nickm77

Hi,

My new (to me) Cannondale ST500 touring bike has the side pull brakes and I am a little concerned about my braking power. My LBS sold me some larger pads that are supposed to give me more braking power but I still think it lacks what I need when heavily loaded going down a pass, etc. They told me that there is no way to put a better brake setup on my bike (I forget what it is called but think it is dual pivot or something along those lines) due to the way my frame is made or something like that. My current setup would be okay for simply commuting but I am concerned about touring.

Do you have any suggestions that I could try to increase my braking power. Or do you think that brake which are somewhat adequate for sport riding would be okay for touring in the mountains?

Here is the best Pic I have at the moment of my rear brakes. Sorry it isn't better. I'm on a trip so can't get a better one right now.

Thanks

Smooth James

I think if you are worried about braking power you could go with a larger brake pad and a more aggressive compound. Other than that I think you are stuck with the current braking system. Some people think that some systems are better than others, but I prefer V style brakes. Also remember that the front brakes do the majority of the work when stopping hard.

Nigeyy

Your LBS probably said that the brakes can't be replaced because they don't have canti post mounts (for cantilever or v-brakes) and are likely to be too high for the usual dual pivot brakes commonly supplied on road bikes (they aren't usually equipped on touring bikes since the profile is too low to allow for fenders to be fitted).

Some options or combination of options to consider to improve braking:

1. fit Koolstop salmon pads -I've found these pads are the best for braking
2. fit long reach dual pivot brakes -if you can. These brakes have longer arms than the usual dual pivot brake, so *might* fit.
3. fit different brake levers. You might be better off with brake levers that give you slightly more cable pull -even a millimeter or two can make a difference. Of course, this assumes that you have the hand strength.
4. keep your brakes well setup; keep pads and rims clean to maximize braking efficiency as well as cables in good condition with good cable runs.

cyccommute 

You need to find an old geezer mechanic. Young guys know absolutely nothin'

You need a long reach dual pivot brake. Tektro makes a couple of varieties. Universal Cycles carries them. Check with the Yellow Jersey also.

vik 

If nothing else works to your satisfaction you could replace the fork with something that has canti posts and run some v-brakes. As has been noted the front brake does virtually all your braking when you have to stop hard.

adun111

I've toured on old (80's) single pivots before with a 40 lb load. It's doable, just make sure things stay clean.

nickm77

Thanks guys! Actually my LBS said I could use a long reach brake but that it would be harder to use due to loss in leverage or something like that. So I hadn't considered it seriously. Is that true? Evidently you guys think they have better braking power or you wouldn't have mentioned them. I am certainly open to whatever works.

So how can I be sure they will fit on my bike? And would they get in the way of anything else (like fenders, rack, etc? And would it let me use larger tires? Right now I think I can only fit 1.25" tires on and that is pretty tight (they said I might have to deflate the tire to get it on and off???). I don't know because the bike is in the shop right now and I have not quite gotten around to putting larger tires on yet.

Nigeyy

Something I forgot to say from my original reply: your brakes may be perfectly adequate and don't need replacing -or if they don't feel so good, perhaps replacement brake pads will do the trick. Before you invest any of your hard earned money, test your brakes to see if they are good enough.

As to long reach dual pivot brakes -I'd say they are better than single pivot, if only because you'll have less centering difficulties. As to whether they will fit, the best I can say is "probably". It really depends on the frame and where the brake bridge is relative to the wheel. Also be aware in all likelihood the addition of long reach brakes will prevent you from putting fenders on (though the same could probably be said of your existing single pivot brakes anyway).

One thing to look out for with long reach brakes in quality; since the arms are longer, they should be good quality ones (Shimano Ultegra long reach are some) as any appreciable flex will not provide you with good brakes. If you're really concerned about braking, I like a previous posters suggestion that you could simply put on a new front fork and put cantis or v-brakes on it assuming you buy a fork with post mounts on it.

But.... let's not put the cart before the horse. I'm sure many, many people have toured on single pivot brakes with no problems as well. I think you should be really evaluating whether or not the brakes are adequate or not first -an investment in brake pads should be a very good cost effective move in ascertaining that (not to mention that if you don't like the results, you can still use the pads on some other brakes such as newer version cantis or v-brake if you get the cartridge type).

Smooth James

+1
I never thought about replacing the front fork! That’s a good idea.

LarDasse74

A lever with less cable pull (not more) is desirable to give more power. It's a moot point, though - I don't know if there is any significant difference between any currently available road brake levers.

Dual pivot long reach brakes (Tektro, available through Rivendell if nowhere else) will give you more power.

Nigeyy

No, I intended to put more cable pull; if the brake arms are flexy, having the ability to pull more can be better -but of course this does come at the expense of leverage (which is why I put the caveat of hand strength). Having a shorter cable pull can simply be swallowed up by the brake arm flex (certainly on the cheaper long reach brakes) and a longer cable pull can be considerably more effective.

There can definitely be significant differences in the road brake levers cable pulls -I can't remember precise measurements, but certainly Shimano STI levers have less cable pull than a Cane Creek SCR-5 -it's very noticeable. Likewise I had an old no name set of road levers that pulled slightly more than the SCR-5s. Unfortunately there isn't an easy way to find cable pull lengths (where's that web site when you need one!) for particular models unless you measure them yourself.

runair

I am also building up an ST500 frame as a loaded tourer. I hunted for a long time for the brake solution. In the end I installed a set of old Mafac centerpulls I had around. Work great, brake hard, fenders fit etc. These brakes do tend to squeal a bit but knowing how to adjust takes care of that. Don't expect the LBS to come up with this solution. It takes a geezer.

Scott

LarDasse74

This is only really applicable if the brakes and cables and levers are flexing so much that the levers are bottoming out before max hand force is applied. Otherwise, more cable tension (from higher leverage, less pull) levers will provide more stopping force.

Here is a super hi-tec info-picture I drew to show the difference between a flexible brake and non flexible brake. In both instances, the force pushing the spring (brake) is equal, and therefore the force pushing against the rim is equal, regardless of flex...

TheBrick

Brake plates are a possibility. From BMX stores

U brake



v brake


https://www.danscomp.com/489051.php

Nigeyy

Which can happen with the flex of the arms and the pad compression. I know it can -because it happened to me! From personal experience and observation, a longer cable pull (doesn't have to be much mind you and given the caveats I outlined) can improve the brake performance with flexy brake arms this situation is more likely to occur with long reach calipers.

I'm not sure I follow your diagram -does the spring represent a flexy brake arm? If that's the case I believe you are incorrect with your assumption that the force is equally applied to the rim in both diagrams -it depends on how much energy can be stored within the springs as they compress.

LarDasse74

No it doesn't.

Yes the spring and solid object are supposed to represent a flexible and a more rigid brake arm, respectively.

Every action has an equal and opposite reaction... If you apply a force of F to one side of the spring then there must be a force of equal magnitude - F - in the opposite direction acting in the other direction (the rim pushing back on the spring). Putting a spring between the applied force and the object does not change the amount of force the object recieves. Here is another drawing (force replaced by weight W)...



maybe the spring compresses and slows the rate that the force reaches the rim, but only by a tiny tiny fraction of a second (if at all - i am not sure of the micro-dynamic actions at play). A damped spring would affect the rate of loading, but there is no damping built into a solid metal brake arm.

If the OP is having trouble with the lever hitting the bar before applying max brake force (I don't think it is mentioned) then you are right - otherwise the brake is applying maximum power regardless of flex.

Nigeyy

Of course it's up to you, but personally I wouldn't want to place easily compressible springs in between my brake pads and brake arm and expect to have the same force applied to the rim......

LarDasse74

I never suggested that brakes are better when they flex more, or that the OP should find more flexible brakes - that would be rediculous... almost as rediculous as your suggestion to 'get longer pull levers and just squeeze them really hard.'

What I said is that you need maximum cable tension (ie less cable pull) to generate maximum braking force, regardless of how flexible your brakes are - which is why I included both a flexible and rigid model in my pictures.

The fact is, every action has an equal and opposite reaction (have you never heard this before?) - a flexible brake with a certain cable tension applied will push the pads against the rim with the same force as a more rigid similar brake with the same cable tension. Look at the second picture I posted (the ones with weights instead of lateral forces). If there is a 10 lb weight and a 1 lb spring, the ground underneath will feel 11 lbs of force, right? If there is a 10 lb weight and a 1 lb rigid bar, the ground will still feel 11 lbs, right?

Back in the days of centre-pull cantilever brakes, me and my colleagues did an experiment: set up a bike with Altus (cheap) canti brakes with low straddle cables (maximum leverage), and a bike with XTR cantilevers (very expensive) with high straddle cables (less leverage). Well, the flexy Altus brakes felt very very bad, but the bike stopped on a dime - you could lock up the front wheel and flip over the handlebars unintentionally. The XTR cantis felt great, but you had to really pull the lever hard just to get the back tire to skid... my point? Even cheap and flexy brakes will stop a bike when the cable is pulling them hard enough.

positron

vitriol aside, Lardasse is absolutely right.

To echo more helpful responses, tektro long reach (they make brake models that go from 37-49 and 49-74 if i remember correctly) are what you would want to buy if you need to replace your brakes- great quality for the price. But first, try salmon pads (I prefer scott mathauser over all others) and also, tighten your brake cables to the point where they are nearly rubbing the rims when disengaged, so you quickly reach full engagement upon brake application. Many people have made this work, so it is certainly possible.

LarDasse74

Who the hell do you think you are? First you dismiss my vitriol... (WTF is wrong with vitriol?) then you have the gall to suggest my responses weren't 'helpful?'

I was trying to let the guy know that he was off base and to counter some bad advice - possibly dangerously bad advice - with knowledge gained from years of experience. I only got a little peeved (vitriolic?) when the guy suggests the way he does it is better because he doesn't understand 8th grade mechanical concepts.

Also, I think the Tektro brakes are available from Rivendell (www.rivbike.com), probably accompanied by a wordy essay to make people believe their current bikes don't fit

Nigeyy

Jeez calm down!

I'll tell you what, I'll apologize for daring to question you (no big deal, hey, I feel secure enough). And I don't know what the heck I'm thinking, giving out a suggestion about something that has worked for me (a longer cable pull on flexy brakes). Clearly I must have been hallucinating and imagining it. No big deal -this is what boards are about -giving advice that works or not. It's up to the original poster as what he chooses to do or not to do.

Getting back to the topic -I liked the suggestion of the braking plates.

dcullen

Thats the ticket, I replaced mine with a Nashbar 1" Carbon Cyclocross Fork ( And don't ask why I never recommend racks that use a quick release front axle attachment). Cantis work great and there is enough adjustment and clearance to use both 700c or 27" wheels.
Most cyclocross forks are very close in distance from the axle center to the fork race so they wont change attitude of the bike, and they all have good tire/fender clearance and brake bosses. Most 700c road forks are a bit short tending to steepen the angles and tend to have minimal tire clearance.

But if I were doing it again I would use a 1" Surly Cross fork.. Chrome Moly with eyelets and canti/V bosses. https://www.bikemannetwork.com/biking/p/CXFK/FK0110
Its cheaper, it will clear 40mm tires and fenders and its steel. BUT its threadless so you now you need a new headset, spacers and stem and a brake cable hanger it you use canti's or V brake.

This is my ST400 with new fork

LarDasse74

Don't take it too personally. That's what the internet if for - belittling others for offering advice that may work or not.

I agree with the brake plates - if changing pads does not work a nice set of v-brakes (and a cable travel extender) would be the bee's knees! I did this on my city bike some time ago - mounted BMX U brakes on my 10 speed - to single speed - city bike - conversion and it worked like a charm (with massive amounts of filing and modifying to get it to fit).

positron

Sorry! all my posts are posted with a smile... and of course a bit of knowledge of physics is certainly helpful in all aspects of life from bicycles to midget tossing, but these days its not 8th grade but rather at college level when scary words like forces and newton etc. are brought up... sad state of affairs really.

Opie, let us know what you do in the end...

staehpj1

My suggestion is to put good pads on, be sure the brakes are adjusted properly and see how they work out before considering other options. Koolstop salmon pads would be one good option.