Originally Posted by
DangerousDanR
merlinextraligh:
the V4 do indeed have a bigger piston than the E4, they use a larger pad than the E4, and because the V4 is also wider you can use the vented rotors. I started with a 203 mm Icetech rotor front and rear, but even after the switch to V4 calipers, the rear did distort from heat. The vented Hope rotor has not distorted. I consider my experiences with the E4 and the Icetech to have been my version of peeing on the electric fence. Trial, error, update, repeat. We survived without a crash, but we had one very close call with smoke pouring off the calipers and only minimal stopping power until they cooled.
Unfortunately, mineral oil has the nasty property of floating on top of water, so if any does happen to get into your system, the boiling point of the water is very low. If it is in the caliper, the brake is compromised. Yes, I change my DOT fluid on a regular basis. And the Castrol SRF has a dry boiling point of 320C and a wet equilibrium boiling point of 270C, which is pretty good. Here is SRAM's take on the subject:
https://sram.zendesk.com/hc/en-us/ar...r-mineral-oil-
I understand that with drop bars you are limited to the RX4 calipers. And I suspect that you are a lot lighter than Mrs. Dan and myself, and our full load of gear. If I wanted a drop bar setup, I suspect I would try to get a hold of the now discontinued Hope V-Twin master cylinder.
I know the V4’s have bigger pistons than the E4’s, as I stated.
The RX4’s have 2 bigger pistons than the E4’s.
what’s unclear between the now dated 2012 chart, and the link I posted is whether the current V4’s are any bigger than the RX4’s
As for mineral oil vs DOT Fluid, Shimano’s take is of course the opposite.
Not apples to apples, but I’ve seen a lot of cars boil DOT fluid on the track. Many Porsche clubs wont
let you on the track with
brake fluid over 3 months old.