How important is 2 wheel drive

Discussion in 'Hacks' started by CBRider, Nov 29, 2012.

  1. YOUNZ

    YOUNZ Been here awhile

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    I was thinking, for those that don't own a 2 wheel drive/reverse Ural. That's why I mentioned Universality.
    #41
  2. madeouttaglass

    madeouttaglass The AntiHarley

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    Really? I'd be interested to see their Urals. Every one I've ever seen (including my own) has a driveshaft straight off the rear end to the axle stub on the sidecar. I'd like to know where their gear reduction is hidden.
    #42
  3. Sidecar Jockey

    Sidecar Jockey Been here awhile

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    When I said 'no differential' I really meant 'no limited slip'. It obviously has a differential, but both wheels are locked together all the time, therefore one wheel MUST BE SLIPPING (losing traction) ALL THE TIME to avoid driving in a circle or blowing the tranny/differential. This is NOT bad, it just means you need to be on really slippery stuff before engaging the 2wd. For example, it would not use it on 'normal' dirt roads...


    I'll be happy to show you where the reduction is hidden:

    [​IMG]
    The part of the rear differential outlined in red is NOT on the 1 wheel drive differential. This is where the gear reduction occurs, simply by having a different number of teeth on the bevel gear that drives the sidecar wheel than on the bevel gear the drives the bike's rear wheel.

    [​IMG]
    To be more specific, the circled gear is what causes the reduction. The gears pictured above are inside the case circled in the first photo. The circled gear drives off of the pictured ring gear in the Ural's differential, and indexes into the sidecar's drive shaft. It has absolutely NOTHING to do with the gearing of the bike's wheel.

    In theory, you could have a custom one of these made, with more teeth, to make a 1:1 drive ratio of the bike wheel to sidecar wheel, but I have never seen this done. I imagine it is because it would be impossible to turn your rig with both wheels driving and gripping on pavement...

    I'm NOT bashing 2wd. If I had the extra money at the time that I bought my Ural, I would have bought 2wd. I didnt have the extra cash at the time, so I bought 1wd. I'm just saying that I'm very happy with my bike, and do not think that I would NEED to use 2wd if I had it.
    #43
  4. Mr. Cob

    Mr. Cob Howling "Mad", Adventurer

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    Howdy Sidecar Jockey,

    I have no idea what Ural your talking about when you make this statement,

    Quoting from your post.
    The drive ratio of the sidecar wheel is LOWER than that of the rear wheel of the bike, so if the sidecar wheel can't slip you will either drive in a circle or blow out your tranny. I know Ural owners that had the latter happen...
    End of Quote.

    On the late model two wheel drive Ural's, WITHOUT a differential, the pusher wheel and the sidecar wheel, WHEN two wheel drive is engaged DRIVE and ROTATE at the SAME SPEED.


    I think you are confused in this issue, but then again I could be full of $hite but I doubt it.
    #44
  5. Mr. Cob

    Mr. Cob Howling "Mad", Adventurer

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    The gears in the photo you posted are the ring and pinion gear in the final drive unit it itself, the gear you have circled in red is the pinion gear, it is driven by the drive-shaft coming from the transmission. In my opinion you don't have a clue what your talking about but like I said I may be totally full of$hite.
    #45
  6. Mr. Cob

    Mr. Cob Howling "Mad", Adventurer

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    The rig in the photo posted is an old Ural that has the final drive in which there was an OPEN DIFFERENTIAL, there was no gear reduction in it. The biggest problem with this type of drive unit is that if one tire is on a very slippery surface ice for example and the other tire in on a surface that offers better traction, most or all of the power will be delivered to the tire thats sitting on ice and the rig will not move. The open differential drive works very well on surfaces where the same or very close to the same traction is available to BOTH wheels, as soon as one in on a very slippery surface your stuck.
    #46
  7. Sidewise

    Sidewise Been here awhile

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    It's always been my understanding, two wheel drive gets you another 50 yards down the road before you get stuck. I do wish however I'd had reverse on occasions both on the gravel and on the pavement.

    [​IMG]
    #47
  8. Mr. Cob

    Mr. Cob Howling "Mad", Adventurer

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    Howdy Sidewise,

    What MANY people are failing to understand is this, 95-99% of your off road riding may be accomplished in one wheel drive, however sometimes you come to a point on the trail that may be 5 feet long, 50 feet long or longer beyond that bad spot the trail again can be done in one wheel drive. Its getting past that 5 foot section, 50 foot section or longer section that the two wheel drive is used so that you can continue to cover ground. I have very rarely ever been in two wheel drive for more then 50 to 100 feet but with out having the two wheel drive capability thats where the ride would have ended and I would have had to turn around, I prefer to keep going.
    #48
  9. Mr. Cob

    Mr. Cob Howling "Mad", Adventurer

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    Howdy All,

    I think its about time we all get on the same page, heres an old video that gives a simple but detailed explanation of how an OPEN differential works, it even has MOTORCYCLES in it. So kick back for a few minutes and get educated.

    <iframe width="420" height="315" src="http://www.youtube.com/embed/kJY9SxDOTog" frameborder="0" allowfullscreen></iframe>
    #49
  10. SamRus

    SamRus Been here awhile

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    #50
  11. Mr. Cob

    Mr. Cob Howling "Mad", Adventurer

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    Howdy SamRus,

    I carry a "Rope Puller" and will be putting a small winch on my rig in the near future. That said the Rope Puller and or the winch will only be used for recovery purposes where the two wheel drive wasn't enough to make it through.

    I spent decades building and driving very hard core Jeeps in stupid off road situations, I know how to use a winch, with that said I would prefer to shift into four wheel drive with my Jeep or two wheel drive with my Ural then to get out and run a cable unless its absolutely necessary to keep moving.
    #51
  12. Sidecar Jockey

    Sidecar Jockey Been here awhile

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    Mr COB and all else reading,

    I could be mistaken about the gear reduction of the sidecar wheel. If so, I apoligize, I didnt want to mislead anyone. Upon closer look, you are correct, I posted a photo of the wrong gears, i got them from Google.

    I was speaking based on two rigs a friend has. One is a 1970's Ural, the other is a 1970s Dnepr. Both have two wheel drive systems. I beleive he pieced together the system on the Dnepr, I thought the Ural was stock.

    He was telling me that his sidecar wheel is geared lower, to help get some extra 'grunt' when stuck. He even put the bike on a centerstand and jacked up the sidecar to show me. He said the gearing down was acheived by the number of teeth on the pinion gear leading to the sidecar drive shaft.

    His setup might not be stock, hence my confusion about the gearing.
    #52
  13. whitham_wannabe

    whitham_wannabe Long timer

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    I think there is some level of BS, err, confusion in this whole debate, when discussing any sort of off pavement riding.

    To the question of whether it is better to have 2wd or not ... of course it is better.
    To the question of whether it is better to have reverse or not ... of course it is better.

    I think for people to say that 2wd or reverse isn't needed is a little churlish. If there were a 2wd / reverse system out there that cost a couple of hundred bucks, that we could bolt to our bikes in twenty minutes and that didn't mess up our rig's other qualities, we would all have one.

    The problem is that there is really only one viable option for getting these capabilities and the debate of whether people are prepared to 'put up with' the perceived shortcomings of the Russian solution is a subject for an entirely different thread.

    So Claude, when you come up with a $200 2wd and reverse solution for the R100, sign me up!
    #53
  14. Mr. Cob

    Mr. Cob Howling "Mad", Adventurer

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    Howdy Sidecar Jockey,

    Please excuse my gruffness, I am not called Mr. Cob ( Crabby old bastard ) without good reason. Its just that this has been gone over so many times it really gets old after a while.

    I am going to make the "ASSUMPTION" that the Ural your friend has is one that does in fact have a differential that takes up the space that the newer Ural's use to house the NONE differential two wheel drive system. In fact looking at your photo the part of the final drive circled in red is where the differential is on the "Sportsman", and if I am not mistaken your photo shows a "Sportsman" type final drive. On the older Ural's with the differential commonly known as a "Sportsman" they where in two wheel drive all the time but the unit was built on the same principals and worked the SAME as in the short video I posted, there was NOT gear reduction in the unit.

    I am NOT familiar with the Dnepr so I can NOT give any worth while comments on it.

    Give this a try, watch the video again only this time imagine that one of the axles and wheels in the video is the rear tire and wheel of the bike and the other one is the tire and wheel of the sidecar, maybe then it will make sense to you
    #54
  15. windmill

    windmill Long timer

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    It's kinda like after a major snow storm, most vehicles you see in the ditch are AWD, they have a tool they don't know how to use.
    Can't blame the tool for that.
    #55
  16. Mr. Cob

    Mr. Cob Howling "Mad", Adventurer

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    Howdy whitham_wannabe,

    OK now you did, you forced me to look up this word, "churlish" which is a good thing, I try to learn something whenever I can and today I learned a new word, thanks.
    #56
  17. Mr. Cob

    Mr. Cob Howling "Mad", Adventurer

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    #57
  18. Mr. Cob

    Mr. Cob Howling "Mad", Adventurer

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    Howdy All,

    Again, I think many folks who are NOT knowledgeable of the two wheel drive system NOW in use on the Ural's fail to understand its proper use. I am going to post here something that I have posted for YEARS on Russian Iron and Soviet Steeds, as even most folks who own Ural's DON'T really know how to shift into, out of, or how and when to use two wheel drive.

    READ AND PUT THIS INTO USE AT YOUR OWN RISK, IF DONE IMPROPERLY YOU STAND THE CHANCE OF SERIOUS INJURY OR DEATH, NOT TO MENTION BLOWING UP THE DRIVE-TRAIN OF YOUR URAL.



    Long before I bought the after market two wheel drive shifter from Jim at Raceway, I had extended the stock two wheel drive shifter so that it was easy to reach and use while the rig was moving.

    If you look closely at the final drive you will see that even when the rig is in ONE wheel drive the drive shaft going over to the hack wheel turns when the rig is in motion. Inside the final drive there is a "dog clutch" which when moved to the left slides a toothed collar that engages a toothed gear, when these two parts are locked into engagement the rig is in two wheel drive.

    Remember if the following is not done properly you WILL be spending a lot of money replacing parts and depending on where its done and at what speed its done you could get injured or killed. Now that the disclaimers are out of the way this is how its done.

    When shifting in and out of two wheel drive while the rig is moving DO NOT FORCE THE SHIFT.

    To shift into or out of two wheel drive while the rig is in motion, back off the throttle, apply LIGHT pressure to the two wheel drive shifter, when the dog clutch aligns it will slip into engagement or out of engagement as the case may be.

    Because the pusher wheel and the hack wheel may be turning at slightly different speeds, the shift will be made easier if you SLIGHTLY wiggle the handle bars from side to side. Wiggling the handle bars will allow the two tires to come to a common speed where there will be NO STRAIN on the moving parts of the dog clutch this will allow a smooth, easy, quiet and no parts breakage shift.

    Now this is the part that sends shivers up the spines of those who first hear or read this, there is NO NEED TO USE THE CLUTCH. Think about this for a moment, the clutch in no way disconnects power to the sidecar wheel, the shaft is spinning when ever the rig is in motion, using the clutch does nothing as regards the sidecar drive shaft It is the rotation of the hack drive shaft that allows the shift to made while moving.

    MANY times I have come across people who are stopped beating on the two wheel drive shifter with a rock or a hammer trying to get the two wheel drive engaged or disengaged. There is absolutely no need to do this. The reason the final drive can't be shifted into or out of two wheel drive is because the dog clutch is either not aligned or it is engaged in two wheel drive and the parts have strain on them preventing the shift to be made.

    If your rig is at a stand still, transmission in neutral and you want to shift it into or out of two wheel drive all you have to do is roll the rig forward or backward as your rolling the rig have the handle bars turned one way or the other and apply slight pressure on the two wheel drive shifter, as the rig moves in the arc the pusher and the hack wheel will rotate at different speeds, when the different speeds allow the dog clutch to align the shifter will easily move, NO NEED TO BEAT ON IT.

    For the five years I have been driving my Ural's, I have shifted into and out of two wheel drive at speeds up to 60 MPH with out using the clutch and I have NEVER had a problem with the final drive or any other part of the drive train while doing so.

    The trick is to let off the throttle so that your not applying power to the drive train, wiggle the handle bars to align the dog clutch and using LIGHT pressure on the shifter, when this is done right you'll be able to maintain your momentum and get through or over stuff that you wouldn't other wise be able to conquer, shift into two wheel drive before your stuck, shift out as soon as your through the nasty stuff, that way you can keep moving at the optimal speed for the conditions your riding in.

    Now that I have explained how to do this, give it a try and you'll be amazed at how easily, quietly and none harmfully this can be done. If you blow your final drive or kill yourself, don't blame me.

    For those of you who prefer a video, try this, I made this a few days ago.

    <p><a href="http://www.xtranormal.com/watch/13966226/mr-cob-meets-niel-armstrong-on-the-moon" target="_blank" style="font-size: 14px;font-weight:bold;">Mr. Cob meets Niel Armstrong on the Moon.</a><br />by: <a href="http://www.xtranormal.com/profile/8640480" style="" target="_blank">Mr_Cob</a></p><iframe id="xtranormal_Mr. Cob meets Niel Armstrong on the Moon." name="xtranormal_Mr. Cob meets Niel Armstrong on the Moon." style="width:480px;height:299px;" src="http://www.xtranormal.com/xtraplayr/13966226/mr-cob-meets-niel-armstrong-on-the-moon" marginwidth="0" marginheight="0" border="0" frameborder="0" scrolling="auto"></iframe>
    #58
  19. oppozit

    oppozit Banned

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    There is a gear reduction in the KMZ/Dnepr sidecar wheel but it is the exact opposite of the gearing increase at the differential. Look at this photo from the Dnepr Resurrection thread

    [​IMG]

    From L-R. Pinion and crownwheel final drive > planetary differential > big gear drives small gear > driveshaft > small gear drives big gear > stub axle turns wheel.

    Just a simple misunderstanding of the process. Also, your friends Ural is not a '70s model as Ural did not develop the Sportsman until the '90s for the export market to compete with the Dnepr 2WD.
    #59
  20. ReCycled

    ReCycled Been here awhile

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    The driveshaft gear reduction in the KMZ/Dnepr also achieves the sidecar wheel offset without the goofy angle required by the Ural design. It is kind of strange seeing it turn at 1/2 speed in the wrong direction though :1drink
    #60