Let's talk about brakes

I was looking for 20" weels for a trike I was building, other than haveing to have wheels built from scratch (I could not find 48 hole hubs with a disk mount flange, and a 20mm trough hole), I found some 20", 48 spoke wheels with 14mm axels on Ebay that the axel could be threaded over to one end leaving enough axel lenght to mount to the trike. As to the disk mount for the brake, I made a adapter out of aluminum that I bolted with 6 SHCS (10/32), and epoxy'ed it to the hub, with 2nd set of ( these are threaded) holes to mount the disk.
 
dogman said:
For some reason I was picturing in my mind a tadpole trike. one wheel would be ok, as amberwolf points out, with the disk on the left. Do tadpoles have both brakes on the left? if so no problem then.
There might be some issues with dishing though, using a rear hub on a front wheel, so sorting out the disk alignment could be a pain.
Click to expand...

My buddy who builds tadpole trikes has just bought hub brakes for the two front wheels, operated with levers. He has a clever lever gizmo he made that will apply both front brakes if either front brake actuator is gripped. He runs without rear brakes on the trike.

I am thinking about using disks for the front only, with a conventional caliper on the back. Front brakes, as you may know, contribute a lot of the braking force, while rear wheels skid too easily. So if there is a super-duper brake ont he front wheel, and an adequate brake ont he rear wheel, it should be OK.

It really sounds like the hub disk might work. I could take the 20" "rear" wheel, screw a hub onto it, and apply it to the front of the bike. This avoids the expense of spoking a special hub.

Hmmm ... Are rear wheel dropouts at different widths than front wheel dropouts? I'd go out and measure them but it is 2F out int he garage right now.
 
blueb0ttle2 said:
While we're on this subject, does anyone have a reccomendation for steel front disc-brake forks?
It needs to be affordable yet reliable, a friend of mine has an alumium disk-brake fork that we are replacing, so we can mount a motor :twisted:
Cheers.
Click to expand...


I've always taken steel front forks from 20" bmx bikes. I've built several recumbents this way, and it has served well. Even the cheapo wal-mart ones are plenty strong, and if you are installing a motor you don't care about light. Be careful they are not bent, kids tend to wreck them. Garage sales! Can't get them any cheaper. If you want brand names and new parts prepare to pay a lot.
 
What about hydraulic vs cable? With a recumbent, all of the cable lengths are longer than a standard bike - I end up using tandem cables. Handlebar is way up in the air, bike is a little long, and so the rear brake is like 4-5 feet from the actuator, front cable is longer than standard, too. Are the hydraulic lines set up for fixed lengths? Can they be lengthened in a home shop? If not, they would never work.

It seems like cable would be the way to go - simpler, easier to extend.
 
llile said:
blueb0ttle2 said:
While we're on this subject, does anyone have a reccomendation for steel front disc-brake forks?
It needs to be affordable yet reliable, a friend of mine has an alumium disk-brake fork that we are replacing, so we can mount a motor :twisted:
Cheers.
Click to expand...


I've always taken steel front forks from 20" bmx bikes. I've built several recumbents this way, and it has served well. Even the cheapo wal-mart ones are plenty strong, and if you are installing a motor you don't care about light. Be careful they are not bent, kids tend to wreck them. Garage sales! Can't get them any cheaper. If you want brand names and new parts prepare to pay a lot.
Click to expand...


Oh - I was assuming that welding on the threaded mounts for the disk brakes is a trivial task for your tool set. If not, then yeah, you'll have to order them special.
 
What about hub brakes? These are essentially like the old coaster brakes, but cable actuated. They have a lot of the advantages of disk brakes, with less complexity - you just yank on a cable. Work in the rain, probably more "stoppum" than rubber rim brakes. Has anyone tried them?
 
Well, Sheldon Brown seems to believe that good rim brakes are better than hub brakes, or disk brakes for that matter.

http://www.sheldonbrown.com/tandem-brakes.html

Rim brakes are at least easy to build out of junk bikes.

Maybe, on the other hand, I should go with a Scuffy Skillman sole brake. Does anyone remember this cartoon? If so, you were working on bikes a long, long time ago. Ten points to anyone who remembers Scuffy Skillman!
 
llile said:
Well, Sheldon Brown seems to believe that good rim brakes are better than hub brakes, or disk brakes for that matter.

http://www.sheldonbrown.com/tandem-brakes.html

Rim brakes are at least easy to build out of junk bikes.
Click to expand...
Sheldon was writing specificly about Tandems. when he died, they still hadn't adopted large disk rotors for the rear of tandems, which has now proven to work fine. The old 140mm and 160mm disks could cook on long mountian descents with 2 riders, but the big, thicker 203 and 250mm rotors are fine

Rim brakes are fine in dry weather with clean, straight rims in good condition. but when wet, dirty, or on a rim thats hit a few potholes, they aren't as effective. They also aren't as effective at the higher speeds an ebike can hit. up to 20mph, rim brakes are fine. Above 30mph, they can melt off.

His mention of hub brakes there was specific to tandems. In those cases, they would run a 2nd brake on the hub built as a drag brake, not a primary stopping brake. I've got a great finned Aria Drag brake ment for exactly that: A Drag brake. I plan to use on my bike, someday. 2.5 pounds of drum brake ment to disapate something like 1000 watts of heat
 
Greenspeed still uses front drums on their racing trikes. I guess they work fine.
otherDoc
 
Don't go for an aftermarket kit that makes a non-disc frame disc capable. Those have been known to be unreliable and dangerous on regular bikes. Imagine how bad the problem is at our speeds.

Best way to do it is just go front disc, or get another bike that already has a front disc... hint; mountain bikes depreciate rapidly ;)

Find yourself some used components on CL.. many mountain bike riders often swap our their stock brakes for avid's and such. They are always getting rid of old stuff, which often times ain't bad at all.

I got some tektros for $30 which have pad adjustability on the insides!! a used disc brake adapter cost me $5.. a used disc brake wheel i found for $20.. the rotor cost me $10. All in all, i spent $65
 
Tektros are not that great and for $30.00 you can get new Avid BB5's and it's all there rotor - caliper - pads. I picked up 2 sets of Avid BB7's for $100.00 + tax. Worlds of difference. Stops on a dime and you can feel the control when using them.

http://www.blueskycycling.com/product680_70_-2009-Avid-Mechanical-Ball-Bearing-Five-Disc-Brake-BB5.htm

Just food for thought. 8)
 
llile said:
What about hydraulic vs cable? With a recumbent, all of the cable lengths are longer than a standard bike - I end up using tandem cables. Handlebar is way up in the air, bike is a little long, and so the rear brake is like 4-5 feet from the actuator, front cable is longer than standard, too. Are the hydraulic lines set up for fixed lengths? Can they be lengthened in a home shop? If not, they would never work.

It seems like cable would be the way to go - simpler, easier to extend.
Click to expand...

I used cable disk brakes on my trike, extra long cables make the braking spongy at best. I Switched to hydros on my cruiser which also has very long lines, one finger braking very little pressure needed. Light and day difference, and a nice quality pair of Avid Juicy 3 hydros are under 150 bucks bucks its a no brainer IMO...

KiM

p.s fitting an extra long hose is dead simple ~5 minutes to fit and bleed...simple.
 
auraslip said:
Does anyone know how much it would cost to have a disc tab welded on a steel frame?
Click to expand...

6 pack if you take it to the right place .... having welding done in a fabrication shop
can demand hourly rates upward of 50 bucks...

KiM
 
I've had some experience adding disk brakes to bikes without original mounts. We live in steep mountain country, and our house is at the end of a steep 600m dirt road, which wears out rims quickly. The main road off the mountain has a long, steep descent which risks blowing tyres off from rim braking heat, which is no fun and expensive too. So disk brakes look like they may offer a solution to both of these problems.

Here's the rear wheel on my (significantly modified) Dahon Boardwalk, with brazed on, homemade disk mount. Pretty simple really. The mount is in the same plane as the dropout, and positioned for the 160mm rotor which just clears the chainstay.Disklite.jpg

Brazing is much less risky to the steel frame because it uses lower temperatures, but is very strong.

The disk is mounted on a Shimano Alfine 8speed geared hub, which is great.

I've bought my disk calipers and rotors quite cheaply from BMSBattery, when I've been buying Bafang motors etc.. I can't say if their quality is any good yet, but so far they work fine.

Bruce.
 
I found this site via the DIY Electric Vehicle site, and am glad I did. I've been lurking here for a couple weeks trying to learn a few things.

I've been interested in building some form of electrified locomotion for quite some time. So, here's the plan. Buy a bicycle I want to ride, get used to riding again, then convert to electric power. I bought a Schwinn Pointe Beach ladies bicycle about a week before I found this forum to convert.

Here's the challenge at the moment and I'm hoping someone can steer me in the right direction: The brakes do not perform well. They are caliper brakes that mount on each side of the wheel to the frame/fork at the bottom end of the arms the pads attach to. They aren't impressive and squeal quite loudly when I apply them. As I haven't ridden it too much yet, can I expect them to improve as they wear in, or do I need to do something to improve them?

I hate to electrify it and make it go faster than I can make it stop. I plan to buy an Amped Bikes lithium rear hub motor kit when this concern is sorted out. Thoughts or comments are welcome.
 
You might want to read up on the brakes section of http://sheldonbrown.com ; that's pretty comprehensive and should help you be able to adjust them to work better, or figure out what to replace to make them work right. :)
 
Front disc brakes are really a minimum for eBikes going over 20mph, or going down hills.
 
by amberwolf » Fri Jun 17, 2011 4:08 pm

You might want to read up on the brakes section of http://sheldonbrown.com
Click to expand...

Wow, there's stuff there that I never imagined. Plenty to keep me busy for a while as I try to maximize what I have. And, I am going to put my front brake on the right side, where I would reach on my old Kawasaki Ninja when I needed to stop.

by neptronix » Fri Jun 17, 2011 4:10 pm

Front disc brakes are really a minimum for eBikes going over 20mph, or going down hills.
Click to expand...

As I don't have internet at home, if my brakes aren't better after the adjustment issues are checked out, I'll be looking for info on going to a front disc.

I really appreciate the input!
 
I'll give you a bit of a background. I started out on a bike with cantilever brakes, because it was a light and simple bike with a steel frame.
I thought that bike was awesome until i went down a 5% grade.. lol.

Even going over 30mph, i do not find my 180mm front disc to be adequate. Building up the funds to do a 203mm front disc + fork that can handle it as we speak.

The more brake you can fit on, the better :)
 
Sounds like you are on the right track. I have found that the brake pad choice can make a huge difference. I had the best results with Kool Stop pads that were a reddish orange color. Also, you mentioned brake squeal, which is usually eliminated by toeing in the trailing edge a small amount. This will be covered in Sheldon Brown's material, but is easy to do by just putting a piece of cardboard between the leading edge of the pad and the rim as you tighten them down.

Good luck with your whole project. :D
 
Thanks for all the great help. I got home Friday and took the time to check over my brakes compared to what I of sheldonbrown.com and my brakes are a good deal better. I started by swapping the front brake from left to right and then I loosened the front brakes adjustment just a little. They are noticeably better and have far less squeal. I suspect that I'll do another brake pad adjustment this evening using Rassy's cardboard suggestion. Maybe that will take the rest of the squeal out. My pads do have the cone washer set on each side of the caliper frame, so that should be an easy task.

Neptronix, is there a thread here for where you converted to a front disc brake? I may be interested in that, too in the future.
 
Nep, how much do you weigh?

I've found the bottom line avid single digit rim brakes + regen total suitable and I tow a 100lb trailer.
Like $20 for the brakes and $10 for a lever. The other lever is an ebrake for regen.
They're enough to throw me over the bars if I wanted.

Perhaps you don't have your brakes setup well enough?
Basically, most people will say rim brakes and disc brakes have similar stopping power in good, dry conditions.
 
You must log in or register to reply here.

Similar threads

K
  • Locked
FORUM RULES -What are the posting guidelines at this forum?
Replies
18
Views
123,036
eCue
eCue
Back
Top