# Tire pressure for 300lbs?



## Toby-BeachBiker (Jun 3, 2021)

Hello. For the first time in my life, I am running tubeless tires. I weigh 300lbs and I am riding a 29-inch hardtail. Any rough guestimate? I cannot seem to find a post discussing tire pressure for someone as heavy as me.

also, not a lot of rocks where I ride. Sandy, flowy tracks with some roots and things, but not rocky. 

Thanks in advance


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## ilmfat (Mar 10, 2007)

What is the tire width?


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## Toby-BeachBiker (Jun 3, 2021)

2.5


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## TheNip73 (Jul 28, 2009)

I’d go 35ish to start. Might be a little high, but first ride should give you an idea 

Rim width also has some impact on needed pressure.


Sent from my iPhone using Tapatalk


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## Toby-BeachBiker (Jun 3, 2021)

thank you. Rim is 30mm.


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## eb1888 (Jan 27, 2012)

You could be on a 35mm inner width rim. Pressure should be low enough so you get rim hits hitting roots then go up a couple psi. The rear will be 4-5 pounds higher than the front.
If you put a frame pump in your pack you can add pressure as needed. Then check with a gauge or by feel.
If you have 30mm inner rims the pressure will be higher.
Skinnier rims will need more pressure to keep that size tire from getting squirrelly in the corners.


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## Dawgprimo (Mar 7, 2004)

I would think some good quality strong rims would be the best for you. 
I agree with the others that a 30 - 35 mm width rim (Or even a bit wider) would get you a good wheel!
Too thin of a rim and the tire will feel wobbly or flex, like EB1888 said!

I always use a good, quality, solid rim to give me a great ride!
Cheers,
k


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## hammersorethumb (Sep 14, 2018)

SILCA Professional Pressure Calculator


SILCA has amassed what is considered by most to be the largest collection of data in the world of tire size, pressure, rider weight, and course.




info.silca.cc





here ya go.


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## uzurpator (Dec 8, 2005)

hammersorethumb said:


> SILCA Professional Pressure Calculator
> 
> 
> SILCA has amassed what is considered by most to be the largest collection of data in the world of tire size, pressure, rider weight, and course.
> ...


This calculator is funny. It gave me 19psi f/r for 75kg rider and 21psi f/r for 140kg one.

Anyhow - I ride 30/40 psi F/R on my freeride bike ( which I jump to flat and, generally speaking, mistreat ) and 25/30 F/R on my enduro rig. I weigh 240lbs + bike + gear


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## Toby-BeachBiker (Jun 3, 2021)

Thank you all for your help.


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## stiingya (Apr 30, 2004)

Toby-BeachBiker said:


> Thank you all for your help.


Below is a safer MTB calculator.






Calcolatore pressione mountain bike


Calcolatore per la corretta pressione dei pneumatici della mountain bike



mtb.ubiqyou.com





this article has the same calculator, but lots of good info.









Mountain Bike Tire Pressure Calculator + Chart – MTBS&F


Mountain bike tire pressure can be confusing. Get a free tire pressure calculator and learn tire pressure best practices like what PSI and casing to run here.




mtbskiingandfitness.com


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## Aquilon (Apr 3, 2008)

Ballpark that has always worked for me - my weight fluctuates a lot - I am currently about 260 lbs and ride at 32 front and rear. For every 10 lbs my weight changes, I will increase or decrease by about 1 psi. That said, I like a fairly firm ride (and not trashing my rims).


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## brawlo (Mar 13, 2012)

uzurpator said:


> 25/30 F/R on my enduro rig. I weigh 240lbs + bike + gear


I'm running 25/30 too on my XC rig at 300 with no problems. Roots, smaller fallen timber and small rocks are all I generally deal with.

Try going for say 30/30 and ride loops at your local with a pump handy. Keep dropping pressure a couple of psi per loop until the tyre just starts to fold a little and then bump back up a couple of psi. That's what you should run for those trails. Obviously that will then have to change for different conditions on other trails


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## ChefLeo (Sep 16, 2018)

Your tire casing will also play into how much pressure you put into your tires. Stronger casing the lower the pressure you can safely run.


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## targnik (Jan 11, 2014)

At your weight.... not knowing how you ride...
I'd be guessing 37'ish rear and 33'ish front...

I'm 245lb's and run 23-25 front and 30-32 rear.

NB, on my 29+ steed I get down to 19-20 rear and 16-17 front 

Re, rider style... If you're out for a mellow spin then subtract 2-3 psi.

If you're bombing down huge berms at the bike park add 2-3 psi.

Sent from my Asus Rog 3


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## stiingya (Apr 30, 2004)

The other thing is that Italian calculator above gives a high and low rage. For me at 270 with gear it says 29 front and 31 rear. But then the range on front is 25 to 33 and the range on back is 28 to 35.

Kind of cool... I'm using the low range without issue. (which is about 2 psi higher than what I was at prior just making it up)

ALSO... was thinking back in the day when I lived across the street from south mountain I would run 42 rear 38 front because it was the only way I could keep from getting pinch flats from all the rocks... Crazy


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## Toby-BeachBiker (Jun 3, 2021)

Thank you for all of your help. I went on another ride this morning and I seem to be most comfortable with the rear tire around 36 and the front around 32. I will keep playing with it. Thanks again.


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## Blathma (May 13, 2020)

29+ i40 rim
280lbs
Street tire 3.75" width... 27/38... Squishy but tolerable, if I want a faster ride.. 35/45

Dirt wizard tires 3"
Hard pack trails and gravel, 45/55
Loamy and soft trails, 45 FR.

I just can't do the soft squishy low pressure, not sure if it's the force I impart in pedaling or just the nature of it moving too much, don't like the wiggle.


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## mikesee (Aug 25, 2003)

Blathma said:


> 29+ i40 rim
> 280lbs
> Dirt wizard tires 3"
> Hard pack trails and gravel, 45/55
> Loamy and soft trails, 45 FR.


OH.

MY.

GOD.

I hope you come to your senses before you blow those tires off the rims at speed.


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## Blathma (May 13, 2020)

mikesee said:


> OH.
> 
> MY.
> 
> ...


I don't ride fast... Seriously.. hill climb is slow and the downhill I don't bomb run anymore. Prefer the technical rides going slow. And on the flats just cruising along.
I suppose yeah, if I was to ride fast again I'd have to drop psi.. knock on wood.. Haven't had an issue in decades of riding.


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## uzurpator (Dec 8, 2005)

I think that the issue is that at such high pressures you are not really using the tire tread, almost always riding on the center knobs. Kind of a waste of a tire.


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## Blathma (May 13, 2020)

uzurpator said:


> I think that the issue is that at such high pressures you are not really using the tire tread, almost always riding on the center knobs. Kind of a waste of a tire.


I haven't noticed that.


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## chucko58 (Aug 4, 2006)

I think @mikesee is more concerned that the rim will fail under such high pressures.


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## Cleared2land (Aug 31, 2012)

Years ago I saw an aluminum rim that had peeled off about 8 inches of bead from being over pressurized. It does happen.


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## Ironchefjon (Mar 23, 2007)

FWIW, 260 lbs geared. 30mm rims on 2.5 tires. I run 24F / 26-27 rear on maxxis EXO tires. Anything higher feels stiff and uncomfortable.


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## Dung Hopper (Jun 24, 2013)

Your tires should have the max pressure on their walls. I would start at max pressure and go lower as needed.


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## dysfunction (Aug 15, 2009)

Dung Hopper said:


> Your tires should have the max pressure on their walls. I would start at max pressure and go lower as needed.


That'd exceed the max pressure on some of my rims


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## Cleared2land (Aug 31, 2012)

Those suggested max tire pressures exceed my rim limitations.


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## mikesabino (May 20, 2021)

I know this is an old thread but I've just come to a point where I question my tyre pressures. I am around 260-265 without kit, I run my tyres 18 front/21 rear and I run 2.5wt assegai (3c maxx terra, exo) upfront and 2.4 Ardent (Exo) on the rear. I don't fee I'm hitting the rim, but then again I don't get to run high speeds in my local trails (mostly pedalling trails).

The trails I "stroll" into is pretty rocky, lose, dusty, sandy desert (



 video yesterday Dec31st) with these pressures I don't ping/deflect off of small rocks I run over BUT I seem to lose momentum really - really quick. I'm looking into getting my tyre pressures dialed, hence me in this thread.

Should I up my pressures or spend more time on the suspension setup? Calcolatore pressione mountain bike tells me I should be around 28psi upfront and 31 in the back, which to me is kind of the pressure I put in my bike when I bike on pavement on the local bike lanes here. I have yet to test this pressures on the local trails but I feel this would get me bouncing off of small rocks.

I want to get the most out of my megatower. Thanks!


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## Fuse6F (Jul 5, 2017)

mikesabino said:


> I know this is an old thread but I've just come to a point where I question my tyre pressures. I am around 260-265 without kit, I run my tyres 18 front/21 rear and I run 2.5wt assegai (3c maxx terra, exo) upfront and 2.4 Ardent (Exo) on the rear. I don't fee I'm hitting the rim, but then again I don't get to run high speeds in my local trails (mostly pedalling trails).
> 
> The trails I "stroll" into is pretty rocky, lose, dusty, sandy desert (
> 
> ...


I weight about the same and run 3.0" tires on i38 rims. I run the same pressures as well. 

riding my bike the tires deflect w mechanical grip. You know what i mean if you rock crawl. This pressure gives me great traction but the bike digs in. So you have to maintain a certain minimum speed and then the bike stays up on top off the obstacles. You just get a soft plush ride.
Diff conditions call for diff pressures. 
Imo your running way to low a pressure. With that rim tire width 

i would ride on pavement. Feel the tire drag. Then up pressures 2psi at a time till you feel that tire drag sort of disappear or stop reducing. This is your max pressure for that wheel tire combo. When you trail ride. You are adjusting pressures down to improve tire grip. But you stop lowering when there is no more improvement in grip.

my rull of thumb when looking at a rider on a tire is there should be just a little tire deflection as you sit on the bike. for trail riding

anything less is just waisting energy and increasing the chance of rim or tire damage. 
Tire inserts work to provide mechanical protection and act like volume spacers for your fork. They let you run a softer tire pressure for grip w ramp up for the hits. 

i probably would run them if i were on your wheel tire combo.


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## Toby-BeachBiker (Jun 3, 2021)

I found my sweet spot...26 in front. 29-30 rear.


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## MTB_Underdog (Jul 8, 2020)

i don't know how you guys run such low pressure. I'm 265 and any time I get below 35# in the rear I start burping the rear tirel. Hit a G out ravine, BUUURRRRPPPP. Hit a decent sized jump? BUUURRRRPPPP. Guess I need to try some wider rims.


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## Leotis Denetclaw (12 mo ago)

Good Morning,

Saw your post and thought I would like to reply. I am in the same boat and weigh close to what you weigh. In my experiences I have used different tire pressures. Initially I ran tubeless with standard tires which had a very soft side walls as a result I would run between 55 and 65 psi just to get the rims off the ground. The only problem was when I hit hard I would sometimes peel the tires of the rims and crash. Later I picked up some Maxxis 2.4 TR tires and have had different results. At this point I run 28 in the rear and 22 up front. I like everyone on this feed use wide and heavier rims (DT Swiss FR/DH rims). My Brother is the same and uses Sun RhynoLites, the extra width is an asset. I find that if you compress the tire to 2/3rds (66%) of it initial height when are on the bike then that is a good starting point. I am sure everyone has different perspectives. But should get you a starting point. These days I trail ride with occasional drops of not more than 3 feet. Hope this helps


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## Sasquatch1413 (Nov 6, 2008)

Late to the game here but wanted to chime in being a big dude that hovers between 330-350 lbs. This is a loaded quesiton dependent on tire, rim, trail, riding style, etc. I run a dual ply tire in the rear and can run 26 psi tubeless in very rocky XC trails, not a lot of fast DH though. This is with a 2.5-2.6 tire on i35 rims. Front tire is more standard and I can run 21-22 psi with a 2.5-26 tire also on i35 rims. I'm running Mazza front eMazza rear currently. 

Before I ran beefier tires I was still under 30 psi tubeless in the rear. Uusally 28-30 depending on tire/trail. I've run some fast DH runs in CO and MOAB at these presures with no ill occurences. These were still some of the heavier single ply tires with protection (TNT, GRID, etc). 

Like many people have said, tire pressure is a big deal and can change the ride characteristics by moving a couple PSI. Take a gauge with you on rides and experiment. Start high and work your way down. Change it for rockier/rootier trails vs smooth stuff. Want to ride super fast/aggresive, add a few lbs. Its a very personel/equipment dependent number.


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