Adjusting hydraulic disc brakes on Tern GSD e-cargo bike?

[ishaqmir]

Hi

Just bought a brand new Tern GSD e cargo bike and I have just done about 10 miles on it local. I’ve noticed when spinning the front and back wheels that the discs are rubbing on the pads, especially front wheel.

Called the retailer/service shop and they advised it can happen due to transit and they are happy to take a look and sort it for free. Problem is, they are 3 hours drive from me (was the only shop in UK to have the bike in stock!!) so that’s not really an option.

Any advice on how to sort it myself, especially grateful for any owners who have experience with that or similar bike.

It has the Magura MT5 hydraulic disc brakes. The bike arrived very well packaged with no real damage to the card board etc. Rides lovely, but obviously using excess energy with brakes rubbing, and will cause premature wear.

 

[raleighnut]

Loosen the mounting bolts then pull hard on the brake lever whilst retightening them, that should align the calipers.

 

[Globalti]

If the brake is just rubbing and not actually slowing you down, don't worry because the pads will soon wear away from the rotor. If actually braking and the rotor getting warm, try forcing the pads apart with a screwdriver blade. You might have to open the bleed nipple to allow a couple of drops of fluid out.

 

[ishaqmir]

If the brake is just rubbing and not actually slowing you down, don't worry because the pads will soon wear away from the rotor. If actually braking and the rotor getting warm, try forcing the pads apart with a screwdriver blade. You might have to open the bleed nipple to allow a couple of drops of fluid out.

thanks for the replies, yes that did come to mind. I watched a YouTube video on how to adjust hydraulic callipers but when I shone a light at the front calliper and did a full rotation, I could not see any significant space between pads and disc during the entire rotation, as though the pads are too fat/too far out?
I really don’t want to mess around with the hydraulic fluid, is it easy to adjust so pads go back into calliper? May be just use your screw driver technique? Or just ride it and let them break in? It’s not slowing me down at all... only noticed it when I spun the front wheel by chance while it was on the kick stand.

 

[Globalti]

So if the brake isn't binding, just ride and stop worrying. In cars the pad actually rests on the disc and causes a very small amount of drag but in bikes you can't have that so the seals are designed to distort under hydraulic pressure then return to their square section, pulling the pads back a tiny distance off the rotor. After a while the pads wear and then the pistons will begin to creep microscopically through the seals to take up the wear.

 

[chriswoody]

Has the bike got quick release skewers or through axle?

I discovered on my Kona that the way you close the quick release skewers can have quite a pronounced effect on the position of the disc rotors and wether the pads rub. The knack I've developed to stop the pads rubbing is to the grasp the top of the wheel and part of the chainstay with one hand, then carefully eyeballing the back of the caliper I close the skewer, moving the wheel microscopic amounts to keep the disc rotor perfectly centred between the pads.

I hadn't really appreciated before owning a disc braked bike that the quick release could be the cause of pad rub as well. Another good reason for through axles.

 

[Globalti]

Yes I'm on my first through-axle bike now, the new Roubaix, and I'm hugely impressed by them. Okay they're not instant like a QR but amateurs don't need that. They more than compensate by the strength and stiffness they give the frame and forks. I just love the engineering.

 

[Elybazza61]

I wouldn't mess with bleeding or anything as Maguras can be a pain to bleed.

As above posters mentioned First port of call would be check wheel alignment and if that's ok but the pads still rub loosen bolts, pull lever and then re-tighten while holding the lever.

 

[ishaqmir]

Thanks for the replies, it’s definitely through axles, I tried loosening the quick release but front wheel was still solid in place as expected.

I’ll loosen the bolts on calliper and re position as advised above and then just bed them in and review it after a good few miles...