Plus every time you accelerate or decelerate.
I just might have to try it! Would I just use a regular 29er mtb tube, or is there one that you guys like best? And what is the difference in weight between the 29er and 36er tubes?
Does one’s own body weight, including what is carried in your camelbak, contribute to the difference in the “feel” of the uni, or is it only the weight in the actual wheel that makes the uni feel lighter and more responsive?
Also, if you want to save the most weight, why not go all the way, and go tubeless? What would be your reasons for and against that option. Thanks!.
I use the schwalbe 29-er tubes. The weight savings is pretty good if you’re coming off a UDC 36-er. As far as going tubeless, I have thought about it and may when I get my 29-er road uni built in case it’s out of commission for a while.
I’ve been reading about tubeless “pros & cons” on some mtb sites, and what seems to be a common theme is something like: "The additional special rim strip and the guck weighs just as much as a tube. The main benefit is the ability to run lower tire pressures."
Also, if the 29er tube does flat, is it more likely to blow out form catastrophic failure, or just get a pin hole leak like a normal size tube? If it does blow out to the point that it’s not repairable, would you have been carrying a spare tube with you in case of that happening?
My old coker tube weighs 484 gram and my 47x622 tube 247 gram. The Kenda tube I got with my KH 29er weighs 282 g. The lightest 29"-tube I had was 207 gram. My standard rim tape is made from rubber (53 gram) and that is also something that you can save some weight on by using something thinner. But there is no need for you to get on a diet, Terry. We are speaking of rotating weight. The further towards the outside perimeter of the wheel, the more noticeably. Tubeless ore 29er tube? What I can recall from previous discussions on the subject the weight will become more or less the same.
So when you are out riding, do you carry an extra tube, in case of a blowout, just to be prepared? Or if the tube is installed correctly, do you think the likelihood of a blow out would be no more than with a 36er tube?
For me, similar to the clipless thing, I would probably be worried about something going wrong, so I would probably want to carry an extra tube, at least until I was convinced that it was as dependable as a 36er tube, under the same conditions. 
I’m sure there are as many or more people who have not had this problem. Can give one pause though, and wonder if the weight savings are worth the risk, if there really is one at all.
There are a few different methods that I have read on installing the 29’er tubes, but in the end the likelihood of a blowout is only increased due to poor installation. I haven’t bothered with pre-stretching my tube and I haven’t had a problem yet. So, for me it might make sense to carry an extra. If your method involves pre-stretching the tube over night it might be better to carry a Coker tube as a spare.
A thorn will give you a slow leak just like it does with a coker tube. It is easy enough to carry an extra 29’er tube, and while the weight comes in at about half, the size is more like a third to a quarter the size of a 36’er tube rolled up.
The 32 feels soft and good on the road. Higher pressure makes it harder to ride fast.
corbin
Regardless which tube one choses - installing it on a 36er can give you trouble. For example on my airfoil the tyre takes a long time before it slowly creeps onto the rim properly. This would be too much work to carry out on the road side. I guess I have to walk if it pops. But I always carry a small pump in my camelbak if I get a slow leak.
Personally I think the tube (whatever the size) is living a pretty secure life in the darkness under those massive tires we’re using.
Just a week ago I wrote in another thread that I was sick and tired of wrestling with the 29er tubes, but then I realised that the ones I had chosen were not suitable. Expensive but not suitable. You have to find a fresh tube that with ease lets itself expand to at least the size of the tire. I usually pump two tubes and let them lie around (inflated) for a couple of days. It is not uncommon that one (or even both) will develop a slow leak. All in all this is some work but I certanly find it worthwile.
32 PSI sounds low ! How much do you weight Corbin ?
I’m using 3 bars (43 PSI) on the road and my weight is around 72kg
after blewing two 29" tubes on my 36 I opted for a radical solution: use a 26" tube for mtb! It is still in place after one year!
I was also thinking of trying to stretch a good quality, high volume 26er tube.
I destroyed my first 29er tube trying to fit it. I was snake biting it when I tried to seat the bead and it ending up being a patchwork of repair patches.
With the second tube I powdered the tyre and took my time. Baby steps and checking that I wasn’t catching the tube between the rim and the lever meant I could seat it first time.
I think I’m running at 55psi and the weight difference is easily noticable, and well worth the trouble.
Weight has different effects depending on where it is located. The outer part of the wheel is the most critical to performance because it is “rotational weight”. This means that the more weight there is the more work it takes to affect its momentum. If the rim/tire/tube combo is lighter the uni will be more “responsive” for this reason. If the extra weight were in the hub it would have less effect. If the extra weight were in your camelbak it would have even less effect.
As far as punctures go the 29 tube will be a little bit thinner so it could puncture a tiny bit easier but I don’t think it would cause a blowout. The tire maintains the even pressure on the tube so blowouts are usually the result of tire trouble specifically. A 36" tube may make for an easier spare but you will see how easy or hard it is to put the 29er tube on when you try it. I don’t have a 36er yet so I can’t really say.
I’ve been running Schwalbe AV19 29er tubes in my Airfoil KH36 single speed for 4 years now, several centuries and thousands of miles now and I have found a couple of things that make the 29er tube work well for me. I’ve installed several of these for friends too using this technique:
- I've never had much luck with other manufacturers 29er tubes. I just stay with the Schwalbe. It works for me.
- I never try to patch a 29er tube. Once they get a hole, I ditch the tube and install a new one.
- Its the install technique that makes it work or not. The tube pressure while you are trying to install the tire bead and get the bead to seat is really important.
- Use lots of talc powder in the tube and a little soapy water lightly applied with a sponge to the tire beads to aid in seating.
- Use a hand floor pump to inflate and take regular breaks to view both sides of the bead seating and wrestle it into place at lower presures. If the bead does not look like it is seating evenly by 30 lbs or so, retreat back down to 5-10 and do some more hand pushing and pulling to try to get it back on the rim in the right position and then try again. I've done this up down bit two or three times to get a stubborn tire to seat evenly around the rim. Ususally one side is more difficult than the other. The whole wrestling match might take 15 minutes or so.
- Once you go to full pressure, warn the family that you have an armed bomb that might explode and watch it for 24 hours. After 24 hours, it seems like most (but not all) 29er conversions are not likely to blow.
- I also have a hunch that you will avoid blowout problems by always using a fresh tire with a 29er tube conversion . . . . . I think that: swapping tires between different types fo rims is a problem as the tire takes a set from other rims and may be more likely to blow on a different rim with the added pressure/complications from a 29er tube conversion.
- I'm experimenting with running with 4 oz of slime to combat the desert cactus thorns in Tucson, AZ - but otherwise, I run without slime.
Cheers,
Brycer
Quality is important. The tube should grow evenly while pumped. If it looks anything like the one on the photo, use it for something else.
Keep in mind, before the Nightrider tire most people pumped their ties up to about 40psi, I usually ran mine around 35-37psi with my old coker and TA tires, and it was quite a nice ride.
I run the nightrider at about 55psi, but I think I am going to lower the psi for a more cushioned ride.
Interesting comments on this thread. It has been a while since I have ridden a 36er but when I did I rode with a 29" tube and the only flats I had were from pinch flats off-road.
I too agree with Corbin that a lower pressure can be much nicer. I played with pressure a bit and found that I was then most comfortable around 35 PSI. After 40 I found the wheel to feel harsher and more tiring on long rides despite the lower rolling resistance. I generally used around 25 PSI on the trails, 20 was OK but then I would start to get pinch flats.
I carried a spare 29" tube, did a few mid ride tube swaps due to punctures and never had a problem with blowouts even though I was using an undersized Airfoil rim.
I bought a new nightrider recently and installed it with my existing coker innertube. It was as tight as ever to put on, and I made sure it was seated at low pressure before inflating it up to 65, having confidence in the rating since I have owned a nightrider before. I went to show my flatmate and about a minute after inflating it, it went BOOM! and it must have crept off the rim without me noticing. It put a hole about a foot long in the innertube.
I didn’t pay enough heed to the warning about “new” tires. It is only so often you get brand new big tires and I knew to be careful but I didn’t think to be extra careful.
Since I posted in this thread I felt compelled to try the 29er tube I had lying around, and managed the wrestling match without lubricants by inflating and deflating to stretch it on and then get it out of the way to not pinch. It seemed easy but only because I had been warned about potential problems. This time I didn’t put full pressure in and started out soft how Corbin likes it.
Usually I would disagree but there was this one time when I got a puncture and it was fairly slow- I got to ride with a whole range of pressures without getting off to let air out. At first I felt like it was getting a bit more sluggish but then it felt a bit like I was bouncing along at a reasonable speed and getting extra smoothness from the soft tire cushioning the road bumps. There came a point when it started digging in to turn and I had to dismount eventually. You would know better than me anyway Corbin, being a much faster rider, so you probably know best. Unless it is a short-leg thing. 
I still like firm- I’ve put a bit more air in but have been too scared to go back to 65 with the new tire again.
The 29er tube feels nice-
I used a Cheng Shin 700x52/47 tube.
I got some spares and weighed them at the supermarket. The checkout operator put the tubes through as Yams and then cancelled them.
The Coker tube weighed 502g and the 29er was 178g.
The prices at Unicycle.co.nz are $45 for the Coker tube and $18 for the 29er tube, so you don’t want to have too many blowouts if you can help it.
I recently developed a relatively fast leak in my 29" inner tube on a 36" nightrider tire. I first noticed the tire getting mushy, and I could no longer ride with two hands on the handlebars–I need to take one hand off for added balance. Eventually the pressure got very low and I had to keep both hands out for balance–the thing was just oozing along and not tracking well at all. I gave up and started walking. I did run into a nice cyclist with a pump and got it back up to 30 psi. I managed about two miles before I was at the oozing along stage and gave up. The last four miles home I walked. 
I was surprised that at pressure below 20 psi the handling went to hell. I usually run 30-50 psi, and it is quite ridable throughout this range.
When I got home I switched back to a patched Coker inner tube. Hopefully it will hold up for a while. I did not bring along a patch kit. I have had to use oversized steel tire levers to get the tire off, and I do not want to take them with me. Unfortunately, that means I should not ride any farther from home than I am willing to walk. For those of you who do patch nightrider tires on the rode, do you have any advice?
Scott
maybe you could use a small bag to carry tools under your seat, like on a bike.if you have a handlebar it might be a problem.