# Rear disc brake conversion **URL:** \ **Category:** GEM Forum\ **Created:** [June 2, 2022, 2:57pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360 "2022-06-02T14:57:05Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![bundcur](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@bundcur](https://community.electricforum.com/u/bundcur)\ **Post date:** [June 2, 2022, 2:57pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/1 "2022-06-02T14:57:05Z")
Well the day finally came and the rear drums finally bit the dust. I had an old this break kit laying around so it’s a little engineering and a little info from some other members here’s what I came up with. Sorry for this being just a teaser I will do a full write ![image](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/2X/4/497501e862e0ba7f50152ae40753b101426cd5c0.jpeg) ![image](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/2X/d/d81cef4834ad54e01f6139efba48ced07ce056a0.jpeg) up here in the next week or two. ---
**Author:** ![djgabriel2004](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/djgabriel2004/32/12304_2.png) [@djgabriel2004](https://community.electricforum.com/u/djgabriel2004)\ **Post date:** [June 2, 2022, 3:10pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/2 "2022-06-02T15:10:32Z")
Is there a way to adjust them? Having more Braking force in the rear end might be dangerous IMO ---
**Author:** ![bundcur](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@bundcur](https://community.electricforum.com/u/bundcur)\ **Post date:** [June 2, 2022, 4:10pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/3 "2022-06-02T16:10:43Z")
You are 100% correct in your initial concerns. I did take that into consideration and that is why I chose to use Acura Integra brake calipers. The pads for these calipers have a smaller surface area than what is on the front. In the shop whenever your takeoff of jam on the brakes the front would like up and scared for a distance than once a three-quarter slow down the backseat finally lock up. When I test drove it on the road and jammed on the brakes to lock the front up the box never locked up until you were almost to stop. Lastly we used an old race car trick, we put the car on jackstands and used a long prybar with a ft/lbs pounds scale/meter to the end of it to determine the break free point. Which was 61-67% of what the front took. You can install a bias dial to reduce rear brake pressure if needed right off the Master cylinder very easily. ---
**Author:** ![AssyRequired](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/assyrequired/32/7621_2.png) [@AssyRequired](https://community.electricforum.com/u/AssyRequired)\ **Post date:** [June 2, 2022, 4:30pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/4 "2022-06-02T16:30:51Z")
> The pads for these calipers have a smaller surface area than what is on the front I was thinking about this might be a decent way to tune a set of pads. If the rears locked up too easy you might be able to mill/grind off a bit of it to reduce the friction surface. It would wear faster, but if they are fairly thick they still might outlast the front. Maybe grind a hash x pattern so it doesn’t cock the pad/piston? ---
**Author:** ![bundcur](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@bundcur](https://community.electricforum.com/u/bundcur)\ **Post date:** [June 2, 2022, 5:04pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/5 "2022-06-02T17:04:39Z")
With the modifications I’ve done and having the high speed AC motor in my car any less wouldn’t be enough break. The rotors and the hubs are from the NEV accessories front disc brake kit. If you new exactly what vehicle the rotors you could fine tune it further. From everything that I have found the rotors have to be custom because of the size of the hole machined in the center of it. When I ran the numbers from the brake pads that came with the kit they were from a volkswagon. The front rotors for the Volkswagen part number did not match the rotor from the NEV disc brake kit. ---
**Author:** ![djgabriel2004](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/djgabriel2004/32/12304_2.png) [@djgabriel2004](https://community.electricforum.com/u/djgabriel2004)\ **Post date:** [June 2, 2022, 5:09pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/6 "2022-06-02T17:09:01Z")
Interesting, @GreenLantern was trying to upgrade his E2 and might be interested to follow this post ---
**Author:** ![JarJarJava](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/jarjarjava/32/15158_2.png) [@JarJarJava](https://community.electricforum.com/u/JarJarJava)\ **Post date:** [June 2, 2022, 5:16pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/7 "2022-06-02T17:16:35Z")
> [@bundcur](#): > > With the modifications I’ve done and having the high speed AC motor in my car any less wouldn’t be enough break. This is the 55+ mph GEM w/ the 9k rpm motor and 8.91 gears right? ---
**Author:** ![bundcur](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@bundcur](https://community.electricforum.com/u/bundcur)\ **Post date:** [June 2, 2022, 5:18pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/8 "2022-06-02T17:18:06Z")
Yes that is the one. Do you have a 6/1 gearbox laying around? Would like to see if it can brake 100mph. ![image](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/2X/6/6058a7e9bd1abc80fbeea82eb0a50ce73b06d542.jpeg) ---
**Author:** ![JarJarJava](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/jarjarjava/32/15158_2.png) [@JarJarJava](https://community.electricforum.com/u/JarJarJava)\ **Post date:** [June 2, 2022, 5:20pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/9 "2022-06-02T17:20:36Z")
![tenor](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/2X/6/611ade2e2b7c4631fc54d0746bbefa4e84d0c601.png) ---
**Author:** ![JarJarJava](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/jarjarjava/32/15158_2.png) [@JarJarJava](https://community.electricforum.com/u/JarJarJava)\ **Post date:** [June 2, 2022, 5:34pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/10 "2022-06-02T17:34:24Z")
> [@bundcur](#): > > Do you have a 6/1 gearbox laying around? Would like to see if it can brake 100mph. If I did, I would send it to you in a heartbeat. I would even kick in to bribe the safety & tech inspector at the local drag strip to let you make some passes. Watching a GEM e4 doing a burnout in the bleach pit would make it all worth it, ---
**Author:** ![David\_Illingworth](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/david_illingworth/32/2671_2.png) [@David\_Illingworth](https://community.electricforum.com/u/David_Illingworth)\ **Post date:** [June 2, 2022, 8:20pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/11 "2022-06-02T20:20:24Z")
Just install a Proportioning Valve. ---
**Author:** ![bundcur](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@bundcur](https://community.electricforum.com/u/bundcur)\ **Post date:** [June 2, 2022, 8:28pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/12 "2022-06-02T20:28:48Z")
Lol. For sure. I am in Missouri. At grudge match night at the dragstrip tech inspection consists of do you have a helmet and a seatbelt? If so you’re good to go. ---
**Author:** ![Laslonimne](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/laslonimne/32/514_2.png) [@Laslonimne](https://community.electricforum.com/u/Laslonimne)\ **Post date:** [June 3, 2022, 10:02pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/14 "2022-06-03T22:02:37Z")
> [@bundcur](#): > > Yes that is the one. Do you have a 6/1 gearbox laying around? Would like to see if it can brake 100mph. This should work: [EZGO Mid-1998-Up High Speed Gear Sets 4 Cycle Gas with Smaller Output Gear Bearing | GolfCarCatalog.com](https://www.golfcarcatalog.com/ezgo-mid-1998-up-high-speed-gear-sets-4-cycle-gas-with-smaller-output-gear-bearing.html) I believe this is the gear set I’m running. But check the numbers to be certain. ---
**Author:** ![Crawfish00](https://avatars.discourse-cdn.com/v4/letter/c/ce7236/32.png) [@Crawfish00](https://community.electricforum.com/u/Crawfish00)\ **Post date:** [June 9, 2022, 12:45am UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/15 "2022-06-09T00:45:04Z")
I’m in for this. Thank you!! This is something I’ve been wanting to do. ---
**Author:** ![jeff95519](https://avatars.discourse-cdn.com/v4/letter/j/ea666f/32.png) [@jeff95519](https://community.electricforum.com/u/jeff95519)\ **Post date:** [July 13, 2022, 6:10pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/16 "2022-07-13T18:10:47Z")
Here’s what you’ll need for the rear [JEGS 63022: Adjustable Proportioning Valve - JEGS High Performance](https://www.jegs.com/i/JEGS/555/63022/10002/-1?gclid=CjwKCAjw2rmWBhB4EiwAiJ0mtVD8Gc7epMGLeYOWwJlFcUQ2Oat8JfNEAYLgM9wWGU-R8t1ATbuNERoCiqsQAvD_BwE) ---
**Author:** ![Jonathan\_Cushing](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/jonathan_cushing/32/2083_2.png) [@Jonathan\_Cushing](https://community.electricforum.com/u/Jonathan_Cushing)\ **Post date:** [August 22, 2024, 3:42am UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/17 "2024-08-22T03:42:01Z")
@bundcur did you end up doing a write up on the brake parts used? How’s this holding up? ---
**Author:** ![bundcur](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@bundcur](https://community.electricforum.com/u/bundcur)\ **Post date:** [January 17, 2025, 6:23pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/18 "2025-01-17T18:23:14Z")
So sorry I have not replied to your question. Have been under the radar for a bit. I will get a write up posted for you. ---
**Author:** ![Jonathan\_Cushing](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/jonathan_cushing/32/2083_2.png) [@Jonathan\_Cushing](https://community.electricforum.com/u/Jonathan_Cushing)\ **Post date:** [February 19, 2025, 10:44pm UTC](https://community.electricforum.com/t/rear-disc-brake-conversion/24360/19 "2025-02-19T22:44:34Z")
Thank you. looking forward to it.