Dockhead

Hi, Forum!

I mostly live onboard a sailing yacht, and I migrate back and forth between the UK and Finland every year. I have mostly given up land life and no longer have a car, so the folding bicycle is my primary ground transportation. In Scandinavia, and also on the Isle of Wight, the two places I spend most of my time, there are extensive bike roads and trails, so much better than cycling in the U.S. in my youth.

I have a Dahon Jetstream EX, my first folding bike, which far exceeded my expectations (I ordered it from Germany sight unseen) by riding very much like a normal road bike, and in some ways even better because of the full suspension. I have Shimano clip-in pedals for it which I use with Shimano cleat system, which is also a far cry from the toe clips and unwalkable cleated shoes of my youth. Knocking out 50 miles in an afternoon is no problem -- although I'm now in my 50's and far less fit than I was back in my cycling days. I had not quite imagined that this would be even possible on a folding bike. But the frame is stiff, the geometry is good, and the gears are splendid. I hardly notice the small wheels except when going downhill.

The only place where the Jetstream falls down is riding downhill, where it feels unstable, and the brakes suck. The instability is inherent to small wheels I think, so I'm going to just live with that, but I really don't think I will tolerate the brakes. The German A suspension on my bike has bosses for disk brake calipers, and indeed the very next year of this bike, the brakes were changed to SRAM Avid Juicy hydraulic disk brakes.

I have been looking at SRAM and Shimano disk brakes, which I guess are kind of massive overkill on a folding bike used on the road, but hey. I've got my eye on the SRAM Guide R's, which have recently gone out of production, but which are still sold, and at a discount. They are selling them in sets of two for 160 pounds (about $200) on Fleabay, without the rotors, which seems reasonable to me.

The only problem I'm having is -- how to choose the rotors? They come in different sizes. I can't find any data from Dahon, and don't quite know how to measure it.

Can anyone help?

Also any other tips in general about hydraulic brakes on folders?

bargainguy

All the Dahons I've seen with discs use a 160mm rotor.

Now as to whether hydraulic disc brakes on a folder is a good idea, I dunno. I'm perfectly fine with mechanical disc brakes on any bike, as the modulation is superb compared to rim brakes. It helps to keep the rotor meticulously clean (I like alcohol for cleaning the surface) and free of grit, as that will wear down your pads substantially.

But on a folder with hydraulics - esp. one you'll be folding and unfolding often - there is an increased risk of damaging the lines (kinks, bends, leaks, etc.) compared to a rigid bike. Not to mention the general increase in maintenance, flushing & bleeding the lines regularly, etc.

So does the switch from mechanical disc to hydraulic disc on a folder make sense? It's more maintenance than I would want to put up with, and also a little more finicky in practice, so I wouldn't go this route personally. I like to keep things simple. But that's just me.

tds101 

I'd recommend avid bb7's. Excellent mechanical disc brakes. Hydraulic brakes are overkill IMO.

Pinigis 

We offer models with both hydraulic and mechanical disc brakes. There is very little difference in the modulation of the brakes, and no difference in their stopping power, but the hydraulic brakes just look a bit cleaner and more tidy without the cable sticking out.

Dockhead

Thanks for the great feedback!!

I am surprised to get the recommendation for cable disk brakes. I don't have any personal experience, so I'm open minded. But I always heard that the feel is much, much worse, compared to hydraulic, due to the friction in the cables. Is that not true??

I really crave a hard, distinct contact point, good feel and modulation, and plenty of power. Remember this is not a 3 speed Brompton-type putt-putt urban folder, but a 27 speed aluminum frame full suspension bike which I ride with cleats at normal road bike speeds. I'm open minded about the cable brakes -- anything will be better than what I have now -- but will they feel as good?

I may be carrying a lot of stuff (like groceries back to the boat), and might some day be pulling a trailer -- so stopping power is important too.

Thanks again for all the advice.

BTW, still interested in the question of how to find out the right diameter of rotor.

fietsbob

It has a lot to do with your mechanical aptitude and willingness to pay, You able to do engine overhauls at sea, on your boat?

remember it has to be folded repeatedly, Explain how would you cope with a broken hose to your rear brake?


happy medium may be the all the hydraulics at the disc caliper TRP HyRd, it uses a cable all the way to the wheel.

and a short pull lever... they aim at builders of road bikes , so there you would use a cantilever type brake lever rather than a V type..


But I have mountain BB7 discs, 160 rotors, on my 406 wheel bike friday,, have to be careful with the front one ,

it can work too well and stop the bike out from underneath me..





......

fietsbob

Thing about mechanical discs, the pad wear adjuster is You...

easiest : Pails clampers,.. big metal knobs ,

BB7 the inner knob [I usually have to use a Torx screwdrivers.]though its large and plastic, outer one is plastic ..

TRP Spyre/Spyke mechanical, both pads move to the disc, a wee 3mm wrench adjusts those ..




....

ThorUSA

good hydraulics are better...
good mchanicals are better than bad hydraulics
get Avid bb7 and you should be fine ..... unless you have kinked cables or salt inside the cables..lol
than Hydros will shine again


for added stopping power you might find adapter which let u use larger rotors ... like 200 front and 160 rear .. :-)

Dockhead

Are you saying that hydraulic brakes require more frequent repair?

I don't think mechanical aptitude is a problem. I have different hydraulic systems on my boat, vastly more complex than bicycle hydraulic brakes, including hydraulic autopilot with 24 ton ram, which I maintain and repair myself, yes, sometimes unfortunately at sea. And I've lived with hydraulic brakes for decades on cars and motorcycles. Broken hose is a pretty straightforward problem -- replace it, refill the reservoir, bleed, go. Might be some special quirks for such tiny systems, but small hydraulic systems are not rocket science.


But the question remains -- do hydraulic brakes FEEL a lot better than cable ones? I would be surprised if they don't, no?

fietsbob

planning to buy 2 or 3 spares to have backups?


With die drawn, Slicker surface, Stainless cables and the teflon lined housing ,
now offered low compression with a kevlar braided sheath..

the mechanical types can put you face down on the pavement pretty fast..




visit a few bike shops and try some out.. ** IDK what the Moorage fee per foot is in Portland Oregon.

a good days motor- sailing up the Columbia from her, but its a bike nuts town with several hundred different bike shops..

they have the money for fancy things there.

** OK its on a different ocean as am I ..

Magura of Germany* makes really good Hydraulic disk brakes for mountain bikes... at a range of price points..

You have a Water Tight Deck Locker to stow the bike in ? Or does it fit in the sail locker?

* own a bike with their hydraulic rim brakes, on a bike (that does not fold).. for 8 years..



....

Joe Remi

I've ridden several mechanical systems and one hydraulic. Hydraulic feels miles better and will be better sealed from water and salt and stuff. Spend the money, be happy.

tds101 

IMO, if you have the skills (and you definitely do,...), go for hydraulic!!! I was shooting for simplicity,...but having a closed system in a marine environment is a huge advantage.

Dockhead

They blow that often? Really?

I keep a good half a ton of spare parts of various types on board, and have a full workshop on board including power tools and even a drill press, so in principle that's not a problem at all, in any case. I keep spare tires, tubes, chains, cables, and other stuff for the bike already, and a full set of tools.

Still, I am curious -- are hydraulic brakes on bikes really that troublesome? I never had so much trouble with them on other types of vehicles.



Bike storage is a horrendous problem on sailboats, even a big one like mine (54 feet and 32 registered tons).

I keep mine in a spare cabin when I don't have crew or guests on board; otherwise in the lazarette, which is a locker reached through the deck at the stern end of the boat. It doesn't get wet in the laz, but the air is damp and salty, so maintenance is a challenge.

I'm planning to replace all the chrome-plated bolts with stainless or titanium this year, and I think about replacing some other parts which start to rust.

Dockhead

Thanks!

Dockhead

What do you (and others) think about the SRAM Guide-R brakes?

fietsbob

Gone to the SRAM website and look it up yet?


have a rubber gasket sealed hatch or a variation of an inflatable life raft container made up to be air tight
to keep out the saline mists.

lots of bolts on components are not general hardware , but were manufactured in house, only in steel with chrome plate.






///

Dockhead

Yes, I've been trawling the SRAM website and reading what reviews I could find. But I was specifically interested in whether people have used them on folding bikes -- all the experience seems to be on MTBs.


Concerning chromed -- i.e. rust prone -- proprietary hardware -- aren't all bike brakes that way? Is that a reason to avoid this particular brake? I'm slowly changing out my other hardware for stainless or titanium. I have a good machine shop in Cowes on the Isle of Wight who make marine hardware for me out of stainless or alu -- they can do my bike hardware too, where there isn't a standard part which suits.

ThorUSA

cowes ... nice .. sooo what sailboat you got ..lol


just get one which is current and which people in bike shops are used to work with.
Sram Shimano Magura is all good stuff


by the way on your EX do u have disc brakes or v brakes ? if v brakes you are stuck with them
( there were different EX Jetstreams around )

Dockhead

My EX is an old one, one of the first ones made, with incredibly horrible V brakes.

Why am I stuck with them? The bike has caliper bosses on the suspension front and rear, and disk brake hubs. I think it's a simple bolt-up, no?

Dockhead

Still pondering this.

It occurred to me that feeling the contact point, and modulation are really important to me, and surely better with hydraulic.

But most important of all is that the brakes don't drag. Something which is hard to achieve with normal rim brakes.

Is there any difference in this respect between hydraulic and mechanical?

The BB7 brakes are not that much cheaper than hydraulic brakes! But will be much easier to install, with no faffing around getting the hydraulic lines the right length etc. -- I believe I can use the existing SRAM levers and cables.


AND . . . . . no one has yet told me how to figure out the right rotor size. I guess I can just measure from the center of the skewer to the inside of the caliper? Only problem is that means I'll have to order the calipers separately, wait for them, receive them, measure, and only then can I order rotors :banghead: It would be much easier if there were some way to find out what size rotors were fitted to the disk brake Jetstreams.

bargainguy

Well, I thought I pointed you in the right direction by saying all the Dahons I've seen use 160mm rotors. Perhaps Thor can verify this.

Not sure what you mean about rim brakes dragging. Dragging on what? A properly adjusted and centered rim brake, and a properly trued rim, do not drag. If you mean a rim brake which drags on one side of the pads, check brake centering and wheel true.

One of the reasons I don't use hydraulic discs on any bike I own is that they take awhile to set up and adjust properly. Setting up a mechanical disc is a breeze in comparison, and replacing a cable on a mechanical disc is also fairly quick and uncomplicated. I also don't want to take a chance that my brakes would give out suddenly if there are hydraulic line issues.

As I stated before, I like to keep things simple. I'm OK with mechanical discs as a step up from rim brakes on any bike, but hydraulics introduce a level of complexity I don't need, and I'd have to stock a bunch of extra stuff like hydraulic fluid and spare lines, maybe some connectors. With mechanical discs, all I'd have to stock is cables, housing and pads, because I would take care of my rotors. That's just me. I do just fine with rim brakes, so if and when a mechanical disc bike comes into my future, I'll be happy to deal with it.

ThorUSA

ok you might have disc ready hubs ..... BUT nothing on the fork or the frame to mount the calipers ...


I am pretty sure that all jetstreams which have v brake studs do NOT also have disc brake tabs ...


show us a picture of the fork left side close to the hub ... and the frame left side as well
most likely all this discussion whats better is pretty nil


Thor
p.s usually I put 160 mm front and rear rotors on folders.... for fun I also had one with a 200 mm rotor in front ... lol pretty overkill

Joe Remi

No. I don't know how I missed this before, but you can't jury-rig discs to a frame without disc mounts. You have v-brakes which work fine for your application if they're set up correctly. Any bike shop can put new pads in and adjust them if you're having trouble with it.

tds101 

Koolstop brake pads to the rescue!!! LOL!!!

ThorUSA

also .. you could switch the v brakes with Magura hs rim hydraulics. they do have plenty of power and good modulation..
other than that what tds says .. koolstops work great