A disc is a disc is a disc. Only experience I have is a homemade disc cover. Cost me $16 and a couple hours of frustration but works great. According to the sages here on ST they are all the same in the windtunnel.

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Jim

**Note above poster works for a retailer selling bikes and related gear*

There is little difference between a flat and a lenticular disc. Some argue that lenticular is better for beam bikes. For 99% of us, the fact that we have a disc in the rear is all that matters. Chances are you'll ride some courses where the Renn would be a second or two faster, and some where the HED would be a second or two faster.

Basically, other than cost, you and I wouldn't be able to tell the difference when we are on the bike.

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- Nick
Now that I know some of you guys look through the special needs bags for kicks, I'm gonna put some really weird stuff in mine. I can see it now. "What the heck was he going to do with a family pack of KFC chicken, a football helmet full of peanut butter, a 12 inch rubber dildo, and naked pictures of Bea Arthur?"

renn five seven five is way cheaper than the hed disc.

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"The aspect of sport that you learn is that you have your good times and your bad times, but you share it with great people." - George Gregan

It's not way cheaper, you can get the Standard Hed for $500 as opposed to $450 for the Renn.

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Portside Athletics Blog

500 british pounds

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"The aspect of sport that you learn is that you have your good times and your bad times, but you share it with great people." - George Gregan

http://estores.merchantpartners.com/...1bdb1e89d06837a24ea7

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Portside Athletics Blog

http://www.hedaerolab.com/pdf/hed_price.pdf

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"The aspect of sport that you learn is that you have your good times and your bad times, but you share it with great people." - George Gregan

All this linking to other sites, if you look at the Renn site (www.rennmultisport.com), the price for a 575 disc is $450, on Hed's site (www.hedcycling.com) the price for their standard disc is $550.

I ride an older Renn 575, and it's faster than a standard spoked wheel. I doubt that I'd notice any difference with the Renn vs. Hed shape. The Renn discs are fairly bombproof, can't speak to the quality of Hed's. Frank Rehnalt (owner/maker of Renn discs) posts on slowtwitch and is a triathlete. Steve Hed, of course, is the aerodynamic guru for Lance Armstrong and company. Both, I think, are likely very good disc wheels, and either way I think you'll be happier, and faster!

For my own money, I'll go with Renn, as I've been happy with the product and Frank has always answered my questions in a timely manner in the past. Good customer service is worth a lot to me.

Chris

The HED disc is ridiculously heavy. It is like .00001g of drag less than a flat disc. The extra weight definitely costs more than that.

There is a reason that the USPS team rode on H3's, but never on HED discs...

Get a Renn. Lighter. Cheaper. Better.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

Thats an easy one.

Renn, lighter, CHEAPER, just as fast as you legs can go ;-)

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S�rgio Marques
When it hurts is when it feels good ;-)
Sergio-Marques.com

Now that you all have convinced me of the merits of the Renn disc over the Hed, if I was only going to have 1 rear race wheel in my collection, would you recommend an H3 or the Renn disc. I have an H3 front and am looking for a fast rear, but it has to be versatile as I can only afford one. And for the sake of the discussion the H3 is used and will cost me ~$300.

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Portside Athletics Blog

in the last year i've purchased, installed, and tested both the standard HED and RENN 575 discs. the RENN, without hesitation is the best bang for the buck IMO. in not only product but also constomer service. the HED disc, i purchsed new directly from HED was more expensive, heavier, and not true (sp). to sum up a long story, they (HED) had very poor customer service. bonus on the RENN: i use a valve extension to simplify the tire inflating process, where as the HED i needed to purchase a separate (can't think of the correct name) crack pipe to inflate the tire (which was a pain in the @%^). hope this helps....

SwBkRn44,

I first purchased a pair of Hed3 trispokes to race (time trial) on. A year later I purchased a Renn 575.

Handling: I have found my bike to be more stable in cross winds with the rear disc and front trispoke than with trispokes front and rear.

Speed: I am convinced the disc is faster than the trispoke but how much so I cannot offer.

Coolness factor: The disc is way more cool than the trispoke. The disc identifies you as someone who has the wit to recognize a disc is faster in almost any situation. And the resources (money or friend who lets you borrow his disc) to be a serious racer.

What I have found is that I would use the disc always over the trispoke on the rear regardless of the wind. If it were so windy to cause me to not use the disc, I would not be riding because it was too windy. To quantify these conditions, I mean crosswinds in excess of 40 mph.

The caveat: A racer on a bike with a disc who is creeping along the course because he is incapable of riding fast is the ultimate poser. This is not to be confused with a serious racer who falls apart (blows up/bonks).

If you are not a fast rider already, a disc will not make you that much faster. Certainly, it will not permit you to go 5 mph faster. If this is your case, save your money. Spend it on a good set of training wheels and go out and ride, ride, ride. Then invest in your engine. This is where you will make your biggest training gains and increases in speed. When you can maintain a 23-24 mph ave speed for 10-25 miles, then you can think about the disc and what it might do to help you shave a few more seconds off your time.

We all have seen the 16 mph rider on the $5,000 bike we wish we could afford. If one has enough money, then one can spend it as one wishes and can do things because one has the means. Riding a disc can fall in the same category.

For some, the $5,000 bike motivates them to ride more and to ride faster andbegin to improve and get better. I have never seen this to be the case with a disc wheel.

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Ben Cline


Better to aspire to Greatness and fail, than to not challenge one's self at all, and succeed.

Care to elaborate on that? It goes against almost every other post on the excellent customer service provided by HED.

a disc fits 95% of triathlon courses, at least the draft free tri's. Draft legal is a bit diferent.

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S�rgio Marques
When it hurts is when it feels good ;-)
Sergio-Marques.com

Ben,

Thanks for the reply, I have heard what you are saying from other people as well, that a disc in the rear actually handles better than a tri spoke. I trust your opinion, I am just wondering why? Shouldn't a disc by it's nature be more susceptible to winds? Thanks.

Mark

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Portside Athletics Blog

To hazard a (somewhat educated) guess as to why a disc is more favorable in the rear than a trispoke:

You don't have to worry about torque the same way as in the front (no pivoting fork), so it is not like a disc can twist your rear end around. There is rarely (if ever) a pure crosswind. In a pure crosswind, a trispoke would be probably be more stable, just because of less surface area. Kona may be the exception, where the surface area really could cause you to get blown over just because the wind can be SO strong. But in most wind conditions, a disc may smooth the airflow better than a trispoke, resulting in cleaner airflow around the back of the bike, making for a smoother ride.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

thanks for starting this thread. I'll be getting a Renn disk because of it!

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-zakk

Death Squad Cycling Club
http://www.ridethedeath.com


"Why is that people will drop $2000 on race wheels and a few c-notes for an ugly tattoo and then balk at the race fee?" - Blackie

If you've already got a pretty lightweight wheel, you can get much more affordable than the CH Aero wheel cover.

I bought one from wheelbuilder.com to use on my Mavic CXP33 rim and PT SL hub. The cover itself weighs about 380 grams and attaches with a set of plastic screws around the edge. You have to remove your cassette to put it on, but the whole process is pretty painless. Rich at wheelbuilder will trim the cover to fit just about any hub/rim combo you specify. Trimmed for my rim and the PT hub, it cost me $80. Oh, and the cover shape is lenticular (pretty much has to be since it's covering the spokes).

I took my first ride with it last night and performed a semi-scientific test. After warming up, I did a 5-mile loop without the cover and then the same again with the cover. Despite putting out 8% less power on the loop I did with the cover on, I was still 5 seconds faster over that 5 miles. I didn't put out a significant effort on either ride. With my rudimentary understanding of wind resistance, I assume a faster pace would have resulted in even more savings. Granted this was one trial and I have no comparison to the gains that might be had with any other disk, but it was still cool to see less effort=more speed.