I finally got my front Cushcore Plus installed on the front (I am a god with sore fingers and no tyre levers left) to go with the Cushcore Pro on the back. I started wondering just how much air I could let out of my tyres so I had a look and came across this:
Spoiler alert: he went 5 seconds faster with 9 psi in his tyres.
I went out today in some wet conditions on trails that were just like a carpet of roots. After a while I was fed up sliding around everywhere and just started letting air out of my tyres until I felt like I was starting to find some grip. I didn’t have a pressure gauge with me so it was best guess and when I got home I found I was down to 12.5 psi in the front and 14 psi in the rear.
I guess there’s more grip to be had so I might experiment with going lower and also see how these pressures handle the dry.
I’m 87kg riding a 2017 Giant Trance 27.5. DT Swiss M582 (40mm inner width) with Cushcore Plus and 2.6″ Nobby Nic at the front. DT Swiss M542 (35mm inner width) with Cushcore Pro and 2.25″ Nobby Nic at the rear.
I guess you can go low as you want until you feel the tyres roll sideways in corners.
I did try CC pro front but it was too much for my thumbs. Ran 16 front.
I now run 25psi rear with Tannus tubeless but note that Cam at NSMB ran less and liked the feel. I’m totally sure he’s a way better rider than me too. Of course it’s casing dependent too.
Cam:
“As luck would have it we had a hard summer rain a few days before my first rides on Tannus Tubeless (TT) and I was able to ride them in marginal conditions. At first I started with 18 PSI rear and 16 front but this actually felt a little hard for the conditions and I dropped them to 15 and 13 which was amazing. The trails we rode were steep and technical, without high G corners, and the pressure was ample. Afterward I gave the bike to my buddies to guess how much pressure I was running and to them it felt closer to 20 PSI. Traction is impressive with TT and I could ride in the moist conditions with substantially more confidence on every surface.”
i’ve run <15psi on my downhill bike (no inserts) for long periods before. Fwiw I weigh 85kg. I’m not surprised someone smaller, with inserts, can run lower pressures.
The issue becomes the tyre rolling when compressing in berms or jumps. Inserts help with that, but don’t stop it
i’ve run <15psi on my downhill bike (no inserts) for long periods before. Fwiw I weigh 85kg. I’m not surprised someone smaller, with inserts, can run lower pressures.
When I was living 6 months of the year in the snow I built a set of 24″ wheels to run 3″ Halo Contra tyres to cope with it. In the snow I would regularly run those at <10 psi but I found it was still fine once the snow started melting. Mind you, those tyres weighted 1500g each so there was a lot of sidewall support even without inserts.
When I got the cushcores installed I figured I could drop a few psi but not go as low as I’d been able to go on the Halos. However, it seems like you can really tune them to the conditions now. If I was hitting high speed berms on hard pack I guess I would want to be closer to 20 psi but in wet steep low traction conditions it would probably be more like 10. Looking forward to seeing how they cope in the snow :)
Seems to me one of the biggest advantages of inserts is the level of tuning it opens up.
Wow I thought I was pushing it running 18fr / 22rr.
I’ve still managed to get rim dings at those pressures and they feel squirmy at anything less so I can’t see me dropping down lower than that. I am quite unforgiving on my wheels, though.
Don’t you lot who run Uber soft squishyness get tyre warping/stretching? I’m yet to try inserts, but frankly I’m 10 years later than I should be after many ££££ spent on knackered tyres..
Wow I thought I was pushing it running 18fr / 22rr
That’s my starting point as well. Tried cush-cores and I could feel the thing inside the tyre at that pressure and it gave some weird sensations as you leaned the bike over, don’t suffer much in the way of flats anyhoo, so I took ’em out.
That’s my starting point as well. Tried cush-cores and I could feel the thing inside the tyre at that pressure and it gave some weird sensations as you leaned the bike over, don’t suffer much in the way of flats anyhoo, so I took ’em out.
What rim inner width and tyre width combination was that with?
I always aim for a tyre width 1.8 times the inner rim width (I’m OK with 1.6 to 2 times the width). With that ratio rim strikes were becoming a problem at around 20-22psi. Never felt a problem with the tyres feeling squishy in the corners (but then I don’t ride a lot of hardpack high speed berms).
35mm rims, 2.6 tyres, 78kg, 15rear/13front. RIMPACT front and back. Both on my Giga and BFE. I know I’m going well when I can feel the sidewall having a moan :)
Ran the same in Molini/other rocky places and not (yet) punctured or shredded a tyre. I really like the feel of lower pressures esp on the hardtail.
That was carbon Roval Traverse with a 30mm internal and a Minion DHRII 2.3 maxterra exo+ so probs about 55-56mm? something in that range. I would add that that particular rear wheel wasn’t the strongest thing that ever there was, it would regularly loose spoke tension on the NDS over the space of a couple of hours being battered around Calderdale, so there was probs a whole lot of other things going on.
I run much higher pressures nowadays than I used to, as once I got a pressure gauge I realised the pressures I was running were crazily low (around 15 psi in 2.4 Ardents, front and rear, with no inserts; I weight 77-78kg)
I’ve probably had more punctures since running higher pressures, but I find it hard not to squirm at the idea of knowingly putting my pressures as low as I used to
When I ran a 29 x 3.0″ Minion with a Rimpact insert up front on my old Stooge, even 12 psi felt too hard
Not cushcore but rimpact inserts, on schwalbe supergravity tyres I run around 16-18psi rear and about 14psi front, I might increase that a little for Scottish water bars.
Roval Carbon Wheels with 30mm internal width and Super Trail Schwalbe tyres I am at 15 Front and 20 Rear. Before inserts I used to run 20 front and 25 rear, maybe coming up to 28PSI in the rear if going somewhere fast and rough.
Was thinking about trying 10 front and 15 rear and then working up, but never got around to it.
