My frame's done but needs some changes...

Unicycles and Equipment
1

The frame is finished but there are a few things wrong with it. I suppose I should’ve expected this given the bad luck I’ve had so far with this unicycle. Generally, I’m really happy with the way that the frame has turned out but the are a couple of little adjustments to be made and one seemingly big problem.

The big problem is that due to some sort of a misunderstanding, the legs are 72mm apart on the inside instead of being 82mm apart and fitting a 72mm tyre (the Gazz) with 5mm clearance on each side. I’m a little bit frustrated because I did write down that it should be 82mm and I’ve checked this on the copy I’ve got on my computer. I suppose I can’t get too annoyed until I find out what happened when I visit him later on today. He’s a really nice guy and he’s been very helpful with this project. He started work on the frame as soon as he could and finished it as quickly and neatly as possible. Has anyone got any suggestions about how I can fix this problem? I was thinking the I could crimp (is that the right word?) the legs a bit so they will just fit the tyre with only about 2mm clearance. Would I lose much strength by doing this? Even if I did do this, I’d be disappointed in having less clearance on the sides. Another thought I had was cutting the inside bit of the frame away a little bit and putting a plate or something on there to close it up again. I’m really not sure about this one. Would it work? I’d really appreciate any suggestions that any of you have.

The little problems are easily fixed. Firstly, the cut that he made in the top of the ‘neck’ that the seatpost fits into isn’t big enough. This will be easy and quick to fix. The other thing is that the bearing holders that the machinist made for me are a little bit too big for the bearings. They hold them in place but not as firmly as I’d like. I’ll just get Ian to shave these down to size a little bit. Once again, this be easy to do.

I also had a quick look at the range of colours that I could have on the frame if it’s done by the powder coated that Ian uses. There was an orange there but it didn’t seem bright enough. It’s hard to tell from the little sample and because the sample isn’t on metal. Could someone please tell me whether the actually paint job would turn out lighter or darker than the sample? I haven’t ordered any seat post clamps yet but that shouldn’t be a problem. ASt the moment I’m using the cheap one from my current unicycle.

It’s a shame that I have to make these changes because I was hoping to at least be able to ride my unicycle with the new frame on there. The rim and tyre won’t be here until after Christmas and after my 4 week holiday on Christmas Day.

I remeber that John Childs told me his 24" x 3" Gazz was 72mm wide at the widest point. Can someone please confirm this?

I’ve got some photos of the frame at http://www.unicyclist.com/gallery/albun59 in the ‘My Unicycles’ section. Here are the main dimensions and other details of my frame:

Top of crown to centre of axle: 355mm
Seat post bit: 150mm, 22.5mm inside diameter, 25mm outside diameter
Inside leg width: 72mm
Outside leg width: 110mm
Crown plate thickness: 6mm
Gusset thickness: 3mm
Gusset depth: 12mm on edges, 5mm at centre of arc.
Tubing size: 30mm x 17mm for main bit, 34mm x 12mm at bearing holders
Frame mass: 0.90kg = 1.98lb

Did I miss anything?

I should’ve just got a whole unicycle from unicycle.com.

Andrew Carter

(photos at http://www.unicyclist.com/gallery/albun59)

2

i say,just use a Gazz 2.6 instead for awile.it will be fatter than any tyre you’ve ever ridden anyway right?its also lighter.

then in couple months when your mind is clear,deside whether you want to crimp things.

3

A custom job? 10mm off? Disallowing the ‘wanted’ tire?

How nice can this guy be?

That sucks…have him do it over…if you have documented proof, as you say you do.

No way should you compromise for his mistake!

4

I agree with sofa, get him to redo it and to do it right. Hopefully you’ll be able to use the bearing holders off of it still, but I dont see that being a problem.

The little things like the seat post tube needing to be cut out more isnt the issue, and when your talking to him stress the fact that you cant use the tire you wanted without comprimising your design strenght. He messed up, and he should fix it free of charge. If all else fails, thats when you go for the other options, Like pintching your frame.

Chex

5

Believe me, he is a really nice guy. It wasn’t him that made the little mistake. Ian didn’t make the frame, he just planned it all with me. He said it’ll be fine to just crimp it a little bit and have about 3mm clearance each side. That’s fine with me. I wouldn’t need any more clearance than that would I?

I’ve already ordered the 3" Gazz so I’m stuck with it. Being stuck with a 3" wide tyre isn’t a bad thing though and like you said jagur, it’ll be heaps better than my current one.

I couldn’t make him redo the whole thing. It was just a little mistake and it can be fixed so I’m not going to cause any more trouble. I won’t lose too much frame strength by crimping it will I? And the frame doesn’t really need to be all that strong anyway. I’d probably consider getting the thing redone if it was being made by some big ‘faceless’ company but I’ve gotten to know Ian and I don’t want to do that to him.

I think it’ll all work out fine.

Andrew

6

3 to 4 mm clearance will be enough. I’ve got about 4 or maybe 4.5 mm clearance on my KH24 and that’s been plenty.

Having a slightly narrower frame at the crown may prove to be a good thing. It means that you will be less likely to rub your lower leg or knee on the angular edge of the crown/footrest. The paint on the outside edge of the crown on my muni is rubbed to bare metal. It’s obvious that I’m rubbing my leg (or rather Roach armor) on the frame as I ride.

As long as the crimping is done correctly I don’t see it being a problem. Hopefully the gusset won’t be in the way of the crimping.

7

Thanks John,

As you can see in the photos the gusset is pretty small and Ian said that it won’t get in the way of the crimping. I’ll try to get at least 3mm clearance out of it. Will the combination of a Gazz 3" tyre and an Alex DX-32 rim result in having the tyre sit nice and true in the rim? I’ve noticed that a lot of tyres don’t sit very nicely in their rims and it’s difficult to get them to sit true. This may be a slight problem if I don’t have much clearance.

Thanks,
Andrew

8

I haven’t tried putting a tire on the Alex rim so I don’t know how snug it is. In general the big 3" tires fit well on the rims and don’t bulge out where they shouldn’t. You should be fine with a 3-4 mm clearance on each side of the tire.

9

how much does it weigh?

10

Do you mean how much does the frame weigh? If so, it weighs 0.90kg which is about 2 pounds. My old cheap frame weighs about 0.78kg but isn’t very strong (I don’t think) and doesn’t have the flat crown. It’s also a 20" frame and my new custom one is a big 24"/small 26" frame. It’ll just fit a 26" tyre in case I want to do some touring or something. I didn’t realise this until a while ago but a big 24" tyre isn’t much ‘higher’ than a normal 26" tyre.

Andrew