Tuesday, May 10, 2016

Giro Empire SLX Review - Fastest Wind Tunnel Tested Ironman Triathlon Bike Shoes

Photo Credit: Tim Hughes
This past March I forked out $1,000 of my own money to visit the A2 wind tunnel. One of the things I tested were my old Pearl Izumi Octane shoes and a new pair of Giro Empire SLXs. The results were absolutely shocking!!!

Before I go into details, let me explain a little bit of my philosophy when it comes to equipment. Simply put, in the absence of an aerodynamic design or aerodynamic data, I go with whatever is lightest.

My previous Pearl Izumi Octanes were light, sub-200 grams, but with two straps they didn't seem very aero. I had talked with friends Sebastian Kienle (Ironman World Champion) and TJ Tollakson (Ironman Champion) about shoe covers that tested fast for them, but the problem is they are not practical to put on in the middle of a race. Although fast, TJ's were custom tailored just for his shoe and foot.

Dreitz 3/8inch ~9mm Elastic 
Luckily, I came across the new Giro Empire SLX shoe. It is a traditional shoe with laces and it seemed like it could be aero. Being a triathlete, I immediately thought I could re-engineer them to use elastic laces.

With a Giro Empire SLX in hand I went ahead and got to work tinkering with the shoes. In the end, I decided that the best thing to do was cut the tongue from the shoe. For me, someone who is doing a flying mount in T1, cutting the tongue is a necessary as the tongue will bunch up when you *jam* your foot into the shoe in a race.

I also experimented with lace width. It turns out that traditional elastic laces are too wide so I bought some regular Dreitz elastic in bulk that is the most narrow I could find. It lays flatter for better aerodynamics. The end results is a super light shoe - 162grams for size 9.5. Is super comfortable, yet stiff, and super easy to get into and out of. Note, I drilled a hole in the back so that I can slip a rubber band in them in transition.

My old Pearl Izumi Octane and prototype
Giro Empire SLX with elastic laces
Desipte the Giro Empire SLX being a superior shoe in all regards to the Pearl Izumi Octane, I still needed to see if it was faster aerodynamically speaking. It turns out that it was. In my wind tunnel testing they tested 4 watts faster at 0 degrees of yaw, and 12 watts faster at 10 degrees of yaw!!! This is at the industry standard of 30mph.

After a full year of racing in the shoes I am still in love and had my fastest bike splits yet. I am in no way supported by Giro but if you are considering purchasing please do so thru the links below. Doing so helps to support my own tinkering, testing, and writing for all!!!

Additional Resources
- Giro Empire SLX on Amazon
- Giro Empire SLX on eBay
Giro Empire ACC - less expensive version of SLX
LG LA84 - very inexpensive set of lace-ups by Louis Garneau

Since publishing this many pros, including Matt Russell, AJ Baucco, Michael Weiss, Kirsty Jahn, and Cody Beals have been seen on the Empire SLX. Each has their own unique modifications done to the shoes. 

Photo Credit: Tim Hughes

Future Ideas:

So many amateurs and professionals have made their own modifications to my standard elastic design. I wanted to highlight two potential products that some have been using that I like and will be experimenting with in the future.

Xpand Laces w/ plastic tabs - Xpand laces are regular elastic laces but have a special plastic tab to lock in the lace without knotting the ends. This allows for riders to play around with lace tension while they figure out what tension is best for them without wasting lace and dealing with knots.

Xpand laces with plastic tab for future adjustability 

Inmaker Flat Rubber Laces - I had tried Riplaces w/o success but this design is a little simpler than Riplaces and has potential to work.They have different sizes to accommodate desired tension. One complaint about elastic is that the laces tend to get twisted and don't always sit flat. The idea behind these is that they will sit flat.

Flat Rubber Laces



72 comments:

  1. I'd be a little concerned on a hilly course. with the elastic and pulling up????

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    1. Harry this isn't really any issue. Fwiw I did Wildflower and rode up nasty Grade in a 54-32. This seems to be a common "thought" problem but based on practical use is not a concern IME. This comes from a guy who rides Powercranks and actually uses his upstroke. The typical triathlete at best is unweighting the foot. I have no reservations.

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  2. where did you get one thousand dollars?

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    1. I actually had a full-time career for most of my life selling medical devices as 24-7 on call medical device rep, but yes it was investment, hopefully it will help me make more than the $1000 in the future.

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    1. Negative on BOA laces. I have had BOAs, not desirable. First you are going to have to keep the tongue in. Wire will cut up your feet. Second there is no benefit to them. With elastic it is easy to slip your feet in and out of them. The beauty in putting you feet in you just jam your feet in. The elastic will find its way in to the proper position eventually on the bike.

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  4. Glue on a piece of neoprene like the material used in velotoze over the whole lace assembly - kimda like a shoe tongue, but on the outside- and you seal the whole thing up and probably find another watt or so! Kinda like the bont aero shoes.

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    1. Not a bad idea at all - thanks for the idea :)

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  5. I wonder how zip up shoes would do. I am for less drag, but we have to consider speedin and out of transition

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    1. Zip up shoes is not a terrible idea. I think the hard part is getting the fit right. Would surely have to be a custom job.

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  6. I think Sebastien's orca shoe covers can be put on the shoes beforehand and still transitioned into (without having to put them on)

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    1. I will talk to Sebi next weekend at Chatt 70.3. He doesn't wear the covers in every race for a reason. The last time I saw him wear them was his win at Frankfurt so I will find out what the deal is with other races. Thanks for reminder :)

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    2. Keep us posted!. Would be interested in when/what covers work for the PI octane since I really don't want to buy another new shoe

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  7. I'm thinking the Louis Garneau LA84 could be the poor man's version of this, no? Definitely not as light, but < $100 and seems to pass the eyeball aero test!

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    1. Definitely another option. As they stand they are about 180grams heavier, than Empire SLX. As my Empire SLX are modified they are about 200 grams difference or nearly 1/2 a lb

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  8. I had the same thought after watching the Specialized Win Tunnel episode on shoes: https://www.youtube.com/watch?v=NtHdsNxCkjk&index=2&list=PLcmaLnqmqDnmn_bCR0RJ-soSCDKCKR97t

    Tried some of the LA84s on today.....fit true to size, but rounder toebox and wider midfoot then my Sidis.

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    1. Shape of the shoes is definitely going to matter. In general the small frontal profile the better, but a better shape could make up for the difference. I also just re-watched the Sub6 Specialized video. Good stuff.

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  9. so how will u deal with ventilation after the pee goes down your leg into the shoe? hehehe

    specially on the giro shoe

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    1. In all my racing I think I have had to pee once on the bike.

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  10. I just bought the slx and got the shoelaces off your link :). Thanks for the recommendation. I expect this will give me course records everywhere I go :)

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    1. I appreciate that!! Giving u some PR karma :)

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  11. Hi Thomas,

    I race draftlegal races.. When you say fast entry, do you mean ITU fast? Would be pretty awesome to rock some white sub6 shoes with laces :)

    Best regards,
    Lars

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    1. Lars I would love your feedback personally. With the elastic I mean you can just jam your feet in there and the elastic will give and find its places. At the very least you don't need to worry about bending down to open up them to release coming off the bike. Just pull your feet out. That is at least one last accident right there.

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  12. Is this idea still alive? Picked up a pair of empires and I'm thinking about using riplaces so I can individually tune the entire shoe. Thinking of DIY rubber covers to add, similar to the sworks sub6. Ideas?

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    1. Dan, this a reality not an idea. I now have 10 races on this shoe this year and many other pros have done the same thing. I liked the idea of riplaces but they didn't work for cycling shoes in terms of being able to get in the shoes quickly. The elastic is the way to go at this time although I will still be playing around with riplaces as well. No plans for DIY rubber cover, I am not sure it adds anything of benefit. I would like specialized to test their sub6 without the cover and with some flat elastic laces, I think they might be surprised.

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  13. Thomas,

    How are getting in the shoes when you do a flying mount or do you put them on in T1 and then clip in? Do you keep the shoes upright with a rubber band? if so, how? Getting out of them is probably easy, but I imagine getting in them is the challenge.

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    1. Getting in them is just as easy or easier than any other shoe I have ever had. This is why cutting the tongue out is necessary though as it will bunch as you try to jam your foot in. Elastic is important as well. I have a hole drilled in the back and I slip a rubber band thru just like normal Tri shoes.

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    2. Great info. Follow up question. How did you cut the tongue out? Did you de-thread the tongue at the base or did you cut the tongue some other way? Just ordered a pair and prepping for "Shoe Surgery"...

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    3. I did a hack job and just cut the tongue out near the base with a pair of snips.

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  14. Hey Thomas, Did you use the 3/8" wide elastic you referenced, or did you use a narrower version? And how did you guide it through the eyelets? Thx

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    1. Yes, I used the 9mm, I might play around with wider too and maybe cut some slits in the eyelits to allow wider lace to lay flat. As for as poking thru, you can take a match the ends and create a nice stiff surface to guide the lace thru the eyelets. Hope that helps :) -TG

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  15. Thomas, did you test the ACC? Thoughts on aeroness of either? I see venting on the SLX that may be helpful in that it creates turbulence, or it could be the opposite and that the ACC is faster

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    1. I did not test the ACC. I do believe that the straps, and hard lips/ridges are what create the drag. That could be wrong but 80 grams of rotating weight like shoe is not going to be the same at 80 grams of static weight. Someone could do the calculation.

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  16. Hi TG,
    What are your thoughts on the Bont Cronos? They look super fast but quite expensive. If you put elastic laces underneath the "aero cover thing" do you think that would work?

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    1. Michael,

      Thank you for the question. I think the Bont Cronos would work. They are quite a bit heavier. Not testing the aeroness of them I can't quantify how aero they would be. I do believe that part of the SLX being light also means they have less material, which means they are not a bulky and could possibly lead to a profile that is smaller to the wind. Obviously shape is a big deal in that too. I know a few other pros that have adopted the Bonts including Jan Frodeno, Andy Potts, and Taylor Reid.

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  17. Hi Thomas,
    Thank you for the insight (as always). Question regarding entry into the shoe if I may: any issues sliding the foot in after a flying mount? I noticed the absence of a loop on the heel and was wondering if you had any issues sliding the foot.
    Many thanks
    Mischa

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    1. Do a search for Kirsty Jahn on facebook. She has some elastic loops in the back of hers. I don't just because I don't know what kind of drag they create. For me, it is note a problem getting in the shoe, but you can always add a elastic loop. She drilled a small hole in the back of her shoes. Hope this helps. Happy tri-ing!!!

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  18. Hey Todd, you still swearing by these Giros? Just thinking of pulling the trigger on them since everything here makes sense and wanted to make sure there wasn't something else you've found since last year. Thanks!

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  19. I actually bought a second pair myself. There is nothing better than this shoe that I am aware of.

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    1. Let the surgery commence! Thanks for all the insight and direct, quick replies. Helps a lot. Good luck in 2017!

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  21. Hi Thomas!

    Such a great article on these shoes! would your elastic lace mod and tongue cut mod be the same for the acc? im not doing a flying mount anytime soon so wondering if cutting the tongue is really needed for me. and last question, doing HIM or even going out for longer rides would you be concerned with your feet swelling? thank you!

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  22. Thanks for the kind words. If you are not doing a flying mount then feel free to keep the tongue. I haven't any issue with feet swelling being an ISSUE. Elastic laces do limit some flexibility in that regard. Laces tend to stretch a bit over time too. You can certainly get one of the plastic fasteners so you don't need to "semi-permanently" tie a knot and then have the flexibility to let out some lace if your feet do swell too much.

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  23. So I bought the stretchy laces. How did you ever thread the laces through the shoes?

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    1. Joe, Thanks for the question. You can either burn the ends or you can simple use like a wire and thread the wire thru the lace then pull the wire thru eyelet and the lace will come with it.

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    2. ahhh. I see now. Makes total sense. Love the blog, keep up the great work.

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  24. Hi Thomas,

    I was just wandering, how did you cleanly tie the ends of the laces like you did? I've ordered some flat laces like the ones you described above, i was thinking of trying out the lacing in a reverse order, i.e tie at the bottom, have you tried this? I was thinking it might make flying mounts a little easier having some elastic at the top you can tag at care free.

    Thanks,
    Owen

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    1. Owen I have seen so many different lacing styles from all the people now running these. I don't think there is any pattern that is the absolute best. I just tied to 2x knots per side, then cut of the excess, and burned the tips to remove all the fluff and excess that the scissors couldn't do with.

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  25. Great i'll give that a try, thanks for the help!!!

    Owen

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  26. Do you think the Sub 6 will give the same kind of gains without messing around with the cover? I have used the Specialized "Body Geometry" shoes for some time and am reluctant to switch.

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    1. They are very similar shoes. I can't imagine there is much of a difference between the two.

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    3. Thanks, I'll give these a try with your elastic lace set up.

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  27. So I got the shoes and did the doctoring and I love them! They feel awesome and stiff as hell.
    The only issue I'm having is getting them on if I leave them on the bike in transition like I like to do. It's hard to slide my foot in with 1 hand while pedaling because the sides pull in and the opening is really narrow. Any trick you've found with this?

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    1. Todd,

      Practice, practice, practice. I would spend an entire hour just dedicated to practicing mounting and dismounting now, and maybe another 15 mins every month. In addition you can always place a heal tab on the back as well and adjust the tension of the laces. As an Ironman athlete I have to adjust for feet swelling over a 5+ hour race and you only have one shot at tension so better too loose than too tight.

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  28. Thanks for your input on making the Empires into tri shoes with elastic. I just dropped $9 on Amazon on Xpand laces and they seem be pretty solid. Too nervous to cut the tongue out but even with the tongue it takes about 5 seconds to get each shoe on, I'd highly recommend the setup!

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  29. Can you describe the toebox of the SLXs? Wider like the old Carnacs or narrow like Sidis? Thanks, Matt

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    1. Unfortunately I have never had a pair of Sidis. What I am told from people, I have normal width feet for my height, is that if you have wide feet these might be a little cramped.

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    2. Thanks for the quick reply!

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  30. Any chance you could post a photo to show where you drilled the hole please.

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  33. I did yes. Others have turned it into zippered shoes, some have cut part of the tongue out and had the remaining tongue stitched. All kinds of options. The purpose of the tongue being cut is if you try to do a flying mount in triathlon the tongue will bunch at the bottom so you have to cut it or do something else with it. If not doing a flying mount you can leave it in.

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  34. Do you feel your feet come in/ out slightly when you are in the standing pedaling position?

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    1. I think it depends on how you set them up personally. You can make them as tight or as loose as you want. You can cut the tongue out or leave it in. There are + and - to each approach. Do my feet come out while standing, frankly no, but I don't do a lot of standing climbing either, I usually try to stay seated and only get up to take some relief off my bottom. Are they as locked in as tightly dial strapped. Definitely not. But I have setup to be able to pull my feet out of the shoes at the end of the bike so I don't even need to reach down if I don't want to. I do think people should have two pairs, one for racing and one for training. You can keep the regular laces in for training if you would like.

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  35. I have followed the discussion with interest. Newbie older triathlete still learning intricacies of biking. Have to agree with practice practice practice. It made a huge difference finally with flying mount into shoes fixed into pedals. I am a diehard SpeedPlay pedal user, and that drastically cuts down the choice of available shoes. My prior go to is/was SIDI T3.6 Carbon Air, and I fine tuned it so it works great. But following your thoughts, I weighed the shoes and they are heavier than I like, and of course the super Tri-friendly Velcro straps are horribly wrong for Aero. So I have to re-think. The lightest SP shoes I can find are Vittorio EVO SP Carbon, and they are laced shoes -- maybe that's part of the reason why they are the lightest -- but they are still 60g per shoe heavier than the GIRO Empire SLX; I doubt cutting the tongues out will lighten them much, but I have to live with that.

    My question is regarding the pre-setting of the elastic. My understanding is that you have no provision for adjustment while on the bike -- you slide them in at whatever tension you have pre-set, and ride on with that same tension, is that correct? I have some experience with elastic laces on running shoes -- they have a slide adjuster, but I find at the right tension sweet spot I can slide the shoes on without needing to change the tension to go immediately on to the run. But in this situation I still need to use my hands to help the shoe on and to help ease my heel over the the heel lip. I can't visualize a situation where the elastic would be loose enough to slip in the foot with no hands. The way I have my SIDIs, the velcro strap is set in a huge open loop, and the foot slide in is a slam dunk, then I reach down and tighten the velcro -- but your set-up is tight enough that after slide-in no re-adjustment or tightening is necessary, correct?

    I think I have to re-think my concept of how snug the elastics have to fit for efficient pedalling, or else practice much harder to learn to smoothly slide the foot in without hand assistance into a rather snug elastic fitting. While sliding in do you have any trick of lifting the heel to stretch the elastics so that your heel has more clearance over the heel rim of the shoe?

    I am anxious to learn your technique. It seems way slicker than to require some further engineering like putting in a zipper beside the elastic lacing.

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    1. I'll admit, this post greatly exceeded my original thoughts on how popular it would become. I think the key thing for people to understand is that when you are racing you often use different equipment than training. The quintessential example of this is tires IMO. Race day rubber is very much a real thing, but there are always sacrifices with race day rubber.

      When it comes to aero shoes with elastic you only really get one shot at tension for race day. Sure you can fine tune it later if it is too much or too little, but I still recommend people have racing shoes and training shoes. Racing shoes are going to get beat up if using for training and I believe that negatively affects the aero performance of these shoes.

      Finding tension balance is important but there is no right or wrong answer and is a matter of preference. I have't changed my tension since I first installed the laces after some initial playing around and it works but I know it isn't going to work for everyone. While I am anal about somethings, I am also super relaxed about other things that others are really uptight about. The reality is that riding super flexible soles in training (think cheapest road shoes you can find) I have learned that stiffness is just not a problem. Better to be too loose than to tight. Losing watts is not a concern, yet people for some reason get fixated on it. It is often these same people that have been huge opponents to things like PowerCranks which emphasize that backstroke/pull-up when we know very little force is actually generated in the backstroke in the first place.

      As for getting them on every shoe is going to have their quirks. Shoes with straps you have to get your feet in then close the strap. You also have to open the strap to take off. With practice, a quick grab of the heel is all I need to slip on the shoes but others have added bigger heal tabs and have lots of other innovation as well. Heals tabs are not going to be as aero though.

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    2. From the viewpoint of a Newbie who has thought about it a lot, from a practical viewpoint, it is indeed too expensive to be using your top-end equipment all the time for training, particularly the equipment that by its very nature degrades quickly or is a consumable. However, in the case of shoes, you have to be very careful when training in your cheap shoes if they are very different in technical requirement from your race shoes. Particularly if you have fine-tuned the race shoes in terms of weight and aerodynamics, but the price you pay for this improved performance includes the need for perfect technique (flying mount onto pedal mounted shoes) with very little forgiveness for error. Unless you set aside some time before the major races practicing mounting and dismounting (and checking for correctness of adjustment of the laces) in your race shoes you are setting yourself up for a setback, if not a disaster resulting from imperfect foot-security within the shoe during the chaos of the bike start out of the transition (think Simon Whitfield at the 2012 Olympics when he hit a speedbump before his foot was into the shoe properly, fell and broke his collarbone). Perhaps another solution might be to get elastic laces onto your training shoes, so that you are constantly practicing with this kind of shoe, although the specifics of entry into your race shoes would require at least some pre-race run-throughs with those actual shoes.

      You mentioned the PowerCranks, which you are a proponent of. If one is not transmitting significant force on the back-stroke, what is the benefit of training with Power Cranks?

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    3. Sorry I wrote a really long reply but had a Windows BlueCode and lost it all. In short...

      The reality is that you can't replicate racing in training and the nerves that come with it. The Olympic's have even higher stakes. While you can practice practice practice (which I do), the reality is you will never have that same adrenaline going thru your body. I don't recommend Flying Mounts for Newbies in general.

      I only have one pair of triathlon / cycling shoes at the moment. Unless you count the pair that is super cut up so I could squeeze my foot into my shoes while cycling with a broken toe. The elastic tension works for me, but my response to people that are nervous about slipping or not being tight enough for training is that they buy two pairs of shoes. The reality is that while elastic has some give, strap shoes don't and your foot changes in a race, especially longer hotter races where you feet my swell. Elastic, while you can't make big adjustment, like reaching down and opening the strap, the elastic can expand and contract. Straps don't do that but you can make big adjustments.

      A second pair of similar shoes, you can leave the tongue in which helps with comfort. And you can put a elastic pinch enclosure on to allow adjustability of laces on the fly. You can even do this on your race shoes but at the downside of being not as aero.

      As for PowerCrankz, that is a whole book on itself and it comes down the body, imbalances, the quads, hip flexors, and hamstrings ultimately back to the hips where everything starts. While you don't generate nearly the force as with the quads, Powercrankz reinforce the unweighting of the "non-pushing" foot and you still do engage the hamstrings and cause more muscle activation which is a positive. Regardless of whether you believe pedaling in circle is important as a road cyclist/triathlete, try telling that to an MTB who pedals in thick sand.

      THE BIG REGARDLESS here is I always caution anyone going out to compete and have fun, to spend less time going over the details and more time training. There is a time and place to start working towards the details but the fruit is much higher up and not as big as the low-handing fruit most Newbies can get by training more.

      Anytime you do a DIY project you are going to spend more time than if you just bought a complete off the wall solution. There is a reason why Giro Empire SLX come with regular laces as opposed to elastic. It allows adjustability at a moment's notice.

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  36. Het there Thomas, have you seen the DMT pista track shoe which is a lace up with a Velcro cover seems very aero visually

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