Is it wise to change the gear ratio of a folding bike?

[pengyou]

I have talked to a lot of people about folding bikes...most really like theirs, as long as they bought a decent one....but all usually include the same comment "but they are a little slower than other bikes", as though it were a bad thing. If this is a problem, why don't people just change the gear? Is it unadvisable given the size restrictions of a small bike? too much pressure on some part of the bike? or is it that no one has thought to do it, or it really isn't so important?

Just based on simple principles of geometry it seems to me that a person should be able to easily compensate for the small size of the wheel by change a gear - or combination of gears.

[LittlePixel]

People that say folding bikes are slower not necessarily wrong, as the majority of mid-market bikes are meant to appeal to a wide range of riders and uses. But similarly - a 26" wheeled town hybrid probably isn't as fast as a carbon road bike either so it's a bit of a silly argument. In the end it all comes down to the gearing and engine. Top end folding or small-wheel bikes, or ones that have been upgraded have no trouble keeping up with or being equal to 'normal' sized bikes - the small wheels accelerate more quickly in fact and the only real caveat over 700c wheels is a smaller rim's sensitivity to bumps and potholes.

It's funny - a tractor has big wheels and a Porsche 911 has small ones but no-one ever has problems estimating which two of those is faster!

If you do a bit of digging on the web you may be able to find some information on how the world bicycle speed record was set by a 16" wheeled Alex Moulton designed track bike with appropriately high gearing. So it's really a fallacy that a small wheeled bike 'has' to be slower, but in real life - yes some are to appeal to as many different riders as possible, but a lot aren't - just wait for more comments from some of the speedsters in this forum who ride their Bike Fridays, Swift's, Airnimals and even Raleigh Twenty's as fast as the rest of the pack on group and tour rides.

[onbike 1939]

An Airnimal Chameleon came second in the Ironman. I certainly can't push mine as hard as it's capable of.

[Bacciagalupe]

My guess is that most people who say that "folding bikes are slower" haven't had much experience with them. ;) My Dahon was about as slow as my hybrid, and my Swift is around the same as my road bike (albeit less comfortable).

As to gearing, the vast majority of folding bikes only come with a single chainring. As a result, the gearing range is a little limited compared to larger/normal bikes.

However, the only time that gearing will impact your performance is on the hills. Specifically, if your bike is set up for low gearing, you'll be slow on the descents as you do not have big gears to push. More likely is that your bike will have a medium range, so you may need to spin harder to get up hills, and probably can't pedal faster than 28-30mph on the downhills.

One minor advantage of this setup, by the way, is that shifting is a little simpler than most other bikes. One shifter and you're all set.

[cooker]

I have a full size tour bike and a Bike Friday. The Bike Friday with a triple chain ring and the capreo cassette has a wider gear range than the tour bike, and it is set up with similar geometry. So it's just as fast on the flat, and faster on the downhill.

[awetmore]

I have talked to a lot of people about folding bikes...most really like theirs, as long as they bought a decent one....but all usually include the same comment "but they are a little slower than other bikes", as though it were a bad thing. If this is a problem, why don't people just change the gear? Is it unadvisable given the size restrictions of a small bike? too much pressure on some part of the bike? or is it that no one has thought to do it, or it really isn't so important?

Almost all folding bicycles already have higher gear ratios to make up for the smaller wheels. For instance the Bike Friday Tikit comes with a 52 or 53t chainring and an 11-28 cassette. It is 16" wheels. This is comparable to a 32t chainring with the same cassette on a 700C wheeled bicycle.

You could go larger on the chainring, but it affects the folded size of many bikes. The larger rings are also harder to find, more expensive, and generally more fragile.

This is one reason that internal hub gears are so popular on folding bikes (an internal hub gear, by itself or with a rear cassette, lets you get high gears without huge chainrings).. It is also why Shimano makes the Capreo group which uses a special 9-26 cassette.

I think most people find folding bicycles slower from the higher rolling resistance of the small wheels, the general utilitarian design of most of the bicycles, and the short seating position that doesn't let the rider get into as efficient of a riding position. There are folding bicycles which improve on these areas and that tend to keep up more closely with other bikes.

Changing tires can make a huge improvement too. Most of the small tires are like the Schwable Marathon -- very utilitarian and bullet proof. A lighter and more supple tire like the Avocet Fasgrip or Greenspeed Scorcher can make a noticable improvement in performance and handing, at the cost of getting punctures more easily.

alex

[James H Haury]

The bike needs to suit the user.If you want to ,change the gears to something more suitable for you.You can always change it back.