Frames length

Hi,
I Wonder why there are no factory or retailer informations about frames length which could be helpful to decide on a purchase (could be critical for a 36er for example).
The only clues we have are the recommended leg lengths which are rather useless because it doesn’t take into account the various crank sizes, thickness of saddles and riding styles (also some riders like having stretched legs and some don’t).
It could be interesting to create a database with measurement from top to middle of the axis, organized by frame size in an updateable table.

So here is a link to a shared table including length, width, weight and material of each frame. Feel free to add a line near the appropriate size and brand (the software itself is in french but you only have to use one of the green crosses to insert a row) :
https://lite.framacalc.org/9pla-frames-specifications

Multiple entries for a single model are not to be excluded due to eventual discrepencies.

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Well, if that is important, I’d also publish frame width too since I tend to brush my legs on the frame, even to the extent of wearing the paint completely off my KH24 frame.

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Indeed, width at the widest point and why not add the weight including bearing holders to have a quick and easy overview of length, width and weight of each frame.

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Link to a shared table added in first post. Feel free to contribute.

I’ve always thought the inseam stated was in relation to the cranks in the specs, but maybe it isn’t so?

If you wonder if a uni fits or not, you should also know that you can cut the frame down by several centimeters. I did that for the kids when they were to short for a 29’er.

I did that for the 36". After I had done that free-mounting had finally become a lot easier.

You may be right, I don’t know.
But I find it odd that we don’t have the complete specs of a frame considering unicycling is tricking enough to require fine tuning, the length between the seat and pedals being a major setting I think.

I would be a little concerned to touch the integrity of a frame, but why not indeed.

It’s a service that UDC (UK at least) offer, I think on most of their frames on request, but as standard for their freestyle frames as they’re cut to your size.

The hard bit is slotting the frame again (neatly at least) once you’ve shortened it.

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Even that is pretty easy. Use a small drill bit and a small file and take your time. Drill a series of holes that are smaller than the slot should be and then use the file to connect and expand them. Using a punch to locate your holes is also a good idea and will keep the bit from wandering.

I’ve done it with a Sawzall too. Much faster, but also quite a bit riskier

It doesn’t really have to be perfect though as the seatpost clamp will hide most of it.

Here are two seriously shortened frames. Each one probably took about 15 minutes.


A secondary modification of the neck has no matter in the stiffness of the whole design ratio wise ? Anyway a shorter neck in itself should be stiffer, accentuated by the seatpost being probably lower inserted in the tube. So what about the stress on weldings for example ?

Within reasonable limits, it’s absolutely fine. (at some point you will have not enough seatpost insertion). Unicycles aren’t highly engineered pieces anyway. Shorter leverage will mean less stress, any effects on stress due to the change in stiffness due to the lower inserted seatpost are likely much smaller.

The main disadvatage of having a shorter frame neck is the reduced amount of seat adjustment you can achieve with the same length seatpost. On the frames Duff has shown there is maybe 4 cm of possible adjustment, while on a standard frame it’s probably possible to adjust 20cm without needing a new seatpost.

I imagined a longer neck would “flex” before applying a critical stress on weldings and didn’t take the stretch factor in consideration I guess.

gosh how short are your legs?

I’m 185cm, but I have a swimmers build, long torso/short legs. My younger daughter on the other hand is probably on course to be 155cm or so, and that’s still a few years away. She’s 9 now and one of those is a 24x3 and the other a 26x2.35. I didn’t have to cut down the frame on the 20".

A bit annoying that kids keep growing. Sawing the saddle pins off is easy, but welding them back on is not doable when they get taller :slight_smile: Naturally you can spend money on new/second-hand unicycles later on.

I figure I have a few centimeters to adjust as it is, although finnspin is correct that it’s only a few. After that it’ll be a matter of replacing the seatposts and hopefully she doesn’t lose interest, but you know how adolescents are. Who knows how cool she’ll think unicycling with her father is when she’s a teenager.

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