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Topic-icon '89 GS: Air Leaks Around Front Spoked Wheel

  • jarthur
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3 weeks 4 hours ago - 2 weeks 4 days ago #5890 by jarthur
I have a 1989 R100GS with spoked wheels. I had a dealer put on a set of Metzler Karoo Street tires. The rear is holding air, The front stopped holding air after a few months. I tested the wheel/tire while the tire was still on the wheel and there were several small leaks at various (random) places around the wheel (bead of the tire). I took the front wheel back to the dealer who said there was corrosion on the wheel, the tire wouldn't seal and recommended putting in a tube which I authorized.

The bike always is kept in the garage and it is not subjected to temperature swings here in the Sacramento, Ca. area.

Is this "normal?" Is there something that could be done to the wheel so I can run the tires tubeless reliably (which is my preference? Should I put a tube in the rear to be safe?

Appreciate any advice.

Best,

Jack
Last edit: 2 weeks 4 days ago by Wobbly.

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2 weeks 6 days ago - 2 weeks 4 days ago #5893 by Wobbly
Replied by Wobbly on topic '89 GS: Air Leaks Around Front Spoked Wheel
• Your dealer is correct, it's the bead portion of the wheel that allows the tire/rim assembly to hold air. But that's not the only place, the valve stem is also a place of high importance. I'm also not aware of any tire mounting product that seals the tire to the rim, although there must be something. However, there are numerous products that can be used to seal the valve stem in place. The main difference between the 2 being that the valve stem can be allowed to cure before pressure is applied, whereas the tire has to have pressure applied quickly after mounting to "seat" the tire.

• While I can certainly understand how pitting in the bead area might form a non-sealable void and allow air to escape, it's also just as likely that the installer scuffed up the opposing portion of the tire during installation, creating the same type divot in the rubber of the tire. So my question at this point is, "Did you see this void ?"

• Although aluminum can indeed corrode, one of the chores of the designer is to choose alloys that are impervious to corrosion, or at least less likely to have this issue. Now of course, dim witted customers can totally outwit the design engineer by stunts such as riding the bike in ocean salt water. In cases like that, all bets are off !! Which is all to say, as a design engineer I can believe it. As a long-time pro dealership mechanic who's changed thousands of street and dirt bike tires, I've never seen it.

My thoughts...
• The dealer has expectations of the staff, and each job has an approximate time allotted to it, because that's the only way he can quote fixed prices for "small jobs" like this. Removal and installation of a tire... probably 15 minutes per wheel. 20 minutes with balancing. So your tire installer really doesn't have the time to do much more than wipe the inside of the rim down, which is done to remove dirt and look for metal barbs that might cut the tire as it's being installed on the rim.

Once corrosion is detected, the rim really should be thoroughly washed (and maybe even treated with something) to remove the corrosive compound and stop the corrosion's advancement. That's the kind of care you and I would take, but this is a commercial setting and the installer is on a time schedule. But the dealership's guy also has a completely different view point. He's thinking, oh boy! This guy is going to need a new rim at the next tire change ! Job security !!

So the bottom line is this: You should consider changing your own tires. Tires and wheels contribute more to your riding safety than anything else. So personal tire and wheel maintenance is closely akin to packing your own parachute.

• Something else struck me as I read this, and that was the level of expectation. Admittedly I live in Georgia where in the last 7 days alone, we have seen temperatures swing from the low 30's at night and into the mid-70's during the day. But knowing that tires pressures are directly responsible for rider safety, steering control and braking ability, I would never ever dream of leaving my house without checking the air pressures in my tires. Hell, I don't even take the lawn mower out without checking the tire pressures !! (Maybe I'm just over cautious, having fixed so many motorcycles involved in bad accidents. Maybe it was that one wreck, that had to have flesh removed from the engine ?) At any rate I'm morally opposed to having anything less than complete control of any motorcycle I ride... which for me mandates regularly checking the tires for cuts and tread depth, daily pressurizing the tires, regularly changing the suspension fluids, and monthly checks of the braking system.

So the bottom line here is maybe you ought to simply check your tire pressures more often. Air is small molecule, and it escapes fairly easily. Maybe expecting a low volume high pressure motorcycle tire to behave the same as a high volume low pressure automobile tire is an incorrect assumption. Maybe the purchase of one of those Bluetooth tire pressure kits is in order. That way you could simply check your phone ap before you crank up. Whatever form it takes, it simply seems like a greater level of tire care may be called for.

Just my 2 cents.

Don't hide 'em, Ride 'em !!
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Last edit: 2 weeks 4 days ago by Wobbly.

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2 weeks 6 days ago #5894 by 8166
On a ride last summer, we found a very long and very poorly maintained road to enjoy on our GSs. By the time we got to the next town, one of the fella's rear tire was losing air. Pumped it up again and got to a shop, and when the tire was dismounted we found that part of the bead had been sliced during installation. We removed the loose part and the tire sealed fine.

I've got a LOT of miles on aluminum BMW wheels, and I've never seen any kind of corrosion on the bead areas. What I have seen is a heavy build up of old rubber and tire mounting lube, and gouges left by ham fisted morons using screwdrivers for tire irons. I'm with Wobbly in wanting to dismount that tire and have a look for myself. If you do, take some photos of what you find and post 'em here.

I've also had conversations with the Heidenau tire rep that their K60 Scout tire sometimes has sealing issues when mounted on the front of an R100GS. Their solution was to use a tube, which pretty much defeats the advantage of tubeless tires. If you look closely at the bead area of those tires, you'll see mold lines that run radially across the sealing surface. Some riders have had success using a razor blade to clean the flashing off those lines to get a good seal. I've had no issues, but then again, I use a soft wire brush and solvent to clean the bead areas of the rim every time a fresh tire goes on. And I use a tire machine designed for motorcycle tires that doesn't screw up the sealing surface.

If it turns out there is corrosion, you might give Woody's Wheel Works in Denver a call and see if they have a solution. They're the only shop I know that can true or replace a tubeless BMW rim, and if anybody has an answer, they will.

8166 Scot Marburger, This email address is being protected from spambots. You need JavaScript enabled to view it.
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2 weeks 6 days ago - 2 weeks 4 days ago #5895 by Wobbly
Replied by Wobbly on topic '89 GS: Air Leaks Around Front Spoked Wheel
Scot -
I know that I'm a bit OCD and eccentric about motorcycle care, and that everything I say/do is 'over the top'. But as the 'average man on the street', would you tell us how often you check your GS tire pressures, please.

Thanks.

Don't hide 'em, Ride 'em !!
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Last edit: 2 weeks 4 days ago by Wobbly.

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2 weeks 6 days ago - 2 weeks 4 days ago #5896 by jarthur
Replied by jarthur on topic '89 GS: Air Leaks Around Front Spoked Wheel
I check air pressure every time I ride this bike which I confess is not very often. My regular ride is a R1200GSLC.

If the air compressor is on for my other bikes they all get refreshed at the same time even if not going to be ridden.

I only have ridden dry pavement since these tires were installed.

I asked the dealer to take pictures of the rim before the tube and tire was installed. I got photos of the tire instead and they are attached. What is shown doesn't mean much to me as I do not know what was done when the tires were mounted originally.

I do not have a tire machine and, having done dirt bike tires by hand before and imposed minor damage to the rims, I am reluctant to start on this myself by hand.

Being new to the airhead community I value and appreciate the feedback.

Best,

Jack
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