Author Topic: Trek 520 poor brakes  (Read 13193 times)

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Offline PeteJack

Trek 520 poor brakes
« on: November 11, 2013, 03:24:46 pm »
The brakes on my Trek 520 that I love dearly are not very good. Originally the front brake was very noisy and didn't work at all well. Braking was something I had to plan especially loaded up. I got some relief from the noise by using Jagwire pads and cured the noise problem completely by replacing the Single Digit SD-5 front brake with a Single Digit Ultimate at great expense (5X the cost). The new front brake is does work a bit better but hard braking with my hands on the hoods is still difficult, I have to reach round to the drops to do that. Is there anything in the way of different levers, cables etc. Can anyone suggest a way of improving braking from the hoods? The cable outers and levers are the originals that came with the bike in 2005.

Offline DaveB

Re: Trek 520 poor brakes
« Reply #1 on: November 11, 2013, 04:45:59 pm »
Replacing the cables and housing with lined housing and coated cables should help.  Replacing the brake pads with Kool Stop Salmon pads is probably the biggest improvement you can make.  Finally, be sure your rims are clean and free of dirt and grit.   

Offline John Nelson

Re: Trek 520 poor brakes
« Reply #2 on: November 11, 2013, 07:31:22 pm »
Do everything Dave said, and then make sure your brakes are adjusted properly. Make sure they hit the rims in the right spot, and that they are toed in, and that they have the correct spacing to the rims. Also make sure your rims are not worn out and concave. If you're still having trouble, then have your local bike shop do the adjustments.

Properly adjusted and with good pads, cables and housing, they should work fine.

Offline TokyoNose

Re: Trek 520 poor brakes
« Reply #3 on: November 11, 2013, 10:03:25 pm »
Please don't be insulted by the simplicity of this question, but...

Are you sure that the brake levers are compatible with linear pull (V-type) brakes?  You mentioned that the levers are the originals that came with the bike.  Was the bike originally equipped with cantilever brakes?  Most road-style levers will not pull enough cable to effectively actuate a linear pull brake.

Offline John Nelson

Re: Trek 520 poor brakes
« Reply #4 on: November 11, 2013, 10:07:02 pm »
All the Trek 520s in quite a few years have come standard with linear pull brakes, so this should be okay unless he's changed the levers.

Offline DaveB

Re: Trek 520 poor brakes
« Reply #5 on: November 12, 2013, 09:55:59 am »
Please don't be insulted by the simplicity of this question, but...

Are you sure that the brake levers are compatible with linear pull (V-type) brakes?  You mentioned that the levers are the originals that came with the bike.  Was the bike originally equipped with cantilever brakes?  Most road-style levers will not pull enough cable to effectively actuate a linear pull brake.
I thought of that too but, if the bike came with "road" (short pull) levers, the problem would be too much power and the need to have the pads very close to the rim since they have greater leverage but less cable pull than V-brake compatible levers. 

Offline paddleboy17

Re: Trek 520 poor brakes
« Reply #6 on: November 12, 2013, 12:43:44 pm »
Make sure that the rim is true and free of surface imperfections.

A "travel agent" is used to allow non linear pull brake levers work with linear pull (aka V) breaks.  This might give you some mechanical advantage.  They are cheap, so it is worth trying.

Lastly, this sounds like a job, albeit an expensive job, for hydraulic brakes.  Yes they are expensive, but they do know how to clamp.  ::)
Danno

Offline Old Guy New Hobby

Re: Trek 520 poor brakes
« Reply #7 on: November 12, 2013, 03:55:32 pm »
I agree with John Nelson, but be informed that the biggest advantage to cool stop salmon pads is when it's raining. When it's dry, the pads aren't that much better than others. The only time I had a problem with my 520 brakes was one time in the rain before I switched to the cool stop salmon pads. There may be something else going on with your bike.

Offline Pat Lamb

Re: Trek 520 poor brakes
« Reply #8 on: November 12, 2013, 04:55:53 pm »
Kool Stop salmon pads work as well as anything else I've tried when wet.  However, as far as I'm concerned, their biggest advantage is that they don't pick up grit or small bits of gravel.  That means the KS pads aren't acting like lathe tools to cut your rim down when you brake, and you don't have to listen to the grinding noise while braking.  Nothing else comes close, IME.

Offline DaveB

Re: Trek 520 poor brakes
« Reply #9 on: November 12, 2013, 05:42:36 pm »
A "travel agent" is used to allow non linear pull brake levers work with linear pull (aka V) brakes.  This might give you some mechanical advantage.  They are cheap, so it is worth trying.
Travel Agents would make the situation worse since they increase cable travel at the expense of leverage.  If the OP has V-brakes with non-V levers, as I mentioned above, his problem would be too much power and not enough lever travel.  That's exactly the opposite of what he is describing.   

Offline bogiesan

Re: Trek 520 poor brakes
« Reply #10 on: November 12, 2013, 09:43:01 pm »
If replacing the brake mechanism did not improve the situation, the fault cannot be in the brakes. That leaves the cable, the jacket, the ferules, the levers and any other pieces/parts that are between the hands and the rim. You have eliminated one element. Now you start with a set of binary tests, changing out only one item at a time. 

On my recumbent, the front brake is almost worthless. But I have a very nice unit from Paul. The rear is where all the action is and it's just a regular ol' Avid linear brake. The cable is quite long, tandem-length, so I'm careful about the jacketing and ferule placements. And I use pink or salmon pads. Most of the time. And I keep the rims very clean.

I play go. I use Macintosh. Of course I ride a recumbent

Offline mbattisti

Re: Trek 520 poor brakes
« Reply #11 on: November 12, 2013, 11:47:16 pm »
When you're applying the brakes, how far will the brake levers continue to move after the pads initially contact the wheel rim?

Offline PeteJack

Re: Trek 520 poor brakes
« Reply #12 on: November 13, 2013, 05:46:20 pm »
Thanks everybody for your suggestions. The levers are the ones that came with the bike along with the SD-5 Vee brakes. The Ultimate does give better braking but is still not fantastic e.g. on an unloaded bike I couldn't launch myself over the bars if I tried. I'm using the Avid pads that came with the brake.
Quote
When you're applying the brakes, how far will the brake levers continue to move after the pads initially contact the wheel rim?
You may be on to something there. They do feel kind of squishy after the pad hits the rim, in fact it's hard to tell when the pads have hit the rim. With my Roubaix cantis there's a definite stop in lever movement when the pads meet the rim. Presumably I should be getting the same with the Trek's V brake? Perhaps after 40,000 miles the levers and outer cables are worn out. Recommendations for cables and levers please?

I don't think it's rim wear. The wheel has only 5k on it and the braking was pretty poor when the wheel was new with new pads.

Offline John Nelson

Re: Trek 520 poor brakes
« Reply #13 on: November 13, 2013, 05:56:29 pm »
Recommendations for cables and levers please?
Cables: new ones; new housing too. Almost any ones will do.
Levers: the ones you have now.

Start there and see if that fixes it. No need to do more until you do the basics.

Offline PeteJack

Re: Trek 520 poor brakes
« Reply #14 on: November 13, 2013, 06:19:25 pm »
Thanks John. I may as well replace the levers and here's why. My LBS has a sort of co-op arrangement where you you can use his stands and tools. One day I was redoing the tape on my bars and while I was at it installing new inner brake cables, the levers had a small noodle like an inch long version of the noodle on the V brake. I didn't know what purpose it served as the brake seemed to function just fine without it. The assistant in the shop (who now works in a distillery) didn't know what it did either so I left it out. When I came to put a new inner with my new brake I found its purpose. I could not get the new inner into the cable from the front of the lever without unwrapping the bar tape! As I don't even know the brand of the existing levers (there's no name on them) rather than try to find another noodle thingy I think I'll get new levers and new outer cables