inner tubes

[Missouri Bob]

Back in the 70s and 80s, I replaced more than a few tires that had inner tubes. I even managed to repair/replace several tubes on the side of the road using my BMW's tool kit.

 

That was then. This is now.

 

Today, when I attempted to replace a tire and tube on a 1975 Honda, I managed to puncture two new tubes before I gave up. Although I am no longer willing to ride on a patched tube, I may patch them just so I can practice tire mounting.

 

When the replacement tubes arrive, I'll have a local shop do the work. This has cured me of wanting a dirt bike.

 

Bob

[johnlt]

I use the "super heavy duty" tubes on my dirt bikes and they are much less likely to get "pinched" during the mounting process. A lot of tire lubricant also helps.

[upflying]

Inflating the tubes slightly helps prevent pinching them.

[CoarsegoldKid]

Tubes are only a pain in the ass because you should or at least I do, carry a front and rear spare plus an assortment of tools, patches and mounting lube.

I'm new to the dirt scene. Three months new. I fretted over tire changing the old tires for the new D606 knobbies. I poured over You Tube vids to watch how it's done and get tips.

The first tip is use long spoons. I bought some from Cycle Gear but decided to get 2 light weight Motion Pro spoons with the proper hex closed end wrench on the other side to fit the axle bolts. While I was at it I bought the bead buddy and a valve guiding tool.

Since changing tubes or patching could actually happen out in the woods far from civilization I decided to change my first tube under a tree in the dirt in the back yard. I don't have grass. So with the towel I'm going to carry with me at all times I began the task. I think the most difficult part of the entire process is removing the wheel from the bike. And even that isn't difficult.

Remove valve core. Put sprocket side down. Step on side of tire to break the bead all around. Continue on breaking the bead on the other side. Loosen the rim lock(s) almost to the last thread. Insert bead buddy and 1st spoon about 2-3 inches apart from the bead buddy pry the bead up, then second spoon pry the bead up. Remove 1st spoon to a position 2-3 inches from the 2nd spoon. And so on all the way around. It took me about 30 seconds to do first side. Repeat the task on the other side. Now the wheel is sitting inside the tire. Set assembly upright. Grab the tire with one hand and wheel with the other. Rotate the wheel up and out of the tire.

To mount:

Baby powder the tube and innerards of the tire. Lube the inner bead edge you plan on mounting first paying attention to rotation arrows. Lube can be anything. KY, Prep-H, tire lube of your choice. Wheel sprocket side down. Press on the tire. Now stuff in the tube and inflate a bit so as to remove wrinkles. This can be done sometimes before you feed in the tube. I tried it but had to remove some air then had to replenish some before mounting the second bead. This process prevents pinching. Feed the valve guide through the hole. The rubber band tube protector my shift so lube it at the hole. Pull the valve through and place the nut on it so it doesn't fall in the wheel. Now lube the second inner side of the bead area. Repeat the reverse experience learned from removing the tire. Sliding the spoons grabbing little bites of bead at a time. Keep going. Almost done. Give attention to the rim lock. Fill with air. Done. It took me about 10-15 minutes to mount my first tire. Much faster than my first BMW tubeless tire mounting.

[Guest Kakugo]

Don't know if they are available in the US but dirt riders around here have taken using Michelin Bibi-Mousse en masse: Michelin site (in French)

It gives the same feel as a tube at 1/0.9 bar pressure and was originally developed for the Dakar Rally.

Pretty impressive stuff, only downside is you have to replace it every six months, regardless of how often you ride the bike.

[eddd]

I'm with Joe in that I practice before I need to do it off road somewhere. I do get lots of practice with my mountain bike, but the dual sport is obviously a different situation.

 

I think your idea of patching and practicing is a good one. Go slow, use the correct tools, which would be spoons, go slow, stop and check before sticking a spoon in there, and did I mention take your time?

 

Inflating the tube just enough so that it fits in the tire is the way to go.

 

You will become skilled at this and get to where it doesn't take as much time.

[lkchris]

Baby powder the tube and innerards of the tire.

 

For sure.

 

And in case you'd like to avoid the "cute" smell of baby powder, you can get actual tire mounting talc at a bicycle shop.

 

Some posts are more awesome than others, I admit.

[Missouri Bob]

I'm pretty much on board with the process. The term "spoons" gets my attention. Would they differ from the WMD that I use?

 

Bob

 

[CoarsegoldKid]

My spoons are broader I think. Windex might not be slippery enough.

[CoarsegoldKid]

Don't know if they are available in the US but dirt riders around here have taken using Michelin Bibi-Mousse en masse:

These Bibi-Mousse are not recommended for street riding of any distance. Sometimes I need to ride 30 or 50 miles at highway speed to get to the dirty parts.

[Missouri Bob]

Allow me to hijack my own thread.

 

Metric tire sizes. Since one inch equals 25.4 mm, I would think that what was once labeled 4.00-18 would now be 100-18. Of course there is the aspect ratio. The old tires were pretty tall, so I would expect an aspect ratio of 100. That line of thinking leads me to translate 4.00-18 as 100/100-18.

 

The front tire at 3.25-19 would translate to something like 80/100-19.

 

Of course, it seems that those sizes don't exist. What sizes would you suggest as replacements for 4.00-18 and 3.25-19?

 

Thanks.

 

Bob

[johnlt]

Here is a conversion chart: link

 

[Antimatter]

I can't add much, other than to say I use furniture polish for tire lube, and I carry a can around with me to clean my helmet visor also.

 

So far I haven't had any pinch flats (knock wood), but I have had problems with rim strips moving around and causing problems.

[outpost22]

The one thing I have lots of experience with is tubes. We used to have to change tubes in 5-10 minutes during ISDE qualifiers. There is no great mystery to working with them. I would advise (however redundant this may be to the other posts) the following:

 

Since I'll assume you aren't in the middle of an ISDE qualifier and you're not dropping "minute"s doing this:

 

1) Always make sure you clean and debur any imperfections on the inside of your rim prior to mounting any tube/tire. Check for protruding spoke nipples, etc.

2) Pre-inflate your tube and make sure it doesn't leak. You'd be surprised about this one.

3) While it's inflated, rub baby powder all over the tube.

4) deflate the tube

5) Place tube in tire and inflate slightly to a "round" shape.

6) Align rim valve stem hole near the valve stem.

7) Feed stem through hole partially and add lock nut to it to keep it from popping back out of the rim hole.

8) push rim through the tire (mostly) being careful NOT to rip the valve stem.

9) You can usually lie the tire on the ground and step on the tire/rim to push the last bit of tire into position (provided you don't have a mojolever to use instead). Or, gently spoon the last bit of bead on with a tire lever.

10) Make sure the valve stem is aligned vertically in the rim hole.

11) Use 3 tire levers to install the tire. in place. Make sure they are NOT sharp edged or pointy. Screwdrivers are NOT allowed! Coat the tire bead with RUGLYDE or similar lubricant.

12)Work from a point near the valve stem and spoon the tire bead on, holding the opposite side in place with the 3rd tire lever.

13) At this point I usually take some large "C" clamps and small strips of wood and compress the tire bead into the center of the rim on the opposite side of the tire I'm trying to work the bead on. This will give you lots of extra give in a stiff tire carcass, making that last 2-4" of bead go on smoothly.

14) the MAIN thing to watch for is most guys insert the tire lever too far into the rim/tube area, pinching the tubes in the process. I barely put enough lever into the rim to do the job. The bead should go on without too much hassle.

15) inflate the tube/tire and pop the bead out and finish/balance/whatever and you're done.

16) A tire machine helps a lot. We didn't have that luxury in Baja where we fixed 9 flats with tubes. It wasn't the place to "learn by doing". Trust me

[Missouri Bob]

Success.

 

The two things that seem to help the most were 1) starting with a mostly-inflated tube inside of the tire and 2) a lot of lubricant.

 

Thanks.

 

Bob

[lkchris]

Here is a conversion chart: link

 

There's no such thing as a "conversion chart," as the tires are NOT equivalent ... just close.

 

You'd be surprised, for example, as an Airhead owner to learn how many brands offer 4.00X18 and 3.25X19 in Germany but don't offer them in the USA. Even same model tire. Manufacturer spec legally required in Germany, not in USA.

 

For my R80G/S I imported from Europe Conti TKC-80 in 3.00X21 and 4.00X18 since not sold in USA (at least back then). Isn't it simply obvious that the tires aren't the same if the manufacturer makes both?

 

What sizes would you suggest as replacements for 4.00-18 and 3.25-19?

 

There are none. Buy tires from manufacturers that support Airheads and not from those that think close enough is good enough.