It's a thing right? Not just me....
My poor bike has had snow on it since xmas eve. I put it in the workshop with snow on after a ride and it's still there when I get the bike out the next day or two later. I'm not sure we have had a + in the temperature at any time of the day since then either.....The suspension feels wooden - I'm guessing the oil thickens.
I've tried increasing the rebound but then doesn't really solve the problem. Reducing the pressure just seems to (obviously really) increase the sag but it's still slower then normal on the way down as well as on the way up.
Beyond bring the bike into the house to warm up before I ride it can anything be done? Or is it in my mind? Not a massive problem as the snowy riding in lockdown is not particularly hardcore, it just feels a bit odd.
Broader question - does car suspension change as it gets cold?
Rubber seals gets stiffer as they get colder beyond their design envelope. Damping oil becomes more viscous. Air springs, especially low pressure ones, get softer too. This will also affect negative air springs if present. Net result is as you're finding.
Cheers- forgot about the effect on the seals too.
Rigid fat bike (2nd hand) inbound so hopefully an irrelevance in a few days.
I’ve tried increasing the rebound but then doesn’t really solve the problem. Reducing the pressure just seems to (obviously really) increase the sag but it’s still slower then normal on the way down as well as on the way up.
You seem to have that backwards. You will need less rebound because the oil is more viscous. You should be setting the sag to the same level, which should require the same pressure at operational temperature. Setting more sag and increasing the rebound will make it feel wooden.
Yup, you need to wind damping off in order to compensate for the very low temp making the oil a bit stickier.
As for cars - yes, they do. The same effect will be seen in cars, motorbikes, all sorts. The difference is that a mountain bike weighs very little, has comparatively tiny dampers with tiny amounts of fluid in them.
A car is massive, has much more mass to overcome stiction, the dampers are bigger with more volume, there are heat sources all around the car that will warm them up quicker, and the effect will be much less noticeable.
I noticed this on a recent snowy ride. Charger 2.1 damper felt awful. Thankfully it's not sub zero all year!
You seem to have that backwards.
Sorry that's what I meant and what I did.
Setting more sag
I didn't beyond an around the drive 5second experiment.
As for cars – yes, they do. The same effect will be seen in cars, motorbikes, all sorts.
If you follow F1, you'll know that the Haas team have struggled with an unpredictable car. It often looks good in practice, but then sucks in the race, that sort of thing. One of the problems seems to be that the suspension dampers were getting hotter in the longer race stints than in the short qualifying and practice runs. That was causing the ride height to vary, which screwed up the aerodynamics, making the rear of the car unpredictable. An everyday road car will be much less sensitive, obviously, but big temperature changes would be measurable if you had decent instrumentation.
