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Discussion Starter #1
Does anyone intentionally run their bikes at a different tyre pressure to that of the BMW specification?
My rear Metzeler Z8 was spent at 4500 miles running at 2.7 bar, it was mostly worn in the centre, which is indicative of over inflation, but i have two different tyre pressure gauges that read the same. So the tyre is replaced with a Metzeler roadtec 01.
Looking on Metzelers Data sheet i see there are some heavier bikes running the same size tyre at 2.4 bar, this made me think it would be safe to have a play with pressures.
I'm currently running 2.2 bar up front & 2.4 bar out back and my bike feels tonnes better. The front is more secure on cornering on both rough and smooth tarmac and has somewhat fewer road vibes coming through. I'm not really cornering any harder, yet my chicken strips have shrunk a few mm. Wet grip is now nothing short of spectacular.
I know i'm on a new rear tyre, but i have switched between BMW spec pressures and my own lower pressures a few times on this new rear tyre (the front tyre is still original) and i can definitely say the lower pressure is way better.

So, does anyone have experience or opinions on this?
 

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I run my Michelin Road 5 tyres, 34PSI front and 32PSI rear as opposed to BMW recommended 36PSI front/rear, Makes a remarkable difference the bike leans very smoothly into corners and is very stable. Just adding a couple of PSI and the bike is more unstable and falls into low speed corners. The pressure change was performed as part of a suspension setup, before then I'd always ran factory settings (as I didn't know any better to be honest) because that's what the factory said. When you think about it we are all different weights and the factory will assume the pressure settings for what they consider an average rider (in their view).

All I know is my bike is tons more confidence inspiring now with the new suspension and revised tyre pressures. That'll do for me! :)
 
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Discussion Starter #3
I run my Michelin Road 5 tyres, 34PSI front and 32PSI rear as opposed to BMW recommended 36PSI front/rear, Makes a remarkable difference the bike leans very smoothly into corners and is very stable. Just adding a couple of PSI and the bike is more unstable and falls into low speed corners. The pressure change was performed as part of a suspension setup, before then I'd always ran factory settings (as I didn't know any better to be honest) because that's what the factory said. When you think about it we are all different weights and the factory will assume the pressure settings for what they consider an average rider (in their view).

All I know is my bike is tons more confidence inspiring now with the new suspension and revised tyre pressures. That'll do for me! :)
I'm pleased to hear i'm not the only one who's found this. It is interesting that you have a lower pressure in the rear though, i think i'll continue to fettle the pressures.

Have you found that it affects your tyre mileage at all. Some sources suggest reduced mileage, and others suggest extended mileage...... the internet seems to only have opinions rather than actual facts on the subject.
 

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Can't say I've noticed any adverse wear, but even if they wore out faster I'd rather have the new confidence they give me as opposed to longer life.
 
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I have also started playing with my tyre pressures.
For my Turban, the suggested tyre pressure is 2.5 (36 psi) front and 2.9 (42 psi) rear.
Pressure all the same for 1 up, 1 up with luggage and 2 up.
Speaking to the super bike guys at work, they suggested I lower the pressure.
I am now running 2.2 (32 psi) front and 2.6 (38 psi) rear.
Way more comfortable, and like BD says, you don't have that feeling of falling into low speed corners.

I usually check the tyre temperature (by hand) after a ride, and they are warm.
I'm guessing I could drop the pressure a little more.
My weight is 125 kg with clothing, tool kit and back pack (about 275 pounds)

Anyone else have suggestions for tyre pressures?
 

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Discussion Starter #6
I have also started playing with my tyre pressures.
For my Turban, the suggested tyre pressure is 2.5 (36 psi) front and 2.9 (42 psi) rear.
Pressure all the same for 1 up, 1 up with luggage and 2 up.
Speaking to the super bike guys at work, they suggested I lower the pressure.
I am now running 2.2 (32 psi) front and 2.6 (38 psi) rear.
Way more comfortable, and like BD says, you don't have that feeling of falling into low speed corners.

I usually check the tyre temperature (by hand) after a ride, and they are warm.
I'm guessing I could drop the pressure a little more.
My weight is 125 kg with clothing, tool kit and back pack (about 275 pounds)

Anyone else have suggestions for tyre pressures?
One thing to consider is the most manufacturers suggest you check temperature on cold tyres as the pressure will naturally rise with temperature when riding. So a 36 PSI cold tyre and a 32 PSI warm tyre will have somewhat more than 4 PSI difference between them when they are both at the same temperature.
 

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Thanks Jellyhead
After a ride, I just feel with my hand.
If the tyre is too hot, then I pump it up a bit when it is cold.

After the ride home today, the rear was much warmer.
I played with the dampening before I left, so it is that or just that it was warmer in the afternoon.

Either way, I just like fiddling with the crappy suspension and tyre pressures.
Just when I think I have it, I don't, so I am actually quite clueless ?

Hopefully someone at work sees me fiddling with the suspension and tyres and thinks I know what I'm doing ?
 

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Discussion Starter #8
Thanks Jellyhead
After a ride, I just feel with my hand.
If the tyre is too hot, then I pump it up a bit when it is cold.

After the ride home today, the rear was much warmer.
I played with the dampening before I left, so it is that or just that it was warmer in the afternoon.

Either way, I just like fiddling with the crappy suspension and tyre pressures.
Just when I think I have it, I don't, so I am actually quite clueless ?

Hopefully someone at work sees me fiddling with the suspension and tyres and thinks I know what I'm doing ?
There's too many bikers at my work for to get away with that, they'd be coming over to put their sixpence worth in lol
 

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I check the pressures before I ride for the day, so the tyres are as cold as they'll ever be that day... ;)

Since putting Kineo Tubeless wheels on my bike they've not lost any air at all....
 

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I run my Karoos at 30psi front and back off-road.......
 

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s OEM
I run my Karoos at 30psi front and back off-road.......
I run my Karoos at 30psi front and back off-road.......
Hey Guys ! I too have been playing with the tire pressures on my '17 Racer. (OEM supplied Metz) What I shoot for on our race bikes is tire temps but I start out looking at two things; pressure increase and how the running surface looks.
I kind of started out looking to get a 9% to 10% increase in the front and a 10% to 12% in the rear. I got close to that at the rear (I am using the whole tire except maybe 1/16" of sidewall) when I started at a rear pressure of 36.5 PSI. This said the tire has never felt hot and it does not look to be really getting up to temp. On the front I am down to 33 PSI and still only got a 2.8 # raise in pressure.
I will grab our pyrometer and see what kind of temps I'm generating. My guess is that I'm under 150 * . I'm trying to get some idea of what temps these tires like but have as yet not found any numbers.
Our Pirelli race tires start to really work at about 180* but do remember: each manufactures tires (and even each model within a brand) are different, I only care that the tires are good for the weekend and we check them every time we run the bikes.
Just FYI what I lok for is at least 3 or 4 PSI increase, if I don't get that I let some air out and try again. If I get much more that 7 PSI then I figure that I started off too low and I increase the pressure by 1 PSI and again run the bike.
Starting out at 33.5 front and 36.5 rear the increases look good but how the tread surfaces look is not very pleasing when I get some temp numbers I'll get back to you all.
When discussing this kind of thing my friends in Europe tell me that the different governing bodies are now starting to enforce a MINIMUM tire pressure (I think it was something like 22 or 24 PSI) because the teams just kept lowering the pressures and the tires just kept getting stickier. Now they don't care about wear as long as the things last a full race but it is something to thing about.

Cheers
Rich
 

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Thanks for the good info Rich46.
I don't have a pyrometer, but will certainly check out the increase in tyre pressure when temp goes up.
 

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Thanks for the good info Rich46.
I don't have a pyrometer, but will certainly check out the increase in tyre pressure when temp goes up.
I did forget to mention two things in regard to my R nine Racer. One is that I've taken quite a bit of weight off the motorbike (aprox. 44 #'s) the other is that I always use nitrogen in the tires rather than air. The NI is used mostly because (remember air is almost 80% NI to begin with) it tends to be water free. Because water will really expand in volume under heat using it tends to make your pressure readings and changes less trust worthy.

I only mentioned these things because it may make some folks numbers not jib with mine but the overall ideas will be the same. Your bike may end up needing less air (from a compressor) than I would need NI from a bottle to get the same reading and change results.

Anyhow just thought I'd mention this so as to not mislead anyone.

Cheers
 

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I always thought that Nitrogen was a myth ?
But what you say makes sense.
 

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I always thought that Nitrogen was a myth ?
But what you say makes sense.
If you only street ride and have a good compressor with a really good water trap then I think you'll be just fine. When we go to places like Phillips Island or the IOM we have a little (and only used for overseas trips (we are in the States)) one that we just keep for that. It has two good traps and being brand new the air seems to be very H2O free. So that is kind of a reasonable test. I wouldn't be using the air from the local gas station.

I totally agree that for the most part paying a Dealer or Shop for Ni when having tires mounted is just a profit line for them ! If you don't keep going back for more Ni to support what they put in, in the first place then paying for it when getting new tires is totally crazy as every time you add air you dilute what they started you off with.

Cheers
Rich
 

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I recently spoke with an accomplished R12GSA pilot*. He swears by low pressure for on/off road travel. Typically he runs 25psi/1.7bar. For extreme off-road competition, he's used 15psi/1.0bar. He's never popped the bead, ymmv. I'll be trying significantly lower-than-factory pressures when I ride the UrbanGS off-road. Cheers, M

* https://www.taaraadv.com/
 

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I recently spoke with an accomplished R12GSA pilot*. He swears by low pressure for on/off road travel. Typically he runs 25psi/1.7bar. For extreme off-road competition, he's used 15psi/1.0bar. He's never popped the bead, ymmv. I'll be trying significantly lower-than-factory pressures when I ride the UrbanGS off-road. Cheers, M

* https://www.taaraadv.com/
Yep, when I was young and full of piss and vinegar we did Barstow to Vagas every Thanksgiving. Road everything from DR 350s, DR650s and a flock of XRs never used over 16 PSI usually around 14. Wouldn't go anywhere as low as that on the street. I have a well set up RC51 that is a track day and once in a while Sunday Morning ride bike.
The bikes works well but I never get below 24 PSI in the rear and 28 in the front. Even in cool weather I get any lower than that and the temps and pressures go off chart and stop working well.

Rich
 

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Yep, when I was young and full of piss and vinegar we did Barstow to Vagas every Thanksgiving. Road everything from DR 350s, DR650s and a flock of XRs never used over 16 PSI usually around 14. Wouldn't go anywhere as low as that on the street. I have a well set up RC51 that is a track day and once in a while Sunday Morning ride bike.
The bikes works well but I never get below 24 PSI in the rear and 28 in the front. Even in cool weather I get any lower than that and the temps and pressures go off chart and stop working well.

Rich
Hi Jellyhead,

As I said I would I'm getting back with some more info. Did a real hard 130 mile (do need to stop for fuel) run on Sunday . The ambient air temp was in the high 70's and low 80's. I started out where I had planned at 33.5 in the front and 36.5 rear. Same pressures I had tried before.

This time front got to 37.0 and the rear 39.5. Very close to what I had seen before. When I went to the pyrometer I was totally shocked at the temps (you should hit the tire in three places L/side, middle and R/side I didn't really bother with that as the last 2 miles to the shop are fairly straight.) Front tire was at 145 * the rear at 153* (rear being the drive tends to run a bit hotter) considering that it was a warm day. I would have thought that I would have seen mid 160's and I was in hopes of mid 170's.

The tread part of the tire doesn't even look like it's really working. This said the motorbike felt stable, didn't slide, and in fast transitions was working great. Probably the most important it did inspire confidence.

Never one to let things just be good, next Sunday I'll try doping the rear again to 35.5 and try it again. As I said before the front came up just fine but the rear could still use a bit more pressure raise.

Funny side bar here is I always check the tread depth with a gauge when the tires cool down (hoping I can find an excuse to buy some sticker hoops) and there is almost no wear on the OEM Metz that came on the Racer just amazing wear with these tires. And this is all with me showing little mercy to these tires except proper maintenance.

Cheers
 

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Discussion Starter #19
Interesting stuff. I never ride hard enough to get my temperatures up that high (UK temperatures seldom allow this either lol), so my bike is happy at lower pressures, i might even drip another psi or two yet
 

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Hi Jellyhead,

As I said I would I'm getting back with some more info. Did a real hard 130 mile (do need to stop for fuel) run on Sunday . The ambient air temp was in the high 70's and low 80's. I started out where I had planned at 33.5 in the front and 36.5 rear. Same pressures I had tried before.

This time front got to 37.0 and the rear 39.5. Very close to what I had seen before. When I went to the pyrometer I was totally shocked at the temps (you should hit the tire in three places L/side, middle and R/side I didn't really bother with that as the last 2 miles to the shop are fairly straight.) Front tire was at 145 * the rear at 153* (rear being the drive tends to run a bit hotter) considering that it was a warm day. I would have thought that I would have seen mid 160's and I was in hopes of mid 170's.

The tread part of the tire doesn't even look like it's really working. This said the motorbike felt stable, didn't slide, and in fast transitions was working great. Probably the most important it did inspire confidence.

Never one to let things just be good, next Sunday I'll try doping the rear again to 35.5 and try it again. As I said before the front came up just fine but the rear could still use a bit more pressure raise.

Funny side bar here is I always check the tread depth with a gauge when the tires cool down (hoping I can find an excuse to buy some sticker hoops) and there is almost no wear on the OEM Metz that came on the Racer just amazing wear with these tires. And this is all with me showing little mercy to these tires except proper maintenance.

Cheers
In the old days, we were told to look for a 10% increase between cold and hot PSI.
It looks like you have achieved this.
 
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