R65LS "tube"

[jgp1854]

had the local BMW dealer install two new Lazertec's on the LS, which also include two new Metzler tubes.  Rode the LS home some 160 miles, and parked it.  Several day later, went to get on it and the rear tire was flat......I could not find any signs of exterior puncture whatsoever.

The rear tire was removed and taken to a local tire shop that sells a fair amount of MC tires etc.  They found the stem had pulled apart from the tube??

They installed a new tube, but they also put a "nut" on the INSIDE of the rim, and a nut on the exterior.  I've never heard of a nut on the inside.  Needless to say, you cannot check the air pressure without remove the nut that is on the exterior.  

My questions are:

Has anyone experienced the stem pulling away from the tube?

Has anyone heard of a nut being installed on the inside of the rim?

I'm taking it back (via a trailer) to the BMW dealer that installed the new tires and tubes to have a new tube reinstalled by them.  And get their "spin" on what happened causing the stem to pull away from the tube.

Feeling darn awful lucky!!!

Jim

[Bob_Roller]

I've heard of that being done before, but from what I've heard and read, it's not a common practice .

It almost sounds like the tube wasn't installed properly, the valve stem not lined up with the hole in the rim .

With the nut on the inside of the wheel, how much valve stem is protruding past the nut on the outside of the wheel .

We've had a few members with not enough valve stem coming through the wheel, to where it was difficult to get air into the tire, the air chuck bottomed out on the exterior nut, before the air chuck could depress the valve core and allow air into the tire .

[nhmaf]

It is not correct to put a nut on the inside of the wheel rim.    The nuts on the stem are meant to be on the outside of the wheel.   IT is supposed to be screwed down to the outer wheel surface to hold it in place while installing the tube and when inflating it with air.   Otherwise, it is back off up to the valve stem cap to secure it (jam nut).   This makes things especially problematic on the LS wheels, which have a deeper "channel" inside and a thicker rim on the outside which the valve stem must pass through.   Putting a nut inside not only makes the tube press hard against the nut and possibly chafe it, it prevents the stem from going all the way into the channel/hole that it is supposed to - you may get lucky and still be able to get your tire inflated, but it will probably be a close call - the Metzlers fortunately also have an ever so slightly longer stem than another brand of tubes I had tried.

[bruce_launceston]

You can run the LS rims tubeless.

My rear has always been tubeless (except from the factory I guess).

I only run a tube in the front because I had a slow leak that I could never seal, probably alloy porosity.

[jgp1854]

Bob, NHMAF,

Bob, you are spot on, I cannot put air in the tube w/o removing the locking nut.......

NHMAF, your precise directions is exactly what I'm will be showing the dealership this week, when I arrange to have the second tube removed and another Metzler tube installed.  

I for one, am getting tired of the lack of quality work being done at BMW dealerships.  One thing they are good at is charging for their work!

Thanks

Jim

[nhmaf]

Some more links on the topic on other websites, including the venerable snowbum's:
http://bmwmotorcycletech.info/section6.htm (scroll down to #9 or thereabout, or wade through the whole page)

http://bmwmotorcycletech.info/section5.htm (General tire info, recommendations, etc)

BMW MOA forum thread:
http://www.bmwmoa.org/forum/archive/index.php/t-5629.html

And a bit on the topic from Duane Asherman:
http://w6rec.com/duane/bmw/air/index.htm

Basically, you want the nut on the outside, and ideally, not tightened down hard against the wheel rim for normal running to avoid/reduce possibility of tearing the stem from the inner tube if the tire/tube slip on the rim (though I personally have never seen this happen - I suppose maybe if you are doing burnouts, etc. with your bike it is more likely to happen)

[suecanada]

I am probably the person everyone remembers having problems getting air into my tires And checking the pressures because the valve stems were too short. I had the INSIDE nuts removed and it is much better. I still end up taking off the outside nuts to this day. I find the rear tire harder to fill up or check because of the little distance between the rim and the inside wheel hub. If ya want to use one of those modern flip type nozzles on a bicycle pump, the rear wheel doesn't have enough room to toggle the locking device up. What ever happened to the nice screw on nozzles on bicycle pumps! Sigh!
I use a cycle pump and gauge from Bestrest Products but wish it was less complicated. The pencil gauges work of course.

[jgp1854]

Okay a new Metzler tube installed at the BMW dealership today.  They were at a loss why the valve stem pulled out.....They did however, inflate the tire to 41 psi?  I questioned the high level and they responded that is what the tire stamped on its sidewall.   The sticker on the LS indicates significantly less than 41psi, something in the vicinity of 30F/29R.  

Who/what is correct?  

Does it make a difference if the OEM rims are "tube" rims and the tires installed Lazertecs are tubeless.

Using tubes in tubeless tires have any adverse impact?

Thanks for all the insight

Jim

[Barry]

The sticker on the LS indicates significantly less than 41psi, something in the vicinity of 30F/29R.

Who/what is correct?

Neither.

I would go to the tire manufacturers website and they will list pressures for your bike:-  2.2 bar front 2.3 bar rear. They should be read as minimum pressures and they will be safe. I use them.  Some here will recommend pressures a little higher for better handling.

If you really want to confirm your chosen pressures are correct ride the bike hard and then measure the pressures hot. The front should rise by approx 10% and the rear by 20%. If they rise substantially less they were too high cold and if substantially more they were too low cold. I've done this using tire manufacturers cold pressures and get reasonably close to those guidelines.


When using tubes in tubeless tires the manufacturer will usually recommend a reduction in maximum speed rating of the tire by one grade. That's not a practical problem with H rated tires on an R65.


http://www.metzelermoto.co.uk/web/fitment/metzeler/selectSearchTyresForm.do?mySelectActived=confirm&myEntryPoint=%2Ffitment%2Fmetzeler%2FhomeMotoFull&brandVehicle=8231&modelVehicle=196053&versionVehicle=409743&consent=Y#fitmentanchor

[Bob_Roller]

I routinely run my Metzlers at 40 psi, no problems .

I service them to 40 psi, then let them go down to 35 psi, then reservice them .

Tires seem to lose pressure fairly quick with the high temps I experience here, as compared to our 'winter' here .  

It 'seems' to me at least that the steering is a bit 'quicker' at the higher pressures .

Try running 35 psi front and back and see what you think .

Experiment with pressures to where the bike handles the way you like it .

There's no right or wrong with tire pressures, it's what works for you .

[jgp1854]

Members,

As I have stated previously, this forum and its membership is the R65's best friend.  You answer questions directly without a lot of fanfare.  You individual knowledge is so valuable to owners like me.  

Once again I thank each of you for all you do for the rest of us.

Warmest regards

Jim

[bruce_launceston]

A professional tyre installer inspected my LS rim and confirmed that it has the necessary shape to lock in a tubeless tyre.
The tyre pressure on a tyre sidewall is usually the maximum not the recommended running pressure.
That said modern tyres should be run at higher pressures than that stated on the 30 year old sticker under the seat. As others have said check the tyre manufactures recomendations. I run 38 psi in my rear tyre as I am often two-up (but would run 36 as a minimum).

[Barry]

Personally if I had LS rims I would also run tubeless purely from the point of view of less unsprung weight. It's just a more elegant solution from an engineering point of view.

I agree about the side wall marking being the maximum pressure and not the recommended. Tires pressures are almost like oil threads or tire choice threads in that that there is no consensus on what pressures to run except that everyone agrees the under seat pressures are far too low for modern tires.

I run the manufactures pressures as a minimum. Like Bob I inflate to couple of PSI over so that they don't fall below the manufacturers recommendation by the next check. I'm probably in the minority though in not using pressures way in excess of the manufactures recommendation.

One reason is that tires are part of the suspension system. They have a spring rate just like the main springs and you can calculate their contribution to the overall spring rate of the suspension system. And I need that contribution because my regular commute road surface is rough and full of pot holes !

Another is the 10/20 rule which is designed to check that the tires are reaching an optimum operating temperature for best grip.  If the cold pressure is too high the tires will not flex enough to heat up as they should.    

Lastly I'm a lighter than average weight so feel I don't need to go too much higher than recommendations although I do add pressure when loaded or carrying a passenger.  

[tvrla]

I'm with Barry on this. But have no idea why the original tires could run lower pressures than currently. I had always run the higher pressures, which give better fuel economy but less grip and a harsher ride. After this topic came up on another forum, I tried lower pressures and like them much better.

Also, the data I've gotten said the front should increase by about 8% and the rear about 12%.  Since my gauges can't read that fine, just average it out to 10%. I haven't checked to see if I'm in the ballpark, but like the feel of 30 front, 32 rear.

[Barry]

Starting with tire manufactures pressures of 2.1 bar front and 2.3 bar rear when I checked my pressure rise against the 10/20 rule I got 9.5% rise on the Front and 17.4% on the Rear.  I thought that wasn't too far off given that although it was a long run I didn't ride really hard for the last few miles approaching home because it's not the sort of road where you can do that.

I'm not too pedantic about exactly 10% and 20% but just putting my hand on the tires after a run tells me the rear is hotter than the front so I'm not surprised the pressure rises more.

One thing that confirms the value of using some variation of the 10/20 rule to me is that when bikes are raced on the track they start with lower cold pressures than they would with the same tyres on the road and obviously get a proportionally bigger pressure rise because they are riding harder than us. What ultimately matters to them is the tire temperature when hot and they just wouldn't get up to the correct temperature if they started with the pressures too high.