Rear brake recall someone did it 14mm brake cylinder replacement?

[stingray]

Sure, but it's a 21.5% increase in cross-sectional area.

How so? From a 10% increase in diameter?

 

[2023R3GT]

Hi guys I have question, I received triumph recall on rear brake master cylinder replacement and some caliper spacers!! I never have problem with my rear brake and it’s working fine! Main question would you do free upgrade from old standard 12mm to new upgraded 14mm master cylinder for free by dealership or i should live it as is?? Kind not broken don’t fix? In my head 14 is bigger and better and will be advantage and maybe true couple years off trying to fix problem who has it, they finally accomplishes research and do have correct way to bleed the brake and make them work?? Any feedback who did and have good or positive feedback appreciate! English is not my first language so don’t judge strongly grammar!

The brake recall is a voluntary recall by the dealership and if done is free of charge. I had mine done around 10 months ago, needed a second manual bleed and brakes are working perfect ever since.

 

[Kiwicol]

How so? From a 10% increase in diameter?

Einar is spot on with the percentage difference. (21.518% larger) and conversely the 12.7mm version is 82.29% of the 14mm version. A = πr2 which gives you 1.5394 for the 14mm one & 1.2668 for the 12.7mm one. divide one into the other then x 100 to give you the percentage one is of the other.

However, percentages don't stop bikes, brake fluid does, namely a specific quantity of fluid being moved and able to exert 'x' pressure on the inside of the caliper to push out the pistons. If the stroke of the 14mm one is the same as the stroke of the 12.7mm one then you could expect the 14mm to be able to move more fluid (21.58% more) to the caliper than the 12.7mm one can, now whether this improves the issue of air trapped in the system? yeah dunno about that.

 

[20R3GT]

Update on 14mm master cylinder after all winter pulled bike out last Friday pedal still nice firm and short like after replacement!! Do never had issues with old cylinder eater!!

 

[TURBO200R4]

Update on 14mm master cylinder after all winter pulled bike out last Friday pedal still nice firm and short like after replacement!! Do never had issues with old cylinder eater!!

you are just lucky

 

[Einar]

Einar is spot on with the percentage difference. (21.518% larger) and conversely the 12.7mm version is 82.29% of the 14mm version. A = πr2 which gives you 1.5394 for the 14mm one & 1.2668 for the 12.7mm one. divide one into the other then x 100 to give you the percentage one is of the other.

However, percentages don't stop bikes, brake fluid does, namely a specific quantity of fluid being moved and able to exert 'x' pressure on the inside of the caliper to push out the pistons. If the stroke of the 14mm one is the same as the stroke of the 12.7mm one then you could expect the 14mm to be able to move more fluid (21.58% more) to the caliper than the 12.7mm one can, now whether this improves the issue of air trapped in the system? yeah dunno about that.

Exactly. The primary effects of the change (all else assumed to be equal):

Input travel is decreased ~20% for a given output travel ("firmer feel").
Output pressure is decreased ~20% for a given input force (weaker braking).