Tubeless - weight and hassle?

Discuss light weight issues concerning mountain bikes & parts.

Moderator: Moderator Team

mattr
Posts: 4673
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

TimF wrote:
Tue Feb 12, 2019 5:25 pm
Just wondering with tubeless if it's worth bothering with. I use my road bike mainly and the MTB every so often. I believe this stuff dries out, so how long until you've got a wheel that's getting as heavy as a tube?
3 or 4 years. And/or ~10 refils of sealant. The sealant is only ~20% solids, the rest just evaporates. Time to dry out (per refil) is dependant on which sealant, the tyre, the environment, how much you put in to start with and so on. Anything from 3 to 6 months. My record is over a year. But they were big tyres that needed a lot of sealant to seal. So i got the advantages of low pressure and puncture resistance, but no weight savings :D
TimF wrote:
Tue Feb 12, 2019 5:25 pm
Is the performance of it worthwhile, I mean in terms of feel etc.?
I'd probably go as far to say that it's the biggest game changer in MTB since disc brakes and suspension.
TimF wrote:
Tue Feb 12, 2019 5:25 pm
For info I would typically ride on road for a while before going offroad.
Not going to make any difference.

by Weenie


bm0p700f
in the industry
Posts: 4906
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

I have run my 2.0" tyres with inserts down to 10 psi. They feel squinty then but the grip on a muddy climb is awesome.

Inserts make a rigid bike feel useable on rougher ground on a full Susser they just make it a better bike with improved handling.

Its night and day over plain tubeless which is night and day over tubes.

MikeD
Posts: 225
Joined: Thu Dec 11, 2014 9:55 pm

by MikeD

bm0p700f wrote:I have run my 2.0" tyres with inserts down to 10 psi. They feel squinty then but the grip on a muddy climb is awesome.

Inserts make a rigid bike feel useable on rougher ground on a full Susser they just make it a better bike with improved handling.

Its night and day over plain tubeless which is night and day over tubes.
Yeah sure. I can't believe inserts improve anything except pinch flat protection. Why would you want to add weight to your tires, which is the worst place to add weight on a bike?

User avatar
LeDuke
Posts: 1530
Joined: Sun Oct 07, 2012 2:39 am
Location: Front Range, CO

by LeDuke

MikeD wrote:
bm0p700f wrote:I have run my 2.0" tyres with inserts down to 10 psi. They feel squinty then but the grip on a muddy climb is awesome.

Inserts make a rigid bike feel useable on rougher ground on a full Susser they just make it a better bike with improved handling.

Its night and day over plain tubeless which is night and day over tubes.
Yeah sure. I can't believe inserts improve anything except pinch flat protection. Why would you want to add weight to your tires, which is the worst place to add weight on a bike?
Because you can run much lower pressure while more or less eliminating the possibility of rim strikes. And, you can then run lighter tires, and faster rolling tires.

But the biggest reason:

More traction.

Simply put, it allows you to achieve a faster lap time. Light weight is great, but I’m after the fastest way around the course, not the lightest bike.


Sent from my iPhone using Tapatalk

TheRich
Posts: 407
Joined: Tue Jan 01, 2019 1:36 am

by TheRich

mattr wrote:
Wed Feb 13, 2019 7:37 pm
TimF wrote:
Tue Feb 12, 2019 5:25 pm
For info I would typically ride on road for a while before going offroad.
Not going to make any difference.

Mmmm, I don't know about that. MTB tires with MTB pressure wil squirm on the road (because of the level of traction available), but most people ignore it because it doesn't matter to them. At least I do.

If you're running super low pressure and your tire isn't squirming, you're not cornering very hard. Will it ride smoother with the lower pressure allowed by rim protection, sure. But an insert isn't going to add rigity to the sidewall...it just can't, and if it did, it would ride like crap.

A lot of mountain biking is in your head, and your head is easily fooled. There's value to them for racers because it helps keep the tire on the rim so they can get to the pits, but if I get a flat, I stop and fix it because even in the races I do, there's no pit and I don't want to ruin a rim because I pay for them.

bm0p700f
in the industry
Posts: 4906
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

The problem with inserts is even shop staff don't get it. However I am quicker with them than without. On the road you don't get the lower rolling resistance obviously that you get off road where it's rougher but they don't slow you down either. The inserts that are volumous seem to work the best. They also give run flat potential. Also if you flat and can only get 10 psi in your tyre when plugged that will be rideable. 5 psi will be rideable with a plus bike.

Different tyres though respond to an insert differently. You don't even have to lower pressures.

The IRC Mythos tyres I use 29*2.1" I normally run at 22 psi. With PTN I can drop the pressures as low as 15 psi, 17 is better but at 20 psi the handling is still better. You really notice it over roots, ruts, off camber stuff. Its the side walls being firmer with the insert with the tyre turning into. Bouncy balls as it does when the pressure is jacked up.

Think of it as suspension in your tyre. I ride a full Susser and the insert still works. Rim defence is a side effect.

bm0p700f
in the industry
Posts: 4906
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

They work by essentially creating two chambers in the tyre. The air chamber at low pressure has a low spring rate and the insert has a higher spring rate. The way spring constants add in series means the air chamber dominates just keeping more of the tyre in contact with the ground. The volume of the insert though stops the tyre bottoming out and burping.

TheRich
Posts: 407
Joined: Tue Jan 01, 2019 1:36 am

by TheRich

bm0p700f wrote:
Thu Feb 14, 2019 10:01 pm
They work by essentially creating two chambers in the tyre. The air chamber at low pressure has a low spring rate and the insert has a higher spring rate. The way spring constants add in series means the air chamber dominates just keeping more of the tyre in contact with the ground. The volume of the insert though stops the tyre bottoming out and burping.
There are inserts that are separate air chambers, but these are foam. They decrease the volume of the tire but protect the rim (and the tire from the rim) as a tradeoff.

They will keep the tire on the rim and keep it from going completely flat, which is crucial in XCO racing because they just have to get to where there's a fresh wheel and tire waiting. But just because "pros do it," it doesn't automatically mean it transfers over for the reasons people wish it would, sometimes it's not for ultimate speed, it's as a fail safe measure that only applies to them.

Unless they literally take up the entire space of an inflated tire and are pretty rigid on their own (and heavy), they are going to allow the tire to squirm, a lot, if pushed in a corner at lower pressures. There's just no other way about it.

This is a full on 330g mousse for gravity racing, meaning pressure is higher because bashing through rocks is part of the game, and they're just able to drop down to normal xc tire pressure. https://www.pinkbike.com/news/mr-wolf-b ... -ride.html If you cut a tire, it still only allows the bike to be limped home, despite the size and weight.

Is that smaller 107g noodle going to do that? Those (XCO) guys aren't getting flats from thorns, they're cutting tires and sealant won't save them, so they're going with something that allows them to minimize their losses.

bm0p700f
in the industry
Posts: 4906
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

Your not understanding the physics of his it works. Try a volumous insert not Huck Norris and see.

I never shred tyres or dent rims that's what I am getting at. Still got me I am quicker. I get get traction in the mud where before I had none. I can ride faster of rough ground because the bike feels more planted. This is not about rim protection. The inserts I use for that too and do offer run flat but ride with s fkatvtyre and it will wreck the insert. Not an issue for me. I am a very ammeteur xc rider.

Before I used PTN I had pro core before that work great but a big torn punctured the inner tyre/tube. Hense I gave up with pro core. Pro core need tyres bigger than 2.0" awell 2.3" min and this is restrictive. I just ride XC on 2.1" tyres.

A bit of physics for you all.

Springs in series ad in the following way. k(t) is the total spring constant ofthe system, K(a) is the spring contant of the air, k(r) spring contant of the rubber tyre and k(i) the spring contant of the insert. The spring contant of the air and tyre to a certain extend are non linear which complicates matters

1/k(t) = 1/k(a) + 1/k(r) + 1/k(i)

or k(t) = [k(r)k(i) + k(a)k(i) + k(a)k(r)]/[k(a)k(r)k(i)]

Now it should be clear the tyre used has a big influence on the pressure that can be run.

The spring contant of the air (low pressure) is the lowest term so 1/k(a) is relatively high compared to the tyre and insert term which are lower. So for tyres with flexible casing the air term does not dominate as much as trail tyres with stiffer casings. i.e you can run lower pressures in tyres with stiffer sdiewalls then with tyres with more flexible sidewalls. that does not mean however that inserts only work best with tyres with stiff sidewalls. Thats not the case at all.

The insert is imortant. the firmer the insert the dominatant the air terms becomes. If you have a 1kg trail tyre you will need a firmer insert to run the lowest pressures.
Run flat wors best with stiffer tyres even if the insert is light and squishly like PTN as the insert term then dominates. Most occasions where you will be running flat there will be some residual air pressure even if its 5 psi. With a stiffer tyre and a an insert the air term dominates again in other words your able to ride on air and a stiff sidewall will limit the squirm.

Essentially these insert work. Come insert like crush core or the vittoria and geared more to enduro riding as they are former than PTN raceline. PTN actually have a new heavier (slightly) and firmer insert called rockline which is aimed at enduro riders and E bikes. . Schwalbe pro core is quite good as you can alter the spring rate of the inner chamber to tune the system. However I have punctured pro core with a long thorn. The firmer inserts are better suited to trail tyres and the lighter inserts are better suited to lighter tyres.

So this is a suspension system in the tyre and should be viewed as such. Sorry goet all technical but the skepticsm forced my hand.

In short inserts allow sub 20 psi on tyres where the limit is around 20 psi. Plus tyres can go even lower but am insert would allow a lighter plus tyre with lower rolling resistance.

TheRich
Posts: 407
Joined: Tue Jan 01, 2019 1:36 am

by TheRich

bm0p700f wrote:
Fri Feb 15, 2019 9:22 am
. I can ride faster of rough ground because the bike feels more planted.
This is a subjective measure to some degree. How fast you can go through the rough stuff is usually limited by how fast you want to do it, and whether or not you end up flatting, mostly the former. Some people can "bash the gnar" on an XC bike faster than most on an enduro bike, because they've built that confidence and learned the techniques for riding smoother. Although it would be hard to argue that they aren't running more on luck, they are willing to do it, and that's no small thing.

Try and go around a corner with any speed with lower pressure in a reduced volume and that tire is going to squirm, and it doesn't feel good when tires squirm. So you end up losing something that you can't get back (corner speed) and gaining something you don't actually need (although we all like) smoother rolling over rough obstacles.

Another reason where these are more applicable to XCO is that their courses are more man made, with rocks that haven't had years of erosion from the environment and usage...meaning that a tire cut is more likely, and not just a cut from rim impact, but also sidewall cuts from sliding down the side of a sharp rock. Generally, most trails and most xc courses don't have that issue, but if someone dumped a truckload of sharp rocks fresh out of the ground where you ride and flatting is somewhat typical, they may be a good last resort.

I'm not sceptical of their utility to some, it's very useful in the situation I laid out, I'm skeptical of the magical properties professed here and elsewhere.

TheRich
Posts: 407
Joined: Tue Jan 01, 2019 1:36 am

by TheRich

I'm not saying you can't like what you like, or ride what works for you personally. I ride and race on bikes that are far from the optimal choice, so I'm in no position to say what anyone needs to use. Just be honest and critical about your own equipment choices and don't blindly follow "what the pros do" without understanding the reasoning behind it.

MikeD wrote:
Thu Feb 14, 2019 4:31 pm
Why would you want to add weight to your tires, which is the worst place to add weight on a bike?
This was a big thing that stuck out about these inserts after countless comments about how this or that tire is slightly, and noticeably (yeah, sure), heavier and therefore junk. No doubt everyone's opinion on dropper posts and straight leg descending techniques is rapidly evolving as well...just like it did about 29ers.

Whether something is stupid or the best choice ever if you want to even have a chance has nothing to do with whether or not Nino is using it.

bm0p700f
in the industry
Posts: 4906
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

Therich you seem to have decided insert cant improve how the bike handles even though you never tried them. Do you think the earth is flat because all you have as evidence is other peoples pictures? probably not so why is this different.

Therefore if you have no experience of them how can you say they dont do what I or other describe them to do. Your still thinking all the mainly do is rim protection and run flat. If that was the case I would not bother. I never flat big time and never dent rims.

MikeD
Posts: 225
Joined: Thu Dec 11, 2014 9:55 pm

by MikeD

bm0p700f wrote:I have run my 2.0" tyres with inserts down to 10 psi. They feel squinty then but the grip on a muddy climb is awesome.

Inserts make a rigid bike feel useable on rougher ground on a full Susser they just make it a better bike with improved handling.

Its night and day over plain tubeless which is night and day over tubes.
Running tires at too low a pressure can ruin your tires https://janheine.wordpress.com/2016/08/ ... -pressure/

mattr
Posts: 4673
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

MikeD wrote:
Mon Feb 25, 2019 9:03 pm
Running tires at too low a pressure can ruin your tires
It's called a trade off. You want traction and lightweight tyres, the sidewalls get like that. You want to run them hard enough to not get sidewall damage. You probably won't be making it round many corners.

(And if he has sealant leaking through holes caused by damaged threads in the sidewall, god knows how the sealant will manage to seal any actual punctures.)

MikeD
Posts: 225
Joined: Thu Dec 11, 2014 9:55 pm

by MikeD

mattr wrote:
MikeD wrote:
Mon Feb 25, 2019 9:03 pm
Running tires at too low a pressure can ruin your tires
It's called a trade off. You want traction and lightweight tyres, the sidewalls get like that. You want to run them hard enough to not get sidewall damage. You probably won't be making it round many corners.

(And if he has sealant leaking through holes caused by damaged threads in the sidewall, god knows how the sealant will manage to seal any actual punctures.)
Depends on how you ride. I don't push the edge of the envelope so don't need super low pressures. I never bought into that anyway. I hate going around a corner and feel the tires squirm/fold over. If I need more traction, I'll put on a new tire with deeper, more aggressive lugs. I don't ride in sloppy conditions either. Clay mud around here is so sticky it's unrideable anyway.

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post