33 Killer Bees 2019 Offseason Swerve

HTD, GT2, and GT3 can all be intermixed.

See RCs post below.

Thanks for the clarification

Im not 100% sure this is right…

GT2/GT3 are likely similar enough, but I thought HTD was a distinctly different profile?

They may work but it’s less than optimal?

Correct, less than optimal.

Tooth profiles (HTD, GT, etc) are a game of thousandths, so as long as they’re all the same pitch (tooth spacing) they’ll work OK.

EDIT: I am wrong - check out RC’s post below and this explainer on GT2/GT3 and why it changes within product lines: http://gatesbeltsandapplications.blogspot.com/2015/10/whats-difference-between-gt-gt2-and-gt3.html

I wouldn’t necessarily mix HTD and GT profiles professionally, since I would likely run into trouble if I tried to submit a warranty claim, and mixing profiles will likely result in more belt wear, more noise, shorter product lifetime.

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This is incorrect.

HTD Pulleys can accept:
-HTD, GT2, GT3 Profile

GT Pulleys can accept:
-GT2, GT3

The GT pulley is not deep enough to accept the HTD profile. Also you will lose some strength when running GT belts on a HTD pulley, for FRC use case on most mecahnisms its not an issue. Currently our team uses only VEXpro pulleys and mixes and matches belts on them.


Do you mix and match belts purely for sizing reasons? Do you ever use belts of custom length or is everything COTS?

What’s the reason for the enclosed nature of the module? Also, what tread will you be using on this?

this is an incredible design! i am wondering how you got a hex on that 18t KHK bevel gear, did you machine it in-house?

and would you mind linking those bevel gears? i cant seem to find any similar ones on the KHK site…

Link for 18:45 1.25 modulus bevel gears from KHK

We are broaching the 3/8" hex in the 18T gear, and machining the round bore and bolt pattern in the 45T gear.

Enclosed means less things that can get broken from debris etc. We started doing this in the 2019 season with our drivetrain gearboxes and was very happy with the decision. We plan on trying to enclose more things like this going forward.

We are working on using the black SBR rough-top tread from McMaster.

Do you machine the bevel gear on your Omio CNC? If so, what are your feeds, speeds, and DOC?

They are purchased from KHK gears.


The bevel gears need to be finished once you purchase them to have a large bore diameter and the bolt pattern. I was wondering if they did the finishing in house.

We have not yet done this process, but we will be doing them in house. We will give you an update on how we did it once we have finished machining them.

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I was wondering how the swerve module has been progressing. Anything significant from what you had released earlier?

How did you connect the CTR mag encoder? Did you connect it to the spark max?

You can’t connect the encoder to the spark max they must be wired into the roborio. REV’s spark max does not support use of encoders with the neo motors.


Nice! That looks very snappy. Would you mind sharing how the encoder is wired, and how the controll loop works for the steering of the module?

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We used an encoder breakout board from ctr and wired it into the roborio then used a pid controller on the rio for each module.