jonathanf2

Just for fun, I've been trying to improve my time on a short downhill Strava segment. The KOM is 55 seconds with over 14k efforts from various cyclists. My PR without really trying is 1:12 minutes and that was going aero tuck while having a few cars in my way. I tried again the other day, but this time I went with a pedal sprint, but my time was actually slower by 1 second at 1:13 minutes. There wasn't any traffic either so I was able to go all-out. I was actually surprised I was slower. My goal is to at least shave a few seconds on my time and eventually get under the 1 minute mark. My top speed was just under 40mph, with the KOM topping out at 44mph.

My question: would I be better off getting as aero as possible once I pedal to speed, but the end of the segment it flattens out so I presume I should sprint that final leg? Also my current big crank is 50t, would I need a larger big chainring to even get any faster? Would mounting a heavier wheelset help create more downhill speed? Again it's just for fun, but I like the idea of trying to improve for this particular challenge. Thanks for any suggestions!

Elvo

Get a running start and get as aero as possible which probably means slamming the stem and sitting on the top tube. Also 50x11 is too low, you would need something like 55x11 at 120 rpm to beat 44 mph

jonathanf2

Darn, not really looking to buy a new crankset, though I do have a BSA compatible crank on my single speed bike. I could temporarily swap my current crank and get a cheap 56t chainring off Amazon just for this segment and run it 1x. Only problem it's a PITA to get to that segment since I need to hill climb to get there. I have a 1cm spacer between my stem and top tube, would slamming it even further make much difference? Also I'm on a slightly smaller frame and my stem runs at 130mm, so it's pretty easy for me to go super aero tuck and ride the top tube. Also you think weight cutting would help get more speed for the descent? I'd have no problem carb cutting for a week and reduce 10 pounds off my body just for this challenge. My riding buddies think I'm a bit crazy obsessing over this short road segment, but I like the idea of trying to overcome a miniature challenge that no one will even know about!

genejockey 

The best thing you can do to increase your speed on a downhill is to gain a lot of weight. Start with a big breakfast with bacon, eggs, hash browns, and a stack of pancakes with butter and syrup. Drop off at the donut shop on the way to work and pick up a couple apple fritters. Find a sandwich joint that makes really big sandwiches for lunch, and remember to get some chips and a big brownie. And a 32 oz. soda. Have a couple candy bars at break time. Pizza for dinner, and a big slice of pie for dessert. More pizza as a midnight snack.

You'll have a hell of a time getting to the TOP of the descent, but you'll be unbeatable going down it.

Seriously, though - if the descent is long enough, spin out your biggest gear, seated and in the drops, and then tuck for all you're worth. Flatten your back enough that you start worrying about your jersey pockets acting like tiny parachutes. I also point my knees in toward the top tube. Never done supertuck, though. Generally I keep my hands in the drops on the brakes, since 40+mph can be scary when you're only wearing a few oz of lycra.

HTupolev

No. Weight loss is usually a net penalty on steep descents by reducing gravity assist, and short-term weight loss efforts typically cause significant loss of strength as well.

I suspect you would have a hard time losing 10 pounds in one week through carb cutting, actually. Even a week of total starvation would be unlikely to give that result.

SoSmellyAir

Or draft behind a lead vehicle travelling at 45 mph driven by someone with whom you have previously coordinated the move?

Elvo

What segment is it? Cutting weight would reduce your frontal profile and increase your power to weight ratio so you can get a better running start. Also good to make sure you have your affairs in order like designated beneficiaries, will/trust, and advanced medical directives.

genejockey 

Other serious advice - hubs. One of my bikes has 7400 series Dura Ace hubs and it is about an mph or 2 faster than any of my other bikes. Also, if you're trying to beat a record, find a day with a tailwind. That bike, on a day with a strong tailwind, I broke 45 mph on one descent that's part of my Sunday rides, where I usually max out at 42.

WhyFi

Forget cutting carbs - cut liquids! That'll get that 10 pounds off pretty quickly.

mcours2006

Skinsuit, aero helmet. aero bike, aero wheels, Superman tuck...that should get you those precious few seconds.

Koyote

And don't forget to fill up both water bottles, and maybe tuck a third full bottle in your jersey pocket - gravity is your friend on descents.

tomato coupe

The first thing you should do is commission a gravity survey of the route. There may be some gravity gradients you can take advantage of.

urbanknight

According to Sheldon Brown's gear calculator, a 52x11 at 120rpm is about 45mph, and a rider with good form could pedal much faster than that.

jonathanf2

I have no problem with controlling my weight. I've done keto, and cut 30 lbs. in a month, plus I strength train regularly. A week is nothing for 10 lbs.!

Iride01 

Really? Downhill segments are a thing? Geesh!

urbanknight

I gained 60lb during my hiatus from the bike, and now descents where I would mash the pedals to stay at 40mph, I am coasting at 44+. Still don't recommend the weight gain though.

jonathanf2

Well I'm guess whomever KOM'ed the segment was in normal cycling gear, so I'm not sure it's worth going full aero!

WhyFi

I agree, if you're talking primarily about water weight. 10lbs of fat in a week? That would definitely not be nothing and would be damn near impossible.

jonathanf2

I know it's ridiculous, but it's a mini segment on the tail end of a climb and descent which I do every week. It's just for fun!

WhyFi

Take a look at the leaderboard and see if the KOM holder and a number of people in the top 10-20 all happened on the same day. In any area with a decent number of strong riders, groups are almost always a big factor.

jonathanf2

The first time around when I did the descent, I did have slightly more water and gear on me. I might pack as much water on me the next attempt and see if that'll help

Iride01 

45 mph isn't unreasonable to me though I'm in rare form (for me) when I get that fast on the short downhills here. We have a lot of people that show up as the KOM for various segments around here, but when you look at their entire ride, it becomes obvious that they finished their ride somewhere. Put their bike in the rack and forgot to turn off their bike computer while they drove like a bat out of hell for the trip to the house.

Although I'm not entirely sure that's part of your questions. I just got that idea from some of the replies I read that might have let my imagination take hold of reality. <grin>

I didn't even read all of your replies, much less the entire thread.

jonathanf2

That just gave me an idea, if I get my buddies to help me draft, I could potentially gain more speed. From the looks of it, the leaderboard happened during different times and years.

genejockey 

I was able to hit 44 mph on a descent where I usually max out at 38 by drafting a pickup with a camper top. In retrospect, and with the benefit of 20 years more experience and wisdom, drafting a stranger at that speed was probably a bad idea.

Bob Ross

^^^This. Anyone intent on chasing Strava downhill segments should Google Kim Flint.