Tyre Pressures

Very true.

 

Hi,
appreciate your comment.
I misunderstood what pressures you were running!
I agree with you entirely about what can happen to tyres at a circuit, it is a fact though that some riders are ill advised and drop their pressures too much, in some cases when they would actually be much better
running nearer standard pressures!
It is a fallacy that pressures should be dropped as a matter of course on a circuit,there are many influencing factors, one needs to know many details before deciding, I'm sure you know this, just wanted to clarify
that I'm not a complete novice on this subject.

cheers

 

I caught some of that fallacy from supposed experts while at Cadwell, hence my comments earlier in this thread. Thanks to all for putting me straight. I have a pseudo track day on Friday, a knee down day at an airport. I'll update.

 

No worries, Gents. Peter, good luck with your upcoming track day. Keep that right foot tucked in. The rear brake apparatus gets in my way and my dragging right boot has become my right turn limiter. It always gives me a start when I forget and it touches down.

Just to repeat (and beat this nearly dead horse), since these threads can get hard to follow; I am the poster who is swimming upstream on the pressures by advocating that we stay close the BMW recommended settings for STREET TIRES such as the Michelin PR4s I have been running.

Lowest pressure I would go on street tires is 35/40. Below that, you will start getting a bit of squirming from sidewall flex (and excessive wear) without getting any real traction pickup benefit. I have had plenty of 'experts' (my fellow instructors) at the track telling me my pressures are too high, but the well-respected USA Michelin race rep and I had nice long chats while he inspected my tires at after a couple sessions during practice on race weekend (we run the CMRA race practice with our track days). He is the one who warned me about going with the usual advice of 31/30. As he put it, that is fine for a 400 lb. race replica, but not so great for a 500+ lb. sport tourer.

For my article on testing the RS (BMW Riders Association "OTL" magazine) I did experiment a bit with pressures & suspension settings (limited as we are with the BMW pre-sets) under his supervision (checking temps, wear patterns). I did go as low as 32/30 as part of that experiment. Lots of squirm, excessive wear, and lap times dropped a little with the associated loss of confidence. So, please understand that my recommendation of 35-36 / 40-42 (cold--68 degrees F) does come with some effort at verification rather than just an automatic response. I have run my RS in the expert group and have kept up with some of the slower racers--that really says a lot for this motorcycle. The limit is NOT the PR4 tires or mfr recommended pressure.

Summary: lowest cold pressure settings are 35 front / 40 rear on street tires--cold being defined as 68 degrees F. You should adjust those cold settings +/- 1 psi for every +/- 10 degrees in ambient temperature. DO NOT make adjustments on hot tires. They must be at ambient temperature. I usually set mine in the morning before the first session. Then after lunch where we skip a session and get over an hour for the tires to cool; I recheck those pressures. I rarely have to make any changes. Note that just checking the air pressure in your front tire can drop the pressure by half a PSI if you aren't quick about it. Also, make sure you have high quality valve caps (the ones with the O-ring inside) to avoid pressure loss during the day.

 

I think some settings like the tyre pressure are personal. I mean someone feels better with a certain setting which could be different from others.
I had some track days with my previous bike and only one with the RS. With both bikes I have to reduce the pressure by 2-3 PSI. The ambient temperature was about 25°C. Those values have been recommended by the track tyre specialist. I remember he said: "every track require a dedicated tyre pressure setting". In my experience, the RS is quite heavy and it is quite difficult to brake. I felt benefits reducing the front pressure down to 32 PSI, anyway this is my personal experience.

Do you think the footpegs are too low?

I had al lot of difficulties with the footpeg. They scrape the track many times.

 

I suggest a read of motorcycle sport and leisure, july, page 41 , tyre test on new Pirelli where product manager Paulo Spagnvolo advised that most riders should stick to manufacturers settings and that "Few riders are really at the level to understand the difference in dropping 3-4psi. They just tend to do it because everyone else does it"
Talk about footprint contact and deformation of tyre, sidewall strength, well worth a read. Also about tyre products for each model, weight and versions.
Also if you really are at that level then maybe a true sport tyre would be better for a track day.

 

It is also safer!

 

So -----and this is no reflection on the dealership. Today had a yearly service and the mechanic obviously follows task sheet, report on tyres, wear etc, pressures set again but unlike my checks at home they are on a bike that has just been ridden an hour, sat outside in sunshine. Instead of a cold check it results in my on board display showing 2.3 2.8 on way home instead of 2.5/2.9 it has been for weeks and on the ride down. I have set to show engine temp and RDC on display as standard.
All in the mind but once I saw low readings I was convinced bike was 'soft' at the front but I doubt, without tpr readings I would have noticed.
rtfm, ...added air to get 2.6 and 3.0 on warm tyres, digital gauge and not bothered to ride again to check, will see again next time it's correct while riding.
Convinced tpm /RDC is a good safety item.

 

Sure especially if you travel for long time and with luggage. It helps to keep under control the tyres which could be destroyed by a wrong setting. As every year, I had my holidays with my bike. I did 4300 km in a week most of them with high weight on the bike and thanks to the RDC, I kept pressure in the correct range 2.5/2.9 and the tyres seem good without any significant sign of stress.

I usually do 20.000 km per year and sometime I don't have time to check the tyres pressure before to ride. It happen that the tyres have been rapidly consumed. In my experience, only 200 or 300 km with the wrong pressure could affect the tyres's life, expecially if you push your accelerator.

 

I'm about the same weight as you...don't know yet what sort of pressures I will run on the RS when I get it but in my K1300S & 650 Wee Strom I run at plus minus 10% above the recommended pressure..imho both bikes handle better and I get better mileage out of the tyres plus better consumption.. just something I do.......

 

When riding canyons with my friends in warm weather (Ducati Panigale, Yamaha FZ 09, I run 35 front, 38 rear. In spite of all the "experts and theory", someone mentioned tire feel as a personal thing. I agree. When I run 36/40 It just feels less in touch and too firm for fast riding. When riding 2 up I do run 36/40 and that seems fine. I'm 175 pounds and prefer the Metzelers over the PR4s because of the excessive syping which is more suited to wet terrain.

 

that is my opinion.... the tyre feeling is personal, I prefer to use a lower pressure to get more feeling on brakeing

Next tyres will be metzeler

 

Yep tyre pressures definitely a personal preference..agreed !

 

Just had the Metzeler Roadtech 01s put on, and absolutely love them.

 

I have difficulties with the footpegs also. I have scraped the pegs too often and have worn the metal off my boots because they are too low. I have been looking for a way to raise them, but most options are to lower them. I'm reluctant to get the SATO Racing rearsets https://www.satoracing.com/rearsets_BMW_R1200R.htm because the reviews say they add too much slop to the shifting. If you or anyone else finds a solution, I would appreciate hearing about it. thanks

 

I've heard the HP/Giles controls increase clearance without raising the pegs (shape). Best I've found so far.

 

Raising your foot pegs won't help, you will find that the foot of your center stand (on the right) will get smaller. Run your shock an one helmet and luggage, that will raise the bike some.

 

Rather than continuing here where discussion would be lost under Tyre Pressures I'll raise another thread for Vario pegs. Interested to collect any opinions especially for raising and rear-setting (not forgetting petey's advice about the stand).

 

You destroy the letter "Rosso"

 

In my Z8, rear 2,6 and front 2,4 If I put less air the motorbike is horrible in curve.