The Analyzer Presents: Top Fuel Diet Series

Over the next few weeks I’m going to post about a variety of upgrades and tweaks to my Trek Top Fuel 9.8SL that all center around one thing: dropping weight.  You often hear about lightweight bikes and parts, but why?

With all other factors equal, a lighter bike will accelerate and climb faster than a heavier bike.  Those of us who slept through Physics 1 can at least conceptualize that, and if you’ve ever jumped on an ultra light bike you probably noticed how it just jumped even around a parking lot.  For those who made it through a bit more Physics and calculus, here are some formulas for you to use courtesy of the Climbing Cyclist.  The synopsis is that climbing speed is dependent on power to weight ratio.  All that riding you’re doing is working to improve your power, so you can improve the other side of that ratio by reducing weight (both on your body and on your bike).  That’s why goofballs like Phil Gaimon remove their front brake or hack off half their handlebars for hill climb KOM efforts (ok, maybe that’s just him).

How much of a difference does weight make? Down here in flat South Florida, not as much as places with real elevation and steep grades. In this introduction to gradients and cycling they ran numbers for a 5% grade hill for about 4 miles, and dropping 5 kg off the combined bike & rider saved about 30 seconds.  For your local group ride that might not be earth-shattering, but for me it is. This flat-lander is looking at ORAMM, with 10,000 feet of climbing, and wondering how the heck I’m going to survive. One of the climbs from Curtis Creek Road up to Blue Ridge Parkway is over 6% grade for over 10 miles, with sections much steeper than that in there.  

The fast guys are doing this climb in around an hour, I’ll probably be closer to 2 hours.  That’s just one of the climbs, then you’ve got Kitsuma. Twice. So yeah, if I can save a minute here and a minute there by replacing a few parts on the bike, it might be a good idea.

Now, the 2017 Trek Top Fuel 9.8 SL is a really light bike out of the box.  Carbon frame, wheels, bars, seatpost, crank-set etc. all from the factory.  I’ll post the starting weight next week but as I recall it’s under 25 pounds as I raced it in the Florida Endurance Series.  Over the series I made a few notes about tweaks I’d like to make once the race season was over and I’ve gathered a few parts to that end. One mantra I’ve always held when working on cars/bikes/etc is “Don’t replace, upgrade”, which is good for the scale but bad for the wallet.  To that end, I’ll be posting the prices so we can look at dollars per gram saved, to see which upgrades make more sense than others.  

When you start chasing grams on the bike, it’s easy to get caught up in ultra light parts that may have compromises.  Hopefully in this process I won’t compromise any reliability or rideability while saving grams.  That means no carbon fiber brake rotors or drilled rims or any other crazy stuff.  Just simple, reliable and reasonable weight weenie upgrades.  

So if cutting weight off the bike is good, why don’t I just take my Trek Superfly Single Speed since it’s around 18 pounds?  Because I may be crazy, but 61 miles up and down the highest peak east of the Mississippi with 1 gear and no suspension is another level of crazy I have yet to achieve.  The thought has crossed my mind though….

Of course any discussion about dropping 50 g from a bike ultimately ends up in, “yeah, but you could just not eat burritos all the time and save even more weight off your body”.  Yes, this is true (and I’m doing that too), but the main problem with that is burritos are delicious.  The guys at Global Cycling Network looked at that a couple years ago and it’s worth a watch:

So over the next few weeks I’ll be going through the bike and seeing where I can cut a little weight, posting the outcome at each step including weights of each component I’m replacing.  If you guys & gals have any suggestions or tips just let me know and I’ll try to work it into the series.

 

Leave a Reply