General Tube Tire Tech Tip

[Kedo Parts USA]

I see a lot of tire question and tips, before I started KEDO Parts USA I restored some bikes and I was a tech for a handful of years. One day I was test riding a bike I just got done restoring, maybe it was the slow process but in the end it was my negligence to double check everything. After making sure everything was okay, I wanted to see what the bike would do. I opened it upand about as soon as I did this the back tire went completely flat and I did a controlled stop into a ditch. The culprit tube due to the valve core not being tight. The tire is the first contact patch for motorcycles and should always be double checked. Learn from my mistakes always double check your valve stem nut after instillation, and even after a professional does it. I keep the valve stem on my tool box to remind me of how much I could have lost because of one nut.

 

 

Edited May 21, 2022 by Kedo Parts USA

[thepointchris]

Thanks for adding the tip @Kedo Parts USA

Here's a question for all: I fitted Dunlop Missions about 2000M ago, and at the same time replaced the tubes, thinking I keep the OEMs as spare. The replacements were "generic" from one of the big Cycle Stores. I'm losing pressure weekly, between rides, to the tune of 3-5 psi at a time. Starting at 32/36 on a Sunday, I'd be 27/33 a week later. As an experiment I added a sealant, thinking the tubes are poor quality/porous, but at this stage I have not sorted the issue. I'll me doing the same this week to come, paying attention to cold temps etc, but I'm at a loss to explain whats wrong?

 

1) Valve Cores screwed in tight, and not leaking

2) If I pinched the tubes (both!) when installing, I should be losing air faster?

 

I look forward to some collective wisdom here, please!

Chris

[BikeBrother]

1 hour ago, Kedo Parts USA said:

I see a lot of tire question and tips, before I started KEDO Parts USA I restored some bikes and I was a tech for a handful of years. One day I was test riding a bike I just got done restoring, maybe it was the slow process but in the end it was my negligence to double check everything. After making sure everything was okay, I wanted to see what the bike would do. I opened it upand about as soon as I did this the back tire went completely flat and I did a controlled stop into a ditch. The culprit tube due to the valve core not being tight. The tire is the first contact patch for motorcycles and should always be double checked. Learn from my mistakes always double check your valve stem nut after instillation, and even after a professional does it. I keep the valve stem on my tool box to remind me of how much I could have lost because of one nut.

 

 

Hi, what do you mean? That you screw the nut onto the rim?

I learned from my offroad buddies, if you put less pressure in the tube with offroad riding, the tube can move inside the tyre, due to braking/accelerating. And it can rip off the stem. So they move the nut up, so the stem can move a bit, so less chance to be ripped of. I do that since then. Even at road pressures. See picture.

[Kedo Parts USA]

51 minutes ago, thepointchris said:

Thanks for adding the tip @Kedo Parts USA

Here's a question for all: I fitted Dunlop Missions about 2000M ago, and at the same time replaced the tubes, thinking I keep the OEMs as spare. The replacements were "generic" from one of the big Cycle Stores. I'm losing pressure weekly, between rides, to the tune of 3-5 psi at a time. Starting at 32/36 on a Sunday, I'd be 27/33 a week later. As an experiment I added a sealant, thinking the tubes are poor quality/porous, but at this stage I have not sorted the issue. I'll me doing the same this week to come, paying attention to cold temps etc, but I'm at a loss to explain whats wrong?

 

1) Valve Cores screwed in tight, and not leaking

2) If I pinched the tubes (both!) when installing, I should be losing air faster?

 

I look forward to some collective wisdom here, please!

Chris

Based off my cycling a moto experience there could be a lot different issues. the seam on the tube coming un-done. Porous in the tube itself. 

What kind of sealant did you use? Tubeless sealant or slime? 

[Kedo Parts USA]

36 minutes ago, BikeBrother said:

Hi, what do you mean? That you screw the nut onto the rim?

I learned from my offroad buddies, if you put less pressure in the tube with offroad riding, the tube can move inside the tyre, due to braking/accelerating. And it can rip off the stem. So they move the nut up, so the stem can move a bit, so less chance to be ripped of. I do that since then. Even at road pressures. See picture.

That's exactly what I did. In the same scenario, I gassed it, spun the tire on the rim enough to pull the nut to the rim and ripped the tube from the valve. 

[thepointchris]

46 minutes ago, Kedo Parts USA said:

Based off my cycling a moto experience there could be a lot different issues. the seam on the tube coming un-done. Porous in the tube itself. 

What kind of sealant did you use? Tubeless sealant or slime? 

Cycling and tubeless experience here too.

I used a tube specific sealant, and that really was just to try something. 

I've discounted seams and pinches- not likely in both the tubes, and I would lose air faster.  

I deduced poor quality, porous tubes,  but the the sealant, any sealant, would take care of the porosity?

I'm giving it another week of closely monitoring. 

[Kedo Parts USA]

It could also just be bad luck, on vintage bikes I have narrowed things down to spark plugs. Changed the spark plugs and nothing. It didn't make since then I changed them from a different store/batch and they worked. 

 

I know that the Panaracer sealant isn't the best and wont work under 32f. I am a big fan of orange seal, it has never left me stranded hours away from home. 

[witgen]

2 hours ago, Kedo Parts USA said:

That's exactly what I did. In the same scenario, I gassed it, spun the tire on the rim enough to pull the nut to the rim and ripped the tube from the valve. 

I've ripped off two stems. Both times from UHD front tube.  On first occasion I think it was my too generous application of lubricant when changing a tyre (no more soap water for me unless I have rim locks). Second time the rim was so badly dented that the tyre would not seat properly. Both of those times the bolt was tightly secured all the way.  

 

If the tyre is going to spin on a rim, that nut won't stop it unfortunately.  Like @BikeBrother,  I don't tighten the bolt anymore. Or to be more exact I have bunch of those in my junk box because I don't even bother to put it on. In addition that there is some leeway, you can also easily check if there's been some movement. If the stem isn't pointing up, tyre has spun a bit on a rim and you notice it. 

[jdub53]

5 hours ago, thepointchris said:

Thanks for adding the tip @Kedo Parts USA

Here's a question for all: I fitted Dunlop Missions about 2000M ago, and at the same time replaced the tubes, thinking I keep the OEMs as spare. The replacements were "generic" from one of the big Cycle Stores. I'm losing pressure weekly, between rides, to the tune of 3-5 psi at a time. Starting at 32/36 on a Sunday, I'd be 27/33 a week later. As an experiment I added a sealant, thinking the tubes are poor quality/porous, but at this stage I have not sorted the issue. I'll me doing the same this week to come, paying attention to cold temps etc, but I'm at a loss to explain whats wrong?

 

1) Valve Cores screwed in tight, and not leaking

2) If I pinched the tubes (both!) when installing, I should be losing air faster?

 

I look forward to some collective wisdom here, please!

Chris

 

In my experience, natural rubber tubes can lose a couple psi per week while others (butyl?) hold air much better. Trade-off is that glue and patches hold fast to natural rubber tubes better, which can sometimes be an issue on synthetic rubber tubes.

 

If you've installed natural rubber tubes, could be that sealant just doesn't have the ability to act as an internal skin to 100% seal the entire surface. Just a thought...

[Stevoh]

I've just replaced front and rear tyres I have a Motoz uhd in the rear and a standard heavy duty Michelin I think tube in the front, so I'm up for a wheel balance of course, the rear should be ok but the front I have applied slime to combat pinch flats, it's very rocky round these parts, probably impossible to balance with the slime in place so I was considering a new tube, 4mm? 3mm?  Standard? Butyl? Natural rubber? I thought 4mm for sure until I read this attached article, happy to hear your thoughts.

Should I use heavy duty tubes? – Texas Adventure

 

[Kedo Parts USA]

2 hours ago, Stevoh said:

I've just replaced front and rear tyres I have a Motoz uhd in the rear and a standard heavy duty Michelin I think tube in the front, so I'm up for a wheel balance of course, the rear should be ok but the front I have applied slime to combat pinch flats, it's very rocky round these parts, probably impossible to balance with the slime in place so I was considering a new tube, 4mm? 3mm?  Standard? Butyl? Natural rubber? I thought 4mm for sure until I read this attached article, happy to hear your thoughts.

Should I use heavy duty tubes? – Texas Adventure

 

During the Dirty Kanza / Unbound a lot of racers fill their tubes with stans no tubes or orange seal. I would look into that before slime. 

[Cruizin]

My stock tires lose air like crazy. Im airing them up every weekend.

[Kedo Parts USA]

sounds like some issues from Pirelli, after my puncture I replaced them with stock tubes and I have had no issues. Also the bike I purchases was a demo, with no issues with the tubes. 

 

[Kedo Parts USA]

some fun news, it seems as if this is a much more debated issue than I thought. One of the three run it lose, the others tighten it down. I have a few engineer friends that design tires and wheels. I will reach out to them. I also hope to find a scholarly paper on it. 

 

 

 

Edited May 22, 2022 by Kedo Parts USA

[Stevoh]

30 minutes ago, Cruizin said:

My stock tires lose air like crazy. Im airing them up every weekend.

Same here, probably why I put slime in the front, I thought I had pinch, still airs down pretty quick!