djb

rusted out brake lines with fluid loss? We once had a car where a line began to leak, although I wasnt in the car at the time so I dont know what it felt like. I know the driver was able to stop.The repair of brake lines was not particularly expensive.

GeoKrpan

Did you notice where Joe lives? Southern California.

You live in Finland but you argue like an American.

elcruxio

And had you read my post properly you would have noticed that I did point out that Shimano's work well in good conditions. But throwing out a blanket statement that they're excellent when they only are in a very narrow set of conditions is just plain wrong.

Gadgets4grls

Just thought I would chime in on this one.
I'm running TRP HY/RD cable actuated hydraulic brakes. Dual brake levers, brifter / TT, with compression brake cable housing, Yokozuna, and love them.
If I ever do have a catastrophic failure it's a 15 minute job to switch out to either another Hy/Rd or mechanical. This gets me 90+% of the benefits of hydraulics and no hassle with worrying about bleeding brake lines on the side of the road or having to worry about switching out levers/brifters.

I switched out for hand fatigue/pain reasons and am running 203 front / 180 rear on a Surly Disc Trucker 56cm 700C and haven't had a single issue.

As for the squeal issue. Easy trick when reinstalling a wheel. After the wheel is fully seated into the drop outs on both sides squeeze the brake lever, rubber band makes it easier, before clamping down the quick release. Assuming your rotor is true this help align the wheel so it wont rub.

Gadgets

DropBarFan

I thought about TRP HY/RD but then saw some posts about 'cable slop' so I considered TRP Hylex full-hydro but some folks claimed they were prone to excess lever travel also (plus the hydro hose can't readily be split for S&S couplers). Thus I figured to stay with BB7 for the while & try optimizing w/best setup/pads/rotors/prep. While replacing the rear cable housing I noticed that even with a full (& long) housing run, little of the lever travel was due to cable slop, which makes it sound like HY/RD might work well.

Anyway it's interesting to read about a Disc Trucker with HY/RD plus 'oversize' rotors, Surly page says only 160mm rotors?

elcruxio

I just realized that since I with my bike and gear qualify as an average tandem team weight wise I may need a rotor bigger than 160mm. Luckily I have all the hardware at hand to put in a 180. I'd probably put in a 203mm but I don't have a disc that size.

The 160mm has worked well enough until now but the 180 has a bit more heat capacity

Gadgets4grls

Hi DropBarFan,

I can't say positively why Surly went this route but my guess is for consistency.
I'm not sure a 180 rear would fit in anything smaller than a 56cm in 700C and don't know if it would fit at all on 56cm in 26".
So rather than having different sized rotors depending on frame / wheel size they went for a consistent 160.

If you're going to go the Hy/Rd route make sure to budget in compressionless housing as a necessity.
When I first installed them they bottomed out the brake levers without full engagement. I almost returned them but kept messing with them and they firmed up, never getting to great but finally to workable. Strange but what finally seems to really make a difference was over extending the pad piston without a rotor in between. I have the tool to push the pad apart when you do this by accident so it wasn't an issue. It was at that point that I replaced the housing and they actually became pretty good.

They do have more take up than my trp spyre did so it is still a bit of a trade off. On the other side though is a whole lot less hand fatigue and pain.

Well worth it in my case and after a short time don't even notice it anymore.

Gadgets

Gadgets4grls

Hi elcruxio,

I'm in the same boat, tandem and a half weight. Which is the reason I went through and upgraded. The other reason is wrist pain and weak hands.

The 203 in front is actually kind of funny looking but works great. I'm running the Surly nice rack in the front which helps protect the pie pan sized rotor. If I wasn't I would probably stick with the 180 just because the 203 is huge.

On the plus side I have no fear about being able to stop my freight liner.

Gadgets

fietsbob

Are you packing the bike in a carton, to go somewhere ? or just riding a really big loop to and from your front door?

discs get bent , more likely, when the wheels are out of the bike.. advantage rim brakes (?)



Took over someone else's built to order Bike-Friday (they didn't approve of the color)

recognized the advantage to the shimano splined centerlock hub/disc system over 6 bolt because of this..

have assembled several of other peoples bikes the ones that took off both wheels took a lot more time to put together too.


Bear that in mind , especially when you are the one putting the bike together , at airports, for example..

DropBarFan

Surly's page is a bit confusing & doesn't seem to differentiate between rotor specs for 559 vs 622 wheel. At any rate I feel that a larger spec rotor would be helpful. Fixed the rear BB7 & went for a test ride & they feel pretty good actually. Discs, whether mech or hyro, have initial lever travel but after that quite limited vs rim brakes that can continue to squash down so that one is perhaps unsure if lever will bottom out.

seeker333

You can fit 203mm diameter rotors into the frame and fork of any 700c wheeled Surly LHT or DT, and probably all of the 26" wheeled models except for the smallest frames (42,46cm) - and then you could still probably at least fit front 203s. I just measured my 56cm/700c DT - there is plenty of clearance for a 203 rotor. I no longer have a 26" LHT to measure for certainty, but I'm pretty sure the 26" forks will take 203s.

The problem with larger, more powerful disc brakes is they're more likely to loosen skewers possibly leading to an ejected/lost front wheel. Also applies to hydraulic discs. This is part of the reason MTBs have been abandoning QR hubs for several years now in favor of thru-axle hubs and forks and frames. Surly's 160mm spec is intended to prevent this problem.

Bicyclists should check skewers (quick or slow release) frequently if using disc brakes larger/more powerful than specified by manufacturer. Fortunately LHT/DT forks have "lawyer lips" to help prevent a lost front wheel.

romaneyoann

Hi, Nice discussion on Bike tour. You want to know about mechanical disc brake riders. But I have no idea about this. Last month I had gone for a one day trip to Bordeaux and there I took three hours to enjoy the bike tours of RusticVinesTours, which is the best way to see Bordeaux beach cruisers. Really by this tour we enjoy the biking experience. Thanks a lot.

gerryl

"...and will stop your bike." Do expensive brakes do something other than stop your bike?

Gadgets4grls

Hi seeker333,
I'm not saying you're wrong or right but I've taken that reasoning with a grain of salt in recent years and especially with the advent of "lawyer lips."

The issue when disc brakes where first coming out was a "softly" or "worn" installed QR skewer not having enough bite onto the fork which then could be "levered" out. Which was the actual problem not with a QR loosening.

If you want my honest opinion I think Surly went to 160 rotors not for lawyer reasons but for supply chain reasons. I tell my supplier I'm going to buy four times as many of a single product and want a better price and they're likely to give it. It also simplifies their stock as they only have to have one product for all Disc Truckers rather than 2 or more depending on frame size. I guessing but I'll bet that a 180 wont fit in 42cm Disc Trucker frame but a 160 will.


As for the reason mountain bikes have gone to through axles I'm of the opinion that this has more to do with frame/fork rigidity and lateral torque than wheel ejection. Got to remember that a mountain bike is subjected to a lot more "air time" and the resulting impacts than a loaded touring bike. The only time I'm going to get "air" is by accident rather than intent.

Just my opinion but I also grew up in a era where we didn't sue a manufacturer for our own stupidity with an honest expectation of cashing out on the deal, ie the USA "defective QR skewer" recall.

Gadgets

saddlesores

yes, they do indeed. when they break, they no longer brake,
becoming become merely ultra-hip, super-light, ueber-spensive
"brake"-the-bank bling-bling.

Joe Minton

elcruxio:

I do not doubt that you are truthful and accurate about your countrymen's troubles with Shimano hydraulic brakes.
Around here (Southern California) the inside of my freezer might qualify as a balmy summer’s day where you live ;o)

I've only been seriously back into bi-cycling for a little less that five years. One of the 'things' that bothered me about Shimano hydraulic disc brakes was their choice of petroleum ('mineral') oil as a working fluid.
Most everyone else (the world as a whole) uses DOT fluids (forgot the chemical name). One difference between these two types is viscosity index (VI), a measure of how the viscosity changes with temperature. DOT-type brake fluids have a very high VI which means that they retain their viscosity over a wide range of temperatures. Mineral oils’ VI is typically much lower and thickens more as temperature drops. Thick hydraulic fluid can be a problem, that’s why there isn’t any ;o)
I dropped my curiosity about this possible problem because, at the time, I was mostly interested in my personal concerns which did not include high latitude (brrr) locations. One of the thoughts that moderated my curiosity was the knowledge that it gets pretty cold in Northern Japan, Shimano’s home country. And they’re pretty good engineers. Perhaps I was mistaken to entirely trust that particular prejudice.

So – what’s to be done?
You probably cannot get away with changing to DOT-type brake fluids as they would probably ‘eat’ your Shimano’s rubber parts.
Perhaps there exists a compatible mineral oil with a higher VI than Shimano’s official offering? I don’t know, but it is worth looking into provided, of course, that VI is the basic problem. --- Interesting problem.

Joe

BTW: Synthetic oils naturally have a very much higher VI than traditional petroleum oils.

luker

I run hydros on my mountain bikes, and have most of the different varieties of mechanical discs on my tandem and touring bikes. They are all dependable, and they each have a failure mode or two. I love my shimano hydro brakes, but they have all sucked some air at one time or another and required bleeding. They give you some warning, though (getting spongey or requiring pump up at the lever before they will work), and if you ignore the warnings they can quit completely. The biggest advantage of hydraulics in my opinion is less force required at the lever, and thus better modulation.

That said, properly set up and adjusted mechanicals are completely adequate. Hy/Rd with 203s on the tandem, spyres on the touring bike, BB7s on patti's new marrakesh. Jagwire LEX compressionless housings everywhere on the mechanicals. A non approved tip for the TRP brakes...running the cable on the opposite side of the lock screw from the factory approved location firms up the braking a lot. That doesn't sound wise, but I haven't had any issues. Compressionless housings help so much that they should be required.

You can cook any brake...mechanicals are no exception. Search the tandem forum about melted calipers and rotors(!!!). Use good braking technique (don't drag your brakes).

It sounds like there is confusion about compressionless housings. There are several types: Jagwire, Yokozuna, Nokon are all common. I use Jagwire because I'm used to it, it works fine, and it's cheaper, sometimes. A famous bike mechanic warned against using compressionless housing a while ago, but modern compressionless housings are dependable, with one exception. Do not use 4mm housing in your brake system!!! That's the stuff Sheldon warned about, and his words are still true!

djb

Im learning here, is 4mm housing small or large (ie, I know nothing about housing diameters, I assume this is a diameter measurement?)

will remember your jagwire preference, thanks for all the info btw and your experience with the various models and brands.

Jaywalk3r

Larger rotors decrease the likelihood of wheel ejection compared to smaller rotors.

Per Jobst Brandt (Date: Thu, 27 Mar 2003 07:00:44 GMT): "The smaller the disk diameter, the greater the disengagement force for the same braking effect."

and

(Date: Thu, 27 Mar 2003 07:05:54 GMT) "The larger the disk, the lower the forces. In fact when the contact diameter of the disk pads reach that of the rim (as in rim brakes) braking forces are minimized."

luker

4mm is smaller, for derailleurs, and not reinforced to support the greater lateral loads required of braking. 5mm works okay for derailleur cabling, but it is a beeatch to bend.

luker

All of this is news to me...I haven't ever had a quick release loosen up (doesn't mean much, just never happened to me...)

I don't see a lot of increased leverage with larger rotors, but I do see an decrease in heat fade because of the larger mass acting as a heat sink. Ice Tech rotors help with heat fade even more...although there's a thread in tandems about someone who melted the inner aluminum core of an ice tech rotor. The older xt-m786 rotors had aluminum rotor arms and a solid steel braking surface...that is what I'm using for the tandem.

Jaywalk3r

I researched it quite a bit when I converted my Monocog 29er from rim brakes to disk brakes (up front). I ended up swapping my front fork to a Salsa CroMoto Grande (later replaced with a Fargo fork, identical except with rack mounting eyelets) for the Salsa fork's forward opening dropouts instead of the traditional downward opening dropouts. (Since then, other companies have adopted even more secure solutions.) I also opted for the largest front rotor "allowed" after contacting a Salsa rep.

350htrr

Theoretically, Yes, They should last for years and years, and years without any trouble, provide ultra stopping power, provide impressive modulation rain or shine, and... do it with no adjustment needed as the pads wear (hydraulics)... At least they did for me... For 16 years so far.

djb

thanks

Yan 

90% of my tours begin with a flight or train ride, where my bike is broken down and packed into a case. It's almost inconceivable that a disk rotor could survive such a trip without being bent out of alignment. As such I will probably never purchase a disk brake bike.