What are the reasons someone would want to ride a road bike with ZERO or say 25mm setback??
I know you TRI guys talk about hip angle… but on a road bike is there benefit to riding with a ZERO??
You can reproduce very closely the hip angle at BDC on both a road and tri bike. Most good fitters will do this by using setback on a road bike for a few reasons. One of which is to keep the frame handling the way it was meant to handle. It’s not difficult to control hip angle on a road bike b/c you are not locked into a position like a tt bike when in the aero position. A slight extension or compression of the arms can change the hip angle at BDC on a road bike a lot. It can certainly work across the full spectrum though I have seen animals riding on very odd looking setups who drop the pack and ride off into the sunset. Whatever works…works. You have probably read or heard this, but if you have the tt fit nailed then getting the road fit done is cake. Simply you are just rotating the rider back around the bb to a slacker position.
Example. My Adamo Road setup for a road bike is slammed full back on a 20mm setback post. For tt it’s nose is directly over the center of bb. Hip angle in default hood position on road is spot on to aero tt position hip angle at BDC. Is there a benefit to riding a zero setback? If it helps you get into a position you want then yea! I just set up my road as closely to my tt so that when I switched back and forth it felt very similar in my pedal stroke.
Fairwheel Bikes did a test a while back and, on the whole, zero setback posts are stiffer. You also want to get a rider in a position that is a comfortable as possible and allows them to produce the most power.
Everyone has some ideal hip angle range when they ride, and what seat post setback that implies will depend on how upright their position is on their roadbike, and what the riders seat tube angle is on their frame, and how high their seat is.
So, yes, some people will want zero setback. Especially on bikes designed with a slacker seat tube, so as to make it more likely that a zero setback post is preferred, to save a few grams of weight.
Anyway, just put the saddle where it makes your legs feel good. Use whatever post makes that happen.
What are the reasons someone would want to ride a road bike with ZERO or say 25mm setback??
I know you TRI guys talk about hip angle… but on a road bike is there benefit to riding with a ZERO??
It’s related to your bike fit, specifically femur length and flexibility in lower back/hamstrings. The longer the femur, the more setback you will need. It’s not that one is better then the other, but one if better than the other for YOU.
What are the reasons someone would want to ride a road bike with ZERO or say 25mm setback??
I know you TRI guys talk about hip angle… but on a road bike is there benefit to riding with a ZERO??
Sure, there are a few. Getting more forward (w/ the use of a zero setback post, plus maybe sliding your seat forward on the rails) allows you to, all other thing being equal, get a significantly lower torso without the penalty of a highly acute hip angle. And that usually means less drag without a hit on power (= more speed).
For an example, here is a pro’s bike set up like this:
You want the saddle rail clamps to be directly under the pressure point you make on the saddle so as to not introduce more cantilever moment into the rails. Usually this requires a rearward offset of the clamp.