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Discussion Starter · #1 ·
Interesting experience yesterday riding with a good buddy on his carbon Spesh 6fattie. We traded bikes midway up just to compare and let him check out my Ripmo. We both immediately commented that his bike felt faster uphill / less fatiguing in the same gear. I'm wondering if there are factors that could affect that other than the normal (tires, wheel weight, cassette weight, etc) because by most of the variables we could come up with his should be slower. For reference:

Tires: him Purgatory Grid 27.5x3.0 front and rear - 1100gr each. Me DHF 2.5f, Aggressor 2.3r - 1050 and 900gr I believe (advantage me I would think)
Drivetrain: him GX Eagle with 32/34 oval, me GX cassette and crank with NX shifter and derailleur, 32t GX chainring (should be a wash)
Him 175 crank, me 170 crank both GX eagle (mine lighter, his more leverage?)
Pulled the chain off and both cranks seem to spin with about the same freedom - mine may have had a TINY bit more resistance.
Wheels: both DT swiss XM rims (his are 40mm internal, mine are 30f, 25r) similar hubs (Hope for him, DT350 for me) so I think wheels are close to a wash or an advantage for me.

Anyway, we both found it odd that his heavy / beefy tire setup with similar drivetrain felt easier to pedal uphill, especially given the efficiency of my suspension.

Could it be shifting adjustment affecting resistance in the upper gears? I don't hear any grinding. Maybe it just is what it is, but figured I'd see if there was anything else to check to see if mine could be improved.
 

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Fork and damper setup is crucial.

Wrong sag and everything feels wrong. Too much sag at the back and the whole bike feels soggy and unresponsive while climbing. This is especially true for DW-links in my experience. 25% sag?
 

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Brakes not rubbing I assume? You mentioned he's running 175s with an oval and you're running 170s with a round chainring...that alone can definitely have an effect on steep climbs IMO, especially depending on the mechanics of your pedal stroke.
 

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When you say easier, do you mean the gearing feels easier to pedal in the same cog, i.e. the 50t cog on both bikes? If so, then of course his would feel easier, his tyres are smaller than yours by a decent amount, about 1/2-3/4" diameter.

If you don't mean that, then geometry. No matter all the marketing BS in the world, you don't get anything for free, so that descending prowess you love, you pay for that on the climbs. That BS about steep STA making it a good climber, is exactly that. it's a good climber compared to other bikes with similar geo and travel, but compared to a bike with a steeper HTA and less stretched out WB etc, none.
 

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Discussion Starter · #5 ·
Fork and damper setup is crucial.

Wrong sag and everything feels wrong. Too much sag at the back and the whole bike feels soggy and unresponsive while climbing. This is especially true for DW-links in my experience. 25% sag?
I'll take a look but yeah sag in the DVO Topaz is about 25% - rear is plenty firm it seems. I'm on an MRP Ribbon coil fork and it's on the soft spring - I'm about 170lbs. Doesn't sag very much and seems to be about right for me.
 

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Discussion Starter · #6 ·
Brakes not rubbing I assume? You mentioned he's running 175s with an oval and you're running 170s with a round chainring...that alone can definitely have an effect on steep climbs IMO, especially depending on the mechanics of your pedal stroke.
Checking the brakes now, but I don't think there's any drag. I do know that the rear brake is not braking much at all right now. Full lever pull and I can't even lock up the tire. I think there's some contamination on the rotor - going to put a new one on, scuff the pads and try to re-bed them now. Good thing to check though!
 

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Discussion Starter · #7 ·
When you say easier, do you mean the gearing feels easier to pedal in the same cog, i.e. the 50t cog on both bikes? If so, then of course his would feel easier, his tyres are smaller than yours by a decent amount, about 1/2-3/4" diameter.

If you don't mean that, then geometry. No matter all the marketing BS in the world, you don't get anything for free, so that descending prowess you love, you pay for that on the climbs. That BS about steep STA making it a good climber, is exactly that. it's a good climber compared to other bikes with similar geo and travel, but compared to a bike with a steeper HTA and less stretched out WB etc, none.
Yes, gearing feels easier in the same cog. You think just the diameter makes that much of a difference? Wouldn't the heavier wheels and heavy tires also be a factor in that?

One interesting thing he and I were just talking about is that when he got his 6fattie, another guy who worked at the shop he was at got the Specialized Enduro. Same build, similar geometry, different wheel size and he said his was noticeably easier to pedal than that Enduro as well. Maybe there's just something about the 6 fattie geometry / suspension that works well.
 

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Strictly IMO, but when I ride with shorter cranks it often feels like things take a bit more effort (because... physics! ;) ). Not sure this is the case with you guys... but that's my experience.
 

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One other thing to take into account is tyre compound, if you're running the 3C MaxxTerra compound on your Maxxis tyres vs the regular compound on the Purgatories, the Maxxis compound rolls a lot slower. Also, don't fool yourself and think just because tyres are wider, that they roll slower.
 

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One other thing to take into account is tyre compound, if you're running the 3C MaxxTerra compound on your Maxxis tyres vs the regular compound on the Purgatories, the Maxxis compound rolls a lot slower. Also, don't fool yourself and think just because tyres are wider, that they roll slower.
Good points here. Tire compound and tread pattern can make a huge difference. The 2.5 DHF/Agressor is a slow combo and IMO overkill for most riders.

Even though the 29er tires of the OP are lighter they are farther from the axis of rotation so rotational intertia could actually be higher than the 27.5 bike with heavier tires.

If you want that Ripmo to roll faster lighten up the tires and go with something that rolls faster. I run a 2.4WT or 2.3 DHR up front (can't tell much of a difference, 2.3 is lighter), same cornering lugs as DHF but much shorter centers so it rolls faster. Out back I usually run a 2.35 Forekaster or Ikon depending on the trail conditions. Now I don't run this combo on a Ripmo but if I had one I probably would.
 

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Discussion Starter · #15 ·
I'd bet money it's the 170s, purgatory grid 3.0's are tanks.

Why you running grom cranks?
Grom cranks? I'm not sure what that means. I went 170 because I wanted fewer pedal strikes and had read some stuff saying they could be as, or more efficient than 175s. Although having had both now I do believe I probably like the 175 length a bit better.
 

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Discussion Starter · #17 ·
Good points here. Tire compound and tread pattern can make a huge difference. The 2.5 DHF/Agressor is a slow combo and IMO overkill for most riders.

Even though the 29er tires of the OP are lighter they are farther from the axis of rotation so rotational intertia could actually be higher than the 27.5 bike with heavier tires.

If you want that Ripmo to roll faster lighten up the tires and go with something that rolls faster. I run a 2.4WT or 2.3 DHR up front (can't tell much of a difference, 2.3 is lighter), same cornering lugs as DHF but much shorter centers so it rolls faster. Out back I usually run a 2.35 Forekaster or Ikon depending on the trail conditions. Now I don't run this combo on a Ripmo but if I had one I probably would.
There is no doubt tires could be part of it. I may try something lighter. I'm a pretty intermediate rider but getting faster, although I ride Colorado mountains and Phoenix area which is all rocks, so I at least want a strong sidewall. I may try some of the Specialized tires or go slightly less aggressive Maxxis next time and see if that lightens it up.
 

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Discussion Starter · #18 ·
With regard to the hub not being as free as it could be, when you lift up your rear tire and give it a good "The Price is Right giant wheel spin, about how long will your rear tire free wheel? I suppose I can compare it to my front wheel. I'll try that tomorrow. They are almost brand new DT350s
 

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With regard to the hub not being as free as it could be, when you lift up your rear tire and give it a good "The Price is Right giant wheel spin, about how long will your rear tire free wheel? I suppose I can compare it to my front wheel. I'll try that tomorrow. They are almost brand new DT350s
The problem is not your hub. A rear won't spin as long as the front wheel because of drag from the freehub.
 

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Discussion Starter · #20 ·
The problem is not your hub. A rear won't spin as long as the front wheel because of drag from the freehub.
Ah yeah, should have thought of that. But comparing to others' free hub spin might let me know if there's too much drag. It definitely doesn't seem to freewheel all that long and when it starts to slow down it slows pretty fast.
 
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