Most of my wheels are old school and have a 13mm internal width. A few have the "wide" 15mm width. I once squeezed on a 28mm tire, on a rear wheel, for winter riding, on one of those 13mm rims. Don't forget that you need to know the E.R.D. when building wheels up.
As wide as possible! Gravel: 28mm 700c (Nukeproof Neutron V2 - it's a non-boost MTB wheelet) and 26mm 650b (Prime Orra). Road: 25mm 700c (Zipp Firecrest 303) and 23mm 700c original set of the gravel bike.
I run 700x30 tires on 25mm ID rims on my road bike. I’d love to see this test repeated for road surfaces as compared to gravel. Great video either way Si.
Perhaps a better experiment would keep constants constant like using aluminium wheels for both widths and using black or gumwall tires for both wheels since wheel composition and even sidewall composition can make a big difference in feel.
Most modern “gumwall” tires are the same as the black. The sidewall rubber is just brown instead of black. Panaracer is probably the only manufacturer of a tire that would be close to a traditional gumwall.
Stephan, you are half of the reason I even watch this channel. I don't know what you guys do to record such crisp sound both indoors and outdoors, but other folks in RU-vid could learn a lot (including GCN en Español). The camerawork is also *chef's kiss*.
I have a set of Zipp 303 firecrest(25mm internal) on my Aethos with 28mm skins(@50psi) except this year I'm moving to 30mm tyres and dropping the TP to around 48psi(maybe lower) front and back.
Love my hookless wheels. I'll probably never buy a hooked wheel ever again. My guess is that they just had the pressure too high. Even at 90kg, no issues. That said, we saw way more failed tubulars than tubeless but it wasn't news because it was just a thing that happened from time to time.
Guys, the rims should have been identical materials, spokes gauge, spoke number, spoke tension, nipples, and rim cross section. To start Alloy is more compliant than carbon. You introduced a ridiculous amount of a variables and did not account for any of it. Carbon wheels micro bounce/chatter over bumps and this decrease grip. Alloy flex more and increase grip, generally
I know it takes lots of energy to produce videos. It's a fun video to watch, mission accomplished, thank you. Now back to the topic. The tire/wheel/rim system has the most profound effect on perceived and actual ride quality. This is more so than any other variable, (frame geometry, frame materials, components etc.) I'd would love to see some single test bike and rider used with appropriate sensors, to test an array rims and tires. The sensors would measure transmitted vibration to the frame. The amount of vibration "may" be correlated to efficiency and rider energy conservation (fatigue). Lowering these "may" preserve watts and mph/kph. Just a thought.
My old touring rims on my road bike are 19s, and pinched the 28mm Contis I tried to run for greater comfort (@ 10 years ago) enough the front tire would scrape the underside of the fork crown under rebound. Now, I was running 100 psi (I run about 80-85 now) so that likely attenuated the bulbousness caused by narrow rim and larger tire. At least, that's how I looked at it at the time, as I dropped back to 25mm tires. When I bought new wheels for my gravel bike two years ago, I went from 23mm OEM's to 25s, and it seemed to spread the tread a small amount and create a better ride, on and off road. I'm too cheap to replace the road wheels with wider rims until these finally wear out (and I mostly ride my gravel bike anyway), but when I do I'll go with wider inside width rims and see if the 28mm tires don't hit the crown anymore.
Highly unscientific of comparing apples with oranges as usual, but very well put together and entertaining as always! As a roadie who's bought a lot of Chinese carbon rims, I buy wider and wider, which means I can run wider tyres (currently 30C front and 32C rear), with a flush interface, which means I have aero wheels (I do routinely find myself going fast), and now I laugh even at gravel sections or crappy asphalt, when on 25C I was very wary of getting punctures. 32C rear is a chonky boi. And comfy. My butt likes.
Si believe comments section will push back on your comparison mate. Wheel design difference would for your particular test would have as much to do with 'feel' difference than width. Likely not even the same thread count tires used for both sets of wheels. Reality is, for any meaningful dive into a give bike spec, other factors have be held constant or there is a biased result. None-the-less, you put a lot of effort into this video and thank you for that as you did touch upon many dynamic differences. Takeaway for the amateur rider is...buy good cheap aluminum narrow rims to keep weight down as mentioned for gravel or mtb and have at it. If you are an elite amateur or pro, of course chase that last watt. Only thing wider carbon rims will do is make your wallet lighter as stronger riders pass you on the trail.
Simon! I'm so curious to hear of your experience with riding a bike wearing your vision deprivation system !! I'm half blind (one eye doesn't work) and the other one has a significant blind spot in the lower half. What that means is that I see about what you saw with your visor in place! (minus the right visual field) My question, did you find yourself hitting unsuspecting holes, bumps, sticks/roots etc? Was it alarming or frightening? I know not the point of your video (which was super neat and informative), but I so rarely get to compare notes with a similarly impacted athlete. XOXO, I have loved watching the channel grow over the last decade. You people are such great personalities and ambassadors.
It can make a difference in my experience but how noticeable depends on the difference between the rim and tire. I rode a 28c road tire on a 28mm internal mountain rim. It was super aero but it rode very harshly. I think because it essentially had no sidewall. In my experience wider is better but most wheel and tire combinations have a kind of an efficiency zone whereas long as you’re close enough it’s works well. It’s not critical. Just don’t go to extremes.
(as you pointed out at the end of the video ) You're supposed to use the silica calculator and with the wider rim lower the air pressure with the wider rim to be a fair comparison.
I always love watching Si do tests but come on. Testing to to tell the difference rim width makes....... But using wheelsets of different materials and a significant weight difference? Dr Bridgewood can explain scientific control. 😊
Everything seems to be convincing despite one thing. If you compare carbon rims with 21 mm to the same carbon model which has 25 mm you will notice that increase of rotated mass is about 100 or more grams. So you need to consider that bike becomes heavier and this is one of the problems of modern bikes that they are more and more heavy... To be honest I want 100 or even 200 grams lighter wheels than 0,5 W of lower rolling resistance 😉
Every specific rim width for every specific tyre width, plus/minus a mm, mm and a half if you're liberate. Simple as this. Unless bike tyre manufacturers adopt automotive principles of tyres with different width/profile ratios.
Certainly in the motorcycle, and for that matter automotive world, tire and rim width are usually specified together. You wouldn't put a 180 width tire on a 3" wide rim - it would completely distort the intended tire shape. So maybe bicycle tires should specify the intended rim width.
Did I miss it or was there a surprising omission of any mention of tire hysteresis? More importantly why faff about with the visor, why not just black out the bottom six inches of Si's riding glasses?
I would like to see them do this on just the front wheel. It would be fast and cheap to do, and tell us about steering dynamics without confounding factors.
Interesting, I have a question. Why did they think back in 1992 (when I was a proper cyclist and member of the cycling touring club UK) that thinner, the better - 23 no problem”
But was the speed difference down to the lighter carbon wheels vs the heavier aluminum wheels? Or was it down to the rim width? We can't say because you changed too many parameters in your test.
Equal psi in different rim widths is a silly test. At your weight, you should try 22psi in the 25mm rims. Then if you are good at deweighting the bike (think CX) you could ride them at 20psi. The wider rims at the right psi are night and day different when you optimise the psi...
The importance of width was made very clear on my MTB. I used to run a different rear wheel (a crap Jalco rim on a crappier shitmano hub) to my glorious Halo Tornado laced around a Hope Pro 4. The Jalco was 23mm, the Halo is 33mm. At that time I was running a matching pair of Continental Der Kaiser Apex tyres, 559-61mm the rear was lightbulbed to hell, the front was perfect. I since upgraded to a set of Brand-X trail wheels (tubeless and everything). 28mm with a 60mm up front and 57mm out back. Both tyres have the perfect profile and are fast as hell. Grip, cornering performance and comfort are all improved by the right rim.
Like he isn’t going to see the tire… come on.. we all know he will get a view at some point from the bumps and naturally looming down for clearance.. that visor isn’t going to do anything lol
@simonrichardson5259 i find that hard to believe you didn't accidnetly glance down even once lol. We still believe you.. but the tempation or habit i feel like would get you.
I was going to make fun of this video because of the groundbreaking information 😜 but since Sy makes videos fun to watch even if the information is not , well groundbreaking 🤣. Very entertaining 👍
I run 25mm tyres on my road bike (widest ones that will fit under the mudguards). If I had 23mm internal rims, wouldn’t the tyres just fall off? Anyway my internal rims are 15mm apparently (Mavic Open Pro rims)
do remember when mavic rated the 22mm external width x517 mountain bike rim to 2.5inch tyres. times have changed. but i dont' mind 20mm internal up to 29x2.0 xc tyres
Anyone knows? Reserve 40 44 wheels says max 40mm tire for theirs 25 internal rims. If you want to go wider 40-50mm tire you need to buy 27mm internal gravel rims. Any idea why they don’t want you to write 45-50 mm tire on 25mm rim ? Makes no sense to me.
When is the road only version of this video coming out? And what about mismatched tire width? Should two different width wheels be used? I have Elite Wheels 45D DRIVE that have 21mm internal width. On the rear there is 32mm Conti GP 5000 and on the front 25mm Conti GP 5000. The winter here is brutal at 6134 feet so I have not had a chance to ride with them as yet.
Most of SI tests are badly conducted. How about you choose the same material for both sets and maybe try to produce the same power, speed or heart rate.
I think a new tire, bike or even jersey makes you faster the first couple of rides. Probably the risk taking inspirational effect. After a while it wears off and you want something new again
Thanks Si for risking life and limbs (limited vision) on this test. I ride on road with a wider rims, and the extra comfort (lower tyre pressure) is appreciated with what feels like no sacrifice in speed.
I wan to get some really wide gravel tires but I'm finding the selection is VERY limited. Most of what manufacturers are calling gravel wheels seem to me to only be sized right for about 30mm tires. Of course I want some for 40mm tires.
Zipp 404 58mm depth 23mm ID on one bike. The others are probably 20 ID ballooned and 23 ID mm. I'm changing the 20 out soon..fast but super squirrely...it's going to get the ENVE Ses 70 mm depth 23mm ID. But I don't ride gravel yet.
My wheelset have a 17mm internal rim width,but they are very strong being Mavic Crossmax SLR's,hit a pothole at 40km/h and the rear only dented slightly which was later removed with some careful tinkering.😬
Just went from 30 to 35 internal. NIGHT and DAY difference. Smoother. But here is the thing. When going over curbs and rocks the rear of my eMTB always shimmied a bit side to side. Now I have way more control and comfort. Why oh why did Specialized do this to me? So much so I can ride no hands now. Narrow wheels are just STUPID on a mountain bike. But this study was stupid comparing apples and strawberries. You should have made them both same material. Sheesh! Has anyone done science? The watt saving would likely offset the increased mass.
I couldn't help but notice the carbon gravel wheel had a big chunk gouged out of it. Seems like a questionable wheel material for an application where rim hits are likely?
I just happened to have a 30mm rim and a 40mm tyre laying around... Fitting was not so nice, but the result is not square at all. Measures 42mm wide. Definetely something to recommend with 45...50mm tyres
I have two sets of wheels: Stans and Reynolds. They are different materials. There is a 2mm internal rim width difference. I ride 28mm on the narrower rims and between 38mm to 43mm tires on the wider. The difference in feel is dramatic. However, the wider tires do have a noticeable increase in drag.
