Cable Disc brake caliper interference with Magic Pie 5 (front 700c)

[Mhawel]

Does anyone know what size disc is required for the brake caliper to clear the Magic Pie 5 front wheel motor? My Tektro IO front disc caliper that came with my bike interfere just slightly, so I'm wondering if I buy just a cable caliper and disc from Gary if it'll work... Which diameter is the question though...

Thanks!

Mike

[GM Canada]

First terminology, In North America we call them brake calipers. The rest of the world seems to call the brake activators.

First off you need to read the number printed on your brake disk. That is the size you need as brake disk mounts on the bike are located in a specific spot to accommodate the brake disk size they are designed to fit.

Calipers rubbing on the motor sometimes does happen. Regular bicycle brake calipers are not designed with hub motors in mind and most work but some do not. I have built quite a few bikes and have on some managed to add washers behind the disk moving it away from the motor and then adjusting the caliper to ride further away. I have also seen people use an angle grinder and grinding down the side of the caliper to clear the motor. It is not a pretty solution but could work and there is no loss trying it as you would likely be throwing out the original caliper anyway.

If you decide to get one of our narrower mechanical brake calipers it is and easy drop in replacement. But that being said, the ones I have are designed for 140mm rear disks and 160mm front. But this measurement only comes into effect if you use the mounting bracket that comes with the caliper. Most people don't need it as the brake disk mounts on the bike are designed in a way the mounting bracket that comes with the caliper is not needed. The direction of the mount determines if the mounting bracket is required. At 3:19 in this video https://youtu.be/ZmPko7w-chg?t=3m19s
 I address the two different ways disk brake calipers are mounted. So if you determine the mounting bracket is not needed then the mechanical caliper should fit any size disk. But in the wonderful world of "standards" there is always a possibility it may not, but it's unlikely. If you do decide to replace the caliper you may also want to consider getting the hydraulic brakes I have as they are really cool, easy to mount, never need to be adjusted and work very well.

Gary

[Mhawel]

Well, I was hoping that the GM calipers you sell existed simply to help when installs ran into interference issues, but I guess not, so I guess we can solve this by measuring the callipers you sell to see if they're in fact narrower than mine.

 I've looked already, and I can't find any specifications on other calipers from any manufacturers who make cheap mechanical disc brake callipers ( that are needed with my bike due to my integrated gear shifter and brake levers), with regards to offset from the mounting surface either...

Could you measure one for me gary?

Thanks!

[Mhawel]

Bump!

Gary, could you provide a rough measurement for the amount the golden motor brake activator protrudes towards the wheel from the mounting surface on the fork?

Thanks!

[GM Canada]

Well, I was hoping that the GM calipers you sell existed simply to help when installs ran into interference issues, but I guess not

Not sure why you would say that. I thought this was the exact reason we have them.

so I guess we can solve this by measuring the calipers you sell to see if they're in fact narrower than mine.

I don't think we need a measurement. It would seem impossible to move the brake disk closer to the motor, so that would also make it impossible to move the caliper closer to the motor than the disk allows

Could you measure one for me Gary?

Thanks!

I am quite under the weather. I maybe able to measure one over the weekend

Gary

[Mhawel]

Well, I was hoping that the GM calipers you sell existed simply to help when installs ran into interference issues, but I guess not

Not sure why you would say that. I thought this was the exact reason we have them.

Well who knows why you have them until they come here in the forums and ask, right? That's precisely the reason for my intial post, because there's no description of any value on the website, so there's no real way of knowing the intent behind the products design... Could be it's an old design from before the MP5 came out, and was made fir the Smart Pie... no way to know besides ask...

so I guess we can solve this by measuring the calipers you sell to see if they're in fact narrower than mine.

I don't think we need a measurement. It would seem impossible to move the brake disk closer to the motor, so that would also make it impossible to move the caliper closer to the motor than the disk allows

Obviously the disc can't get any closer to the motor, but if these are specifically for dealing with the clearance issues between the MP5 and the standard position of the discs on most\some bikes, then the description should be updated to reflect that. Then I wouldn't have had to come here and ask, and I probably would have already purchased one, and maybe even received it by now.

Could you measure one for me Gary?

Thanks!

I am quite under the weather. I maybe able to measure one over the weekend

Gary

Thanks!

[GM Canada]

The red makes you look angry. I hope you are not. I am just trying to help. I have sold a lot of these and no one ever asked me if they would work or complained they didn't fit. I did use a washer one time on a 902 kit to space the caliper over then realized shortly after I could have just adjusted it. I guess you are right about the description being vague but I just assumed people would realize they would work if I am selling them. I guess I could just put in a blanket statement that "these calipers work with all of our kits". On a lot of my products I do mention "this works with MP4 or MP5" for example. On Items that work for all I don't state that and maybe I should. The hydraulic ones would definitely work very easily with all kits as they are much more compact.

I was wondering about what measurements would be best to include and thought I should see what others dealers provide so my measurements would be complete. I did a google search of hydraulic disk brakes and mechanical disk brake measurements and cant find any one the internet that provides measurements. I imagine the key measurement is the body thickness of the caliper on the side from the where the disk fits in towards the motor.

Starting to feel a little better. Stupid spring colds! I should be up and around later today.

Gary

[Mhawel]

No, I'm not mad, lol. When I previewed the post I realized it was hard to see my reply's within the quote within a quote, without highlighting them somehow...

Well knowing that the calipers fit within the confines that the MP5 imposes is good to know. I'll place an order soon!

[Mhawel]

Caliper fits almost perfectly Gary! Just needs two small washers to space it out slightly from the mounting bracket it comes with because the inside of the caliper is rubbing on the edge of the disc when everything is tightened down.

Should have this thing running in no time at all after I come back from vacation! Looking forward to it!