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Discussion Starter · #1 ·
I'm a slightly larger than average human being at 6'2" 205 lbs. I run my 2.3's on my mountain bike at 28 rear, 23 front, so I'm no stranger to lower tire pressure. However, I've found that my gravel tires need ~45 in the front and ~65 in the rear to prevent them from flopping all over and bottoming on the rim (24mm internal). If I'm in a cross race and I'm exclusively on grass, that might be okay, but most of my "gravel" rides include a decent amount of road riding, then some gravel, maybe even some singletrack. Floppy, bottom-y tires just are no good.

The problem is that there's approximately 3 "gravel" tires that allow pressure that high. I currently run Maxxis Ramblers that I'm pretty happy with that go to 75 psi tubeless, but every now and then I'll see another company introduce a gravel tire that looks neat but then I see that the max pressure is like 50 psi.

So who the hell rides these super low pressure tires? Are 35mm/50 psi tires only for tiny riders?
 

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6’ tall, 200 lbs geared up, 700x42 WTB Resolutes at 25-30 psi on 28mm internal width carbon rims. All my rides are mixed road, gravel, trail. I’ve never owned a road bike, but I love high volume tires at lower pressures.

I tried 38’s, and they freaked me out. Too narrow.


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Higher volume tires need lower pressure to get the same feel. Road tires usually run 80-110 for 25 mm width. I run my 35 MM Gravel king SKs at about 50. And my 2.5 MTB tires run at about 30. You can't compare the pressure from one to another. Just go by feel.
But you can get a reasonable comparison with tyre tension. Pressure*width.
Your gravel tyres are equivalent to about 70psi in the road tyres.
Your MTB pressure is equivalent to about 75psi in the road tyres.
 

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Discussion Starter · #6 ·
But you can get a reasonable comparison with tyre tension. Pressure*width.
Your gravel tyres are equivalent to about 70psi in the road tyres.
Your MTB pressure is equivalent to about 75psi in the road tyres.
Exactly. And I'd never run my road tires at 70. On the 25s on my road bike I run ~80 front, 90-95 rear.

75lbs tubeless? Make sure the rim can handle that tire pressure.

I weigh about 180 and run my 37c riddlers at 40lbs, tubeless. Road, gravel, fire road, singletrack, etc.
The rims (Eastons) are good to 72psi, and I only run the rear at 65, so I think I'm good to go. Haven't had any issues with blowing off tires, but I rarely exceed the tire spec.

As for the Riddlers, I'm not sure how you do that. I had a set, they're are so floppy. I had them at their 55psi max and they were still flopping all over the place.
 

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I run my 29er 42mm Sawtooth's at 28f/30r psi normally.
Down to 26f/28r if needed.
On the 650b wheelset, the 45mm Sawtooth's were 25f/27r psi at the last race.
700c 38mm Trigger Pro's at 30f/32r.

On the roadie, the 28mm tyres usually get run at 60f/65r.
 

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6'3" 205 lbs, 24mm internal rims with 37c Riddler rear/40c Ravager front on my cross bike. Usually around 45psi rear, 40psi front. I could probably go a little lower in front but don't go lower than 42 in the rear, too many roots and such that would bend up rims.

I've never gone over 50psi in the rear, never. I ride the **** out of that poor cross bike including urban assault rides that include a lot of stair cases, offroad singletrack, racing, and anything in-between.

65psi is insanely high IMO. OP, what rims are you using and what width Ramblers? It almost sounds like your running wide tires on skinny rims. You sure your rims aren't 24mm external?
 

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So who the hell rides these super low pressure tires? Are 35mm/50 psi tires only for tiny riders?
You aren't exactly heavy, but a 35mm tire really isn't that big. Also, if you're going to be hitting singeltrack 35mm tires are a really bad choice. If you are going to ride 35mm tires, then you will need to run high pressures. Keep in mind that most pressure ratings by manufacturers are low because when running tubeless they fear you blowing the tire off the rim and suing them. Will your bike not fit larger tires? Seems like you ought to be on at least 40mm. FYI I weigh 175 and am running Hutchinson Overide 35mm tires 35psi front 45 psi rear on 21mm internal rims. I have no problems with floppiness or bottoming out, but then again if I am riding singletrack I swap 650b wheels onto my bike.
 

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Discussion Starter · #11 ·
6'3" 205 lbs, 24mm internal rims with 37c Riddler rear/40c Ravager front on my cross bike. Usually around 45psi rear, 40psi front. I could probably go a little lower in front but don't go lower than 42 in the rear, too many roots and such that would bend up rims.

I've never gone over 50psi in the rear, never. I ride the **** out of that poor cross bike including urban assault rides that include a lot of stair cases, offroad singletrack, racing, and anything in-between.

65psi is insanely high IMO. OP, what rims are you using and what width Ramblers? It almost sounds like your running wide tires on skinny rims. You sure your rims aren't 24mm external?
Hm, yeah they might be 24mm external. They're EA90 DISC wheels, which I thought used the ARC rim, but evidently that's not true.

You aren't exactly heavy, but a 35mm tire really isn't that big. Also, if you're going to be hitting singeltrack 35mm tires are a really bad choice. If you are going to ride 35mm tires, then you will need to run high pressures. Keep in mind that most pressure ratings by manufacturers are low because when running tubeless they fear you blowing the tire off the rim and suing them. Will your bike not fit larger tires? Seems like you ought to be on at least 40mm. FYI I weigh 175 and am running Hutchinson Overide 35mm tires 35psi front 45 psi rear on 21mm internal rims. I have no problems with floppiness or bottoming out, but then again if I am riding singletrack I swap 650b wheels onto my bike.
Yeah, I run 38mm ramblers, but they're really only about 36mm tires. I tried a 40mm, but it rubbed the chainstays.
 

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75lbs tubeless? Make sure the rim can handle that tire pressure.

I weigh about 180 and run my 37c riddlers at 40lbs, tubeless. Road, gravel, fire road, singletrack, etc.
I'm down to 210 from 215 and ride 700x38 Teravail Cannonballs on my Cosmic Stallion at 40 psi front, 45 psi rear. Just rode 30 miles of singletrack with rocks and roots thrown in yesterday and was remarking what a great tire and great bike.

I run the same, albeit smaller 35mm tire on my macho Man and at 35 psi, felt the front was too squirrely. At 40 psi it is much more confidence inspiring.

I'm sure I could drop the pressure a few PSI in the 38's for purely offroad riding but with road thrown in 40/45 seems to be the best.
 

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Hm, yeah they might be 24mm external. They're EA90 DISC wheels, which I thought used the ARC rim, but evidently that's not true.
Those use 17.5mm rims. They're pretty narrow, and floppy. Those wheels are really intended to be used with 23-28mm standard road tires. I mean you definitely can throw a 30+ tire on there, but you end up with what you've got. Flop.
 

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Wow! 45/65 Those pressures seem really too high to me.
I'm 165 and ride aggressively on some choppy single-track. 35 is safe and I can go as low as 32 if I use a little caution, without bottoming the tire. At your weight, I would think you could do 45/50 without issue. Ramblers are the best... but they are light with thinnish sidewalls. Pano GKs are a little beefier without getting to unreasonable.
 

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Wrong rims??? I'm 205 lbs, running Kinlin 23mm internal width rims with Teravail Cannonball 47s in 650b. Experimenting between 35-40psi. Fun tires on gravel. I've never felt anything like "floppy."

eric/fresno, ca.
 

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Discussion Starter · #16 ·
Yeah, I'd probably ride lower pressures on singletrack. As I've mentioned before, I run 23/28 on 2.3s on my mountain bike and its great on singletrack. It feels sloppy and slow on the pavement though, just like my gravel bike feels when its on pavement at only 50 psi in the rear. The problem is that I usually take my gravel bike when I'm doing a combination of road, gravel and a little bit of singletrack, and it sucks on the 45% of the ride that is pavement.

Oh and Ramblers are dead to me now. They got rid of the carbon road tubeless style bead for a regular MTB style bead, which limits pressure to 60psi. I also wonder if the casing is different, I took one of the 60psi Ramblers out and got a 1/2" slice in the tread a mile in. I couldn't find the cut on the road, so I threw a tube in, and I noticed it when I got home:
Bicycle tire Bicycle wheel rim Automotive tire Bicycle part Bicycle accessory
 
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