Tektro 203mm Brake Upgrade

IOUZIP

Active Member
Region
USA
City
Tampa
I have been working on this brake upgrade for some time. The stock 180mm dual piston brakes are good but I was ready for some better braking power. I was trying to get a set of the Tektro HD-E725 brakes but they have been out of stock for a few months. So I decided to get a the HD-M725 brake kit. I was not going to use the brake levers. I did used the hose and brake calipers. I kept the Star Union brake levers which have the motor cut out switch. Now I am still in the process of rebuilding the bike after some hard trail activity over the last year. 203mm front and rear rotors with Tektro 4 piston calipers. Started with front will add more pictures as it progresses.

Stock 2 piston Star Union calipers next to the Tektro 4 piston Orion 4P calipers.
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Tektro brake line fitting screwed right into the Star Union lever.
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When you bleed this brake system it was tricky. First used a syringe with Tektro mineral oil brake fluid and the right hose fitting in the caliper. Crack open the cover to the reservoir push the brake fluid up throught the caliper. Catch the overflow with a rag. Raise the caliper level to the lever height and remove the syringe from the caliper. Reinstall the screw in the caliper. You will need to burp the brake lever with little pulls on the lever. Once the air bubbles are gone reinstall the cover.

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IOUZIP

Active Member
Region
USA
City
Tampa
The second bike (wifes) I am sticking with the Star Union 2 piston calipers. That bike has the 100 mm fork I just installed today. Trying to finish the rebuilds tomorrow.

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Timpo

Well-Known Member
Have you considered getting a 248mm downhill rotor? 😁

 

fooferdoggie

Well-Known Member
Have you considered getting a 248mm downhill rotor? 😁

I cant imagine needing that much except for heat. going to the xt 4 piston man my braking is serious strong. Had a 203 on back but I have found no need for it. but then I am not going down
 

IOUZIP

Active Member
Region
USA
City
Tampa
Once I started trail riding the rear rotors warped. I have seen many other fat tire ebikes use 203mm and 4 piston setup on front and rear. I use alot of rear brake trail riding and warped a set of 180mm. My 2nd Juiced Ripcurrent S bike has the 203mm rotors but still use the stock 2 piston Star Union calipers.

203mm rotors and Tektro 4 piston calipers with stock Star Union brake levers.
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203mm rotors with Star Union calipers.
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Timpo

Well-Known Member
Once I started trail riding the rear rotors warped. I have seen many other fat tire ebikes use 203mm and 4 piston setup on front and rear. I use alot of rear brake trail riding and warped a set of 180mm. My 2nd Juiced Ripcurrent S bike has the 203mm rotors but still use the stock 2 piston Star Union calipers.

203mm rotors and Tektro 4 piston calipers with stock Star Union brake levers.
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203mm rotors with Star Union calipers.
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How are the front wheel during hard braking?

I found that on non-fat bike (CrossCurrent), the 203mm will mess up the alignment (angle?) of front rim because of very high torque being applied on one side during braking.
I always have to unlock the quick release, re-adjust it, and lock it again.
Does this happen to you?
I thinking I'm getting a thru axle when I have money.
 

fooferdoggie

Well-Known Member
if your warping rotors its time for better rotors or better cooling. we have ice-tech rotors on our tandem and man they are solid. we have rode the brakes fora couple of miles.
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Timpo

Well-Known Member
if your warping rotors its time for better rotors or better cooling. we have ice-tech rotors on our tandem and man they are solid. we have rode the brakes fora couple of miles.
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Those Shimano rotors do not have 6 bolt pattern.

I would recommend EBC or Galfer.

Galfer

EBC
 

fooferdoggie

Well-Known Member

IOUZIP

Active Member
Region
USA
City
Tampa
I have noticed the brakes are less touchy. When braking it feels more progressive less on/off and less likely to lockup. My butt tells me shorter braking distance when hard on the brakes now.

I did have to readjust the brake lever screws which I did not know I could do. This has allowed me to set the brake levers to the same distance. The rear is now at a different lever distance from the stock 2 piston setup. It's all good now.

When you think about the cost to replace 180mm vs 203mm plus an adapter bracket it really seems like a low cost upgrade for the stock 2 piston setup.

The additional cost of $180 for the 4 piston setup may not be in everyone's budget.
 

IOUZIP

Active Member
Region
USA
City
Tampa
I finally got around to testing the front brakes.

Stock Star Union brake levers, Star Union dual piston calipers and 203mm rotors the best stopping distance from 15mph was 16ft.

With the stock Star Union brake levers, Tektro 4P calipers and the with 203mm rotors the best stopping distance from 15mph was 14ft.

I did 4 full stops during testing on asphalt. Front shocks were unlocked. 15psi tire pressure.

Still working on the best rear brake setup for the next test.