Go Back  Bike Forums > Bike Forums > Fatbikes
Reload this Page >

can i put 30 pounds of air in fat bike tires

Fatbikes Designed for use in sand, mud or snow, Fat bikes are the right choice for true all-terrain riding. Check here for the latest on these fun, adventurous two-wheeled machines.

can i put 30 pounds of air in fat bike tires

Reply

Old 10-18-18, 06:03 PM
  #1  
windhchaser 
Senior Member
Thread Starter
 
Join Date: Jun 2012
Location: baned from foo so for sure im not there .
Posts: 597

Bikes: Felt nine flow

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 635 Post(s)
can i put 30 pounds of air in fat bike tires

i think it says 15 pounds or some low number that cant be correct
__________________
And the moral of the story is,
A band with no talent can easily amuse
Idiots, with a stupid, puppet show
windhchaser is offline  
Reply With Quote
Old 10-18-18, 08:35 PM
  #2  
HerrKaLeun
Senior Member
 
Join Date: Mar 2017
Location: Madison, WI
Posts: 1,071

Bikes: Giant Toughroad SLR1 and Motobecane Sturgis NX

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 546 Post(s)
typically limited to 20 psi. riding pressure is only 3-10 psi anyway.
30 psi would be very hard.
30 psi is for MTB with 2.x tires, if even that.
HerrKaLeun is offline  
Reply With Quote
Old 10-18-18, 08:49 PM
  #3  
DeadGrandpa
Senior Member
 
DeadGrandpa's Avatar
 
Join Date: Sep 2014
Location: Carolina
Posts: 683

Bikes: Trek 1120, Santa Cruz Tallboy 3CC, Fandango DC-9 MTB tandem, Jamis Renegade Expert, Bike Friday Pocket Llama, Santana Arriva tandem, Bridgestone RB-1

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 209 Post(s)
I have a 29+ bike with 3 inch wide tires. 30 pounds gives you a bouncy ride and I don't recommend it. At 14 pounds pressure I get grip in the corners of both singletrack and forest service roads, steep inclines, whatever you can roll over from washboard to roots, chunk or whatever. 13 pounds isn't quite enough. 16 is too much.
DeadGrandpa is offline  
Reply With Quote
Old 10-19-18, 09:22 AM
  #4  
5teve
Senior Member
 
Join Date: Mar 2018
Posts: 99
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 30 Post(s)
Fat bike tires/rims are designed for much lower pressure than that. I've never run more than 10-11psi in mine. I think 30psi would very possibly damage your rims or tires.
5teve is offline  
Reply With Quote
Old 10-19-18, 09:24 AM
  #5  
GrainBrain
Senior Member
 
GrainBrain's Avatar
 
Join Date: Aug 2017
Location: Central Io-way
Posts: 884

Bikes: LeMond Zurich, Giant Talon 29er

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 453 Post(s)
Go ride your bike windy!

At about 15psi.

Post ride pictures!
GrainBrain is offline  
Reply With Quote
Old 10-23-18, 06:06 PM
  #6  
buffalo4life
Senior Member
 
Join Date: Oct 2014
Location: buffalo
Posts: 73

Bikes: 86 Trek 330 fixie, 2011 Trek 1.1, POS mb

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
I rode my fatbike on the MUP today and took the tires up to about 12 psi for making some speed!
buffalo4life is offline  
Reply With Quote
Old 10-23-18, 06:19 PM
  #7  
Shimagnolo
Senior Member
 
Shimagnolo's Avatar
 
Join Date: May 2008
Location: Zang's Spur, CO
Posts: 8,538
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1328 Post(s)
The limitation is probably to prevent damaging the rims.
The larger the tire, the greater the outward force on the rim, at the same pressure.

I was once running some 2" tires that advertised a 65psi max on the sidewall.
After breaking the second perfectly good Mavic rim, I realized that was simply too much for the rims, and settled on lower pressures.

Lengthy discussion of hoop stress here: https://www.velonews.com/2017/03/bik...buildup_433214
Shimagnolo is offline  
Reply With Quote
Old 10-23-18, 07:05 PM
  #8  
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 17,065
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
forget where, probably on the FB FB group, I recently saw a blown out tire and destroyed rim at some pressure lower than 30psi. That's what I like to run in my gravel bike 38mm tires, so yeah, it's too high for a fat bike tire.
__________________
Randonneuring -- it's touring for people that aren't smart enough to stop for the night.
It's a wonderful sport when you can make up for a lack of ability with a lack of sleep
unterhausen is offline  
Reply With Quote
Old 10-23-18, 08:09 PM
  #9  
rm -rf
don't try this at home.
 
rm -rf's Avatar
 
Join Date: Jan 2006
Location: N. KY
Posts: 4,885
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 545 Post(s)
This is windhchaser's "blog", there's a ton of separate threads. Most of them in foo.

30 psi on a 5 inch tire is like 150 psi in a 25 mm road bike tire. That's extremely overinflated, enough to damage the tire and rim. Not to mention that it's terrible for comfort and handling.
See this article on "hoop stress", needed air pressure is proportional to the tire width. (like Shimagnolo posted above.)

Last edited by rm -rf; 10-23-18 at 08:14 PM.
rm -rf is offline  
Reply With Quote
Old 10-24-18, 09:05 AM
  #10  
prj71
Senior Member
 
Join Date: Jun 2015
Posts: 1,341
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 729 Post(s)
Depends on what the tire allows which is stated on the side of the tire. That varies with every manufacture and the type of tire produced.

I used my Specialized Fat Bike for a gravel race once and aired up the tires to 25 psi, which is the max stated on the sidewall.
prj71 is offline  
Reply With Quote
Old 10-25-18, 07:16 AM
  #11  
Hypno Toad
meh
 
Hypno Toad's Avatar
 
Join Date: Jul 2014
Location: Hopkins, MN
Posts: 3,377

Bikes: 17 Breezer Radar Pro; 15 Surly Pugsley; 13 Felt Z85; 11 Globe Daily; 09 Kona Dew Drop; 96 Mondonico

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 526 Post(s)
Originally Posted by windhchaser View Post
i think it says 15 pounds or some low number that cant be correct
Why do you want 30 psi?

This thread I started a couple years ago might help understand fatbike tire pressures: Fatbikes - Tire Pressure Explained in a Photo

I race my drop-bar Pugsley on gravel grinders, and I don't go above 15 psi (I was the second fastest fatbike of 30 registered for the 2018 Filthy 50):


Photo credit - https://markmanoutdoorphotography.com/

footnote/details: tires are Panaracer Fat-B-Nimble 26 x 4.0, rider is 170 lbs (likely 200+ lbs in this pic with all the water/ice/snow/limestone dust).
Hypno Toad is offline  
Reply With Quote
Old 10-31-18, 10:46 AM
  #12  
baj2
Junior Member
 
Join Date: Oct 2014
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Originally Posted by windhchaser View Post
i think it says 15 pounds or some low number that cant be correct
What size tire? I have two sets of 4.8" x 26", one is 15psi max, the other is 20 psi max. Either gets to be a rough mtb trail ride above 8-9psi. I've gone below 2psi for deep snow riding.
baj2 is offline  
Reply With Quote
Old 11-08-18, 06:18 AM
  #13  
Speedway2
Senior Member
 
Speedway2's Avatar
 
Join Date: Oct 2018
Location: Thornhill, Canada
Posts: 81

Bikes: Specialized Langster, Giant OCR, Marin Mtb, Felt Cruiser. VROD:)

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 29 Post(s)
I've mainly owned bikes with tires recommending 100-120psi.

When I (recently) bought my first fat tire bike (4"x26") the recommended max pressure on the tire was 20psi. I scratched my head and thought it must have been a mistake because at 20psi the tire felt "soft".

After searching the internet for answers (and reading this thread) I'm keeping my tires under 20.....
Speedway2 is offline  
Reply With Quote
Old 11-09-18, 12:39 AM
  #14  
MarcusT
Senior Member
 
MarcusT's Avatar
 
Join Date: Apr 2017
Location: NE Italy
Posts: 417
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 186 Post(s)
Originally Posted by windhchaser View Post
i think it says 15 pounds or some low number that cant be correct
My tires give 30 psi as the max, one day the trail I was riding had been washed out and I had to take a very long detour on paved road. Not sure if I put in 30 psi, but it was close, because it was the end of a long ride and I wanted to get home a fast as possible. No problems, no damage, it was a little bouncy though.
MarcusT is offline  
Reply With Quote
Old 11-09-18, 02:04 AM
  #15  
daoswald
Senior Member
 
Join Date: Apr 2008
Location: Salt Lake City, UT (Formerly Los Angeles, CA)
Posts: 712

Bikes: 2008 Cannondale Synapse (Aluminum) 105 Hardware and Fulcrum Racing Quattro wheels. Cannondale Quick CX 3

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 57 Post(s)
Originally Posted by windhchaser View Post
i think it says 15 pounds or some low number that cant be correct
You would need tires with a capacity of 371 liters to put 30 pounds worth of air in them.
daoswald is offline  
Reply With Quote
Old 11-10-18, 06:54 PM
  #16  
lmtada
Junior Member
 
Join Date: Apr 2007
Location: Edmonton, Alberta, Canada
Posts: 13

Bikes: Trek Fuel 100, GT Road Bike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
12 lbs in Mine.
lmtada is offline  
Reply With Quote
Old 11-11-18, 01:57 PM
  #17  
baj2
Junior Member
 
Join Date: Oct 2014
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Originally Posted by daoswald View Post
You would need tires with a capacity of 371 liters to put 30 pounds worth of air in them.
PSI is pounds/square inch = force density, not a weight. If it was a weight few would be able to lift their road bikes with two 100+lb tires.

The best way I've found to think about tire pressure is this. The air pressure in your tires is supporting the weight of you, your bike, and your gear. The tire will deform on the bottom based on the pressure in the tire and the weight it's supporting. If you are 180lbs, have a 35lb fat bike and 10 lbs of clothing and gear, that's 225lbs. Roughly speaking, if your tires have 10psi in them they will deform to create 22.5 inch^2 of ground contact to support that weight. If you run 5psi the tires will deform to create 45 inch^2 of ground contact.

If you are riding on loose or new snow, the lower the pressure you can run in your tires, likely the better your bike will perform. It varies with snow conditions of course. The pressure in your tires (PSI) roughly equates to how much force your tires are putting on the snow/inch^2. The example above is basically me when I ride in the winter, so at 2psi my 4.8" tires are getting flat enough on the bottom to create a total of ~112.5 inch^2. And yes, the tires look ridiculous and it is a heck of a lot of work to pedal, but it's pretty impressive when you are grinding your way through 10" of fresh snow.
baj2 is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service