Yes ..I know ..Im not new to tubeless Ive been that way on my mtb's for as long as I can remember..it was said in jest ?Unless you've got the spare tube zip-tied to your wheel, you're still benefitting.
Yes ..I know ..Im not new to tubeless Ive been that way on my mtb's for as long as I can remember..it was said in jest ?Unless you've got the spare tube zip-tied to your wheel, you're still benefitting.
I didn't really mean my reply for you - it's the internet, and you can guarantee that someone would take you literally and at face value unless they were told not to...Yes ..I know ..Im not new to tubeless Ive been that way on my mtb's for as long as I can remember..it was said in jest ?
I'm surprised at how many people don't understand one of the fundamental reasons to run tubeless and that is the weight loss. Reducing weight from your wheels reduces unsprung mass and rotational mass. Roughly speaking rotational mass is three times harder to accelerate/decelerate than srpung mass.
I think the weight gains from going tubeless are in the eye of the beholder. Biggest advantage for me over years has been the vast reduction in flat tires. My riding partners who still use tubes have had many more flats than me riding the same trails together. Couple weeks ago noticed I ran into a cactus when loading my emtb on the bike rack. Had tons of needles imbedded in sidewalls and didn't even know it. Could see residue from where sealant prevented flat. Have run sealant in my tube on my previous dh rig with mixed results. One other advantage is you can run lower psi when going all natural which provides better traction. BTW, I'm not one of those riders who push the limits on how "low" they can go on their tire psi. I have baseline settings I use based on the types of trails/conditions I am doing that particular day.I've always run tubes for ease of use, and keep considering the switch to tubeless, but not made the jump yet!
I'd like to know more about the weight difference though as I see it mentioned every so often. Any idea how much sealant you tend to use in a tire? Modern tubes weigh about 85g including the valve (Aerothan or Tubolito) and I keep thinking if you use 85ml of sealant then they will be about the same weight. I don't know what the density of the sealant is though, but assuming it is similar to water (so 85ml = 85g). And I've seen various recommendations on the web for how much sealant to use (probably from 40ml to 100+ml).
Other thoughts are that the weight of a tube is probably spread closer to the inside of the wheel - e.g. half towards the tyre outside and half towards the rim. Whereas maybe the sealant is more towards the outside of the tyre? Also if you ever top up the sealant in a tyre, then you are just increasing the weight of sealant further.
Probably because I don't ride road bikes, I have never come across a "modern tube that weighs about 85g". I looked at the weight of the tubes that came with my 29x2.6" tyres and each tube weighed 239gm. Just in case that was a super heavy "e"tube, I checked the weight of the tubes that came on my last analogue bike. The 27.5x2.2" tubes weighed 189gm each. That is a massive difference to your 85gm. If your tubes are that light I'm astonished that you are not getting flats all the time. You must be a very light and skilful rider or maybe don't ride anywhere either rocky or near spiny stuff.I've always run tubes for ease of use, and keep considering the switch to tubeless, but not made the jump yet!
I'd like to know more about the weight difference though as I see it mentioned every so often. Any idea how much sealant you tend to use in a tire? Modern tubes weigh about 85g including the valve (Aerothan or Tubolito) and I keep thinking if you use 85ml of sealant then they will be about the same weight. I don't know what the density of the sealant is though, but assuming it is similar to water (so 85ml = 85g). And I've seen various recommendations on the web for how much sealant to use (probably from 40ml to 100+ml).
Other thoughts are that the weight of a tube is probably spread closer to the inside of the wheel - e.g. half towards the tyre outside and half towards the rim. Whereas maybe the sealant is more towards the outside of the tyre? Also if you ever top up the sealant in a tyre, then you are just increasing the weight of sealant further.
Probably because I don't ride road bikes, I have never come across a "modern tube that weighs about 85g". I looked at the weight of the tubes that came with my 29x2.6" tyres and each tube weighed 239gm. Just in case that was a super heavy "e"tube, I checked the weight of the tubes that came on my last analogue bike. The 27.5x2.2" tubes weighed 189gm each. That is a massive difference to your 85gm. If your tubes are that light I'm astonished that you are not getting flats all the time. You must be a very light and skilful rider or maybe don't ride anywhere either rocky or near spiny stuff.
I don't know the density of latex sealant, I believe it floats in water, but I'll accept your assumption that 1ml = 1gm. I have 29x2.5" tyres on right now and I put 120ml of latex sealant in each tyre (the amount advised on the bottle). Less latex will work, but not as well or for as long. Any latex is better than none, for sure. That gives me a 239-120 gm weight reduction per tyre = 119g (4.2 ounces).
You are correct in your weight distribution assumptions. The mass of the tube will be equivalent to being half way between the rim and the outer diameter of the tyre. The sealant will be mostly on the outer inside surface of the tyre, but not exclusively because it does seal sidewall punctures. But let's assume that it is all at the outer.
The effect of rotating mass is felt by the square of the radius for any given speed. On a 29" tyre, the radius is 14.5", Lets assume that the centre of mass of the tube is at a radius of 13.5".
So, (14.5/13.5)squared is 1.15. The mass has an effect 15% bigger at the outer edge of the tyre than in the middle of the tyre.
But the mass of the tube is 239gm acting at the centre of the tyre (ie 1" below the outer inside face). Whereas the latex is 120gm, all at the outer; let's say the latex weighs half as much, a factor of two. That is more than enough to counter the radius effect of 15%. So even if you put a lot of sealant in, you are still better off than with a tube.
(Warning: It's a long time since I was at school, so my maths might need checking).
One of the claims made by tubeless enthusiasts is the reduced rolling resistance. It is false. It is the lower tyre pressure that leads to reduced rolling resistance because the tyre conforms to the trail rather than bouncing off it. And you can get that with tubes. On smooth surfaces of course, reduced tyre pressure will increase rolling resistance. But because the tubeless tyre no longer has a tube that is vulnerable to pinch punctures, the pressure can be lower and hence you get the reduced rolling resistance over rough trails. I read somewhere that friction between the tube and the tyre can generate rolling resistance, which may be why some riders use talcum powder between tyre and tube. But I have no idea whether this is only noticeable on high speed road bikes.
For me the biggest single benefit of going tubeless is the lack of downtime fixing punctures or changing tubes. This is particularly valuable trailside where it is normally raining or on a narrow trail where I'm blocking other riders. If I am travelling in company then I'd be holding everyone up whilst I attended to the puncture. If I was racing, I would lose many places. Whenever do punctures occur when it is convenient? In my time with tubes, I was getting one flat per 14 miles. Since going tubeless, I've had three flats in about 12 years. One was my fault because I failed to top up the sealant, the other two were defective tyres that split at the bead.
The unexpected benefit is the improved feel of the bike. Its hard to describe. It's a mix of improved grip, reduced rolling resistance and a lighter feel to the wheels. The rolling moment of inertia of the wheels is reduced and they are more responsive to acceleration, braking and turning. I used to notice this later point more on my analogue bike than I do on my emtb though.
As for your concern about the tyre becoming increasingly heavy as you top up the sealant. I guess if the tyre never gets a puncture then no sealant will ever be lost. With time though the sealant dries out and ends up (in my experience at least) either as a thin skin everywhere on the inside of the tyre and frequently as an irregular shaped ball of dried latex rumbling about inside the tyre. I throw away the ball and sometimes scrape away the skin (but mostly not). I don't see an ever increasing weight as a problem at all, because in my case it isn't increasing by anything that matters. I suspect that I lose more weight in tyre wear than I gain in dried latex.
If your tyre and wheel set up is a proper tubeless system then you don't need sealant to make it hold air (car tyres don't). But we don't fit car tyres and we do ride in places that threaten the tyres, so sealant to seal up the inevitable punctures and stop them becoming flats is a very sensible measure.
Probably because I don't ride road bikes, I have never come across a "modern tube that weighs about 85g". I looked at the weight of the tubes that came with my 29x2.6" tyres and each tube weighed 239gm. Just in case that was a super heavy "e"tube, I checked the weight of the tubes that came on my last analogue bike. The 27.5x2.2" tubes weighed 189gm each. That is a massive difference to your 85gm. If your tubes are that light I'm astonished that you are not getting flats all the time. You must be a very light and skilful rider or maybe don't ride anywhere either rocky or near spiny stuff.
I don't know the density of latex sealant, I believe it floats in water, but I'll accept your assumption that 1ml = 1gm. I have 29x2.5" tyres on right now and I put 120ml of latex sealant in each tyre (the amount advised on the bottle). Less latex will work, but not as well or for as long. Any latex is better than none, for sure. That gives me a 239-120 gm weight reduction per tyre = 119g (4.2 ounces).
You are correct in your weight distribution assumptions. The mass of the tube will be equivalent to being half way between the rim and the outer diameter of the tyre. The sealant will be mostly on the outer inside surface of the tyre, but not exclusively because it does seal sidewall punctures. But let's assume that it is all at the outer.
The effect of rotating mass is felt by the square of the radius for any given speed. On a 29" tyre, the radius is 14.5", Lets assume that the centre of mass of the tube is at a radius of 13.5".
So, (14.5/13.5)squared is 1.15. The mass has an effect 15% bigger at the outer edge of the tyre than in the middle of the tyre.
But the mass of the tube is 239gm acting at the centre of the tyre (ie 1" below the outer inside face). Whereas the latex is 120gm, all at the outer; let's say the latex weighs half as much, a factor of two. That is more than enough to counter the radius effect of 15%. So even if you put a lot of sealant in, you are still better off than with a tube.
(Warning: It's a long time since I was at school, so my maths might need checking).
One of the claims made by tubeless enthusiasts is the reduced rolling resistance. It is false. It is the lower tyre pressure that leads to reduced rolling resistance because the tyre conforms to the trail rather than bouncing off it. And you can get that with tubes. On smooth surfaces of course, reduced tyre pressure will increase rolling resistance. But because the tubeless tyre no longer has a tube that is vulnerable to pinch punctures, the pressure can be lower and hence you get the reduced rolling resistance over rough trails. I read somewhere that friction between the tube and the tyre can generate rolling resistance, which may be why some riders use talcum powder between tyre and tube. But I have no idea whether this is only noticeable on high speed road bikes.
For me the biggest single benefit of going tubeless is the lack of downtime fixing punctures or changing tubes. This is particularly valuable trailside where it is normally raining or on a narrow trail where I'm blocking other riders. If I am travelling in company then I'd be holding everyone up whilst I attended to the puncture. If I was racing, I would lose many places. Whenever do punctures occur when it is convenient? In my time with tubes, I was getting one flat per 14 miles. Since going tubeless, I've had three flats in about 12 years. One was my fault because I failed to top up the sealant, the other two were defective tyres that split at the bead.
The unexpected benefit is the improved feel of the bike. Its hard to describe. It's a mix of improved grip, reduced rolling resistance and a lighter feel to the wheels. The rolling moment of inertia of the wheels is reduced and they are more responsive to acceleration, braking and turning. I used to notice this latter point more on my analogue bike than I do on my emtb though.
As for your concern about the tyre becoming increasingly heavy as you top up the sealant. I guess if the tyre never gets a puncture then no sealant will ever be lost. With time though the sealant dries out and ends up (in my experience at least) either as a thin skin everywhere on the inside of the tyre and frequently as an irregular shaped ball of dried latex rumbling about inside the tyre. I throw away the ball and sometimes scrape away the skin (but mostly not). I don't see an ever increasing weight as a problem at all, because in my case it isn't increasing by anything that matters. I suspect that I lose more weight in tyre wear than I gain in dried latex.
If your tyre and wheel set up is a proper tubeless system then you don't need sealant to make it hold air (car tyres don't). But we don't fit car tyres and we do ride in places that threaten the tyres, so sealant to seal up the inevitable punctures and stop them becoming flats is a very sensible measure.
I do believe the claim that tubolito are in fact more straight-on (pin-type) puncture proof despite being lighter, but I would say the opposite holds true for the most common type of defect, snake-bite against bead. That is where tubeless absolutely shines.
I'm curious why you think the Tubolito's are more prone to pinch flats than regular butyl rubber tubes?
The World's largest electric mountain bike community.