follow-up
Such a big investment, haven’t pulled the trigger yet. But UDC US said they are hoping to have a batch of 27.5 Hatchet’s with 80mm rims and 4 inch tires out in April or June.
That would be great! I just got the Hatchet with a 26 inch 4.8 tire. I have been thinking of getting a second tire for the summer. I was planning on building a 27.5 by 3 (or 4). I wonder if they will sell the individual already built wheels? Or I guess I could buy the parts for a build.
32 inch tyre
I am confused; read somewhere that the Hatchet frame won’t take the 32 Nimbus nightrider tyre as it is 32x2.25 rather than the 32x2.125 given in the Hatchet spec.
Has anybody got experience with this?
According to my simple maths, the stock tyre
Maxxis Minion 26x4.8 is 102-559 in size, so 559+2112=783,
whereas the Nimbus night rider 32x2.25 is 57-686, so 686+257=800,
when the ⅛ inch smaller raiser tyre Kent 32x2.125 would be around 686+2*54=794
So, the Nimbus tyre is 6mm too big, of which 3mm would be lost frame clearance.
Given that this would be for road use, will a Nimbus tyre really not fit a Nimbus frame so that a cheap Walmart Kent tyre needs to be imported from North America to actually run a 32” wheel in a Hatchet frame?
Any advice would be much appreciated before I make a costly purchasing mistake.
Well, it’s a funny olde world… spurred on by the other current Hatchet/rim thread which we both posted on, I thought I’d better pull my finger out and stop the procrastination.
So I ordered a Hatchet frame yesterday and it came today (usual great service by UDC UK…). It also so happens I have a 32" Oracle with the stock Nimbus Nightrider tyre.
As they say, the proof of the pudding is in the eating, so I’ll take the wheel off my 32" Oracle and try it in my Hatchet frame and post a photo of the result. That should be pretty definitive.
I’ll try to get this done this weekend.
Thanks for taking the trouble; I look forward to seeing the definitive answer.
So I thought I’d best go and try this this morning before other things took over. As you can see below the 32" wheel from my Oracle nowhere near fits the Hatchet frame. It looks like it is at least 15mm from the bearing seating in the housing.
Just for completeness, this is with the tyre pumped up to 65psi (max stated pressure), just to be sure it was fully inflated.
I almost said it looks to be almost perfect, until I realised your bearings are miles away from the cups 
What a shame, I seem to remember the 32" wheels fitting the Oregon just fine (but that may have been with the Kent, not Nimbus tyre)
Thanks for the update, DrD.
I guess that also rules out a 32x2.125 tyre, which would only give 3mm more clearance.
Which sort of makes me wonder if the Nimbus Hatchet sales blurb is misleading?
You’re most welcome – I’d have felt pretty bad if you’d gone and spent a bunch of money just to find out that it was no use when it only took me 15 minutes or so to try it… and, well, there doesn’t seem to be too many of us on here from north of the border, you know how it goes :).
I was quite surprised at how far off it was, the Kent tyre would have to be pretty ‘low profile’ to fit I’d say, so much so that I can’t see it fitting.
If you really wanted to run the 32" wheel with that frame you could probably get some spacer blocks machined to sit in the frame cups , but unless you have access to some machine tools to do that yourself it would be pretty expensive.
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.
Hi DrD,
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
Parallel thread
In case anybody else is looking into this:
There’s a parallel discussion on this going on here: nimbus hatchet rim
I like the DT Swiss but only know it from my fat bike.
Thanks DrD, I’ll follow this up.
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. 
Hi m00ms
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.
They sure are impressive cut outs and sure it’ll look great once built!
I am hoping to have the rim and hub built up in the next few weeks then I can decide on tyre and brake.
Sure yes il post some photos as the build goes and likewise I’d be interested in seeing photos of yours too
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.
See, it’s as simple as that! 
Waste?!
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