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Discussion Starter · #1 ·
Hello to everyone in 2022. I plugged a tyre just a week ago and a thought occurred to me. Years ago, when tyres on motorcycles were a lot narrower, I recall the recommended solo pressure for a 1973 Triumph Trident 750 I then owned as being 26 front and 28 rear. Bicycle tyres on an average, non mountain type of bike fitted with presta valves normally run about 70 psi, seemingly indicating that the narrower the tyre, the higher the pressure. I was wondering therefore, why we now are told to use 36 front, 42 rear for normal riding. My naked SV1000 handles perfectly well at these pressures but I would like it to be a little plusher riding. The suspension is set up for my weight of 9 stones when undressed, namely 130 lbs, so are the recommended pressures a cover all basis for people who may be a great deal heavier ? This isn't a problem as such, but I was just curious about it.

A Happy New Year to you all from me in Wales.
 

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First of all, you old narrow tyres were crossplys and modern tyres are radial with atotally different construction and sidewall stiffness

Then there's the informal agreement between tyre manufacturers to standardise on 36/42 to remove the need to keep consulting the tyre/bike manufacturer for the tyre pressure for that perticular model/tyre....they simplified it by all agreeing on 36/42.....nothing stopping you changing yours.

It could be agreed that you need different pressures im winter to that of summer. I prefer to aim for 36/36 hot which requires different pressures depending upon use and season
 

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Discussion Starter · #3 ·
First of all, you old narrow tyres were crossplys and modern tyres are radial with atotally different construction and sidewall stiffness

Then there's the informal agreement between tyre manufacturers to standardise on 36/42 to remove the need to keep consulting the tyre/bike manufacturer for the tyre pressure for that perticular model/tyre....they simplified it by all agreeing on 36/42.....nothing stopping you changing yours.

It could be agreed that you need different pressures im winter to that of summer. I prefer to aim for 36/36 hot which requires different pressures depending upon use and season
Thanks, I might well try lowering the pressures as you've suggested, when I put the bike back on the road in April. I guess it's a compromise for a degree of comfort vs tyre wear, particularly if wishing to avoid flatspotting the rear tyre in particular.
 

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The 36/42 is pretty much aimed t the fully loaded weight of the bike......and yeah, old bias belt cross ply's were like riding on wooden rims compared to radials, which need the air pressure
to keep their form.
I run 36/39 cold on hypersport tyres, and get briliant mileage and awesome grip levels.... I used to run lower pressures, but found, on the advice of the main tyre guy of thebrand i run to
bump them up......the thought scared me at first, but i tried it and love it.....and, yeah, i use the whole tyre on the road no chicken strips for this bloke....
 
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Discussion Starter · #5 ·
The 36/42 is pretty much aimed t the fully loaded weight of the bike......and yeah, old bias belt cross ply's were like riding on wooden rims compared to radials, which need the air pressure
to keep their form.
I run 36/39 cold on hypersport tyres, and get briliant mileage and awesome grip levels.... I used to run lower pressures, but found, on the advice of the main tyre guy of thebrand i run to
bump them up......the thought scared me at first, but i tried it and love it.....and, yeah, i use the whole tyre on the road no chicken strips for this bloke....
As it happens, I did try 35 front and 39 rear, last September, when I took the bike off the road due to having been suffering from a stomach ulcer. It did feel better than 36/42 for sure, especially as I'm so light a person. Almost unbelievably though, a couple of years prior, when then actually using 36/42 all the time, I ovaled a rear wheel on a very deep pothole and had to get an used rear wheel as a replacement, so I won't drop the pressures too drastically, bodily lightweight notwithstanding ! Many of the roads in my area of Wales are in a pretty awful state of repair.
Thanks very much for your comments and advice.
 

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I remember reading that if riding in the rain it's best to bump up the tire pressure. I've never tried this myself. Has anyone?
 

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I remember reading that if riding in the rain it's best to bump up the tire pressure. I've never tried this myself. Has anyone?
I prefer higher pressures in the rain, but, i already run 36/39 and i am 120kg plus gear (so about 260lb all up)..... lower pressures make the tyre flatten out and that decreases
the actual contact pressure per square inch and gives more opportunity for aquaplaning .......but there is a point where too much pressure doesnt allow the carcass of the tyre
to heat up and allow the tyre to deform properly over snotty stuff.

As it happens, I did try 35 front and 39 rear, last September, when I took the bike off the road due to having been suffering from a stomach ulcer. It did feel better than 36/42 for sure, especially as I'm so light a person. Almost unbelievably though, a couple of years prior, when then actually using 36/42 all the time, I ovaled a rear wheel on a very deep pothole and had to get an used rear wheel as a replacement, so I won't drop the pressures too drastically, bodily lightweight notwithstanding ! Many of the roads in my area of Wales are in a pretty awful state of repair.
Thanks very much for your comments and advice.
If the tyre is a very stiff construction type, and the pressure is too high, it is possible to transfer enough shock through the sidewall to deform a rim......seen it happen to a mates
bike.......
 
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Correct.....
 
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I get my tire pressures based on the heat and on the way the tread reacts. I’ve done a track day running 28 front / rear cold and after heating the tires I’m at 34-36 psi hot.
 
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hmm....interesting, i generally run 36 front + rear, next time im gonna have chance to go for a spin i bump up the rear to 39 and see how it is gonna feel on my pirelli angel GT's
so far weather sucky here in NE
 

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hmm....interesting, i generally run 36 front + rear, next time im gonna have chance to go for a spin i bump up the rear to 39 and see how it is gonna feel on my pirelli angel GT's
so far weather sucky here in NE
I am running Diablo Rosso 4 now, and previously Corsa 2 and 36/39 is excellent in both of them....
 
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Tyre pressures are a compromise
Suzuki and the tyre manufacturers have to spec a pressure that will work in cold weather and say city use, however in the height of summer on spirited ride in the country or even worse a track day, those cold winter city riding pressures are not ideal

This is why I use hot pressure of 36/36. The cold pressures required to achieve tjis are different for the time of year and the riding style, and need adjusting to suit.
36/42 is way too much in the summer on fast road riding or track use, but will be fine in the winter in the city.
 
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