Tyre pressures - advice sought

[StoneY]

Ok, my turn to sound NEW ignorant and NOOBY
Ive owned a lot of bikes by my standards, very few by other peoples

Ive never seen a bike tire at over 40PSI till I checked my ST4- rear was 46 and front was 42!!!!!

I had been unhappy with the handling, felt like I was 'skating' and had no real grip yet I have supposedly awesome tires, Pilot Powers!

I reset the pressures to 35f/36r and wow shes gripping MUCH better and the ride feels a lot more....stickier, cushioned, smoother...... far more confident all round!

BUT the handbook also has the pressures up over 40 reccomended! Min 42 f and min 44 r!!!!!!!

ADVICE please,
Go with 'my feel' at mid 30's, or go with the books reccomended 40+ settings and look at the suspension setup to make the ride more as I enjoy?

I thought anything over 33 was 'sufficient' for the tire to work right?
Or do some flavours NEED that higher pressure despite rider feel?

[Elysium]

You could always try this Hydrogen or what ever that gas is racers like to put in their tyres. I think they do them to car tyres at Firestone now too.
On my bike I have shitty Shinko's on the front and they take ages to warm up and apparently if I use the recommended tyre pressure, I end up having too much pressure in the tyre as they warm up.

Oh and its "Tyres" not "Tires" :hitcher:

[st00ji]

nitrogen they use, much more stable (ie doesnt expand nearly as much with heat as plain air does)

costs a bit and you have to use it exclusively - moisture causes issues apparently, dont remember the details

[celticbhoy]

On mine I run 36F 38R (pilots also) but I have not played with suspension much yet. Other week on long run to Napier they were right down - as far as 28 I think for rear by the time I found a working air hose on the backroads. Was an awesome ride as seemed really sticky!!! Trouble was got to Napier and had scrubbed off the tread to almost slicks from being at least 50%!!! Was having bit of fun tho.....

[Lurch]

:lol: Nitrogen!


Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth's atmosphere.

78% !

[James Deuce]

If you're tired under pressure, have a sleep.

[avgas]

you ride to slow if you have to go below the recommended pressures.
May i suggest you swap bikes with me.

[_Shrek_]

it depends on what/where you ride don't forget running at 35/36psi cold they will heat up to 40/42 when hot, but if it feels right & you feel secure then these no prob
pm Larikin, Far-que, Mista, NighthawkNZ, McJim & see what they all :ride: those duc thingy's

[Morepower]

it depends on what/where you ride don't forget running at 35/36psi cold they will heat up to 40/42 when hot, but if it feels right & you feel secure then these no prob
pm Larikin, Far-que, Mista, NighthawkNZ, McJim & see what they all :ride: those duc thingy's

Agree , run what feels right for you. The TL is recommended 36 / 36 and thats where I tend to keep it .

[sinfull]

What temp you checking them at ?
What tyres ya checking ?
Ex race or road tyres ?
You happy with what ya found, coool !
Me i'm riding two up on race tyres (road ride) with 36/42 cold and it's working for me !
Same tyre i'd drop to 26/28 for the track !

[MSTRS]

You are checking those pressures cold? There should be a 10% increase in pressure once they reach optimum working temp.

[StoneY]

All good points gents

What I am looking for mostly, and can start to see a picture of what I need to know forming here, is what are the consequences of the different pressures and tyre (ty for that) vs lifespan/performance

I see obvious referral to soft= stickier but faster wear

Surely 46-42 is too high for a mere sport tourer thats not really being ridden as hard as it can (by a long measure indeed)

I have snuck it back up a touch to 38r and 36f, and have found what seems to be the perfect feel coming home over Mt Wainui

So, at the higher pressures I could not feel traction or road AT ALL, I imagine any lower than I went already would feel baggy....
Is it possible the 46-42 is for the concrete autobahns in europe?

[MSTRS]

What are the consequences?
It's a hard one to answer, cos all bikes are different. At a pinch, I'd have to say that too soft will lead to squirmy feel, overheating, odd wear patterns and reduced life. Too hard will lead to a harsh ride, lack of grip being under temp, increased wear in the centre.
I run the 750 at 33f and 37r - seems to be perfect (for me)

[sinfull]

All good points gents

What I am looking for mostly, and can start to see a picture of what I need to know forming here, is what are the consequences of the different pressures and tyre (ty for that) vs lifespan/performance

I see obvious referral to soft= stickier but faster wear

Surely 46-42 is too high for a mere sport tourer thats not really being ridden as hard as it can (by a long measure indeed)

I have snuck it back up a touch to 38r and 36f, and have found what seems to be the perfect feel coming home over Mt Wainui

So, at the higher pressures I could not feel traction or road AT ALL, I imagine any lower than I went already would feel baggy....
Is it possible the 46-42 is for the concrete autobahns in europe?Cold or hot ? 46 WTF ?

[Mom]

My bike handles like a piece of crap with the sort of pressures you would think "normal". Wobbles all over the show, wallows even :yes: Personally I would not have believed that a couple of psi in a tyre could make such a dynamic difference to my ride, but it does.

I dont have fancy pants tyres, but my bike is old and heavy and needs a bit more pressure in the tyres than you would normally think to use. If your handbook is saying run 42, then run 42. If she still handles like a dog then maybe you will have to review your suspension set up :yes:

[MSTRS]

My bike handles like a piece of crap with the sort of pressures you would think "normal". Wobbles all over the show, wallows even :yes: Personally I would not have believed that a couple of psi in a tyre could make such a dynamic difference to my ride, but it does.

I dont have fancy pants tyres, but my bike is old and heavy and needs a bit more pressure in the tyres than you would normally think to use. If your handbook is saying run 42, then run 42. If she still handles like a dog then maybe you will have to review your suspension set up :yes:

All true. But the Radian runs 90 profile tyres. That would mean that low pressures in yours would lead to huge sidewall flex...something that is less likely in a 55/70 profile.

[Mom]

All true. But doesn't the Radian run high/er profile tyres than a sprotbike? That would mean that low pressures in yours would lead to huge sidewall flex...something that is less likely in a 55/70 profile.

Well now, you are perhaps right, all I know is, run my tyres soft and I may as well pick the bike up and run around the corners, the bike will be as graceful as I am attempting to get round the corner :yes:

My point in case it was missed is tyre pressures make a huge difference in the handling of your bike, you can never assume what you always have used in the past will suit the tyres and bike you are riding now.

[MSTRS]

Well now, you are perhaps right, all I know is, run my tyres soft and I may as well pick the bike up and run around the corners, the bike will be as graceful as I am attempting to get round the corner :yes:

My point in case it was missed is tyre pressures make a huge difference in the handling of your bike, you can never assume what you always have used in the past will suit the tyres and bike you are riding now.

As usual, you speak with the voice of womanly wisdom.
I went and checked the Radian specs and changed my post, but you'd already quoted me. :bash:
Too soft is probably worse than too hard. Back when I had the 1100, I found a dodgy servo airpump gauge was delivering over 50psi when it was reading 40. The ride was harsh and a bit skittish.

[DMNTD]

IMO 36/38 is the magic set of numbers for most tyres for road riding.
In saying that when I've owned upright bikes I've run them within 1 PSI of each other and found them bang on.
IE: on both of my Superdukes plus also my Brutale I ran the tyres at 35/36 and got good stickablity© and at least 2000kms :yes:

[Mumbles]

89 ZXR 750 Running 36F 42R have always run this ...:woohoo:

[StoneY]

Great stuff everyone, and thanks MoM!
My old 1100 way back with higher profiles...memories, and answers
Sweet as everyone I now am happy to just tweak the tyre pressures, check em cold, and find MY zone

Awesome, question thoroughly answered, KB rox:rockon:

[ynot slow]

Bandit states 36/42 f/rsame two up.

[SPP]

IMO 36/38 is the magic set of numbers for most tyres for road riding.


Yep.

I changed to Pilot Power 2CT not too long ago (8000km on them now). I've played around a little with different pressures. 36/38 seems to be bang on for these (for me).

I tried lower 34/32-34 but the rear squirmed around a little too much for me and higher pressure didn't seem to be any less grip.

I commute a lot so raise to 36/42 weekdays to preserve them. The feel fine and are wearing quite well.

42/46 seems pretty high.

[p.dath]

Found this interesting article on the Continental Tyres (http://www.conti-online.com/generator/www/de/en/continental/motorcycle/themes/faq/hidden/airpressure_en.html) web site.

Basically they recommend running at the highest pressure level recommend by the motorbike manufacturer - even though some comfort will be lost doing this. They say to do this because the tyre pressures are chosen based on safety, not comfort.

They also talk about under-inflated tyres heating much more, and if you've read all the threads about racers, you'll know tyres have a limited number of heat cycles.

So my impression is that running the tyres below the manufacturers recommendations, while more potentially more comfortable, is likely to reduce the life of the tyres, potentially reduce safety, and reduce fuel economy.

[Ocean1]

on both of my Superdukes plus also my Brutale I ran the tyres at 35/36 and got good stickablity© and at least 2000kms :yes:


I changed to Pilot Power 2CT not too long ago (8000km on them now). I've played around a little with different pressures. 36/38 seems to be bang on for these (for me).

Yes, on the Buell it got pretty obvious when the PP's were out by more than a psi or so, the front in particular. I ran them at 36, front and rear, less than that and it felty like the front was folding, much more and it'd feel washy. The rear was less critical.

[crash harry]

Have a look here (http://two-wheels.michelin.com/2w/front/TyreSelector?lang=EN&cd_pays=3a2e&cd_marque=48434942&cd_modele=4a4b4d4d4a4e&cd_cylindree=4a4b434f4b4d&cd_annee=4a4a4e4a434f) at teh michelin reccomendations for an ST4s (I assume from your profile that's what we're talking about here?)

Seems they recommend Pilot Road with 2.2 bar front and 2.4 bar rear (that's 32 psi front and 35 psi rear in old money...). From my experience, pressures for powers and roads are similar for best handling, they're a similar carcass as far as I know.

I suspect that the pressures recommended in your manual are for tyres with soft-as-all-hell sidewalls or they're trying to get a million miles out of them or something... I've had a set of Dunlops on the R1 that performed best at 36/42 psi (front/rear) - the Michelins it's got on now run 37psi front and rear and feel brilliant at that.

[crash harry]

Found this interesting article on the Continental Tyres (http://www.conti-online.com/generator/www/de/en/continental/motorcycle/themes/faq/hidden/airpressure_en.html) web site.

Basically they recommend running at the highest pressure level recommend by the motorbike manufacturer - even though some comfort will be lost doing this. They say to do this because the tyre pressures are chosen based on safety, not comfort.

They also talk about under-inflated tyres heating much more, and if you've read all the threads about racers, you'll know tyres have a limited number of heat cycles.

So my impression is that running the tyres below the manufacturers recommendations, while more potentially more comfortable, is likely to reduce the life of the tyres, potentially reduce safety, and reduce fuel economy.

Basically true, though I would go with the recommended pressures from the Tyre manufacturer, not the Bike manufacturer. Too many variables in different tyre constructions. Interesting also that after stating that, Continental list tyre recommendations for different models, complete with inflation pressures. For the ST4s in question they recommend all sorts of tyres, all with 2.2bar front and 2.5bar rear (32psi / 36psi). They do make you accept an agreement that they take no responsibility for the recommendations and you're on your own if you follow them though..

[p.dath]

I wonder how much the "weight" of the rider has an impact on the recommend tyre pressure.

I assume when a motorbike manufacturer recommends a tyre pressue it must in part be in part based on the weight of the bike.

[Hiflyer]

I really dont know what difference the pressure makes to my bike, Ive only ridden my bike for long periods of time, (I rode my flatmate's bike for a wee bit but was too worried about adjusting to the riding position) Maybe I'll let it run down to below thirty then pump it up and c what hapens hahahaha

[MSTRS]

So my impression is that running the tyres below the manufacturers recommendations, while more potentially more comfortable, is likely to reduce the life of the tyres, potentially reduce safety, and reduce fuel economy.

Not necessarily. There are so many factors at work. It is finding the ideal combination for you that is most important.
For interest's sake - I have seen 'official' recommendations for my 750 at anywhere from 36/36 to 38/38 to 36/42. They can't all be right! I run mine at 33/37, and the last set of PR2s gripped and lasted pretty well. 18,000kms.

[Pixie]

They also talk about under-inflated tyres heating much more, and if you've read all the threads about racers, you'll know tyres have a limited number of heat cycles.

The limited heat cycle thing mainly applies to race compounds.No manufacturer would market a general road use tyre that deteriorated like this.It's begging for a court action.

The correct pressure for a given rider's style of road riding,is one that achieves a temperature increase of around 3 to 5 degrees from cold.

[MSTRS]

The correct pressure for a given rider's style of road riding,is one that achieves a temperature increase of around 3 to 5 degrees from cold.

No way. Be much more than that. At least on the surface of the tyre.

[vifferman]

The correct pressure for a given rider's style of road riding,is one that achieves a temperature increase of around 3 to 5 degrees from cold.
Isn't that supposed to be "a pressure increase of around 3 to 5 % from cold"?

[MSTRS]

Isn't that supposed to be "a pressure increase of around 3 to 5 % from cold"?

Still not right. If he means %, it should be around 10%. Anymore, and you are probably running too soft from cold. And vice versa.

[vifferman]

Still not right. If he means %, it should be around 10%. Anymore, and you are probably running too soft from cold. And vice versa.
Yeah, that's what I said - around 10%. :o

[grusomhat]

So if I run my tires at 41R/36F, what would be an acceptable pressure hot?

[MSTRS]

+4psi and +3.6psi
Personally, on your bike I'd start at 35f 38r

[grusomhat]

+4psi and +3.6psi
Personally, on your bike I'd start at 35f 38r

Sweet, that seems about how much they were up the other day. I need to find a guage though that I can trust. Might just buy a new pencil gauge. I'll give those pressures a run next time.

[v8s&2wheels]

Sweet, that seems about how much they were up the other day. I need to find a guage though that I can trust. Might just buy a new pencil gauge. I'll give those pressures a run next time.

Ha snap. Both still trying to get our pressures right ae. If you want you can borrow my gauge for a week or 2 until you get one. Im going to use it 2mrw and that should be me for a couple of weeks. let me know if you want it

[Pixie]

No way. Be much more than that. At least on the surface of the tyre.

Sorry,I must have suffered brain fade.
I meant to write: a pressure increase of 3 to 5 psi.

[MSTRS]

You're forgiven. But don't do it again, you hear?
Actually, +5psi is a bit much. Might be acceptable on the track, when that extra heat = extra stick, but un-necessary on the road and will seriously shorten tyre life.

[vifferman]

Sorry,I must have suffered brain fade.
I meant to write: a pressure increase of 3 to 5 psi.
That's what I said.
3 to 5 pissies.
Innit.

[KEN]

Check ya tyres B4 each big ride to what the manufactors specs on the frame,end of story....

[StoneY]

Got me a Tyre Gauge at a mates advice

Test them cold

Got em on 38r and 36f and man that bike is sweeeeeet

Oh man Tyre pressure is so fuckin important wow has this been an eye opener

I used to just leave it to the guys in teh shop....and they had me 46-42


Never again

[grusomhat]

Got me a Tyre Gauge at a mates advice

Test them cold

Got em on 38r and 36f and man that bike is sweeeeeet

Oh man Tyre pressure is so fuckin important wow has this been an eye opener

I used to just leave it to the guys in teh shop....and they had me 46-42


Never again

Wow that is high! you would be looking at almost 50 in the rear when hot!

[bigears]

Getting back to the Nitrogen thing it's a bigger molecule so you don't get the same leakage or expansion so more constant wear, we use it in our fire trucks so some of us boys have put it in our bikes $5 tyre and topped up for free and only have to pay when a new tyre is put on. Worth a Go?

[howdamnhard]

[QUOTE=Elysium;1129452262]You could always try this Hydrogen or what ever that gas is racers like to put in their tyres. I think they do them to car tyres at Firestone now too.
ERR don't use Hydrogen, that could be fatal (as in explosive). Nitrogen is the gas you are thinking of. It is an inert gas thus no fire or corrosion risk. It does not imbue tyres with magical properties though contary to popular belief.

[howdamnhard]

Getting back to the Nitrogen thing it's a bigger molecule so you don't get the same leakage or expansion so more constant wear, we use it in our fire trucks so some of us boys have put it in our bikes $5 tyre and topped up for free and only have to pay when a new tyre is put on. Worth a Go?

Take a look at the chemical periodic table. Oxygen is actually a bigger molecule than nitrogen. Air is made up about 78% N , 21% O and then various other gases. Nitrogen is an inert gas like Argon , it is relatively cheap and thus is has been used for many years in aviation for tyres to reduce the risk of fire and also corrosion.
You being a fireman will understand the less oxygen the better regarding fires.

[howdamnhard]

Got me a Tyre Gauge at a mates advice

Test them cold

Got em on 38r and 36f and man that bike is sweeeeeet

Oh man Tyre pressure is so fuckin important wow has this been an eye opener

I used to just leave it to the guys in teh shop....and they had me 46-42


Never again

Yeh tyre pressures are a lot more critical on bikes, check them often.