Rim Brakes, Motorized Bicycles & Miles -a cautionary tale

[BarelyAWake]

Much has been posted about brakes & some advise upgrading from coaster brakes to some type of rim brakes at least, to improve stopping power of course...

Thing is, I'm not that big a fan of rim brakes TBH - they don't work as well when wet, don't work at all in the ice & snow, they're a pain to keep adjusted properly and without a doubt have the worst wear rate of any type of braking system ('cept maybe sneakers lol) and by "wear rate" I'm not talkin' bout just the pads, while that can be made manageable with a decent set, it's the wear on the rims that's problematic - which is a far more costly & dangerous issue;

Yeppers, that's a six inch chunk missing outa the side of my rim. No, I didn't crash, but it was quite exciting there fer a few. I didn't crush it w/my brakes, all it took was a slight bump & the excess pressure blew the side wall across the road with a very impressive bang. I was lucky in a coupla ways, it just happened to be my rear rim & as I wasn't braking at the time and didn't try to brake the wheel that just had a blow-out - it didn't lock up on me & I just coasted to a stop, if a squirrely one.

Granted that's a crappy single wall alloy rim & I knew it was gettin' sketchy, even though that particular rim only has roughly 5000 miles on it - but even if it was a double wall I suspect it'd be well past it's safety margin & would need replacing, given how thin the side walls have become.

So... be warned. If you've rim brakes, or you're thinking about upgrading from a coaster brake and/or replacing the rims on your motorized bicycle, you may wish to consider spending just a little bit more and get a decent set of double wall rims with drum or disk brakes. If you can't or don't want to for w/e reason, remember to check your rims for wear periodically at least.

There's a reason why mopeds & whatnot don't use rim brakes & I think the above illustrates that quite well

 

[machiasmort]

Re: Rim Brakes, MBs & Miles -a cautionary tale

Good thread, excellent illustration and reminder! I like the flat edge refference point... Newer Chinese rims might be thinner!

 

[bandito]

Re: Rim Brakes, MBs & Miles -a cautionary tale

I always wondered about that problemo, I havn't worn one down like that yet but i'll be keeping my eye on the rim wear.......great post and thanks.

 

[Cogswelln]

Re: Rim Brakes, MBs & Miles -a cautionary tale

holy crap is all i gotta say

 

[2door]

Re: Rim Brakes, MBs & Miles -a cautionary tale

A very good argument for disc brakes. For anyone who accrues high milage on a pedal or motorized bike, this is a warning of what is possible.
Good presentation, Geoff. I hope everyone reads it.
Tom

 

[Elmo]

Re: Rim Brakes, MBs & Miles -a cautionary tale

That is why we inspect our bikes frequently.

 

[happyvalley]

Re: Rim Brakes, MBs & Miles -a cautionary tale

That is why we inspect our bikes frequently.

Good point. Anything that sees a lot of use will require maintenance. Keeping wheels true, rims surfaced and pads deglazed is just another part of routine maintenance for me. Rims wear as well, so replacement becomes part of that program.

Disc brake set-ups can be great but not all disc brakes are the same. I'd rather have well tuned linear pull or canti brakes with quality components on a decent bike than low quality disc on a cheap bike. You get what you pay for. Asymmetrical stress on rotor side fork blades creates torque steer and fatigue, as well as extra stress on rotor side spokes. Wheels should be dished and tensioned accordingly for it.

 

[The_Aleman]

Re: Rim Brakes, MBs & Miles -a cautionary tale

I never had that happen to any of my wheels. I had an MTB with alum wheels and centerpulls in the late 80's-90's that I put over 50k miles on and a cruiser with alum wheels and V-brakes I put over 30k on. Always used salmon Kool-Stop pads and kept things adjusted.

Lots of road salt in Maine, isn't there?

 

[Mannhouse51]

Re: Rim Brakes, MBs & Miles -a cautionary tale

Ouch ! Actually looked at my rims today and they were good. Never seen anything like that before.

 

[BarelyAWake]

Re: Rim Brakes, MBs & Miles -a cautionary tale

Well, a coupla folks have mentioned that with anything that sees a lot of use requires a greater amount of inspection & maintenance... obviously this is true and I agree, yet I'd like to suggest that anything that could reduce that amount of maintenance, thereby increasing reliability - is defo more than welcome in my book lol

I'll freely admit the usage this particular bike undergoes is brutal, it's my beater commuter after all - at least six days out of the week it's on the roads in any and all weather conditions at sustained "high" speeds (for a bicycle), riding on anything from clean dry asphalt, mucky trails or the wonderful ice and snow, a delightful mix of salty slush if I'm lucky.

...but that's my point - I've found the "normal" maintenance rim brakes require with the miles, speeds & conditions I ride excessive, surpassing any other component by a ridiculous margin. The only other component that comes close to needing nearly as much attention is the drive chain, and that's just a matter of the occasional adjustment & lube - not even tire wear comes close to the love the brakes constantly demand, only to reward that attention with questionable preformance when wet & failing me utterly when they're iced up.

It's so bad I often resign myself to simply not having brakes in the winter & riding accordingly... which honestly isn't something I would recommend to others or particularly appreciate - if I seem overtly negative, that could well be a factor lol

Is it a critical enough problem for the average rider that it's something they must do, converting their bike to another type of braking system? Not at all - with quality pads they're completely acceptable with good stopping distances & negligible wear, with recreational use in "ideal" conditions with the usual maintenance, even the rims should last just about forever. I posted this thread simply as a cautionary measure, that rim brakes do cause rim wear & it's something to keep an eye on. Pad drag from maladjusted tension springs, dirty and/or worn pads, any neglect will only compound this issue, as would the greater speeds, weight, heat, use and strain of a motorized bicycle application.

Yet by comparison, the Sturmey Archer drum brake hubs on my Rollfast have required no maintenance whatsoever, not even a glance or thought in the over four thousand miles I've had them - I squeeze the lever & they stop me w/o complaint or question, every time, even in a downpour. Granted, I don't ride that bike in the winter (it's shiny & I'd like to keep it that way lol) - but snow and ice don't effect drum brakes in any case. Sixty bucks to never hafta worry about braking or rim wear again may be something to consider.

Disc brakes, torque steer & asymmetrical stress on the forks? Conceivable yes, in practice I've found it's negligible to the point of being an academic curiosity at most - I've never felt anything even slightly noticeable on the disc setups I've ridden. It's true I've not tried the generic disc brakes on a wallyworld bike & with such low quality forks as they tend to come with that could be an issue - but in my opinion replacement forks should be considered if they're that flexy anyway... Forgive me, but I'm having trouble understanding how disc brakes could possibly put any "extra stress on rotor side spokes" as the rotor is connected directly to the hub & the hub is ofc connected to itself on both sides, being one piece & all... I could be wrong, but even so maladjusted rim brakes can flex the heck out of a rim & spokes, as does high speed cornering *shrug*

In any case "low quality disc" setups are simplicity itself to upgrade, provided you've the mounts ofc. An Avid BB5 caliper w/rotor & pads is a mere $36 - replacement pads 8-12 bucks, rotors 12-14... defo cheaper than replacing a worn out rim and they actually work in the rain heh

Run what ya like, but for myself & my riding habits I'll never buy another new bike equipped with rim brakes *shrug*

 

[happyvalley]

Re: Rim Brakes, MBs & Miles -a cautionary tale

Sorry if those concepts are difficult to grasp. Having built bicycle wheels for a long time, somewhere over 300 wheels for customers and a couple of shops, I would deem it far from an "academic curiosity". It will depend on what level of understanding we want to take it but don't take my word for it, ask any good wheel builder. Wheels made for use with disc brakes have asymmetrical spoke tension. I've had cyclocross racers experiment with disc brakes and tell me that using the front brake hard they've had rim flex to the left to the point of the tire rubbing the fork, something they never experienced with cantis. I can get much more technical with this but I don't want to overshoot. Perhaps an easy to understand context is why, in part at least, most motorcycles have gone to dual disc arrangements.

The overall load force is not any higher but the off-center loading will tend toward torsional flex of a fork not designed for it. Applying disc brakes under load will tend to steer the wheel toward that side and a fact some quality bike manufacturers have addressed by building asymmetrical forks with the one fork blade beefier than the other. This was also illustrated, IIRC on this forum, in a thread where a user had blown out a springer fork at speed on the side where a front disc brake had been fitted.

The Avid BB5 is an entry level mechanical disc brake, the BB7 is a little better with more rotor/pad options and adjustment features though both receive more than a little criticism on being finicky in that regard.

I am a big proponent of quality bikes and components to match, disc brakes certainly no less in that regard, but whatever the choices, disc or rim, there's no substitute for regular maintenance of either as well. Just noting some observations I've made first hand, take it or leave it, in the advent of broadening the discussion in the interest of safety, an always welcome component to biking I'd surmise, so I hope that no one feels provocation or put out by that. ~taps keys--scratches maximus gluteus--chuckles~

 

[happycheapskate]

Re: Rim Brakes, MBs & Miles -a cautionary tale

I am a big fan of v-brakes. The reason why mopeds don't use them is because they are naturally heavier, and rarely used for pedaling, so a few pounds for drum or disc brakes isn't any big deal.

They may be "outdated technology", but so are a lot of good utilitarian or classic things, like mechanized reel-type mowers, leaf springs on pickups, acoustic guitars, and soda pop in glass bottles.

http://blog.teamsnap.com/wp-content/uploads/2010/11/happy_kid.jpg

For someone building a motor assisted bicycle, rim brakes are still a very good choice, if they are used wisely. For someone who uses it as a bicycle, rim brakes can be very effective, even in wet weather.

Too many bike rims are throw-aways, though. If you use some heavy duty (thick!) double walled rims, and sand them for effective traction, you will get a lot of performance and life out of them.

The Magura line of hydraulic rim brakes is very pleasurable to use and very powerful! 24 hour racers and trials riders still use them widely. With beefy brake arches and linear pad movement, they eliminate the adjustment inconveniences of standard v-brakes.
Look around on E-bay and Amazon to get yours. You can convert a v-brake bike easily.

http://www.allweathersports.com/winter/snowcats.html
sno-cat wide rims for snow riding/fat tire riding, work with v-brake frames, no modifications necessary.

DH rims, for v-brake specific use, are probably not as common, but should still be widely available, through internet shopping.

http://3.bp.blogspot.com/_dDUHPa7Qg...AD4I/nmrlUwcDCug/s1600/Bike+Wheel+Rim+MTB.jpg

Making sure your brakes do not drag, and cleaning your rims and pads with rubbing alcohol, are good ways to elongate service life. I like to check my pads for possible embedded debris, and file them a little sometime in their service lives for good flat engagement surface and preventing squealing.

Remember, BSOs (bicycle shaped objects) are just not going to be equipped with heavy duty things. It is best to think of them as consumable commodities, the sum of their parts, rather than permanent vehicles.

I never had that happen to any of my wheels. I had an MTB with alum wheels and centerpulls in the late 80's-90's that I put over 50k miles on and a cruiser with alum wheels and V-brakes I put over 30k on. Always used salmon Kool-Stop pads and kept things adjusted.

Lots of road salt in Maine, isn't there?

 

[happycheapskate]

Re: Rim Brakes, MBs & Miles -a cautionary tale

I've been looking at the Worksman industrial bikes, as I'm looking to sell complete friction drive bikes. The steel frames, HD wheels, and drum & coaster setup or v-brake & coaster setup look like just the thing for a city bike.

"Yet by comparison, the Sturmey Archer drum brake hubs on my Rollfast have required no maintenance whatsoever, not even a glance or thought in the over four thousand miles I've had them - I squeeze the lever & they stop me w/o complaint or question, every time, even in a downpour. Granted, I don't ride that bike in the winter (it's shiny & I'd like to keep it that way lol) - but snow and ice don't effect drum brakes in any case. Sixty bucks to never hafta worry about braking or rim wear again may be something to consider."

 

[happyvalley]

Re: Rim Brakes, MBs & Miles -a cautionary tale

Making sure your brakes do not drag, and cleaning your rims and pads with rubbing alcohol, are good ways to elongate service life. I like to check my pads for possible embedded debris, and file them a little sometime in their service lives for good flat engagement surface and preventing squealing.

Remember, BSOs (bicycle shaped objects) are just not going to be equipped with heavy duty things. It is best to think of them as consumable commodities, the sum of their parts, rather than permanent vehicles.

Good points to remember, quality rims should last a very long time but a little preventative maintenance on parts will stay ahead of the curve on more costly and time consuming repairs. Excessive wear and cupping of rims faces is often the product of neglected routine maintenance, brake pads out of adjustment, installed misaligned to begin with or simply not soon enough replaced after wear lines are reached. Higher quality brake pads will last longer and also tend to pick less embedded hard material and aren't as prone to cause galling on alloy surfaces.

 

[Goat Herder]

Re: Rim Brakes, MBs & Miles -a cautionary tale

I have always used quality triple crown down hill forks with the biggest disk rotors I could get my hands on. None of the 6 inch crud. 203's I have never ever had a spoke issue of any kind what so ever. My wheels never pulled to the left or any silly stuff ever. They worked flawlessly!! I have front wheels with over 10K miles original spokes and some darn hard freaky punishing braking. Last I hardly even touch the spokes they just keep on going. 14 gauge too..

I carry grocery's on BMX style handle bars to the tune of 50 dollars a pop. Milk meat potatoes you name it. 10k miles easy baby!! Disk brakes are my all time favorites....

Grocery's the bike and me easily exceeds 300 pounds....

 

[BarelyAWake]

Re: Rim Brakes, MBs & Miles -a cautionary tale

...Wheels made for use with disc brakes have asymmetrical spoke tension. I've had cyclocross racers experiment with disc brakes and tell me that using the front brake hard they've had rim flex to the left to the point of the tire rubbing the fork, something they never experienced with cantis...

The overall load force is not any higher but the off-center loading will tend toward torsional flex of a fork not designed for it. Applying disc brakes under load will tend to steer the wheel toward that side and a fact some quality bike manufacturers have addressed by building asymmetrical forks with the one fork blade beefier than the other.

This is interesting and yes, you've given me quite a bit to chat abut with my wheel guy which is always welcome... & whom in all honesty may well have told me about asymmetrical spoke tension compensation when he built my last wheelset, double walled alloy 20"s w/36 4x 12ga spokes on 20mm disc hubs - which I suspect most likely wont suffer from much flex, or at least I hope not lol

As you'd surmise from the above, I don't build my own wheels. I prolly should - but as he's is an artist that doesn't charge nearly as much as he could I'm more than happy to hand him my oft oddball tasks as I attend to other things. The wheel pictured in the OP was stock, from a low quality box store bike - he had nothing to do with it BTW, nor will I be running such again, that build was jus' an experiment at the time & lessons learned, another reason for this thread lol

Yet, given my favorable experiences with mountain bike discs & forks, the lack of any noticeable flex (to me anyway heh) gives me cause to wonder if the difficulties cyclocross racers had with their disc brake experimentation & their preference for cantilever brakes has anything to do with their minimalist emphasis on mass reduction? Which may be less a concern w/bikes suitable for motorizing...

This was also illustrated, IIRC on this forum, in a thread where a user had blown out a springer fork at speed on the side where a front disc brake had been fitted.

Ahh, springers. Beauty in classic form, not so great in function it seems heh, yes I've a set of older (50s Schwinn I believe) springer forks & while those are quite durable, they are somewhat... loose, what with all the additional pivot points. TBH some of the modern reproductions have me concerned regarding quality & thus safety, most particularly the cheaper chopper variants w/their crimped fittings & long rake... do you know offhand which thread/what type springer that was?

The Avid BB5 is an entry level mechanical disc brake, the BB7 is a little better with more rotor/pad options and adjustment features though both receive more than a little criticism on being finicky in that regard.

I am a big proponent of quality bikes and components to match, disc brakes certainly no less in that regard, but whatever the choices, disc or rim, there's no substitute for regular maintenance of either as well. Just noting some observations I've made first hand, take it or leave it, in the advent of broadening the discussion in the interest of safety, an always welcome component to biking I'd surmise, so I hope that no one feels provocation or put out by that. ~taps keys--scratches maximus gluteus--chuckles~

Yes, the BB5s & 7s are entry level disc setups - offered as alternative replacements for entry level rim brake setups. Given the maintenance required with these lower cost variants & the consequences of use & abuse, between those two choices - personally I would choose the discs for their lack of rim wear, reduced maintenance needs & better all weather preformance. In part as a result of our conversation, but mostly due to the demands of a constant all-weather commuter - my next "beater bike" will most likely receive drums as their indifference to water, ice & snow, their reliability & low wear rate, and their lack of a need for such constant attention as rim brakes makes them the clear winner for that application in my book.

I suspect what it boils down to is a combination of application & budget, as does most things. I've no doubt that "well tuned linear pull or canti brakes with quality components on a decent bike (are better than) than low quality disc on a cheap bike" as I also suspect that quality discs on a good wheelset & forks would offer comparable results. Ofc as the sky is the limit when discussing higher quality components, I bet we could go round & round on that one almost infinitely w/o a definitive conclusion lol

Again, I cannot agree enough with the observation that there's no substitute for regular maintenance, most particularly with any bicycle that undergoes the additional strain, speeds & miles as one that's been motorized. The rims pictured were low quality components subject to both abuse and admittedly neglect - the consequences thereof I thought important enough to share, some of the lessons I've learned in my motorbicycling adventures. Part of that lesson is for my use, rim brakes are simply too demanding, for me not worth the effort for their somewhat unreliable performance when there are viable alternates that don't require such unrelenting attentiveness. There have been valid points brought up regarding the advantages & disadvantages of the various braking systems, which compromise is best suited is ofc going to always be up to the rider and their specific needs & preferences.

 

[Ibedayank]

Re: Rim Brakes, MBs & Miles -a cautionary tale

cycloracers don't normally use 36 or 48 spoke wheels either
expose diskbrakes to heavy use in sandy and salty condiotions with extra heavy use and the rotors and pads will not last long either

 

[happycheapskate]

Re: Rim Brakes, MBs & Miles -a cautionary tale

I'm impressed with the heavy duty forks and hydraulic disc. I don't really care for the cable discs or conversion stuff.

I wish someone made a steel rim set that looked sort of like a brake rotor, about 1" tall with standard spoke holes, vent holes or laser cut slots on the sides above the bottom wall and bead hooks, and standard tube tire interface, with thick sidewalls that could be "turned" if you ever did start showing wear on them. They would have massive braking power and could use wide pads, and probably would be really long lasting.

The strongest wheels I ever had were Alex street jumping wheels, 20" with 48 thick spokes, felt like motorcycle wheels. I landed a jump and flatted, hit a hard surface with them and only found a ding in the metal that I filed out. I have a set of Alex "DH" rims on a coaster brake cruiser set, and they look pretty stout to me.

Look into dirt jumping rims.

 

[The_Aleman]

Re: Rim Brakes, MBs & Miles -a cautionary tale

I can't put discs on my bike, due to the fact I have drum hubs. My 70MM drums aren't quite up to the task of stopping me quickly.

So what to do to improve braking, I asked myself rhetorically and literally...V-brakes and drums together!

Add white Kool-Stops and Problem Solvers cable doublers and BAM

 

[happycheapskate]

Re: Rim Brakes, MBs & Miles -a cautionary tale

I've never seen that before! (drums actuated by the same levers as v's). I've seen "drag brakes" on tandems, though.

If your drum brakes aren't doing it for you, have you cleaned them out and adjusted them? Are there any other shoes available for you?

What do the white v-brake pads do differently?

I have used the black ones and red ones.