Friday, December 30, 2011

BIKE REPAIR: The Penny Trick

Hope you're all getting ready for a fun New Year's celebration,

Here's a bicycle repair trick that I wrote about last week in my Jim's Tech Talk column. In case you missed it, here it is with wishes it comes in handy sometime in 2012. It has sure saved me some frustration and skinned knuckles over the years.

I didn't mention this in my column because I didn't remember until the other day, but the trivia on this nifty tip is that one of Santa Cruz's cycling visionaries, Ross Shafer taught it to me. He's the bike guru that created the company Salsa that you're probably familiar with. Great guy with an amazing bicycle background you can read up on.

Remove/install that part the easy way
With no further detours, here's Ross' Penny Trick - or how to outsmart ill-fitting parts (rather than them outsmarting you!

This trick is a cool way to deal with annoying fits, like a seatpost binder (the binder is the clamp built into the frame and used for tightening the seatpost) that’s so tight you’re afraid you’re going to scratch your pristine seatpost inserting or adjusting it, or a modern 2-bolt Shimano crankarm that’s stuck on the bottom bracket axle, tempting you to break out the big hammer and teach it some respect.

Don’t do it. Use this elegant trick. It works on single-bolt stems that are so tight you can barely get the handlebars in, too.

The photo shows the basic setup you want to achieve. It’s not possible with every component, but often you can remove the bolt(s), reverse one of them (see tip below) and thread it into the other side of the part. Just thread it in partway.

Then take a penny (or a dime if a penny is too thick - washers will work, too) and place it beneath the bolt to give the bolt something to push against. Make sure the edge of the penny doesn’t protrude to the inside or it will get in the way when you install/remove the component.

Now, by tightening the bolt little by little, it pushes on the penny and that opens the crankarm, stem or seat binder wider making a formerly impossibly tight part into an easy slip-on!

Tip: This is a little difficult to explain and with different components you’ll have to look at them and figure out whether it will work and how to make it work. Please study the photo to understand the principle. If there are 2 bolts, as on the Shimano crankarms, be sure to fully loosen or remove both bolts and don't drop and lose the little plastic keeper that's held by the inside bolt!

UPDATE January, 2012: Since writing this tip about the penny trick for installing tight-fitting bicycle components, Jan Heine of Bicycle Quarterly (one of my favorite magazines) has posted an excellent article on the penny trick (he uses a quarter or dime) for installing handlebars into stems. Yes, it's a no-brainer to put handlebars into modern road and mountain stems with removable faceplates. But the penny trick is for one-piece stems that are sized exactly right for the handlebar and can't be taken apart.


Kage said...

This is far more elegant than what I do: lube up and slide a flat head screwdriver to shim open the gap just enough.


Jim Langley said...

Glad you like the tip, Kage. The "penny trick" also won't risk damaging the parts either, the way putting a screwdriver can if you slip, or force it or use the wrong screwdriver. There are also "spreading pliers" that can work, but to use them you have to keep squeezing the whole time as you fit the parts together. That's not always easy to do. So this trick comes in real handy. Thanks for the feedback! Jim

SpeedyChix said...

The old style Moots seatpost clamps can use this trick as well though a quarter is the better thickness there.