Saddle setback
 

I was just wondering… If the rear tire wears 2-3 times faster than the front tire on a road bike, is this a sign of saddle set too far back?

That sounds about normal for my rear and front tire wear.

And my saddle is considered by others to be a little forward of ideal.

No. That's a pretty typical wear rate for a rear tire on a road bike.

It sounds good, because I found my b_t very often at the back edge of the saddle and I was thinking to move the saddle 1-2 cm back (meaning just a few mm behind the central position)...

What do you mean by "central position" - center of the saddle rails?

No.

What is b_t? In any case:

A spelling error, probably. It is that part that stays on the saddle :).

Yes.

All sorts of other names for it if one thinks butt is offensive. More properly it's buttocks.

cheeks
seat
bum
tail
rump
butt
posterior
backside
rear
buns
derriere
fanny
bottom
haunches
behind
booty
tush
derrière
hams
caboose
nates
breech
fundament
tail end
rear end
beam
heinie
duff
keister
bootie
can
keester
stern
hunkers
moon

https://www.merriam-webster.com/thesaurus/buttocks

The amount, or percentage of body weight on the rear wheel doesn't change due to seat position on the seat post. That same amount of weight is transferred thru the seat post, to the seat tube and onto the rear triangle, regardless of saddle position.

Being at the center of the rails isn't important in any way. Depending on the setback of the post, and the geometry of the frame, anywhere on the rails might be the correct position for your body, including all the way forward or all the way back. Your comment about finding yourself at the rear edge of the saddle a lot is a strong clue that maybe a rearward shift of the saddle might be a good adjustment for you. Try it. See how it feels.

Not true. The angle, orientation or length of the seatpost has nothing to do with how weight is distributed on the bike. If that was true, a Softride bike would have no weight on the rear wheel.

Only the saddle and rider location in the saddle dictate weight distribution.

Umm…. Any weight you put on the saddle gets transferred via the seat post and seat tube to the rear triangle. If you push the saddle all the way forward or back on the rails, all that weight still can only transfer via the post and frame. Seat location isn’t going to change how quickly a tire wears.

That isn't how center of gravity works. It is where the weight is, not how it is connected to the bike. You can't fool a scale just by connecting the seatpost somewhere else.

Anyone who has spent time riding a MTB uphill on loose surfaces quickly learns about how to shift your weight to improve traction of the rear tire. You don't even need to be sitting on the seat.

So youre agreeing with me, right?

Correct. Where the weight is attached to the bike is irrelevant. Where the COG is in relation to the wheels is what matters in this discussion. Someone riding a wheelie or manual is another example.

If we rode 2-wheel-drive bikes maybe front tires would approach wear levels of rears.

As it is now, with just the rear tire providing propulsive traction – as well as a relatively (and varying) greater percentage of the weight of bike and rider – we can should expect rear tires to wear faster than fronts.

Sort of why teeter totter's work. The person on the high end has to lean back or scooch back to go down or the person on the low end needs to lean forward or scooch forward. Kindergarten stuff.

Not correct, by moving the saddle, you change the center of gravity on the bike, changing the amount of weight that is supported by each wheel. However, the total weight is the same.

This would absolutely be true if you rode a bike with no hands on the handlebars and no feet on the pedals. However, riders obviously apply weight to these other contact points.

Your language ("That same amount of weight") lacks necessary precision. Yes, all the weight from the seat goes down the seat tube. But if adjusting the seat moves weight to the handlebars, then the amount of weight on the seat is no longer "the same amount".

No, this would not be true, either.

If you ride your bike hands off and you are sitting straight up with 3cm of setback, you will have less weight on the rear wheel than if you rode identically but with 6cm of setback.

And if you were able to move your saddle so far back that it was behind the rear axle, your weight shift would be so great that the front wheel would come off the ground.


All with the same seatpost location.

Try moving your saddle back in small increments -- start with 1cm -- and see how it feels. Pay particular attention to how your knees feel after a long ride - if they are sore, then put the saddle back where it was.

There is a method for positioning the saddle, but I have found that I definitely prefer mine to be set back a little further than is technically "correct," and it has been fine for 20+ years and 100k+ miles.

Excellent points. We were getting too focused on "weight" going here or there. As you point out, there are other forces at work that affect the final weight on each wheel beyond just the weight bearing on the seat, handlebars, and pedals. The swept back angle of the seat tube and the setback of the seat create a twisting force pulling the front of the bike up - the top of the seat post pushes backwards against the seat tube while the bottom of the seat post pushes forward against the seat tube.

It's all those burnouts...