VTA adjustment for VPI 10.5 tonearm

I am trying to get the VTA adjustment right on my reference superscoutmaster signature/10.5/koetsu rosewood signature platinum combo and right now classic records 200g and 180g set at "85" position seem right with a slight boominess in the bass. With thinner records (140-150g), it seems I need to lower it to around the "50" position in order to not have a graininess in the sound. Is my thinking correct or is there some other adjustment like adjusting the gain (I am using 30ohm load on my pass labs xono phonostage)? Any input would be appreciated. Also, how do I know the correct distance to keep the rim drive from the platter and should it be in the silver ridge or should I adjust the minifeet to have the rim sitting on the black part of the platter?
I have a JMW10.5/Aries 2 and my solution to VTA was to set the arm tube to parallel with the record surface using a millimeter ruler and a 180 gram LP, with the cartridge aligned and set for proper VTF, of course.

The last thing I want to do is screw around (literally) with the VTA tower for every record I play. This approach works perfectly for my tastes and the sonics are just right for every recording I play, regardless of thickness. Set it and forget it is my vote.

Can't help you with the rim drive however, I am still using the belt.
VTA is not as important as proper VTF. Make the arm horizontal first. I do this by taking an index card, folding it exactly in half so that the blue lines are horizontal. I now have a tent/guage..so that if I get way down to avoid parralax errors, I can make sure the arm is absolutely horizontal. I know it's a pain to continually adjust the 10.5i for VTF, however, suck it up and there will be a magic downward force that will be better than any other. Once you have the best possible sound from VTF (make sure that azimuth is set correctly..if you are unsure ask) then you can fool around with VTA. I found for my cartridge, it should just be very slightly down in the back. Also, experiment with damping. Just use 1 or 2 drops of the oil at a time. The sound will get better and better, and then one more drop, and it gets a bit worse. Use a toothpick or Q-tip and take out that drop. Also, the rim drive should make contact on the silver "land" portion of the platter. Do you have the soft rubber feet for the motor assembly?... Do not use the metal or hard rubber feet.
oops - forgot something on my post above.... For the best sound don't install/use the anti-skate gizmo.
Here I am again....by the way...85, 60,42, means nothing. All those figures are relative to your particular setup. When you spin the dial around 360 degrees you are back to the same number, but with a different VTA.
Keep in mind when measuring VTA on the 10.5i that the arm tube is tapered, so when you measure by eye using a straight edge, if it looks level it could be slightly raised at the back of the arm. I just set at level or slightly down for a 180 g. record and forget it.

I agree with Stringreen. Set VTF first and do that with the arm as close to level as possible. The index card trick makes it easier to judge this with the taperred arm. Depending on what scale you use, you'll likely have to raise the arm for this measurement to have the arm level. I f you don't have the arm level, your VTF reading could be off by as much as .3 grams or more. This is the equivalent of measuring VTF at the level of the record(as the expensive Wally scale does)provided you then set the arm level with the record again when you're done. Once the arm is level with the record, lower VTA by 5 at a time until you find the spot you like.
Stringreen is probably right about the soft feet and anti scate as well but I'm still messing around with those on my SSM ref. The rim drive seems to work best with very light conact with the super platter. Not much pressure is needed. Mike at VPI told me if the platter spins a little longer than the flywheel on shut off that's about the right amount of contact. Also, where the platter runs the fastest is another indication that contact pressure is good. The drive belt does need to be in the "land" between the grooves in the metal area and probably best as close to the middle of this metal area as possible. Luckily, raising and leveling is easier with the mini feet than the older cone feet. Probably the mini foot's best selling point in my opinion.
The table was set up for me by music direct. They recommended similarly and have set VTF at 2.3gr and have already calibrated azimuth and set the VTA for a 180gr record and everything sounds good with it. I am not using any damping fluid or the manual antiskate device (I only put one clockwise turn on the lemo connector as recommended and it tracks pretty well even though my cartridge is somewhat old). The arm tube looks parallel and the back of the cartridge looks slightly raised when a thinner record is being played so I thought lowering the VTA from 85 to 50 would help. It certainly sounds better that way. The same is true of people who recommend setting the loading for my cartridge at 200-300 ohms when it sounds good at around 30ohms and too grainy if set higher. I have been adjusting according to sound and less so with precision measurements. I am quite new when it comes to fine tuning LP playback equipment and I appreciate all of your help guys.
One more thing Stringreen, there are rubber feet on the rim drive but how do you tell what is hard and soft when it comes to that? there seems to be some give to it but not much. Would it help to put felt under them?
Powerdoctor..the new VPI feet for the rim drive are very clearly soft. I found this to be very important for the rim drive to operate at its best (I'm sure next week there will be something to make it better).. anyway, the felt under the harder rubber, or metal feet work to some degree, but if you have a rim drive, I advise you to ask VPI for the new soft feet. There is a new "rubber" ring for the rim drive coming soon.
By the way...my point about the VTF setup is this. For each cartridge, there is one "best" VTF. I believe that tracking force is different for every single cartridge. The manufacturer might specify 1.5-2.5 grams, however, within that range, there is one and only one perfect tracking force for that cartridge. A VTF scale is not needed except to be sure that you are in the manufacturer's range, however, experimenting by ear by adding or reducing SLIGHTLY the VTF will reveal that magic spot. There are some arms (VPI et al) that once you get that magic spot, you have to readjust other settings. I can't tell you enough that if you want to know the real magic hidden in those groves, you can find it with this very careful setup.
When running your table without the anti-scate do you use the wire twist or just nothing? I know in the past you have felt that the wire will fatigue and the twist will loose it's effectiveness. I'm still trying to talk myself out of the anti-scate off and on but currently am still using it at about as light a weight as it will operate without the lever falling over as the stylus reaches the center of the disc.
Hi Sonofjim... I use nothing for anti-skate at all...not even the Twist (Chubby Checker notwithstanding). I know that VPI arms can be a pain to adjust, but if you are inquisitive..just detach your monofilament to detect any difference. If you hear no difference why use it?? Then remove it from the arm, listen carefully, and I think you will hear a cleaner, clearer presentation.
As anyone out there tried to fit a VPI 10.5i to an Avid deck? I am just doing this and at the powest VTA setting the arm is still quite high at the back thus not being able to start with a level setting
Disagree on the 'parallel arm tube' method.

Ultimately, SRA, not VTA, is the final arbiter for tracking a groove with a stylus, and many factors other than the arm tube influence SRA (angle that the cantilever exits the cart body, cantilever compliance and length, stylus shape, attachment of stylus to cant, etc.) I use a 30x magnifier, and my 'Littlelight' as a backlight, to initially set the SRA as closely as I can to 0 degrees (at 90 degrees to the record). I usually find that slightly raising the back of the arm provides the best sound, but my VPI 12.5 arm (like your 10.5) makes it easy to document repeatable settings.

I do agree, though, about making your settings on an 'average' thickness LP, finding a sweet spot, and then just playing some music-setting VTA for all records is way, way beyond my fussiness threshold, and borders on putting a premium on hi-fi effects, not on the music. IMO, of course.
Perhaps I have not quite explained my problem correctly.I am glad you know what I am trying to do, but what is happening is that on my lowest setting the back of my arm is SO much higher than the tip I think I am missing out on my optimum setting which could be somewhere between here and level, I totally agree with your thoughts but I am so far away from the 90degs to the record
Colinb-I was responding to the general issues of VTA/SRA brought up by the OP. You might be wise to start a new thread with your issue, but it sounds like you have a top-of-plinth/armboard to top-of-platter mismatch, probably due to the thickness of the Avid platter relative to the thickness of VPI platters.

Obviously, if the armboard was too low, it would be a simple matter to raise the arm. But in your case it might be much more difficult to lower the armboard. I'd start with communicating with an Aries dealer and/or distributor, and then, if necessary, ask here (and at Vinyl Asylum) for help.
I need to lower the 10.5i arm at the pivot a bit. With the VTA tower all the way down, my cartridge is still a tad high at the end.

I see a set screw next to the pivot. Not sure what moves though. The actual column or the pivot itself? Want to make sure before I adjust this.
Disagree on the 'parallel arm tube' method.

You can disagree all you want but this is the method which in some cases renders best results with the least amount of headache. For example, the Lyra Delos is manufactured to sound best (i.e., achieve the desirable SRA) with the tonearm parallel to the record surface and then tracking at 1.75 grams. I followed Jon Carr's instructions to that effect and have been enjoying the music since day one.

I use a 30x magnifier, and my 'Littlelight' as a backlight, to initially set the SRA as closely as I can to 0 degrees (at 90 degrees to the record). I usually find that slightly raising the back of the arm provides the best sound, but my VPI 12.5 arm (like your 10.5) makes it easy to document repeatable settings.

M. Fremer wrote a very interesting and informative article in the June 2010 issue of Stereophile discussing SRA, VTA and VTF. Apparently the most optimal SRA is actually 92 degrees, not 90. He did, however, recommend starting with an SRA of 90 degrees, to be fair. Another critical consideration is the fact that getting that perfect 92 degree SRA is very, very tricky. I doubt a 30x magnifier is enough to determine whether you did in fact set it to 92 degrees (he recommends a digital USB-based microscope). Why? Because what matters is not the angle of the stylus SHANK, but the CONTACT AREA. You need to know your stylus profile's contact patch to get it right. In some cases, "the shank might have to be pitched far forward in order for the CONTACT AREA's SRA to be at 92 degrees."

I do agree, though, about making your settings on an 'average' thickness LP, finding a sweet spot, and then just playing some music-setting VTA for all records is way, way beyond my fussiness threshold, and borders on putting a premium on hi-fi effects, not on the music. IMO, of course.

We're in total agreement on this philosophy.