"Weight on the wheels" - geometry discussion

[ctwo]

Have you done this experiment with two identical scales? How much weight shifts to the front wheel by raising the rear 1/4 inch?

Let's assume 500lb bike with 50/50 balance, 6' wheel span. I'd guess

0.00", 250-F, 250-R
0.25", 251.1-F, 248.9-R
1.25", 255.5-F, 244.5-R
2.25", 259.9-F, 240.1-R
3.25", 264.4-F, 235.6-R

 

[afm199]

say your bike is kitted-out with every piece of data acquisition possible - suspension position, tire temp, IMU, strain gauges, etc. say you also pay a ridiculous amount of $$ to hire the best engineers in the world and to use the best pieces of software. do now have enough data, knowledge, and capabilities to fix or optimize every possible riding issue without guess and check? nope.

the problem is still indeterminate. you'll be able to optimize the majority of riding situations, but not all. you could probably input your bike, riding style, and track into a simulator and get a pretty damn good solution. but it won't be perfect.

how do I know? cuz MotoGP cant get it perfect. they show up to known track with a known bike on known tires with a known rider and still screw things up. sometimes they miss the setup so bad they go slower than previous years or previous tests.

This. One of MotoAmerica's suspension gurus told me this: "More than half of my job is to get the rider's spirits up, remind them that they are talented and fast, and not to change anything."

 

[bobl]

An old story about Pops Yoshimura tuning for (I think) Eddie Lawson. After lots of changed to the chassis, the lap times stayed the same. It finally dawned, the rider was compensating for whatever was done. Instead he asked "what would make you more comfortable", and the laps times dropped. Ain't no magic bullet. I remember running up behind a kid on a new R6 on one of our more crappy roads, and seeing daylight under his wheel when hitting bumps. At the next stop, I mentioned that I thought (ok, I knew) his set up was too stiff. He told me that it was right because he had it set up by of guy at the track. I just said Oh.

 

[TWF]

Oh yeah, I am not doubting that it greatly affects handling. Even raising the fork tubes by 3mm produces a noticeable change in handling such as quicker steering.


So we can agree that "puts more weight on the front wheel" and equivalent phrases are complete bogus?

Yea they are bogus.
What changes is how load is transferred

 

[Jalopyshoppe]

Yea they are bogus.
What changes is how load is transferred

Zoran, I miss you.

 

[kuksul08]

Yea they are bogus.
What changes is how load is transferred

Zoran, I miss you.

I miss you too.