Newbie Assistance needed for 20km performance

[Bujon]

Hi All

Having been something of a demon runner in my younger days, and having given up to calf injuries 10 years ago, I decided it was time to get on a bike and see if I could anywhere near the same enjoyment out of that.

I purchased a £300 bike from ebay, a 2007 Schwinn Sport Back, which weighs in at about 10kg including pedals.

Ultimately I wan't to concentrate on duathlons, because i feel I still have the beating of most guys on the running sections even without any running training, but this leaves a great void of becoming mean on the bike. Why do all the multisport events weight so heavily on the bike????

By my calculations most triathlons/duathlons have the competitive cyclists averaging around 23-24mph, but I simply can't get near that!! I've been time trialling myself over 15-25k and the best I can hit is about 20.1 - 20.4mph. Where am I going to find 3mph? Aerobars?....It's also very strange that I find 18-19mph very easy and could cycle for hours, but yet 22mph I can only hold for say only 3-4 miles?....I seem to be inbetween gears if that makes sense, also does the length of the pedal stems have a big influence?

Any tips?

 

[kdelong]

The theory behind crank arm length is is tied to the riders leg length. Longer arms aid uphill riding because the longer arms give a rider more leverage. However, they are more difficult to spin so they limit leg speed. This does not present a problem for riders with long legs as their longer thigh muscles benefit from the longer arm length. A longer arm length hampers the riding form for riders with short legs, so while they might help in climbing, they actually adversely effect the riding of shorter riders. If you have long legs, changing your crank arm length is not going to really benefit you. If you have short legs and you are using long crank arms, it may help to get shorter arms.

Actually, since you bought the bike off of eBay, has it been fully tuned up? Is the fit correct? I suggest that you take the bike to your local bike shop(LBS) and have them take a look at the bike and at the fit. It could be that you might benefit from a few tweaks here and there.

I also suggest that you pick up a book or two on bicycle training or maybe hire a coach for one or two training sessions to help you put together a training program. Once again, your LBS should be a good source for both if these. I don't know your LBS so if they cannot help you with this, find another bike shop that can.

Last of all, re-post this on the Cycling Training section of the forum and let some of those guys have a crack at it.

FWIW, you can get cassettes with different gearing that may provide you with the "in between" gear combo that you feel you are missing.

 

[daveryanwyoming]

Two thoughts:

- Train better as in regular 2x20 or 3x20 Threshold Sessions which are basically mini time trials backed off just enough that you can complete both (or all three) sustained 20 minute efforts.

- Get more aero and yes clip on aero bars (AND a good position) are worth a mile or more per hour in average speed relative to a good road bike position and perhaps more if you ride up on the tops or brake hoods a lot. Aero helmets are a good idea as well and if you've got the cash deep rimmed aero wheels help quite a bit but only if you first address your position and that means aero bars.

One big difference between running and cycling at higher speeds is the importance of aerodynamics. At race speeds where aerodynamics dominate in terms of the forces a cyclist has to overcome it takes roughly 8 times the power to double your speed. That's not true on steep hills at low speeds where it only takes a doubling of power to double your speed or running which is also roughly linear in terms of speed vs. intensity. But that cubic relationship between speed and power required to maintain it means a lot of folks feel fine up to a certain point as in your 18 mph pace but the jump to 22-24 mph seems enormous because it is.

Increasing your speed from 18 mph to 24 mph is only a 33% increase in speed but on a calm day on flat terrain that will require an increase in power of 137% unless you improve your aerodynamics. Or stated differently you'll have to put out nearly two and half times as much power to increase those extra 4 mph on the bike unless you get a lot more streamlined and that's where the aero bars and other aero kit comes in.

-Dave

 

[swampy1970]

The aero goodies are only a credit card away. Mmmm tempting. Aerobars and aero helmet are top of the list. Make sure too that whatever you're wearing is pretty tight and wont flap around in the breeze. Anything "baggy" will add significantly to your aero drag. If you're just doing a bike event then a skinsuit is one of the best bangs-for-the-buck you can get. Voler sells some good "fairly cheap" ones. It has to be tight though - which means that when trying it one it'll be a pain in the butt to get in and feel too tight when standing up. A rear disk wheel cover can be had for about $60 - not quite as good as aero as a full carbon disk wheel but it's a significant improvement over a standard 32 or 36 spoked wheel.

Other equipment bits too look at.

Tires - Get something that pretty much matches the rim width and when you're racing use latex tubes. Good racing tires from companies such as vittoria, continental or michelin are a worthy investment - as is a track pump to get to the correct tire pressures.

"gears" or more specifically the cassette. Chances are your 8 or 9 sprockets on the back wheel are more suited for general riding, which includes going up big hills. For a flatish time trial you'll want a cassette that offers a 1 tooth difference for most gears. Something like a 12-21 would probably work well. I'm guessing for 20mph you're using probably a 17 sprocket the most. With a widely spaced cassette (if you have 8 speed) you may well have a 15 and 19 either side of that. Going from a 17 to a 15 tooth sprocket is a bit of a jump. Going from a 17 to a 16 aint too bad. Honest

As Dave said, for the most part you want to do longer intervals of around 20 minutes for the most part but you'll probably do well to add in some shorter, faster intervals as well. 5 minute efforts will add a bit of top end and add variety.

When you do race, make sure you don't go crazy in the first minute or two. You'll want to set off briskly but you don't really want to be at race effort for a 30+minute TT within about two minutes of the start. Warm up really well and use that first couple of minutes to setting into your TT position and ramp up the effort. Depending on the courses, learning how to corner quickly may/may not be a worthwhile skill to learn at this point in time. Having to brake for corners just means that you're not at race pace and that you have to accelerate more to get back upto speed. A double pain in the glutes...