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Author Topic: Higher Tyre Pressure Cause Less Vibrations !  (Read 1199 times)

singhg5

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Higher Tyre Pressure Cause Less Vibrations !
« on: August 18, 2010, 03:27:10 AM »
Today, my front tyre air pressure was at 17 psi and rear 27 psi.  I went to a gas station and pumped some air so that front tyre reached 22 psi and rear 32 psi.  Guess what ?  My bike rode better and had significantly LESS vibrations at the handle and overall in the bike.

This is the second time that I have noticed that my G5 runs smoother with a slightly higher tyre pressure than that recommended in the Owner's Manual (18 psi front and 28 psi rear for solo rider).

What is the explanation for this totally unexpected behavior of my G5 ?
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SSR

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Re: Higher Tyre Pressure Cause Less Vibrations !
« Reply #1 on: August 18, 2010, 06:45:29 AM »
No clue Singh Ji, in my case lower pressure helps but mostly more pressure in front tyre helps a lot rather then the rear.

shappers

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Re: Higher Tyre Pressure Cause Less Vibrations !
« Reply #2 on: August 18, 2010, 11:59:31 AM »
Hi Singh, I run my C5 at 26psi front and 28psi rear not sure about the affect on vibration but it does lessen the weaving at 70+ indicated mph.  Not gone, but less, along with leaning into the wind and lightly gripping the handlebar.

Cheers, Shappers.

Maturin

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Re: Higher Tyre Pressure Cause Less Vibrations !
« Reply #3 on: August 18, 2010, 01:28:56 PM »
I tried to find out what pressure suites best. Quickly I learned that the manual´s figures can´t be right, at least not for the road conditions in my country that are generally very good.
The best range lies between 1,8 and 2,1 bar (26-30 psi) for the front and 2,0 and 2,4 bar (29-35 psi) for the rear wheel. The pressure gauges are usually pretty inaccurate and the pressure varies with temperature so I find it difficult to name one fixed figure. Please remember that the correct tire pressure is also dependant on the tire´s brand and type. My experience is based on the original Avons. Their ability to stabilze the bike suffer under low pressure. Pumped up especially the steering precision in fast turns increases a lot.
But tire pressure killing vibes? That odd. Maybe a balancing issue? A hard spot of rubber on the tires surface whose influences are reduced by encreased pressure? Once I had this effect in a car that has been parked on a hot gully cover.
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ace.cafe

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Re: Higher Tyre Pressure Cause Less Vibrations !
« Reply #4 on: August 18, 2010, 01:40:57 PM »
Well, I don't know about the Avon Road Riders, but I will say that 18psi is way too low for Avon Speedmasters.
I had my front Speedmaster go down to 18psi one time after letting the bike sit a long time,and the damn thing was so squirrely I had to find an air pump at a gas station as fast as I could.

28psi in the front, with Speedmasters, is a good pressure.
I don't know who decided that 18psi was a good figure to put in the manual, but I suspect it's a typo, if it actually appears in the manual that way.
That's ludicrous!

I find it hard to swallow that ANY road tire would be specified to operate at 18psi.
If people are running that pressure, I would suggest much higher pressures be tried.
That might very well be the handling issue right there.
« Last Edit: August 18, 2010, 01:47:33 PM by ace.cafe »
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WillW

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Re: Higher Tyre Pressure Cause Less Vibrations !
« Reply #5 on: August 18, 2010, 03:12:00 PM »
The manual does indeed say 18 psi front and 28 psi rear (G5 with stock Avon Speedmasters). That's solo - it suggests a couple pounds more with pillion. I always felt 18 was too low, and put about 22, later increased to 26. Improved, but that front Speedmaster is squirrely by nature I think.
Running with 18psi at 60 mph and above could well explain poor handling!
I don't know what the C5 manual says, but Roadriders on a G5 are good at 27 front & 29 rear. I wonder why they used different tyres on these two bikes? Especially putting the cool modern tyres on the more retro looking bike  ???
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UncleErnie

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Re: Higher Tyre Pressure Cause Less Vibrations !
« Reply #6 on: August 18, 2010, 03:48:02 PM »
I would expect to wreck if I ran tires that low.  There's no sidewall at that low pressure.   For my lightest bikes, I run 30/32.  For bigger bikes I'll do a little higher. 
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Eamon

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Re: Higher Tyre Pressure Cause Less Vibrations !
« Reply #7 on: August 18, 2010, 10:44:22 PM »
The manual does indeed say 18 psi front and 28 psi rear (G5 with stock Avon Speedmasters). That's solo - it suggests a couple pounds more with pillion. I always felt 18 was too low, and put about 22, later increased to 26. Improved, but that front Speedmaster is squirrely by nature I think.
Running with 18psi at 60 mph and above could well explain poor handling!
I don't know what the C5 manual says, but Roadriders on a G5 are good at 27 front & 29 rear. I wonder why they used different tyres on these two bikes? Especially putting the cool modern tyres on the more retro looking bike  ???

I have Roadriders on my older iron barrel 500 and I find anything under 26 psi on the front to be squirrely.  I'd be afraid of crashing at 18 psi.  For both my Roadriders and the previous Speedmasters, I typically run 30 front and 32 rear.  I've even bumped it up to 32/34 and the bike's handling felt real crisp.

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