Another topic has raised the question of chain growth on a VPP-equiped bike (Santa Cruz Blur, as it happens).

The other poster and I both experience a feeling like our chain rings are egg-shaped when in a low gear riding over bumps. Is this “chain growth” induced by the VPP system?

I have ridden half a dozen full sussers only and no other VPPs but I haven’t felt this on any of the others (four-bars, single pivots and whatever system a Whyte e-120 has!)

Guess its just me and you then….

Can’t say I’ve noticed anything. Surely any rear suspension will generate some variable chain length? Depends how much and in which gear it is designed to be minimised. Is it a BLT 1 or 2?

Swiftacular – some similar feedback from acjim just now here: http://www.singletrackworld.com/forum/topic/strong-short-travel-frame

It’s universal on the older VPPs isn’t it? I get the pedal feedback on my Nomad and have grown to love it. The first time I rode it up a climb I did think there was something wrong with the granny ring!

Ah, it was in the granny ring now i think about it.

I’ve always had a lot of granny ring pedal feedback from single pivots, but never on a four bar or VP design. Having said that, the only VP designs I’ve ridden are marin, so may not be that representative.

they will chain tug as the suspension design uses chain tension to stop the bob caused by our legs pumping up and down, youll notice it more on a vpp as you get chain growth in compresison and extension of the suspension from the ‘perfect sag point’ that is designed into them.