Tube size?

I'm planning on new dunlop 606 tires. Would like to use heavy duty or ultra heavy duty tubes. (bridgestone)
Which size tubes will work best with the 90/90x21 and 120/90 tires?

Tube size doesn't matter as much as you would think, (tho maybe better riders would disagree?).
Whatever 21 you can find will fit just fine for the front. I'm assuming the other is your rear at 18....so any 18 will fit.

Tube size is important to avoid creasing\folding and the possiblity of tube puncture from chaffing in these cases. See if this helps (I have not checked for accuracy).
http://www.cb450stuff.com/tires/

cmtnwr wrote:

I'm planning on new dunlop 606 tires. Would like to use heavy duty or ultra heavy duty tubes. (bridgestone)
Which size tubes will work best with the 90/90x21 and 120/90 tires?

Anyone happen to have the stock front and rear tubes handy to say what size they are?

Just curious - the tube size is not mentioned in any of the Yamaha service/repair manuals I have. Tire size, rim size... tubes not mentioned.

your better off going on the small side, stops folding/pinching and easier to install especially with ultra heavy duty's. to suit those i'd use 80/100-21 in med and ultra heavy and 110/100-18 in med and ultra.

Jäger wrote:

Anyone happen to have the stock front and rear tubes handy to say what size they are?

Just curious - the tube size is not mentioned in any of the Yamaha service/repair manuals I have. Tire size, rim size... tubes not mentioned.

I buy my tubes based on the tire size. On the tube's box it's written what size of tire it fits. A tube has a fixed diameter and a variable width and height size.

When I go camping I don't carry two spare tubes. I just carry one of the larger diameter, say 21", and a set of patches. The 21" is not the best for the 18" but it does the job and in an emergency you can use it on a smaller diameter wheel unlike a smaller one that doesn't fit on a larger one.

The reason I asked if anyone had the stock size tubes to grab sizes off is I tend to go with the default that Yamaha knows best unless I have additional information. Looking at assorted charts, I see information that suggests that 3.50/4.00, 3.75/4.00 and 4.00/4.50 will work for the rear, and 2.50/2.75 and 2.75/3.00 for the front.

I suspect that the tubes Yamaha installs at the factory are in one of these sizes, front and rear, and unless I have a good reason to do otherwise, I tend to stick with the sizes Yamaha thought were right for the bike.

Jäger wrote:

The reason I asked if anyone had the stock size tubes to grab sizes off is I tend to go with the default that Yamaha knows best unless I have additional information. Looking at assorted charts, I see information that suggests that 3.50/4.00, 3.75/4.00 and 4.00/4.50 will work for the rear, and 2.50/2.75 and 2.75/3.00 for the front.

I suspect that the tubes Yamaha installs at the factory are in one of these sizes, front and rear, and unless I have a good reason to do otherwise, I tend to stick with the sizes Yamaha thought were right for the bike.

As best as I recall when I pulled the original tubes they were not marked at all. I had a rear flat--about 4 miles from the house--rode it home on the flat. The rear tube had split along the seam so I pulled both and replaced the tires as well. I recall-- well at my age that can be iffy --that there was no size on either tube. I'll look and see if I have the OEM front tube on my shelf but I think I canned it.

From my 2009 WR250R Parts Catalog:

Front:
94108-21019-00 Tire (80/100-21 M/C 51P)
94209-21229-00 Tube (80/100-21 M/C TR4)

Rear:
94112-18028-00 Tire (120/80-18 M/C 26P)
94212-18230-00 Tube (120/80-18 M/C TR4)