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What's the problem with tire pressure?

Yes, and most are radials. And you really shouldn't put a lower profile tire on a bike designed for a higher profile tire.

That is true. But what I was trying to say was, that when referring to "newer tires with higher pressures", the "newer" could refer to those with lower aspect ratio vs those with higher aspect ratio. A /50 tire (radial) has not been around for THAT long and it usually runs with a higher pressure than a /70 (radial)
 
For many, myself included, the days of "uber-reliable" BMW's is long gone based on those and many other problems.

I disagree. The bike was never "uber-reliable" -- the competition was just crap. It only looked "uber-reliable" when compared against a piece of crap bike that was ready for the junk pile in less than 20K miles. Today the competition makes a bike as good or better than BMW.

And what does this have to do with tire pressure?
 
I disagree. The bike was never "uber-reliable" -- the competition was just crap. It only looked "uber-reliable" when compared against a piece of crap bike that was ready for the junk pile in less than 20K miles. Today the competition makes a bike as good or better than BMW.

And what does this have to do with tire pressure?

I was responding to Kevin. :dunno
 
Tire manufacturer's specifications

Getting back to the original point, the tire manufacturer sometimes suggests a different pressure for their product. Call them and ask. Michelin's representative (800-346-4098) said to use the pressures in the owners manual. Also said that there is no difference in tire life for a solo rider when using the "B" rating Pilot Road 3 versus the other rating.

when I told her how much I weighed and what I usually carried, she said I could adjust the pressure upwards near the "loaded" recommendation.

So I guess my point is that the numbers in the bike's manual are for the original equipment tires and your after market tires might need a different pressure. The tire manufacturers are willing to explain this to you so look up their phone number and call.
 
Originally Posted by WalterK75
I see repeated tire pressure threads and I'm not sure why.
I see repeated "what oil" threads and I'm not sure why because it lists what to use in the owner's manual. Go figure...maybe people can't read. LOL

I'll bet money it's because BMW Motorcyles riders like to talk technical data on forums, and at rallies, and dinner tables, and at church, at work, in bed, while sky diving, while scuba diving even though it just sounds like a lot do air and bubbles on a respirator... Well you get the idea.
 
I'll bet money it's because BMW Motorcyles riders like to talk technical data....while scuba diving even though it just sounds like a lot of air and bubbles on a respirator...

Sometimes it sounds like that even when you're NOT under water. :laugh
 
Originally Posted by WalterK75
I see repeated tire pressure threads and I'm not sure why.
I see repeated "what oil" threads and I'm not sure why because it lists what to use in the owner's manual. Go figure...maybe people can't read. LOL

I'll bet money it's because BMW Motorcyles riders like to talk technical data on forums, and at rallies, and dinner tables, and at church, at work, in bed, while sky diving, while scuba diving even though it just sounds like a lot do air and bubbles on a respirator... Well you get the idea.

+1 for sure. we all like to think we know best, or it has been like that for 40 years whilst I was racing etc etc, but the reality is we probably don't. Reading manuals is no where near as much fun as arguing on the forum
best regards
Paul:whistle:whistle:whistle:whistle
 
I'll bet money it's because BMW Motorcyles riders like to talk technical data on forums, and at rallies, and dinner tables, and at church, at work, in bed, while sky diving, while scuba diving even though it just sounds like a lot do air and bubbles on a respirator... Well you get the idea.

It's not unique to BMW riders. I see the same happening in other forums.
 
Originally Posted by WalterK75
I see repeated tire pressure threads and I'm not sure why.
I see repeated "what oil" threads and I'm not sure why because it lists what to use in the owner's manual. Go figure...maybe people can't read. LOL

I'll bet money it's because BMW Motorcyles riders like to talk technical data on forums, and at rallies, and dinner tables, and at church, at work, in bed, while sky diving, while scuba diving even though it just sounds like a lot do air and bubbles on a respirator... Well you get the idea.

WELL, to carry on in the "technical data RE: tires/air pressure" vein....

AND, since I couldn't figure out a way to squeeze
Dyna Beads
into this discussion...
:wave



What affect, if any, do suspension adjustments OR maladjustments have on tire wear (assuming "correct" tire pressure levels)?

The reason I ask:

At the beginning of the summer, I got a new pair of PR3s on my K1200, which I bought used, and so far I have not set the suspension or changed it in any way from where it was set by the PO when I got the bike over 1 year ago. The dealership inflated my new [rather expensive] tires to "36 front, 42 rear". So far, I have tried to be as careful as possible in maintaining these pressure levels- yet, it APPEARS that the front tire is beginning to show a bit of a "ridge" to the left side of center (if you were sitting on the bike). This, after "only" a couple thousand miles.

Uh... WTF? Over.

Could it be that the suspension is NOT set for my weight/riding style, and even tho I am trying to be careful about air pressure, it's causing oddball wear pattern(s) on my front tire?
 
it APPEARS that the front tire is beginning to show a bit of a "ridge" to the left side of center (if you were sitting on the bike). This, after "only" a couple thousand miles.

Sounds as though we may be going into the road camber discussion as a cause for the left side (from rider's perspective) wearing, although I'm not sure what is meant here by a "ridge." I would have expected tread wear. Would it be possible to get a picture of this?
 
Sounds as though we may be going into the road camber discussion as a cause for the left side (from rider's perspective) wearing, although I'm not sure what is meant here by a "ridge." I would have expected tread wear. Would it be possible to get a picture of this?

http://forums.bmwmoa.org/attachment.php?attachmentid=42052

Here's a pic rangerreese posted in the "carbon black" Tire Mystery thread, that clearly shows a "ridge" like I was describing on my front tire. In this photo, there appears to be a "flat" spot at the tire's center, looks about 1&1/2" wide, with similar "ridges" on each side.
On my own front tire, this was only just beginning, and ai saw it in late afternoon sunlight, as the low sun shone across my front tire.
I adjusted my pressure slightly and since, this appears to have eased off on my own front tire.
I had found that I had actually inc
Erased my tire pressure above the 36 pounds and probably had 38 or so pounds of oressure in the tire.

So meanwhile, nobody really addressed my question about suspension adjustments and whether a incorrect suspension settings may cause tires to wear badly?
 
that tire pic looks indicative of 2 things-
1) too much vertical riding.. finding lots of curves should resolve it. In extreme cases, you might need to move to NorCal, central CO or other such twistyroad states.
2) tire pressure too high. fix is obvious.

some of that center flattening is inevitable, as even the twistiesroad states may require too much vertical riding (by percentage of road time).
 
Folks should really take in one of the tire manufacturers presentations at a rally. They, the engineers, all say the same thing, inflate the tires to the manufactures specs as outlined in your owners manuals. All the writing on the tire ie: 42 lbs cold, 900 lbs load, is saying is that is the maximum load & cold pressure that tire is designed to handle.

Yes you can put more, yes you can put less air etc but to say that we know more than a tire company that spends millions on testing is a bit far fetched. I can tell winter is coming on.
 
From a real scientist (my Ph.D. proves that) and racer (cages for lots of years)

Nitrogen does indeed have a lower mass than oxygen BUT oxygen does indeed penetrate rubbers better than nitrogen. There are two reasons racers use nitrogen (sometimes)- they are that it is dry and that a tank can be smaller and easier to haul/use (eg no electricity needed) than a compressor (in some sizes). Nitrogen filled tires hold pressure longer and have predictable pressure changes with temp. (Gases often penetrate materials in ways not so obvious to the untrained. For example, at low temps, carbon dioxide walks through many common plastics very rapidly but its slow enough at higher temps above liquid that soda in plastic bottles has a several month shelf life). Ordinary low pressure compressors make "wet" air (which is why they put drain valves on the tank) and while there are compressors that makes dry air, they either make it at very high pressure or are too large to be practically portable- and are expensive either way. The rate oxygen penetrates rubber is low enough to be of no importance at the track so any dry gas works about as well as a tank of nitrogen- eg a tank of compressed air gives the same result for short term use.

Liquid water makes gaseous water in proportion to temperature. Tires in race use will have carcass and tread temps that will usually be above or at the boiling point of water (note that the boiling point- the conversion temp) goes up a few degrees as pressure inside the tire increases (this difference is in fact the principle behind industrial steam sterilization times)- above boiling point converts all of the low volume of water drops that came in from the compressor to vapor and causes a step change in pressure. Race tires on cages start at much lower pressures than street tires (often below 20 psi) so the boiling point of water inside the tire is several degrees lower than for a street tire.
Street use tires will be below the boiling point of water but especially on hot pavement will get hot enough to vaporize some or all of the water depending on how much got in.

I don't consider the advantages of nitrogen to be worthwhile for street tires. Air is 80% nitrogen (approx) anyway, tires don't get as hot as when at the track, and I've got to check pressures fairly often anyway given the small volume of bike tires. Seasonal or other temp changes especially impact readings. When I have nitrogen or high pressure compressed air handy I'm happy to use it but I won't go out of my way (or pay $5) for it for street use.

The high temps of track use raise other sorts of issues not very relevant to street use- like flow of sealing washers that can create leaks, utility of various patch methods (most are dubious at best for race hot tires though I admit to using such when I had no other option) , heat cycle determination of tire life (race tires become effectively worthless long before they wear off the rubber surface and the balance of prime use time vs performance is often a deciding factor in races), etc etc.. Racing rubber in competition conditions is very different from street rubber to the extent that if you have only street tire experience, you haven't experienced anything very relevant to it.

Oh- I do ride a Honda (recently acquired Transalp) as well as a mess of BMWs ...
 
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