M7 Skid Q....again

[brianidaho]

I'm finally getting around to working on my M7 skid and getting it installed in my machine. I'll be using my MPI drop bracket as a template for the new ones, but need one piece of information-what is the proper distance from the center of the front mounting bolt to the rear one? I seem to recall seeing 34 1/4 mentioned in an old post, but can't find if for the life of me.

Also, does anyone know if the MPI brackets mount via existing rivet holes, or if new ones would have been drilled? My sled came with them, I don't have the stock brackets to check out. Not a big deal for me but if anyone else needs a set of brackets I could have an extra set or 2 made, so long as the mounting holes would work for them.

Thanks.
Brian

 

[Powder Nomad]

Mounting bolt distance

Hey Brian... think it's 31 1/4... saw that here from Johnny Rocket:

http://www.ty4stroke.com/viewtopic.php?t=38197&highlight=skid+install

Nomad

 

[Rx1M5]

I think the actual measurement is 31 3/4" at least that is what we are using and I took it off an M7.

Rx1M5

 

[freelheeler]

i'm also in the process of installing an m7 skid... i'm using 31.5" center to center however its a bit difficult to align both sides. so what i've done to check my work is install the front mount bolts and spacers and braced the rear mounts at the pre measured locations and just mocked up the alignment of the rear bolts. a few slight adjustments and it all seems to make sense. in essense the skid uncompressed should confirm the dimensions

the other question about geometry is the height of the tunnel rails from the ground? measuring from a known point (where the stock rail connects to the hartman tunnel extension) i'm at 19" from the ground, that's with a 2.25 paddle track. i've discusse this with Kachess and he discusses the center of gravity of the sled in his post and this measurement addresses how far the skid is 'sucked' up under the sled. Kachess runs the stock rails and holtz suspension so it's difficult measuring apples and oranges. for folks with ride time of the m7 skid where are you set??



thanks

 

[brianidaho]

I'm heading out to the shop to work on mine today, just got the Holtz relocation kit yesterday. We'll see how it goes. Thanks for the information.

As far as getting the measurement transfered, I think someone mentioned taking a board, drilling a hole for the front mounting screw and measuring and marking the distance on the board to assist transfering it to the drop brackets-I'll be giving it a try and getting the bracket into CAD.

 

[Jonny Rocket]

The center to center is 31-1/4" I wouldn't go any longer than that 2nd to the geometry of the AC skid. You don't want to mess with it too much. When you go to put the AC susp. in it will look like it will not fit. You have to undo the large spings from the rail so the susp compresses. Then the rear mounst will go into place. Still a little tricky at first but it will go in. This will ensure the suspension is compressed correctly and will therefore work correctly. You also want to watch out for the rear shock. The bottom mount tends to rotate around and fall into the incorrect position.

This is a great post that goes over the instalation.

http://www.ty4stroke.com/viewtopic.php?t=2845

Hope this helps.

J.

 

[brianidaho]

Thanks Jonny. I'm trying to get some pics as I go along, maybe I can post a step by step if anyone is interested. I got the Holtz kit in, piece of cake. Also pulled the old skid yesterday, man that M7 sure is a bunch lighter than the Yammie skid.

Bri

 

[Jonny Rocket]

No problemo.
I am sure the step-by-step would help a lot of felloy TYr's. Seems this is a pretty popular mod.

J.

 

[brianidaho]

I have been taking measurements from the MPI bracket and remodeling the profile in my CAD system for a check. I want to revise a few things and send the file out for waterjetting.

How far did you drop your bracket below your tunnel, or more specifically your running board coolers (easiest to pull a line from)? I'm thinking around 6" to have plenty of room to adjust the drop.

Also, did you just go with 1/4" 6061? The M7 suspension is almost identical in width to the inside of the tunnel, 16 3/4-16 13/16 or so, I'm thinking the brackets should be offset to avoid springing the tunnel to get the skid in. At the least I might countersink somewhat on the inside of the bracket where the arm mounts.

 

[snomadTT]

I made my drop brackets out of 3/8 aluminum. I left about 7" below the coolers - too much. I have three holes in my brackets for adjustment and am in the one closest to the tunnel. Now - I had to set the M7 skid back about 2" in my Vector to get it to accept the 162" track, but I need all the weight transfer I can get. If I run the suspension in the lower holes (raising the bumper height) I end up with too much weight up front.

The offset concern you raise should not be an issue - it isn't for me. In fact, I have to add shims between the tunnel and M7 skid on the front arm mounts as it is an inch narrower than the tunnel.

Understand - I started with a 2005 Vector. Picture attached for reference.

 

[doo_man]

I took mine to a local Fab shop and they put a 1/4" offset in them and they were perfect!

 

[Jonny Rocket]

I used 1/4 6061 and it fits pretty good. Little tight but it works very well. I don't think you will need an off set. Frosty and I both have AC skids with the 1/4" bracket w/o any issues.

Also I think 6" below the cooler is too much. I am at ~5" and it is too much. I have 4 holes to mount the susp. on. Each are 1" apart. The 1st is 1" from the cooler. I ended up mounting mine on hole #2 (2" from the cooler) which seems to be about right for me. I think the max you would need is 3" from the cooler so if you made the bracket go 4" down from the cooler you would be OK. But that is just me.

J.

Here is a pic for reference:

 

[brianidaho]

Here's the CAD image of the template. I went with 4 1/2 below the cooler (line on the part). The little tab on the left side is in line with the straight on the right side, it's just for fixturing and laying out rivet and screw holes, and gives something to locate off of if I put it in a brake and form an offset.

Thanks for all the input guys, TY is a great site for helping each other out.

If anyone else wants a set of the brackets, let me know, more sets should be cheaper at the water jetter. I should have them quoted the first part of next week.

Bri

 

[Jonny Rocket]

That looks great!! Should be perfect.

J.

 

[brianidaho]

Well, I picked up the plates from the water jetter Friday after work and made a run to Harbor Freight for some transfer punches. Sunday I went to work transfering and drilling holes. The whole project went very well, nothing to it. The CAD layout worked out very well, the holes I put in were just a touch undersize so I could clean them up on the drill press. The 3 holes for skid mounting in the model came out fine when I checked them with the 31 1/4 inch "layout board". I need to pick up some more fasteners and rivets tonight after work, as well as mount my scratchers.

Now that all this work is done I hope the track fits-I have a 159 with 153 rails, which I understand will work out to 162's...hope there is enough travel in the track tensioner. If necessary I can put on smaller wheels.

If anyone needs a cad model of the brackets let me know. You can probably get a better deal on waterjetting than I did.

Brian