Saturday, May 1, 2010

Q&A: Carbon frame repair, learning bike mechanics, disc brakes

Happy Bike Month! Be sure to join the pedaling party and get a free breakfast at B2W stops on your way biking to the office on Bike To Work Day on May 21. Here are three fun recent Tech Q & A's from my inbox:

The amazing Calfee Designs Bamboo bicycle!Q: Hi Jim,
I have a carbon bicycle and someone in a car just hit me from behind. Luckily I wasn't hurt much. Unluckily though, my frame was damaged. I don't know if it's broken completely but I see cracks in four different places. I would like to know how much it would be to repair it? If you can give a place where to repair it in Los Angeles that would be great because I don't want to ship it. My other question is will it ride the same and will it affect the frame?

Have my fingers crossed,

A: Hi Jorge,
If you got hit from behind hard and see cracks, you are probably right that your frame is damaged, and it sounds serious to me. To be sure, why don't you give the carbon wizards over at Calfee Designs a call (they're located in La Selva Beach, only 10 miles from my house).

They should be happy to talk to you about it on the phone. While they're not in LA, they've been fixing carbon bikes since the material first appeared on frames, and they really know their stuff. If you don't want to ship your frame, you could drive the bike up here. It's about a 6-hour drive from LA and worth it to be able to talk to them and show them your bike in person.

I know several excellent racers who have had Calfee fix their carbon bikes and they all say that the bike rides and looks just as good after the repair. So if they can fix your bike - and I believe they can fix just about anything - I'm sure it'll be as good as new.


Q: Jim,
I am a 51 year old woman who has always wanted to take an old bike frame and build it up into something rideable. Please could you tell me if there are any online courses one can do to learn this stuff or can you recommend books for this purpose? I look forward to hearing from you.

Kind regards
Natalie in South Africa

A: Nice to hear from you, Natalie. It’s not all that complicated to build up a bicycle from a frame. You only need an assortment of the right tools and the right parts. Probably the easiest way to do it and learn in the process would be to find a friendly and good local bicycle shop, tell them that you’re interested in doing this and see what they recommend. They might actually have a used or cheap new frame to get you started and they would certainly have, or be able to order all the parts you need. They would then be happy to help you build it, since you purchased the frame and parts from them.

Alternatively, you might call local bicycle shops and ask if they offer basic bicycle maintenance classes you could attend. If so, you could meet the instructor and tell her what you plan to do and see if it’s appropriate for the class. I had this exact thing happen at one of my classes and even though it was basic repairs only, I was happy to take the extra time to help the student build his dream bike.

If you can’t find a bike shop teaching bike maintenance you could try asking if they would teach a class if you rounded up some friends who would pay to take it. That’s a good way to convince them they need to do it and they should make some money selling books, tools and parts, too, so they just might do it if you ask nice.

You could also check at local colleges to see if any offer a community outreach or recreational class in bicycle mechanics. Lots of colleges do this and since it’s a recreational (not a credited course) it’s often open to the public for a fee. Sometimes a city will have a summer program class like this too. Here you would find out about this in the newspaper calendar.

And, yes, there are plenty of books out there on bicycle maintenance including some of mine that you would learn a lot from. But it’s the hands-on that teaches you. The book is best as a guide to follow. You can pick up bike repair books for next to nothing at used book stores since so many have been sold over the years. The best thing is to browse through a few and buy the ones that are easiest for you to read and understand, and that cover the bicycle type you plan to work on.

Hopefully you’ve already found all the pages I have on my website full of tips and advice on fixing bicycles too. There’s all kinds of helpful tips on my site and it’s all geared for anyone. You don’t have to be an expert. And, anyone can work on bikes. It’s all easy to learn and do by anyone with basic mechanical skills.

A great online video resource where you can pick up lots of helpful information fast is Bicycle Tutor. Be sure to visit their site and watch because they offer everything from beginning to advanced procedures.

I hope this gives you the confidence to get started. Feel free to ask me any questions and I’ll help you as quickly and thoroughly as I can.

Also, keep in mind that, like the foundation of a house – if it’s all rotten or sinking into the ground – you can’t build a good house on it. A bicycle frame is the same way. If it’s rusted, bent, damaged, dented, etc., you won’t want to build a bicycle with it. Another issue is compatibility. If it’s an old frame it could have unusual dimensions or threading which would result in difficulty finding parts that fit. And, lastly is quality. Even if the frame is in good shape and has current dimensions to accept modern parts, if it’s made of cheap, heavy materials, it will result in a bicycle that doesn’t ride very nicely.

So, before you start you might want to get a second opinion on the frames to make sure you are starting with something worth building on. Also, if you plan to ride the bicycle, you want to make sure that the frame is the right size for you too. Maybe you already did that, but that’s very important if you’re going to ride the bikes.

Have fun!

PS: I realize you're in South Africa, but it's possible there are actual bike repair schools/colleges there like we have here. Two pretty famous ones are Barnett Bicycle Institute and United Bicycle Institute. These are real mini colleges where you take a week's worth of classes to learn to be a bicycle mechanic and get hands-on experience working with experts. United even has a course called Introduction to Bicycle Maintenance for Women. The cost is currently $675.


Avid's Juicy 3.5 disc brake!Q: Howdy Jim,
I'm planning to purchase a new mountain bike for commuting in wet weather only. My question regards the type of brakes a $400-500 "throwaway" bike offer. The traditional long-pad brakes work well when wet. Do the newer disk brakes offer the same stopping power?

I am a longtime roadie and only use a mountain bike for foul weather, equipped with fenders and slicks (of course).

What do you think?

A: Hi David,
Yes, the disc brakes work great, better than rim brakes in wet AND dry conditions, so don’t hesitate to get a bike with them. I’m assuming by throwaway bike, you mean a brand-name bike, but an inexpensive bike. Those will have quality discs even if they’re inexpensive ones. If you buy a bike from a department store, though, you could end up with bad discs. But, any bike shop mountain bike with disc brakes should stop better in all conditions than the same bike with rim brakes.

One thing you might want to do is visit a bike shop, tell them you’re shopping for a bike and see if you can test ride a few bikes. If you get to compare discs versus rim brakes I think you’ll see that they work better. Note that new bikes have new disc brakes and they work better as they get used. Rim brakes work fine from the beginning. But, discs have to be “burned in” a process of the brake pads heating and burning some of their material into the rotors (the metal discs on the wheels). Until this happens, the discs won’t perform as they are designed to. Some bike shops know this and take the time on each bike build to burn in the brakes. Other bike shops don’t know this and don’t do it. So, if you try a bike with disc brakes that doesn’t stop well, get up to a cruising speed and apply the brakes steadily until you come to a stop. Repeat this a few times and you should feel the brakes start to work the way they should.

Sorry for the long explanation, but disc brakes are still relatively new and there’s a learning curve to setting them up right. Once discs are burned in, I think you’ll be very impressed with their performance. Other benefits include no worrying about damaging the rims since the brakes aren’t dependent on the rims, longer lasting brake pads, less adjustment, and in the case of hydraulic brakes (significantly better than cable-operated disc brakes), no more cable issues.

Hope this helps and have fun picking out the perfect bike!


Yokota Fritz said...

Disc brakes on mass retail bikes?

Jim Langley said...

It is a little surprising, but I can remember disc brakes on bikes sold as Sears, etc. in the seventies, well before they ever made it to retail bike shops, and they didn't work well then either. In fact, bicycle disc brakes probably would have taken off a lot sooner had there not been so many bad disc brakes sold that convinced everyone they wouldn't work on bicycles.