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Main Area => General GS500 Discussion => Topic started by: bmf on June 06, 2015, 04:21:36 PM

Title: Tyre pressures
Post by: bmf on June 06, 2015, 04:21:36 PM
Had a bizarre thing today. Went on an advanced riding course and the trainer quizzed us on tyre pressures. He asked where we find the right pressure to pump them. We said manual,   swing arm,  etc. And he said, on the tyre. He said manuals give a basic all purpose pressure that works with most tyres, but you should pump the tyres close  to the max pressure stated on the tyre. In my case about 42 psi.  I'm not convinced - anyone ever heard of this?

Also at the end we were doing an interesting exercise in a short course with sharp bends, they marked the tyre edges with chalk and we could see how far over we were leaning from where the chalk has worn off. The aim was to get to know our limits and end up dragging your pegs. With my conti 110/70 on the front I pretty much wore all the chalk off on the sidewall up to the edge of the tread , but I was still not dragging my pegs. The instructor said I was tyre limited not bike limited, and he said it was better to be the other way round,  drag your pegs before you  run out of tyre. The road riders on the rear were about the same. The other limit is driver limit ;-)

The Harley crowd hardly wore off anything;-)
Title: Re: Tyre pressures
Post by: fetor56 on June 06, 2015, 05:23:08 PM
Front 33psi/Rear 36psi....that suits me.
Lean to your own capabilities,if u extent them you'll know effing quick.  :icon_sad:
Title: Re: Tyre pressures
Post by: twocool on June 06, 2015, 06:06:47 PM
Over inflation is incorrect...potentially dangerous...

The number on the side of the tire is NOT the proper inflation...the proper inflation goes bike by bike...based on the design of the bike...not the tire..

The inflation LIMIT on the tire is the max allowable for that tire...never exceed...but seldom if ever recommended in the owners manual...

Use the manufacturer's spec.

Cookie




Quote from: bmf on June 06, 2015, 04:21:36 PM
Had a bizarre thing today. Went on an advanced riding course and the trainer quizzed us on tyre pressures. He asked where we find the right pressure to pump them. We said manual,   swing arm,  etc. And he said, on the tyre. He said manuals give a basic all purpose pressure that works with most tyres, but you should pump the tyres close  to the max pressure stated on the tyre. In my case about 42 psi.  I'm not convinced - anyone ever heard of this?

Also at the end we were doing an interesting exercise in a short course with sharp bends, they marked the tyre edges with chalk and we could see how far over we were leaning from where the chalk has worn off. The aim was to get to know our limits and end up dragging your pegs. With my conti 110/70 on the front I pretty much wore all the chalk off on the sidewall up to the edge of the tread , but I was still not dragging my pegs. The instructor said I was tyre limited not bike limited, and he said it was better to be the other way round,  drag your pegs before you  run out of tyre. The road riders on the rear were about the same. The other limit is driver limit ;-)

The Harley crowd hardly wore off anything;-)
Title: Re: Tyre pressures
Post by: Big Rich on June 06, 2015, 06:30:23 PM
+1 Cookie. That max PSI rating is for when the front and rear tires are mounted to a bike that is carrying the maximum weight capacity.

BMF, what tires are you running - Avon? If you are and run them at 42 PSI, you are in for a miserable ride. I have Avon Roadriders on my GS450 and run them at 32 front / 36 rear. Have you ever heard of the 10% / 20% tire pressure guide?
Title: Re: Tyre pressures
Post by: bmf on June 07, 2015, 08:05:53 AM
Yeah, was quite surprised, im probably going to be one of those stool pigeons  and Report him.........
Title: Re: Tyre pressures
Post by: Slack on June 07, 2015, 01:45:14 PM
Quote from: bmf on June 06, 2015, 04:21:36 PMThe instructor said I was tyre limited not bike limited, and he said it was better to be the other way round,  drag your pegs before you  run out of tyre.

Sounds like not only does your instructor know nothing about tire's, but he's never ridden a dual sport either.
Was this an MSF course?
Title: Re: Tyre pressures
Post by: MeeLee on June 07, 2015, 04:11:51 PM
The tire pressure on the sidewalls is rated for max psi under load.
That means, you still have leeway on it, when it's not under load.
You could pump up the tires to 41psi, but it'll feel rock hard. Also the tires are more prone to breaking and leaking that way.
Same goes for when you have it under 30PSI.
30PSI is round about the minimum you'd want to go on any vehicle.
The tires will feel soft, gas mileage will suffer a few MPGs.
under 27PSI on most bikes and cars, the tire will look visibly deflated, and could be a danger on the road,

Optimal values are between 30PSI and 35PSI for most situations.

Personally I pump them up to 38PSI, and check them bi-annually.
If they're low on air, (like have a leak) I'd feel it.
If I would only put 30PSI in them, I will have to check them more often, as a tire automatically deflates over time, even without a leak or spike through them.

Good tires keep their air for many miles. Often a year to 1.5 years, before they need more air.
Title: Re: Tyre pressures
Post by: bmf on June 07, 2015, 07:40:10 PM
Where could we possibly go from here!
Title: Re: Tyre pressures
Post by: Big Rich on June 07, 2015, 07:50:55 PM
I would definitely start with checking them more than twice a year....

Edit: here's the online article that explains the 10% / 20% pressure thing I explained earlier. Good reading, IMO.

http://www.mad-ducati.com/Articles/TirePressure.html
Title: Re: Tyre pressures
Post by: Atesz792 on June 08, 2015, 12:50:56 AM
Around here you're obligated by law to check your tire pressures weekly. Of course, nobody does that, but 2 years is just asking for problems...
Title: Re: Tyre pressures
Post by: twocool on June 08, 2015, 04:06:49 AM
The Internet can be a source of a lot a BAD ADVICE...beware! :icon_twisted:

Cookie






Quote from: Atesz792 on June 08, 2015, 12:50:56 AM
Around here you're obligated by law to check your tire pressures weekly. Of course, nobody does that, but 2 years is just asking for problems...
Title: Re: Tyre pressures
Post by: MeeLee on June 08, 2015, 07:23:41 PM
It's not advise.
I just check em annually, or longer.
We all can read the theory, but hardly ever keep them.
In fact, MSF course recommends you to check tires before every run, but I think hardly anyone does it.
I think most people check em when it's getting a bit deflated, or, like me, when a year or so has passed, and I'm left wondering if these suckers really have air in em, because I never notice them being empty....

And that is what a lot of people do in reality.
They don't check em before every ride, but whenever they seem to feel soft...
Not saying that's the way to do it, but that's the way it's mostly been done...
Just saying...
Title: Re: Tyre pressures
Post by: crackin on June 09, 2015, 12:21:33 AM
Quote from: twocool on June 08, 2015, 04:06:49 AM
The Internet can be a source of a lot a BAD ADVICE...beware! :icon_twisted:

I couldn't agree more, but im sure i read somewhere that the air inside the tyre goes stale after about a month so you should let them all the way down and put fresh air back in them.
Title: Re: Tyre pressures
Post by: Janx101 on June 09, 2015, 03:57:36 AM
Only in the countryside! Where fresh air lives.... city air is stale anyway so then it's fine!