Monday, January 21, 2008

Chain Stay

The chain stay is often the most overlooked component of the frame. Possibly due to the fact that its tuck away under your tush and generally has more interesting components of the drive train packed around it. For this exact reason I thought of checking out what type of performance issues the chain stay affects. Here are a few quotes from various websites with the statements regarding the chain stay and how it affects performance.

"Venus C7 ovalized tubes and box chainstays for lightning-fast acceleration, razor-sharp handling and ultra-low weight"

"combined with the 17in chainstays made for quick acceleration and stable handling at speed"

"Short 15.75in chainstays keep acceleration ultra snappy"

"short, stiff chainstays improve acceleration and tuck the rear wheel beneath you for optimum climbing traction"

So how does the length actually effect the control you have and why is acceleration increased by shortening the chain stay. It does seem though that things like weight of the bike and even tire selection would be greater factors as to why you can accelerate faster than a shorter chain stay?? Even the fork can effect how fast you could pull away or get back up to speed after a tight corner but these statements are found time after time.

Well there are two obvious features that could help in terms of weight savings thus less mass to try to get going. The shorter chain stay has less material and so does the chain because you have shortened the length needed. These seem like two small changes but seem to me about the same as shaving off the extra length of your fork tube or changing pedals. To see benefits of weight savings the best places to start are the areas of rotational mass, so it could help in terms of acceleration. But as I dug deeper the actual reason was that you get a greater power transfer with a shorter chain stay. More power = faster acceleration.

The other main factor bandied around with shorter chain stays are that the handling is much better. This I can understand because your wheel moves forward and under your tush. Your weight would also shift over the back wheel making the bikes climb better. Handling however has more to do with the fact that you have shortened your overall wheel base so you can make tighter turns.

However as Newton taught us what goes up must come down. When heading down the hill you seem to loose the stability that a longer chain stay would give you. Here again its down to the wheelbase shortening. Think about it as a ship versus speed boat, the latter would corner like a king but try loading it up and you might start rolling about like a hyperactive kid on a rocking horse. For a more stable ride you would rather opt for longer ride as most touring bikes have or even the new Kona UTE.

Another thing to look out for is chain suck and mud clearance of the wheels. With chain suck the chain fails to disengage from the bottom teeth of a front chain-ring ; instead the teeth snag the chain and carry it up and around the rear circumference of the ring, winding it back onto itself, and jamming it between the chain-rings and chain-stay. Doesn't sound pleasant and luckily, touch wood, has happened to me.

So as you can see there are benefit's as well as drawbacks but looking around on the various manufacturers websites you will find that they normally range in the 17" ranch. I will check that up and then then get back on the chain stay length's of some manufacturers and post what they are.
Related Posts with Thumbnails