Tyre inserts have gone through a bit of a phase; just few years ago they were rather popular to prevent flats and protect the rim from impacts. Their popularity seems to have dropped off as tyres have gotten better and rims have gotten stronger, but the damping characteristics they deliver remain undeniable.
Italian brand Tubolight has taken what appears to be a more scientific approach to the tyre insert game, developing an interestingly-shaped design that looks like the shell of an Armadillo. With such a unique design, we wanted to see for ourselves how the Diamana performed, so we got our hands on a few pairs and have been testing them out for the last month.
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The Diamana Theory
The theory behind the shape of the Diamana is a completely new approach to tyre inserts, and goes beyond just throwing a block of foam inside the tyre and calling it a day. Tubolight claims the shape of the Diamana inserts changes the way the air molecules move within the tyre during impact, which is where the product gets its damping characteristics from. During impact the air is momentarily trapped on the underside of the insert, allowing the tyre to have a slower and softer rebound, effectively damping the vibrations and impacts of every bump.
The shape of the insert has absolutely nothing to do with an Armadillo, but more to do with channelling air flow to the underside of the insert. The dimples take inspiration from a golf ball, and prevent air from rebounding off the surface, further aiding airflow.
For those who want to look a little deeper into the tech, the brand has published a lab report and an explainer video.
With all that theory now in your brains, now we can take a look at the claims Tubolight is making with the Diamana;
- Claim Number 1: Improved rolling efficiency by up to 9%
- Claim Number 2: 60% higher tyre pressure on the ground
- Claim Number 3: 55% higher vibration damping
Claims one and three are fairly self-explanatory, number two however needs a little deciphering. The Italian to English translation isn’t great here, and the lab report doesn’t specifically state where this claim comes from. From what we can ascertain, the slower rebound of the tyre essentially increases the contact patch of the tyre-to-surface interface, which would in turn improve traction and stability.
Tubolight Diamana Key Details
- Wheelsize | 29in or 27.5in
- Models | SL, HD or XHD
- Weight | 107g (SL 29in), 164g (HD 29in), 313g (XHD 27.5in)
- Tested Kits | Downcountry (SL Front 29in, HD Rear 29in), Super Enduro Mullet (HD Front 29in, XHD Rear 27.5in)
- Price | $199 AUD (Pair)
Riders looking for puncture protection often only run an insert in the rear, in an attempt to save weight up front. The Tubolight Diamana inserts however are only available as a pair, although as these aren’t directly targeted at puncture protection, and more at vibration damping, running them as a pair starts to make a little more sense.
We received two pairs of inserts for testing, which came in boxes labelled ‘Downcountry’ and ‘Super Enduro Mullet’. The ‘Downcountry’ kit comes with an SL insert for the front, and an HD insert for the rear, both 29in only. The ‘Super Enduro Mullet’ on the other hand comes with a 29in HD insert for the front, and a 27.5in XHD insert for the rear. Pairs of inserts are also available in matching sets, being SL/SL, HD/HD or XHD/XHD, allowing riders to pick and choose for the application.
The Downcountry kit was fitted to Nick’s Santa Cruz Tallboy, which sports 130mm of travel up front and 120mm in the rear. The SL insert weighed in at 107g, and the HD at 164g, the latter being a little more typical of what we expect for a robust insert. The thickness difference between the two was quite noticeable, with the SL being significantly leaner in construction. These were paired with a set of trusty Maxxis Forekaster tyres, in the lightweight EXO casing, and fast rolling 3C MaxxTerra compound.
The SuperEnduro Mullet set was destined for big-hitting Enduro bikes; the Santa Cruz Nomad being an obvious choice. On the scales the XHD 27.5in insert weighed in at a whopping 313g, almost twice the weight of the HD 29in insert up front. This is also considerably heavier than alternatives on the market, such as the Rimpact V2 Inserts or any of the Cushcore options. Being a big, burly Enduro bike, the Nomad was fitted with a Maxxis High Roller 3 up front, and a DHR II in the rear, both with the heavy-duty Double Down casing and sticky 3C MaxxGrip compound.
Fitting the Tubolight Diamana inserts was uneventful on both bikes, neither gave us too much grief, and there weren’t any snapped tyre levers or bloody knuckles. The inside toothed profile of the inserts definitely helps them stay put when trying to wrangle them onto the rim, and they played nicely with the Reserve Fillmore valves on both bikes.
On the trail, the inserts delivered two very different experiences between the two bikes.
When paired with the lighter-weight EXO casing tyres on the Tallboy, the Diamana SL/HD inserts had a very distinct damped feeling. Hard square-edged hits were less noticeable, and vibrations through the bike were significantly reduced. There was a noticeable boost in traction and confidence, primarily through off-cambered and rougher trails. The overall feeling was similar to that of the new Radial casing from Schwalbe, being very damped and muted.
On the Nomad however, the addition of the Diamana inserts had almost no discernible effect on the ride characteristics. The Double Down casing tyres inherently have much more damping and support compared to the lighter EXO casings, which seemed to negate any effects of the inserts.
There are the puncture and rim protection benefits of running the inserts that remain, which we didn’t have any issues with during testing on the Nomad. I did manage to bottom out the tyre on the rear of the Tallboy, potentially pushing that little bit harder thanks to the stability and traction available. At the time, it didn’t pose any issues, but later appeared to have damaged the sidewall next to the bead. It didn’t quite split the sidewall, but had damaged the carcass to the point where sealant would weep out, and slowly lose pressure over time. A OneUp bacon strip tyre plug had this sorted out, and has been holding pressure since. We’d say the split would have been much worse without the insert, rendering the tyre for the bin.
Overall, the Tubolight Diamana inserts take an interesting and more scientific approach to the problem, with some clear advantages when applied to lighter-weight casing tyres. For those on the search for a lightweight insert for XC or Trail bikes, the Diamana’s are an excellent choice and present benefits beyond puncture protection.
