potentially dumb air pressure question - BMW Luxury Touring Community
 
LinkBack Thread Tools Display Modes
post #1 of 12 Old Sep 23rd, 2006, 7:41 pm Thread Starter
Senior Member
 
petevandyke's Avatar
 
Join Date: Jun 2006
Location: Dallas, TX, USA
Posts: 1,741
potentially dumb air pressure question

OK, I invested in not one but two roadgear digital air pressure gauges based on advice in the threads.

One thing I discovered was the $50 gauge I had been using wasn't accurate--when it read 42 lbs on my front tire, both of the roadgears showed 38.

It did, however, raise a question.

There's been plenty of discussion on "how long should I let the bike sit before I can consider the tires to be at 'cold' to measure air pressure?" and even "if I have to ride five miles to the nearest gas station with an air pump, how much should I compensate...and if I check the tires in the morning when it's 73 degrees, how different will it be at noon when it's 92 degrees outside, and should I adjust tire pressure?"

So here's my potentially dumbass question of the evening...

If the ol' LT is on the center stand, and I am checking the front tire pressure, would it make a difference in the pressure reading if the front tire were DOWN vs. IN THE AIR?

Should tire pressure be checked with the tires under load, in other words? If so, does that mean we should be checking with the bikes on the side stand (and to take that even further into the ridiculous, should we find someone who weighs about what we do to sit on it as we do. or better yet, have someone else check air pressure when WE sit on the bike, balanced upright, with just enough toe pressure from both feet down to keep it upright?


For the sake of science, I tested the front tire air pressure on the center stand with the tire under load (tire down) and then with weight on the back, lifting the front wheel in the air, and the gauge which reads in .5 lb increments showed zero difference. And knowing who I am posting this to, I repeated it five times with the same result.

Reason I ask is this...I had metzeler me880's with about 1,000 miles on them, took a 500 mile trek to southern TX a week and a half ago, and was heavy on the throttle. When I got down there, I had worn down the rear tire horribly (thank you, shitty overpriced tire gauge!!!) and picked up a small cut. $220 lesson learned about underinflation, hot asphalt and long miles.

So, emperors of engineering, what's the scoop? (and yes, I anticipate a few "what's it matter, just check before you ride and keep it at 42 front, 48 rear" responses)

Pete the tire destroyer

========================================
When life throws you a curve, LEAN INTO IT!!!
2000 R1100RT-P...R.I.P. "Old motorcycle"
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

2004 K1200LT "Lick and Tickle"
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


FU*K Cancer. If I have one more MRI, I'll stick to the refrigerator door.
petevandyke is offline  
Sponsored Links
Advertisement
 
post #2 of 12 Old Sep 23rd, 2006, 8:14 pm
Senior Member
 
Join Date: Apr 2002
Posts: 14,434
Hey, Pete - not able to provide a definitive answer to your question(s), butt do have a suggestion. Get a SmarTire system installed and you can read what that unit does with temperature compensation.

Me? Even tho I have the system, I still check Toad's air pressures of a morning, using an Accuguage unit and without regard to whether on the centerstand or the sidestand. I think 'any' difference there, is gonna be minuscule and prolly not measurable by most tire pressure guages.

BTW - I haven't scientifically kept records, butt the SmarTire system usually shows anywhere from 3 to 5 psi differences from a cold tire standard basis setting to hot tires. More than that and it goes on alert. HTH a leetle.
Dick is offline  
post #3 of 12 Old Sep 23rd, 2006, 10:46 pm Thread Starter
Senior Member
 
petevandyke's Avatar
 
Join Date: Jun 2006
Location: Dallas, TX, USA
Posts: 1,741
Ya' know, Dick, there are so many things I'd like to invest in...

my initial reaction is "gee, that smart tire system is about $200, that's too much right now" but had I done that two weeks ago, I wouldn't have been stranded in sh**hole Corpus Christi with a bald rear tire, begging dealerships to "pretty please order me a metzeler and install it" (BTW, it was a custom chopper shop, Kingpin Choppers, that was the ONLY place in 40 miles that would do it, every Harley, honda, kawi, and suzuki dealership refused--so much for a "brotherhood....") and spending MORE than $200 for the tire and mounting and balancing...

if only I weren't on Santa's naughty list, I could submit my "want it" list of...

-smart tire system
-remus exhaust
-replacement chip and timing remapping
-intercom system
-Ohlins suspension
-retrofitted electro-hydraulic centerstand
-gore-tex raingear
-DVD-Audio and MP3 12-disk changer switch-out
-heated vest, pants, gloves for cold weather
-top case and saddlebag liners
-HID upgrade for headlight

oh...and

the reigning Miss Asia as a passenger (would settle for any Miss Texas contender from the last 15 years)


does anyone know of a Sugar Mama who is shopping?

lol

========================================
When life throws you a curve, LEAN INTO IT!!!
2000 R1100RT-P...R.I.P. "Old motorcycle"
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

2004 K1200LT "Lick and Tickle"
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


FU*K Cancer. If I have one more MRI, I'll stick to the refrigerator door.
petevandyke is offline  
 
post #4 of 12 Old Sep 23rd, 2006, 11:03 pm
Prodigal Son
 
early1's Avatar
 
Join Date: Aug 2004
Location: Dallas, TX, USA
Posts: 1,297
Cool Just Do It

[QUOTE=petevandyke]
-smart tire system -JUST DO IT--- My 2nd Farkle
-remus exhaust -My 5th Farkle--Have it--Do the SmartTire 1st
-replacement chip and timing remapping -_SOON, I think
-intercom system -IntaRide-RP-1--Cost Effective-Excellent per $ spent
-Ohlins suspension -MY NEXT Purchase er --Farkle
-retrofitted electro-hydraulic centerstand - ???Man that will Hurt--($$$$$)
-gore-tex raingear -Look at the FrogToggs Or the Frogg Togg Elite
-DVD-Audio and MP3 12-disk changer switch-out -? May buy the Dice- But the IPOD through the cassette ain't half bad
-heated vest, pants, gloves for cold weather -?? Yeah-but silk and polypropylene are CHEAP
-top case and saddlebag liners-Bought used on this site-cheap - keep your eyes open
-HID upgrade for headlight -My 1st Farkle and WORTH it

oh...and

the reigning Miss Asia --- WAY TOO HIGH a Maintenance Cost

ed early
Life is a Blind Curve , Just Ride It, Low and Inside
'00' Canyon Red

Last edited by early1; Sep 23rd, 2006 at 11:12 pm.
early1 is offline  
post #5 of 12 Old Sep 23rd, 2006, 11:56 pm Thread Starter
Senior Member
 
petevandyke's Avatar
 
Join Date: Jun 2006
Location: Dallas, TX, USA
Posts: 1,741
[QUOTE=early1]
Quote:
Originally Posted by petevandyke
-smart tire system -JUST DO IT--- My 2nd Farkle
-remus exhaust -My 5th Farkle--Have it--Do the SmartTire 1st
-replacement chip and timing remapping -_SOON, I think
-intercom system -IntaRide-RP-1--Cost Effective-Excellent per $ spent
-Ohlins suspension -MY NEXT Purchase er --Farkle
-retrofitted electro-hydraulic centerstand - ???Man that will Hurt--($$$$$)
-gore-tex raingear -Look at the FrogToggs Or the Frogg Togg Elite
-DVD-Audio and MP3 12-disk changer switch-out -? May buy the Dice- But the IPOD through the cassette ain't half bad
-heated vest, pants, gloves for cold weather -?? Yeah-but silk and polypropylene are CHEAP
-top case and saddlebag liners-Bought used on this site-cheap - keep your eyes open
-HID upgrade for headlight -My 1st Farkle and WORTH it

oh...and

the reigning Miss Asia --- WAY TOO HIGH a Maintenance Cost



I've re-thought it all...

Keeping my Miss Asia or Miss Texas contender...

she can check the tires
would rather hear her than the remus exhaust
won't have enough energy to worry about riding fast
Whispers in the ear are intercom enough
a suspension that bounces = holding me tighter
I can put the bike on the centerstand all by myself--show off the muscles for the chickie and all...
rain gear? Wet ain't all bad
She can play DJ with the ipod and fm transponder
heated clothing? I'd have something better to keep me warm
Don't need case liners for lingerie (for her, smartass)
would be doing something other than riding at night, so no longer a need for HID lighting...


ahh well, fun to dream


still looking for that sugar mama...

========================================
When life throws you a curve, LEAN INTO IT!!!
2000 R1100RT-P...R.I.P. "Old motorcycle"
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

2004 K1200LT "Lick and Tickle"
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


FU*K Cancer. If I have one more MRI, I'll stick to the refrigerator door.
petevandyke is offline  
post #6 of 12 Old Sep 24th, 2006, 7:37 am
Senior Member
 
hschisler's Avatar
 
Join Date: Sep 2005
Location: Rushville, OH, USA
Posts: 7,755
Quote:
Originally Posted by petevandyke
...if only I weren't on Santa's naughty list, I could submit my "want it" list of...

-smart tire system
-remus exhaust
-replacement chip and timing remapping
-intercom system
-Ohlins suspension
-retrofitted electro-hydraulic centerstand
-gore-tex raingear
-DVD-Audio and MP3 12-disk changer switch-out
-heated vest, pants, gloves for cold weather
-top case and saddlebag liners
-HID upgrade for headlight

oh...and

the reigning Miss Asia as a passenger (would settle for any Miss Texas contender from the last 15 years)


does anyone know of a Sugar Mama who is shopping?

lol
Pete, this is very funny. But (only somewhat) seriously, when I bought my LT last summer I started putting together a "wish list". The more info I gleaned from this site, the longer the list got.

I have found that -- over time -- items magically move from the list to the bike.

Howard Schisler
2015 BMW K1600GTL
2009 BMW K1200LT - 60k miles
2012 BMW F650GS (sold)
2005 BMW K1200LT - "Gray Ghost", traded at 120k miles
2005 Honda Shadow 650 (sold)
AMA, IBA, BMW MOA. CCRs: Braselton 2006, Osage Beach 2007, Duluth 2012


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
[/URL]
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
hschisler is offline  
post #7 of 12 Old Sep 24th, 2006, 8:36 am
Senior Member
 
Lynn_Keen's Avatar
 
Join Date: Jun 2002
Location: North East Florida, FL, USA
Posts: 2,234
Quote:
Originally Posted by petevandyke

So here's my potentially dumbass question of the evening...

If the ol' LT is on the center stand, and I am checking the front tire pressure, would it make a difference in the pressure reading if the front tire were DOWN vs. IN THE AIR?


Pete the tire destroyer
Just for the record, I believe you'll find that there should be no measurable difference in your tire pressure whether the tire is in the air or on the ground.

Lynn Keen
North East Florida
MSF #28271 Retired
'99 Canyon Red RETIRED AT 93,000 MI
'05 GRAPHITE METALLIC retired at 87,000 MI
'01 R1150 GS- totaled
'02 R1150 GS sold
'85 K100/EML sidecar sold
'11 R1200RT currently being enjoyed

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Lynn_Keen is offline  
post #8 of 12 Old Sep 24th, 2006, 4:27 pm
Senior Member
 
SilverBuffalo's Avatar
 
Join Date: May 2005
Location: St. Petersburg, FL, USA
Posts: 3,208
Quote:
Originally Posted by petevandyke
So, emperors of engineering, what's the scoop? (and yes, I anticipate a few "what's it matter, just check before you ride and keep it at 42 front, 48 rear" responses)

Pete the tire destroyer
Pete
The only variable you haven't taken into account is whether or not the air in your tires is fresh.
It's a proven fact that fresh air stays at the same pressure more consistently.
You do change the air in your tires at the same interval as your oil, right ?

Ok,ok so the previous statement is just sarcasm

This is the truth, of all of the things on your wish list the HID headlight conversion will give you the most bang for your buck, the CQ light ones are down to $110 now.


Hans
St. Petersburg FL

2002 K1200LTE
"Silver Buffalo" Totaled 5/06
2005 LT
"Esperanza"
BushtecGenesisTrailer
"Our preferred long distance carrier"



SilverBuffalo is offline  
post #9 of 12 Old Sep 24th, 2006, 4:56 pm
Miles of Smiles
 
Hilton's Avatar
 
Join Date: Oct 2002
Location: Touring Europe
Posts: 1,038
Garage
Smile No Cold Temperature Display

"OK, I invested in not one but two roadgear digital air pressure gauges based on advice in the threads."

I also use this gauge which I find to be great. Compact and accurate. Also fits over the valve stem easily with no loss of air (once you get the hang of using the deflator bump to centralize the seal) Usually leave my Thomas pump and gauge on board the bike but have noticed that after a cold night 5 C or so, when I check tires there is no digital display reading. If I keep the gauge in the sun or just hold it to warm it up a little, all is well. Any one else have this happen ?

Jenna: Ocean Blue '06
Hilton: Head of the Steering Committee.
Rena: The Committee.
ET4 Thing 1
ET4 Thing 2
Hilton is offline  
post #10 of 12 Old Sep 24th, 2006, 5:48 pm
Wrencher Extraordinaire
 
jzeiler's Avatar
 
Join Date: May 2004
Location: Hazel Green, AL, USA
Posts: 13,124
That is normal for LCD displays but usually they work down a bit colder. Should be good to -5C

John
2009 K1300GT Red Rocket
2009 R1200GS (Gone)
2005 K1200LT Ocean Blue Blue Wizard 110 K and counting...
2006 Bushtec Turbo+2 Spell
2004 330 Ci Convertable
K4AN

Have ridden a Motorcycle in all 48
But lack DE, MA, RI and CT with the 2005 LT

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
jzeiler is offline  
post #11 of 12 Old Sep 24th, 2006, 7:41 pm
Senior Member
 
Join Date: Dec 2002
Location: Shelton, CT, USA
Posts: 2,341
Well Pete, I have a Smartire and it is great for setting the bar first thing in the AM. I start off and within a few seconds I know what the air pressure is within one pound.. I already know from riding the day before that it will be time to adjust the tire pressure soon but the Smartire just gives me a visual acknowledgement that it is what I expect. My front drops about 1 lb pressure over a week to two weeks. Not sure why as I religiously clean the rim on every tire swap. My rear is usually fine. I just fire up my Black and Decker tire pump in the garage. For about $20 you can get yourself a great tool and you won't have to worry about how far you drove to the next station, if your quarter will run out or how dirty the ground is, and an assortment of other factors..

I would put the tire inflator on my wish list ahead of most of the stuff you have.. except maybe Miss Texas... In fact I would consider it in the same category as the HID.. safety.. Just like good tires.

My experience with the Smartire/Roadgear combo ... is the Roadgear is the bible and the Smartire is just a very convenient way to check tires EVERY startup. Worth the $200 and IMHO it is squarely in the safety wants lists. The Smartire should save you $200 over their life... If you don't have a Sirius Radio they might work well.. I have a Siruis radio and it interferes with the Smartire system. That is cause for another post. Bottom line is the Smartire is still worth $200..

My front tire air pressure will vary almost 20% from 65 degree tire temp to 125 degree tire temp and not always the same.. I can't place a reason but there must be a technical reason.. My rear doesn't see to vary quite 20% but the temps are higher. This summer I have seen up to 155 degrees. I have never seen the rear pressure above 58 lbs.

The more you are under inflated the quicker the pressure will rise. The more turns the tire takes the quicker the temps rise.. Net of this is unless you are going a straight 500 feet.. you need to have a way of putting air in in your garage or parking spot. Only thing you can do is say you need two lbs and check it when you start and when you arrive at the air station and put 2 lbs in.. just dont adjust to what you want.. i.e. 42..

BTW, The only time I lose a tire to cupping/feathering is with poor inflation and that usually is more than a thousand miles from home. Exactly what you don't want. I get great mileage out my stones.. probably better than most with Metzlers.. but it takes time. I am betting the Smartire will stop that.. Time will tell.. Still on my first set with the Smartire inserts.

Jack D. (Southern Connecticut)
2001 Black LTC
2015 Blue R1200GSA
jackd is offline  
post #12 of 12 Old Sep 24th, 2006, 7:44 pm
Member
 
torso's Avatar
 
Join Date: Feb 2004
Location: Everett, WA, USA
Posts: 51
air pressure and miss Texas

I always check the air pressure before I go and never saw a difference if the bike was on the centerstand or on the side stand. I would be happy with Miss any state for for the last 20 years - However, I don't think my wife would approve....
torso is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the BMW Luxury Touring Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
possible dumb question vman K1200LT 3 Apr 20th, 2007 7:02 am
New Owner... dumb question... Torpedo K1200LT 10 Jun 1st, 2006 6:30 am
Dumb Question I'm Sure Ekim Chit Chat 9 Apr 13th, 2006 5:40 am
Another dumb newbie question ... How to set the clock.. GSinNC K1200LT 8 Apr 2nd, 2006 3:04 pm
Another dumb question RE: KRS Mirrors GSinNC K1200LT 2 Mar 13th, 2006 8:55 pm

Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome