Double ended inner tubes

[kylecycler]

I fitted one recently to a clubmate's leccy Kalkhoff's rear wheel. I'd helped him fix a front wheel puncture, which wasn't such an issue, but he was fretting about getting the rear wheel on and off if it punctured (he's elderly and doesn't keep so well, and it's fiddly to do on that model), so I saw these on sjs, just like iandriver, and suggested he might try them.

He got them about a week later. I was inclined to try taking the rear wheel off - found instructions for that particular Kalkhoff on YouTube (something to do with lining up an indicator as well as disconnecting the electrics, but I can't really remember) - for the sake of not cutting the existing inner tube, but we decided it wasn't worth it so just cut it.

First attempt with the double ended tube we didn't inflate it enough before fitting, so although it appeared fully inflated it kind of 'shrunk' inside the tyre, as if it had a leak (it hadn't; the ends of the tube just moved apart) so we had to try again. Second attempt was fine.

Apparently you feel a very slight 'bump' on each revolution of the tyre when riding from where the ends of the tube butt together (I didn't try it myself but that's what my pal told me), but no more or less than you feel from the road, I suppose, and he's quite happy.

One unexpected plus was that you don't even have to hold the bike up or flip it upside down to change the tube, you just lay the bike on its side and unhook one bead of the tyre. That means it's considerably easier and quicker to swap a tube on any bike, whether it's hard to get the wheel on and off or not - I guess that means they might be worth considering if you commute to work and saving time sorting a flat might save you being late.

And yes, of course you have to buy at least two tubes; my pal bought three, so if or when he gets a front wheel puncture (the Kalkhoff has Magura brakes and a front hub dynamo, so even the front wheel is fiddlier than some to get on and off), we'll do the same with it.

[iandriver]

That's very interesting. Thank you kylecycler.

I have to confess, I'm intrigued by them as much as anything else. Nice to hear a real world experience.

I'm my life of cycling, I think I've only ever had a couple of puctures so severe they couldn't be fixed. Had a couple of valves detach from the tube over the decades, so you never know.

[[XAP]Bob]

I always carry one, and have used one.

They aren’t a long term fix, they’re a “get you somewhere warm and dry” spare.
You *must* find the source of the puncture (I.e they’re great for that great big nail you just rode over), but you can tie the “normal” tube round the chai stay/seat stay to keep it out of the way, replace the tube and be off. Then at home (other erm dry places are available) you remove it, repair the “proper” inner and replace.

I can feel the ends of the tube, I think because the air gets “trapped” to the end as you roll forward.

[JohnW]

Now I have seen it all

+1 to that.............
I wasn't sure at first that it was for real, but there's logic in it.

[iandriver]

I can feel the ends of the tube, I think because the air gets “trapped” to the end as you roll forward.

That makes perfect sense.

[PH]

Might be stating the blindingly obvious, you actually need 2, one on the bike and the spare.
Few years ago one if my CTC group punctured and was quite chuffed because he had one if these tubes as a spare until someone pointed out (we thought it unlikely he had bought 2!) if he had a standard tube on the bike then the wheel gad to come out anyway. He was quite deflated !

But not at the side of the road, the original tube can just be tied out of the way.

[kylecycler]

I can feel the ends of the tube, I think because the air gets “trapped” to the end as you roll forward.

That makes perfect sense.

The ends of the tube are quite substantial 'plugs', moulded in, so that's what you feel - they don't compress the same as the rest of the tube (also, of course, there's inevitably a very slight gap that you can feel when you press the tyre with your fingers).

Might be stating the blindingly obvious, you actually need 2, one on the bike and the spare.
Few years ago one if my CTC group punctured and was quite chuffed because he had one if these tubes as a spare until someone pointed out (we thought it unlikely he had bought 2!) if he had a standard tube on the bike then the wheel gad to come out anyway. He was quite deflated !

But not at the side of the road, the original tube can just be tied out of the way.

I had to read that a couple of times but you're right, I hadn't thought it through. And I suppose you could just repair the original 'normal' tube 'in situ' when you get home - still between the seat stays or fork legs - and put it back in, if the wheel is hard to take off and on, such as on some pedelecs.

[hemo]

I use Gaadi permanently on my rear hub ebikes and carry a spare for simple replacement, I then repair the punctured tube later.
Finding the place of a puncture is no harder then then having the tyre off the bike, locate the approx. position of the puncture and carefully manipulate the tyre area inside and out to look/feel for foreign objects.
They are ideal for ebikes with hub motors or bikes with IGH.

[bungle73]

Halfords were selling split tubes ~20+ years ago. Nothing new.

[andrew_s]

Halfords were selling split tubes ~20+ years ago. Nothing new.

There's very little that's completely new - a lot of "new" ideas are taking something that didn't work before, and seeing if the problems can be overcome by newer technology.
The split tubes I remember from before had flat ends that you overlapped a few inches.

[iandriver]

The split tubes I remember from before had flat ends that you overlapped a few inches.

Now that makes me wonder if you had the sort of destruction you have from a tube bursting through a gashed sidewall if you could cut the tube, glue the ends with puncture repair glue and have it get you home with a tyre boot also.

[nirakaro]

I've heard – though I've never seen one – that these exist, so that you can replace the tube after a puncture without removing the wheel.
I've also heard – though I'm sceptical – that you can make your own by cutting a standard tube and sealing the ends. My attempts in that direction have failed dismally, with air pouring out of the sealed ends. Is it possible? Anyone done it? What's the secret?

[thirdcrank]

I've certainly seen pics and reviews, possibly CJ's stuff in the CTC mag. I toyed with the idea for a bike with a Nexus 7 spd coaster hub but never got a round tuit.

I think the key is that the ends are flat so they butt together.

[9494arnold]

Have owned one. Came with a bike and only realised what it was when it punctured.
Yes the ends are flat .
Downside is to be effective, you actually need 2 plus, one on each wheel of the bike and one spare .
Don't know about making your own. ?

[Jdsk]

Discussed here:
https://forum.cyclinguk.org/viewtopic.php?f=1&t=135175&hilit=DOUBLE+ENDED+TUBES

Jonathan