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Promax Render-R Disc Brakes... Any Thoughts?

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Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Promax Render-R Disc Brakes... Any Thoughts?

Old 09-08-15, 01:50 PM
  #1  
OnyxTiger
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Promax Render-R Disc Brakes... Any Thoughts?

I just picked up a 2014 Fuji Sportif 1.3, which has the discs.

Some rubbing going on, but I'll let that slide for about 200 miles until break in readjustments.

But I was wondering... are there better brakes out there, or are these solid?

I previously had a 2015 Cannondale Quick CX 4 that I just sold, and the disc brakes on those were awesome. I had thumb shifters. The link says they are Cannondale Mechanical Disc 160/160 mm, but I never really paid attention to them because I didn't need to. They stopped on a dime. Really easy to modulate.

These Promax's are 160/140 mm. These ones originally started braking where the levers went all the way to the handlebar. The mechanic 'fixed' it, but the rear is stronger than the front, and there's a lot of roll, meaning it takes a lot of pressure in order to brake. His only suggestion was to check out some higher grade brakes. He has a mountain bike background, and suspects since discs are fairly new tech to the road world, that their brakes (coupled with Tiagra brifters) just aren't up to par.

Another forums says to upgrade to Ultegra shifters, since Tiagra is crap.

Should I consider going Avid BB7 discs, or upgrading shifters, or both?
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Old 09-08-15, 02:51 PM
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Start by just adjusting the pads properly. Mechanical discs are really simple to adjust, there's a screw to set the inner and outer pad. Basically just dial the pads in as far as they will go without rubbing. I'm running Shimano CX77 mechanicals, they've been 100% trouble free for 3500+ miles. No need to change the STIs or calipers (most likely.) If you're having constant problems with rubbing, check the rotors-- have you faded them at all? Overheating will warp them in short order, and then you'll get funky modulation and near-constant pad interference. IMO, the rotors are the most important part of the setup-- changing from the basic Tektro rotors on mine to Shimano ICE Tech took the braking from "pretty good" to "great."
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Old 09-09-15, 10:56 AM
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Originally Posted by OnyxTiger
I just picked up a 2014 Fuji Sportif 1.3, which has the discs.

Some rubbing going on, but I'll let that slide for about 200 miles until break in readjustments.

But I was wondering... are there better brakes out there, or are these solid?

I previously had a 2015 Cannondale Quick CX 4 that I just sold, and the disc brakes on those were awesome. I had thumb shifters. The link says they are Cannondale Mechanical Disc 160/160 mm, but I never really paid attention to them because I didn't need to. They stopped on a dime. Really easy to modulate.

These Promax's are 160/140 mm. These ones originally started braking where the levers went all the way to the handlebar. The mechanic 'fixed' it, but the rear is stronger than the front, and there's a lot of roll, meaning it takes a lot of pressure in order to brake. His only suggestion was to check out some higher grade brakes. He has a mountain bike background, and suspects since discs are fairly new tech to the road world, that their brakes (coupled with Tiagra brifters) just aren't up to par.

Another forums says to upgrade to Ultegra shifters, since Tiagra is crap.

Should I consider going Avid BB7 discs, or upgrading shifters, or both?
I have the same bike, and I'm not having any issues with my brakes, so they probably just need some adjustments. They did squeal a good bit until I got some miles on them. Now, they're pretty quiet.

I'm surprised that those other forums didn't tell you to upgrade to Dura-Ace. Tiagra now, is pretty much the same or better than Ultegra was about 10 years ago. And unless you're willing to upgrade your whole system, you'd have to go to a previous version of Ultegra that supports 10-spd. And then you'd lose a lot of the reason of going to modern 105/Ultegra. Keep you Tiagra (it's not crap) until parts start wearing out (other than the chain and rear cassette). Once they start wearing out, then you might look at upgrading to a higher groupset.

GH
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Old 09-09-15, 11:25 AM
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Originally Posted by DrIsotope
Start by just adjusting the pads properly. Mechanical discs are really simple to adjust, there's a screw to set the inner and outer pad. Basically just dial the pads in as far as they will go without rubbing. I'm running Shimano CX77 mechanicals, they've been 100% trouble free for 3500+ miles. No need to change the STIs or calipers (most likely.) If you're having constant problems with rubbing, check the rotors-- have you faded them at all? Overheating will warp them in short order, and then you'll get funky modulation and near-constant pad interference. IMO, the rotors are the most important part of the setup-- changing from the basic Tektro rotors on mine to Shimano ICE Tech took the braking from "pretty good" to "great."
Nice, that's good to know. I'm not sure what fading the rotors means. Sounds like changing rotors is fairly cheap, so I'll definitely consider that if the acting up comes around. Thanks.

Originally Posted by ColaJacket
I have the same bike, and I'm not having any issues with my brakes, so they probably just need some adjustments. They did squeal a good bit until I got some miles on them. Now, they're pretty quiet.

I'm surprised that those other forums didn't tell you to upgrade to Dura-Ace. Tiagra now, is pretty much the same or better than Ultegra was about 10 years ago. And unless you're willing to upgrade your whole system, you'd have to go to a previous version of Ultegra that supports 10-spd. And then you'd lose a lot of the reason of going to modern 105/Ultegra. Keep you Tiagra (it's not crap) until parts start wearing out (other than the chain and rear cassette). Once they start wearing out, then you might look at upgrading to a higher groupset.

GH
Thanks GH. I'd definitely like to keep with the current gruppo, I like how the gear changes aren't so huge like my other bike. Today, it's been silent after my morning commute.

Regarding your braking power, how good are they working for you? The modulation so far isn't as sensitive as my other bike with discs... are you able to trust these on a descent or if you need to slam in an emergency, or do they roll a bit?
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Old 09-09-15, 12:04 PM
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Originally Posted by OnyxTiger
Nice, that's good to know. I'm not sure what fading the rotors means. Sounds like changing rotors is fairly cheap, so I'll definitely consider that if the acting up comes around. Thanks.



Thanks GH. I'd definitely like to keep with the current gruppo, I like how the gear changes aren't so huge like my other bike. Today, it's been silent after my morning commute.

Regarding your braking power, how good are they working for you? The modulation so far isn't as sensitive as my other bike with discs... are you able to trust these on a descent or if you need to slam in an emergency, or do they roll a bit?
I've got a couple of big hills, and I'm sure if I pulled really hard on the front brakes, I could lock up the front wheel. The modulation is good for me.

I'm also sure that if I went to hydraulic disc brakes, that the stopping and modulation would be better. But since the bike has the disc brake mounts, I'm pretty sure the brakes could be upgraded to hydraulic.

GH
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Old 09-09-15, 10:22 PM
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Tried a bike with those brakes....... AWFUL!!! Would barely slow you down. Sure adjustment and bedding in would have helped some. Thing is, they made contact exactly where they were supposed to when the lever was applied. I eliminated that bike from further consideration because the Promax Render-R brakes were THAT BAD!

QT
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Old 02-28-16, 08:18 PM
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Thread bump.
Have these brakes. Will work great for running into the side of a car, dog, child, squirrels, etc.
Pull all you want to, better unclip and drag your feet. lol.
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Old 03-02-16, 03:55 PM
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Originally Posted by speedyb
Thread bump.
Have these brakes. Will work great for running into the side of a car, dog, child, squirrels, etc.
Pull all you want to, better unclip and drag your feet. lol.
This made me really lol. Thanks for that. Decided to use the bike as a commuter with platforms. Seems sneakers work really well with the brakes lol
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Old 03-23-19, 08:35 AM
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Promax Render-R disk brakes too soft

Hello,

Last year, a friend of mine bought a Genesis Croix de fer gravel bike brand new that came with Promax Render-R mechanical disk brakes.

It looks like Genesis no longers ships the CdF with those brakes, so it might be 2017 or 2018 end of stock.

She's been riding it for six months, and the braking is now a bit soft, ie. she has to pull more to actually stop. Readjusting the cable by about ~ 1cm/0,5 inches made no difference.

Any idea what else we could try to get them to brake hard like they used to?

Thank you.


--
Edit: Found it.

"Brake Pad Adjustment: The brake pads will wear during braking, which means the clearance between two pads will increase and brake feel will deteriorate. It might be necessary to adjust the clearance between the two pads by turning the pad adjuster B and the barrel adjusters on the caliper or the brake lever to get the original braking performance."
https://www.promaxcomponents.com/wp-c...ers-Manual.pdf

Last edited by Winfried; 03-23-19 at 09:21 AM.
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