This does not fit a Caliber II truck very well, you will need to file the hanger if you want to get this a good amount closer to the center of the truck. You NEED thread locker and even then it might still become undone while you are using it ( both the screws mounting to the truck and to the motor. ) But if you get those things done for the price I got it for ( 25 bucks ) about the best value I could really ask for.I paired this mount with a caliber ii knockoff (mboards trucks 7in). What I found was that the mount collar would fit for the first inch, then the hangar became too thick and wouldn’t allow the mount to be put any further in. I ended up having to file down my truck hangar to be able to get the mount in deep enough so that it doesn’t hit the pulley. As others have mentioned the mount being too loose, and mine was too tight, the mount could either have poor tolerances when manufacturing or the trucks I used were poorly made.After getting the mount on, the overall assembly is amazing. The slots for the motor bolts made it extremely easy to get the perfect belt tension when compared to other mounts on the market. I did have initial issues with the mount not correctly aligned with the truck but that was because of my very imprecise workmanship when filing. Overall, very pleased with the mount and if I plan on doing a dual motor in the future, this is my go-toMounts work well. I did a rebuild on my electric board and ordered these mounts, these pulleys (https://smile.amazon.com/gp/product/B07FCVY4SF/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1), and these trucks (https://smile.amazon.com/gp/product/B00NY3Q5Q8/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1). See those listing for my review on them.Anyway, the mounts worked nice. I ended up purchasing 2 of the 50 and 63mm ones because I was unsure which one I needed. The mounts are the same size with the only difference being the distance between the actual motor mount holes. I forgot to take a comparison photo with the actual measurements of them because I could not figure out where the 50 and 63mm actually came from. From memory the 50mm, which ended up being what I needed, had hole mounts about 26mm or so from center to center.The kit is good and comes with all the allen keys that you need to set it up. They fit the trucks I got perfectly, not sure why that one other review said they don't. The trucks tapper off as you get closer to the axial so I bet he did not slide them on all the way. The one issue that came up was that with the pulley I had just slightly hit one of the mounting screws. I ended up just adding another washer to give everything the clearance it needed. See my review on the pulley for more info. Another note is to use loctite (the blue one) when putting everything together. This not only makes sure the screws done back out but also give a little bit of lubrication when tightening everything down. This lubrication was needed to get the one big screw tight enough to hold onto the truck without moving.In the end all the parts worked together. It is no a DIY board unless you need to make some tweaks yourself.This is a great motor mount for esk8 building on Caliber II trucks. I have the same one I bought years ago on ebay but it seems to be gone now so I found this motor mount on Amazon and it's as durable as my last one. I use it for dual motors. When I finally tried to test it, it is very durable using my 6374 sized motor with 170kv & 2,900w power. The only problem I had was the vibrations of my board when riding and some screws on the motor mount fell. I didnt notice it for a few days after that time I rode. The seller gave me some extra spare of screws for it and I was happy about it. This motor mount is the only less expensive and durable for caliber II trucks I know of. Most motor mounts out there are around $80-$200.I'm seeing a few people complain about the size of the mount, but it's really the best option.I would rather have the D-clamp be just slightly too large and use a shim instead of it being too small and forcing me to grind down my trucks to fit. If I had to guess, there's approximately 1mm of difference between the truck and the mount.In order to properly mount it, I've placed a sliver of heat shrink between them to make sure the mount is tight when sitting on the truck, then I screw the tightening bolt to keep it completely immobile. Overall, this mount is basically the same as one you would buy from any of the DIY skateboard suppliers, the only main difference is the curved shape of the mount.(There's another review on here with photos where it looks like the truck is about half the size of this mount, and I can only say that that person probably bought the wrong trucks)Quality is fairly good and unlike other reviewers, these fit my Caliber II trucks perfectly. Not sure why others have issues, all I can think of is that they are trying to fasten the mount at the end of the hanger (wrong!) or bought the wrong trucks.One problem I'm having with the mounts is related to my dual motor setup. The spacing of the slots does not allow mounting in about a 10 degree range. Which of course is exactly where I need to be... right in that unavailable range.This is nice for a singe motor. but you can't get the angle you need from it for both sides. One of your motors will be perfectly placed while the other will have to be just a little lower and will get hit once in a while.My mount came loose from the vibrations and snapped but I sent a message to seller and he sent me a brand new part for free.Tips: Use Loctite!! As well I had to get a longer cap screw for the caliber mount and I used an impact drill to tighten it.Solid mount!