Hi all, Hoping for thoughts on depth versus int/ext width versus weight of wheels and effects on speed for Crits. In particular depth vs width. If I can only choose 1, which is better for aero.
Recently purchased allez sprint for crit racing. Want better wheels. Might use bike and new wheels for odd weekend away or road race too. So not a climbing bike but not just use for flat crits. Looking at giant SLR0 aero wheels. 55mm deep, 1535g, 17mm int & 23mm ext. Local crits pretty flat but can have lots of surges. Weekends away can have rolling hills but nothing crazy. Im 95kg too. Another wheel in considering is only 38-40mm deep, 27 wide ext, 19mm Int, 25.5mm brake trake width but 1430g. So wider but not as deep. Which is better if budget won’t allow both?
The above wheels are narrow int and ext versus modern standards. How much does this matter vs 55mm depth and weight? I am wanting 2nd hand to not end up costing heaps so i cant just buy wheels that are light, deep and wide. But im not sure if these wheels are too narrow. Id run 25mm tyres minimum. I normally run 28’s on main bike. Are 55mm deep ideal too?
I realise some will state I’m overthinking it but i enjoy the details. Cheers
Edited to include new wheel option and refine core question to be depth vs width.
I would personally go for a wider internal width. Having bigger tires that are also aero for the rim is really nice.
As a rule of thumb I’d go at least 19 internal if you want to run 25s and something even wider like enve’s AR at 25 mm internal if you wanted to run 28-32 all the time.
I also think that 55mm depth is the best “all round” depth. We had to make this decision when we got our ENVE wheels last year and we choose Enve 5.6s.
I probably would have gone with 5.6 AR if they had it.
For pure crits or flat road races, I really like deeper 7.8 wheels (70mm front, 80mm rear). I think Pete is in the same boat as me.
The rule of 105. Basically, exterior rim width should be 105% of the (measured) tire width. Even 23mm tires would be too wide for that wheelset from an aero perspective.
Generally, the deeper the more aero. But additional weight and cross-wind issues. Anywhere from 40-55mm is reckoned to be good all-rounder territory.
Internal width is irrelevant to aero. But it does matter for tire shape while cornering. 17mm internal should run 25mm-30+mm OK.
I think wider is bettor but if you need a final tie breaker, it is nice if your primary and backup wheels are the same or close in width. (Assuming your not running disc brakes, then it doesn’t matter). It makes switching wheels easier generally and in a race the last thing you want to be doing in the wheel pit is fiddling while your brakes.
Thanks @Nate_Pearson! What are you thoughts if I can’t afford depth and width for crit wheels? (race what you can afford to replace).
Eg. Another 2nd hand wheel Im considering is a Parcours branded wheel which is only 38-40mm deep, 27 wide ext, 19mm Int, 25.5mm brake trake width but 1430g. So wider but not as deep as the giant SLR0 at 55mm deep but 23mm ext and 17mm Int. Which is better for aero/speed if budget won’t allow both? Depth or width? Does the lighter Parcours change anything for surges? Many thanks! LOVE the podcast btw! I’ve tried to listen to others but can’t get past the first 10min.
Thanks heaps for the info. Which is more important do you think from an aero speed perspective: ext width or depth?
Another wheel im considering is only 38-40mm deep, 27 wide ext, 19mm Int, 25.5mm brake trake width but 1430g. So wider but not as deep. Vs the 55mm deep but 23 ext width.
Thanks. Do you think wider is more important than depth when it’s 55mm deep vs 38mm deep and 27mm ext width vs 23mm ext width? The width will give more aero speed benefit? Cheers
I’m not sure. If you were a TTer I’d say depth, but there could be some cornering to be had on the 19mm. I think you’d be pretty good either way.
Maybe if you race on technical courses or in the rain go with the wider one. Dry and less technical courses go with the deeper one.
@Crazy_Joe_Divola just anecdotal but, when I switched from older narrow “V” wheels to the latest wider internal/external width I was pleasantly surprised. In my case it was going from the first gen ENVE (15mm internal and I think 19mm external) to the current set which measure 19mm internal and 29/27.5 external. It was like going from a Gatorskin to a GP5k. Just faster in a straight line and in the corners.
While not popular my answer for crit racing based on experience is the width (depending on what you are comparing) is worth investing in before depth.
Cheers mate. I bet you noticed a difference. That a big improvement in width as well as shape. 19mm ext is incredibly narrow. And then going to a 29mm! Must have felt a worthy use of funds.
I’m only tossing up a width of 23 to 27mm ext vs depth off 55 to 40mm. It’s not as large a jump so harder decision. But as Nate says, cant go wrong either way and may depend on what kind of courses.
I have the SLR0 wheels 55mm deep. I could definitely feel the difference going from the SLR1 30mm depth to the 55mm. I love the wheels for the price I got them for. Like others have said the internal/external width pretty much forces you to use 23mm tires. The 23mm Continental 5000 clinchers measure almost exactly 23mm on the SLR0 when inflated to 90psi. yet the 23mm Michelin Power Race tires inflated are just over 25mm. So finding a tire that is actually going to stay at 23mm is a challenge but the Continentals are almost perfect.
Thanks for the insights. I don’t really want to go down to 23mm tyres. 25mm is the narrowest I want to go for grip and rolling resistance reasons.
The question for me becomes do you think the SLR0 at 55 deep and 23 wide using 25mm tyres would be better aero/speed wide versus a 40mm deep wheel at 25.5mm wide at brake track with 25mm tyres? It’s 27 wide at widest part but I assume it’s the brake track width that actually matters.
I’m currently running 28’s on the 25mm wide rims for my everyday bike. It’s fine but naturally I’d rather wheels were 29mm wide.
https://www.hambini.com/blog/post/bicycle-wheel-aerodynamics-which-one-is-fastest/
If you haven’t read this it’s worth reading. The SLR wheels happen to be in the test. They mentioned a 23mm tire is the best aerodynamically on the front wheel even on wheels designed for a wider tire. They don’t take rolling resistance into account. The difference between the two wheels you are considering might be minimal and since you prefer wider tires it sounds like the wider wheels are better for you unless you wait and maybe come across a better choice.
Thanks mate! I hadn’t read that article and I loved it. It started my down the rabbit Warren of his YouTube too It’s made me think maybe I should go 25mm front and 28mm rear on my main bike.
It still doesn’t go into whether ext width & tyre matching is more beneficial than depth? I kind of thought he was hinting that depth was more important though? The shallower wheels are also 100g lighter which is minimal but maybe helps sway the decision to the narrower & shallower 40mm which are wider and lighter, even for crits which can be surgey.
You can use the Allez Sprint for rolling/hilly road races too you know. It’s not the bike.
Probably pick up some super light and aero tubulars too for sub 500$.
all in all, just don’t get too bent out of shape when someone drops you in a crit with their Aksiums We’ve all been there.
Oh yeah. The allez can do anything I want. I only talk about flat crits because that’s primarily what I bought the bike for.
And I’m not worried about being dropped buy someone on worse gear. There’s always someone faster than you with worse equipment. I just got moved up a grade in my usual crit and now my tactic is to not be dropped so that will be my world for a bit.
I would be wary of anything Hambini says. After reading through the whole mess on the weightweenies and slowtwitch forum, he comes off more as a snake oil salesman than an innovator. He throws in some well known truths, mixes it with his own commentary and spin then sells himself as a pundit. To me, it’s entirely possible he just makes up his wind tunnel results and unless he publishes a video with his processes I am inclined to not believe his findings because of his ratchet behavior.
I hadn’t read the weight weenies or slowtwitch stuff. Isn’t he just saying the stuff everyone else is? Depth matter but so does tyre width matching rim width?
Btw, how do I reply to you? I hit reply but it doesn’t visually show it as a reply as per why you did to me?
At the end of everyone’s post, there is a little reply button or you can highlight, then right click to quote.
Oh no no no. It’s way worse and childish. Basically Hambini’s response to any technical critiques or criticism is to fling verbal feces. It was all very weird to watch that train wreck occur in real time. There were odd and unsubstantiated accusations of lawsuits and all sorts of drama. See for yourself and come to your own conclusions. It’s too bad because initially it sounded like Hambini might’ve been onto something, but then he went off the rails.
It’s made me think maybe I should go 25mm front and 28mm rear on my main bike.
We’ve all been there.