# Rubber bumper need?

**URL:** <https://community.electricforum.com/t/rubber-bumper-need/17372>\
**Category:** GEM Forum\
**Created:** [October 25, 2019, 2:38pm UTC](https://community.electricforum.com/t/rubber-bumper-need/17372 "2019-10-25T14:38:17Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Inwo](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inwo/32/1067_2.png) [@Inwo](https://community.electricforum.com/u/Inwo)\
**Post date:** [October 25, 2019, 2:38pm UTC](https://community.electricforum.com/t/rubber-bumper-need/17372/1 "2019-10-25T14:38:17Z")

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@Old_Houseboater  
I don’t understand what the bumper does. When swapping to an ac induction motor, do I need a bumper? Is it a motor thing?  
I did not use a bumper in my hot-rod golf cart. No noise or issues.  
Guess I can look at a parts list for the new ac Gems.

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**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\
**Post date:** [October 25, 2019, 3:27pm UTC](https://community.electricforum.com/t/rubber-bumper-need/17372/2 "2019-10-25T15:27:43Z")

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New GEMs dont use them, Classic GEM’s do. They take up the slack and keep a preload on motor/shaft interface to reduce noise when off throttle.

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**Author:** ![Inwo](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inwo/32/1067_2.png) [@Inwo](https://community.electricforum.com/u/Inwo)\
**Post date:** [October 25, 2019, 3:50pm UTC](https://community.electricforum.com/t/rubber-bumper-need/17372/3 "2019-10-25T15:50:07Z")

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Thanks, I’ll have to let @Troyin909 know.  
Any chance too much preload can cause over heating of bearings or motor?

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**Author:** ![RS\_E6](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/rs_e6/32/12308_2.png) [@RS\_E6](https://community.electricforum.com/u/RS_E6)\
**Post date:** [October 25, 2019, 4:49pm UTC](https://community.electricforum.com/t/rubber-bumper-need/17372/4 "2019-10-25T16:49:04Z")

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Yeah, I recall seeing posts for others that added a dime behind the bumper and it was too much resulting in those symptoms.

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**Author:** ![Troyin909](https://avatars.discourse-cdn.com/v4/letter/t/57b2e6/32.png) [@Troyin909](https://community.electricforum.com/u/Troyin909)\
**Post date:** [October 25, 2019, 6:07pm UTC](https://community.electricforum.com/t/rubber-bumper-need/17372/5 "2019-10-25T18:07:51Z")

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I have the small rubber bumper in my motor spline. I don’t seem to have any issue with it But let me know what you guys think.

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**Author:** ![Inwo](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inwo/32/1067_2.png) [@Inwo](https://community.electricforum.com/u/Inwo)\
**Post date:** [October 25, 2019, 6:31pm UTC](https://community.electricforum.com/t/rubber-bumper-need/17372/6 "2019-10-25T18:31:15Z")

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Probably nothing. I’m looking for your over heating issue.  
Motenergy just answered an email, telling me the motor was certified to propel a small car at 35mph. He also asked for more information, so I will forward to you and Richard.