Finally retired and building my project bike

[Trigger]

Very nice bike Trigger.
I’ve just read your project bike for £1000. Looks great too.  Interestingly when I converted this build to twin disc, I also removed material from the RH lower fork leg caliper mounting point.

It was the first time that i did a double disc and it was not just bolt the caliper arm on 
It is annoying that i had two squeaking disc's in stead of just one. The left hand side has now stopped squawking but, still a little squeak from the right side, if it carries on i will remove the second disc as, i preferer to brake in quite     

[McCabe-Thiele (Ted)]

Very nice bike Trigger.
I’ve just read your project bike for £1000. Looks great too.  Interestingly when I converted this build to twin disc, I also removed material from the RH lower fork leg caliper mounting point.

It was the first time that i did a double disc and it was not just bolt the caliper arm on 
It is annoying that i had two squeaking disc's in stead of just one. The left hand side has now stopped squawking but, still a little squeak from the right side, if it carries on i will remove the second disc as, i preferer to brake in quite     

TBH if feathering the front pads works as it often does in my experience with cars my suspicion would then be that it's a pad to disc alignment angle issue?

In cars it was linked to the move away from Asbestos pads - softer pads often cured the problem - cheaper so called high performance pads often made it much worse.

[gamma]

Mine is not yet on the road yet, so I will have to see

[Trigger]

Mine is not yet on the road yet, so I will have to see

750 never seemed to squeak, i have never had one squeal . It is always the 400, 500 and 550's.

[Sesman]

Mine is not yet on the road yet, so I will have to see

750 never seemed to squeak, i have never had one squeal . It is always the 400, 500 and 550's.

It either did or didn’t 🤔

Do we knowwhat causes it…Ted is convinced it’s the pad edge

[McCabe-Thiele (Ted)]

TBH most of my experience with disc pads is on cars over the last 58 years of working on my own vehicles (35/36 in all excluding motor cycles ) plus working in the motor trade full time for 5 years with my late father who was a RR/Bentley apprentice in the final years of WW2.   

My Dad started off working as a motor mechanic in the evenings post 1950 until he and his best mate at RR opened a Vauxhall Car Dealership initially in Mickleover moving to larger premises in Derby in around 1960.   After their dealership was bought out by a succession of car retailers he became a Main Board  Director of Bristol Street Motors International headed back in the day by the late Harry Cressman of BSG International.

My Dad supervised me fixing my first Honda a 250 Dream then guided me during my early Mini years - I was effectively raised as his apprentice from the age of 14 until I left Uni aged 23. I mention this as we both found squeaky brakes really annoying - feathering seemed to work on disc pads & also as an aside reduced brake grab on drum braked vehicles.

It was always my experience that the harder the brake pad the more regularly brake squeal occurred. I have always been a fan of "soft" brake pads as they used to reduce disc wear but produced a lot of brake dust - they did not last as long as "harder" pads and would fad sooner.

Once Asbestos was banned the issue seemed to become much more frequent as did disc brake run out due to warping discs - more so the early vented type. The move to sliding callipers has not always helped. Car manufacturers started to tell us it was a feature of the vehicles as they seemed to have no answer.

I have found feathering the disc pad not only works for many situations but it is now an integral part of modern car brake pad design. I am not claiming one size fits all - it has overwhelmingly worked for me.

 

[Trigger]

We are on about bikes with floating calipers Ted. It is a totally different from car calipers or any other type of fixed caliper 

[McCabe-Thiele (Ted)]

Yes I know the caliper design is different - more similar to a single piston design like many cars with sliding calipers only difference seems to be the length of the pivot point.

Cars have a noise generated from where the pad meets the disc. Even top brands like Merc struggle with brake noises since Asbestos went away - they came out with anti-squeal shime etc - none worked for all.

I did wonder if the SS type disc material was part of the problem.
It did occur to me if multi piston calipers were part of the reason Porsche and the like seem much less prone. Could some sort of surface heat hardening be the cause?

On my Jeep the caliper pistons are not metal - they are a plastic type of material - might be to stop them sticking in wet conditions.

[Trigger]

Same stainless material disc on a 750 and no squeal. The 750 piston does have a domed cap that goes in the piston so the pad is not sitting on a flat against the piston.

[Johnwebley]

You saying that, the 500 have a circular nylon washer between pad and piston

Sent from my SM-A546E using Tapatalk

[McCabe-Thiele (Ted)]

My 400 & 500 have the nylon type ring on the one static pad back.
I think Grahame is talking about the piston to pad contact being convex or concave.

[K2-K6]

An original 750 caliper sectioned schematic shows the fixed pad as shamferred and piston side pad with relief around periphery.

Dome on back of fixed pad, as Graham states a dome under the piston pad,  both to allow pad "float" to keep alignment flat with disc as caliper swings geometry with static pad wear.

Over the years different makes of pad have been supplied with shamferred edge or nil relief in my experience.

"Plastic" piston types in calipers are ordinarily Phenolic resin Ted, very high temperature resistant material with added advantage of low heat transfer to brake fluid given as advantage of use.

My experience is that you have to go unbelievably hot before that route into fluid would concern you, the whole caliper would be baking by then anyway.  I've run v-high temp pads in competion car, up where the disc glow yellow and the wheel bearing grease starts to run out as oil!  and without fluid boiling.

[McCabe-Thiele (Ted)]

I was using Plastic as a generic term in the broadest possible terms for anything from Nylon to Bakerlite sometimes derived from Petrochemicals.

Phenolic Resin nice to know the right handle to use - do any motorcycle manufactures use them in callipers? 

[gamma]

Battery fitted, no leaks as of yet
Making brackets to install front indicators, I shall fibreglass them to the inside of the fairing
Still looking for some high density foam to make a seat

[andy120t]

Have you looked at camping rollmats for foam?