I just finished the leadville stage race this summer (10:47 finishing time) and was not weight conscious during the race (I road bigger tires on a 130/130 full suspension bike, I carried all the water I needed for the day in hydration backpack along with lots of food, sunscreen, mechanical bike stuff, I was 205 lbs race day, etc…)

I am curious about your thoughts on the rough effect of weight on finishing times in leadville 100 MTB (I am signed up for this next year)

How much finishing time do you think each pound saved is worth? For example, if someone had a 5 pound lighter bike, carried 4 pounds less gear, and lost 16 pounds, total fewer pounds would be 25 lbs (probably realistic weight differential in my scenario). What would you estimate that 25 pounds roughly worth in terms of finishing time at leadville 100?

Tough question. You can use bestbikesplit to do some calculations. I would imagine if you can get rid of that much weight, it would help a decent amount. When I did LV last year and was going through my equipment choices I was definitely thinking about weight but didn’t go crazy. For example, I though about switching out my dropper post to save about a pound. Glad I didn’t…that would have been <0.5% of the total weight (bike, rider and gear) and I found it really helpful. I tried to ask myself the question “do I need this to get to my special needs bag if I have a problem?” So I carried a somewhat larger tool kit than a typical ride (missing link, tubeless repair tool, etc. although I always carry that stuff now). But…I only took one spare tube. Ask yourself similar questions with nutrition.

Thanks for feedback. I am a statistician by training and can’t help but think of things like ‘the average relationship’, even with some wide confidence intervals

For a 25 pound weight difference (with everything else the same- power, etc), do you think the time difference over the leadville 100 full course would be closer to:

• 10 min (less than 30 seconds per pound)
• 25 minutes (one minute per pound)
• 50 minutes (two minutes per pound)

I was thinking the answer is somewhere between 10-50 minutes, but not sure how unrealistic those tail ends are

My gut would be 25min but that’s just a wild guess.

Assume you spent 60% of your time climbing, that would be about 6:30. (If you have something like the Elevate add on for Strava you can check this.) The total weight of the rider + bike + gear was about 250. If you drop that to 225, all else equal you will climb it in 225/250 = 90% of the time or around 5:48 saving you a little over 40 minutes.

Very interesting, thank you. A bit higher than I would have guessed

I just played around with bestbikesplit.com. It did a good job of predicting my finish time from all of my profile information. Dropping my overall weight by 5 lbs resulted in about 10 mins of time savings.

also - i went back and calculated i Spent ~61% of my time climbing for the leadville stage race this summer, so your estimate of 60% was spot on

I tried to figure out the answer to this question a couple years ago for both weight and watts. I used the bikecalc app and played around with grade, time climbing, etc. I’m not sure how accurate I ended up, but I convinced myself that both a pound and a watt were each worth about 90 seconds on the leadville course. Far from perfect science, but close enough to make some decisions. That’s using a baseline of around 165lbs and 190 watts. You really need to have a baseline for both power and weight to answer this question because the time difference per pound varies depending on the watts you are putting out. For a rider averaging 200 watts, losing/gaining a pound is going have more impact on time compared to a rider averaging 300 watts.

For what it’s worth, 190 watts (NP) at 167 lbs can get you in under 9 hours if things go well (no mechanicals, short stops, good groups to draft off).

Agree with you grwoolf. You were around 2.5watts/kg (NP) which is roughly what I was at during the stage race, where I finished with a total time of 8:38. For the 100 I was more like 2.33watts/kg (NP) which put me in at 9:18.

I was 2.36w/kg (NP) this year and finished 9:23, so that’s pretty much dead on with what you saw. I had a mechanical that cost me 5-7 minutes early and then the wheels kind of came off with nutrition and general execution.

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I don’t like such simplistic back-of-the-envelope calculations. Take your bike: with 130 mm travel, I am sure it is a lot heavier than my sub-10 kg XC hardtail. But having a more upright seating position, rear suspension and a larger safety margin all contribute to a comfortable ride, which is super important on these long races.

Ditto for your backpack: I cannot drink from bottles when I navigate technical terrain, which is why I love hydration packs on longer mountain bike rides. I also sweat a lot, which means I need to drink a lot. (Some of the really fast riders seem to be camels, hardly needing any water.)

I’m not saying saving unnecessary weight and optimizing your gear next time won’t pay off. But simply to not get lost in weight.

Here is another suggestion: take the money you have saved up for that new, lighter bike and invest it in bike handling. Get a skills coach or do a skills clinic. Then practice. Just like with training your legs, if you push your limit up, you also raise what 50–80 % risk level feels like. Then lose weight. I don’t know how tall you are and what your body fat percentage is, but at 93 kg, I am sure you could lose a few kilos.

Thank you for the thoughtful reply!

Some context for me (and in case its helpful to anyone else)

I don’t like such simplistic back-of-the-envelope calculations.

Quantitative science is my profession and one of my passions. I really enjoy this sort of intellectual exercise…there is certainly no single right answer (as is true in my work). But…we can often put some boundaries around what a reasonable answer is, which was my goal in thinking about and understanding based on those with more experience than I have

Ditto for your backpack: I cannot drink from bottles when I navigate technical terrain, which is why I love hydration packs on longer mountain bike rides. I also sweat a lot, which means I need to drink a lot. (Some of the really fast riders seem to be camels, hardly needing any water.)

I agree - I bought a good hydration backpack (but heavy, which is great for my long non-race MTB rides) and carry a single bottle with calories in it (And gels for longer rides). Its nice to have the space in the pack for everything. I have always been sweatier than most in the sports I play and I find I need more water than most of the people I cycle with. Not sure why, if its biology or training (I am relatively new to endurance sports, started in my late 30s )

Here is another suggestion: take the money you have saved up for that new, lighter bike and invest it in bike handling. Get a skills coach or do a skills clinic. Then practice. Just like with training your legs, if you push your limit up, you also raise what 50–80 % risk level feels like

Completely agree! I took two skills clinics in the past 9 months and it really opened my eyes to my lack of MTB fundamentals. I had a lot of hours in the saddle on a MTB prior to that and thought I knew what I was doing, but I was wrong - I learned so much in just the two clinics and it really changed my riding this year. I did it in Boulder through Boulder MTB alliance - highly recommended. They are a non-profit with reasonably priced group clinics with progression all summer, and year round private coaching. I took a private lesson for two hours and it was unreasonably cheap (100 bucks or less I think), and it was really quality. Looking forward to doing more of that. I ride MTB about once a week on blue/black trails in the front range of CO. For the leadville stage race I just completed I did not find my MTB skills to be holding me back , but certainly my excess body weight and relatively low FTP made it harder. It was my first race or organized ride of any kind, and the longest effort I have ever completed.

Then lose weight. I don’t know how tall you are and what your body fat percentage is, but at 93 kg, I am sure you could lose a few kilos.

Agreed again…not sure what my body fat percentage is, but my stomach sticks out several inches past my chest. I am ~ 6’2" and 201 on the scale this morning. I lost ~16 pounds in the past 3 months prepping for the stage race, and hoping to lose another 20-25 in this next 12 months (or as low as I can reasonably get, maybe lower).

Re: money / buying a new bike…money is relative to be honest. I wouldn’t say I am saving up for a bike and doing more skills clinic means I couldn’t buy a new bike. I work a fair bit and have limited hobby time, so these days I am able/willing/interest to drop \$\$ on my hobbies for the smiles. Over the next 8-9 months…If I can get down 20-25 pounds, raise my FTP from current 280 up to 310-320, and thought I had a good shot at going sub-9 hours, I would happily spend the money on lightweight equipment for that extra advantage. If I fail to lose the weight/gain the power, I have no interest in spending the money on the bike

But I think this stuff is so personal…if you have the \$\$ and it brings you smiles, why not…life is unpredictably short some times…earlier in my life there is no way I would spend the \$\$, it would have been irresponsible given my poor finances and cause too much stress. Now the thing I lack is time rather than \$\$, so when doing something like this, time is the scarce resource rather than \$\$

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2.85 w/kg for 8:13 in 2022. 2.7w/kg for 8:44 in 2021 (bad execution). I’m thinking that at 3 w/kg and I’m sniffing sub 8. So… I could lose 5 pounds and gain 10 watts. Or lose 9 pounds and keep power the same. In my opinion, this race is highly correlated to w/kg.

On Payson McElveen’s most recent podcast, he said that 1 lbs of extra weight costs an extra ~2-3w. So carrying 10 extra lbs costs you. 20-30 extra watts on a climb.

Improving your skills and optimising your set up are not mutually exclusive.

Other benefits of a “race” XC bike are an increased efficiency in terms of pedaling platform. I don’t subscribe to the Hardtail idea, but for sure there are easy gains in terms of efficiency that will also come with a lighter bike. Something like a Blur TR or other bike will be fast for anything you throw at it and still super capable.

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I heard him say that too, but it seemed real “out of thin air”. I honestly don’t know, but wouldn’t it scale for steepness/speed?

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Fellow scientist here!

Sounds like you already thought of all of that.
Glad to hear you liked the skills clinics, practicing skills is really worth it. If you get better at e. g. cornering, then a corner or feature that previously was a 7/10 is now a 4/10 or 5/10. So you can either go faster or be more relaxed and have more headroom.

That sounds like a very healthy attitude.

AFAIK if money is no object, then in most situations, most people are better off on a fully. You have more traction and more comfort. On long races like Leadville, the added comfort alone could be worth it.

But a good hardtail with a comfortable carbon seatpost is extremely capable and comfortable, too. And it rewards good line choice.

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Yeah, that’s why I was arguing for a 120mm XC bike.

Completely agree, the only place I’d consider a HT is for something like Leadville. I’d never recommend it for someone as their only bike though personally unless they never ride anything technical.

Unless they prefer them …
I switched back from a fully to a hardtail, and boy, did I miss the feeling. In an ideal world, I’d have a big garage and both, but my wife imposed a strict 2 bike limit — so a road bike and a hardtail it is at the moment.

Logically speaking, you are totally right, though.

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