I wonder if the more rounded profile is always a good thing. It is true that a more rounded profile will be less effected by road camber. However, it also follows that this more rounded tire will also make it harder to make smooth turns by just leaning into the turn. It would also seem to follow that a more rounded tire would make it harder to ride with two hands on a handle, especially at slower speeds.
The effect of camber and the effect of leaning into a turn are exactly the same thing. The tuning effect caused by road camber on more square tires is a bad thing and this very same effect is a good thing for leaning into a turn and making smooth turns on hard surfaces. In the end I guess it is up to the rider to determine what kind of tire they want based on the type of riding they do.
I measured the aero rim this evening. Bead seat diameter is 785mm. The tyre is designed for a bead seat diameter of 787mm. So the old aero rim is 2mm down. Not sure if that is significant. The sidewall of the rim to the bead seat is 7.0mm deep. The rim outer diameter is 799mm. Does anybody have the measurement for a new Nimbus Rim?
The rim is 30mm wide. The new Nimbus rim is 42mm wide.
When inflated to 32psi the TA tyre is 907mm in diameter. Not sure what the new tyre is when inflated as I donāt want to put it back on.
The bead seat witness on the TA tyre is 7mm deep, so the tyre fits the rim nicely.
Has anybody fitted the old Nimbus Nightrider tyre to the aero rim?
I thought I said it in my review but I didnāt : I ride 99.9% of the time with both hands on the handlebar.
Since I made a DIY handlebar that allows me to put my hands close to the seat or far away from it, and since I often change from one position to the other, I can tell that during this test ride, I did find my G36 easier to ride (holding it with both hands) than with the previous tire that was a KG, including at slower speeds.
I have only had one ride with it, so itās not much, but during this ride I only felt positive things. I only found improvements over my previous tire.
Like I did say on my review, maneuverability has been improved.
I will focus on what you say during my next ride though.
Roger said in his post nimbus quax and ta all were made in the same factory using the same carcass and bead and bath , if the new carcass and bead in the light weight tire is not compatible with a 32mm rim will the carcass and bead be different in the other tires to make them work on a 32mm rim or are there other factors .
I am assuming that Fat D is referring to the undersized Airfoil rims that were sold in the mid-2000s. I had one, Iāve had a TA blow off at modest pressure, Iām not surprised another tire blew off at 55 PSI, no-mater how it is constructed.
The issue is not the width of the rim, itās a smaller hoop. At the time the Wheelman TA tire was the only suggested tire for that rim as the others would blow off. I donāt know how many of these rims are still being used but it canāt be that many. Fat Dās experience is a good data point, but for anyone who does not have an Airfoil rim I would not worry about it.
Itās good to see some lighter options coming to market.
EDIT:
I have not tried a Nightrider on my airfoil rim, but can tell you that when I put the old TA that blew off my Airfoil onto a Nimbus Stealth rim it was tighter than the Nightrider that came off. I think pretty much anything else will be loose and prone to blowing out on that rim.
I donāt believe that is so. Tyres donāt come any more rounded in profile than the Hookworm and they are terrible on camber.
Pliability of the sidewall is a much more important factor for camber. The Hookworm doesnāt even have a sidewall as such and this is why it is so dreadful at any reasonable pressure. You have to pump them so hard that they virtually have a point contact to make the camber thrust manageable.
If I understand correctly, the Nightrider Lite has a much more flexible carcass than the original so I would expect it to be better on camber.
Thatās right, considering the softness of the sidewall I was expecting to fit it easily with only my hands, even if fitting a 36er tire with a 29er tube is always more complicated than with a 36" tube.
I tried and tried, I even warmed the tire with a hairdryer, but eventually I used levers, but that was plastic levers, and fortunately I managed to fit it without damaging the tube, (it was inflated a bit).
Compared to other bulkier or harder tires, like the TA (If I remember well) or the Maxxis Hookworm 29"&26"(Iām sure about this one) it was easier since I didnāt have to use metal levers.
It was just not as a piece of cake as it can be with a schwalbe supermoto or a surly knard.
It took me an hour and a lot of sweat to remove the wheel, remove the previous tire, talc the crape out of the tube and the new tire, to install the āLiteā tire and to reinstall the wheel on the uni (itās a geared wheel, loctite is needed on the bearing holders bolts) .
So no, the beads are not as weak as they look like.
That would be interesting to know if Fat D struggled to fit the Lite tire on his rim.
saskatchewanian : you bring back hope.
Edit:
Another factor is the diameter of the section.
Hookworm (26 ans 29,) has a 2.5", and yes it is horrible on camber, the 29" being worst than the 26".
You also find a camber sensitivity with the Big Apple 29x2.35" but this sensitivity to camber disappears with the B.A 29x2"
I also have a knard 26x3 and 29x3, both 120 TPI, so very soft sidewalls. they are round but big, so they are sensitive to camber.
But I admit itās better than the Hookworm.
My very first tire was a Kenda Nevegal 26x2.7, very squared profile, and it was a pain in the ass in term of sensitivity to camber.
So I believe the best is to have a thin and round tire profile.
I donāt know if the Nightrider Lite was able to deform it self while I was riding, it was inflated to 52PSI, not the 65 PSI max though, itās hard to say.
What I just know is that I never struggled against any camber issue during this test ride, not once, and this miracle never happened during the 800 km I have ridden with this G36.
But the previous tire was not a Nightrider tire.
So itās not a comparison between the previous and the new version.
The previous nightrider tire is on my other uni, but this is a completely different 36er.
OneTrackMind,
Thanks for your observations on tires that are or are not impacted by road camber. Based on most everything Iāve read on this forum most folks seem to say that the tire shape and maybe tire pressure are the main factors but it sounds like more things come into play. I wonder if there is some kind of happy medium ground when it comes to how a tire reacts to road camber. In my experience my very rounded Coker non-skid tire is not affected by road camber at all and does not turn at all by just leaning into a turn. I have to air swim around corners. On the other hand I rode a 36er with a Nimbus Nightrider tire the other day and I could effortlessly make smooth turns by just leaning into the turn. The Nimbus Nightrider is reported to act badly on cambered roads and that makes sense. If the new Nightrider Lite tire is better on camber then it also follows that it is poorer at making smooth turns.
The sideways forces on a tyre at a angle to the road surface is caused by the contact patch being forced into a straight line in the direction of travel instead of following the leaning circle around the axle.
The magnitude of this force is affected by resistance to the tread being forced into a straight line on the road. This is called the camber stiffness. Hence tyres with stiff carcasses have a stronger thrust because the forces to flex them are greater. Treads which allow individual blocks to flex independently of the carcass distort more easily and have less camber thrust. The monolithic nature of the tread on the Hookworm is the main reason it is so badly affected by camber.
A longer contact patch results in more distortion of the tyre. A wider contact patch engages more with the carcass. Consequently higher pressures reduce camber thrust by reducing both the width and length of the contact patch.
A squarer profile meets the road surface sooner in a lean resulting in a longer wider contact patch. More importantly, the distortion from initial at the edge of the contact patch is significantly greater.
Then it gets really complicated. The camber thrust acts differently in front of and behind the steering axis. In front of the steering axis the camber thrust tends to force the wheel harder into a turn. Behind the steering axis it works against the turn. (So far I have only really come to terms with the camber thrust in in turns and extrapolated to road camber.)
In a conventional steering geometry, the steering axis is easily defined by the kin-pin axis or the line thorough the upper and lower ball joints or, in a McPherson Strut, the top of the strut and the ball joint.
On a unicycle the steering axis is not at all well defined. The upper end of the axis is somewhere on the saddle. The lower end is an ill-defined ever shifting struggle between the contact patch and the pedals. It is made even more complex by the pedals being in constant motion, laterally offset from the the primary axis and the transferring back and forth. The geometry of the rider is also involved.
In simplistic terms the relationship between the contact patch and the steering axis can be adjusted fore and aft by the rider leaning forward or back. Leaning the body forwards causes the the uni to lean backwards moving the contact patch further behind the steering axis. This is why the rider leaning forward reduces the effect of camber.
The wikipedia pages on bicycle geometry and camber thrust and are good places to start to get a grasp on the fundamentals but as far as I know, nobody has even begun to properly analyse the forces involved in unicycle steering geometry. It is just so complex.
It would be an excellent project for a group of engineering and human movement students as it would require a considerable amount of mechanical analysis on top of fitting a unicycle with several multi-directional force sensors on the pedals and distributed across the saddle plus recording the body positions of the rider like they do when preparing animations based on human movements. It would be an incredible multidisciplinary project.
No other vehicle has anything like the complexities and dynamics found in a unicycle. One night I had a lengthy discussion about unicycle dynamics with a family friend who has decades of motorcycle development and racing experience. What he doesnāt know about motorcycle dynamics and geometry doesnāt need to known. He had even built a motorcycle with an adjustable steering head that allowed him to change the rake between two positions to get a better feel for how it affected the dynamics. The morning after our discussion he told me that thinking about unicycle steering geometry after he had gone to bed had completely blown his mind.
Yep itās in the pipeline. Roger rode it and said itās insanely amazing. From what I understand, the first batch was small and all the tires were set aside to go on new unis. The light 32" tire will be available separately once thereās been more produced.
So the TA tire on a Aero rim inflated at 32 is 907mm = 35.71 inches.
In high gear would give me (907/25.4)x(17/11) = 55.186 inches
The NR (previous version) and the KG : I donāt know but I think they are around 36" = 914.4 mm, at least this is what I programmed on my cyclometer which gives me a 36x17/11 = 55.6363 inch wheel in high gear.
I measured again this NR Lite at 52PSI and it is about[B] 921mm = 36.259 "which in high gear is (921/25.4)x(17/11) = 56.038 inches wheel
To resume:
Low Gear:
TAā¦35.71"
NRā¦36" (to be verified)
NR Liteā¦36.26"
High Gear: (x 17/11)
TAā¦55.19"
NRā¦55.64"
NR Liteā¦56.04"
For the posterity, I post here a copy past of my āsecond rideā review.
Iād be interested in reviews from others to compare our experience.
Iām not a high level rider, donāt do any competition, and donāt go at crazy speeds nor donāt do any crazy distance rides.
Now the review #2
Second ride with the Nightrider Lite tire on the G36.
The first ride one week ago was windy and cold, but this one was WINDY ! (and wetter)
This 23km loop was also way more technical than the first one.
More downhills and uphills, more mixed floors, alternation between soft, sandy or muddy soils and degraded bitumen, paths, cambered and bumpy sidewalks, or complicated situations in the city, with cars on the road and walkers on the sidewalks.
So,this was a harder and more complicated ride than the previous one, but still, I can confirm that this new tire makes the G36 simpler to handle.
Once again I found it noticeably easier to freemount and to move my right foot on the pedal while Iām hopping (which I do at every single freemount).
The brutal front and side wind was tricky during the first half of this loop, shifting up was useless as I was faster in low gear than in high gear (limited to 10 mph) , and riding straight was sometimes impossible.
But during the second half I have had more opportunities to ride in high gear, even on bumpy paths/sidewalks/roads and here again I found the G36 easier to handle in high gear with this lighter and more performant tire. I put less backward pressure on the rear pedal when I have to deal with a large bump, thus I donāt fall or dismount the uni, and progressively I dare to roll over stuffs that I would have done only in low gear with the previous tire.
My feeling is that this tire contributes to make of the G36x150 a very versatile uni.
At low speed the long cranks and the lighter tire make it as easy to ride as a 29er, even when you have to slalom between people/dogs in a tinny path or a sidewalk.
At higher speed you can follow the curvature of a bend by leaning on the side while holding the handlebar with both hands, you spend less energy to accelerate or to slowdown, and when you have a long and relatively clear path/road in front of you, you can pass the high gear and just pedal quietly at 13-16 mph, without having to force as much on the pedals as if a skateboarder had clung to you without your knowledge.
I also have been attentive to what happened when I was trying to make a tight turn at low speed by leaning on the side while holding the handlebar with both hands.
Since I find this tire less sensitive to camber than my previous tire, according to someone (Jim T, OneTrackMind this is for you ) on the forum it is supposed to make the turns I just talked about harder.
But I didnāt feel anything like this in this ride.
The only issue I have during this ride, and it happened quite often: unplanned upshifts when I roll over bumps or down a curb, or this kind of situations.
This is due to the polystyrene half sphĆØres I put in my fivetens to make shifting easier, this and my duck feet : they catch the button on the landing.
But the good news : I didnāt had a single UPD because of this.
This tire seems to make accidental upshifts easier to manage.
So, Iām still quite happy with this new tire.
(and no I donāt work for UDC )
Pascal
Are there any reasons to keep the old Nigthrider tyre around, or will it be discontinued? Will new unicycles be sold with the light tyre in the (near) future?
I can think of several reasons to keep the older ānormalā weight tire, including:
Lower cost
The normal weight tire fits on more rims. It has been reported that the light tire blew off one rim.
The greater rolling momentum of a heavier tire is better for riding over dips and bumps.
The more weight, the more gyroscopic effect the wheel has and that makes it easier to ride at speed.
Even though it adds a very slight amount of weight to the total rider/unicycle weight, I would think that the added flywheel effect to keep the wheel rolling between power strokes would be a benefit on really steep up hill pulls.
In the end I guess it is up to the rider, faster acceleration of the lighter tire or the advantages listed above.
About uphill, here is a copy of my 3rd ride report.
Youāll find the answer about "does it ride steep uphills better? " in it.
My wheel, including the cranks and the peddals, weights about 5200 grams if I remember well, which is more than 10 times the amount of saved rotational weight, so I donāt think the new tire is so light that the bad sides you are talking about can really arise.
But about the steep uphill, like I said on the 3rd review, it is noticeably easier to ride them.
Also, since I manage ride in high gear in more awkward places with this tire than what I was able to do with the previous tire, Iād say that it is not lighter enough to be less effective on bumps and holes, but itās lighter enough to make the pedal stroke easier to transfer to the tire and so the bump and holes are indeed easier to manage.
This is especially noticeable in high gear.
The review:
[I]
.3rd Ride with the NR Lite tire on the G36.
43km (twice longer than the two previous rides).
Tried a higher pressure, 4 bars = 58 PSI instead of 52 PSI.
The tire behavior was a step closer to a penny farthing tire in term of direction , I also felt a bit too much the floor irregularities, and the gain in term of rolling resistance was not noticeable because of a front wind during the first half of the ride.
When I reached the wet sand/muddy trail that surrounds a lake I decided to go down to 50 PSI.
That was better in term of confort, and thatās where I saw the print this tire lets on the soft floors : only 1 inch large!
This is an additional clue that this tire is rounder than the previous one.
Rounder and taller, there is only 3 millimeters of clearance between the top of the tire and the bottom of my kh frame crown (2015).
When the mud is deep and compact, it quickly gets agglomerated around the crown and between the tire and the crown.
I think it will get better when the rubber hair of the tire wears out.
There is something I discovered during this ride: I managed to climb a section that was way steeper than what I would be able to climb on the same 36er with my previous tire.
That surprised me. Thatās one of the situations in which you really feel that the wheel is 400gm lighter than before.
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