2011 Shimano XTR Trail Brake / Hope Rotor - Lack of power

matt_hillyard

Hey All,

I have 2011 Shimano XTR trail brakes (M985) and using Hope 160mm floating Rotors.

Apart from the first ride I've never been 110% happy with the performance and never been 110% confident with them.

I thought that the pads were contaminated so replaced them and cleaned the rotors with isopropyl alcohol and lightly rubbed them with the rough side of a sponge scourer to remove any oil/grit or dirt, I then had them professional bled and and I'm still not happy.

It cured the problem for about 2 weeks and then i started to lose braking power again.

Its almost like there is a bit of a slip between the discs and pads. I also have Hope V2's on my other bike and if your riding along at walking speed, if the brakes are on say half way they will grip you can feel the resistance, but with the XTR's they feel like there is little resistance and I have to grab a handful to get any reaction from them.

I have not had the brakes apart since the bleed and replacement of the pads so I have no idea whats causing this lack of 'braking grip'. The bike has barely moved as I've been out with a broken wrist so i know its not due to excessive wear.

Any ideas on the problem and also how this can be resolved??

Also I note that there are 2 types of Shimano olive and barb, one universal one and one designed for the M985. The M985 olive has a larger internal diameter for a greater flow of oil when the lever is pulled, would the small one cause a more spongy feel????


Cheers,

Matt

nicklouse

too small a pipe can reduce the operation of the brakes, the Hope Trial brakes could be improved with a bigger bore hose. so if the wrong barb has been used I would sort that out otherwise it will just be set up or poor rotors.

Chunkers1980

Aren't they designed to work with ice tech rotors?

matt_hillyard

Ok first thing is to check the LBS used the correct barb to ensure the correct fluid flow.

As far as I'm aware the rotors are compatible with the brakes as I checked this before I built the bike, and know other people running the same set up with far far better performance. The ICE tech rotors are only the center lock hubs and I'm running Pro 2's which are 6 bolt.

I have a feeling I may have to replace the rotors as if they are poor rotors or contaminated beyond repair and change pads for resin compound rather than the metal compound and see if i get better grip and stopping power.

matt_hillyard

I have just done a bit of googling and it seems that leaky M985 XTR hoses is more common than I thought and people have changed to Goodridge hoses with no problems afterwards.

Think I might need ANOTHER new set of pads and hoses.......Should i replace the rotors as well or will cleaning with isopropyl alcohol be enough as last time?

matt@theforce

matt_hillyard wrote:

Ok first thing is to check the LBS used the correct barb to ensure the correct fluid flow.

As far as I'm aware the rotors are compatible with the brakes as I checked this before I built the bike, and know other people running the same set up with far far better performance. The ICE tech rotors are only the center lock hubs and I'm running Pro 2's which are 6 bolt.

I have a feeling I may have to replace the rotors as if they are poor rotors or contaminated beyond repair and change pads for resin compound rather than the metal compound and see if i get better grip and stopping power.

Ice Tech rotors come in 6bolt as well as Centrelock. I've just received mine togo on my Sunringle hubs

matt_hillyard

The bike and brakes on their way back to maddison so will see what happens!