Yes, not many folk on the forum in Scotland to try things out and learn from, especially face to face.
So, thanks again for trying this out.
I can’t machine myself but we have a nice new 5 axle mill at work. All I need now is to figure out what I actually need and persuade the guys to machine it for me … or give up and put this down to learning, never trust the sales blurb and run a 29er fat slick for road use.
Or buy another uni, but I have exercise the n+1 rule quite excessively for bi- and tri-cycles, and I really should give it a rest.
Thinking about it, a couple of problems come to mind with a spacer:
The first is side-to-side stiffness of the frame, even with the spacer interlocking into the existing bearing housing it would rely on the longer M5 machine screws holding the bottom housing in place to keep it all together, so you'd have to tighten these up more which may crush the actual bearing a bit. Alternatively if you know someone who can weld aluminium you could weld these into the bottom of the frame which you stiffen it all up.
The second is that the mount for the brake would be in the wrong place, and you probably want a brake with a 32" wheel.
If you can get someone to weld it though, maybe the best thing is to cut the frame above the brake mount stick a block of aluminium in (plug it into the cuts), and weld it back up.
Ah, (n+1)… I’m there just now with a new mountain bike… Interesting you’ve got trikes too, I’ve got a reasonably old Trice XL-NT, pretty fast, pretty stable and very low – kind of orthogonal to the unicycle world
Yes, I think it will have to be n+1 or some exact measurements and a US (?) sourced tyre.
Trikes, I only have one but am tinkering with electric drive and Rohloff 14 speed hub…which probably means it is going to fall off the edge of the unicycle world.
It might be worth seeing if you can contact Alan Hogan who used to post on here regularly (try a PM). I don’t know him but he is from beside Inverness and I believe imported a Walmart 32" bike basically for the wheels, so he may have some Kent tyres. It is worth checking out some of the 32" threads on here as he used to post regularly on that. You’ll also find various discussions on how to buy the Kent tyre from the manufacturer.
Here is a video he did on the 32" Nimbus tyre, you’ll see the Kent tyre he replaces on his 32"er in this:
WRT trikes/electric/Rolhoff, you’ve got just the man in Glasgow to sell you all that stuff, it’s a long time since I’ve been to his shop – a dangerous place for a wallet to go though The Rolhoff Speedhub is just a beautiful piece of engineering.
I have ordered a hatchet frame now and have a 32 hole coming,think I’m going to use a dt Swiss br710 rim,have you any experience on this rim if it’s a wise choice? Thanks
I plan to try the Hatchet in fat mode but quite liked the idea of a single frame into which I could also slot different wheels, and 32 seems much more likely to me as a beginner than 36 whilst still having some of the stability that I read about for 36ers. But maybe it would be better to get a proper large frame for this when the time comes. My n+1 instincts (aka bad habits) are full on.
Wow, those are pretty serious cutouts on that rim! I don’t have any experience with fat rims at all so I can’t really give any guidance – to be honest fatbikes didn’t exist the last time I built a wheel. Given it is DT Swiss I’m sure it will be a good choice.
I haven’t done anything more to decide on a rim for myself yet, I’m still keen on a carbon one, but as I said on the other thread, that is really more for the sake of it than anything else.
Be sure to post a picture when you get it built up.
In answer to the original question in this thread: Something Fat! So much talk here about putting larger but not-fat tires in a Hatchet frame. That’s basically a waste of a cool frame. It’s purpose is to contain a fat tire, and be kind to your knees. Keep it fat!
Also I noticed a lot of confusion from one of the people posting (probalby not recently) about why certain sizes aren’t fitting even though they “should”. Please be reminded that the only dimension on a bike/unicycle tire that can be expected to be exact is the BSD or Bead Seat Diameter.
This is usually expressed on most tires by the overall diameter, like 29". But that 29 inches isn’t the rim size, and isn’t the tire’s outside diameter (unless it’s in the width range that puts it close to 29"). It is a tire that fits that 29" rim, but the outside diameter is a function of the tire’s width. Wider widths usually also mean taller tires (projecting further outward from the rim), which is why 4" tires are much larger in diameter than they usually say on the side.
Meanwhile, the width measurement doesn’t necessarily tell you how wide the tire will be, in part because your rim might be wider or narrower than the “nominal” rim the tire is intended for. Plus, tire makers will often “fudge” their numbers for marketing purposes.
So the only way to really know the outside diameter, or inflated width of a given tire, is to pump one up and measure. Or hope someone else has, and posted those numbers. And remember rim width is still a variable. If their rim was wider than yours, your tire might sit taller, or be not so wide.
Well, yes, obviously fat in the first place.
But the “much talk” was about the option of slotting a 32" wheel into an existing frame and thus get dual use out of a cool frame.
I am not sure this is a waste of a frame - and Nimbus clearly think it is worthwhile advertising it as a potential 32". Only that it doesn’t seem to work with stock tyres. I think this was comprehensively tested by DrD in the ‘approved’ way of trying it out for real.
Regarding sizes, I would be very careful indeed with anything that goes by wheel size in inches as you suggest, John, and much prefer to go with the underlying (metric) rim size and add nominal tyre width (and assuming similar height as width) as a first approximation.
As with most things cycling, Sheldon is a fantastic source of information. Tire Sizing Systems
I finally got my hatchet put together, I picked a Surly My Other Brother Darryl rim that’s been on clearance for a long time. I wanted to go tubeless, and at the last minute decided to use a studded tire meant for my bike. The Wrathchild 4.6 doesn’t exactly go on this rim easily and you can see I do not have the tire labels lined up with the valve stem and weld (I didn’t forget just couldn’t persist through the struggle). I didn’t measure this tire, but I’m pretty sure 4.6 isn’t accurate because it looks smaller than my Bud & Lou that are marketed as 4.8. This is my first ride on a fat unicycle so I can’t compare the tire to anything else, but it feels amazing on snow and ice. It’s a bit of an adjustment because this is a new form factor for me, and I’m a bit out of shape as I haven’t been unicycling much since Thanksgiving. I’m also somewhat new to unicycling, although I did put in some miles in 2020… I don’t measure pressure but the tires on there tight and I am not worried about it burping so it’s not set up bouncy. Not sure what auto-steer feels like on a unicycle but I don’t think there is any on this it’s more resistance to turning, especially on pavement, expected for a fat tire. This is kind of an extreme tire but its a hatchet right? I have other frames to put slicks on. For now I’m going downhill, maybe the 137 cranks are too short? Right now it’s -17F but maybe later today I’ll try again.
Your hatchet looks cool although not my colour but its looks great. I built a hatchet using the same rim if thats a dt swiss br 710?
I see you dont have a brake caliper on it yet so have you tried one as the spokes run close to caliper , I had to dish my rim over slightly and use a 203mm disc to get clearance.
I was drooling over the dt swiss br 710 when it came out years ago, but never got one. The rim I got is from Surly, called My Other Brother Darryl. There are a few different versions of it, and this one is for symmetrical only wheels, so it doesn’t have the 64 holes, just 32. It is the tubeless replacement for the Rolling Darryl. I’ve never used brakes on a unicycle, and haven’t tried to put a caliper on yet. It looks like there’s almost an inch of clearance between the spokes and the 160mm rotor at the top of the rotor, so hopefully that will be enough. I didn’t pay a lot of attention to dish on this wheel but I did built it in the frame so it’s probably not too far off. I didn’t imagine this would be an issue.
I have to say I’m firmly in the camp of people who think that the Hatchet looks ridiculous without a fat tyre in it. Seeing it side on like the pictures above doesn’t tell the whole story.
Yeah you can fit other wheels in such a frame (I have a 26" freewheel in a 36" QX frame right now), but it always looks a bit silly, doubly so with the extra width.
Any idea when the Nimbus Hatchet will be back in stock on unicycle.com ? I want the full 29" setup with brake but I don’t want to build it myself from parts.
The Rolhoff Speedhub is just a beautiful piece of engineering.
