Help with disc brakes on new bike

[Grumpyfatman]

Mechanical disks used to be hit and miss but I gather things have improved now.
My hydraulics are amazing but even they needed bedding in.
If you've tinkered with the settings and managed to get them gripping the rotor nicely but still find it lacking in grip then it's probably a simple case of needing to let the pads get nicely bedded in. Don't mess with the pads just get up some speed and brake sharply rinse and repeat until the pads are responding nicely.
I suspect it's unlikely that you'd get two pairs of pads that were contaminated but I suppose if they're from the same batch it's possible.
Have you done any background research on the disk brakes / rotors that you have installed? Is it possibly just a weaker brake set than you need?

 

[mythste]

get the pads replaced by the shop you got it from. I've got relatively "poor" disk brakes (by comparison) in the form of Shimanos R517 and when I changed the pads due to contamination it only took about 6 or 7 hard pulls to get them heated up and lock-able even at low speed. 1000 miles later theyre still going strong keeping my lard arse and fully loaded panniers coming to a stop smoothly and quickly!

 

[Kbrook]

Thanks all taking back to the shop is not an option as it was mail order. Going to change the pads first as that's relatively low cost, then if they are still crap will have another think.

 

[Milkfloat]

Sounds to me like classic contamination - could be over spray with WD-40 or similar - could be anything during the setup by the seller. Is it both front and back that have the issue?

 

[mythste]

Thanks all taking back to the shop is not an option as it was mail order. Going to change the pads first as that's relatively low cost, then if they are still crap will have another think.

Make sure you clean the disks off good and proper before you replace the pads - just in case!

 

[ColinJ]

As with all things bicycles, spending some money should cure the problem.

The hybrid cable operated hydraulic disc brakes are said to be excellent.

The reservoir is on top of the calliper, so no need to tinker with the brake lever/shifter - assuming you have drop bars.

The callipers should simply bolt on, but fit needs to be checked because clearance at the rear where the seat and chain stays meet is often tight.

http://www.bikeradar.com/gear/categ...hy-rd-cable-hydraulic-road-disc-brakes-47188/

I was having the same problem as Kbrook with the mechanical Promax Render R disk brakes on my CAADX. I could lock the rear wheel, but the front brake was nowhere near powerful enough. Coming down a 20% hill with my front brake lever pulled to the bars and still not slowing down enough convinced me to change the front brake!

I put a TRP Hy/Rd on and had a few teething problems with it but they turned out to be due to miscellaneous bolts not being tight enough, adjustment not being quite right, and the pads not being bedded in.

The Hy/Rd is working satisfactorily now. I have to pull the lever almost to the bars for full braking, but there is still just a bit of braking in reserve. I have been down the 20% descent a few times with the new brake and not had any problems. The brake is adequate rather than brilliant but I can live with that.

At less than full braking, the Hy/Rd is good. There is plenty of modulation when scrubbing off speed. I haven't used the bike in the rain so I am yet to see what the braking is like in wet conditions.

 

[Kbrook]

Thanks again all, part of the problem may well be that I expected too much from the new brakes. However it's not too much to expect a brake to able to lock a wheel. My shimano rim brakes, Ultegra and Sora are all capable of that.
I'm taking it up the Cross of Greets in the rain on Wednesday, some of you may know that, long climb, long descent. I will definately have bedded them in after that, if all goes wrong can someone collect me, I'll be implanted in the wall of the Hark to Bounty at Slaidburn.

 

[Kbrook]

I was having the same problem as Kbrook with the mechanical Promax Render R disk brakes on my CAADX. I could lock the rear wheel, but the front brake was nowhere near powerful enough. Coming down a 20% hill with my front brake lever pulled to the bars and still not slowing down enough convinced me to change the front brake!

I put a TRP Hy/Rd on and had a few teething problems with it but they turned out to be due to miscellaneous bolts not being tight enough, adjustment not being quite right, and the pads not being bedded in.

The Hy/Rd is working satisfactorily now. I have to pull the lever almost to the bars for full braking, but there is still just a bit of braking in reserve. I have been down the 20% descent a few times with the new brake and not had any problems. The brake is adequate rather than brilliant but I can live with that.

At less than full braking, the Hy/Rd is good. There is plenty of modulation when scrubbing off speed. I haven't used the bike in the rain so I am yet to see what the braking is like in wet conditions.

Colin, have you changed out both brakes or just the one?I'm contemplating changing just the one for now to the HY/RD to see how that performs.

 

[Wafer]

I'd take it to an LBS and get them to have a look. Absolutely confident they should be working better than that.
I've got the promax render r's on my bike and though I think they could do with upgrading, I can certainly lock the wheel up easily enough. Have adjusted them a few times over the last year when they've faded (general wear) and once done they bite well with out much lever pull.

TRP Spyre's are meant to be close to, if not the best cable operated road disc brakes so to have them performing so poorly suggests there is a setup problem rather than them just not being good brakes.

Take it in to reputable LBS, get it fixed, pay them £20, ride away happy...

 

[ColinJ]

Colin, have you changed out both brakes or just the one?I'm contemplating changing just the one for now to the HY/RD to see how that performs.

I just changed the front brake.

I am able to lock up the rear wheel with the old brake and you can't do much more than that.

It would be nice to have the Hy/Rds both front and back but they are quite expensive and I didn't want to spend another £80-odd just to have matching brakes.

If you only do one brake, do the front since most of your heavy braking should be done on that wheel.

It does sound odd though that your Spyres are performing so badly. I read some very good reviews of them. Maybe Wafer is right - if a bike shop could sort the problem out for £20-30 then you would save a significant amount of money.