Notices
Clydesdales/Athenas (200+ lb / 91+ kg) Looking to lose that spare tire? Ideal weight 200+? Frustrated being a large cyclist in a sport geared for the ultra-light? Learn about the bikes and parts that can take the abuse of a heavier cyclist, how to keep your body going while losing the weight, and get support from others who've been successful.

Tire pressures

Old 07-24-19, 09:46 AM
  #1  
pippin65
Senior Member
Thread Starter
 
pippin65's Avatar
 
Join Date: Jan 2007
Location: Sunny Florida
Posts: 66

Bikes: Trek fx 7.2, Giant Defy Advanced 3

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Tire pressures


hi all. I have a giant defy 3 and love it. However I never know what would be good tire pressures for me. I weigh 250 lbs. Iím running 28ís. Would love to hear some thoughts. My tires are contiís with max pressure of 115 psi.
Thanks

Last edited by pippin65; 08-16-19 at 08:45 PM.
pippin65 is offline  
Old 07-24-19, 10:19 AM
  #2  
pdlamb
Senior Member
 
Join Date: Dec 2010
Location: northern Deep South
Posts: 6,094

Bikes: Fuji Touring, Novara Randonee

Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1270 Post(s)
Liked 355 Times in 247 Posts
91.87 psi.

Seriously, you can either start with 115 psi, forget to air it up for a few days, and see if you notice higher rolling resistance or pinch flats, and pump it up if you do. Or start about 90 psi, ride it, next ride try 95 psi, and settle in on a good pressure.

A "good pressure" gives you speed (actual speed, not just you feel road buzz), you feel comfortable carving turns, and you don't pinch flat. It may change with road condition (pavement smoothness and potholes).
pdlamb is offline  
Old 07-24-19, 10:23 AM
  #3  
masi61
Senior Member
 
masi61's Avatar
 
Join Date: Oct 2005
Location: SW Ohio
Posts: 2,635

Bikes: Puch Marco Polo, Saint Tropez, Masi Gran Criterium

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 619 Post(s)
Liked 90 Times in 67 Posts
Originally Posted by pippin65 View Post
hi all. I have a giant defy 3 and love it. However I never know what would be good tire pressures for me. I weigh 250 lbs. I’m running 28’s. Would love to hear some thoughts. My tires are conti’s with max pressure of 115 psi.
Thanks
It depends on quite a few factors. Could you go into a bit more detail about some things? I’m just going to shoot off some questions to get the conversation started in no particular order, OK?

1) Does your Giant Defy 3 run harshly or are you happy with the ride as is?

2) Which specific rims are you running, how wide are they (internally and externally)?

3) Have you considered or are you running latex inner tubes or are you satisfied with butyl inner tubes?

4) Do you get a lot of flats?

5) Are you willing to monitor tire presssures before each ride?

6) What are the road surfaces that you typically ride on?

7) Are you hard or easy on your gear? For example do you plow over minor potholes or swerve a bit to find the smoothest line?

I’m running 25mm Challenge Criterium tires this year on my Velocity A23 wheels. I changed out the Velox cotton rim tape with thin 3M tubeless tape (2 layers) in order to get easier tire mounting. I think the thin tape also gives more interior volume which can allow lower tire pressures.

After riding a 2nd bike that is titanium as a backup for a year, I have now come to realize just how harsh my main aluminum bike is. This got me started on this ongoing experiment where I have been lowering tire pressures on the aluminum bike for increased grip and comfort. I weigh ~ #195 and have lowered the pressure in those 25mm Challenge tires with the Vittoria latex inner tubes to about 72psi front and 84psi rear. They are still plenty firm to where I don’t seem to have much sidewall deflection. The ride over broken pavement is much more tolerable. I highly recommend exploring a similar path for yourself. I would submit that running 115 psi in 28mm tires is WAY overkill. You could put some Vittoria latex tubes in there and even @ your body weight run them much lower in PSI than you are now. You will have to experiment to find the number that gives you the magical combination of low rolling resistance, flat protection and (wet/dry) cornering grip.

I was was going to look up the specs on a Giant Defy 3 just to see how compliant or stiff a bike it is.

But it if I were going to guess, I would think right off the top without seeing you ride or knowing what kind of roads you typically ride that 85 psi front and 92 psi rear would yield a marked improvement on your Continental 28mm tires (Grand Prix 4000’s perhaps?). If that combination was fine but the ride was still firm you could most definitely go even lower than that.

I don’t mean to be too preachy here, but personally I’m pretty stoked about this game changer for me of running slightly wider rims with more supple high thread count open tubulars with latex inner tubes and thinner tubeless rim tape at lower pressures for an amazing feel/ride - very noticeable!

Let me know about questions 1 through 7 above, good luck!

Last edited by masi61; 07-24-19 at 07:52 PM.
masi61 is offline  
Old 07-24-19, 11:24 AM
  #4  
rumrunn6
Senior Member
 
rumrunn6's Avatar
 
Join Date: Jul 2008
Location: 25 miles northwest of Boston
Posts: 24,863

Bikes: Bottecchia Sprint, GT Timberline 29r

Mentioned: 103 Post(s)
Tagged: 0 Thread(s)
Quoted: 3721 Post(s)
Liked 843 Times in 587 Posts
I would start with max in the rear & let the valve burp as you release the pump (I'm a Schrader guy). I figure I lose 5 lbs w/ a burp. bike tires have very little volume so be careful how much you burp but 5-10 lbs under max would be as low as I would go to start

the front, I've found, for me, can easily be 10-15 lbs lower than the rear
rumrunn6 is offline  
Old 07-25-19, 03:10 AM
  #5  
AmFaeEmbra
NewKidInTown
 
AmFaeEmbra's Avatar
 
Join Date: Dec 2011
Location: Edinburgh, Scotland
Posts: 115
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked 4 Times in 2 Posts
Here's an old post from way back on the very topic . . .
Psimet's tip of the Day
AmFaeEmbra is offline  
Old 07-26-19, 12:58 PM
  #6  
zowie
Senior Member
 
Join Date: Jul 2005
Location: US
Posts: 828
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 29 Post(s)
Liked 7 Times in 6 Posts
Nice bike.
People like to make things complicated.
At that weight, ballpark would be around the max for good pavement. Drop it a bit for rougher roads or hard dirt.
zowie is offline  
Old 07-27-19, 08:05 AM
  #7  
pippin65
Senior Member
Thread Starter
 
pippin65's Avatar
 
Join Date: Jan 2007
Location: Sunny Florida
Posts: 66

Bikes: Trek fx 7.2, Giant Defy Advanced 3

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by masi61 View Post
It depends on quite a few factors. Could you go into a bit more detail about some things? Iím just going to shoot off some questions to get the conversation started in no particular order, OK?

1) Does your Giant Defy 3 run harshly or are you happy with the ride as is? Nice

2) Which specific rims are you running, how wide are they (internally and externally)?
Stock Rims
3) Have you considered or are you running latex inner tubes or are you satisfied with butyl inner tubes? Iím good

4) Do you get a lot of flats? Never

5) Are you willing to monitor tire presssures before each ride? You bet

6) What are the road surfaces that you typically ride on? Asphalt in Florida

7) Are you hard or easy on your gear? For example do you plow over minor potholes or swerve a bit to find the smoothest line?
Smooth smoothie
Iím running 25mm Challenge Criterium tires this year on my Velocity A23 wheels. I changed out the Velox cotton rim tape with thin 3M tubeless tape (2 layers) in order to get easier tire mounting. I think the thin tape also gives more interior volume which can allow lower tire pressures.

After riding a 2nd bike that is titanium as a backup for a year, I have now come to realize just how harsh my main aluminum bike is. This got me started on this ongoing experiment where I have been lowering tire pressures on the aluminum bike for increased grip and comfort. I weigh ~ #195 and have lowered the pressure in those 25mm Challenge tires with the Vittoria latex inner tubes to about 72psi front and 84psi rear. They are still plenty firm to where I donít seem to have much sidewall deflection. The ride over broken pavement is much more tolerable. I highly recommend exploring a similar path for yourself. I would submit that running 115 psi in 28mm tires is WAY overkill. You could put some Vittoria latex tubes in there and even @ your body weight run them much lower in PSI than you are now. You will have to experiment to find the number that gives you the magical combination of low rolling resistance, flat protection and (wet/dry) cornering grip.

I was was going to look up the specs on a Giant Defy 3 just to see how compliant or stiff a bike it is.

But it if I were going to guess, I would think right off the top without seeing you ride or knowing what kind of roads you typically ride that 85 psi front and 92 psi rear would yield a marked improvement on your Continental 28mm tires (Grand Prix 4000ís perhaps?). If that combination was fine but the ride was still firm you could most definitely go even lower than that.

I donít mean to be too preachy here, but personally Iím pretty stoked about this game changer for me of running slightly wider rims with more supple high thread count open tubulars with latex inner tubes and thinner tubeless rim tape at lower pressures for an amazing feel/ride - very noticeable!

Let me know about questions 1 through 7 above, good luck!
Thanks for your nice response
pippin65 is offline  
Old 07-27-19, 08:09 AM
  #8  
pippin65
Senior Member
Thread Starter
 
pippin65's Avatar
 
Join Date: Jan 2007
Location: Sunny Florida
Posts: 66

Bikes: Trek fx 7.2, Giant Defy Advanced 3

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Likes: 0
Liked 1 Time in 1 Post
I just wanna go fast and not taco my rims. And they are so crazy expensive, rims in general.
For some reason I thought Iíd ride at mid-90ís and it works. Figured I didnít want my 250 bulk on maxed pressure tires.


Also on an unrelated front I was reading about oval chainrings and now I want one
pippin65 is offline  
Old 07-28-19, 08:59 AM
  #9  
bgdoyle
Member
 
Join Date: Jun 2018
Location: N Nevada
Posts: 44

Bikes: '18 Giant Defy,'18 Trek FX3, Early '90s Giant Iguana

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Likes: 0
Liked 1 Time in 1 Post
I have a Defy 2 with 28mm (act 30) Schwalbe pro one tubeless and run 75-80 psi in the back and 65-70 in the front. At this point in time I am at 240 lbs. Running the lower front pressure helps with cracks in the road and such and I don't feel I am beating up the front fork. The factory tubeless were 85 psi. Mine is a 2018, no sure when they changed to tubeless. Factory 25mm ran surprisingly smooth (@85) but I wanted a tire wider than the rim for rock protection.
I ride 3/4 mile on dirt (and rocks) before I hit pavement. I typically see a band of "clean" that is 5/8 inch wide on the front and 3/4 on the back when I get on the pavement. I feel that I am no where near too little tire pressure and the bike has a comfortable ride and no 'dragging' or sluggishness.

Last edited by bgdoyle; 07-28-19 at 09:07 AM.
bgdoyle is offline  
Old 07-28-19, 01:45 PM
  #10  
wsteve464
Senior Member
 
Join Date: Jul 2016
Posts: 553
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 155 Post(s)
Liked 68 Times in 59 Posts
Originally Posted by pippin65 View Post

Also on an unrelated front I was reading about oval chainrings and now I want one
You may not notice any difference with the oval ring. They were popular in the 80s and seem to be making a come back. I would spend my money on something else.

Here is one article on oval rings not from a manuf of them.

https://bikefitadviser.com/oval-chainrings/
wsteve464 is offline  
Old 07-29-19, 09:58 AM
  #11  
zowie
Senior Member
 
Join Date: Jul 2005
Location: US
Posts: 828
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 29 Post(s)
Liked 7 Times in 6 Posts
They were called Biopace. I still seem them sometimes on old bikes locked at the transit station.
I just assume because they were a thing for a little while and then totally disappeared until recently that they didn't perform as billed or had some other problem.
So I just wouldn't, especially if my existing rings aren't worn and don't need replacing.
zowie is offline  
Old 08-15-19, 09:14 PM
  #12  
tim24k
Senior Member
 
Join Date: Oct 2007
Location: NW
Posts: 737

Bikes: To many to list. I like them all!

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 55 Post(s)
Liked 35 Times in 28 Posts
Originally Posted by zowie View Post
Nice bike.
People like to make things complicated.
At that weight, ballpark would be around the max for good pavement. Drop it a bit for rougher roads or hard dirt.
+ one
I usually like run 5 to 7 lb less on the front tire. I feel it gives a little better road grip and more comfortable on the hands when riding chip seal roads.
tim24k is offline  
Old 08-16-19, 07:27 AM
  #13  
Milton Keynes
Senior Member
 
Milton Keynes's Avatar
 
Join Date: May 2016
Posts: 2,986

Bikes: Trek 1100 road bike, Roadmaster gravel/commuter/beater mountain bike

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1335 Post(s)
Liked 279 Times in 154 Posts
Can't say what works for you, but for me, keeping my 700x28's pumped up to about 90 PSI works better for me. Less rolling resistance and I can clock in a slightly faster time than I can if they're down to, say, 60 PSI. So, in short, for me it's closer to the max. PSI, the better.
Milton Keynes is offline  
Old 08-16-19, 08:41 AM
  #14  
frogbiscuit
Senior Member
 
Join Date: Aug 2008
Location: Spotsylvania, VA
Posts: 90

Bikes: Specialized Sirrus, Cannondale Catalyst, Diamond Back Extreme TG, Schwinn Mesa Runner with an 88cc 2 stroke engine

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 47 Post(s)
Liked 25 Times in 15 Posts
I am 240 and have 28's on my roadie at 100 psi.
My daily rider is a Specialized Sirrus (32's I think) and I run those about 90. I used to run them about 80 but performance seemd better at 90.
frogbiscuit is offline  
Old 09-12-19, 10:27 AM
  #15  
Oli_Aponte
Member
 
Oli_Aponte's Avatar
 
Join Date: Sep 2015
Location: Puerto Rico
Posts: 26

Bikes: Custom steel bicycles made by me and a Felt B12

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Liked 0 Times in 0 Posts
I'm 275 right now, I usually go for 105psi back, 95psi front (700x28c Gatorskins) Seems to be my sweet spot
Oli_Aponte is offline  
Old 09-12-19, 11:09 AM
  #16  
Daspydyr 
Pedals, Paddles and Poles
 
Daspydyr's Avatar
 
Join Date: Oct 2009
Location: Vegas Valley, NV
Posts: 5,492

Bikes: Santa Cruz Tallboy, Ridley Noah, Scott Spark 20

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 1160 Post(s)
Liked 59 Times in 49 Posts
I am @225 mostly. I run 110. I get flats when running lower pressures.
__________________
I think its disgusting and terrible how people treat Lance Armstrong, especially after winning 7 Tour de France Titles while on drugs!

I can't even find my bike when I'm on drugs. -Willie N.
Daspydyr is offline  
Old 09-12-19, 01:07 PM
  #17  
terrymorse 
climber has-been
 
terrymorse's Avatar
 
Join Date: Dec 2004
Location: Palo Alto, CA
Posts: 3,517

Bikes: Scott Addict R1

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 332 Post(s)
Liked 166 Times in 123 Posts
FYI, there is this online Road Bike Tyre Pressure Calculator.

For the OP's 250 lb weight and 28 mm tires, it recommends a pressure of 104 psi (7.0 bar).
__________________
Ride, Rest, Repeat
terrymorse is offline  
Old 09-12-19, 03:31 PM
  #18  
dagray 
Senior Member
 
dagray's Avatar
 
Join Date: Apr 2014
Location: Boardman, Oregon, USA
Posts: 1,719

Bikes: Orbea Orca,Raleigh Talus 29er, Centurion Le Mans 12 speed

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked 73 Times in 36 Posts
I am 365 pounds and run 25s at 105psi.
__________________
If you see an old fat guy levitating through town with his legs pumping furiously... well don't worry there is a bicycle underneath me.
dagray is offline  
Old 09-12-19, 09:43 PM
  #19  
scottmcd
Member
 
scottmcd's Avatar
 
Join Date: Feb 2017
Location: Kent Wa
Posts: 44

Bikes: Kona ESATTO DDL Cinelli Zydeco

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I am 260 28mm 100 rear 90 in the front
scottmcd is offline  
Old 09-13-19, 01:02 PM
  #20  
Podagrower
Senior Member
 
Podagrower's Avatar
 
Join Date: Nov 2012
Location: Central Florida
Posts: 660

Bikes: Giant Defy Composite, Spechialized Ruby (hers), Niner RLT9, Miyata 712, Condor ??

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 70 Post(s)
Liked 20 Times in 14 Posts
I'm a pretty firm believer in the Berto tire pressure method, but since that is also the max pressure for my rear tire, it works out kinda easy. If it's tubeless, you can get away with lower pressure. Tire with more volume = lower pressure, lower pressure = more compliant ride.

Originally Posted by pippin65 View Post
Also on an unrelated front I was reading about oval chainrings and now I want one
Originally Posted by wsteve464 View Post
You may not notice any difference with the oval ring. They were popular in the 80s and seem to be making a come back. I would spend my money on something else.
Here is one article on oval rings not from a manuf of them.
https://bikefitadviser.com/oval-chainrings/
Originally Posted by zowie View Post
They were called Biopace. I still seem them sometimes on old bikes locked at the transit station.
I just assume because they were a thing for a little while and then totally disappeared until recently that they didn't perform as billed or had some other problem.
So I just wouldn't, especially if my existing rings aren't worn and don't need replacing.
On that unrelated note, I kept the Biopace chainrings on my vintage Miyata just to piss off bike snobs. Shimano screwed up when they said Biopace was designed for cadence of under 90RPM and people decided they weren't meant for going fast and the idea died out (again, for a while). I'm not sure whether it's the chainrings, the trainer riding that I am doing, or what, but my cadence is way better than it used to be, 60RPM feels slow now and I am a reforming masher.
Podagrower is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
RoscoeP
Mountain Biking
8
06-07-18 07:51 PM
CNC2204
Clydesdales/Athenas (200+ lb / 91+ kg)
57
04-17-15 08:54 AM
spivey44
Road Cycling
33
01-11-13 04:33 PM
WHOOOSSHHH...
Road Cycling
52
02-23-11 04:54 PM
John E
Classic & Vintage
1
09-25-10 06:55 PM

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 - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.