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Discussion Starter #1 (Edited)
Rear inner tube size?

I'm sorry to start new thread with such a small question, but I've read many discussions about tyre sizes and brands, but didn't find anything about tube sizes.
My problem is that local tyre shop has a choice of tubes, but they aren't bikers and I must say which size I want to buy!
Bike is Adventurer 1999, rear tyre 150/80-16.
Thanks
 

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I also had some trouble finding the correct size tube for my '96 Adventurer (160/80-16), but I finally found a correctly sized Metzler tube that has a 90 degree valve stem. It is listed as a 15"-16", Type "B" tube.
I purchased it from www.motorcycle-superstore.com, SKU - 100775, $16.99 US
 

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Discussion Starter #3
I'm not sure I will have a big choice- like 90 degree valve stem (what I would like for reall). What they said me on the phone they have for R16:
2.5X2.75
2.75X3.0
3.25X3.5
4.00X4.25
5.00X5.25
These are with of the rim as I understand, but I don't know which one suits my rim...:confused:?
 

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I'm not sure I will have a big choice- like 90 degree valve stem (what I would like for reall). What they said me on the phone they have for R16:
2.5X2.75
2.75X3.0
3.25X3.5
4.00X4.25
5.00X5.25
These are with of the rim as I understand, but I don't know which one suits my rim...:confused:?
This caught me out a while back when I bought a new rear tube, I thought they were sized by the rim size, they are not. The rim is 3.5"

You need to order a tube that is the same size as the tyre, that is 150mm or 160mm x 16. That would equate to 6.00 inches.
 

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I found This explanation

ok...

let me explain tire sizing
example: your new rear tire is a 150/60-17
the first number is the tread width in mm. so the tires tread is 150mm or 15cm wide. the 2nd number is the percentage of the tread width that equals the sidewall height of the tire. this is called the aspect ratrio. so 60 percent of 150mm is 90mm so the tire sidewall is 90mm tall. the last number is obviously the rim size.
here is a website to explain it some more or for some conversions between the metric system (the one i just explained) and the american/standard system:
http://www.webbikeworld.com/Motorcycle-tires/tire-data.htm
it also shows speed and load ratings

tubes are sized the same way as the tires are. lets take the rear for example:

140a160/70b-r17m/c

the 140a means nothing as far as we are concerned. its probably a manufacturers code that specifys whether its a regular or heavy duty tube or something like that. i dont know what the b after the 70 means but just ignore it, and the m/c at the end means its a MotorCycle tube.

properly inflated the tube will fit a 160/70-17 size tire. meaning a tire that is 160mm wide and 112mm tall on a 17 inch rim. heres where your confusion came in: tubes can stretch and form a little so getting a tube that is a little off is ok to a point. are the tubes you got the exact right ones? no but they should work fine.

your tire is 150mm wide whereas the tube is designed to inflate to 160mm. 10-15mm difference between tire and tube is fine.
your tire is 90mm tall and the tube is designed to inflte to 112mm wide, still within the 15mm boundry. the only specifacation that has to be exact is the rim size. in a pinch out on the trail you can use a larger rim size tube on a smaller wheel temporarily to get you home. for example a 100/80-21 onto a 110/100-18. but that has little to do with an SM i was just telling you as an example. but you cannoth stretch a 18" tube onto a 21" inch rim. it would destroy the tube if you ever got in on there.

sometime you may not find the exact right size tube, some arnt even made. for example: the drz400S has a 100/80-21 size front tire. i ahve only foud one btrand of tube that make trhat size. every other front tube in that range is a 90/90-21. so i could run a 100/80-21 if i wanted too unless i tracked down that specific brand of tube. besides that a 90/90 is so close it works great.

so to sum it all up, get the closest match to your tires you can find, if they are a little off that is no problem as long as you dont get to far off. like i said 10-15mm range is what i like to stay in. also, if you have a choice between 2 tubes where one is slightly larger and one is slightly smaller, always go for the larger one. it is better to stretch a tube a little or not at all then to strecth a tube more than nessacary.

i would keep the aspect ratio (2nd number) a little tighter. in other words i wouldnt vary more that 10% in either direction. because the final product is a funtion of the first number and the errors are doubled. make sense?

final example of possible range of tubes that will work for your new rear:
tire is a 150/60-17
anything between 130 and 170 should be ok for the first number (tread width)
anything between 50 and 70 should be ok for the 2nd number (aspect ratio)
and it must be a 17" (unless you are stuck miles from home and can only get an 18" for example
 

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Discussion Starter #6
Thanks a lot, Gdsila:)

This gives the whole picture of what is what and now I can take my own decision.
 

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Discussion Starter #7
went to the shop today- choice was limited, when asked about 90 degree valve stem- guy at the desk just rolled his eyes:rolleyes:

got 5.00/5.10 R16- on the tight side but within limits that Gdsila descibed. Hope this will work fine.
 
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