Build a bike for short climbs? Select what?

[stormer94]

I've got some short hill climb opportunitys this summer. Was thinking aobut the possibilities of building a bike for these specific events. Most are 1 mile up a 5-10% grade. Nothing outrageous.

I'm tossing around the idea of building a specific bike for this. No good reason, other than it would be fun.

I'm gonna scrounge this thing together and have no particular loyalties to any company, although I seem to have a pile of Trek bikes.

FIRST THOUGHT. It seems to me that the lightest possible rim tire would be a good start. But what about looking at 650 stuff instead of 700. given the same weight the 650's would have to take less energy to spin up to speed, and the speeds are low, likely 12-15mph MAX.

SECOND THOUGHT. Absolutely strip the bike. No front brakes, no front derailer, no front big sprocket. cut the drops off the bars, and maybe even put a mountain bike bar on it... etc..

I think it would be fun. Any ideas? (I've got some good wheels now, zip 909s, Rolf Prima, etc..) and I'm willing to put maybe $2g into the bike.

Thanks for brain storming with me.

 

[JohnO]

Couple of thoughts:

You can't climb hills without also coming back down, sooner or later. Brakes don't weigh very much, and you may need them on the other side.

Buy the 2004 TDF DVD set and look at the equipment used on the mountain stages. (a real mountain bike - they actually climb mountains) Light 700c wheels, lighter forks in some instances, but otherwise a fully equipped bike. I did notice that a lot of riders pass on the indexed shifter for the front, and go with the old style downtube shifter. Probably for reliability reasons.

My hill climbing ability has soared in the past year, but it wasn't because I lightened the bike. I started climbing a lot more hills. In the end, cycling performance seems to benefit more from engine work than anything.

 

[stormer94]

Couple of thoughts:

You can't climb hills without also coming back down, sooner or later. Brakes don't weigh very much, and you may need them on the other side.

Buy the 2004 TDF DVD set and look at the equipment used on the mountain stages. (a real mountain bike - they actually climb mountains) Light 700c wheels, lighter forks in some instances, but otherwise a fully equipped bike. I did notice that a lot of riders pass on the indexed shifter for the front, and go with the old style downtube shifter. Probably for reliability reasons.

My hill climbing ability has soared in the past year, but it wasn't because I lightened the bike. I started climbing a lot more hills. In the end, cycling performance seems to benefit more from engine work than anything.

I just think it would be fun. Gotta take your motivation where you can find it. I'm guessing you can come down a 10% grade with just the rear brake and be fine. Mind you, it's only a mile run, and it leads to a flat area.

The goal wouldn't be to critique my fantasy, but join in and have some fun. I'll build it, and test it to see if it was worth it. It'll be fun.

 

[mises]

Unless it's a closed course I wouldn't descend a molehill with no front brake.

Assuming you have all the lightest parts to start with everywhere else:
- ditch the front der
- ditch the big ring
- use down tube shifter if possible, otherwise gut the brifter for the front der and ditch the rubber hoods
- shorten the chain
- no bottle cages
- alloy cassette, or if it's a fairly constant grade individual ti cogs but only use a couple and the rest just spacers
- assuming you are keeping the brakes use corima pads
- use the oldest most threadbare clothes you have and don't forget to completely relieve yourself before starting. ;-)

 

[dhk]

Good suggestions. I'd ditch the rear brake though, and keep the front. Guys with track bikes on the road here do this all the time and it seems to work.

 

[allezkmiec]

Good suggestions. I'd ditch the rear brake though, and keep the front. Guys with track bikes on the road here do this all the time and it seems to work.

Agreed. The front brake has more stopping power to begin with, plus you have the advantage of being able to run much less cable and housing. Speaking of which, use Nokon alloy housing and Powercordz brake cables, you'll save 2-3 ounces.

Aside from that, get rid of the following:
-rear brake, cable + housing
-front derailleur
-big ring
-your 4 biggest cogs
-the padding on your saddle (strip down an old one)
-the drops of your drop bars
-STI shifters; downtube are way lighter
-bar tape (who needs it for 1 mile?)
-any extra seatpost length (leave 3 inches inside frame)
-bottle cage bolts (cover the holes with electrical tape)

Run the absolute lightest tubes and tires you can find, as durability and flatting aren't a real issue. Performance Lunarlight tubes and Veloflex Record tires combine to weigh 185 grams; this is 30 grams or so lighter than Michelin ProRace tires alone! Use Rox rim tape instead of Velox, save an ounce. Hope all this helps!

 

[supergrill]

...
FIRST THOUGHT. It seems to me that the lightest possible rim tire would be a good start. But what about looking at 650 stuff instead of 700. given the same weight the 650's would have to take less energy to spin up to speed, and the speeds are low, likely 12-15mph MAX.
...

Nope. As tempting as it would be to think so at first glance...Less energy to spin up to same rpm, but the smaller diameter dictates that you have to spin them up to higher rpm to achieve the same speed.

 

[wilmar13]

Agreed. The front brake has more stopping power to begin with, plus you have the advantage of being able to run much less cable and housing. Speaking of which, use Nokon alloy housing and Powercordz brake cables, you'll save 2-3 ounces.

Aside from that, get rid of the following:
-rear brake, cable + housing
-front derailleur
-big ring
-your 4 biggest cogs
-the padding on your saddle (strip down an old one)
-the drops of your drop bars
-STI shifters; downtube are way lighter
-bar tape (who needs it for 1 mile?)
-any extra seatpost length (leave 3 inches inside frame)
-bottle cage bolts (cover the holes with electrical tape)

Run the absolute lightest tubes and tires you can find, as durability and flatting aren't a real issue. Performance Lunarlight tubes and Veloflex Record tires combine to weigh 185 grams; this is 30 grams or so lighter than Michelin ProRace tires alone! Use Rox rim tape instead of Velox, save an ounce. Hope all this helps!

If you want to get really crazy, it is only a mile after all:
-lose the seat and the post altogether
- convert to single speed, this will allow you to remove all the shifters and derailuers, keep the front brake and brake lever only.

Should be easy to end up with a sub 12lb bike with really light wheels.

Wait a minute, why not just convert it into a unicycle, I mean all you really need is a crank and a wheel...

 

[dhk]

Nope. As tempting as it would be to think so at first glance...Less energy to spin up to same rpm, but the smaller diameter dictates that you have to spin them up to higher rpm to achieve the same speed.

Sounds good on the surface, but the inertia of the wheel is based on radius squared (times mass of the rim), while the rpm needed for a given ground speed is only a function of the radius. So, advantage in acceleration goes to the smaller wheel at a given weight.

Still, this is small stuff. I'd not worry about acceleration though for this hill climb, and just pick the very lightest weight wheels and tires, whether 650 or 700.

 

[mises]

Old flite saddles work great stripped down. I think they are more comfortable without padding and with the shell drilled anyway.

650 wheels have higher rolling resistance and there would be no aero benefit on a steep climb.

Forget clinchers and go tubular. You can get under 1000g for a wheelset if you have the budget.

 

[mark higgins]

In the UK we have a hill-climb season in Sept-Oct. Lightest bikes are Fixed wheel, front brake only. Wheels definitely tubs.Zipp or Corima track wheels, 700c.Tubs Veloflex Record or Vittoria track tubs. Cut off bars. One lever for low-profiles on the end(Syntace,Vision Tech,etc). Nokon cables. Sella Italia C64 saddle.Tune seatpost.ITM magnesium stem.Frame as small as possible-?44cm. Tubing DedaV107. Front brake Zero Gravity. Should be pretty light 10-12lb.

 

[grampy bone]

You could go "old school" and start drilling holes in everything (except the tires).