Last night I was out on my 10 week old Giant TCX CX bike, all going well, good mix off on and off road, then when approaching a road junction on a steep downhill, both brake levers went straight to the handle bars and gave no purchase.

There was nothing, no stopping power. Fortunately a serious accident was avoided by luck. Has anyone else had this problem with mechanical disc brakes? I haven’t adjusted them since I got the bike, but its only been out abut 10 times and didn’t expect such a sudden failure.

Do you think they were wrongly set up to start with or just bad luck?

Also why are hydraulic disc brakes so expensive for road and CX bikes? Given what shimano offer for the mountain bike at good prices. Is it just supply and demand and in another year or so will the price have reduced significantly?

Sounds like the cables slipped through the retaining bolt

hmm. You aren’t very specific as to how the failure occurred.

If they are cable discs you need to adjust the pads to account for wear

both brake levers went straight to the handle bars and gave no purchase

all of a sudden having been fine minutes before?

need more info….

I had that on my tcx,brakes ok in normal use but when lots of pressure applied on a steep downhill they were terrible. All assembled correctly and adjusted properly,the problem was the extra effort disappeared into cable compression. I fitted compressionless cable and it was better but nothing like hydros.

My money is on the cable bolts not being tight. Never ever trust a bike shop to inspect a bike properly before you collect it.

Failure would be different. Is OP saying that both brakes failed as in the either something in the lever snapped or both calipers snapped.

OP learn to maintain your bike!

I’m guessing they still don’t work? Cable pulling through the pinch bolt would be my guess.

Oh and hydraulic brakes are expensive because its new technology and because the hydraulics and particularly reservoir fits in a shifter, some thing that isn’t required on an MTB. Mtb brakes don’t come with a shifter. They’ll come down in price though…

The pads need a quick fettle every now and then to account for wear. One of the main reasons I changed to hydraulics for my new bike. I had the shimanos on my TCX. I mistakenly adjusted the cable pull, felt fine initially then the back would not stop the wheel. The arm on the calipers was hitting the body before the pads had any effect

My money is on the cable bolts not being tight. Never ever trust a bike shop to inspect a bike properly before you collect it.

After 10 weeks both suddenly went together? I’m dubious.

Pad wear

Troll or bullshit.

I doubt it’d be pad wear.. Yes mech brakes need adjusting now and then as they wear but you’d notice the lever travel slowly increase over time.

My money is on damaged cable or the bolts that hold the cable were not tight.

Does anyone have a grudge against you?

Could be sabotage.. But with the bike being so new I’d still guess the bolts on the calipers that clamp the cable weren’t quite nipped up tight enough.

The brakes were becoming spongy while out on the ride, but giving sufficient power given the conditions. Then all of a sudden the brake levers went to the handlebars all of a sudden. And the there was no purchase.

When I stopped to check them, the wheels would spin with the brakes on full. I adjusted the cable adjuster slightly and this was enough to get some purchase, but after another 5 miles, there was another complete failure and I had to walk the downhills on the way home.

Yes they have had no maintenance, but they are only 10 weeks old and all my other road and mountain bike brakes don’t need adjusting that regularly!!

Sounds scary

Had this on an older MTB last weekend, if they are the type of mechanical brakes that have a fixed side and a single ‘piston’ that activates a moving pad….. The fixed pad side is adjusted using a kind of threaded barrel and this is locked in position using a grub screw through the calliper.

What had happened (investigated once we got home) is that the locking grub screw hadn’t been tightened and that meant that the barrel adjuster had gradually worked out so there was no contact possible = no brakes, front or rear, simultaneously.

Very strange that they would both degrade by the same amount and fail at the same, its very rare for front and back brakes to wear equally.

Does sound like pad wear if some adjustment brought them briefly back, did you check all the cables to make sure nothing had slipped?

Tell us what model the brakes are too, something with 2 moving pistons or 1 moving and a fixed side? have you checked the pad condition since?

but they are only 10 weeks old

weeks is a terrible measurement, is that 10 weeks = 200miles of road, or 10 weeks = 1000miles and offroad mud and grit?

Well the clamp screw may still be just loose enough to allow slight slippage.. Also the caliper mounts on mech brakes need to be set so both pads are as close as possible to the disks without rub or there will be excessive pad and consequently cable and lever travel.. I’d guess the shop didn’t set the brakes up at all before purchase.. They probably gave them a quick test without riding it, got some purchase and assumed all was ok.

You need to keep on top of the pad wear and wear adjustment (cable side and other side) or they can fail if the cam runs out of movement.

Typicall they need adjustment every few rides, takes seconds though.

More like 200 miles of 50% road (all very wet) and 50% off serious mud!

Had it with BB5’s that scared me quite a bit – downhill in traffic; being used to hydro’s where you don’t need to fiddle, but – soon learnt with cable on the cx you need to keep a feel on the lever travel and adjust frequently. Now with BB7’s that are better and easier to adjust, but it’s become a common check to do for me.

You need to learn how to adjust mech brakes.. But first port of call is remove pads and inspect, and check the cables and caliper mounts properly clamped.

Take it back to your dealer to have a look anyway. Has it been for a checkup since you bought it? Many dealers offer that as a free service.

Then look up the manual for your brakes and learn how to look after them.

We had a guy come into the shop last summer who’d managed to complete the Great Glen Way with no brakes because he had no idea how to adjust them. I mean it’s only your brakes, right? 🙄

Wasn’t there an issue with some make of cable brakes where you could pull the calliper arm over the top of the actuating lobe* which resulted in the harder you pulled the less braking action took place.
* May not be the correct technical term.

Some cables discs go “over cam”. Tektro Lyras are very good at this. I ditched mine years ago for that reason and a clubmate totally lost his brakes without warning a few weeks ago. It seems to involve the cable adjustment, especially if this is used to close the brakes up rather than do it properly. Having said that today my BB7s seemed to have no bite whereas yesterday they were great. Not enough miles to affect near new pads.

Sounds like pad wear to me. You need to move the pads closer to the rotor (not using the barrel adjuster but by using whatever mechanism your particular brake uses to move the pads)

TRP Spyres? I have these on my Giant TCX. Same thing on the rear brake. The brake levers pulls to a point, jams as if the brake is full on (it isn’t, it’s dragging on the disc, not gripping it) and then suddenly pulls back all the way to the bar. I’m guessing it’s a cable snagging in the outer. New cables and pads, front and rear tomorrow to fix it once and for all or the calipers are going in the bin and I’ll be getting BB7.

Doesn’t sound anything like pad wear to me! They suddenly failed, they didn’t get gradually worse.

I used to have this all the time with Hayes Sole’s. Same deal as with mechanical disc brakes: one moving pad and one fixed and you needed to adjust for pad wear.

All would appear fine, until all of a sudden neither brake would work.

In reality, what would be happening is the back would have worn to point it provided no useful activity unnoticed some time earlier. Only until the front went too would it become apparent there was a problem.

This would happen to a few of us with the same poor brakes / early superstar pads on muddy / wet rides, when braking was always a bit “loose”!

Spyre mechanical’s have both pistons moving. Mine are 100 miles old and have done it since new.

Sounds like cables slipping the anchors, not pad wear.

It’s easy to check which it is: just pull the levers and watch the caliper arm. If the arm moves immediately you pull on the levers, your problem is pad wear. If you can pull the levers partway back before the caliper arm moves, your problem is cable slip.

Pad wear on 10 weeks, nope.

Has OP checked the tightness of the bolts securing the cable? Just sounds like cable slipping through to me as said before

Come on OP, how much lever travel were you getting before it suddenly failed?

Didn’t TRP Spyres have a recall because of this fault about a year ago . The newer ones have been redesigned to prevent this from happening .

I am guessing the pads/cables had a lot of give and the bearings that generate the pressure (the ball bearing cam) ran past the end of the ramp.

What were the brakes?

Didn’t TRP Spyres have a recall because of this fault about a year ago . The newer ones have been redesigned to prevent this from happening .

I have a set of the newer ones and can confirm they do not do this anymore. I wore a set of the stock organic pads down to nowt on a wet ride before Christmas. The lever travel increased so I adjusted the cable but even with max cable pulled through they didn’t bite but still worked and didn’t fail totally as the older ones could.

I can sort of imagine the OPs situation – you could be riding round the woods using a bit of brake to scrub speed off. Hit the road and get up to much higher speeds and go to grab the brake and find they have no grab at all at higher speed.

Pad wear after 10 weeks? Yes, definitely possible.
I wore a set out on my cx bike within 2 weeks & a friend did the same, new & bedded in ( I bedded them in for him) & they wore to the backing plate in two races, so less than 2 hours.
Genuine pads & yes I do know how to bed them in properly-I do it for a living.