If you’re still running tubes, this Tannus Armour will give you a little more protection on the trail.
Tubes. The thing I always carry on rides, but haven’t had to use in years. I never bothered with tubeless when I lived somewhere flat, with trails made primarily of dirt. Some years ago, after moving to the rocky wastes of West Yorkshire, that lasted about a month before I and all my mountain bikes were permanently converted. This past year, even test bikes have started arriving set up tubeless rather than tubed.
I know you’re out there though: tubeless refuseniks. The Not Tubeless Ready. Hardcore rubber fanatics. You’re out there, running your 40PSI tyres and this Tannus Armour may just open up some options for you to experience the joys of lower pressures and the reduced rolling resistance they can provide off road.
Tannus Armour Specification
- Price: £29.99 per end
- Weight: 312g
“As quick and easy as fitting a regular tire” and “40 seconds”, proclaims the back of the box. In the box, you’ll find just a single piece of foam, for which you’ll need to provide your own inner tube.
The installation steps, helpfully embossed on the side of the insert, are to pump the tube up slightly, put it in the Tannus Armour, put that lot in the tyre, then mount it all on the rim at once. In my case, I also had to dry the rim and scrub sealant residue out of the tyre too.
Depending on your tyre width, you might also need to trim the insert, for which there’s a size chart on the box and cut lines printed on the insert. Kind of like the shoe size printed on some replacement insoles.
Despite the panoply of tricks I’ve learned from testing so many inserts over the past four years, at first I had a deeply terrible time fitting Tannus Armour. It was for one single reason: a 25mm internal width rim. A measurement that goes for a lot of rims and wheelsets from a few years back – while not ultra-modern in a world of 30 – 35mm internal widths, it’s still not that narrow a rim size.
I started out with a fairly burly tyre, but after this much experience fitting inserts, could tell how badly that was going to go and switched to a much more pliable 2.4in Onza Ibex. Even then, it took about 40 minutes, half a dozen zip ties, and some soapy water. Then the tyre went up very inconsistently and needed a ride round the block before the bead would seat uniformly.
Take two: an identical tyre, but with a 35mm internal width rim. Suddenly, it’s all fine and goes together easily. Not quite forty seconds, but a few minutes tops. First ride out, I realised I’d put the tyre on backwards, and not only could I remove the beads by hand, but getting the tyre off, flipping it, and reinstalling with the Tannus Armour took about four minutes, including letting the tube down and pumping it back up.
So, if you’re going to go for Tannus Armour, I’d recommend you have wide rims. Those wide-for-2014-but-not-so-much-now ones are going to be hell to work with. I cannot stress enough how easy this was with a wide rim, and what hand-wrecking nightmare fuel it was with a narrower one.
I fitted and removed this several times during the test. The last time, I tried removing and refitting leaving one tyre bead on, and sure enough, stuffing the tube and insert assembly in one piece at a time worked just as well, if not a bit faster, than fitting it as Tannus advises.
Untrimmed, these inserts came in around 312g, which is very close to their claimed weight of 310g for a 27.5in, 2.1 – 2.5 sized insert. That’s also relatively heavy compared to most tubeless inserts, which on average seem to range from 100-250g. That said, I only noticed the extra wheel weight when picking up a silly-light enduro bike that’s mostly carbon fibre.
Finding the desired pressure to pump it up to took a bit of trial and error, which I sorted out mainly by riding.
I ran this in two different bikes, both ending up around 14 – 16PSI, which I’d expect to produce instant inner tube destruction if it wasn’t tucked into a big foamy cocoon.
Beyond ones specifically designed to do things to your tyre sidewalls, standard inserts are much of a muchness when it comes to their effect on tyre damping. Most offer rim protection first and foremost, leaving a large air gap that ends up feeling a lot like a tubeless tyre without an insert. At most, they tend to offer a little more sidewall support.
Tannus Armour beefs up your sidewalls a bit, and compared to tubeless inserts does some odd inverse tyre damping too. Basically, the bulk of the foam sits just underneath the tyre tread, leaving all the air pressure at the centre. Pump 40PSI into the tube, and it crushes all the foam up against the inside of the tyre, leading to a hard feel, but still not as firm as it’d be without the foam. Drop the tube down to 14PSI, and you get a much softer tyre, but not as soft as a standard tubeless tyre setup would feel at that pressure.
Compared to standard tube or tubeless, any given difference in PSI feels smaller than it is. It’s sort of like being able to run a 2.4in tyre as if it’s a plus tyre, and I did tend to end up at similar pressures to those I’d use for 2.6 – 2.8 tyres.
If you usually do a squash test rather than using a PSI gauge, you’re absolutely going to have to recalibrate your thumbs. The cross section of the foam puts way more at the tread too, so you end up with much more give at the sidewalls than when pushing straight down into the tread. On the bike, I found this meant my sensitivity to tyre pressures was reduced.
In terms of vibration damping and comfort, these do a good job, but I didn’t find it much dissimilar to running a tubeless tyre at 17PSI with or without an insert.
Until, that is, I went too low, which was around 8 – 10 PSI. Suddenly, the tyres wallowed through corners. I rode like this for half a descent, then stopped to pump them back up a bit. The tyres didn’t roll off the rim, but they did bottom out and squidge around. No punctures though.
On removing the Tannus Armour later to check for damage, I saw it was covered in dimples on the section that goes under the tread. It seemed unlikely stones could form such sharp impressions through rubber, and indeed on closer inspection I realised all of the divots corresponded to the sealant bogeys still stuck around the inside of the tyre. Around where the insert sat above the rim, there was a crease visible all the way around the edge, but nothing else; no rips, nicks or holes.
I’m fairly impressed with Tannus Armour, but I’m not going to give up my sealant habit any time soon. Tannus Armour just doesn’t quite give the same rock-hard to super-soft tyre tuning options, but it does have a good range of adjustment. It also seems robust, though probably still wouldn’t protect paper thin XC tyres from eventually tearing.
Lack of sealant mess is nice when dealing with it, so if that’s a big issue for you, or you’ve had a traumatic incident with an exploding tyre and a mountain bike forum, this might be for you. The weight, however, is substantial: two of these inserts plus tubes come out at around a kilogram.
It works, but it’s not going to tempt me away from tubeless and tubeless inserts. In particular, that’s because of the difficulty of fitting to (by modern standards) slightly narrower rims. It also doesn’t quite open up the tyre tuning and damping options as standard tubeless with inserts that sit near the rim. If you’re a die hard tube fan and looking for something to beef them up though, Tannus Armour works and may be just the ticket.
|Price:||£29.99 per end|
|Tested:||by David Hayward for 1 month|
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