I read a lot about 4 pot caliper upgrades and everyone who installed them say that braking is improved. I also put 4 pot calipers that comes with TL1000S usd forks but I cannot see major difference. If I use TL master cylinder with 14 mm piston diameter instead of gsx 5/8" piston diameter, will it be better due to better pump/caliper piston ratio?
From what I have read, upgrading to a radial master cylinder is supposed to give a better percentage improvement in braking than changing the calipers. Whether that is true for the TL master cylinder I don't know, I don't know what type of master cylinder the TL one is.
TL has axial master cylinder just like gsx has but piston diameter is smaller, so it means that less force is needed on lever using TL's cylinder. :confused1:
smaller piston - smaller displacement of fluid, less braking force :confused1:
Smaller piston, more braking force :confused1:
Force depends on pressure, not on displacement :confused1:
Bigger piston to piston diameter ratio, more braking force.
Looking at all the responses - I think the answer is try it, as it sounds like it should improve braking. Just be careful with initial tests!
Ok, if you were to move 1 cc of brake fluid and 10 cc of brake fluid, which would move the pads more? 1cc or 10cc?
It doesn't matter how much fluid do you move, it matters how much pressure is created. Lets say brake pads need some amount of pressure to brake efficiently and both gsx and TL pump will create it. But you will need smaller force and more travel on lever that pushes smaller piston. It means gsx lever has to be pulled harder with less travel to create same pressure and force on brake pads.
Logic, isn't it? :confused1:
When the size of the master cylinder piston increases, the output pressure of the master cylinder decreases. A smaller master cylinder piston will exert more line pressure with the same amount of force (pedal ratio) than a master cylinder piston with a larger piston area.
But equally a smaller master cylinder piston increases lever movement as it has to move further to push enough fluid down to move the caliper pistons enough to apply the pressure to the pads.
It's all leverage, doesn't matter if it's hydraulic, cable or rod brakes.
exactly correct Hooli.
Quote from: Hooli on Thursday, 18 October 2018, 07:25 PM
But equally a smaller master cylinder piston increases lever movement as it has to move further to push enough fluid down to move the caliper pistons enough to apply the pressure to the pads.
It's all leverage, doesn't matter if it's hydraulic, cable or rod brakes.
Conclusion is that 4 piston calipers are not real benefit until proper master cylinder is used? :confused1:
:stir:
any idea of piston area, 4 pots compared to 6 pots?
Quote from: mlivkovich on Thursday, 18 October 2018, 07:50 PM
Quote from: Hooli on Thursday, 18 October 2018, 07:25 PM
But equally a smaller master cylinder piston increases lever movement as it has to move further to push enough fluid down to move the caliper pistons enough to apply the pressure to the pads.
It's all leverage, doesn't matter if it's hydraulic, cable or rod brakes.
Conclusion is that 4 piston calipers are not real benefit until proper master cylinder is used? :confused1:
:stir:
Depends on the area of the pistons.
Of course as they'll take smaller pads there is more chance of overheating them if used in a spirited manner with the same pad material.
Gsx
- master cyclinder diameter - 5/8" (15.875mm), area - 2 cm2
- caliper piston diameter - 27mm x 12 pcs, area - 68.67 cm2
- ratio 1/34.33
TL
- master cylinder diameter - 14 mm
- caliper piston diameter - 27mm x 4 pcs, area - 22.89 cm2
- 30mm x 4 pcs, area - 28.26 cm2
- ratio 1/33.24
My setup (gsx pump, TL calipers) ratio 1/25.57
If my calculations were correct, I found reason why is front brake lever harder after 4 pots conversion.
Sorry, but your calculations can't be correct as there are different sized pistons in the 14: Eight 27 mm pistons and four 24 mm pistons.
Thank you Andre, I missed that, hard to put measuring tool in caliper body. It means that gsx has even smaller caliper piston area,.
Easy one to miss :) I happend to have pistons and measuring thingy within reach.
BTW, I am happy with the 6-pods after rebuilding calipers and MC as well as switching the 16 year old rubber hoses to braided ones. One finger is enough to operate in most conditions. :grin:
Recheck your figures for the six pots. I don't recall the sizes but I'm sure two pistons are smaller than the other four.
Quote from: Hooli on Friday, 19 October 2018, 08:40 PM
Recheck your figures for the six pots. I don't recall the sizes but I'm sure two pistons are smaller than the other four.
I'm not so sure Andy - from memory the centre piston on each half of the caliper is larger than the outer 2 - so in any one caliper you will have 2 large (centre) pistons and 4 smaller (outer) pistons
It's the other way around 4 x 27 mm and 2 x 24 mm. Not relying on memory here but eyes. :cheers:
I think that there were more types of 6 pod calipers. Older one have same piston diameter and the new one have some piston smaller and some bigger.
I got a K2 and they are different sizes (as above)
Quote from: Andre on Saturday, 20 October 2018, 12:03 AM
I got a K2 and they are different sizes (as above)
I've got an early K2 (frame 240ish) and have various size pistons.
The part number never changed on gsx1400 brake calipers so they should all be the same across all years .
:cheers:
K2, 8 pots 27mm, 4 pots 24mm, thanks Andre and Hooli for the info
So.. has anyone changed their master cylinder yet and what were the results?
@mlivkovich. It's not a master cylinder upgrade I want , all I need to know is the diameter of the caliper pistons just in case I need to send the ones I got back. Thanks.
@mlivkovich , ignore my question I was looking at the wrong post. :facepalm:
@Tally if you read carefully this thread you will find piston diameters
:cheers:
Quote from: VladTepes on Monday, 26 October 2020, 05:01 PM
So.. has anyone changed their master cylinder yet and what were the results?
B-king master cylinder in my. Work perfect but for ideal - I had to change prake line from master cylinder to joint :onya:
Kozi, i talked about it lots, just never tried another. Other life things got in the way.