Mountain Bike Reviews Forum banner
1 - 14 of 14 Posts

·
Registered
Joined
·
40 Posts
Discussion Starter · #1 ·
So this is a multi part question. I’m running a Specialized Helga which was designed around 26x4.6 tires. I have two 26 fat wheelsets with 90mm rims and I was running 4.8 Minions one set and 4.0 Jumbo Jim’s on the other. What I found was that the BB height was lowered too much and the handling was much less stable for me to be comfortable running then on singletrack. I like the strength of my 26 inch wheels and the cushion and rollover of the 4.8 tires. I’m 360lbs and this combo finally feels like to me I can finally ride aggressive and technical features without fear of breaking my bike.

I always hear about changing to 27/29+ for riding singletrack and I know 27.5+ would drop my Bb to low and 29+ I’d be weary of excessive rim flex, so I’m wondering if 27.5 Fat would be a good compromise? If I were to go that route my rim choices would be limited to either 50mm or 80mm Mulefuts, which I think would be on the extremes imo for running 27.5x4.0. If I had to pick one I’d pick the 80s cause they are closer in style to the rims that I’m currently running.

The other variable would be tires. I ride in a mix of conditions from hardpack to loose/damp and rocky. I like the Minions but the 3.8 versions seem to not have a lot of rim protection. The other option that I was considering we’re the 4.0 Vanhelgas in 60tpi. They are supposed to be tall for a 4.0 tire, and I think based on the room that I have around the 26x4.8s, the 4.0s should only be a tad taller which would help with BB height. Also I specified the 60tpi tires because based on my weight and satisfaction with the EXO sidewalls of the Minions, I’d think that the 60tpi tires would be more durable than the 120tpi tires.

I want feedback regarding tire/rim options. As or right now I plan on sticking with 4.6/4.8 tires because I like the way they handle with the way my bike is set up, however I am genuinely curious if I could benefit from going to 27.5 fat and what my options are.
 

·
This place needs an enema
Joined
·
17,236 Posts
If we were discussing regular trail bikes, 29" would have a disadvantage for you/your weight because the hubs are narrow.

On a fatbike, with suuuuuper wide hubs, this concern gets thrown out the window. You could easily and safely run 29" wheel of any width (2.5" to 3") tires on your bike and it'd be fine.

80mm rims with 4" tires are really, really prone to damage from roots, rocks, etc... as the tire just can't protect the edge of the rim very well. For snow this combo is fine. For dirt it helps to go narrower on the rims.

At your weight I'd look at a ~70mm rim coupled with a 4" tire. Like the Lithic Rhyolite.

I run 26 x 5" tires for soft snow, 27.5 x 4.5" for firm snow or soft sand, 27.5 x 4" for packed sand (washes, arroyos, etc...) and 29 x 2.8" for singletrack trails.
 

·
Registered
Joined
·
1,679 Posts
Oh. My. Thank. You.

I spent the past 3 days trying to find 65-70mm alloy rims in 27.5. I have no idea how I couldn't find these rims. I'm probably gonna snatch them up if I can.
I have been very happy with my Lithic Rhyolite rims! Granted, I am much much smaller than you AND I am using the 26" version, but I would strongly consider using the 27.5" version if/when I decide I need 3 wheelsets for my pugsley.

I built mine with straight pull spokes, offset, and it was a very easy wheel to build. Even given the weirdness of it.
 

·
turtles make me hot
Joined
·
11,706 Posts
I've been building the 26" version of those wheels, the Alex Blizzerk quite a bit lately. Mostly with Surly Ednas. Fantastic rims. I want to do a set of the 27.5 Lithics for myself.
 

·
Registered
Joined
·
107 Posts
I recently picked up a 27.5 wheelset with 80mm rims and 3.8 Minions on them. The diameter is very close than my 26 wheels with 4.4 JJs. So if bottom bracket height is your biggest concern, a cheaper fix might be some larger JJs. I'm not a fan of the Minions, but I've just set them up tubeless so I'm still giving them a chance.
 

·
Registered
Joined
·
40 Posts
Discussion Starter · #8 ·
Given your proposed use, I am at a loss as to why you're not installing 29+ wheels and tires.
Tire pressure and rim flex. I think it was said that running 29+ rims on wide spaced fat bike hubs mitigates the flex but I'm not sure if that's what was meant. The second thing is that I feel like at my weight with my rigid bike I would be running tire pressures in the 20-30psi range on a 3.0 tire whereas with a 4.0 I could run lower. For me 27.5 fat feels like a good compromise between the cushion of the 26x4.8 -

Actually now that I'm remembering, it was because I liked running 26x 4.0 tires but I didn't like how they dropped my BB height.
 

·
Registered
Joined
·
40 Posts
Discussion Starter · #9 ·
I recently picked up a 27.5 wheelset with 80mm rims and 3.8 Minions on them. The diameter is very close than my 26 wheels with 4.4 JJs. So if bottom bracket height is your biggest concern, a cheaper fix might be some larger JJs. I'm not a fan of the Minions, but I've just set them up tubeless so I'm still giving them a chance.
I got the Jumbo Jims used for reeeally cheap just to try out. I wouldn't really want to run Jumbo Jims on trails just due the the smaller size of the knobs. I went back to my 4.6 Ground Controls and I think I'd be comfortable running them for the time being.
 

·
Registered
Joined
·
40 Posts
Discussion Starter · #10 ·
So just in case anyone was still following with this I wanted to update:

I did end up going the 29+ route and over the past week I've been getting parts together & I got my wheels re-built. I went with Sun Ringle Mulefut 50s (Non-SL, hopefully they're stronger than the SL model) and I'm running 3.0 Minion DHF/DHR II tires, which I didn't know existed until I considered going 29+

Bicycle tire Bicycle wheel rim Automotive tire Bicycle wheel Bicycle part


I got the wheels on my bike and it basically maxes out my rear tire clearance, and I did some short street riding. The tires rolled well and I only experienced some flex when hitting a short 1 1/2' drop. What I will say is that going to a narrower 29+ tire I definitely don't feel as much tire compression when riding down steps. I haven't had a lot of riding time on the new wheels but I was definitely surprised with how they felt when riding them. Looking forward to seeing how they handle trails.

Bicycle tire Tire Bicycle wheel Wheel Bicycle wheel rim


Bicycle tire Bicycle wheel rim Automotive tire Bicycle accessory Bicycle part


Bicycle tire Bicycle wheel rim Bicycle wheel Bicycle frame Bicycle part


Iron Metal Rust Steel
 

·
Registered
Joined
·
780 Posts
At your weight I'd look at a ~70mm rim coupled with a 4" tire. Like the Lithic Rhyolite.

I run 26 x 5" tires for soft snow, 27.5 x 4.5" for firm snow or soft sand, 27.5 x 4" for packed sand (washes, arroyos, etc...) and 29 x 2.8" for singletrack trails.
Very happy to find this recomendation. Been considering the merits of 27.5 fat for summer riding and miniaml snow riding (Kansas City). I like the ryholite but was wondering how it hold up to big dudes and if the 4.5 cake eater would be too much tire. Sounds like it may be a great setup for me.

I currently run an 80mm mulefut 26er with jumbo jims. Wondering if 27.5 cake eaters would be worth the upgrde.
 

·
Registered
Joined
·
1,679 Posts
.. I like the ryholite but was wondering how it hold up to big dudes ... I currently run an 80mm mulefut 26er.
I have experience with both rims, but primarily in the 26" flavor. Also, I do think this speaks to the strengths/weakness of the rims, but I have experience with both rims built into the offset 17.5mm Pugsley configuration. The mulefut, while it built with nearly even tension so in theory would have been a great wheel, was flexy as hell when built offset, so much that I did one lap around my yard and unbuilt it. The Lithic Rhyolite, has been rock solid, and it had a more unbalanced tension in the build. It is a solid rim and eventually I'll get the 27.5" variant of it.

So, while I'm not a bigger guy (160 on a heavy day), I do put the Pugsley through its paces towing my daughter around on blue/green trails and the trailer/her weight is 60+ pounds. I would only build a mulefut again if I was able to do a traditional (non-offset) build, but even then I suspect that the Lithic is still the stronger rim.
 
1 - 14 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top