Will deep rims make me any faster over a 33 mile route?

daniel_b

Unscientific research alert!

I flogged myself on the CR1 on Tuesday, going pretty much flat out (for me) - bike currently weighs around 7kg, a tad under maybe, but I have some Mavic Cosmic Carbon Pro wheels to fit at some point soon.

The route I covered I know pretty well, and is a distance of 33.7 miles, with 1300ft of climbing.
My average speed this time, and my best to date, was 18.5mph.

I appreciate these are not lab conditions, I will be feeling different when I come to attempt it, the temp will be different, as well as wind speed and direction, so this is just a bit of fun really.
These wheels will add 250\300g in weight, but the tyres I will fit (Conti 4 seasons I think) are meant to have less resistance in theory that the ones on the bike currently (Michelin Pro 4 Endurance).

I'm aiming to try my best again, but with the new wheels, so what do you reckon it will do for my average speed?

Hoping to fit the wheels in the next week or so, and carry the ride out by mid July, as time and family allow.
My fitness is unlikely to increase by more than a handful of watts between efforts.

Worst case, I look forward to enjoying the 'woop woop' noise that they are meant to generate as they rotate through the air 8)

mamil314

Isn't she supposed to be quite old now? My friend back in uni dorm had a 4 metre long poster of just her eyes, it was mesmerising. Also, it was quite a long time ago.

daniel_b

mamil314 wrote:

Isn't she supposed to be quite old now? My friend back in uni dorm had a 4 metre long poster of just her eyes, it was mesmerising. Also, it was quite a long time ago.

Quite is highly subjective, she's only 43, and looks exceedingly good for it.
Saw her last year at the union chapel, great gig.

sloppyschleckonds

Could you drop a spacer or 2 from under your stem? That'll probably help more

mfin

Daniel B wrote:

so this is just a bit of fun really.

It's not.

shirley_basso

Try better tyres

orraloon

I'm Torn about responding to this survey, might give it a miss though that could be a Big Mistake.

daniel_b

orraloon wrote:

I'm Torn about responding to this survey, might give it a miss though that could be a Big Mistake.

Liking your work sir, liking your work.

Yes I do have spacers I can drop, and plan to do so, and as already alluded to the tyres fitted are going to be allegedly ones with less rolling resistance.
Will be intrigued to see what difference there is if any. Appreciate there may well be a placebo effect, but I have power measurement on the bike, so should be able to discount that to some degree.
I spend a lot more time in the drops now too.

I'm very much counting down the days until I can hear the glorious noise they make.

shirley_basso

Still crap tyres. 4000s II should be for best.

webboo

Daniel B wrote:

mamil314 wrote:

Isn't she supposed to be quite old now? My friend back in uni dorm had a 4 metre long poster of just her eyes, it was mesmerising. Also, it was quite a long time ago.

Quite is highly subjective, she's only 43, and looks exceedingly good for it.
Saw her last year at the union chapel, great gig.

You clearly have injected someone’s crack rather than your EPO.

daniel_b

Shirley Basso wrote:

Still crap tyres. 4000s II should be for best.

Haha, my mistake, that is exactly what they are!
23 for the rear, and a 25 for the front. Not risking the rear stays on it.

And I have been nowhere near anyone's crack thankyou very much Webboo!

joenobody

Anecdotally I'd say that adding deep (ish - 45mm) rims to my bike, moving up from 27mm, has added about 0.8-1mph to my average speed over 20 miles. Looks to be an improvement also over 20 miles (30 is my longest ride so far), albeit a bit less. I'm short of comparative data points for rides over 20 miles though, so it's difficult to say for sure. Fitness wise I'd say I'm not as fit this year than last, having not really done any training (or even just riding) between October and May.

ben@31

If you like them, buy them. It's your money.

daniel_b

JoeNobody wrote:

Anecdotally I'd say that adding deep (ish - 45mm) rims to my bike, moving up from 27mm, has added about 0.8-1mph to my average speed over 20 miles. Looks to be an improvement also over 20 miles (30 is my longest ride so far), albeit a bit less. I'm short of comparative data points for rides over 20 miles though, so it's difficult to say for sure. Fitness wise I'd say I'm not as fit this year than last, having not really done any training (or even just riding) between October and May.

Hi Joe, blimey, that's quite a difference over 20/30miles, and you reckon you are still faster despite being less fit? That's mighty impressive if so. Is that purely based on feel, or power stats too?

ben@31 wrote:

If you like them, buy them. It's your money.

Misunderstanding Ben, I would have popped this on Road buying advice otherwise.
The wheels are already bought, just need to find the time to fit tyres, and change cassette.

This is just a bit of fun for me, to see what other people think or have experienced, and then I will report back in a week or two once I am able to repeat the ride with the deep wheels.

norvernrob

I’ve had allsorts of wheels ranging from 52mm to lightweight climbing wheels. None made me go noticeably faster or slower over any of my local loops. Wind, how rested I was and what time of day (I’m always faster in the evening than first thing in the morning) make the real differences.

cycleclinic

There areo gain from wheels is real. The difference in CDA is not huge but real. Even a 2% drop in CDA means a 2% drop in power required to overcome air resistance.

Rolling resistance test are junk though. How the tyre perform on real road can be different. On smoother tarmac and a 23mm tyre about 110 psi used to the lowest crr, higher due to bouncing increased crr. Since roads have become rougher though wider and lower pressure tyres are needed as the tipping has moved to lower psi.

One neglected area if marginal gain are the tyre rim combination. Take a 25 mm continue gp4000s we all on that gallons out to 28mm on a wider rim. That rim may only be 24mm wide. The air become turbulent fairly quickly as it passes over the balloon like tyre this not only increases drag but also decreases the stall angle making your wheels more if s handful on a windy day. So you have just lost some if the aero gains of your aero wheels. So the optimum seems to be and if you look at heds original patents for wide rims is a rim width/tyre width =1.05.

There is another effect too. Smooth tyre perform less well than textured tyres in aero tests. Essentially air becomes turbulent more quickly on a smooth tyres increasing drag and decreasing stall angle. This also should make your bike more of s handful on a windy day. Tyres with a fine thread pattern ( better I think if it goes to the bead) do perform better aerodynamically because a boundary layer of air "sticks" to the tyre surface and air moves over air far more easily than anything else.

If aero did not work then Adam dungelby would not have done 322 miles in the national 12hr TT. Aero gains are marginal but they add up. Position and clothing are important too.

Yes if done right wheel do make you quicker but with the right tyres to get the gain or the gain is smaller.

This is why aero testing the way it is often presented is junk.

There is also the way the air flowing past the wheel interacts with the fork.

veronese68

I reckon the new toy effect will be the greatest. I’m not talking about NI in that respect, even though 43 sounds young to me these days.

joenobody

Daniel B wrote:

Hi Joe, blimey, that's quite a difference over 20/30miles, and you reckon you are still faster despite being less fit? That's mighty impressive if so. Is that purely based on feel, or power stats too?

Based on average speed over the total ride (according to Strava, although it does say my "calculated" average power is up about 15W). From what I can tell it seems to be because I am now hitting, and holding, faster speeds on the flats. I'm still as crap as I've ever been up hills.

DavidJB

I think you'd get to about 26MPH average with those rims.

N0bodyOfTheGoat

IMO the question is wrong.

It should be, IMO... Will the new deeper rim wheels make me faster on the same route with the same average power and similar weather plus traffic conditions?

To which the answer will be, "it depends."

If you rode the route with the old wheels and tyres to an average power you could repeat with the new wheels and tyres without fatigue being a factor, in similar weather and traffic, they ought to be quicker (especially if you have very few junctions and traffic lights to deal with).

dannbodge

Average speed will be lower because sod's law means there will be a massive headwind from now on

mfin

Whatever the difference is in average speed, being less or more, it won't be down to the wheels or reflect the difference the wheels have made. It's complete bollōcks. This is the kind of thing people believe though even though there are way too many factors for it to be in the slightest bit proof of anything.

You could eliminate things a bit, ride the same route 100 times, and each time you come back, swap the wheels. Then get the average time of the 50 rides on one set vs the other.