Fat Bikes Fat Wheels and Tires Thread

[Slim]

We had a very icy ride with the family Sunday. I was glad I had replaced the worn studs in my 10 year old’s bike, and my wife and my 13 year old each had a brand new, super aggressive studded front tire.

At the moment our fatbikes are wearing (all 26”):

1. Mine: 90mm rims. Front 4.8” Bud, studded (~300 gripstuds) and tubeless (even though it’s not meant for that. Rear (4.6) Dillinger 5 studded Tubeless.
   
2. My 13 yeor old‘s OG Blackborrow: 80mm front rim with Johny 5 studded, tubeless. 100mm rim tubeless (even though it’s not meant for that), with Wazia 4.6 studded. Replaced some of the stock studs with their Triple point aggressive stud.
   
3. My wife’s OG Beargrease: 80mm rims. Not tubeless. Front 4.6 Wrathchild studded. Rear 4.6 Dillinger 5 studded.
   
   
   
   
4. my 10 year old’s 9zero7 bike: front 65mm rim, Escalator studded, rear 100mm rim, Dillinger 4 studded (neither tubeless).

 

[Tom K.]

Just say no to 60tpi.

Fatbike tires I really want thin and supple casings (for winter use). Often they are run at such low pressures, that the casing is deforming a lot. I have to think a more supple casing with have much less rolling resistance in that scenario.

My thoughts exactly, then Old Sage Mike Curiak told me he runs 60 tpi, rear especially, for deep snow. He says that due to low pressure, the expensive 120 tpi casings actually wear out from wrinkling, and he's too cheap to replace pure snow tires every year.

I'm learning a lot.

@Tom K. , I know the specs for the Beargrease say Max 27.5x4.0 on 82mm rim.

Since your rim is only 70mm, you can probaby fit “4.6” inch tires on there in back on that rim. How much room do you have around the D4?

Just got the new rear DT/Nextie mounted. You are right. On the 70 mm rims, I could definitely fit a D5......but I own two new studded D4s, and they are going on 80 mm rims, so I'm OK.

Now, everybody sit down. With an actual scale, my wheel swap and tubeless conversion (including sealant) SAVED ME 4.5 POUNDS!!!

Lighter wheels, no more tubes, and a switch from NX Eagle to XX1 Eagle cassette. Neither Mike or I realized that the NX cassette uses a Shimano-esque driver. He sent it with a regular Eagle driver, so I pirated the cassette off the Top Fuel for now, and my LBS is sending me a new X01 for it.

Stoked. Can't wait to take it out for the maiden voyage. Probably Wednesday.

 

[Slim]

I still go for 120 tip rear. Unlike MikeC, I don’t (normally) ride in super deep, soft soft snow. A few times a winter in a few inches, not feet deep puff like him.
The other thing is the amount he rides, vs how much I ride.
I do sometimes wrinkle the sidewalls, but most of the time it’s mild bulging. Definitely more than on my MTB, that’s true.

I do see the telltale diagonal fabric lines on the sidewalls, but even the Bud, which is my oldest tire(7 years old?) is still holding up.

 

[Ron]

My thoughts exactly, then Old Sage Mike Curiak told me he runs 60 tpi, rear especially, for deep snow. He says that due to low pressure, the expensive 120 tpi casings actually wear out from wrinkling, and he's too cheap to replace pure snow tires every year.

this makes a lot of sense but Gnarwhals only come in 120tpi and thats what he said he ran for deep snow...... I do notice that with the Gnar's you dont need to run them as low as the Brabagazi's to get solid traction. I think next ride (in fresh snow) I will try 1.5

 

[Tom K.]

Wow, just wow!

The DT/Nexties, plus tubeless, plus a much lighter cassette lopped 4.5 pounds off the Beargrease. Less effort, more speed, more fun!

 

[Superbman]

We had a very icy ride with the family Sunday. I was glad I had replaced the worn studs in my 10 year old’s bike, and my wife and my 13 year old each had a brand new, super aggressive studded front tire.

At the moment our fatbikes are wearing (all 26”):

1. Mine: 90mm rims. Front 4.8” Bud, studded (~300 gripstuds) and tubeless (even though it’s not meant for that. Rear (4.6) Dillinger 5 studded Tubeless. View attachment 116435
2. My 13 yeor old‘s OG Blackborrow: 80mm front rim with Johny 5 studded, tubeless. 100mm rim tubeless (even though it’s not meant for that), with Wazia 4.6 studded. Replaced some of the stock studs with their Triple point aggressive stud. View attachment 116436
3. My wife’s OG Beargrease: 80mm rims. Not tubeless. Front 4.6 Wrathchild studded. Rear 4.6 Dillinger 5 studded. View attachment 116437
   
   
4. my 10 year old’s 9zero7 bike: front 65mm rim, Escalator studded, rear 100mm rim, Dillinger 4 studded (neither tubeless).

FWIW: Bud/ LOu grip studded are absolutely gold---there's a large crew of us in western ma that have been rocking those 4.8 monsters with carbide studs for a long time---other than weight, I prefer them vastly to the wrathchilds. Great tires for ungroomed snow/ ice/ semi-frozen mud (with or without studs).

 

[Tom K.]

Well, THESE look pretty special.

HED, Berd & Onyx team up to create super light carbon fat bike wheels for a limited time

Quick, what’s the most Minnesotan wheel you can think of? That’s probably not something you’ve given much though to, up to this point. But being…

bikerumor.com

Could easily be made even lighter with a different hub choice, though replacing the Onyx hubs would kill the "all Minnesota" goal.

 

[Ron]

that's pretty much What Im running now but a I9 Hydro. 1820 for a set.

Industry Nine - Big Rig 825c 32h

industrynine.com

 

[Tom K.]

@Ron you did the Berd spokes? Very curious about them.

FWIW the link you posted leads to a page that says this wheelset has been discontinued?

 

[Ron]

yeah, they dont make that model any longer, I think they make these special models every so often. I cant say much about the spokes. I didn't pay attention to them when I bought the bike. the wheel set was part of the build out. the wheels are crazy light.

 

[Tom K.]

Got the new Wampa wheels up and running with studded D4s. The timing on moving to studs couldn't have been better. My first fling with studs, and they have been awesome on two refrozen rides.

The wheels are also impressive. Not quite as light as the Nextie/DTs, but much sturdier, with a full double-wall rim construction. I'm thinking that the studs will end up on the Nexties and the unstudded D4s on the Wampas, but it will take a spell of "inside" weather to motivate me to switch over two sets of tubeless tires/wheels!

 

[Ron]

I should be riding today. Im in quarantine but I can ride and not come close to anyone on the trails been me. I am torn on which tires to ride today but thinking I'll stick with the Gnar's since we got about 2 feet this week including about 4" yesterday.

 

[Ron]

@Tom K. where did you end up on PSI's? I am still playing around, My tires seem to hold air well but when I inflate in the garage to ~2.0 psi , at 60* (heated) by the time they get in the snow, I feel they are too low. I showed that after riding 5-6 miles, I am sitting at ~1psi. I wonder if a little more air would help with CRR. Thoughts?

 

[Tom K.]

@Tom K. where did you end up on PSI's? I am still playing around, My tires seem to hold air well but when I inflate in the garage to ~2.0 psi , at 60* (heated) by the time they get in the snow, I feel they are too low. I showed that after riding 5-6 miles, I am sitting at ~1psi. I wonder if a little more air would help with CRR. Thoughts?

I'm much higher than that, but I've been riding almost no real snow. So, for mixed dirt and hard pack snow, I'll run 7r/5.5f. The few times I've had real snow 6r/5f seemed ok (remember I'm 195 pounds).

In any event, I've found this chart helpful:

 

[Ron]

YEP! I looked but couldn't find a chart like this. seems to correlate well, I need to up my PSI to 3-3.5. I am going out shortly and will report. I like lower PSI on trails with a base of soft snow, once the flex in the sidewalls is gone, the tire doesnt spin as well. I think it needs to deform to grip and roll better.

 

[Ron]

I rode today, put 3psi in the tires at 60 degrees, outside was 30 with light snow. Its hard to say because the trails were so loose but I think that was about right, I let some air out which only helped slightly on the loose snow so I dont think theres a significant gain with having 2psi vs 1 psi on loose unsettled snow.

 

[Tom K.]

@Ron, A great read on fat bike tire pressure by the Sage of Fat Biking himself:

Fat tire pressures for snow.

A good friend of mine recently got the fatbike bug, largely so that he could ride on snow, and wanted to better understand appropriate tire...

lacemine29.blogspot.com

 

[Ron]

I like this quote. I am going email Mike. The issue is riding here is rarely flat. The sections that are relatively flat <6%, are no problem, the issues are everything else . I am going to put back on my Barbi's and ride the hardpacked groomed main access road until they start grooming the single track . I am also going to try moving my seat back a bit so help keep more weight over the back tire, obviously, as soon as the rear tire starts to slip, your done on the steeper climbs.


"As temperatures and conditions change the appropriate pressure for the surface can fluctuate pretty dramatically. 1psi makes a big difference. My way of staying safe (avoiding flats or rim damage) is to lean all my body weight on the saddle, while looking down at the rear tire. Any wrinkles in the sidewall? Add psi until the wrinkles go away. That's your baseline for hardpack. The flipside of that process is that for the softest, least-packed snow (the kind where you should have chosen to ride lifts with skis on that day!) you can go as low as four or five wrinkles in the sidewall as long as you're being delicate. More than five wrinkles and you're generally just adding resistance without increasing float or traction. That said, conditions in my neck of the woods often require 5+ wrinkles just to keep pedaling, and since pedaling beats walking..."

 

[Ron]

So I put back on my Barbagazi's and rode on snow that has been compacted more than the other day (was fresh and loose). The trails were still frozen and fairly firm. I wanted to try them at a highly higher PSI than I typically ride, ~1spi. At 3, they were great on the groomed hardpacked (but soft) snow but once on the single track with frozen footprints and prior tire tracks, they felt too bouncy and grabby on the troughs of the re-freeze) , I lowered to 2 F/R and that was fine on relatively flat trails and moderate climbs<6%, but too much once I got on steeper pitches >6% and on the corners of switchbacks with loose & unsettled snow on the outside and inside of the trails. I lowered to 1.75 R, 1.5 Front. This felt better yet with more traction. I was getting some auto-steering effects on the front but I think most of it was due to riding over re-frozen snow and the foot prints and prior tire tracks were grabbing the front tire., I dont think theres a way to get around that. After riding a few miles on single track, I popped back out on the main groomed road (its a smooth fire road that is groomed for hiking, biking skiing and sledding. you can hike up 2miles with 1K vertical) And climbed the last 1/2 mile which is fairly steep maintaining about 8-10% and the tires gripped and rolled as if on dirt.

I will continue to play around with PSI but Im feeling pretty good with these PSI's, I might go back to the Gnarwhals occasionally for more loose snow riding as needed.

I'm open to suggestions on handling frozen tire tracks and such that grab and channel your tires.

 

[Tom K.]

I'm open to suggestions on handling frozen tire tracks and such that grab and channel your tires.

Twice weekly dumbell/situp/core/pushup routine?

Are you pretty much on "all snow" at those low pressures?

We are not quite there yet, and if I went down to 2 psi, I'd be buying new rims.