R12R Tire pressure - owners manual vs dealer recommendation

[BackNBlack]

Perhaps those of you with more R12R miles can assist. What is best tire pressure for solo, no gear loaded on the R12R? I ask because owners manual says 32 Front and 36 Rear, whereas BMW Sales guy suggested 40 front and 42 rear - I believe he was recommending this for optimal tire wear. I'm interested in that, but more interested in quality of the ride - good grip, smooth ride, safety, etc. Appreciate any of your recommendations based on your experience.

Thanks!

BNB

[celticus]

Perhaps I am negligent but I keep mine at the same pressure solo or two up. Heavy load or just my big butt. Around 40 rear and 37 or so front.

Mark

[ka5ysy]

If you look at the tire data, the reason for specific inflation pressures is to give optimal contact patch size based on load etc. Over inflation makes for a smaller contact patch and somewhat less traction. Under inflation causes a larger patch at the cost of sidewall flex that generates heat in the sidewall and tire failure possibilities. Soft tires also may cause handling problems . It is better to be slightly overinflated than to be under inflated.

the motorcycle operating manual recommendation is probably the best information generally, and the tire manufacturers all have consumer lines that can give specifics for a particular tire. They are the best source of that kind of information.

It probably does not hurt to stay at the "loaded" pressure all the time. I tend to use that on my Road Attacks because The Boss hops on and rides with me a lot. Only problem I have noticed is that the rear tire is developing a noticeable flat spot in the center after 4000 miles which is a sign of overinflation as a rule, but I do a lot of fast highway miles. Still lots of tread life showing though.

[mcavotta]

Only problem I have noticed is that the rear tire is developing a noticeable flat spot in the center after 4000 miles which is a sign of overinflation as a rule, but I do a lot of fast highway miles. Still lots of tread life showing though.

Overinflation? Seems counterintuitive, but I'm open to explanation.

I've been wondering what pressure to run as well. Should I be checking with the tires cold or warm?

Thanks!

[BackNBlack]

I always check tire pressure cold right before I go out for ride (I ride once or twice a week) as cold check is the normal owners manual recommendation. On past bikes I have always run my tires at the owners manual recommended cold pressure give or take a pound. I may have to check back with the sales guy again on why he recommended higher.

[iowabeakster]

My dealer (and conventional wisdon) says to go with the higher pressure. Longer tire life, better milage, better handling are the reasons.

BMW recommends the lower pressure to give comfy test rides, hopefully to sell more bikes.

[deilenberger]

My dealer (and conventional wisdon) says to go with the higher pressure. Longer tire life, better milage, better handling are the reasons.

BMW recommends the lower pressure to give comfy test rides, hopefully to sell more bikes.

IMHO - your dealer is fulla'beans (tech-term..)

The manufacturers of the tires likely know a bit more than your dealer, and that's where BMW comes up with the pressure recommendations. It has to do not only with wear/handling but also load-rating.

As far as comfy test rides - well - I ride looking for performance/handling.

Comfort on a test ride is pretty much restricted to how I fit the bike. I haven't noticed a real comfort difference running pressures from about 5 under factory recommendation (inaccurate gauge) to 15PSI over the high-pressure recommendation (dealer set them there..) Not enough difference to be startling... although the 15 over felt perhaps a tad harsh over sharp bumps - it wasn't uncomfortable, just noticeable.

What I did notice is 5PISI under the front tire started to pill up the rubber, and handling was sub-par. It stopped doing that at the correct factory pressure.

I do run a few PSI (5 usually) higher than the single person cold pressure because I've found I have less cupping of the front tire that way (I'm a heavy user of brakes), but that also means I probably have a smaller contact patch and less grip.

[mogu83]

A lot of words but no information.

I think what BlackNBlack was looking for was something like this:

Hi, my name is Harry and I run F38 and R40, because that's what I like.

Anyone else know what their tire pressure is?

[celticus]

I said earlier"Around 40 rear and 37 or so front" but I have been known to ride with them 42 rear and 40 front. What about shock set up? Should that be another subject all together, as it is another subject altogether?
Mark

[mogu83]

What about shock set up? Should that be another subject all together, as it is another subject altogether?
Mark

Good question and I agree with your answer

I thought it would be interesting to know what others were running in their tires. Like the numbers.
I've been around long enough to hear all the theories and read all the articles.
Mark - It seems only the two of us know how much air is in our tires (tyres for DJ)

[qgaex]

2.5 F / 2.9 R

Cheers

qgaex
*whoismetric*

[celticus]

I'll be checking my tires soon for a trip this Friday down to the north Georgia mountians in Suches where we will attened the Festival Of Fives Rally at the TWO campground. Wonderful roads all around. All of the roads are great. The campground is terrific. See the latest Where and When in the MOA for details. Join us.
Mark

[mogu83]

Mark,
Your not going to ride that Hexhead to a /5 event are you. The anti- technology types might burn your bike.
I remember when the /5 came out , it was marketed as the NEW BMW, lighter,improved engine,real horsepower,modern style and better electronics. It took a few years to get off my BSA and save enough for a Beemer. And here we are 35 years later with the same thing. I wonder what will be the latest and greatest in another 35 years (although it will be irrelevant to me).

Here's a pic of my /5 (yes - still have it) at Antietam Battlefield taken this spring. 600 miles on a 36 year old bike and it didn't miss a beat.
I hope the NEW BMW serves me as well but I don't think I'll be riding it for 35 years.

[celticus]

The bunch I hang with are generally too lazy to get up and burn something. A motorcycle anyway.
There are still one or two of them who can beat me on the twisties with their airheads so they don't get too mean.
There will be all kinds of bikes down at Suches this weekend.
Mark

[celticus]

In preperation for tomorrows trip I checked mine, 42 front 38 rear and I'm leaving it that way.
Mark

[Aitch]

My little Service and Technical Booklet says:

One-up front 14.5 psi Rear 36.3

My BMW Motorrad Repair Manual says:

One-up front 31.9 psi Rear 36.3

Anyone else notice this discrepancy?

[deilenberger]

My little Service and Technical Booklet says:

One-up front 14.5 psi Rear 36.3

My BMW Motorrad Repair Manual says:

One-up front 31.9 psi Rear 36.3

Anyone else notice this discrepancy?

Mine doesn't say that.. I rounded them up after looking in the manual, and I used 32/37PSI.

What page do you see that on?

[deilenberger]

Anyone know the rear Conti RoadAttack tread depth?

Measured mine tonight. It appears to be between 4.5-5mm. I'm just curious since I have very close to 5,000 miles on the tires, and someone I talked to over the weekend only gets 6,000 out of a set (Triump Speed-Triple.)

[Aitch]

The tire pressure listing is in Sect 3 page 71 of my Tech. Booklet
BMW Motorrad Order no. 01 47 7 664 947 10.00 2nd edition USA/RF

[AllanCook]

That's weird. My data is on p. 60, and it doesn't look anything like that. It also says 2.2 bar = 31.9 PSI. I think 14.5 must be a typo.

Also, the photo shows a 170 rear tire. Mine's a 180/55 ZR17.

According to my book, the recommended pressure is 31.9 front, 36.3 rear for a single rider with cold tires.

I have the Contis. Do you think there's a different book depending on the tires? Mine was one of the very first imported into the U.S. Maybe that makes a difference?