RockShox Super Deluxe Coil Select+

[Marzio]

Hello all,
I bought my Santa Cruz Bullit M size with spring 450 M. this spring is suggested for riders around 82 kg weight and I'm 67 kg.
it's my first experience with coil rear suspensions, but what for me is strange is that even with a spring for heavier people than me and sag of 25% (the suggested sag from SC is 28 - 32 %) even without big jumps my shock is always at end stroke.
Is it normal? do you advise anyway to change the spring, maybe for a spring rate of 400 lbs?

 

[BullitMan]

Are you saying you're bottoming out all the time?

 

[Marzio]

Are you saying you're bottoming out all the time?

I would say not all the time, but every time I ride the bike the bottom out bumper is always at the bottom even without jumping or big bumps.
with air shocks the o-ring wasn't always the bottom, so I was wondering if with coil shocks the behavior is different, especially because I'm using a spring rate for people 15kg heavier than me

 

[steve_sordy]

Coil shocks have a constant spring rate. Can you obtain a coil spring with a progressive spring rate? I know they are made because I have seen adverts for them. I assume that they make them out of wire that has varying thickness, but I can't be sure. This would mimic the ability of air shocks to be ramped up by adding spacers to reduce the air volume.

I have never ridden a bike with a coil shock.

 

[Marzio]

Can you obtain a coil spring with a progressive spring rate?

no idea, first time I hear about a coil spring with a progressive spring rate. I will investigate...
thanks

 

[Planemo]

Can get progressive springs but that still doesn't answer why the OP is bottoming out on a constant rate spring designed for more weight. Could be something as simple as the spring actually not being the poundage rating quoted? (an error on stated poundage?) Or maybe the Santa Cruz linkage design adds progression during travel?

Progressive springs use the same wire diameter throughout, they just have variable distance between the coils. A closer distance increases the amount of coils therefore increasing the available amount of metal to flex and by default reduces poundage. Which is why if you cut a constant rate spring, it lowers the vehicle but massively ups the poundage because you have removed some available flex over the length.

 

[Marzio]

Can get progressive springs but that still doesn't answer why the OP is bottoming out on a constant rate spring designed for more weight. Could be something as simple as the spring actually not being the poundage rating quoted? (an error on stated poundage?) Or maybe the Santa Cruz linkage design adds progression during travel?

good questions, I will check with Santa Cruz, I'm curious about their answer!