Tyre pressure on Fluid2


(Jim Boone) #1

Hi all, just a query on what you guys do for tyre pressure on the F2, I can set my roadbike ok on it so it spins without slipping, but I have to swap it out for my daughters MTB frankenbike with a 700c wheel and 28mm tyre. With it at 80psi (max 85) I cant lock it out in the upright position without it deforming the tyre a lot, and then there is lots of rolling resistance, she is struggling a bit anyway so thats a bit mean :wink: I backed it off 1/4 but it fell off as it wasnt locked out, I need to be able to swap bikes easily as that makes it practical etc, any of you have a similar problem and fine that lowering tyre pressure allows you to lock it out without undue resistance? Yeah I know I should try it, but my time is limited for experimentation etc and you guys have probably had similar issues :wink:


(Eric C. (Zwift HQ)) #2

You should have it set to 100psi for maximum accuracy.


(Jim Boone) #3

Ok, but that doesnt make any sense :wink: I could fit a thinner tyre that is rated at 100psi, and its worth a try, I chose 28mm because I wanted to see the effect of a bigger contact area. The issue, at least on this 28mm is that the Fluid 2 uses an over center cam action to lock it (I’ve waited 25 years to use that phrase in anger lol) and it needs to lock at 12 oclock, otherwise due to the angle of the plate it locks against, it doesnt lock over properly. But, it either gives me very light contact, which 100 psi wont help with as I don’t think the OD will increase much, or I get a lot of deformation in the sidewall and hence increased rolling resistance. The issue is, with the amount of engagement that 1 full turn of the adjuster creates. Please understand Eric, this isnt a question of how it should be run, its a question of how you have to adapt it to run given a mismatch of OD and thread position on the adjuster, what it reall needs is face plate that adjust for angle so you can lockout in any position, or very veine threads on the adjuster so 1 turn is less of a distance, I was really just curious if any other fluid 2 users had the same issue. I have a 23mm tyre I can try instead, it will probably go the other way :wink: in which case she can have my front 25mm tyre :wink:


(D W - ltb LMDGD) #4

I have a couple of Fluid 2’s with the older yellow mechanism that can lock at 6 and 12 o’clock. If I were forced to only use full turns, I’d use tire pressure to compensate. I used to ride my mountain bike with knobby tires on one all the time (wow, it’s crazy loud) and used slightly lower tire pressure and the tire never seemed to slip but I had the option of half turns. Another option is to source the newer knob which offers unlimited adjustment (which I also have) but then it isn’t as quick to swap bikes. I’m not sure on this one but another option would be to leave the latch in the open position and tighten which would then offer the fine adjustment of the newer knob mechanism.


(Jim Boone) #5

Hi Walter, thats a pretty good idea, to tighten up without the cam etc. I’ll double check but mine doesnt seem to lock out at 6, maybe the angle its at. Either way if I can do it with just tightening down, I might even see if there is a big wingnut to replace it. I didnt want to mess with it, just unlatch one bike and swap, but, if I have to adjust it, I may as well bite the bullet and spin a wingnut!