The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Bob_Roller on October 22, 2009, 08:50:11 AM
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I had the tires replaced by Southwest Moto Tires in Tucson yesterday .
I dropped them off at 0900 and came back at 1130 to pick them up .
I was told there were no tubes installed, even though the Metzeler tires that were on there, were not a tubeless type .
So I now have a set of Metzeler Lasertec tires without tubes .
I checked the maintenance log that I got with the bike, and found an entry, that the original owner couldn't find tubes that allowed the valve stem to protrude through the rim far enough .
Not the first time I've heard that comment from members here .
I guess I'll see what happens, not overly comfortable with this set-up, but the old set of tires was worn out, and were still holding air pressure .
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There's a thread going on Boxerworks now about this subject. I contributed my typical pedantry, but that's about it. I have no idea if our wheels can hold a deflated tire on the rim as we ride.
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The shop told me, if I wasn't satisfied with the set-up, they would install tubes, for only the cost of the tubes, no labor charge .
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I'm sticking with tubes in my LS wheels. The metzler tubes' stems do stick out far enough as long as you don't leave a nut on the stem inside the tire/inside the wheel rim - I think that it the no-no/problem. While they don't stick out super far, it is certainly far enough and I haven't had a problem.
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I think, given the choice, I would run LS wheels without tubes before I would snowflakes.
This is just from stuff I have read over the years.
But I don't mind having good, natural rubber tubes in my tires, at all.
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I have discussed this with my tyre tehnician (a biker) and he checked my LS rims when we had a tyre off and he said the rims are designed for tubeless tyres. This rim was from my '84 LS, I don't know if the earlier years had the same rim profile but a good tyre technician should be able to tell as there is an extra lip in the well of the rim.
I have always run them tubeless but now have a tube in the front due to a very slow leak, probably have some porous alloy.
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Check out the service bulletin "R65 and R65LS tires" which implies LS wheels have the 4 deg slope on the rim required for tubless tires.
Not sure if the first link direct to the document will work. If not try the the 2nd and do a search.
https://www.bmwmc.net/getBulletin.asp?id=1758&a=r&doc=2044%2Epdf
https://www.bmwmc.net/bulletinsearch.asp
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Barry - the bulletin does say there is a 4 degree slope but goes on to say that it is possible to damage the TUBE when mounting Michelin tires. It doesn't say mount them tubeless.
To me that says the rim was designed to use a tube.
YMMV but I would continue to use tubes in my tires.
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The 4 Deg slope is the sort of design feature that is found on tubless rims that's all I was saying. I agree you will never get BMW to admit they were suitable for use without tubes.
Admitting that they are not suitable for certain makes of tires suggests they are not exactly well designed for tube type tires either.
We all know that some makes are more difficult to pop the beads in place than others. This is what the bulletin is concerned with. Who's to say it's only Michelin tires that have the potential to weaken the tube ?
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I'm kinda 50/50 on my '81. Tubeless on the rear and a tube up front. The tubed tire is the one that drops air pressure (2-5 psi) every couple weeks. Monte
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I think the debate will always be split.
In the tubeless corner we have:-
Lower unsrung weight.
Holds air pressure much better
Less prone to rapid defation in the event of a puncture
Maybe potential for easy get you home puncture repairs
Should be fitted to the correct rim profile
These qualities mostly improve safety
In the tube corner we have:-
Higher unsprung weight especially with natural rubber tubes.
Regular inflation needed especially with natural rubber tubes
Potential for rapid deflation in the event of a puncture
Road side repairs are always a challenge
BMW bulletin says excessive mounting pressures can weaken the tube
Rim profile not considered an issue although in the event of a puncture I can't see how a tube type tire is no more likely to stay on the rim than a tubeless
Many of these qualities have the potential to reduce safety
On the whole the tubeless tire is the safer and more elegant engineering solution its just a shame our rims are a half way house between tube type rims and tubeless rims altough it seems from the bulletin that maybe the LS rims are a little more than half way.
Well if nothing else one thing weve learnt from Bobs involuntary experiment is that even running a tube type tire without a tube is not actually guaranteed to fail.
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I bought my R65LS in May of this year, its my first BMW.
It came with tubes in, but am I safe to assume that the rims are suitable for and that I can fit tubeless?
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I bought my R65LS in May of this year, its my first BMW.
It came with tubes in, but am I safe to assume that the rims are suitable for and that I can fit tubeless?
Hey, folks! A newbie!
Welcome, Linc. Ride on up to the "General Announcement" section and share with us an intro 'bout yourownself. If you've been lurking for awhile, remember that we love photos of your bikes. Wife or girlfriendis OK, too, as long as Justin is napping. ;D
Monte
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Just to add, that the Lasertec tires are classified as tubeless tires, it's molded into the sidewall .
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Some good points. I think what would really do it for me would be some sort of engineering standard in the form of a document or measured drawing that outlined the specific design required for a tubeless rim. The sort of thing a machinist would use to cut or measure the bead profile. I have tried on several occasions to find something on the interwebs but always came up against a 'pay for subscription' professorial data base. I'm looking and will continue to seek some type of industry standard parameters. A measure and compare exercise could set this to rest once and for all.
For what it's worth, the tube stems on my LS wheels do not seem a proper fit either and I have suspicions that putting tubes on these rims has more to do with lawyers than any piratical measure.
If anyone comes across such a design standard from a legitimate standards body please send it to me. I'll happily dismount my tires to take measurements.
rich
Lookin' to trade my under seat patch kit and irons for a plug kit.
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It came with tubes in, but am I safe to assume that the rims are suitable for and that I can fit tubeless?
LP you have to make up your own mind on this one as we all do. I wouldn't presume to advise anybody on a safety matter for obvious reasons. I do like to debate it though. This particular debate has being going on for 30 years now so there's little prospect of a definitive concensus anytime soon.