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Dirk Diggler
25th May 2011, 19:31
Just wondering if sticking with the pressures specified in my manual are going to be best (36 rear, 30 front) or if more experienced XL owners have found that different pressures work better.

I'm open to all input.

Thanks all!

-DD

Bone
25th May 2011, 19:35
I assume you're still running the stock tires?

If so, those pressures are a great place to start.

You can try a little lower for a little more grip (but a little less mileage).

You can try a little higher for a little more mileage (but a little less grip).

You should probably run a little more for higher loads (be that if you're a particularly big guy or 2-up or you plus luggage etc).

Folkie
25th May 2011, 19:52
I always ran the recommended pressures with the stock tyres, and they were fine; never had a reason to vary them.

BKB
25th May 2011, 19:55
Old "rule of thumb" that I & some others use is 4lbs less than the max pressure stated on the side wall. Works well with every tire I've ever used, bike or car. Plus you don't have to remember anything but 4 less. Less to remember is always good for us old farts. 8-)

khaskins
25th May 2011, 20:06
It is a DOT requirement to print the tire pressure on the sidewall.

Bone
25th May 2011, 20:22
Old "rule of thumb" that I & some others use is 4lbs less than the max pressure stated on the side wall. Works well with every tire I've ever used, bike or car. Plus you don't have to remember anything but 4 less. Less to remember is always good for us old farts. 8-)

I don't mind rules of thumb, HOWEVER that one makes little sense to me.

If it were a percentage MAYBE MAYBE MAYBE, but considering tires on bikes, cars, trucks and trailers can vary in max pressure settings by nearly double the recommended spec, I don't like using a set figure below max.

Not to mention, I don't mind running my 4 wheel vehicles at higher pressures for better mileage and less grip because they won'd slide out from UNDER ME if I lose traction.

But MOTORCYCLES aren't as forgiving if you start to slide, so I prefer to run at the BIKE MANUFACTURER's recommendations or the tire manufacturer's model specific recommendations if available.


It is a DOT requirement to print the tire pressure on the sidewall.

It is only a DOT requirement to print the MAXIMUM ALLOWED PRESSURE - i.e. the pressure designed for carrying the MAXIMUM LOAD for which that tire is rated, and it is quite likely that same pressure WILL NOT yield the best traction for MOST applications.

The number one biggest DIYer mistake is airing their tires to the MAX sidewall pressure thinking that is "best" for all applications and that is simply incorrect.

BWP 5p
26th May 2011, 13:35
The number one biggest DIYer mistake is airing their tires to the MAX sidewall pressure thinking that is "best" for all applications and that is simply incorrect.

"Nothing but the best for my baby":laugh:laugh:laugh

Yeh.........I'm just stirring the pot! It's raining again!:shhhh:p:p

Hey....let's talk about using Nitrogen!;):D:D:D

gerblawman
26th May 2011, 14:03
while we're on the topic of tire pressures, I have a question.

The other day I went out to check my tire pressure, but I was having a hell of a time getting a reading from the valve stem. It's almost like the valve is bent and not opening properly for a reading. When I am able to get a reading, it is below recommended level. To the same effect, it doesn't seem to be taking in air when I put more into it... any ideas?

Also, nitrogen would be great for bike tires I think. Has anyone done this?

St_Anger
26th May 2011, 14:35
My 2010 owners manual says 30 front & 40 rear.
Anything less than 30 upfront and the bike feels quite sluggish.
Service rep at HD told me i ought to run it even higher in the rear tire but i'm comfortable with it at around 38.

On the topic of nitrogen, Ive heard that in the event of a puncture you'd have less of a 'blow out' effect. Also that the tire would maintain its pressure longer and be less susceptible to temp variations......

Bone
26th May 2011, 15:16
while we're on the topic of tire pressures, I have a question.

The other day I went out to check my tire pressure, but I was having a hell of a time getting a reading from the valve stem. It's almost like the valve is bent and not opening properly for a reading. When I am able to get a reading, it is below recommended level. To the same effect, it doesn't seem to be taking in air when I put more into it... any ideas?

Also, nitrogen would be great for bike tires I think. Has anyone done this?

Not sure about the why, but I think my first thought would be to get a valve stem core tool and pull the stem (that is if they are mounted like car tire valve stems) to inspect it.

Nitrogen - probably more effort than it is worth. It's really only become a benefit for over the road trucks.

On the topic of nitrogen, Ive heard that in the event of a puncture you'd have less of a 'blow out' effect. Also that the tire would maintain its pressure longer and be less susceptible to temp variations......

Yes, the tire may maintain pressure longer, and be less susceptible to changes from heating up (but that's not necessarily a good thing, since specs are for cold tire pressures and they take into consideration a certain amount of additional pressure from heating up). The blow out effect sounds like myth.

Here's an article which addresses it in passenger cars

http://www.popularmechanics.com/cars/how-to/repair-questions/4302788


So, to answer your specific questions: With nitrogen, your tire pressures will remain more constant, saving you a small amount in fuel and tire-maintenance costs. There will be less moisture inside your tires, meaning less corrosion on your wheels. You will not be able to feel any difference in the ride or handling or braking, unless your tire pressures were seriously out of spec and changing to nitrogen brought them back to the proper numbers.


Here's a business article saying it's not worth it

http://www.foxbusiness.com/personal-finance/2010/09/09/filling-cars-tires-nitrogen-worth-added-cost/


An NHSTA test of hundreds of tires found the same thing, that nitrogen filledtires lost approximately two-thirds as much pressure as air filled ones.

<snip>


What about the tire deterioration issue? NHTSA testedboth air and nitrogen filled tires for aging. They found the results were"inconclusive."

BWP 5p
26th May 2011, 15:23
We also beat the snot out of the nitrogen debate on here one time!

It's about like: Oil, Oil Filters, Fuel Grade, tire pressures, chrome, handlebars, fat girls, skinny girls, tire brands, etc.!:laugh:laugh

Bone
26th May 2011, 16:01
We also beat the snot out of the nitrogen debate on here one time!

It's about like: Oil, Oil Filters, Fuel Grade, tire pressures, chrome, handlebars, fat girls, skinny girls, tire brands, etc.!:laugh:laugh

True dat...

Sleeper
26th May 2011, 16:47
We also beat the snot out of the nitrogen debate on here one time!

It's about like: Oil, Oil Filters, Fuel Grade, tire pressures, chrome, handlebars, fat girls, skinny girls, tire brands, etc.!:laugh:laugh
Did someone say Fram oil filters? :smoke

04xl1200c
26th May 2011, 18:42
what about running C02??? those tire repair kits are nice on the side of the raod and you can get C02 at the local paint ball store... wouldnt that be better than nitrogen?

Dirk Diggler
27th May 2011, 02:08
Thanks for the replies.

I have Pirelli Night Dragon tires on my bike, and so far the OEM spec'd pressures from the manual have worked fine. Just wanted to make sure I was doing everything possible to make things work the best they can.

As for the nitrogen thing... I'll just stick to the 78% blend that I've been running for years. ;)

Durockrolly
27th May 2011, 02:20
What about ice cream? Can we talk ice cream???:laugh

DaytonaSportster
27th May 2011, 03:58
I got Metz ME880's front and read with 40 and 45 PSI per there website.

Bone
27th May 2011, 14:16
Thanks for the replies.

I have Pirelli Night Dragon tires on my bike, and so far the OEM spec'd pressures from the manual have worked fine. Just wanted to make sure I was doing everything possible to make things work the best they can.


Check the Pirelli website. Something makes me want to say that Pirelli bought Metzeler or vice versa and that some of their tires may share compounds or designs.

ANYWAY if that's the case Pirelli may have something on their website.

Metzeler for instance recommends HIGHER PRESSURES THAN HARLEY DOES FOR THE OEM DUNGFLOPS - so Pirelli might too and IF so you want to run them because if they are like Metzelers, they wear prematurely at lower pressures.

SpartanDen
27th May 2011, 14:28
I am with Daytona.... I too have Metzlers and run 40 front and 44 rear. Have had good results. What ever pressure you determine is "right" for you and your bike, check it regularily!! Like weekly or before any trip!
I carry a co2 cartridge kit with plugs on trips. I found that it takes a min of 4 cartridges to put enough air to get you someplace. Air is fine, nitrogen costs $$$ as does CO2. Why bother if you check and maintain?!

Bone
27th May 2011, 22:21
Download the Tire Fitment PDF from the Pirelli website - it has a fitment guide and recommended MIN/MAX pressures for their tires.

http://www.us.pirelli.com/web/motorcycle/tireguide/default.page

For the XL1200L/N - with Pirelli N Dragons it says

Front - Min 36 / Max 42
Rear - Min 44 / Max 50

So as I guessed, it sounds like the Pirellis are designed to run with more air than the stock DUNGflops.

Mindgame
29th May 2011, 03:20
The tire pressure on the sidewall is an average number, to get the actually tire pressure that should be run you would have to use weight calculations and compare that to how you ride the bike. I know for aviation they don't even print number on the side wall. We use the weight and balance calculations to determine the tire pressure. I'll dig through my book(s) and to see if I can find the the information on the why's and how's if you are all interested.
I know when I used to race Autocross thats we would vary our tires pressure a lot between runs and you can tell as little as 2 or 3 psi difference with your pushing your car to the max. That being said we weren't exactly worried about gas mileage.

MadMax25
29th May 2011, 03:48
I don't mind rules of thumb, HOWEVER that one makes little sense to me.

If it were a percentage MAYBE MAYBE MAYBE, but considering tires on bikes, cars, trucks and trailers can vary in max pressure settings by nearly double the recommended spec, I don't like using a set figure below max.

Not to mention, I don't mind running my 4 wheel vehicles at higher pressures for better mileage and less grip because they won'd slide out from UNDER ME if I lose traction.

But MOTORCYCLES aren't as forgiving if you start to slide, so I prefer to run at the BIKE MANUFACTURER's recommendations or the tire manufacturer's model specific recommendations if available.




It is only a DOT requirement to print the MAXIMUM ALLOWED PRESSURE - i.e. the pressure designed for carrying the MAXIMUM LOAD for which that tire is rated, and it is quite likely that same pressure WILL NOT yield the best traction for MOST applications.

The number one biggest DIYer mistake is airing their tires to the MAX sidewall pressure thinking that is "best" for all applications and that is simply incorrect.

Hey Kev,
Tire pressure should take into
account, total weight of bike and rider.
A female rider at 125 lbs, and a guy,
weighing in at perhaps 250, may present
varying issues for the tire in question.
I believe the factory spec is a
starting point for an average weight rider.

Dirk Diggler
29th May 2011, 17:03
Download the Tire Fitment PDF from the Pirelli website - it has a fitment guide and recommended MIN/MAX pressures for their tires.

http://www.us.pirelli.com/web/motorcycle/tireguide/default.page

For the XL1200L/N - with Pirelli N Dragons it says

Front - Min 36 / Max 42
Rear - Min 44 / Max 50

So as I guessed, it sounds like the Pirellis are designed to run with more air than the stock DUNGflops.

Thanks for posting this! I'm thinking somewhere in the "happy medium" of those specified pressures should work fine. Something like 40 front, and 47 rear. Maybe a little less in the rear since I'm always solo? I know H-D recommended 4 PSI more if a passenger was on the bike.
I'm going out to the garage right now to check and/or adjust the pressures.

O.R. John
29th May 2011, 17:20
I think the most important thing to take away from this thread is that you should actually check your tire pressure before each day of riding. Temperature fluctuations have a pretty big effect on tire pressure.

Dirk Diggler
29th May 2011, 20:25
I think the most important thing to take away from this thread is that you should actually check your tire pressure before each day of riding. Temperature fluctuations have a pretty big effect on tire pressure.

Guilty as charged. I hadn't checked mine in almost a month, and last night I noticed it started feeling a little "squirrely" leaning into a corner, so I checked the pressures, and had this eerie sinking feeling when I realized I had 30 PSI in the front tire, and 7.5 PSI in the rear! By far, the dumbest thing I've done in recent times. Any XLF member feel free to slap, kick in the nuts, punch in the face, or whatever you feel... I deserve it.

Edit: It drives a lot better now. /facepalm :rolleyes:

O.R. John
29th May 2011, 23:36
Guilty as charged. I hadn't checked mine in almost a month, and last night I noticed it started feeling a little "squirrely" leaning into a corner, so I checked the pressures, and had this eerie sinking feeling when I realized I had 30 PSI in the front tire, and 7.5 PSI in the rear! By far, the dumbest thing I've done in recent times. Any XLF member feel free to slap, kick in the nuts, punch in the face, or whatever you feel... I deserve it.

Edit: It drives a lot better now. /facepalm :rolleyes:

No need for a slap. Glad you felt the 7.5 before you got hurt!

Bone
31st May 2011, 15:22
The tire pressure on the sidewall is an average number,

again, no, it is not an average it is the MAXIMUM pressure for maximum capacity.

Hey Kev,
Tire pressure should take into
account, total weight of bike and rider.
A female rider at 125 lbs, and a guy,
weighing in at perhaps 250, may present
varying issues for the tire in question.
I believe the factory spec is a
starting point for an average weight rider.

SORTA - yes, the spec provided by the manufacturer (bike or tire) is an "average" sure - probably based on a 180 lbs rider (judging from Harley's other specs such as seat height)


1 Prices listed are the Manufacturer's Suggested Retail Prices. Options such as color are available at additional cost. Prices exclude dealer setup, taxes, title and licensing and are subject to change. Dealer prices may vary.
2 Measurement reflects 180 lb. (81.7 kg) operator weight.

Now taking that into consideration a 125 lbs woman is removing 55 lbs from the spec, and a 250 lbs guy is adding 70 lbs to the spec.

Of course rubbermount sportsters weigh something like 560-580 wet weight, plus the 180 lbs spec = 740-760 lbs - lets average that to 750 lbs

so a 125 lbs woman riding an average sporty is 7% under spec
and a 250 lbs dude riding an avearge sport is 9% under spec

You really think 7-9% makes that big a difference?

Most OEM tire pressure specs I've seen either have a range or they say one spec for solo rider and another spec for 2-up or solo plus luggage.

Then we can start to talk about accuracy of gauges...are they off by a few percent too?

Bottom line, I stand by my earlier position - START with the manufacturer's spec (bike if using OEM tires or tire manufacturer if different and a spec is available), then add a pound or two for better mileage or subtract a pound or two for more traction.

Bob99
31st May 2011, 16:56
no need for a slap. Glad you felt the 7.5 before you got hurt!

+1

xllent01
31st May 2011, 17:31
All of this is subjective and very dependent on a riders riding style...Keep in mind that hard cornering, passengers, heavy loads and sustained high speeds will require higher pressures (up to that indicated on the sidewall


if your bike slides out you've already exceeded the max traction limits of that particular tire anyways...:doh


Too little in the front can lead to cupping and front washout on corners, as well as sidewall pinching, or bent wheels on sudden sharp edged bumps..


Too much in the front can make the front feel harsh...

Too little air in the rear can make a Sportster feel "swishy" because you already have a rear swingarm mounted through the trans (not to the frame) on a rubber mounted engine/trans combo. Ride Safe!!

flameryder
2nd June 2011, 00:36
Stock Tires, recommended pressure. Works for me.

Dave1200s
2nd June 2011, 05:47
CO2 is a smaller molecule and will cause MUCH more rapid air loss.

Dave1200s
2nd June 2011, 06:13
Too high pressure in either tire can allow the tire to be more easily lifted clear off the road if you run over small rocks or gravel. The same is true with tread that's worn thin.

I've tested many tires by riding along inclined curbs, also to scuff in new tires or tires that have sat in storage. When the tire slips, I don't fall since it slips just a few inches before hitting level ground.
Higher pressures can lessen grip and make the breakaway point more abrupt.

bjc3113
4th June 2011, 22:38
I have Michelin Commanders on rear it says MAX pressure 41 psi.

Bike manual says 40 max for 2up or heavier riders. I am 220 and I lug the wifes big azz around alot and have it at 40 and its fine.