My Experience with New Tires

[The Phoenix]

Like many on the forum I recently purchased new tires - in my case f/r Conti Road Attack 4. I had the tires delivered to a shop to mount the new tires and everything seemed to go well.
The next day I went for a ride and found the front and rear brakes to be rather soft when pressed. Among the things I checked was the brake fluid and found both reservoirs to be low. I found this to be rather curious as I am fairly consistent in checking basic things such as brake fluid level, air pressure, etc. According to the 2021 Manual when removing the wheels and calipers for tire change it's possible to leak fluid from the system and I am assuming that's what happened to me. So I just wanted to share what I learned - check brake fluid levels after tire changes or any work involving moving the calipers.

 

[670cc]

Like many on the forum I recently purchased new tires - in my case f/r Conti Road Attack 4. I had the tires delivered to a shop to mount the new tires and everything seemed to go well.
The next day I went for a ride and found the front and rear brakes to be rather soft when pressed. Among the things I checked was the brake fluid and found both reservoirs to be low. I found this to be rather curious as I am fairly consistent in checking basic things such as brake fluid level, air pressure, etc. According to the 2021 Manual when removing the wheels and calipers for tire change it's possible to leak fluid from the system and I am assuming that's what happened to me. So I just wanted to share what I learned - check brake fluid levels after tire changes or any work involving moving the calipers.

Over 45 years ago, I got my first bike with a hydraulic disk brake. Since the beginning, I have serviced all my motorcycles myself, including all wheel removal and installation. Never have I leaked a drop of brake fluid in wheel swap process. I don’t even see how a leak or reduction in brake fluid level could possibly happen during that process. I’ll need to check the manual you mentioned, as the comment makes no sense to me. Can you reference specifically what was written or where you found that?

The brakes could initially feel a little soft if the shop had pushed the pistons back in, but there is no reason they should have done that, and that feeling would totally clear after a couple brake activations. The brakes could also feel soft if the shop contaminated the disks with oil/grease/tire mounting lube while handling the wheels.

 

[Deleted member 1183]

Since the beginning, I have serviced all my motorcycles myself, including all wheel removal and installation. Never have I leaked a drop of brake fluid in wheel swap process.

Same for me.

 

[Egg on Leggs]

One possibility, as the original pads wore the level would go down. The rubber diaphragms will be pushed down into the fluid by air pressure which displaces the fluid, giving the impression that the level has not gone down. Putting it back together with the diaphragms back in their normal position gives a lower fluid level.

 

[The Phoenix]

Got back today after a number of days and checked my 2021 Service Manual and 2021 Owner's manual and I could not find a specific reference for changing tires and the potential for brake fluid leaks. Whether i was thinking about removing the wheel(s)/tires and moving the calipers and the possibility of moving the fluid tubing or doing something else which may have inadvertently leaked brake fluid I couldn't tell you at this point. That may teach me not to post at 4:13 am.
Nonetheless I apologize to any members who I may have misquoted when I shared my experience.