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Main Area => General GS500 Discussion => Topic started by: peterscotts on March 11, 2013, 01:38:57 AM

Title: What Tyre Pressure
Post by: peterscotts on March 11, 2013, 01:38:57 AM
  :dunno_black: What Tyre pressure (psi) are you using in your GS :icon_question:
Title: Re: What Tyre Pressure
Post by: Twisted on March 11, 2013, 01:42:33 AM
33 front 36 rear. Never fails  :thumb:

Thing I noticed with the GS compared to my other bike is it is more sensitive to tyre pressures. Handles like poo when they are low. I put it down to the skinnier tyres.
Title: Re: What Tyre Pressure
Post by: codajastal on March 11, 2013, 01:46:58 AM
Quote from: Twisted on March 11, 2013, 01:42:33 AM
33 front 36 rear. Never fails  :thumb:

Thing I noticed with the GS compared to my other bike is it is more sensitive to tyre pressures. Handles like poo when they are low. I put it down to the skinnier tyres.
38 front and rear and I agree it handles like poo when low :icon_lol:
Title: Re: What Tyre Pressure
Post by: peterscotts on March 11, 2013, 02:04:42 AM
Thanks I'll try both, will let ya's know :dunno_black:
Title: Re: What Tyre Pressure
Post by: codajastal on March 11, 2013, 02:17:45 AM
Have to remember as well that Twisted's bike and my bike are totally different. Your bike is closer to his than mine I would think.
Title: Re: What Tyre Pressure
Post by: peterscotts on March 11, 2013, 02:43:38 AM
Sweet Cods.. I'll check em and whack in 33 front 36 rear and we'll see how she goes! :thumb:
Title: Re: What Tyre Pressure
Post by: CrazyDoc on March 11, 2013, 04:33:59 AM
Now is that for stock tires? Or is the psi change tire to tire?


Toole
Title: Re: What Tyre Pressure
Post by: codajastal on March 11, 2013, 05:51:37 AM
Shouldn't matter but each tyre has a psi rating if you're fussy
Title: Re: What Tyre Pressure
Post by: BockinBboy on March 11, 2013, 07:22:37 AM
Keep in mind if you are riding with a passenger, you should have slightly higher pressure in the rear tire than when riding alone.

- Bboy
Title: Re: What Tyre Pressure
Post by: Badot on March 11, 2013, 07:26:43 AM
+1 on handles like poo when low. I keep mine about 36/39
Title: Re: What Tyre Pressure
Post by: browncheetah on March 11, 2013, 09:15:45 AM
36/40.
Title: Re: What Tyre Pressure
Post by: twocool on March 11, 2013, 10:09:33 AM

why?

Cookie


Quote from: browncheetah on March 11, 2013, 09:15:45 AM
36/40.
Title: Re: What Tyre Pressure
Post by: IAmSpartacus on March 11, 2013, 01:39:59 PM
My tires are rated at 42psi.

As with all tires (or tyres), there are trade-offs in setups. More pressure typically translates into better fuel economy and handling. Less pressure can provide a "softer" ride and increase traction.

Remember though, that pressure increases with ambient temperature and heat buildup from the friction between pavement and rubber, so keep those factors in mind when reading a "cold" tire. For example, my tire could be filled to 42psi in my cool garage, but when I go out and carve canyons for a while in the 118* summer heat, that pressure could start pushing the tire's upper limits.
Title: Re: What Tyre Pressure
Post by: sledge on March 11, 2013, 02:12:22 PM
Quote from: peterscotts on March 11, 2013, 01:38:57 AM
  :dunno_black: What Tyre pressure (psi) are you using in your GS :icon_question:

I would experiment and find out what works for you.....not someone else  :thumb:

I wouldnt go much more than a couple of psi either side of manufacturers spec though.
Title: Re: What Tyre Pressure
Post by: twocool on March 11, 2013, 06:22:41 PM
A common misconception is that if a tire is rated to a certain max pressure, that you should use that pressure.  The proper pressure is determined by the bike, not the tire. (and is generally based on the weight, hence rear tire has more pressure than front, with rider extra pressure is used)

yes there are trade offs...but the bike manufacturer's specs are pretty much right in the middle giving a good combination of economy, handling, safety, etc.

Varying from that spec puts you in the category of "test pilot"

I will grant you, that under inflation is flat out dangerous, and bad in almost every respect.  But that being said, over inflation has its down sides as well.......you can argue that there may be a slight increase if fuel economy (I can find "myth-buster" type tests that show an advantage, and other tests that show none)...but overinflated tires will give poor ride...typically too much bounce in the tires, and lack of harmony with the design of the suspension.  Some say overinflated tire are more susceptible to road hazard damage.

As for heat..that is interesting....of course the recommended inflation is to be measured "cold" ... they don't really specify what that means, but generally standard temperature is considered to be 59 degrees Fahrenheit.  The rule of thumb is that for every ten degrees increase in tire temperature, you get one extra PSI.

Tires make their own heat as they "squish" as you ride......under inflated tires can get real hot.......
The spec for pressure takes into account that the tire will become hotter as you ride, and will have higher pressure as the tire heats......but in the extreme case of over 100 degrees.........your are adding at least 4psi or more over the cold pressure.........possible over inflation.........

To sum up...a slight over inflation is not going to hurt anything..and is most likely not perceptible......way over inflation is bad, as is under inflation........

BTW...tire pressure, oil, gas, and a couple other topics are argued endlessly on the internet...lots of bad information, and continuation of the typical myths

So....why not just use the factory spec??     33/36 solo.....33/41 dual.........

Cookie











Quote from: IAmSpartacus on March 11, 2013, 01:39:59 PM
My tires are rated at 42psi.

As with all tires (or tyres), there are trade-offs in setups. More pressure typically translates into better fuel economy and handling. Less pressure can provide a "softer" ride and increase traction.

Remember though, that pressure increases with ambient temperature and heat buildup from the friction between pavement and rubber, so keep those factors in mind when reading a "cold" tire. For example, my tire could be filled to 42psi in my cool garage, but when I go out and carve canyons for a while in the 118* summer heat, that pressure could start pushing the tire's upper limits.
Title: Re: What Tyre Pressure
Post by: IAmSpartacus on March 11, 2013, 08:44:05 PM
Sorry, I wasn't implying that I inflate my tires to 42psi- just that it is their maximum recommended pressure. I was neither supporting nor decrying the GS factory spec numbers, I was simply giving the logic behind why some people deviate from that number and that there are upper limits and variables to consider.

Of course as you pointed out, there are lower limits too- though I've never met someone who ever pushed that boundary on a bike. Low tire pressure is popular among 4x4 enthusiasts for off roading, but I've never heard of anyone claiming benefits (real or imagined) on a street machine.

I actually don't know what my tires are set at right now as I just has them changed at a shop. Now I'm curious, lol...
Title: Re: What Tyre Pressure
Post by: burning1 on March 12, 2013, 01:44:03 PM
Wow! I'm really surprised to see so many high tire pressures listed here, especially with radial tires.

GS500 is a relatively light bike, and shouldn't need quite so much pressure. I'd probably run 28-30PSI front and at most 32psi in the rear if I was on the street. My sport bikes usually end up being 30 front, 32 rear for street use, but the 620lb BMW gets 34 front, 36-38 rear.
Title: Re: What Tyre Pressure
Post by: burning1 on March 12, 2013, 01:47:03 PM
So, to elaborate a little... The purpose of tire pressure is to control the amount of deflection produced by the rubber under load. Tire pressure has a vital role in protecting the rim and rider from sudden shock when going over bumps, and has a major impact in controlling tire pressures.

If your pressure is too low, rolling resistance increases, and tire pressures increase dramatically. High temperatures can result in the tire working above it's operating temperature range. Too high and the tire won't deflect enough over bumps, resulting in a harsh ride. It also causes the tire to operate below it's temperature range, resulting in poor grip. It can also cause cold tearing if the tire is pushed too hard.
Title: Re: What Tyre Pressure
Post by: twocool on March 12, 2013, 04:12:58 PM




Right..........

So factory spec is 33/36.........

So far, nobody has shown any good reason to do otherwise!

Cookie




Quote from: burning1 on March 12, 2013, 01:47:03 PM
So, to elaborate a little... The purpose of tire pressure is to control the amount of deflection produced by the rubber under load. Tire pressure has a vital role in protecting the rim and rider from sudden shock when going over bumps, and has a major impact in controlling tire pressures.

If your pressure is too low, rolling resistance increases, and tire pressures increase dramatically. High temperatures can result in the tire working above it's operating temperature range. Too high and the tire won't deflect enough over bumps, resulting in a harsh ride. It also causes the tire to operate below it's temperature range, resulting in poor grip. It can also cause cold tearing if the tire is pushed too hard.