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Pros and cons of changing Maxim rear wheel for a Seca one?

Discussion in 'XJ Technical Chat' started by Minimutly, Apr 11, 2018.

  1. Minimutly

    Minimutly Member

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    is it worth swapping - besides the aesthetics, what are the advantages? I assume a smaller height tyre on the bigger wheel gives a similar rolling radius?
     
  2. XJ550H

    XJ550H Well-Known Member Premium Member

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    gives you lower rpm at crusing speed and a slightly higher speed at top end

    your quickness may slow slightly do to larger circumfrence of rear tire
     
  3. Minimutly

    Minimutly Member

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    What about handling, does this affect how the bike will handle in the turns? I would have expected a big tyre to deform more, thereby giving less precise handling. I also believe, but admit to not checking this, the smaller wheel uses a bigger (higher profile if you like) tyre?
    Thanks
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

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    can not speak to handling .

    I know my 550 maxim tire is about a half inch shorter when put up to my 550 seca tire
     
  5. Minimutly

    Minimutly Member

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    Ok, need your help here.
    My maxim rear wheel says it's a j16 xMT 3.00.
    There is one on ebay (from a seca?) which is a j18 x MT 2.15
    Now if I go to this seca wheel, will I be needing a narrower tyre? Is this the only width in this diameter?
    My online data tells me the seca rear tyre should be 120/90/18, which is slightly narrower than my maxim rear I believe. The thing is the wheel on ebay is quite a bit (too much?) narrower, do I have any other choice in swirly alloy?
    Thanks,
    Huw
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

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    130/90 130mm tall 117mm wide
    120/90 120mm tall 108mm wide by ratio 9mm narrower

    you could go up 1 size tire for the seca rim
     
  7. Minimutly

    Minimutly Member

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    I could go up 1 size for the seca rim? Hmm, Forgive me, thinking about this. Up 1 size from?
    My concern is that the seca rim is narrower than the maxim one? Does this mean i'll have a narrower tyre, if so, is this a backward step? If the numbers on the wheel are correct the wheel is .85 inch narrower, 21 plus mm narrower, doesn't feel like a step forward to me?
    So, can I run a 120/90/18 without it moving around more than my current 130/90/16?
     
  8. Minimutly

    Minimutly Member

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    It looks like I'll have a 9mm (thanks 550) narrower tyre on a 21mm narrower wheel. Ideally I would like a lower profile tyre on a seca diameter, maxim width wheel. Asking the impossible by the sounds of it, unless there is a swirly 3inch wide 18 inch wheel.
     
  9. XJ550H

    XJ550H Well-Known Member Premium Member

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    120/90 120 seca tire size you go up 1 size larger in height and width
     
  10. Minimutly

    Minimutly Member

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    Is there no other rear wheel that would do it?
     
  11. Minimutly

    Minimutly Member

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    Ok, I'm being pedantic about this, but I figure if I'm going to change something I might as well get it right.
    As you all probably know the 750 and 900 models all run the same 120 90 18 tyre. However, it seems the 600 seca rear tyre is the same size tyre, but the wheel is a 2.5 T18. Problem is, this wheel is not a swirly, and not a shafty....
    The fact that Yamaha deemed it needed a 2.5 wheel does tell me something though.
    Carry on looking, I think
     
  12. Minimutly

    Minimutly Member

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    Had a good look around on this. It seems the only option is to go with xj900 disc braked wheel. This turns it into a bigger project than I need right now - replace swing arm, hydraulic brakes, front wheel to match etc. Perhaps when it's up and running perhaps a phase 2 will be in order. For now the seca wheel with a smaller tyre is what I think I want.
     
  13. kerriskandiesinc

    kerriskandiesinc Active Member

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    Why?
    I've owned both a Seca and Maxim, they both handled about the same....ok Maxim was a little less sporty, due to the 16" v 19" (F/R) mismatch, both maxed out around 130...I couldn't say the revs increased/decreased so noticeably, for any given speed....
     
  14. Ketchup

    Ketchup Member

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    Good afternoon @Minimutly

    While I cannot speak for the exact US Seca model wheel and tire combination, I can speak for having swapped out a 1981 Maxim 550 16" rear wheel for a 1982 Seca 550 Euro 18" wheel. The swap was 1-to-1 in that everything from the Maxim 550 (brakes, axle, nuts, cush drive, ect) all fit the Euro Seca 550 18" wheel without modification.

    As for the overall tire/rubber information:
    -Euro Seca wheel did not deliver with rubber
    -Rubber was hand selected by myself to fit specific criteria based on available tire choices
    -Conversions performed based on previous Maxim tire that was on the bike and how I wanted a new tire to fit (Conversion image attached)
    -Previous Maxim 16" wheel/tire was size 130/90-16; approximately 1/4" clearance between tire and chain - not ideal for me.
    -New rubber installed on the Seca 18" wheel was 120/80-18; approximately 1/2" clearance between tire and chain - much better for me.

    Advantages of swapping to an 18" wheel:
    -More rubber options
    -no more rinky-dink 16" wheel
    -options to upgrade 18" wheel bearings with ZDD part deployment while still running that rinky-dink 16" wheel
    -Aesthetics

    Similarities between the wheels:
    -Braking
    -it spins

    Disadvantages:
    -I can ride it a bit more aggressively
    -PlsDontTellMyWife

    Otherwise, my butt-dyno can not measure or observe any negative handling characteristics from this combination.

    Pic #1 - tire calculator
    Pic #2 - tires ordered
    Pic #3 - Euro Seca 18" swirly wheel

    Skol,
     

    Attached Files:

  15. Minimutly

    Minimutly Member

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    Now then, that was what I was looking for. Thanks ketchup.
    The main reasons for me to want to do this are twofold - aesthetics, my maxim is destined to be a flat tracker, and a fat rear tyre is not in fitting with this. Secondly, the fat tyre is not conducive to leaning hard on in the twisty bits.
    Now, the issue I've found with the "euro" seca 650 swirly wheel is that at 2.15 It's a tad narrow.
    The only fix I've found is the 900 seca, but this is a square parallel element thing - like the 750 turbo, and to make things worse, it's a disced wheel. But at least its wide enough to stop the tyre moving around. Fitting this swing arm/wheel combo looks possible, but will kind of spoil one of the original reasons for doing this, to some degree but not totally.
    So it's the swirly narrow wheel for now, we'll see about the xj900 wheel later.
    Thanks again.
     
  16. Ketchup

    Ketchup Member

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    I would also like to suggest the Yamaha xv920rh rear wheel; chain drive.

    Seemed like a limited production model but the rear wheels do crop up on eBay from time to time.

    The Yamaha xv920rh rear wheel assembly utilizes different part numbers than the 550 platform all across the board. However, if you were to obtain a complete xv920rh wheel assembly (brakes, drive hub, ect) it may just “swap over”. Outside of speculation, my research stops at the above. You might gain a larger drum brake out of it. Had spent some time over on the XV boards and XJ wheel swaps seemed to be the norm for the XV platform - so, potential for it to be a true swap.

    I was not willing to go the xv920rh rear-wheel-route and opt for a euro 550 18” wheel. Nuthin’ fancy here - just a dad wanting to run some more aggressive tires!

    Xv920rh rear wheel eBay part example:
    https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/291732751465

    Hopefully my above model number references are correct. Might be a bit wider rim than the Euro 550 Swirly.

    Skol,
     
  17. Minimutly

    Minimutly Member

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    Chain drive no good for me, mine is a shafty. Had a look at virago shaft wheels, too small diameter.
    Thanks
     
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  18. Ketchup

    Ketchup Member

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    My apologies @Minimutly - I was under the impression you were a 550 chassis seeking a chain drive wheel.

    You still have options.

    My success was had with BoonStraParts in the Netherlands - North American Market not all that great for sourcing individual parts it seems.

    Here's one example of an 18" shafty wheel: https://www.boonstraparts.com/nl/on...650-16g-achterwiel-2-15x18-1982&ID=B10000WLTO

    Additionally:
    https://www.boonstraparts.com/nl/on...-1982-xj750-15r-achterwiel-1982&ID=B10000ZHKC

    Expect to pay about $60 on shipping. They're also pretty good with answering questions same day. If you do decide to order - be conscious of your shipping address, as the Netherlands puts the road name first, and not the number. USPS was able to sort this out for me - but it felt a bit hairy there for a bit. Would also recommend working your way through all XV/XJ models until you've found a wheel that matches your desired criteria (shaft drive, diameter, width, ect). You can somewhat validate parts interchange by using any of the online parts places, finding the part and matching part numbers between the two different models - PartsFish.com has diagrams with zoom. Babbits as well.

    Skol,
     
    Last edited: Apr 18, 2018

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