Bicycle Mechanics - The need for Speed - Long question, short answer - Please help

Very Long Question – very short answer.

To be able to fully understand my question I must tell you a little bit about my background, current situation and fitness level so you can help me with the technical part. If you don’t have the patience or the desire, just scroll down and answer the simple question.

I come from an athletic background that includes 3 years as a sponsored water polo player (age 18-21), 3 years as an adventure racer (age 23-26) doing 6, 8, 12 and 24 hours non-stop biking/running/kayaking and some decent running (5, 10, 15 miles keeping a sub 9 minutes/mile). I have a decent background in mountain biking (not the most technical man out there, but quite decent) and just love bicycles since I was 6.

Now I am 31, semi sedentary for the last 2 years (doing 2-3 miles on treadmill 1-2 times a week), spending a lot of time studying and communing between Tampa and Orlando twice a week. I am a graduate student and work part time, so the amount of time that I spend seated definitely increased for the last 12 months. I went from being 159lbs to 174lbs and my body fat went from 6% to 23% in 24 months. I am not in the best shape of my life

Since 2001 (last race), my nice mountain bike was hanging and, to adapt to my new lifestyle (graduate students shouldn’t be driving SUVs to commute twice a week approximately 80 miles each way) I got a sedan. I needed a bike that could fit in my car so I could stop having excuses to NOT ride. To make the (already) too long story a little shorter, ended up with a folding bike (for those interested, a Giant Halfway RS – rear suspension – with 7 speeds, 13-32 cassette)

Nice bike, needed a bigger chain ring (now featuring a nice 54T to compensate for the 20”wheels), faster/skinnier slicks and now I am semi-happy with my little thing, doing 70 minutes rides and being able to keep an average of 18miles/hr when I put a little effort (remember, I am in Florida, no down hills around here).

OK, now we can start talking about the technical part of it. I want the bike to go faster. I am getting tired from the spinning but not feeling the legs as I used to while racing. I just ordered the dual drive internal hub from SRAM (3 internal gears, 9 speed cassette, 11-34 Mega Range). But my real question is:

Who needs an upgrade, my bike or myself? In other words, the SRAM dual drive will give me 3 extra higher gears (one internal and the 12 and 11T from the cassette), but will add some weight and dragging to the bike. It will make it harder to pedal (which, by the way, is what I am missing) and even with the loss of efficiency and extra weight, be a little over geared if compared to what I have now. Should I just learn how to spin more efficiently or should I pursue my desire to hit the pedals harder? Will I benefit from the dual drive internal hub? After all, it’s a US$340.00 investment into a US$400.00 bike…

Thank you for any input about SRAM Dual drive technology, gearing and the technical aspect of just going faster.











For those with no patience, this is what I am asking:

To obtain faster average speed with my little bike, should I just learn how to spin more efficiently or should I pursue my desire to hit the pedals harder since I feel them soft and way too fast when I am speeding? Who needs an upgrade, my bike or myself?

Rafael
PS: Picture of current configuration of my little folding thing. Just the seat is not up-to-date on this picture (I got a nice Specialized road seat, no more wavy coils)

http://216.77.188.54/coDataImages/p/Groups/245/245228/folders/219703/1721347IMG0010.jpg

Sell the Halfway, get a road bike and some Yakima roof racks with locks.

Sure, you could spin more. What's your cadence now? But you're still throwing money at an inefficient bike that was never meant for speed. From a rigidity standpoint, as well as braking, you are simply using the wrong tool for the job.

if you are wedded to this bike, consider a schlumpf bottom bracket?

http://www.schlumpf.ch/

(they need to hire sheldon for web design)

@Expatriate: At this point in my life, for several reasons, getting a non-folding/road bike is not an option. :(
No solid idea about my cadence, but I can guesstimate 60-80 (when I am riding confortably) and above 100 when I feel like spinning more than I want. Any way to measure that without a ciclocomputer that measures it?

@Bikedude: Those are awesome, only read good things about them. Little pricey though (besides the fact that I had more feedback from rear hub users).

Thank you very much for your contribution.

Rafael

You could try to count your RPMs, or if you have a speedo on there, you can figure cadence for a given speed. But plenty of energy is being wasted with each pedal stroke.

Just count your cadence... free.

I'll count. Now, what is considered a good cadence? Any sites to learn more about it?

You could put a 58 or 60 tooth chainring up front. I know they exist, check around at recumbent and recumbent trike sites, that's where I've seen them. Not sure if they'll fit your crank's BCD. Turn the preload on your rear shock to the maximum, this should help a tiny bit with efficiency. Consider aerobars or perhaps a fairing.

You might try dropping the bars to get more aero. Or put on some drop bars. Or aerobars.

Get a cyclocomputer with cadence. One of the big mail-order houses has one under $30, closer to $20, I think.

Your biggest gear now is 80 inches. Track sprinters run about 89 to low 90's gears and for short spurts get up to what, over 40 mph?, so I'm willing to guess that you are not spinning that fast. An 11 tooth cog will get you about 95 inches. A 95 inch gear on my bike is a 52/15. That gear is the biggest I can use in a training race final sprint (not with the fastest guys, but still strong riders).

I guess my point is, you are not riding that small of a gear and are already crunching, not spinning.

What's better, spinning or crunching? Eddy Merccx was asked, "is it better to spin a small gear or crunch a big gear?" He thought for a second and said "its better to spin a big gear" A little cocky, but what he was saying is spin.

I guess my point is, you are not riding that small of a gear and are already crunching, not spinning.

But I'll still benefit from the 11T + internal hub that I ordered, right?

Thank you for all information. Sounds like now all I need is training and (maybe) some way to get more aerodynamic (may consider aerobars in the future).

Once again, thank you for all contributions.

Rafael

Regarding spinning: In my opinion, anyone interested in being really fast should aim to be able to smoothly spin about 120 rpm (2 revs per second).

For some people, this will require a different seat height (most likely higher) and/or a shorter crank length.

I have a folder which I think is about 5 years old, and has a 3-speed hub. (no external gears.) I like the bike, but I think that the inefficiency of the three speed hub is a significant part of the reason that that bike is so much slower than my road bike.

Cerewa,

Thank you for your info. I believe I can keep 120rpm, but not for too long (that helps me identifying the problem, which is a good beginning to fix it).

My understanding is that the internal speed hub technology really improved in the last 3 years. It used to be 90% of efficiency before and now it's almost 98%, still keeping an option that is direct transmission (100%). I may be wrong, but I don't think getting the speed hub will make things worse.

I guess all my questions are answered. I learned that I can benefit from higher gear, I learned that there is a lot of room for improvement on my fitness level (so I can keep a decent 120rpm for longer times) and that, no matter what, my folding bike will not be as efficient or as fast as an average road bike (which we all already knew, but is important to emphasize).

Thank you everyone.

Rafael

You need a cadence meter. Like Phantoj said, they're cheap, and can be transferred to another bike later if needed. By the time you count your cadence it has already changed.

Al

Your biggest gear now is 80 inches.

I get (54/13)*20"=83", which isn't all that big for cruising. At 90 rpm that's about 22 mph, and at 120 rpm it's about 29.5 mph. On flat ground that's pretty reasonable, but with a decent tailwind or slight downhill it will be easy to feel spun out in that gear unless you're used to spinning. 18 mph is about 74 rpm, which is respectable, but not all that high.

Mass start track racers tend to use gears in the 86" to 94" range, with most probably being in the 88" to 92" range. For an 88, 110-120 rpm will put you in the 29-31 mph range where a lot of racing happens, and in those gears you still have decent acceleration. It does take most people some practice to maintain those kind of rpms for very long.

The new hub (with an 11) will change the biggest gear to about a 98. Unless you're descending a lot of long hills (which you don't have in FL), that's not too bad. I used to ride 52/13 back in 7 speed days, and the biggest gear there is about 105" for a 700x23 tire.

Sheldon Brown has a nice gear calculator you can use online here:
http://sheldonbrown.com/gears/

You can use that to compare your setup with a typical road setup (these days it's 53/39 and 11 or 12 to 23 or 25). Keep in mind that 53-11 is an enormous gear for most people.

The short answer is that if you're not racing and not going for max speed while descending big hills, you'll probably feel fine once you have an 11 tooth cog. If you want to go faster on the flats then, and you're not in a paceline, I'd recommend learning to spin a smaller gear rather than putting on a slightly larger chainring, just to be nice to your knees.

Must add that the dual suspension is probably already robbing a lot of power, and I have this vision of 110-120 rpm on this thing... I would lock out the suspensions as well.

How are you going to put SRAM hub on a Halfway? Do they make a one sided one?

em

@BitingDuck: Thank you for your contribution. I really appreciate it.

@Zouf: Good point. This halfway has just a rear suspension, and I'll make sure it's not on "soft mode".

@Eddy: My Halfway is a RS (Rear Suspension) from Japan. It's a halfway with cantilever and monoblade fork but it's not a "real" Halfway since it has a regular rear hub. There is actually a tiny little bit of the distal side of the rear frame on the above picture.

Rafael