Rake/Trail Question

[Rotor]

Can't get hy head around this one.

 

I am thinking of lowering my R12RT with Works Shocks. While doing a search on the topic I read from a poster that it would create "quicker steering". This would indicate that the rake/trail was affected. I understand changing the height on one end without the proper adjustment to the other would alter the steering dynamics; but, changing equal amounts on both ends???

 

I don't want to alter the handling of my bike. Any thoughts?

 

John

[David]

I don't know what that poster meant, but it will be quicker steering if the bike is lowered while maintaining the rake/trail. Picture a bike at 20 degrees of lean in a left turn, and then 20 degrees of lean in a right turn. To transition from one attitude to the other, the top of the bike must travel a greater distance if it's taller, meaning the same force in "flopping" the bike from side to side will create a "slower" turning bike if it's taller.

 

But that's Geek-land, and in the real world, I think you'd be hard pressed to notice the difference. In other words, don't let that be a factor. Much more important when considering lowering a bike is cornering clearance.

[T__]

John, lowering your bike (evenly front & rear) won’t change the rake but can alter the trail slightly & will shorten the wheel base slightly (don’t know how much as the BMW uses a front lower control arm) as the front forks are at an angle so bring the front wheel rearward as they compress.. Lowering can also lower the bike’s center of gravity..

 

Will it grossly effect your bike’s turn in & handling? I seriously doubt it but without actually riding the before & after no way to know the effect for sure..

 

 

 

Twisty

 

[Rotor]

David / Twisty,

 

Thanks. I'm getting the picture. Appears to be more about reduction in the degree of lean angle (height and CoG) than the actual steering geometry. On-the-other-hand, I also see how the trail could be shortened. Kinda like the way compressing the front shocks momentarily and slightly changes the wheel base. I do, however, really like the handling performance of the bike in stock form - minus the shocks - and don't want to adversely change that. Just want more of my feet on the ground; and, while I'm at it, better performance out of the suspension.

 

Sounds like it's not that big a deal.

 

I appreciate your time and info.

[Mister Tee]

Setting the front suspension slightly lower than the rear is a common trick that racers use to achieve a quicker turn-in. On the other hand, that's with a standard front suspension. It appears to me that the BMW paralever front suspension is a different geometry all together, so the same trick may not have such a pronounced effect.