1. mroddis

    mroddis Been here awhile

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    Hi everyone,
    I'm a noob still and wondering if I've made my first online purchase error....

    I ordered a rear tube to compliment the spare front one I was given by the original owner. I received it today, and noticed that it is big.....and heavy. I ordered a Michelin Heavy Duty tube - 4mm (as it was the only one I could see online) as I figured a heavy duty one was a good choice.(bigger is better, right?)

    Now my existing front tube box is no bigger than approx 4 oil filter boxes (it's all i have lying around that I figure you guys could visualize). The new one (rear, 18" and therefore 'smaller') is in a box at least double that of the front one. And it seems to weigh at least double...

    So my question is - did I overdo it? I want to carry these tubes with me, but I don't think I can haul around such a big tube. What do you guys use? What size/thickness should I have bought?

    Details:
    2006 950 Adventure
    Running Conti Attacks currently, also have a set of Mefo/Heidenaus
    80/20 street/dirt rider
    200 lbs rider.

    Thanks all,
    Matthew
    #1
  2. DirtyADV

    DirtyADV Long timer

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    Usually just go with heavy duty tubes in the tires and as a spare carry a 21" thin tube and patches.

    Should the rear tube be ripped beyond repair a 21" should be possible to get in there and take it easy until it can be replaced with a correct size tube.

    /Johan
    #2
  3. FakeName

    FakeName Wile E Coyote SuperGenius

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    That's the tube (the 4mm) I use, but carry 1 or 2 standard duty spare 18" tubes, depending on terrain and how far I'm away from civilization.

    In my opinion, you did not make a mistake.

    About that 21" spare- I've carried a 21 spare exclusively for years on my EXC. Then, a few weeks ago, I got a flat on the rear of the 990 and had to face the facts- a 4.25" rear 18" tire is a BIG space to fill with a 21" front tube. I got away with it- ran the 21 for over 100 miles, but will be carrying a 18 in the future.
    #3
  4. jon6.0

    jon6.0 Been here awhile

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    I run the Michelin heavy duty tubes in the bike and carry thin standard duty tubes as spares. Usually just a 21" tube, but if I'm going way out in the middle of nowhere I will also carry an 18" standard duty tube as well. When I'm offroad, I only air down to 30psi to prevent a front pinch flat and to prevent bending the wheels.
    #4
  5. catalina38

    catalina38 Long timer

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    Put the new tube in the tire and keep the old thin one as a spare.
    #5
  6. dwj - Donnie

    dwj - Donnie Long timer

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    I worked in manufacturing facilities for tubes for over 26 years of my career in the rubber industry. I often read of people carrying a 21" tube as a spare for both front and back. These people often say the 21"tube will be good in the rear for 100 miles or so. While my highest position was General Manger of the total operation, I am not presenting myself as a technical expert. I came up through the production ranks. Anyway, when I carry a single tube as a spare, I carry something like a 4.50-18 or a 4.00-19. In my opinion, this is a much better compromise than using a 21 for a 17 or 18 inch tire. The main concern from a technical stand point is the amount of stretch put on the walls of the tube to fill the tire cavity. The 18 or 19 spread over a 21" wheel will introduce less stretch or thinning out than the 3.00 cross section of the 21" tube filling out the cross section of most 17 or 18 inch tires. If the tube is stretched too much filling the cavity of the tire, it will have thin spots that will tend to lose air pressure at a faster rate than normal. Have you ever had a tube that kept losing air faster than normal, but you could not find a hole? It might not have had a hole, it may have simply had one or more thin spots that were allowing air to pass at a greater rate than normal. This is a very simple explanation of a complex subject. BUT, AGAIN, I AM ONLY SHARING MY OPINION! :deal
    #6
  7. Afry

    Afry Why hike?

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    dwj - Donnie - Good food for thought, I may switch to a 4.00/19 as a spare when riding locally.
    #7
  8. jon6.0

    jon6.0 Been here awhile

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    So you are saying use a 4.0-19 in the front for a 21" wheel also?
    #8
  9. mdfehrmann

    mdfehrmann Been here awhile

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    I run and carry standard duty tubes on my 950adv, 1 flat in 50,000 miles...I better knock on wood...

    Matthew
    #9
  10. dwj - Donnie

    dwj - Donnie Long timer

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    In my unqualified opinion, yes! :D And if I put one on my 21" wheel in the outback, I would not change it till I changed the tire. But that is just me! For me, the spare tube should be 1 or 2 inches larger than the rear tire. If you put a 19" tube in a 17" tire, make sure that you fit it evenly around the rim to minimize folds. You may notice a slight fold when you remove the tube, but that should not be a problem. I would not do this if I was attempting a land speed record! :rofl You will also have to be really careful to make sure that you do not fold the fatter tube when you put it into the skinny from tire. :deal

    Also, I would not run the extremely thick HD tubes unless I was running really low pressure off road where pinches are the greater reason for flats. I see no reason to run thicker heavier tubes on a road bike. The thicker tube will generate higher temps, leading to faster tire wear, not to mention increasing unsprung weight. I have ridden all but the last few hundred miles of the Trans America Trail, a fair amount of off road in the Smokey Mountains, plus some really aggressive stuff in Mexico and Nicaragua on my recently sold KLR. I never used nothing but the standard weight tubes, but I very rarely ran less than 18 pounds of air pressure. I never use a patched tube, except in cases of emergency! :deal Unless you have access to a heated press, the patch is going to come off, it is just a matter of when! :deal And even if it is "cooked" on, I would still change it at the first opportunity.
    #10
  11. DeepInIt

    DeepInIt Long timer

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    The simple solution is buy an SE. The thinner rim produces a lot less stretch on a 21" replacement tube :D
    #11
  12. FakeName

    FakeName Wile E Coyote SuperGenius

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    Thanks for your observation- much appreciated.
    #12
  13. Pops of the desert

    Pops of the desert Adventurer

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    I have a rear tube in the right fairing and a front tube in the left. The front will fit with the canister in place. Both are standard duty as HD will not fit.
    #13
  14. FakeName

    FakeName Wile E Coyote SuperGenius

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    When you do that, do you have to remove the fairing to get to it? Or is there an easier way?

    Thanks.
    #14
  15. Pops of the desert

    Pops of the desert Adventurer

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    Yes you need to pull the rear of the fairing out to remove the tube. Takes about 5 minutes.
    #15
  16. Afry

    Afry Why hike?

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    Just a note about twisted tubes - Bought my SE used and ran 3k miles on the rear tire (908) when I changed it out I found the tube (standard) was twisted over one complete turn inside the tire from a bad install(!).

    There were two sections of the tube squeezed down where it was folded over that obviously had very little air in those sections of the tube.

    Not knowing this I ran dirt down to Mikes in Baja and did another trip to Carrizo Plain and then high speed slabbed it home for 5 hours on Hwy 5 on this setup with no issues.

    A little fold in a wrong sized tube is probably not an issue.
    #16
  17. jon6.0

    jon6.0 Been here awhile

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    My buddy actually folds a 21" tube over on itself when he uses one for a rear 18 or 19. Works fine until you can replace it with a proper size tube.
    #17
  18. FakeName

    FakeName Wile E Coyote SuperGenius

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    And does he do so with a 150 size tire and 4.25 rim?

    Here's the deal- we've all done it- use a 21 in a 18. But mostly on dirt bikes to get back to the truck, and with tire/wheel combinations that are pretty similar.

    But on ADV bikes,there is no truck. The garage out of which we rode several days ago is a few thousand miles away. I don't want to break down the wheel/tire for a flat repair and put something in the tire that won't last until I get back to the garage.
    #18
  19. Sumi

    Sumi Long timer

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    Well if you're not out alone in the middle of the Sahara desert - which I doubt, then I'm sure there will be a place to buy a correct size tube in let's say a max of a 1000 mile radius, probably half or less. IMO ADV riding is not about worrying about what might happen, or what is going to fail.. It's about enjoying the ride, and if something goes bad, then you improvise and solve the situation the best as you can.

    Carrying a 21" and a 18" tube is way overshooting imo. Carrying a 21" tube.. well OK, but probably patches would be enough. I know of a guy (not the starbucks poser kind), who was filling (stuffing) the tire with grass, until he got to a place were he could buy a new tube. Ok, this probably won't work in the desert:)). Don't want to offend anybody, just sayin' how things work out when in a need..

    Also for the OP, I don't get it why would anybody use a HD tube in Conti Attacks, or K60's (if that's what we are talking about).. Especially if 80% of the riding is on the road.
    #19
  20. soggysandwich

    soggysandwich Banned

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    Thank you very much for your post...I learned something today,,,always a good thing !
    Your life experiences are MUCH MORE valuable than 99% of the keyboard jockeys on here..
    I never did "get" the carrying of a 21" tube for filling the space in a fat 18" rear tire...... would take ALOT of extra air to keep the tire properly inflated
    #20