Hi all - been a while since I’ve popped in here…
I think I’m in the market for a 28" road uni (the coker just doesn’t appeal as much as i think it ought to).
Question: which is better: the nimbus 28" as sold on unicycle.uk.com; or the DM 28" ringmaster? The prices are very similar, so I need some other criterea to decide on!
Any wisdom would be appreciated.
Trevor Coultart.
Still going forwards…
Both the suppliers read this forum… 
I have a Nimbus 28 from Unicycle.uk.com. It was nicely priced, and I have always received delivery from Unicycle.uk.com within a couple of days on standard items. I bought 5 unicycles from them last year, and several sets of cranks. So I can safely say you’ll get good quick service.
The Nimbus has a basic mass-produced frame which is perfectly sound and pretty light. It has a Viscount saddle which is fair quality, but some people say they’re uncomfortable. It comes with 150mm (?) cranks, but Roger will supply an alternative at a nominal cost. I put 110s on mine ‘out of the box’ and it makes a fast, light, responsive and safe road uni.
The wheel is slim and light, and the tyre is good for fast road use. I have done 15-20 mile rides and one ride of about 30 miles with half of it being medium off road, and it stood up to it.
The Nimbus is a nice good value but basic machine. Improve it with a preferred saddle (mine has a Velo); shorter cranks (110 is widely agreed to be a sensible length for road use, unless there are lots of hills); a computer, and lights. There isn’t a lot of clearance for a knobbly tyre. The standard pedals are basic too, but they’re light and they work.
As for the DM? I’ve seen DM machines, but not a 28. I think they’re individually made to order, which means you probably get better quality, customising (bottle cage bosses? A bit of extra clearance? Choice of hubs?) but a bit of a delay. I guess that the DM is heavier, but stronger. This might be good for hard use/MUni, but overkill for road and flat trails. DM have an excellent website, and they are enthusiasts.
I doubt you could go wrong with either machine, or either supplier. I’m happy with my Nimbi (Nimbus 2, 20 inch; Nimbus 1, 24 inch; and Nimbus 1, 28 inch). I don’t think I’ve ever met a dissatisfied DM customer.
Both seem very similar to me. However there are a few gotchas when buying 28" unicycles.
The big one, DM doesn’t say if his 28" wheel is actually a 700c size. He definately used to use a funny sized 28" wheel. If that’s true, buy the Nimbus, having a 28" wheel that isn’t actually 700c size is just plain silly nowadays as all the tyre choice is for 700c. I suspect DM has moved to 700c by now though as I can’t see any reason he wouldn’t.
Also, tyre clearance. While you’re obviously wanting to buy it as a road unicycle, bear in mind that you’re likely at some point to want to put a fattish tyre on, like the schwalbe big apple or a 29" (which is the same as 700c which is usually the same as 28") off road tyre. Personally if I was to get the Nimbus I’d ask Roger to upgrade the frame to a Nimbus II frame (probably cost about £10-£15 extra) as that’s got lots of tyre clearance. If I was getting the DM I’d ask DM if it has clearance for an IRC Notos 29x2.1 which is the standard 29er tyre in the UK, or a Schwalbe Big Apple 700cx60 which is a fat coker-like road tyre. Even if you don’t think you will, if you take one ride on a big fat 700c tyre, you’re sure to be hooked and really want one.
If after asking questions you find that all things are in fact equal, both have 700c wheels, both have clearance for a big 2.1 inch or 60mm tyre, and the cost is about the same then I’d go for the DM as it has a suzue hub rather than a no-name hub, which seems to be the only difference in components.
Joe
I’m in the final stages of considering to order a Nimbus 28" with various sets of cranks. Joe sets me doubting about the fat tyre option. I intend to use the 28" on flattish hard-surfaced roads and paths only. I think for that intended use the two disadvantages of the Nimbus II / fat tyre combo are:
Any comments?
Klaas Bil
Re: 28" recommendation…
I’m in the final stages of considering to order a Nimbus 28" with
various sets of cranks. Joe sets me doubting about the fat tyre
option. I intend to use the 28" on flattish hard-surfaced roads and
paths only. I think for that intended use the two disadvantages of the
Nimbus II / fat tyre combo are:
Any comments?
Klaas Bil
Growing enough wheat for a 1-pound loaf of bread requires 2 tons of water.
Re: Re: 28" recommendation…
The extra clearance on a Nimbus 2 will NOT create extra Q factor compared to a Nimbus 1.
The frames are the same width, and the unis use the same hub. The Q factor will be identical.
The extra clearance comes from the Nimbus 1 having a traditional inverted Y shaped crown, whereas the Nimbus 2 has more of an H shape. This means that in the Nimbus 2, the tyre is moving through a square channel, and on the Nimbus 1 it is moving through a channel which is like an inverted V.
So on a Nimbus 1, you put a fat tyre in, and the tyre has a ‘taller’ as well as wider profile, and catches against the sloping bits of the fork. It gets ‘choked’.
So no problem with Q factor. Go for the Nimbus 2 as preferable to the Nimbus 1, if either (a) you want to put a fatter tyre in, or (b) you want to do ‘foot on crown’ tricks like one footed riding.
And rolling resistance? This will be influenced by three things:
I think the order of importance is pressure, tread, width. So if you put a wide smooth tyre on and run it at high pressure, there will be little difference. Of the three variables, lowering the pressure will make the most difference, because you are increasing the amount of work you have to perform in flexing the tyre walls and tread.
But (rhetorical question!) why put a fat tyre on and run it at high pressure? This would make no sense on the road. It would help in mud, although you’d be even better off lowering the pressure a bit.
On a hard surface (tarmac, concrete, compacted fine ballast, baked mud, etc.) you have a straight forward choice, then:
Hard tyre = speed and discomfort. Narrow tyre OK.
Soft tyre = slower, but a bit more comfort. Wider tyre to compensate for lower pressure, to protect rim.
Racing bicyclists run narrow tyres at ‘3 figure’ psi. That’s why they seldom sing the bass parts. ;0)
The Nimbus comes with a narrow 700 c road tyre suitable for a road touring/commuting bicycle. (It is sold as a ‘commuter’.)
I’ve found this good for 20 mile rides, and it will cope with slime and shallow mud, but not deep mud.
You can’t go wrong with a Nimbus, but if I had the choice I would go for the Nimbus 2 frame because
a) It offers more versatility for tyres.
b) It offers some scope for tricks. (Difficult on a 28 to do too much, though.)
c) Simply, it looks more businesslike.
I have a Nimbus 2 20inch. My 24 and 28 are both Nimbus 1. They’re all decent rides - and the 28 is sooooo light.
I used to agree with everything Mike says regarding tire width, pressure, tread and intended use but my recent experiences with the Schwalbe “Big Apple” tend to dispute this.
The Schwalbe catalog makes the statement that a large footprint tire has less rolling resistance than a narrow tire. They claim that the 28 x 2.35 big apple has half the rolling resistance that a “normal” 700 x 32c tire does. Therefore the Big Apple has the same rolling resistance at 2 bar as the 700 x 32c has at 4 bar! I’m not saying that I really believe this … it’s completely opposite to what I’ve always thought.
What I do know is that at 50 psi (about 3.5 bar) the Big Apple rolls exceptionally smooth, easy and quiet but is still very comfortable and soaks up bumps really well. Riding off a curb, for instance, is no problem at all. Here’s a link to the Big Apple:
The Big Apple is 1/2" larger in diameter than my 29 x 2.1 IRC Notos. Use that as a judge when determining what 28/29" frame to buy.
Steve Howard
Re: 28" recommendation…
Thanks for the comprehensive answer Mikefule. I am a
like-to-keep-all-my-options-open type of guy especially when buying
things that will last a long time. So I have decided for a Nimbus II
and will order shortly. Roger here I come.
>You can’t go wrong with a Nimbus, but if I had the choice I would go for
>the Nimbus 2
> My 24 and 28 are both Nimbus 1.
So, you didn’t have a choice then? 
>Mikefule - Roland Butter School of Catering
New job?
>My other wheel is in your mind.
>I’m surprised it fits.
Subtle. I like it. Could work as a T-shirt.
"To escape the grip of a crocodile’s jaws, push your thumbs into its eyeballs – it will let you go instantly. "
Re: 28" recommendation…
On Sun, 16 Mar 2003 11:10:56 -0600, showard
<showard.keq3z@timelimit.unicyclist.com> wrote:
>The Schwalbe catalog makes the statement that a large footprint tire has
>less rolling resistance than a narrow tire.
That is very interesting (but somewhat incredible) to me as I am in
the process of buying a 28" Nimbus uni for road use. The standard tyre
is 700c x 35 but Roger offers a 700c x 45 upgrade. I initially
dismissed that as I was looking for low rolling resistance. But this
got me thinking.
So, does anyone have a thought about which of the two tyres offered
has lower rolling resistance? Of course tyre pressure comes into the
equation but let’s say I pump them up to equal bumpiness absorption…
Isn’t making a smoking section in a restaurant like making a peeing section in a swimming pool? - George Carlin
bla bla bla alert!
Well, not to put too fine a point on it, but I think this “wider tire for lower rolling resistance” angle is a bunch of hooey. Sorry, that’s a technical term, but I’m sure you follow.
Rolling resistance (in my mind, at least) is a function of the energy lost in deforming the tire into a flat spot as it meets the road, and back to a nice round shape as it comes back up. The tire flexes as this happens, and there’s some tire scrub since the tire is forced to follow a smaller path at the flat spot. The energy is transformed into heat - it’s what makes a tire warm when you ride.
These effects are increased at lower pressures, because the flat spot is larger. The area of the flat spot is a function of the tire pressure and load (that’s you), so all things being equal lower pressure will yield more rolling resistance.
That being said, all things are not equal from tire to tire. Different tires can have lower rolling resistance by being more flexible (so they don’t mind as much being flexed). This is usually the case with high thread-count casings in the high-end tires. These tires will still have even lower rolling resistance at higher pressures, though.
Oddly enough, though, you may get less tired with lower pressures, just because you’re getting the suspension benefit of a softer ride. I think this is what convinces people that they’re doing less work on the softer tire. And lower rolling resistance can come at the price of cornering traction, but that’s another rant…
Tim
My guess is the “wider tire == less rolling resistance” is actually due to the increased mass of the tire. Doubling the width of the tire doubles the mass of the tire, and this added mass is at the extreme edge of the wheel, where it will increase the rolling inertia the most.
-Jon
Re: Re: 28" recommendation…
from jobst brandt, bicycle science guy,
So, larger tyres made from the same material should have lower rolling resistance. But normally big tyres don’t because they’re made out of thicker stuff.
See
http://draco.acs.uci.edu/rbfaq/FAQ/8b.14.html
So, basically they’re telling the truth, kind of.
I definately go faster on a 29" with a fat tyre on anything other than a perfectly flat track or inside a hall, because the extra bump rollyoverness lets you push the speed a lot closer to your control limits. On a long road ride a fat tyre is a really good thing.
36" Cokers with big fat tyres are usually rather faster than 40" plus big wheels with thin very hard tyres, possibly for similar reasons.
Joe
Joe – Thanks for the link! I didn’t know about that FAQ.
Re: 28" recommendation…
On Mon, 17 Mar 2003 22:53:36 GMT,
klaasbil_remove_the_spamkiller_@xs4all.nl (Klaas Bil) wrote:
>So, does anyone have a thought about which of the two tyres offered
>has lower rolling resistance? Of course tyre pressure comes into the
>equation but let’s say I pump them up to equal bumpiness absorption…
Hmm, I’ll answer myself here. I have Googled somewhat on wide tires
and rolling resistance, and surprise surprise! Most of the evidence
points indeed towards wider tyres having lower rolling resistance
(everything else being equal). The fact that many people (including
myself until recently) are misguided about this seems to come from the
following:
Wider tyres are often knobblier tyres, and the more tread pattern
there is on the tyre surface, the higher the rolling resistance.
Smooth-patterned tyres are better, slick tyres are best for low
rolling resistance.
Wider tyres have higher aerodynamical drag. This is not very
important for unicyclists, but it is the main reason that racing
bicycles have skinny tyres.
Wider tyres tend te be inflated to lower pressures. Low pressure
means more deforming, hence higher rolling resistance.
All of the above applies to tyres that have a round cross section,
such as typical bike and unicycle tyres. For car and truck tyres which
have a squarer cross section and hence different deforming behaviour,
my Googling revealed a mixed bag of evidence.
Now the sad fact is that Roger is out of stock on the wide 700c tyres
and can’t get them currently. 
http://www.bicycleclassics.com/tires.html says:
Special Note on Tire Width
Not everyone may realize it, but wider tires by nature have lower
rolling resistance than narrow ones. Imagine a wide tire and a narrow
tire each at the same pressure. Each would have the same contact
patch area, but the narrow tire has its contact patch covering a
greater percentage of the tire’s circumferance. As a tire resists
being flatened more along its circumference than its width, the
constant flattening at the contact patch faces more resistance with a
narrow tire.
Some folks while accepting this logic mistakenly argue that this
comparison is wrong. They claim this because narrow tires are
optimally run at a higher pressure than narrow ones - and that is
true! But what is also true is that it is possible to have a wide tire
at low pressure provide the same rolling resistance as a narrow tire
at higher pressure. You can have the same rolling resistance and
greater comfort and stability. This is why the wide Clement Del Mundo
fat boy tubulars were so amazingly fast!
Now, many wider tires tend to be made of heavier casings which kills
the advantages of the greater width - so don’t let low quality wider
tires scare you away from the high quality wider ones. Also, wider
tires feel like they handle slower, but gosh they feel great in hard
corners! Plus, wider tires are great of you hit the occasional dirt
road!
http://www.recumbentcyclistnews.com/pages/sample12.html says:
http://fancycarol.free.fr/car_data_html/result8.htm says (in a caption
to a graph):
http://www.ultracycling.com/equipment/tyres.html says:
Never play leapfrog with a unicorn.
If you’re getting a NimbusII frame get a big apple 700c from any schwalbe selling bike shop. That should be most bike shops in the Netherlands. If they can’t get you it, mail order one from Germany.
Joe
This is a bizarre amount of discussion to have followed my simple little question.
:o)
Re: 28" recommendation…
On Wed, 19 Mar 2003 02:29:24 -0600, joemarshall
<joemarshall.kj4t2@timelimit.unicyclist.com> wrote:
>If you’re getting a NimbusII frame get a big apple 700c from any
>schwalbe selling bike shop. That should be most bike shops in the
>Netherlands. If they can’t get you it, mail order one from Germany.
Joe, thanks to your posts (also in earlier threads) and some googling
on the big apple I have decided I want a Big Apple on it.
Unfortunately, Roger sells the Nimbus II only with the standard skinny
700c x 35, no 700c x 45, no Big Apple and no nothing (this was not a
pleonasm). So the plan is to ride it with the skinny tyre for some
time and then replace it with a Big Apple - that way I can experience
the difference myself too.
I just ordered! Yahoo!
Carpe Noctum. Anything worth doing happens after dark.
Re: 28" recommendation…
Klaas Bil wrote:
>
> I just ordered! Yahoo!
Hi Klaas,
Congratulations! Now you can start experimenting with different crank
lengths and tire pressures. Maybe someday you can crank it up a notch
with one Harper’s epicyclic hubs! Although, I can’t quite picture your
hair blowing wildly behind you as his does in his videos.
Cheers,
Jason