Long motor arm should be used to swap between pneumatics and skate wheels. My new motor mount with stabilizing crossbars is universal to any size motors and wheels. More details can be found at Janux-esk8.com
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Hey, looking for some advice from others that have these mounts.
I really thought the dual idlers on these mount would solve belt skipping during breaking. On my commute today It worked for 10 minutes and only on the tightest possible configuration and then it started skipping just as bad 
(during my testing last night I found that only at the tightest position it stopped skipping, even at 1mm less than the tightest it skipped)
So now I have 4 of these mounts, more pulleys and 8 belts and they skip a lot for me. The second set is for a build that Iām just starting. Whatās the next thing I can try to stop skipping? If these donāt work it will be a lot of $ wasted.
Some stats: gearing is 14/36, my weight without any gear on is 225lbs. 12mm dual belts.
Going 15mm is not really and option as it doesnāt fit the Caliber IIs with 6355s and I would have to spend even more money on Pulleys?
(The belt is not touching itself but itās as close as possible)
Hey Gihad, At 225lbs running 12mm belts, itās inevitable to get some belt skipping during breaking. The rubber teeth of the belts do not have the capacity to completely lock onto the pulley, especially on a hard break. Similar to a car slamming on the break bearing down at 60mph comes to a streaking stop even with anti-locking system.
The positive of running idlers is prevent tooth skipping during acceleration, rides, and improve breaking. Have you try compare running with and w/o idlers?
With the 320 belts with no idlers vs 330 belts with dual idler Iām getting about the same amount of skipping, a lot of it. I never got belt skipping during acceleration, not even on the DIYEBoard drivetrain which was I wanted to improve upon with these.
Iām not even running powerful breaks here, on the other build that itās also supposed to use this same drivetrain the motors are a lot more powerful (dual 6355), so I guess it might be worse there?
It appears you still have some slacks on the belts. Install a belt that is 5mm shorter than your current size.
Good eye @marcmt88 . I tried 320mm belts with just 1 idler (required a lot of force to install) and it gives a VERY tensioned setup, almost like a guitar string 
but there was no skipping during my short test. Tomorrow I will do a longer test.
I will try the larger motor pulley with the 330mm and if I can find I will try 325mm belts. Thanks for all the help here and via email.
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I get zero skipping during breaking on these with just a single idler bearing, brake side. Im 200 pounds and I am using 15mm belts. The motors are 5065 racestar, so not as much torque as 63mm motors.
A larger motor pulley will definitely help. I have a theory that your 14t pulley is worn, that might be the cause. Can you take a photo of it?
I am using 18t / 36t so I think the large motor pulley helps me a lot. Below 15t is not stable as they wear out too fast and skip more easily. Unless they are steel then they last good.
Motor pulleys are steel and new. The key difference with your setup are the 15mm belts. 18T would also help.
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Am I blind? I donāt see this mount/kit on your website. Unless itās only available as the completed drivetrain?
What about a kit with the āDual Motor Mount with Crossbarsā and the other bits like some of your other ādrive systemā kits (pulleys/hardware/pulley/cover/etc)?
Kit price for āAnodized Dual Motor Mount with X-Barsā is $330, includes:
- āAnodized Black Dual Motor Mount with X-Barsā
- Dual POM idlers on each motor arm (4 totals)
- Choice of 14, 15, or 16t steel motor pulley x 2
- Choice of 30-40t x 16mm POM wheel pulley x 2 (other sizes available at additional cost)
- Appropriate sized 15mm wide belt x 2
- POM pulley covers x 2, not 3d printed
- Installation hardware
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Update on my issue with belt skipping. Iām using the long motor arm mounts. I Was able to eliminate skipping with dual 12mm belts by using 14/36 gearing with 320mm belts and one idler pulley. In this setup the belt is very tensioned and range is reduced but no more skipping.
I also got another set as well for a build that I just finished, also with long arm and caliber IIs but with 16T/36T gearing (bigger motor pulley). in this case Iām using 330mm belts and no idlers at all, itās also a tight fit and there is no skipping! At the end of the day it seems that belt skipping has more to do with belt tension. Unfortunately the covers can not be used with if you donāt have the idlers moving the belts down but Iām happy I was able to eliminate the skipping.
@marcmt88 Now that the belt skipping seems to be fixed Iām making a separate message for this other issue that I have. On both my builds that uses the Caliber II mounts they eventually get ātiltedā. I wonder if there is anything I can do other then DIYing a cross brace to stop this from happening. The bolt on the C-clamp is torqued down to the maximum, thread locked and waited 24 hours before riding.
I noticed the c-clamp never really sits flush on the caliber II mounts so I wonder if this can ever work.
It appears that your hanger is bent.
The Caliber IIs? I think itās just the lens distortion in the picture. Whatās causing the motor arm to be tilted is the c clamp. I wonder what I have to do for the c-clamp to not move.
How tight is the c-clamp supposed to be? Iām not sure if I can torque it down any further. Are the 2 ends of the C supposed to touch each other?
This is how itās setup right now:
Mine do not touch at the tip. I donāt think they need to.
To confirm whether your hanger is deformed or not, switch out the clamp. Same thing happens with the other clamp, your truckās hanger is not symmetrical.