Tyre pressure?

[Maha]

Would tyre pressure of around 5-6 psi down on what you would normally run at, cause a notable difference on the bikes handling?

[Hitcher]

Would tyre pressure of around 5-6 psi down on what you would normally run at, cause a notable difference on how the bike handling?

Yes. Most certainly.

[SVboy]

Yes. Most certainly.

Too generic an answer. I think with all the variables the answer would be possibly. Think of tyre construction, bike type, road conditions and so on. Dropping 36 to 32f and 38 to 30r on a gsxr on sports tyres[s20 say]for the track would not change things too much on the road.

[Oscar]

Would tyre pressure of around 5-6 psi down on what you would normally run at, cause a notable difference on the bikes handling?

It would depend on the pressure you normally run at.
Tyres have a range of recommended pressures on any particular bike, depending on the load, speed, temp, road surface etc.

[Hitcher]

Tyres have a range of recommended pressures on any particular bike, depending on the load, speed, temp, road surface etc.

Yes. But riders generally seize on preferred settings that suit them best. Trial and error and all of that good stuff.

A 6 psi margin at a recommended tyre pressure of 36 psi is a 17% difference. For most riders that would be discernible. It may not be "dangerous" but it would be noticeable.

But I guess I made the mistake of responding to the first post in this thread.

[5ive]

I reckon it depends on the size of your tyre mostly.

After 10000kms my stock tyres were in need of replacement, so decided to get new ones the same day of heading off on my bike for a holiday. After the new tyres were fitted I noticed a massive difference in handling, cornering was a lot harder as the bike would not 'turn in' as easy on tighter corners. I was taking it easy to scrub the tyres in, and the roads were pretty smooth as well, so I thought maybe it was just the new (better quality) brand of tryes. It did not feel like they would have been safe at higher speeds or in sharper cornering.

So I decided to check the pressure when I got back and found that the person who had fitted them had inflated them more than what my stock ones were: 6psi over on the front, 8 psi over on the rear. Tyres were the exact same size as stock: 110/70 R17 front, 140/70 R17 rear.

I'm guessing they don't pay much attention to tyre pressures when fitting tyres, one psi for all

I deflated them to the stock pressures listed on the psi chart on my swingarm: 28 front, 32 rear, and handling was immediately improved again.

I don't know for sure what effect being under-inflated by 6psi would have on handling, but on my smaller tyres I'm guessing it would be soft and worse than over-inflation. Bigger bikes with larger tyres would probably be slightly softer, but still manageable.

[Maha]

Yes. But riders generally seize on preferred settings that suit them best. Trial and error and all of that good stuff.

A 6 psi margin at a recommended tyre pressure of 36 psi is a 17% difference. For most riders that would be discernible. It may not be "dangerous" but it would be noticeable.

But I guess I made the mistake of responding to the first post in this thread.

I have always run at 42 rear and 36 front. Checked the psi yesterday and the rear was around the 36 mark front at 32. First time I have checked the tyre pressure since owning the bike, a little remiss of me I know, should have done that the day I go it.

[Oscar]

Yes. But riders generally seize on preferred settings that suit them best. Trial and error and all of that good stuff.

A 6 psi margin at a recommended tyre pressure of 36 psi is a 17% difference. For most riders that would be discernible. It may not be "dangerous" but it would be noticeable.

But I guess I made the mistake of responding to the first post in this thread.

As an adventure/trail/enduro rider I'm used to a wide range of tyre pressures - my 950 runs 32 psi in the rear tyre on the road, but we may reduce that to 15 psi on the trail. Sometimes this means that it gets ridden on the road at the low pressure for a while, and it don't actually feel that much different (obviously it does have a great effect on tyre wear though).

It may be that the recommended tyre pressure has as much to do with tyre life as it does with performance, so maybe that 6psi is in that range...

[Gremlin]

It does depend on the tyre. I would expect most road riders to almost always answer yes. Something like the Pilot Road 3 / 4 is a soft carcass and yes, that kind of difference is going to make a difference in handling (both high and low).

Tyres with a stiff carcass will be less susceptible to adjustments in pressure. I've run a Heidenau K60 front (dual purpose and well known for being hard to fit) at 27-28 PSI and it still felt perfectly fine, which is closer to 10 PSI out.

That all said, I've also sworn that the tyre pressure was off, the bike felt weird, checked, and they were bang on. Suddenly the bike felt fine again. Your mind is a powerful thing.

[Oscar]

It does depend on the tyre. I would expect most road riders to almost always answer yes. Something like the Pilot Road 3 / 4 is a soft carcass and yes, that kind of difference is going to make a difference in handling (both high and low).

Tyres with a stiff carcass will be less susceptible to adjustments in pressure. I've run a Heidenau K60 front (dual purpose and well known for being hard to fit) at 27-28 PSI and it still felt perfectly fine, which is closer to 10 PSI out.

That all said, I've also sworn that the tyre pressure was off, the bike felt weird, checked, and they were bang on. Suddenly the bike felt fine again. Your mind is a powerful thing.

I shagged about with a new front tyre all day once, checking pressures several times and getting generally pissed off, swearing never to buy that brand again.
My steering head bearings were fucked...

[Ocean1]

It may be that the recommended tyre pressure has as much to do with tyre life as it does with performance, so maybe that 6psi is in that range...

Aye. 6psi down on full comp knobbs on the 525 is good for a quick lap of the neighbourhood and that's about it.
6pis down on my preferred Michelin PS3s on the Buell was certainly very noticeable.
So far the 1290 seems a little less fussy, but the Dunlop's a heavier carcase.

[Crasherfromwayback]

. First time I have checked the tyre pressure since owning the bike, a little remiss of me I know, should have done that the day I go it.

LOl. Lucky you haven't binned it so far then. If they were 46/52 you may well have.

[Big Dog]

I have to agreee with the depends statements.
On the DR I never notice until it is about 10 pound out unless I hit the motorway - then it feels like the icecapades. (I know because I let 10 pound out to try the difference on the gravel... made the deep gravel feel real steady)
On the CB I don't know in 35,000 I have never checked and found them to be more than 1/2 a pound out.
On the Hayabusa the front being out by 2 pound was really noticeable but 6-8 was neccessary to make the back feel weird.
On the GSX100f 4 pound either end was noticable... just.

[mossy1200]

I cant tell the diff between 42 and 36 rear other than loses traction easier at 42.

[Oliver12345]

Had my Rg rear tyre recently changed and they obviously don't do the tyre pressure properly, Noticed the rides were a bit odd and figured id go check the tyre pressure, The tyre had a pressure of 10PSI according the servo reader. QUite surprising how low it was really