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Thread: V-Rod 250 for $250, a do-it-yourself Phat Tire kit.

  1. #1
    Robin Oury, UE's owner MonsterMaxx's Avatar
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    V-Rod 250 for $250, a do-it-yourself Phat Tire kit.

    My PM stuff arrived and I was eager to fit the 250 in my Vrod. The rear end at this point is stock other than some trimming of the belt guards to clear the Avon 200.
    My original intention was to cut the swingarm in half and make it wider and re-weld it. Then make 2 new longer axles.

    To begin with I took it fully apart. Then began fitting parts to the bike. I measured and created the axles in a CAD system in anticipation of making drawings.

    Somewhere around 1 AM it dawned on me that I could fit the 250 without having to make the swingarm wider. It just needed to have the tire and swingarm pushed left as far as possible.
    Somewhere around 4 AM the ebay swingarm, a grinder and a very dirty me had a verification that it would work. It wasn’t pretty, but it was close enough that I believed I could make it work.
    The PM CFR hubs do not work with a 250. Belt hits the tire hard. I was able to space the pulley out for mockup, then turned to a friend of mine in Calif who has a machine shop and could make spacers easily.



    Back to the computer I replicated what I’d done with the grinder and completed drawings. The end result was that it said I had 3 extra millimeters. Great! That’s a good safety margin. You might say that’s not very accurate for a computer, but what you have to remember is that getting an accurate representation of the Vrod into a computer is no easy task. There’s not a straight line or normal plane in the whole darn machine.



    Off I went w/ swingarm and other parts in hand and left them at a machine shop I frequent. A week later I call and find out he’s been hit by lightning and every machine in the shop is fried. So off I go in search of another. I stopped in at the guy who does ceramic coatings (is also an engine builder) and noticed an old Bridgeport in the back. That’ll work. We setup a time. I didn’t want to leave it with him, but he said he was just going to try to figure out how to hold it.
    When I showed up for the delayed 3 times appointment he’d just finished making the last cut. All of them wrong. Darn I wish people would do what they agree to do. He was not to cut on it until I got there.

    Oh well, I can still make it work.

    My spacer parts (for the wheel) finally arrived and it was time for another mockup.


    While I’d done my best to simulate the belt and guess correctly at my spacer I’d hedged my bet and instead had 2 spacers made that when added together made up what I’d measured. Turned out to be a good thing as first setup showed lots of extra room, and I needed it for wheel so I cut it back. As it is now, if the belt rides full right in the pulleys it’s just barely rubbing the tire in one spot (tire wobbles a bit.) In the next version I’ll put just a touch more space back or maybe I’ll just razor the edge of the tire. It’s rideable at this point, though I’m watching it.

    Back on topic here,

    Next would be what to do about the pulley. The answer is simple, put the pulley on the other side of the flange

    and machine the face down to achieve a concentric locater for the flange and to pull the pulley back inline with the belt.
    I setup the bike as far as I could and got the belt tracking, then took a measurement of the gap between the edge of the belt and the flange face on the pulley.

    Pulled that off and again went off to a machine shop to face the pulley and cut the bearing spacer tube down a little.
    {sorry, no pic, will get one next time}

    That night was a late one fitting things up for the umpteenth mockup. When I finally had everything suspension related installed and working I called it a night, tomorrow would be soon enough for the fender.

    note: parting line is not centered in the tire, do not use as a reference for centerline

    It’s time to fit the fender to clear the tire when it’s fully compressed. I compressed it as far as it would go and measured the center to center distance for the shocks, got 10.25”. Spec on the PS440 is a min length of 10.38” so it’s deeper than it should go with the shocks on. I'll grind a little 'extra' room for impact overcompression later.


    Next time I take it apart I'm going to grind the frame where you see the marker to remove the sharp point and give just a little more clearence. I've left them alone until the end of this project as reference points.

    It’s pretty obvious from looking at the inner fender there’s no way to spread it enough w/o cutting some relief for the material.

    Both sides were notched. Then working with a port-a-power I got off ebay for $10 I started spreading the fender. This thing is strong! I tried the precision ‘Paulie stomp’ method as shown on OCC, but only cracked it necessitating a larger notch to remove the crack. In the end it was the port-a-power that got the job done. Kept working it back and forth pushing on the bolt holes using bolt heads to catch the feet on the ram. A good thing I didn’t try it the night before. It was a real biatch.



    The fender skin was pretty easy, just held it up against my chest and pulled on the edges until it was the shape I wanted.

    I’ve taken it for a ride and it rides well. One shock is rubbing the belt guard, but that’s because I need a longer upper shock bolt and won’t have it until Tues. Otherwise it’s ready to rock. I’m going to take it down and have a guy I know confirm alignment before I make any further decisions on spacing (like some more for the cush drive.)

    Once I do that I’ll setup my chrome swingarm and modify it. Nice part is all these mods should be hidden so I won’t have to re-chrome.

    Along the way I did a day or so of FEA (stress analysis) to verify that I’d not compromised the strength or made it dangerous. What I found was that in all cases the swingarm fails in other places before it does where I’ve made modifications.
    One very interesting fact is that this generation (pre ’05) of rear axle is quite weak. A force of aprox 2000 lbs on that side will cause the axle to completely fail. When using the ’05 and later Ø1” all the way across axle, it’s taking nearly 5000 lbs before failure. This will be incorporated into the final install with the chrome swingarm and one-piece spacers.


    From an engineering point of view this modification is just as strong as stock. While it’s true these mods do make the area modified weaker than original other areas fail prior to these points so the changes in strength are not called into question. By the time you are getting swingarm failure you have much bigger problems (broken axle for one.)

    By increasing the axle to 1” all the way across and adding another mount for the swingarm the strength would be increased.
    "That which doesn't kill me, makes me stronger." - Nietzsche

  2. #2
    Robin Oury, UE's owner MonsterMaxx's Avatar
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    How To put a 250 tire & wheel in a Vrod for $250

    First the swingarm needed to be modified in 7 places.
    1. Right side main bushing, allow swingarm to move left.
    2. Remove draft on right side to clear tank bracket
    3. Remove draft to clear pulley
    4. Machine shock ear to allow belt guard and nut to clear pulley
    5. Machine new shape into brake arm to clear wheel.
    6. Machine underside of brake arm to clear PM brake arm.
    7. Machine RH ear to clear PM brake arm.

    Note: In hindsight making a whole new brake arm could eliminate 6 & 7 and look cleaner too.


    The pulley and flange need to be modified. Flange to remove sharp outer edge so it will seat correctly and face the pulley to move it back in-line with the belt.

    The swingarm axle needs to have it’s shoulder cut back to allow it to go deeper.

    The PM brake arm needs a slot for the rotor bolts and also needs to have the catch shortened a little so I didn’t have to cut as deep into the swingarm. Again, a custom one would be better.

    The belt guard needs to have the support that goes to the inside removed. It will only mount at the front and the shock bolt. It may also need some clearanceing for the tire. Mine did not as it was already fit for the Avon 200. There may be some mods needed for the lower, but I’ve not gotten that far yet. When I held it up there it looks like it’s going to need some clearance for the wheel like the brake mount did on the other side.

    The belt guard mounting bushings needs to be slotted to move the belt guards outward.

    3 small spacers and longer bolts will get the pulley cover back in place.

    The inner fender needs to be cut and spread.

    The outer fender needs some gentle massaging.

    Spacers for shocks & axles and one longer upper shock bolt are the only ‘purchased’ items.
    "That which doesn't kill me, makes me stronger." - Nietzsche

  3. #3
    Super Moderator imaxx21's Avatar
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    awesome...a SuperV
    -Crash

  4. #4
    ¿who flung poo? Spookypoop's Avatar
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    sweet, looks awsome with the 250 in the rear!
    -Yea....

  5. #5
    Robin Oury, UE's owner MonsterMaxx's Avatar
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    "That which doesn't kill me, makes me stronger." - Nietzsche

  6. #6
    now 728maxx ws7maxx's Avatar
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    Very Cool !!!

    Is this a kit you will be selling?
    Gidddy up.........

  7. #7
    Robin Oury, UE's owner MonsterMaxx's Avatar
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    I found someone in town with the bolt I needed so I dug in and finished it today.

    Figured out spacing for the shocks and got the lower belt guard and pulley cover installed. I'm now up to 8 mods to the swingarm.

    Finally got the rear brake blead properly.
    With the dual 6 piston calipers and 13" rotors up frontPM caliper in the back and Lyndall pads all around this bike'll stop hard. Stomp!

    Then I went for a ride.
    It's very agile. I expected to really have to wrestle with it. It was anything but that. I found it razor sharp, more than happy to dive into a corner. My only reservation is that I didn't feel like I had as much traction when it was leaned over. I stayed smooth on the throttle and had no problems.
    This is not a beginner's bike anyway.

    I just luv the look. So rigth for the V-Rod.
    I'm a very happy camper.




    Here it is with guards and cover in place
    "That which doesn't kill me, makes me stronger." - Nietzsche

  8. #8
    Veteran SupermaxxRich's Avatar
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    Looks good, way better than the stock tire. Just too punny for me

  9. #9
    Veteran RD Racing's Avatar
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    That's SUPER DOPE!

  10. #10
    Super Moderator Booyah's Avatar
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    That is one badd ride for sure! Nice work you have put into it too---all worth it at the end
    The Largest State in the USA---
    Alaska = 650,000+ Sq. Miles

  11. #11
    now 728maxx ws7maxx's Avatar
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    That is just a killer look. Good effort!
    Gidddy up.........

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