Mixed Wheel Rim Depth - Does it work?

Hi all

I’m looking for some opinions here from folk that have had experience of both set-ups.

I will be buying carbon rim brake compatible wheels shortly. Ideally I’d be going disc but currently my bike and budget will dictate that it’s rim brake wheels only for now!

For the 3 1/2 years I’ve had my Canyon Ultimate CF SL I’ve been running it on the as bought Mavic Ksyrium Elite Wheelset.

I want to go a bit aero and a bit lighter. My riding will be mixed, doing the Etape du Tour this July, I live in the Scottish highlands where there are plenty of climbs, it can be windy and I will also be using the wheels for rolling road races too. I know, it’s a real mixed bag.

I had my eye on some Scribe 38’s…

Then I came across the idea of mixed rim depth with 38 front and 50 rear…

I’m really looking to see if there is a real benefit in a larger rear rim depth and a shallower front, I know most benefits would come from the front depth but my general riding requirements will not need that based on my description of that at the start of this thread, wind, climbing etc.

Is mixed depth just marketing hype?

Appreciate any feedback.

Cheers!

All I can say, as 51kg (currently during winter 53kg) tiny rider that I have never, ever had any problems using 50mm rather retro V-shaped front and rear, regardless of the wind speed, my speed, downhill slope and anything else.
Of course wind affects handling - the same way it did using my shallow, alu, lightweight old set of wheels. Seriously, no difference other than the sound of the wind, it’s different.

Just buy deeper and forget about those frightened people that say you will certainly die because of deeper wheel at front :slight_smile:

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One of the benefits of a deeper rear wheel is that you can (safely) run a deeper front wheel. Having a deeper front wheel (which as you noted as a better impact on aerodynamics) than rear can be problematic in crosswinds.

The logic if I recall is if the center of pressure of the bike profile is too far to the front of the bike (in front of the center of gravity, I think, but it’s been awhile since I’ve read this) then crosswinds will turn the front wheel instead of just displacing the whole bike sideways.

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Thanks @jakchylinski

You’re telling me what I want to hear! I would love to go 50/50 if I thought I could get away with it.

The deeper you can go on the rear wheel the faster you’ll be. Taken to the extreme, run a disk on the back.

As others on this thread have pointed out one of the main advantages of running a shallower rim depth on the front is that it vastly improves handling in a crosswind. It’s pretty amazing how much rim you can comfortably ride on the rear in a crosswind.

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Interesting stuff @Alaric83. Thanks for the input. :+1:

Good to know. I’m slowly gaining confidence in deeper rims here! Thank you.

I bought my first set of aero wheels last year. I went for 50mm because after looking at charts 38mm wheels didn’t seem that much more aero than a non-aero wheel.

At first, gusts of wind made me feel hesitant but now I’m 100% used to them. I now wonder why you’d want to ride anything smaller and I really wouldn’t mind trying out some Roval CLX64s or Knot 64 wheels (wider, deeper with fully aero optimized tires).

I had an interesting aero experience this weekend. I’m with two team mates. One is on an older Cervelo S5 (aero frame). The other is on a Giant TCR (aeroish frame). Neither have aero wheels. I’m on a Colnago C59 which has the aero properties of a brick but I have my 50mm wheels.

Both guys on aero frames got a head start on me. The TCR rider was doing the super tuck. I just got as low and aero as I could. I don’t do super tucks. I caught both of these guys halfway down the hill and I never pedaled at all and I blew by them at 50mph.

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Wheels make more of a difference than frame does (in $/watt saved, aero frames aren’t a great upgrade unless you’re either buying a bike anyway or have upgraded everything else already).

That said, weight matters a lot going downhill.

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Hi @AndyGajda its Kev Wemyss here. I would be interested in your thoughts on my original post if you wouldn’t mind casting your eyes over it. Much appreciated.

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Oh, Hi Kev!! I was wondering who might be from the Highlands here!!!

I’ve not heard of those wheels before, but they get really good reviews! And Sapim-CX Ray spokes are a good plan as you’ll be able to get them anywhere in the event of a break.

Personally, I wouldn’t bother with the shallow front, deeper rear. Given where you’ll do most of your riding, and you’re goals for the season, I’d go with the lighter option if I’m honest. You’ll notice a difference on the climbs. I’ve got a set of Roval CLX32’s as my go-to race wheel, and although they are shallow, I prefer them even on flatter terrain to my Zipp 303’s. The 303’s might be slightly faster into a headwind, but are slower on the climbs. Any race with elevation, I go for the CLX32’s.

I’ve also got the CLX64’s for my TT bike. They are a handful in the wind, especially gusty crosswinds.

So, in you’re position, I would personally go for the lightest option:-)

(Or you could go and speak to Kenny as he’ll give you some pearls of wisdom to let you make the best choice!! He actually talked me out of Di2 and made me realise that for amateur RR, rim brakes are still the better option. You won’t get a compatible disc wheel from neutral service in race yet!!)

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I have mixed 38/50mm wheels, mainly because I destroyed my rear on a pothole so I replaced it with something deeper. I have no issues, but I doubt I would have issues on a 50mm front either, and would probably be quicker.

I am planning to go to 44mm front 55mm rear at some point (30mm wide rim upgrade) as I just like how the mixed rim depth looks

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Firstly, i think slightly bigger on the back than the front looks cooler.

I wouldn’t go any bigger than 50 on the front. Bigger and you are limiting yourself to calm days.

I like the sound of 38 front and 50 rear.

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And I’m 80kg and have had a couple of deeply unpleasant experiences with a 50mm front! No problems at all on the flat, or on the relatively short and sheltered descents we normally get in the UK. But on the high mountains e.g. the Alps, when things are more exposed, the wind is gusting, and you’re descending for 20 minutes or more, there have been a handful of times I really wished I’d put on something shallower.

Think 50mm is fine the vast majority of the time. But given that the OP said he is doing the Etape, I would definitely err towards the shallower front wheel just in case it happens to be one of those windy days. I’m sure a deeper rear is no problem from a handling perspective but not sure there is enough aero benefit to justify it.

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Sure, but again. I am tiny, light - as you may expect mountains is my kingdom, on flats I just try to survive. I know there are situations when wind gusts cause problems but I have all of this tested many, many times. Seriously - when you can’t ride straight line you would experience the same with shallow wheels. You just blame the wheels :slight_smile: Riding shallow wheels you never think “it’s because my wheels” as they are already shallow ones. Those thoughts come up only riding deep sections.

But this is my opinion only, I don’t want to even pretend objectivity :slight_smile:

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I’m pretty sure it was the deep wheels in my case! Bought my first road bike in 1993, been up and down a lot of mountains since then. Was on various sets of shallow box rims until about 2008 when I bought some 30mm (seemed huge at the time!) wheels, then some 50mm ones in 2016. Never had an issue with the box or 30mm wheels, on the 50mm wheels I’ve had maybe 3 unpleasant descents due to wind. Not enough to make me regret the purchase at all, but enough that I do tend to check the weather forecast if I’m heading to big mountains, and take my old bike with shallower wheels if it looks windy.

Also possible it’s bike-related I guess, since the deeper wheels came with a new aero bike. Position is exactly the same on both my road bikes, but I guess the deeper cross-section on the frame and fork on the aero bike might also be having an impact as well as the wheels.

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If you’re getting whole new set why not get 50/50 but keep your existing shallow front? That way on calm days your as slippery as you can be but have a shallow spare for the windy rides.

It’s not going to be matched but it’ll cover more bases. I’ve got alloys 33mm and plan to do this with some 50mm wheels.

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I noticed the avatar before I noticed your name! :slight_smile: I knew you would come back with good advise to chew over. That’s reassuring that your preference is shallower rims for races with any elevation.

Thanks for taking the time out, I really appreciate it.

Your words are noted, thank you for your input.

Thank you for your opinion, each to their own and I appreciate where you are coming from.