"correct" tyre pressure

[hwtan36]

finally after 2 years+ on the stock scorpion tyres

i replace it with PR4
manufacturer recommended 36F and 42R psi

i'm weight about 60kg, with a HB topbox, not much load in it.

should i go lower on the tyre pressure?
how should i test it?

hope i dont open a can of worm...

 

[tew47]

Whatever is says on the sidewall of the tire minus 10% is close enough. On cold tires.

 

[Beemerphile]

Some used to say that the pressure is right when it increases 10% from cold to hot. I think that is good race track guidance, but too low for best wear on the street. I shoot for 2 psi increase from cold to hot. Less than that and the tires are over-inflated and more than that, the tires are under-inflated.

After you do all the work, you will likely find that 36 front and 40 rear are about right.

 

[dduelin]

36/40 is good. I think 42 rear is better but I weigh a little more at 70 kg.

A rear Bridgestone T30 Evo at 38 psi cold will rise to 44 lbs hot when ridden fast and 42 cold to 46 lbs hot. 38 rises 16% and 42 only 9.5%. Until I installed tire pressure monitors I would routinely run somewhat lower tire pressures than I do now especially on rear tires.

The front tire on these bikes runs very cold unless you are pushing it hard with lots of braking for corners. 36 might rise to 39 or 40 under heavy use but just running down the road it barely gets to 38.

 

[mike5100]

Ambient temperature make a big difference. The recommendations assume you are setting them 'cold' ie you haven't been riding the bike, but in a workshop where the ambient temperature is 20 degrees. It follows that if you are setting them on a cold winters day at say about 3 degrees centigrade, you should underinflate by 10%. Vice versa if you are setting them on a scorching 35 degree summer day.
Mike

 

[hwtan36]

had a night ride just now

from 36F become 37psi

40R become 42psi

so far, the handling feels good.

will try on a hot afternoon tomorrow.

 

[mike5100]

had a night ride just now

from 36F become 37psi

40R become 42psi

so far, the handling feels good.

will try on a hot afternoon tomorrow.

From what little I have learnt about the subject it seems that you are underworking the tyre - probably because of your light weight. If the rubber was getting to the correct temperature the pressures should have gone up to about 40 front and 44 rear. As I understand it you should run the tyres softer so for instance try 33 front and it should get up to 36 when warmed up and 37 rear should get to 41 ...... but more informed riders may contradict this.
Mike

 

[Beemerphile]

but more informed riders may contradict this.

I wouldn't contradict it Mike, but it kind of depends on what you are trying to optimize. For instance, you will not get maximum traction and maximum tire life at the same setting. I think the 10% guidance (roughly 4 psi rise) gives optimum performance. However, 2 psi rise gives better tire life without sacrificing too much on grip. For me with PR4's that comes at 36/40. If I am just putting on road miles and not grinding the nubs off on the Dragon, I am likely to run 38/42 (especially if carrying a larger than normal load). Two to four psi rise is a good range to work within.

 

[hwtan36]

thanks guys, will try out different pressure.

 

[mike5100]

I wouldn't contradict it Mike, but it kind of depends on what you are trying to optimize. For instance, you will not get maximum traction and maximum tire life at the same setting. I think the 10% guidance (roughly 4 psi rise) gives optimum performance. However, 2 psi rise gives better tire life without sacrificing too much on grip. For me with PR4's that comes at 36/40. If I am just putting on road miles and not grinding the nubs off on the Dragon, I am likely to run 38/42 (especially if carrying a larger than normal load). Two to four psi rise is a good range to work within.

I reasoned that in the UK winter with crappy roads at close to zero deg C it's better to go for grip, and the 20 degree difference in ambient temperature compared to the reference pressure setting (36/42) combined with me always riding solo with no luggage suggested my cold settings should be 31/38. It's certainly improved the ride for me and when I have meaured the pressures after even a few miles they have increased by 10% so for me it's a safety thing.
Mike

 

[Batmite]

Tire manufacturers don't know what type of bike the tires are going to be put on. One thing for sure is under inflated tires are much worse for the tire than over inflated.
Under=possible cupping, uneven tread wear, sidewall deterioration. Over=harsher ride and that's about it. I've always used the bike manufacturer suggestions and adjusted
slightly from there.

 

[mike5100]

Tire manufacturers don't know what type of bike the tires are going to be put on. One thing for sure is under inflated tires are much worse for the tire than over inflated.
Under=possible cupping, uneven tread wear, sidewall deterioration. Over=harsher ride and that's about it.

.... errrrm, there could be more serious consequences. If an overinflated tyre doesn't get up to its working temperature (which it cant do because the walls can;t flex enough) then the rubber has less grip - quite apart from the contact patch being smaller
Mike

 

[Deleted member 1183]

.... errrrm, there could be more serious consequences. If an overinflated tyre doesn't get up to its working temperature (which it cant do because the walls can;t flex enough) then the rubber has less grip - quite apart from the contact patch being smaller
Mike

I tend to agree with this. Personally I am less concerned with tyre longevity than good leaned over grip from a tyre operating at a good temperature. I ran my PR4's at about 35/36 front and 36/38 rear on my NC with excellent grip evident wet or dry. My former KTM950SM which would have been similar in stature to the NC, ran 34/34 front and rear recommended by KTM. That also had good leaned over grip. Imho 42 psi is too much pressure on the rear of an NC riding solo.

 

[TN Thunder]

I may be wrong but I believe the tire pressure sticker indicates 36F/42R. That's what I run in my tires (that's cold pressure).

 

[GregC]

I Imho 42 psi is too much pressure on the rear of an NC riding solo.

Would weight of rider/gear impact optimal tire pressure, especially rear? It should reasonable that the rear might be better 2-4 psi under Honda's recommended 42, but it seems that would be affected by weight.


Sent from my iPhone using Tapatalk

 

[dduelin]

Would weight of rider/gear impact optimal tire pressure, especially rear? It should reasonable that the rear might be better 2-4 psi under Honda's recommended 42, but it seems that would be affected by weight.


Sent from my iPhone using Tapatalk

Until I installed tire pressure monitors on the MC I'd tend to agree that lighter riders could use 38-40 rear but read post #4 in this thread. 38-40 heats up far more than 10% indicating those pressures are a little low for me. There is no loss of grip at 42 for a 175 lb ATGATT rider - it heats up to 44 or so.

 

[Moto]

Fobo tpms

Until I installed tire pressure monitors on the MC I'd tend to agree that lighter riders could use 38-40 rear but read post #4 in this thread. 38-40 heats up far more than 10% indicating those pressures are a little low for me. There is no loss of grip at 42 for a 175 lb ATGATT rider - it heats up to 44 or so.

Installed the FOBO System.

 

[hwtan36]

i have come to a combo of 33 front and 40 rear

as i weight about 130lbs

and after the ride, the tyre warm up to 35 and 42 nicely.

if i had 36 psi infront, it wouldnt warm to to even 1 psi of increment.

and the grip is good even on a wet day.

 

[drdubb]

learned a lot from this thread.

 

[mike5100]

Until I installed tire pressure monitors on the MC I'd tend to agree that lighter riders could use 38-40 rear but read post #4 in this thread. 38-40 heats up far more than 10% indicating those pressures are a little low for me. There is no loss of grip at 42 for a 175 lb ATGATT rider - it heats up to 44 or so.

..... But shouldn't it be heating up to 46 ?
Mike