The TRP Parabox drop handlebar hydraulic brake converter debuted at the 2011 bike show in Taipei and quickly ran through the production process to start shipping late last year.
We just got our test unit in and immediately threw it on the scale and took lots of photos. In short order it’ll be on the MonsterCross project bike for testing and some first impressions. For now, check out the details…there are quite a few features features we hadn’t noticed on the early versions used on show bikes. Oh, and they’re already making running changes to get it ready for disc brake road bikes…
WHAT’S IN THE BOX?
You get the Parabox master cylinder converter, two 160mm rotors, the noodles for guiding the brake cable into the front of the box and necessary bolts for mounting everything. The calipers come with mount adapters for IS on both front and rear. Presumably, you could run smaller rotors if you’re bike’s set up for them.
There’s also an instruction manual. The system comes fully bled with hose lengths at 750mm front and 1,500mm rear. If you plan on shortening that, you’ll need TRP’s bleed kit and extra parts, along with a bottle of their TRP Mineral Oil Based Hydraulic Brake Fluid. If you don’t have that, TRP says Shimano’s bleed kit is a decent option, better than Avid’s for these brakes. Ideally, you’d use the kit made for the brand.
Without disassembling the unit, here are approximate part weights followed by actual system weight. Master cylinder converter comes in at 196g.
Front caliper at 131g and rear at 122g. No, those weights aren’t different just because the cable was resting differently, keep reading for an explanation.
System weight plus two twist ties comes in at 490g.
From left to right:
- IS F180/R160 adapter plus bolts: 27g
- IS F160/R140 adapter plus bolts: 23g
- Noodles: 15g
Rotors are 93g each and 105g with mounting bolts.
The master cylinder converter unit leads the brake cables in through the noodles at the front. The cables run through the silver bolts and are clamped down by small allen screws. Once tightened, small cable tension and pad adjustments can be made via allen keys on the plungers that push into the master cylinders. The noodles also have barrel adjusters to remove slack from the brake line. The black bolt in the middle/side of the body is the bleed port.
The master cylinder has front and rear specific sides designed to push different amounts of hydraulic fluid to each side. Shown above are the different rear (left) and front (right) calipers. Not only are the brake calipers different, but the front gets larger, longer brake pads, too. More details below. Here’s side by side visual comparisons:
Front – Rear
Front – Rear
Front – Rear
Why the different size calipers and plungers?
“We started this as a cyclocross project and we wanted to make sure the rear didn’t overpower the front,” said TRP’s marketing director Lance Larrabee. “So, on the Parabox master cylinder, the rear has a 9mm plunger and the front is 10mm. On the calipers, the front has a 21mm piston with larger pads and the rear has a 19mm piston. Besides balancing the power for ‘cross, we also wanted to make sure the rear caliper was small enough to fit on bikes that placed the disc brake mount on the chainstay rather than seatstay.”
For early 2012, they’ll make a running change to make the system more compatible with road bikes, too.
“We’re seeing more road applications coming, so we wanted to make the system more universal,” Larrabee said. “The new system will have a 21mm piston for both front and rear and a 10mm plunger for both sides. The Parabox master cylinder’s mount’s current stack height is 14mm but that’ll get shortened to just 5mm, and it’ll have a bit longer reach. We found that the larger pistons didn’t have any adverse affect on cyclocross bikes.”
Larrabee says the weight and price should be about the same. The current system uses calipers pulled from TRP’s existing mountain bike disc brake line. The new version will have all-new calipers designed specifically for road and cyclocross.
Retail on this system is $469.00. It’s available in Black (shown) and White, which includes white hoses as well.