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Old 01-21-2015, 02:07 PM   #1
thetubespoke OP
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R100GS front tire air leak

Hi everyone,

I took off the previous tires (and tubes), and installed Tourances without any tubes. The first night the front tire was completely flat, but I am not sure why. Since then, it seems to leak about 2psi per night. This is with it normally at 40-46psi.

The front wheel is powder coated. It sounds like this is a common issue? Do I just need to clean the tire seating area for it to make a better seal? Would a little bit of bike sealant possibly do the trick?

Thank you,
TheTubeSpoke

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Old 01-21-2015, 02:26 PM   #2
tennessee thumper
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Not uncommon on those Akront rims.

Do a search in this forum for Heidieau tires and you'll see that brand has been one of the main offenders.

My theory is cooler temps cause the rim to contract and loose the bead seal. I had this same issue (front and rear) in colder weather, below 50 degrees. Warmer temps, tires would hold air fine.

Others have adopted tricks and work arounds to solve this, I just use a tube. Not the best solution but it works.
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Old 01-21-2015, 02:36 PM   #3
dfc
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Quote:
Originally Posted by thetubespoke View Post
it seems to leak about 2psi per night. This is with it normally at 40-46psi.
I cant imagine running a front at 46 psi.

Have you checked where it is leaking with soapy water?
Did you hear two pops when setting the bead?
If you had tubes before you must have put in a new valve stem?
Easy to check the valve itself with a dab 'o spit
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Old 01-21-2015, 10:52 PM   #4
Wirespokes
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Quote:
Originally Posted by dfc View Post
I cant imagine running a front at 46 psi.

Have you checked where it is leaking with soapy water?
Did you hear two pops when setting the bead?
If you had tubes before you must have put in a new valve stem?
Easy to check the valve itself with a dab 'o spit
Same here! That's extremely high pressure for a front tire.

Definitely do some research and figure out where it's leaking. Till then it's all guessing and conjecture.
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Old 01-22-2015, 07:58 AM   #5
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did you clean the rim well before re-install?

Yeah, often its the valve itself, with crud in it or a lousy oring
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Old 01-22-2015, 08:57 AM   #6
Mobiker
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I had a Mezteler laser 33 that leaked all around the bead (stuck it in the bathtub - there are advantages to being a bachelor). Many other tires, including an earlier ME33, never had this problem. So.....it could just be that particular tire.
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Old 01-22-2015, 09:01 AM   #7
Biebs
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Have you ridden on this new tire??

How many miles have you ridden on this new tire?? put some miles on it and see if it seals. NEW tire so ride easy.
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Old 01-22-2015, 09:14 AM   #8
thetubespoke OP
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Thanks for the replies.

I never did clean the rim. I'll do the spit test on the valve and maybe later check with soap on the wheel.

I was just really concerned with the front tire being flat the first night and fine the rest. May have just been some kind of fluke.

The bead did seat, it looks fine on both sides. I did put in a sideways valve which I do not like.

I like the theory on hot/cold expansion of the rim. It makes sense to me, especially as it seems like I may see the same thing with the colder weather here.

Regarding the high pressure in the front: It's partly because it's leaking, so it gets better before it gets worse. Also, I run all of my motorcycle tires on the high side. I want them to be predictable and break early. They should last longer at higher pressure and be better on the road. In offroad situations I'll probably turn them down a bit. I may also lower the front relative to the rear due to weight bias and traction. I don't know where the weight is on these bikes, but it seems like most of it is on the rear wheel, so slightly lower pressure in the front could help balance out any understeering characteristics.

I know a guy who ran enduros for years and had his tires at 35 psi to prove you could do it. I'm pretty sure he never had any flats and placed very consistently. This is on an XL250 honda, and of course with knobby tires. He also had his Ducati GT-750 race bike ran at 50psi for the track, on several hour endurance races. Of course, that's with tubes on wire wheels with slick tires.
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Old 01-22-2015, 10:24 AM   #9
tennessee thumper
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Not to state the obvious but you'll tell if the bead is leaking around the rim with soapy water. Mine bubbled up like a bath tub full of suds so it was pretty obvious where the leak was coming from. Guess you'd want to test that in cooler weather, which is what I did.

Seems some tires seat on the rim better than others. As mentioned, Heidenau was the worst offender on the front rim. I switched to a TKC 80 because of the leak and I like the tread pattern better. Can't recall now if I have a tube in the front tire or not.

My rear Heidi had the same issue, so stands to reason there is an issue with that brand as it works with the Akront rim.

First time I noticed this was in Big Bend, TX...woke up one morning with a flat front tire after a night of below 40 temps...simply aired it up and it did not go flat for the remainder of the trip (I was in warmer weather the rest of the journey).
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Old 01-22-2015, 12:12 PM   #10
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Coupla things:

on a pain scale of 1-10 (1 least painful, 10 most, etc), how painful was the mounting procedure? Ie, lots of sweat, blood, and profanity, or easy-does-it? If the mounting was physically/mechanically difficult, (ie using huge truck-size levers/spoons etc) it's possible you damaged one of the beads on install. A damaged bead will still seat properly at 1st inflation, but the dinged spot on the bead will always leak, and leak faster at cold temps ( see, I know a guy that did such a thing mounting a Kenda Big-Block rear-- a true bastard of a tire to mount). I've done both tube and tubeless Tourances in past and they are very stout tires to mount. Squirt soap/water or kitchen counter spray around the rim and you'll see in a flash where the leak spot is

Second, you said you mounted an angled valve stem. If it's one like this:



the torque on the mounting nut is VERY light on these, like just a few inch/Lbs. Overdo that and it wrecks the seal-- the valve body will leak where valve passes through rim.

3rd, check that the valve core itself is sound, fully seated etc

Get this squared away. A compromised front is the last place to be less than 100%
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Old 01-22-2015, 05:17 PM   #11
CptImagine
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93 GS, I run Distanzias at 42psi, check the air every several days on the road . They leak down a bit some times, depends on temps . @ 42psi I wear out 2 rear tires to one front .
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Old 01-22-2015, 07:12 PM   #12
akabeton
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Valve stem

You say in the original post that you were previously running tubes. If the bike was originally tubeless and the PO converted to tubes the original valve stem may have been drilled out. That could be your problem right there.

Also 42psi seems very high. I run 32 front and 36 rear on TKC 80 mounted on BEHR rims.
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Old 01-22-2015, 07:19 PM   #13
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anything over 40 seems like a lot.
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Old 01-23-2015, 02:21 AM   #14
gsd4me
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Quote:
Originally Posted by Stagehand View Post
anything over 40 seems like a lot.

Anything much over 30 seems a lot to me.
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Old 01-23-2015, 04:04 AM   #15
CptImagine
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My GS has a PD tank, 3 piece alum cases filled with weeks of spares, tank panniers, tools and camping gear . That with geared up 190 lbs of me and get 18,000 miles on front Distanzias, rears 9,000 plus @ 42psi . When on dirt psi is dropped with type of dirt to 24 psi, sand "which I shy away from" even lower . @ 42 on dirt they're not cool . On the highway 42psi gives me safe high miles . They stick in all weather, wear sorta flat in the centers and are never squirrely

I attended a seminar decades ago by Dunlap, at Daytona . They talked contact area, heat dissipation, design criteria, sidewall flex, etc, etc . I've been running at the sidewall max since, because I run a heavy motorcycle .

I've also noticed I'm a bit more anal about tire pressure, among many riders I know . My "Cycle Pump" gets a lot of use on the road and I use an old screw on angle truck stem . Similar to the one pictured in an earlier post . Slightly over fill and release to 42 at the wheel stem . The rear bleeds down also, far less than the front, but it does .
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