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    Senior Member waynesulak's Avatar
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    Interesting Zip 808 Review and What about those dimples anyway?

    I read a lot about aero wheels on the Tandem Forum so I am posting some quotes regarding Zipp Firecrest wheels from a top British amateur rider’s blog that I read. First to give some perspective regarding the type of rider he is below is a quote from an earlier entry:

    Getting overtaken in a time trial
    By tejvan on July 18, 2013 in cycling

    It’s not too often I get overtaken in a time trial, so when I do I tend to remember it. I remember once in the 2010 British Time trial championship. I was happily speeding along at 33mph on the flat. I was feeling pretty pleased with myself when a Sky rider came past like a steam train. I didn’t even recognise the rider. If I was going to be overtaken, I would have preferred it to have been at least a Wiggins or somebody with an Olympic gold medal. So a few years later, I can feel a little better that at least I got overtaken by a future Tour de France winner. That race was probably the first time I heard about Chris Froome. He ended up finishing 2nd – 1.22 behind Bradley Wiggins. I finished 24th – 9:18 behind Wiggins. 7 and half behind Froome.

    Some people have commentated that before 2011 Froome was no good at time trials, but that was a pretty good result – given Wiggins was on top of his form. Anybody who puts 7 minutes into Pettinger must be half decent in my book.

    In retrospect, it was probably quite an important result for Froome. 2010 was a disappointing year – plagued by illness, he had few results to show. The British time trial championship is pretty low key in the grander scheme of things, but the time was probably a factor in encouraging Sky to stick with him.

    I’d love to have another go in 2014, and compare my performance. I reckon if it was hilly enough, that on my current form I would get quite a bit closer than in 2010.

    After the race, I went back to take some photos of the elite riders finishing. I got that shot of Froome and Andy Tennant, and also this one of Wiggins and Hutchinson. That was a pretty luck photo. On the ride back to the HQ, Geraint Thomas came up to chat and he was very friendly. It was a good experience to have riding against the pros.
    That race was the first time, I had to report for a dope control. My number came up on the random choice board.
    Now his comments regarding a recent purchase of a Zip 808 front wheel:

    Zipp 808 Firecrest review

    By tejvan on July 19, 2013 in products

    I’ve had a pair of Zipp 404 since 2006. They are a good versatile wheelset. They are lightweight 1,250grams – so I was able to use in hillclimbs for several seasons (Until I got some Zipp 202s), but the deep rim profile is also aerodynamic. 404s are a good all rounder. The Firecrest 404s are said to be a significant improvement on the old 404s.

    I decided to get a Zipp 808 Firecrest front wheel because
    • Aero tests suggested there was less drag on a Zipp 808 Firecrest to my old Zipp 404 front wheel.
    • It’s one potential marginal gain for quicker time trials.
    • I haven’t bought a new front wheel for time trialling for seven years
    • It looks good. (the least important of course, but it does look good.
    • Amazingly I had the necessary 850 in the bank account

    Front wheel 808 Firecrest
    • Weight: 745 g (including skewers). Note I’ve seen different weights advertised, but that’s what it weighs on my scales!
    • Rim depth: 82mm
    • Max width: 27.5mm
    • Spokes: 16

    The first observation about the wheel was that I had to adjust the brakes. The rim is significantly wider than most standard wheels. The rim profile is 27.5mm) The wheel didn’t actually fit into the brake blocks when I first tried to put it in. This was a bit irritating. I often swap wheels when training. I’m not keen on having to adjust brakes every time. Secondly, it seems counter-intuitive to improve aerodynamics by increasing size of wheel.
    Zipp claim that Firecrest is the first aero profile that effectively controls airflow around the back half of the wheel. They do this by maintaining a near constant width all the way to the spoke bed. I’ll have to take their word for it.

    I’ve ridden in two time trials. The YCF 50 (new pb of 1.45 (taking 6 minutes off pb) and Nat 100 (new pb of 3.46 – taking 6 minutes off pb)

    So it’s a pretty good record. Two races and two personal bests of taking 6 minutes. However, I’m not attributing all that to the new wheel. (I also bought a new Zipp discwheel – more on that later) Of course, it’s really hard to say how much difference the wheel made.
    But, it felt fast.

    Aerodynamics

    The chart which got me to part with 800 for an 808. How much can you trust manufacturers wind tunnel tests?
    Other points
    • It makes a good sound when riding
    • I haven’t tested the Zipp 808 rear wheel, but I’m sure it would be a good ride. With rear wheel you don’t need to worry about crosswinds. I nearly always use dischwheel when time trialling.

    Control

    In both races the wind was quite low. Over the 150 miles there was a mixture of light headwind, crosswind and tailwind. In the National 100, there was a dodgy moment when I got a blast of air from a big lorry going the other direction on the single carriegeway, there was quite a bit of movement in front wheel, the loss of control took me by surprise. I’ve never had that kind of difficulty handling on a 404 in the past seven years. This wasn’t isolated, I definitely felt the difference in handling between 808 and old 404. Zipp claim 808 Firecrest is as stable as old 404, but that’s not my experience.

    Fabian Cancellara is said to use Zipp 808s even in road races, so it shows other people might have different experience (Note Fabian Cancellara has about 20kgs more ballast than me)

    Braking

    The front wheel surface has been improved for braking. There is a resin which helps resist heat It feels solid and gives nearly as good performance as aluminium surface. Zipp included a free brake pad. The downside is that (like most Zipp products) if you want to keep using Zipp it’s expensive to replace.

    Conclusion

    If you had to buy one set of wheels, I’d definitely go for the Zipp 404s. The Zipp 808 front wheel is really a specialist time trial wheel. I was slightly perturbed at the difference in handling between a 404 and 808. The 808 is definitely more twisty and can get caught be a gust of wind. I’m a light rider (62 kgs) so don’t have same bulk, but I would be wary of using the 808 front wheel on a windy day. It’s taken several years to justify making the upgrade from 404 to 808. But, I’m happy so far, even if it is a big wad of cash to splash out.

    One question if the Firecrest dimples are so good, why do Zipp cover up 40% of them with big stickers? Do the stickers not slow down the effect – if so why put them on?

    Zipp 404 vs Zipp 808

    The Zipp 808s are heavier than the Zipp 404s by about 200gram a set, so it is not good for mountainous terrain. I would be wary of riding in strong crosswinds because of experiences so far. However, I am pleased with raw speed of this front wheel, so it’s good for time trials.
    Last edited by waynesulak; 07-30-13 at 11:52 AM.

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