or the un-drilled rim.

Drilled mad4one 29" rim:
Pros: Accelerates faster which helps when taking off from a stop, lighter (838 g), looks cool
Cons: Weaker, costs more (+5€), dirt can get inside holes, harder to clean

Un-drilled mad4one 29" rim:
Pros: Stronger, chheaper, better at keeping rotational momentum which is good when rolling over bumps, no holes for dirt to get into, very easy to wipe clean
Cons: Heavier (929 g), accelerates more slowly (is it noticeable though?), unexciting looks

Need to hear your opinions to help me decide. My gut tells me to go with the un-drilled because I have a uni with a drilled rim and it was a PITA to clean after riding through a muddy patch, but I have no idea how the extra weight will impact steering and overall feel. Cost really isn’t an issue because the difference is minuscule, but I included it in the comparison for completeness’ sake…Thanks in advance!

Wheel weight is a lot more noticeable on unicycles than bicycles, because your feet are directly attached to the wheel, and because you move the wheel back and forth somewhat independently of your own weight. It’s not just that it accelerates faster when you start out; it’s more maneuverable. And 90g is a lot, especially for a tiny price increase.

OTOH both rims seem kind of heavy compared with bike rims, or the KH 29" rim (wider and says it’s 745g).

I’ve only ridden drilled rims on trials bikes and unis, so I don’t know how that works out for muddy riding. The KH line moved away from them, mountain bikes never really used them, so folks seem to think it’s better to design a light rim, instead of drilling out a heavier rim…

I didn’t know that! Just checked KH’s website and the 27.5 and 29 are marked as “NEW!”, and they no longer have the drilled rims. Indeed these are lighter, and they even have eyeletted spoke holes.

The only problem is KH seems to be out of stock everywhere because of COVID-19. I’ll see if I can get a similar rim and mail it to mad4one for lacing.

I don’t like drilled rims as you need to use a strong and heavy tube to avoid flats which makes much more weight impact than holes …

Does KH sell the rim separately, or the whole wheel? Else, can you guys recommend a similar rim? (29", 36H, wide and with eyelets). I like KH wheels but I prefer mad4one for everything else.

If you’re worried about dirt, you could always put a piece of cellophane tape over each hole.

1 Like

That would be very messy

Last I checked UDC USA had the KH rim available. Shipping might be expensive though.

EDIT: nope, sorry, looks like they only have the 27.5.

36 hole is going to limit your rim options a bit. The alternative is going with 32 hole, which opens up your rim options. As far as I know there’s only one hub 32 hole hub (Nimbus), which is also in short supply at the moment.

Just a note however, a friend had some problems with the KH rim being wide as the choice of tyres are drastically reduced. Keep that as a consideration too.

1 Like

For what it is worth, LightBicycle will do a 36 hole made-to-order carbon rim for you if it isn’t a stock item. I have bought a few rims from them and have been pretty pleased with the results (on both bike and uni) – as a note, I have absolutely no affiliation with them other than being a satisfied customer. That will get you the low weight/moment-of-inertia with no drilling issues and a pretty nice looking rim with the carbon finish you choose.

If cost isn’t such a problem, the only potential issue may be lead time if it is made to order, check with LightBicycle directly to see what the lead time would be.


Coincidence! I happen to be building up a 32 hole LB custom rim, with a 36 hole Q-axle hub. Not on purpose; when I ordered the rim I thought the hub was available in 32 holes, but that turned out to be only the aluminum axle, which I didn’t want. The Nimbus hub is a lot heavier, and more expensive; plus I wanted to use the Qu-Ax Zero-Q cranks. So I ended up with the mismatch.

I’ll post about the 36-to-32 process in a couple of days once I have it up and running, but it’s not too painful if you are comfortable building wheels. But if you are having Mad 4 One build the wheel, you’re stuck with matching components.

LB is really backed up; it took about 2 months from finalizing the order to US delivery.

1 Like

WIdth is 55 mm, it’s pretty wide. What’s the narrowest tyre you can safely put on that rim?

Unfortunately those escape my budget, though they look nice.

Not something I can answer for sure (not my uni or rim) but I’m sure someone will know. :slight_smile:

You’ve probably got several decals on your unicycles already. They’re about the exact same thing as a good grade of tape.

Myself, I peel most of them off my own unicycles and bikes, but if they actually served a purpose like keeping out dirt then they’d make more sense. Mr. Yuk stickers might work well.

Good to know – I was about 3 - 4 months for the Falcon Pro rims I got for my gravel bike build recently, admittedly that had Chinese New Year in the middle which adds a few weeks, so it seems to be an ongoing backlog.

It wasn’t really an issue for me since I was buying other bits for the bike as availability allowed (both part and money availability!) but fair enough if you want something a bit more timely.

I had a discount on the last ones since the carrier basically lost the uni one before that and it had to be remade, then the original turned up several months later – so that made the price a bit more palatable. They are a bit of an indulgence though.

Hmm, municycle.com have just emailed me back and they have both the Nimbus 29" Hatchet rim and the KH 29" Freeride rim rims in stock!

I’ve never used such a wide rim (55 mm). How does a wide rim affect handling? What’s the narrowest tyre I’ll be able to run?

To the original question. Undrilled vs Drilled rim: ~90g difference is very little if you take into consideration the weight of the tube (150-250g) and the tire (600g-1200g?). I would not bother to save 90g for the inconvenience of having “holes” in my rim.

If you wanna go lightweight and carbon rims are to expensive (and you don’t want to wait months for delivery). Why not just get some light aluminum MTB rims. I run some Spank Spike Race 33 rims and they are ~500g. Sure they are 32h so it’s best to get a 32h hub but you can also match with a different hub which would make wheel building slightly more difficult and maybe affect the strength slightly due to the uneven distribution of forces on the flange of the hub.
It would probably be the easiest to build on a 48h hub. Then just skip every third hole in the flange.

Sure carbon might be stronger and the Nimbus or Kris Holm rims might be stronger, but the question is if the extra strength is really needed.

A had i KH29 with one of those very wide rims until a few days ago where I sold it to a friend that broke his (very old) Uni and was in need for something to ride.
It is running a Continental Speed King 2.2" and that is fine. It looked massive as the rim made it wider than 2.2" (and maybe gave it a more flat profile) than on a “regular” rim. I think you could mount a 2.0" on the rim but due to the very wide rim the tire will very likely measure more than 2.0" on the outside.
My 27.5" (so only slightly smaller) on the light Spank rim and almost the same tire except for a few knobs (Continental Race King RaceSport 2.2") seems much more manageable for me. But if it is the change of size, change of rim width or the weight of the rim is hard to say. Should notice that crank length is the same on both (125mm).

1 Like

Just the answer I needed, thank you! I actually prefer a flatter tyre profile, so the wider rim might actually suit me. The tyre that came with my old KH27.5 had a very round profile and it was very susceptible to camber. This was especially problematic, at least for me, when riding on uneven terrain, but then I switched to a Maxxis Minion DHF 27.5x2.5, which has a flatter profile, and things improved a lot.

I have a drilled rim on my 27.5 Fat Mad4one, and similar comments as the other person. The 100g makes a difference but isn’t super noticable. If weight is a concern then the it’s better to build the uni price by price, I did this with my mom is road 29 and found that I saved about 700 grams off the wheel. It made for a much more responsive uni and I’d say anything under 300 grams won’t make a huge difference. Given that tires can range from 500g for small light weight MTB tires to 1.2kg for fatter or cheaper tires it may be a better place to try and save weight if you want to. That being said more weight on the uni means it is more planted and stable. More agile isn’t always the ride ride you want as doing muni on my 29 can get me small bits of air at times. It all depends on the ride you want.

1 Like

Part of the problem is… I don’t know the ride I want. Where I used to ride it was all smooth tarmac so I never experienced off-road. I moved into a country home six months ago and I’m looking forward to hitting the trails (I don’t have my old uni here).

I think the rotational momentum of a heavier wheel would be useful when riding over bumps at speed, because the wheel will tend to “keep going” so the chances of a UPD, in theory, would be reduced. However, at slow speed over very technical sections the extra weight can get in the way. That said, weight is easy to add (e.g. a thicker tube or even ballast, such as a lead strip around the inside of the rim, if I really want to experiment) but hard to remove, kind of like salt from a dish dish that’s too salty. I think starting off with a light rim would be the most flexible set-up in terms of weight.

Also, the Nimbus rim is cheaper. The Mad4One rims are the heaviest and and don’t have eyelets, and yet they are more expensive. The Mad4One site says eyelets are only needed when using alu nipples to prevent (seizing I guess?), and mentions a number of disadvantages. In my opinion they didn’t add the steel eyelets because their rims were already too heavy to begin with, and also because it adds to cost.