I replaced the pads on my mountain bike Hope discs a couple of weeks ago. Apart from that I haven't touched them in years. They just work. No worrying about lubricating and replacing cables, cables rusting, breaking, stretching, brake pads wearing etc. They just sit there maintenance free and just work. And they continue to work if a spoke breaks or the rim gets dented or buckled and through the worst conditions. If you ride off-road in gritstone areas you can easily get through two sets of rim brake pads in a single ride and I've demolished a couple of pairs over a weekend downhilling in the US.
Disadvantages of disc brakes?
- Thread starter Fnaar
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I replaced the pads on my mountain bike Hope discs a couple of weeks ago. Apart from that I haven't touched them in years. They just work. No worrying about lubricating and replacing cables, cables rusting, breaking, stretching, brake pads wearing etc. They just sit there maintenance free and just work. And they continue to work if a spoke breaks or the rim gets dented or buckled and through the worst conditions. If you ride off-road in gritstone areas you can easily get through two sets of rim brake pads in a single ride and I've demolished a couple of pairs over a weekend downhilling in the US.
Davidc
Guru
- Location
- Somerset UK
Interesting RL. certainly if I was looking for a MTB for offroad/ downhill/ XC use I'd buy one with hydraulic discs as original equipment.
With the prices I saw in a quick lookup I won't be fitting hydraulics as a modification at present. In days gone by, when I toured with heavy kit and/or went a lot faster than now I'd have considered it. I understand what you're saying and if I see lower prices might think about hydraulic rim brakes, if for no better reason than liking working on bikes!
At some stage I may get another new bike, and by then we may see changes in road technology so discs &/or hydraulics may be OEM fitted. This depends partly on UCI making new technologies legal in the events they control.
One change I'd like to see now would be road frames (Toring and Audax in particular) being equipped with the mountings for discs. The cheap bike I use as a utility bike came with standard V brakes but has mountings for discs if I choose to use them, that's what I'd like to see on real road bikes.
With the prices I saw in a quick lookup I won't be fitting hydraulics as a modification at present. In days gone by, when I toured with heavy kit and/or went a lot faster than now I'd have considered it. I understand what you're saying and if I see lower prices might think about hydraulic rim brakes, if for no better reason than liking working on bikes!
At some stage I may get another new bike, and by then we may see changes in road technology so discs &/or hydraulics may be OEM fitted. This depends partly on UCI making new technologies legal in the events they control.
One change I'd like to see now would be road frames (Toring and Audax in particular) being equipped with the mountings for discs. The cheap bike I use as a utility bike came with standard V brakes but has mountings for discs if I choose to use them, that's what I'd like to see on real road bikes.
Cross frames, yes, road frames unlikely. The forks need to be built quite a bit stronger to handle disc brakes so most manufacturers will stick with lightweight forks and no discs on road bikes.
ColinJ
Puzzle game procrastinator!
- Location
- Todmorden - Yorks/Lancs border
That is my experience too. I was trashing rims and brake blocks at an alarming rate on winter MTB rides up here in Calderdale so I made sure that I had disk brakes on my upgrade MTB. They have been totally reliable for 11 years and I am still riding on the same rims which have a couple of minor dents from hitting big rocks, but are otherwise good as new..
(I wore out a pair of brake blocks on a steep technical descent on my first MTB but had to carry on braking and destroyed the rim.)
byegad
Legendary Member
- Location
- NE England
I get it! In fact, I almost did end up with a permanent scar on one calf. I was amazed at how hot the rotor had got.
Well, maybe my descents are a lot longer and steeper than yours because I use the entire range of adjustment and can still end up with the brakes locked hard on until they cool!
I was searching for information on the problem a few minutes ago and one person suggested that bleeding a few drops of hydraulic fluid out of the system might be the answer. I don't mind adjusting the brakes on a descent but it is literally a showstopper when I run out of adjustment.
There is one particular local descent that I get to within 50 metres of the bottom of when the brakes start to overheat. If I'm careful, I can just get to the bottom and carry on.
One thing that has caught me out a few times is forgetting to adjust the brakes back the other way as they cool down. 10 minutes later, I go to brake and nothing happens!
I'm using cable operated Avid BB7s. You are talking about hydraulic lock, caused by brake fluid boiling.
So maybe you'd be better off with cable operated brakes. No hydraulic lock and easier to repair, what's to lose?
ColinJ
Puzzle game procrastinator!
- Location
- Todmorden - Yorks/Lancs border
The cost of a new set of brakes!
I reckon that slightly reducing the amount of hydraulic fluid in my brakes sounds like a viable plan. I'll try that in the New Year when I start cycling again.
byegad
Legendary Member
- Location
- NE England
No it won't. You'll boil the fluid just the same and the brakes will still lock on. That is the major disadvantage on hydraulic discs.
IF You are using metallic pads an organic set will reduce the heat transfer top the fluid, but the fundamental issue heat transfer to the fluid.
IF You are using metallic pads an organic set will reduce the heat transfer top the fluid, but the fundamental issue heat transfer to the fluid.
Crankarm
Guru
- Location
- Nr Cambridge
Brake fluid that does not boil? You would have to be doing some seriously hard braking on your bike to get brake fluid to boil. What fluid do downhill racers use or don't they use brakes ...................?
Nigeyy
Legendary Member
- Location
- Massachusetts, USA
Monty:
while I don't think I'd be as blunt
, I agree with your posts. All things equal (i.e. good quality examples of both) I do think one of the advantages of disc brakes is the ability to modulate and wet weather performance. After much experimentation, I find v-brake style brakes to be very digital on braking -but certainly as powerful as discs -though I do think discs outperform rim brakes in the wet -you get more consistent and predictable braking.
In fact, I've never found a really good setup with v-brake style brakes; I can't seem to find a brake lever with a lever shape I like plus a short enough pull to give the kind of modulation I like. On the other hand, I love some cantis I have for the exact opposite reason -the modulation and power they provide is outstanding -and is only let down in the wet weather. Just my opinion, but I certainly don't share the love of v-brake styles brakes (I really don't want my wheels to lock easily, thanks!). Anyway, the reason I love my discs is down to 3 basic facts: i. they are more than powerful enough, ii. they modulate excellently, and iii. they provide -so far -the best wet weather performance I've had on a bike brake. Having said that, are they that much better? To be honest, no. If I was building a touring bike again and was on a budget, discs wouldn't be a necessity that's for sure. However, if budget wasn't a big deal, I'd definitely get them! To summarize: I just don't think discs offer the best bang for the buck. If you have the money, I'd say get them, otherwise don't worry if you can't.
Actually, this leads on to a big belief of mine -when we talk about brakes, I think we should be talking about the whole of the system including the brake levers as they are also essential to the essence of the brake performance. It's truly amazing how much of a different feel you get to a brake simply by having a different cable pull of literally 3 mm. I've heard people slag off cantis in the belief they are inherently a bad brake design -it may be some people have some poor quality flexible cantis, but overall I can't help but think oftentimes it's the poor or mismatched brake lever that is more the cause of the issue (assuming they are set up appropriately). In fact, I really wish brake lever manufacturers would post their cable pulls (it really would seem to something that would be very handy to know!).
Oops, I've digressed from the original question..... yeah, as other people have posted, it's down to personal choice. I think it's safe to say none of the common brake system designs out there are bad.
while I don't think I'd be as blunt
, I agree with your posts. All things equal (i.e. good quality examples of both) I do think one of the advantages of disc brakes is the ability to modulate and wet weather performance. After much experimentation, I find v-brake style brakes to be very digital on braking -but certainly as powerful as discs -though I do think discs outperform rim brakes in the wet -you get more consistent and predictable braking.In fact, I've never found a really good setup with v-brake style brakes; I can't seem to find a brake lever with a lever shape I like plus a short enough pull to give the kind of modulation I like. On the other hand, I love some cantis I have for the exact opposite reason -the modulation and power they provide is outstanding -and is only let down in the wet weather. Just my opinion, but I certainly don't share the love of v-brake styles brakes (I really don't want my wheels to lock easily, thanks!). Anyway, the reason I love my discs is down to 3 basic facts: i. they are more than powerful enough, ii. they modulate excellently, and iii. they provide -so far -the best wet weather performance I've had on a bike brake. Having said that, are they that much better? To be honest, no. If I was building a touring bike again and was on a budget, discs wouldn't be a necessity that's for sure. However, if budget wasn't a big deal, I'd definitely get them! To summarize: I just don't think discs offer the best bang for the buck. If you have the money, I'd say get them, otherwise don't worry if you can't.
Actually, this leads on to a big belief of mine -when we talk about brakes, I think we should be talking about the whole of the system including the brake levers as they are also essential to the essence of the brake performance. It's truly amazing how much of a different feel you get to a brake simply by having a different cable pull of literally 3 mm. I've heard people slag off cantis in the belief they are inherently a bad brake design -it may be some people have some poor quality flexible cantis, but overall I can't help but think oftentimes it's the poor or mismatched brake lever that is more the cause of the issue (assuming they are set up appropriately). In fact, I really wish brake lever manufacturers would post their cable pulls (it really would seem to something that would be very handy to know!).
Oops, I've digressed from the original question..... yeah, as other people have posted, it's down to personal choice. I think it's safe to say none of the common brake system designs out there are bad.
what a crock of crap
more crap
...but if it helps you justify your purchase
stewie griffin
Über Member
- Location
- Quahog
I don't have a disc equipped bike & I'm neither for nor against discs, but surely a disc equipped bike stresses the wheels more than a rim braked bike?
Discs must have the same effect as the rear wheels drive "hub twist" in the opposite direction & at a much much greater force (can you accelerate in the same distance you can stop?) so I expect spokes have to be stronger (& wheels relatively heavier), the front forks beefier as well as the weight of calipers, etc.
Rim brakes don't twist the hub in the rim, the braking forces on a rim braked wheel are similar to just putting more weight on the bike, but no twisting forces.
I can understand the advantages on a MTB where rims are subjected to more dirt & can be ground down quickly, & how nice it must be to be able to run bucked wheels without issue.
What I don't get is where any of this is useful on a road bike, where over & over again simplicity has proven to be the best bet for trouble free cheap cycling. So MTB yes, road bike no.
But I'm happy to have my opinion changed
Discs must have the same effect as the rear wheels drive "hub twist" in the opposite direction & at a much much greater force (can you accelerate in the same distance you can stop?) so I expect spokes have to be stronger (& wheels relatively heavier), the front forks beefier as well as the weight of calipers, etc.
Rim brakes don't twist the hub in the rim, the braking forces on a rim braked wheel are similar to just putting more weight on the bike, but no twisting forces.
I can understand the advantages on a MTB where rims are subjected to more dirt & can be ground down quickly, & how nice it must be to be able to run bucked wheels without issue.
What I don't get is where any of this is useful on a road bike, where over & over again simplicity has proven to be the best bet for trouble free cheap cycling. So MTB yes, road bike no.
But I'm happy to have my opinion changed
Nigeyy
Legendary Member
- Location
- Massachusetts, USA
Yes, they do. But I think the real question to ask is "does this really make a difference?"
I haven't had a disc wheel fail yet. I really think this is along the lines of a disc wheel being inherently weaker, or disc brakes being more complex and hence more likely to suffer a mechanical breakdown. Theoretically it is, but practically a good quality well built disc wheel or good quality disc brake will be fine.
Admittedly anecdotal -but as I said,I haven't suffered a disc wheel failure yet after many, many miles (as well as my friends who ride with disc wheels) and I've actually had more trouble with traditional rim brakes (tension spring breaking) than on my disc brakes. Course, YMMV.
I haven't had a disc wheel fail yet. I really think this is along the lines of a disc wheel being inherently weaker, or disc brakes being more complex and hence more likely to suffer a mechanical breakdown. Theoretically it is, but practically a good quality well built disc wheel or good quality disc brake will be fine.
Admittedly anecdotal -but as I said,I haven't suffered a disc wheel failure yet after many, many miles (as well as my friends who ride with disc wheels) and I've actually had more trouble with traditional rim brakes (tension spring breaking) than on my disc brakes. Course, YMMV.
I don't have a disc equipped bike & I'm neither for nor against discs, but surely a disc equipped bike stresses the wheels more than a rim braked bike?
But I'm happy to have my opinion changed
byegad
Legendary Member
- Location
- NE England
Or more likely you will boil moisture absorbed by the fluid.
Any locking on in a hydraulic system that self releases when cooled down is due to this.
ColinJ
Puzzle game procrastinator!
- Location
- Todmorden - Yorks/Lancs border
The fluid can expand without actually boiling!
As mentioned in previous posts above, the Hope C2s have controls to compensate for this fluid expansion. My problem is that I get to the end of the range of control after about 250-300 vertical metres of descent. That happens to be towards the top end of what I have to descend round here so enough extra control to back off the brakes for another 100 metres worth and I'd be happy. Removing a small amount of hydraulic fluid might do the trick. I'll try it when I get back on the MTB next Spring.
There are obvious advantages in terms of braking quality. The principal disadvantages on a tourer are that they are more vulnerable, and that they require a stiffer and thus less comfortable fork. My personal preference on a loaded tourer is for Magura hydraulic rim brakes. But if budget is a concern, I think nothing beats a pair of Deore v brakes, particularly if used with Koolstop Salmon pads.
Willem
Willem
I've done some pretty serious hard braking on long runs on my brakes and have never had a fluid boiling problem. I've even blued the discs a few times they got that hot.
What ColinJ is talking about is something completely different. Hope make closed and open hydraulic brake systems. With the closed ones there is no compensation for the expansion and contraction of the braking fluid temperature with volume so as the brakes heat up the fluid expands and eventually locks the brakes on with the lever released if it gets hot enough. There are adjustment caps on top of the brake levers to allow you to adjust for this on the fly and for ambient temperature changes.
All that has happened is CJ has set his brakes up so they are in the right position in ambient with the adjusters fully out so he cannot back them off further. He just needs to reset it with the adjusters turned in a few turns so that now when the brakes heat up he has a few turns of adjustment left to compensate.
