hch389

Planning on racing a 6.5% 15km uphill race this summer. Grade ranges from around 4-8%. (strava segment SEYSSINET - ST NIZIER SORTIE)

With a FTP around 4W/kg, I'm expecting a time around 55 minutes, 16kph (10mph).


I have a fixed gearing of 17/11 (unicycle hub) or 1:1. So, what I can change is my wheel size, or crank length.

700Cx32mm tires 17x11 = 42 gear inches = 80rpm (what I used to race Mt. Diablo in California at 5.6%, but also changed gears to 1:1 for the steep bits. Averaged 94rpm)

650Bx32mm tires 17x11 = 39 gear inches = 85rpm

36"x2.25" tires 1x1 .......= 36 gear inches = 90rpm

Is choosing between these going to make any big difference?


On the bike with 172.5mm cranks, I am a spinner and like 90-100rpm on hard effort.

On the unicycle, I'm usually prefer 150mm and similar cadences (shorter cranks reduces wobble).

So these 80-90rpm numbers are on the low end.


Is trying to raise my FTP by a few percent in 2 months what I should focus my time on, or buy+test different wheels that give me a lower gear ratio?

Herzlos

Do you live close enough to try the various combos?

For me, I'd be going for the easiest gearing and spin a bit, but many others would prefer the higher gearing and grinding.

hch389

I really wish I had big hills/mountains nearby. But the biggest hills around me (southeast Michigan) that I could find are less than 2 minutes long.

Using the one I have (biggest gear, 700c), I tried a 6.8% 0.45km (30m gain) climb, and could "easily" power over it regardless of cadence/power. (70rpm 200W up to 95rpm 300W)

Doing repeats didn't help much since it 2 minutes up is followed by 2 minutes down. 1 hr of repeats (15x), did make me feel that a lower gear would be more comfortable..

couldwheels

I found short repeats ineffective training for one long continuous climb. You won't learn how to pace yourself in short repeats.

If you need to train for 1 hr climb and you don't have 1 hr continuous climb nearby, your best bet is indoor training with the indoor bike tilted upward 6.5% to get used to the incline.

I know indoor training can be extremely mundane but may be your only hope of getting the right training in your situation.

PeteHski

As there are 8% sections and it's close to a 1 hour full gas effort, I would go for a pretty low gear. FWIW I'm also around 4W/kg and do a lot of alpine climbing (in the same gradient range) with a 1:1 ratio. It might feel a bit under geared for a 4% gradient on fresh legs, but if you can spin then it will pay dividends on the steeps and later in the climb. It will help with pacing too as you have more control over power/cadence with a lower gear.

sean.hwy

Damn you guys and your 4W/kg. At 4W/kg are you guys more or less in the top 10% of strava for like 5+ mile hill climbs?

Still trying to get in the 3s.... ha-ha

hch389

I am lucky I weigh <60kg. Not fun on flat terrain though haha. Top 10% in long climbs on strava for me.

So my current setup is effectively 622x32mm wheel with34t x 22t. (figure this translates better to how it might feel biking)

I'd love to try 584x32 wheel, to get a 6% lower ratio, equivalent 700c 34t x 23.5t

Next step is a 36" wheel with 1:1 ratio = 12% lower ratio, equivalent 700c 34t x 25t

29" wheel with slick 29x2.2" tire with 1:1 ratio, equivalently 700c 34t x 31.5t
Finally, straight up 1:1 gear, 700c 34t x 34t

Looking at it this way...I think the 34t x 25t sounds reasonable.. any higher gearing is a bit insane. 34t x 31.5 seems a tiny bit low if I'm racing...but maybe this is also a good choice give a 29" slick tire is likely faster than a hunky 36" tire.

Edit:
Also, the 2-speed geared hub can be changed while riding, so I could downshift to 1:1 from 7.5km to 9km when it averages 8%