Stiff suspension on long, hard rides.

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Stiff suspension on long, hard rides.
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flag qduffy
O+
Posted: Apr 19, 2015 at 20:44 Quote
Figured I'd have some fun with the title - apologies in advance.

I have a Rocky Mountain Element BC Edition that has lately been suffering from progressively stiffer suspension on longer rides, especially with technical, bumpy downhills. I'm thinking it's heat related and that the suspension is stiffening up because of that heat buildup. 10 minutes into a descent and it's almost like riding a rigid bike as far as the small bumps are concerned. The shock doesn't feel particularly warm to the touch, but I'm not sure if that would a symptom or is the heat all contained inside?

For those of you that know the North Shore a bit I can get down 7th Secret followed immediately into about half of Expresso before the bike really seems to stiffen up.

- Fork Fox 32 Talas CTD 29er 95-120mm
- Shock Fox Float CTD
- I'm over 210lbs kitted out.

Am I now just over-riding the bike? I know it's more XC oriented and not as burly, but am I generally right in my assessment? Is my hot suspension making my bike hard?

Quinn
flag dmski
Posted: Apr 21, 2015 at 14:56 Quote
I'm guessing that the heat build up in the shock is making everything expand as heat tends to do. This could mean that your fluid is heating up as well which could make it expand and stiffen the ride. Even though it usually has the opposite effect and makes the ride softer and has less damping when the shock heats up, there could be something else going on. You could also have heat build up around the seals and holes where the fluid goes through making things have more friction. There could also be contaminants/metal shavings in the oil that starts to move around and plug the holes for the shock fluid to go through, making it loose its damping properties.

If I were you I would service your fork. Replace the fluid and check seals. If there is scaring/ scratches in the stanchions or lowers you may have had some wear and loose bushings. Are you bottoming out frequently or have you never bottomed out before? You could have too much air in the fork for your weight.

Maybe someone has more insight on this?
flag qduffy
O+
Posted: Apr 22, 2015 at 0:15 Quote
Thanks for the reply. I've never bottomed out either fork or shock - and I'm probably running a little more sag just to make things a tiny bit plusher... Or as plush as you can get on an xc bike.

I think a good service is a wise suggestion. Maybe just getting a lot more stiction and friction and heat. The fork was done back in November but the shock probably needs something soon.

It really feels as if the ctd levers on the fork and the shock were both switching from descent into climb - it's that dramatic a change. But everything is right where it should be.
flag dmski
Posted: Apr 22, 2015 at 7:41 Quote
I'm guessing it is a drastic change in pressure because something can't flow properly/maybe there is too much air in the fork for your weight. If you never bottom out, you may not be utilizing all of your travel and its too stiff for you. Set up sag around 15-20% of the stroke length when you are sitting on it.

There could be something going on with the shock getting rattled to lock out but that is not common. If both front and rear are doing it then its likely something else causing the problem.

Do fresh oil in the front and adjust the air in each. Put a zip tie on front fork stanchion and rear shock to see how much travel you are using up on a ride. You may already be set up properly. Also call up your LBS and see what they say.
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