bikeinsights.com

[henrypretz]

I found this website while I was googling around for info/input about running 650b on my steel Niner RLT9. It enabled me to input the specifics of my setup and get what I assume to be a true comparison of the two configurations.
I wondered if anyone here had seen it or perhaps could use it.

https://bikeinsights.com/

This is my inputted comparison
https://bikeinsights.com/compare?geo...d95600177d7d35

FWIW initial observation from one 3 hour ride is that the extra volume of the 650b tires REALLY softens and calms down the front end steering and handling, as would be expected. Another bonus for my 50cm frame is a bit less toe overlap, which is never a bad thing. So, so far so good and I'm looking forward to more rides on both wheel setups.

g'day
Henry

[mhespenheide]

I love the idea behind the site, but shouldn't the trail change when you switch to a different outer tire diameter?

This diagram doesn't directly show what I'm talking about, but imagine raising or lowering the ground level here -- the width of the base of the triangle created by the line through the fork blades above the curve and the vertical line dropped from the front hub would change, which means that the trail should change.

[henrypretz]

If I read the chart correctly, the trail did change with the wheel change

700c 77.3 72.8 ~trail
650b 72.3 68.2 ~mechanical trail

*Trail
The distance between the point where the steering axis of the front wheel intersects the ground and the point where the front tire contacts the ground. In this sense, the contact patch of the tire “trails” behind the steering axis. The greater this distance, the “higher” the trail and the lower the distance the “lower” the trail.

*Mechanical Trail
Mechanical Trail (Front Normal Trail), describes the distance between the point where the front tire contacts the ground and the steering axis, measured perpendicular to the steering axis. Some consider this measurement to be superior to Trail because it is not skewed as Head Tube Angle slackens.

That said, I honestly don't have a good idea of exactly what higher or lower trail numbers do to the handling of a bike. Time for more reading.

[weiwentg]

Originally Posted by henrypretz

If I read the chart correctly, the trail did change with the wheel change

700c 77.3 72.8 ~trail
650b 72.3 68.2 ~mechanical trail

*Trail
The distance between the point where the steering axis of the front wheel intersects the ground and the point where the front tire contacts the ground. In this sense, the contact patch of the tire “trails” behind the steering axis. The greater this distance, the “higher” the trail and the lower the distance the “lower” the trail.

*Mechanical Trail
Mechanical Trail (Front Normal Trail), describes the distance between the point where the front tire contacts the ground and the steering axis, measured perpendicular to the steering axis. Some consider this measurement to be superior to Trail because it is not skewed as Head Tube Angle slackens.

That said, I honestly don't have a good idea of exactly what higher or lower trail numbers do to the handling of a bike. Time for more reading.

Some interesting reading at this Cyclingtips article, but bike handling is complex. Generally, as long as we're in the same category of bicycle, more trail = more stable bicycle.

[mhespenheide]

Originally Posted by henrypretz

If I read the chart correctly, the trail did change with the wheel change

700c 77.3 72.8 ~trail
650b 72.3 68.2 ~mechanical trail

D'oh!

My mistake; I saw the larger differences highlighted and assumed that the site highlighted all of the differences. The more subtle difference in trail is given, but not highlighted. Back to being a cool comparison tool!

[mhespenheide]

Originally Posted by weiwentg

Some interesting reading at this Cyclingtips article, but bike handling is complex. Generally, as long as we're in the same category of bicycle, more trail = more stable bicycle.

There's also this, on RedKitePrayer, specifically talking about trail: https://redkiteprayer.com/2019/09/understanding-trail/

[cmg]

Higher trail=stable= bike wants to go in a straight line= can let go of bars as long as your going straight= not twitchy = slower steering , more input from rider to turn.

Lower trail= faster steering= rider needs to pay attention= can let go of bars but the bike may turn = twitchier steering. if the steerer tube were 90 degrees to the ground the trail would be zero and the bike would be very difficult to ride, any input could change steering.

[Malinois]

I really like this site and have previously contributed to the database. Hope to see more people adding models in the future as online geometry charts can usually be copy-pasted directly into their template with no fuss.

[Mark McM]

Originally Posted by cmg

Higher trailer=stable= bike wants to go in a straight line= can let go of bars as long as your going straight= not twitchy = slower steering , more input from rider to turn.

Lower trail= faster steering= rider needs to pay attention= can let go of bars but the bike may turn = twitchier steering. if the steerer tube were 90 degrees to the ground the trail would be zero and the bike would be very difficult to ride, any input could change steering.

Not quite true. Higher trail is more stable at higher speeds, and is easier to ride no handed, but that doesn't mean you can't still turn when riding no handed. Higher trail just requires more body English to turn when no handed.

At very low speeds (as often used when picking your way through a rock garden), trail makes it harder to stabilize the bike, largely due to flop. Even on the road, very high trail may make bike less stable at low speeds. For example, riding a high trail bike up a steep hill out of the saddle can be unstable, as the flop tends to make the bike want to weave with every rock of the bike.