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Discussion Starter · #1 ·
Howdy y'all -

I have a 2018 Intense Spider 275C that I like a lot. It's pretty much stock with TLE Nobby Nics in the 2.25R and 2.35F size.

My issue is that the rear tire will "fart" or burp when going around flat corners at any pace moderate or higher. The tire also feels like it's folding over, but I can't verify that. I don't seem to be losing air pressure, so I don't think it's actually burping, but I don't know. There is no evidence of the loss of sealant, and no evidence of tire lugs hitting the stays.

Rear PSI is about 20-22, and I'm 185 lbs geared up. Suspension isn't overly stiff, and I'm getting good travel out of the shock.

What's going on here?
 

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Elitest thrill junkie
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Rear PSI is about 20-22, and I'm 185 lbs geared up. Suspension isn't overly stiff, and I'm getting good travel out of the shock.

What's going on here?
Look within for the answers. IME, that is way too low for a 27.5 tire of that volume, your weight and any kind of aggressive riding/cornering. Yep, it's going to fold over easy at that PSI. Start at 30 for the rear IMO, 27-28 for the F, but if you ride real hard you might even need a few more.

I'm lighter with about the same size tire, although this maxxis measures a real 2.25 (claimed is 2.3), I have to run significantly more rear pressure, on a wider rim, with a tougher tire, or my tire does fold over in the g-outs/berms.

On my 29er, with high volume 2.35s, I can get away with a bit less.
 

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Discussion Starter · #3 ·
Huh - weird. I don't recall these issues on my hard tail 26" bike with a tubeless setup, and I was heavier then, running similar pressure. I thought one advantage of tubeless was lower pressures and better compliance out of the tire. I'll try 30 on my next ride and report back. Thanks!
 

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Maromero
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I'm using Nobby 2.35 front, Rocket Ron 2.25 rear, on 25 mm IW CarbonFan rims, I weigh 165 lbs and run 18 to 20 psi front, 22 to 25 psi rear, no burping at all on a Flux 27.5. My guess is that 20-22 rear is a bit low for your weight
 

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Tire pressure and foldover are dependent on your rim width. The skinnier your rim the more pressure you'll need to avoid foldover.
If you've got a 30mm inner rim width you can run lower pressure than if you've got 21mm. Tell us what you've got.
 
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