Thursday, January 02, 2014

Tour bike geometry

As I'm getting into more touring, finding and maximizing a rig for long tours is an essential for my next years of cycling.   With that, I came across an interesting picture from Dave's blog from a ride in January '13, which I did on the (now-sold) Troll.

To me, the short wheelbase creates a situation where rack is rather far behind the bike's center of gravity. Way back there. This pic doesn't have panniers, but I can imagine a situation where you get loaded panniers too far behind the rest of the bike, and that is what contributed to the waggles I experienced when loaded touring on the Troll.

I am curious to check out the proportions of the frame/rack/panniers on Seafoam to see whether the mass sits a little closer to the bike's center. I think the Troll is a great multi-purpose bikepacking bike. For me, it just didn't work out as a loaded tourer.

I didn't have the best day on the bike from whence this pic came.


Pondero said...

I quickly read your post, and my initial reaction was, "yep, that sounds right". But then I thought that a short wheelbase MIGHT be shorter chainstays which MIGHT place the rear rack mounts farther forward and closer to the COG (somewhere around the navel maybe?).

So now I'm wondering if I'm missing something in your theory...or whether something else is going on with that waggle of yours.

Further thoughts on this???

Tim Smith said...

@Pondero, I think it's relative to the general size of the bike. Yes, shorter chainstays bring weight closer to center, but weight still dangling more behind center than on a long chainstay bike. Proportions or something.

That being said, it waggled and scared me and I'm happy for the Troll to have a new owner. It was a fun bike in a variety of situations, just not loaded. And I needed a loaded tourer.

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