[ShortTravelMag]

Finally threw a 100mm bluto on my bike after buying it 2 years ago. I like the extra cushion up front, although I've only ridden with it using my 29x2.2 wheels/tires. So it's a hardtail mtb at this point, not a fat bike.

Anyway, now that it's colder, I'm finding my travel has gone down a bit. I have the lockout on it, and it's not much different now with or without it because I'm guessing here, the coldness has sucked up some of the travel? I don't know how to word it exactly.

Is it the oil? Should I simply lower my air pressure down to get back some movement? It's okay now, coldest I've ridden is low 40s, locked out I get about 20mm tops blowoff, and unlocked I can get 40mm or so without slamming anything.

Just curious if there's a concensus on cold weather and suspension forks...lower air? different oil? Throw it on the bench and put the rigid back on?

 

[Jayem]

Whatever you are describing is hard to understand.

I wouldn't recommend using a lockout unless you are on a totally flat paved road, and even then only if you really have to, like pedaling wildly uphill. In many cases, lockouts put extra stress on the shock, requiring the seals to hold higher pressure.

But that said, the lockout should usually be pretty firm, if you aren't finding a difference between lockout on and lockout off, it's usually the result of air getting into a sealed damping cartridge. A bleed can bring it back, but a seal-change is probably in order longer-term.

If your fork is sucking down, that's usually a negative spring problem. Some you have to pull up really hard to equalize the negative spring, like step on the wheel, pull up on the fork brake arch really hard, you'll hear a little hiss at top of travel as the chambers equalize, then you'll be back to full travel. This can happen when letting out air on some forks. Every once and a while grease can block the negative spring equaling port, but that's rare.

If you are not getting full travel no matter how low you set the pressure, that could be due to oil having leaked out into the bottom of the fork, the fork hydro-locking or partially hydro-locking.

40 degrees should be no problem for any fork.

 

[ShortTravelMag]

It’s not leaking, it’s 100% fine. The lockout rules as I spend 90% of my miles on paved bike paths. Every rockshox I’ve had has a little blowoff travel when locked out. My sid with hydro lockouts even lets me set how much blowoff travel. I use the lockout constantly when hammering miles out on bike paths. In lock when I need to hit a curb or something

that’s not the issue. Certainly I’m not nuts to assume 40 degree temps might change the fork behavior, no? You mean an air fork with oil damper works exactly the same at 80f as 40?
I’ve only ridden a rigid fat fork during colder weather. So suspension in cooler temps is kind of new for me.
The fork is working just fine, it’s a month old to boot, in ride time.

 

[Jayem]

It’s not leaking, it’s 100% fine. The lockout rules as I spend 90% of my miles on paved bike paths. Every rockshox I’ve had has a little blowoff travel when locked out. My sid with hydro lockouts even lets me set how much blowoff travel. I use the lockout constantly when hammering miles out on bike paths. In lock when I need to hit a curb or something

that’s not the issue. Certainly I’m not nuts to assume 40 degree temps might change the fork behavior, no? You mean an air fork with oil damper works exactly the same at 80f as 40?
I’ve only ridden a rigid fat fork during colder weather. So suspension in cooler temps is kind of new for me.
The fork is working just fine, it’s a month old to boot, in ride time.

They don't work dramatically different 40 degrees IME. Suspension shims controlling high speed compression and rebound don't really care much about the viscosity of the fluid, fixed orifices like low-speed adjusters do, but most forks have high speed damping, even if it's not adjustable externally. IME, the amount you might have to adjust a fork for temperature is pretty damn small, like 2 clicks. Your air spring might be significantly different and need to be adjusted, but that's a different matter. I mean, you drive your car in 40 and 80 degrees, right?

What do you mean you are missing travel?

Is this a motion-control fork? In my experience, they tend to leak out the bottom and when they start doing that, the lockout stops being effective.

 

[TavisB]

I'm really confused by this. I've never noticed any difference in my Bluto with temperature.

Sent from my Pixel 6 Pro using Tapatalk

 

[pelts79]

My Bluto got very sluggish in the cold.

 

[BansheeRune]

Finally threw a 100mm bluto on my bike after buying it 2 years ago. I like the extra cushion up front, although I've only ridden with it using my 29x2.2 wheels/tires. So it's a hardtail mtb at this point, not a fat bike.

Anyway, now that it's colder, I'm finding my travel has gone down a bit. I have the lockout on it, and it's not much different now with or without it because I'm guessing here, the coldness has sucked up some of the travel? I don't know how to word it exactly.

Is it the oil? Should I simply lower my air pressure down to get back some movement? It's okay now, coldest I've ridden is low 40s, locked out I get about 20mm tops blowoff, and unlocked I can get 40mm or so without slamming anything.

Just curious if there's a concensus on cold weather and suspension forks...lower air? different oil? Throw it on the bench and put the rigid back on?

If you are at 50°, there will be little to no perceivable change. Get down around 0° and you will have 15w30 in there, below zero and that becomes 85w90. Slow on both compression and rebound, if there is any activity at all. Exaggerating on oil weights but gives an example. Lockouts are meh. Something that I don't actually use it cause I am far too lazy.

 

[ShortTravelMag]

I use my fat bike as a gravel bike, have the narrowest Q factor possible I think, 177mm which is only 9mm more than my xc race bike.

I tried rigid and just couldn’t get in. I need some cushion. A lauf would probably be perfect as I do not ride off road in this configuration. When the races start in 3 weeks, I’ll put the rigid fork and 26x4 wheels back on.
I already the bluto laying around, and it changed the whole bike.

the first race is at a real mtb trail, lots of rocks and giant roots, so I’m going to try the bluto just for that one race. The 2nd race is at Trek factory headquarters and is much smoother, basically the cyclocross course. So rigid again.

I’ll drop a few psi and see if I can get back a bit more travel.

 

[ShortTravelMag]

 

[Brad Pitted]

I experienced similar when my bluto was new. Upgrading the seals, ensuring proper oil level and plenty of slick honey made a big improvement. That said, there is no substitute for a mastodon if you can get past the weight.

 

[ShortTravelMag]

No need for Mastodon though, again, not really used off road, just to help soften the 29x2.2" Thunder Burt tires. I hated fully rigid, even on bike paths and gravel bike environments. I'd be a perfect candidate for a Lauf, but they are way overpriced now that they went consumer-direct. You'd think the exact same design from a decade ago would maybe come down in price a little, usually does when a company does not make even minor changes (Lauf 2.0). But that's another story.

I let more air out and it's a bit better. Good enough at least. In the spring, when the bike will likely get hung up for the summer, I'll do a fork overhaul 50-hour that always makes my SID feel like new. Same fork basically, so I know the procedure well and have all the spare parts.

One thing I've yet to do is ride the Bluto with the actual fat tires. I'm going to do that this week, and see if I really need the fork at all. A few back to back rides through a mild trail, the type that the races are often run on, should help me decide.

 

[prj71]

Bluto winter kit

Get your Bluto winter ready with this kit ! Kit includes: S4 2.5 Wt Hydrauflow oil (For cold weather) S4 Low friction grease S4 custom winter seals S4 Plantimum 20 Wt fluid Easy to follow instructions sheet Want to change your dust wipers while you're at it ? Click here

s4suspension.com

Shockspital Bluto Cold Weather Kit in Mar 2023 - OldGloryMTB.com

Cold weather kit for the RockShox Bluto fat bike fork.

oldglorymtb.com

Turnagain Cures Cold Weather Blues with new ETR Seal Kit for RockShox Bluto Fat Bike Forks

Having just finished our review on the RockShox Bluto suspension fork, Tim and I both agree that the fork is a good thing for fat bikes. Not so good though? The potential for issues when ridden below freezing. Officially, RockShox tells us that the fork will perform optimally from 0° C (32° F)...

bikerumor.com

 

[ShortTravelMag]

Interesting read, the original article and comments. I didn't even consider touching the rebound, I bet that would make it feel more like I'm used to. Thanks for those links.

 

[CaberGuy]

One thing I've yet to do is ride the Bluto with the actual fat tires. I'm going to do that this week, and see if I really need the fork at all. A few back to back rides through a mild trail, the type that the races are often run on, should help me decide.

Please post your results, curious to hear your thoughts!

 

[ShortTravelMag]

It's way too warm here in Chicagoland now! How am I to test this cold weather stuff when it's in the low 60's. Mentally, I already made peace with the 40's we had last week. But it says high of 39 on saturday, the day of my big long rides, so I'm going to test out the rebound adjustment and see what happens, with a bit less air pressure.

 

[CanmoreBruce]

I remember the early Blutos had a number of issues in the cold, so as mentioned the cold weather kit really helped. A few friends had them and they were basically non-functional once the mercury dropped. With the cold weather kit my kids Blutos seem to work fine until it starts getting stoooopid cold. Not sure how the seals/grease are in the more modern versions that come stock from RockShox.