Winter Racing - Tire Selection Advice / Across Varying Conditions

Jayem said:

I can't see the logic in going with another skinny tire for deeper/softer conditions. I would go for a D5 set and the set of D4s. Gnarwhals are nice because they have an aggressive tread, but that's not going to help you float and could be costing you rolling resistance. You don't need to go to go more aggressive than D5, I've experimented and you start losing rolling resistance advantages pretty fast and you don't want to be the guy out front anyway, that guy will expend a lot more watts. But a little more float is sometimes necessary and something like a D5 can make a big difference in a softer or more variable race without losing much rolling resistance, compared to a skinnier tire. It's kind of a pain to change tires, but I'd keep something like a D5 on most of the time, it's a mid-fat tire and good all around, then switch to the skinnier set if you have a race that is pretty much guaranteed on hardpack conditions only.

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@mikesee thanks for the info. Much appreciated.

@Jayem I had a similar thought in going with a wider set of tires - maybe even a D5 and Wrathchild combo? Both are 4.5" tires and would float better than the 4" D4. The mental block I run into is the D4's were SO good in the right conditions (groomed/packed). It was an all out sprint race/segment with studded tires - and they rolled great and provided so much grip. It was the most fun I've ever had on a fat bike.

But when it wasn't groomed/packed, they suffered. What do you think about a set of D5/D5 versus Wrathchild/D5's? I assume it's overkill as you alluded to. I think a Wrathchild front would be key in fresh snow, but the majority of the time, there will be tracks ahead of me (we've got a time slot to get the segment in), so plowing through fresh snow probably isn't all that likely. In that case, I might lean towards a D5/D5 combo. And then what about studs .. I'd be tempted to not put studs on the D5's, but they inspire so much confidence I think they're worth the weight penalty.

And agreed on switching tires being a PITA. My older set of D4's would not seat/hold air after awhile. I think they became blown out over time. I ended up having to run 10+ PSI just to keep from walking home on a segment run. Two sets of wheels are likely in my future.

ekraft84 said:

@mikesee thanks for the info. Much appreciated.

@Jayem I had a similar thought in going with a wider set of tires - maybe even a D5 and Wrathchild combo? Both are 4.5" tires and would float better than the 4" D4. The mental block I run into is the D4's were SO good in the right conditions (groomed/packed). It was an all out sprint race/segment with studded tires - and they rolled great and provided so much grip. It was the most fun I've ever had on a fat bike.

But when it wasn't groomed/packed, they suffered. What do you think about a set of D5/D5 versus Wrathchild/D5's? I assume it's overkill as you alluded to. I think a Wrathchild front would be key in fresh snow, but the majority of the time, there will be tracks ahead of me (we've got a time slot to get the segment in), so plowing through fresh snow probably isn't all that likely. In that case, I might lean towards a D5/D5 combo. And then what about studs .. I'd be tempted to not put studs on the D5's, but they inspire so much confidence I think they're worth the weight penalty.

And agreed on switching tires being a PITA. My older set of D4's would not seat/hold air after awhile. I think they became blown out over time. I ended up having to run 10+ PSI just to keep from walking home on a segment run. Two sets of wheels are likely in my future.

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More aggressive tread than a D5 doesn't really do anything for you IME. By yourself exploring, yeah, it can be nice, but in a race, rolling resistance over miles really adds up. That's why I keep going back to something like a D5. There's also a much finer line between what is ridable and what is not IME and the tire simply doesn't make as much difference. It makes a little difference, but not as much as we'd like. If conditions are soft and people are pushing, it's far more likely that everyone is pushing vs. one person is able to ride because they have wider more aggressive tires. Sure, it happens, but it just doesn't happen enough to be faster and lines get all rutted out and deep in those conditions so even if you have the more aggressive tires, the track is crap by the time you get there, so it just doesn't pay off IME. A little wider does help for those days and conditions, but rolling resistance is still king.

Studs on the other hand, they don't appreciably slow you down or have any negative, only positive. They add a very tiny amount of weight, like 20g, but it's almost negligible. You can even partially-stud a tire, going every other hole or a certain pattern like center rear, outside front. With our conditions, it makes sense just to run studs all the time, doesn't slow you down. A few fast racers will run fast-rolling non-studded tires in races in certain conditions. They make a lot of noise on pavement, but they aren't slowing you down on the snow. I notice a similar effect when I'm riding my fat-bike in gravel races where my rolling resistance compared to the full on gravel bikes isn't bad on gravel, but on pavement it is pretty bad. When we reach the end of a pavement section or the beginning of one, the difference between the two bikes is dramatic for rolling resistance...but on the gravel, much closer than you'd think.

Hoping to add to the discussion and not hijack it. Most of them seem to run d5's. I'm curious how a 26" D5 would race compared to a 27.5 D4. I get rollover is better, but that isn't as big a deal riding snow trails. It seems like there would be more weight to spin up on the 27.5.

I currently have 2, 26' wheelsets. Carbon set I leave wrathchild on permanently and it's the one I ride most in the winter in Minnesota because they seem to work for hardpack to pretty loose and I like having studs for piece of mind. I ride a mile to my local trail and the plowed asphalt paths can have ice lurking. My 2nd wheelset is aluminum mulefut that I use with 4.0 Jumbo Jim's in summer and Bud and lou for deep, loose, unpacked snow in winter.

I'm never going to win races here but I'd like to be a little more competitive. I think I lose more time in the winter to the top guys than I do in the summer. I'm guessing some is bike handling and some might be rolling resistance. I'm about 5'9" and 145lbs in the birthday suit so I'm not a big guy.