airfoil71

I plan on competing in Time Trials in the spring and I have built my TT bike and have been contemplating using disks but not sure if it would be worth the investment. I know they may add an extra pound but not sure if the areo would make up for it. I said that about the areo helmet but purchased one anyway. It made a significant difference especially on windy day. What are your thoughts? Right now I am riding 23 miles an hour for 10 miles and 20 -21 miles an hour for 20 miles. Just giving you an idea of my level of training and level. I know this is a road bike forum (which I also do) but not having much luck with the triathalon folks. Any input would be appreciated.

Gramercy

What kind of bike do you have? What kind of discs are you looking at? How much do you want to spend? And is this course very flat? 23mph for 10 miles seems pretty fast as a solo ride, but I don't know that much. I think guys say you may gain .5mph or so on the time trial with more aero wheels. It's probably not as big of a difference as you're hoping for.

merlinextraligh

Assuming it's not an event run under UCI rules, a disc cover is the most cost effective answer. About $100. It will make a measurable difference in speed.

And unless it's a very hilly course, the speed advantage will trump the weight.

Dean V

It just depends on what you want to achieve. At your level you certainly won't be competing to win anything so the TT's will be more for personal achievement goals (which is what they are very good for). If you want to do that purely by fitness and position on the bike etc, that is fine. If you want to help it along a bit by buying some speed (wheels, helmets, frames etc etc), the decision is up to you. I would suggest you at least do a few TT's before throwing alot of money at it.

big chainring 

I'm going to give some advice that will seem totally off the wall but founded in historical principle. Do a TT on a fixed gear. The English were big TT riders and many rode fixed gear bikes. Do some training on fixed gear also. You can spend money on all kinds of gizmos but its all about putting out a sustained effort for a set distance. Learning to ride smooth and controlled with minimal bouncing and weaving is what its all about. Ride an 84-88" gear for a TT, and keep your RPM's up. Even go down to an 82" gear and get a good spin going so you can feel what a high cadence can do for you.
There is way to much emphasis on equipment these days. For a flat TT a good old fashion steel track bike is the way to go.

AngrySaki

If you haven't already gotten one, a power meter is probably a better investment than disc wheels.
I think the general consensus that I've seen is that wheels give less of a performance boost than an aero helmet.

If you want to waste time looking at data, you can look here: https://www.aeroweenie.com/data.html

airfoil71

I have Kestrel KM40 Airfoil with dura ace 9 speed drive train. Possibly some HED covers. Seen a set on Craigs List for 100 a piece. The lay of the land was kind of mixed. No real big hills. I have Rolf wheels on it already and happy with them but trying to gain some more speed. I have been a body builder for 10 years so I train hard and I want to be able to hold 25-26 miles an hour for 10 miles. I have eight months to gain two miles an hour, have strong legs and a lot of will.. LOL

airfoil71

Not a Pro by any means but there are plenty of time trials in which 25 -27 miles an hour do well and place when the course is not flat. You are right in one thing, I love to ride and I love to compete against myself and others. As a personal trainer, my motto is the body will only go where the mind will take it.. I will get better as a rider, just curious about the disks. I know an areo helmet increased my speed by almost two miles an hour and the geometry of the tt bike (kestrel air foil) also increased my speed over the trek y foil road bike that I ride.

big chainring 

You might find it interesting reading up on Arthur Metcalf and others that competed in the BBAR(British Best All Rounder).

Metcalfs achievements in the BBAR in 1966;

In 1966 he won the national amateur road race championship and, as an afterthought, the BBAR with a record average speed of 24.797 mph. The BBAR aggregated speeds of riders over 50 miles, 100 miles and 12 hours and specialist time-triallists usually devote their whole season to it. Metcalfe won in three straight rides, almost as an afterthought. "I remember thinking I needed a change. I'd ridden a few time trials in the past and so I thought I'd have another go," he said.[

valygrl

https://www.bikeforums.net/showthread...ead-click-here

OldTryGuy

112 miles in 4:02:17 by Andrew Starykowicz 2 Saturdays ago in IMFL. Truly a man who knows how to TT on a bike with gears. 1:58:47 for 56 miles yesterday at the Venice Rev3 70.3 triathlon.

Elvo

Just get a disc cover

merlinextraligh

Wut? Do you have an afro picked out to 4 feet wide?

Even the most optimistic data about aero helmets doesn't put the speed gain at anything approaching 2mph, particularly at 23mph.

The substantial majority of that speed increase was either placebo, or improving fitness.

Once you've got a good aero position on the bike, all the tweaks, like aero wheels, aero helmets, skin suits, not wearing gloves, water bottle placement, etc, are ways to shave seconds and pick up a fraction of a mph.

Meaningful at the margin when seconds count, but they don't get you multiple mph improvements.

wphamilton

I imagine that you couldn't put on an aero helmet and not ride any faster, you'd feel like a fool so I'm not totally skeptical. I'll bet a skinsuit would work the same way. Disk or covered wheels not so much because they look pretty cool regardless.

If you have to get down to actual theory, most sources claim a 2 or 3% reduction in drag with the wheels. I've tested a mcgyvered rear wheel cover and it was about 1.5% improvement of total drag so a commercial product would be that or better. Somewhat better with the front wheel. Your speed increase would be less than the drag decrease (the v cubed thing)

airfoil71

Teaching in a research based field, I am aware of the placebo affect and it is a possibility. I also know there is some research that suggests that aero helmets can reduce wind drag 13%.. I do know, I now consistently ride 2 miles an hour faster than before I had the helmet and some of that could be psychological and better fittness but the biggest part of any sport is subjective in nature. The only concrete thing we have to go by is the data and unless my computer is broke, it reads two miles and hour faster. Also, the geometry of the TT bike puts more emphasis on the gluts and hamstrings rather than more focus on the quads. The gluts are by far more powerful than the quads and coupled with a very stiff bottom bracket equals better power transfer. Probably a combo of factors made the improvement... Just was looking for some input on disc covers.. I also understand that one glove does not fit everyone. I will probably give them a try, and maybe my mind will boost what they will actually do. I will take 1.5% plus the subjective end also.

furiousferret

Very true but it all adds up. There's a noticeable difference in feel with my aero helmet, disc, front 50 and skinsuit. Definitely not much faster if at all but you can notice the drag effects.

canam73

This thread could go epic.

merlinextraligh

The study that always gets referenced is from MIT, and it says an aero helmet is worth 1 minute in a 40K. That's way below 2mph. Moreover, I believe that was done using speeds higher than your 23 mph. Also, the actual real world advantage is likely less than the study suggests, when you consider the effect of how the rider holds his head (drop your head and the tail on the aero helmet may increase your drag) and differing wind angles.

I've done a fair number of TT's, (including a State Championshp) and I can guarantee you for me personally an aero helmet does begin to increase my speed even 1 mph.

wheelreason

I find my mind only goes where my legs will take it.

DGlenday

Click on this link!

It contains some of the best TT advice I've read, anywhere.

Hermes

You can lead a horse to water but you cannot make him drink.

I did the ERO Sports and the Alphamantis System at Velo Sports Center, an indoor 250 meter velodrome in Carson, CA VSC embed sensors beneath the track to create a system that would measure aerodynamic drag instantaneously as a rider rode around the track. In addition ERO Sports offers Retul fitting services. I had the opportunity to take part in the testing of the system along with the international teams, pro teams and olympians that were using the new system. I am not even close to that caliber of rider. I just asked if I could be a tester and they said yes. Horray!

I had a new Dolan DF3 track bike so I thought it would be a great way to get a Retul fit and then tweak it on the track using the new aero testing system.

Here is a link to a DC Rain Maker writeup who also took the service. https://www.dcrainmaker.com/2013/05/a...is-system.html

The most important consideration in aerodynamic improvement on a TT bike is body and head position. What is put on the body after that position is determined is a refinement that results in incremental improvement if done correctly. Not all aero helmets are created equal and it is the combination of the helmet and the body shape and position that will determine which helmet offers the lowest drag. The Bambino at $550 may not be the best one for you! In fact, it may be an older Giro helmet off of Ebay for $50.

If your head is up in the wind, you are dead on arrival. Round shapes offer the most aero drag. So the technique is to turtle ones head by lowering the neck and lifting the chin. This allows for forward visibility and keeps the aero helmet in the right position and the tip down.

Once one is in the optimized aero position, can you produce the same power over 10 miles - probably not. It takes time to adapt to a new position that can take weeks and months of strength and adaptation training along with base and a couple of build cycles. And it may not work for you at all. Some people cannot breathe properly due to the low position because it compresses the diaphragm. One way to improve breathing and chest / thigh separation is by using shorter cranks. The international teams are all going to short cranks.

A disc wheel and deep section front wheel will save some time in a TT but is it 10s of seconds. However, IMO, racing TTs is an incremental improvement game that takes months and years to perfect the ideal combination of equipment and position plus training to produce superior results. Good luck.

airfoil71

Kind of interesting, I have been into cycling for about 18 months and logged almost 12,000 miles and completed an English century and absolutely love it for competitive reasons and also for intrinsic reasons. I was a bodybuilder for 10 years and yes competitive but at the end of the day we shared information to help each other to achieve. I posted on here trying to get some input on disc wheels to see if they might help me obtain my goal and the majority of the responses were on the use of an aero helmet in disbelief or doubt. Theory and research are helpful along with formula's for success (https://www.bikeforums.net/showthread...ead-click-here) but experiences with disc wheels was what I was interested in.... For those who doubt the 2 mile and hour improvement, do not know what to tell you. The results with the helmet were both valid and reliable.. I appreciate the responses that gave their thoughts on the disc wheels.. Also, on a side note - I have learned that since making the original post not to post times and data information and the responses should not be as critical.

rkwaki

That's the 41 (Road Cycling Forum) my friend...
As both a cyclist and bodybuilder/powerlifter I can appreciate your post.
To put it in different terms it is like a guy saying he squatted 70 pounds more because he took a pre-workout drink... There is without question a placebo effect to what degree, no idea.

If you want a disc wheel get one, it may help but ultimately time, training, structure and focus will win you a tt.
Until you know for sure a Wheelbuilder disc cover will serve you fine.

airfoil71

Thank you sir, I have found a guy who will make me a disk cover for $70.00 and customize it.. I do believe the sum of the parts will give the best outcome. I also know most of the work lies with the engine and nutrition. Appreciate the response.

DGlenday

A related question ... would cling-wrap over a regular road helmet make any difference?

(I mean - besides making you look the biggest dork on the road )