05 RT Tire Pressure. Did the dealer tell me right?

[eruff]

When I got my '05 RT last Sept., the salesman told me the tire pressure should be 40 psi in the front and 42 psi in the back. I think I asked him about this since I saw somewhere a lower pressure in the front. I think he said "Oh, that's for Europe where all the roads are winding. Here they are mostly straight." Anyway, the bike manual says (back cover) 31.9 psi on the front with one-up up to 36.3 psi for 2-up with luggage. For the rear, it's 36.3 psi for one-up, otherwise it is 42 psi. I weigh 200 lbs. I wish I weighed the standard BMW 170, maybe one day.

 

What should I believe? I've been reading about ABS and all that, and I don't want to defeat my braking or road handling with tire pressures that are too high.

 

Did anyone else get this kind of advice when they got their RT?

 

The tires are still stock, here is the text on the tires

 

Front: Bridgestone Battlax BT020 F 120/70ZR17M/C (58W)

Rear: Bridgestone Battlax BT020 R 180/55 ZR17M/C (73W)

 

I know this is not an exciting post, but I'm starting to obsess about it. Maybe 4 psi doesn't make any difference... I'm guessing someone here has the skinny

 

-Eric

[FIRST_BEEMER]

I think your dealer is wrong. I have never heard 40 psi front for any motor cycle tire. I run 36 front and 38 rear. I have 3 other bike and run 36 front with a 120/70/17 tire on the street.

[Warren_H]

My dealer stressed 36F & 42R under all conditions. I've followed that for over 6000 miles now and don't see any reason to change.

[Bob Palin]

You are going to have to experiment with the pressures to see what suits you, 40-42 is on the high end for solo riding, I run 38-40 on my 1150. It's a question of the type of riding you do, the loads you carry, the type and temperature of roads you ride on. Vary the pressure by 2psi increments front and rear and see what feels best, then you will probably have to increase it a couple of psi to get best wear if that is what you are after.

[PaulW42]

36 front and 42 rear is what is normally recommended over here in all conditions. Has worked well for me with a variety of Boxers over the last 8 or 9 years. I personally find that if the rear drops to around 38, the handling becomes pretty mushy (and the fuel consumption goes up - in fact, this is what alerted me to a very slow puncture a couple of years back. Took me ages to find the cause )

 

Paul

[FIRST_BEEMER]

Well I think I`ll just have to test your Advise and see how it works.

[Ken H.]

I think he said "Oh, that's for Europe where all the roads are winding. Here they are mostly straight."

Regardless of what he said about tire pressure, I would have mentally blown him off as a dip-wad right there!

 

Generally most people report better handling and tire life, at the expense of somewhat less comfy ride quality, with somewhat higher tire pressure than what is recommended by BMW. Their numbers seem to be biased more toward the comfort side of the equation.

 

Beyond that, experiment until you find the combination you like.

[ShovelStrokeEd]

FYI, the factory recommended tire pressures for my Blacbird are 42PSI front and rear. I think that has more to do with the speed capabilities of the bike than anything else. It is certainly not for comfort.

 

An easy test. Pick an inflation pressure, say 36 PSI and go for a ride. Measure your tire pressure after a 1/2 hour or so of riding. If it's up around 40 you are right in the ball park.

 

In fact, I don't bother checking cold inflation pressure. I just check for a hot pressure of around 40f, 42r at my first gas stop.

 

I do believe that the 31.5 PSI front is a misprint. The front end will feel like mush at that low an inflation pressure and the thing will steer like a truck around town.

[FIRST_BEEMER]

Rule O Thumb states 4 psi change from cold to hot.

Any tire pressure label/placard or book gives cold tire pressure settings. Lets not add preference to the mix. I prefer the K.I.S.S. method

[ShovelStrokeEd]

Before you go spouting rules of thumb, get them right. It's a 10% change from cold to hot and really only applies to what race mechanics seek at the track. That it happens to work pretty well for street riding as well is an aside. The cold specification actually comes from that as few race teams have the luxury of bringing the rider in during the race to adjust tire pressure. Daytona pit stops being the exception and even there, they fit a new tire.

 

There is nothing more complex about my method, it is just more precise as the pressure is correct for that day and that load on the bike.

[FIRST_BEEMER]

I never said it was or is more complex.

All tire info is based on cold tire pressures.

Not all riders are track riders and should stick to the basic rules (reccomended/book info) of tire pressure specs.

[Catbird]

I run mine @ 40/40; it works for me.

[ShovelStrokeEd]

I never said it was or is more complex.

 

Agreed, I was refering to another post.

 

All tire info is based on cold tire pressures.

 

Makes no sense as the cold pressure only applies when the bike is parked. Checking tire pressure when warm is far more precise.

 

Not all riders are track riders and should stick to the basic rules (reccomended/book info) of tire pressure specs.

 

Many riders, not just track riders, choose to devieate from factory specification and do so out of knowledge gained rather than just blindly following recommended book information. The point being that the "basic rules" as you so pedantically state them, often do not meet individual goals or needs. I quite often vary my tire pressure to suit the condtions of load and/or intended usage. There is no "one size fits all" perfect tire pressure which is why those who have some knowledge in the matter will vary their pressures from that published by the mfg.

[FIRST_BEEMER]

Ed. It make sense for a base to start. You can`t expect

someone to start at the end of what you or more experienced rides have learned. All recommend setting are base on cold tire pressures. I`m trying to respond to the question without making it more complicated. Basic questions get basic answers

[ShovelStrokeEd]

Last post you said you weren't accusing me of making it more complex, this time you did just that. My system is no more complex and allows everyone to tailor their tire pressure precisly to load and usage. In fact, it is less complex than conventional "wisdom?" in that one need only check and adjust pressure once, at the first gas stop.

 

We are really picking fly poo out of pepper here anyway. Most folks are so negligent of tire pressure as to make this discussion moot anyway. Ask any dealer technician. In point of fact, unless I'm setting out on a multiple tank ride somewhere, I just give the tire a slap while slipping off the fork lock and listen for the ring. I'm usually within a couple of pounds that way and don't worry further about it. I ride every day and, as such, don't suffer from the gradual loss of pressure most folks encounter with their bikes sitting till the weekend.

 

I consider the gas pressure in my Dunhill cigar lighter a far more important check than tires before a trip as I can go far on low tire pressure but can't stand not being able to fire off a good Cuban.

[steve.foote]

Eric,

 

I ran 40/42 on my RT for 40,000 miles without any problems. I went to the higher pressures for better tread wear.

 

If you ask ten different people, you will get 10 different answers, so experiment a little and find a pressure that YOU like between the manual recommended pressures and the max pressure stamped on the tire.

 

Then the next time some asks, you can tell them your preference.

[lexxol]

38/40 seems to work well on my 04 RT. You do have that cool tire gage experiment.

[cjmkerns]

38/40 Works for me and has given me an average 11k miles per tire set (six sets) on my 1100RT. Higher pressures tend to give better tire & fuel mileage and some find the handling better(I do). Cupping on front tires is reduced as well as better protection against front wheel damage from road debris or potholes.

 

You'll find many of those who have been riding these oil/hex heads for a while will run about 4 psi above recomendations front & rear. I'm useing 38/40 solo on my 1200RT and bump the rear to 42 with a camping load.

 

Regards,

 

Carl

[apm]

I run my 12RT with 38 front and 42 rear. No cupping so far with 6,000KM.

[RFW]

Why in heaven's name would you pay attention to what some salesman says when the manual, with tire pressures laboriously researched by the MANUFACTURER tells you otherwise? The tipoff was the idiotic reason given by the salesman.

 

Bob.

[eaglemike]

Interesting.....I can provide considerable objective evidence that the manufacturers are far from perfect, and in some cases wrong. I've seen what seems convincing evidence here on this forum - at least to me.

 

I routinely run higher pressures in the front than the factory recommends. I did this on my FJR - btw, the consensus on the FJR1300 forum was that this was very necessary to avoid cupping. Pressure needs vary, depending on loading, and riding situations. Sometimes a different tire will respond better to a certain pressure than the previous installation. In this particular instance, the dealer suggestion was pretty close to what I run, but his reason seems pretty weak. You should run whatever pressure seems right to you, experiment a little, maybe.

 

Ed's technique seems to be the almost universal rule of thumb............

 

all the best,

 

Mike

[eruff]

In fact, I don't bother checking cold inflation pressure. I just check for a hot pressure of around 40f, 42r at my first gas stop.

 

Maybe the salesman WAS quoting me hot tire pressures that match with what you are saying. The salesman was giving me a machine gunning of information about my new bike...how to get in on the center stand... when to bring it back for servicing... keeping it under 4k RPM for the first 600... what kind of gas to get..... It's entirely possible he said hot tire pressure and I didn't catch that part.

 

-Eric

[ShovelStrokeEd]

Possible but doubtful. BMW salesmen tend to be a bit more knowledgable then the average for the breed, but I have found far too many who are so misinformed that it borders on ludicrous. Follow whatever chunk of advise you find most useful here. It's your bike and you will have to determine what best suits your riding. There are compromises all through the range of normal tire pressures, compromises between traction and wear, ease of turn in and stability, ride and rim protection. All need consideration when developing a plan for tire inflation. The book is, at best, a guideline, as is the maximum cold inflation pressure stamped on the side of the tire.

 

Just to give you a quick expample of book pressure differences, my 2001 Honda Blackbird calls for inflation pressures, by the owners manual of 42f/42r. My R1100S calls for, as I recall, 34f/36r. These bikes weigh within a few pounds of each other and use the same tires. The only major difference between them is that the S tops out at about 140 mph and the Blacbird at over 170. Both of those values are cold inflation pressures. Opportunities to run either bike flat out are pretty slim. I run them both the same way, around 40/42 hot unless I am out running twisty roads all day and then I drop things a bit.