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-   -   Tire Width Myths (https://www.bikeforums.net/showthread.php?t=1227771)

bigevil 04-08-21 08:41 AM

Tire Width Myths
 
https://www.renehersecycles.com/bq-tire-test-results/

Pretty interesting read.

This comes after a long (and friendly) debate with my local Trek store manager. After throwing Aeolus Pro 37s on my Checkpoint SL6 for better road days he was pretty passionate about the 44mm extralight supple tires.

I've been back/forth thinking I was silly for this setup when the general forums and friends vibe is "put 28mms on your road bike" But I found the article quite convincing. I did buy some Conti GT5000s in 32 and 28 to compare but while they're being shipped figured I'd turn it over to the community for thoughts since much of it is above my head.

Wildwood 04-08-21 08:57 AM

The current belief that fat tires at low pressure have 'almost' the same rolling resistance as skinnier hard tires is 100%BS.
Yan is selling superb fat tires at high prices - you need alternative facts to do that with a straight face when talking rolling resistance.

Gravel riding = fat tires help with control on descents or if the gravel is thick, soft surface, etc
Off road = fat and soft absorb bumps which IS a big advantage.
That's why my mtn bike is a rigid, cross country style.

Iride01 04-08-21 09:01 AM

You should try tires out for yourself and see what they do for you. Run them at different PSI's and note your perceived effort and your actual ride metrics over the course of your experience with those tires. If that is till they wear out, that's fine. When you put another tire on there start all over with your perceptions, ride metrics and eventually you won't have to ask others what you should do.

Cyclist0108 04-08-21 09:03 AM

The "alternative facts" in this case are backed up by data that contradict the functional equivalent of fakebook rumors and old wives' tales.

There are some very worthwile threads here on Compass/Rene Herse tires.

I am pleasantly surprised to hear that a Trek dealer would advocate for them.

Koyote 04-08-21 09:04 AM


Originally Posted by bigevil (Post 22005801)
https://www.renehersecycles.com/bq-tire-test-results/

Pretty interesting read.

This comes after a long (and friendly) debate with my local Trek store manager. After throwing Aeolus Pro 37s on my Checkpoint SL6 for better road days he was pretty passionate about the 44mm extralight supple tires.

I've been back/forth thinking I'm a fool for this setup, or maybe I was upsold yada so I did buy some Conti GT5000s in 32 and 28 to eventually compare but in the meantime he sent me this pretty convincing argument.

Figured I'd turn it over to the community for thoughts since much of it is above my head.

I'm curious: do you race or participate in a group ride in which you have difficulty maintaining the pace?

unterhausen 04-08-21 09:12 AM

Many of the guys I can't keep up with on long distance rides use RH tires. I don't think it's the tires making them faster, but it could be. Jan is also quite fast.

I ride with someone that uses 44mm tires. He's about my speed or maybe he's a little slower on average . The thing I noticed was on rough chip seal it's hard for me to keep up with him. So it really depends on what you are riding, but I expect a fit rider on wide tires could stay up with a group without issue.

bigevil 04-08-21 09:16 AM


Originally Posted by Iride01 (Post 22005834)
You should try tires out for yourself and see what they do for you. Run them at different PSI's and note your perceived effort and your actual ride metrics over the course of your experience with those tires. If that is till they wear out, that's fine. When you put another tire on there start all over with your perceptions, ride metrics and eventually you won't have to ask others what you should do.

​​​​​​That's a great idea, I mean may as well try em for a month at different PSIs on all my typical rides and see how they fare. That said I did my usual ride yesterday and felt not only was the general resistance harder, but I wasn't super stoked on my descent freewheeling. Maybe much of it in my head, too early to tell. But this is after a pretty nice massive wheel upgrade so I perhaps was expecting more.


Originally Posted by Koyote (Post 22005844)
I'm curious: do you race or participate in a group ride in which you have difficulty maintaining the pace?

Is this one of those "you're fitness isn't good enough to tell the difference" arguments? Bottom line no my fitness and skills likely aren't good enough. I'm a newcomer to the sport but I do ride 3x week building speed/FTP over past few months (not to mention at 124lbs small changes definitely make a big difference). That said I'm more curious about the article and its points more even than my personal experience.


Originally Posted by wgscott (Post 22005840)
I am pleasantly surprised to hear that a Trek dealer would advocate for them.

Me too! I really like this dude personally and trust him, I don't think I was being upsold at all, he was just passionate that I'd enjoy them so much more enjoyable over 28s or 32s. He even offered to let me return them if I still hate them though it's typically against policy. That said he's a avid MTB dude so I know he's a fan of wide! Much of his argument hinged on that my Checkpoint is truly meant to run 40mm+ tires for optimal handling because of the design of the bike which seems reasonable.

scottfsmith 04-08-21 09:22 AM

Thanks for posting this article. These are closer to the kind of tests that should be done, not the mostly useless indoor drum rolling resistance tests.

What I would like to see though is an independent study with similar tests, I don't trust any tire company testing their own tires against the competition.

Wildwood 04-08-21 09:24 AM

Just read your referenced post. At 123 lbs rider weight you really don't have to run much pressure in the 1st place.
You would greatly benefit with any tire that has supple sidewalls. 320tpi casings.

Iride01 04-08-21 09:29 AM

The way you ride your bike, hard and fast, leisurely or somewhere in between. Your terrain, rough or smooth road, your own perception of ride comfort and many other things will make tire sizing a variable for all. That's why we argue about it so much.

If there was a perfect tire width that was appropriate for everyone,. Then we all would be riding that one perfect tire.

Be a pain in the butt having to take it off and share it with the next person though <grin>

kingston 04-08-21 09:30 AM

I have been using compass/RH tires for a long time, I'd guess 8 or 9 seasons maybe, If you're going with a fat tire, they are hands down the best. I have bikes with a lot of different tire widths and have pretty much settled on 25mm for road rides 200k and under, 28mm for longer than that, maybe 32 if there's a little gravel thrown in, 38 if there's a lot of gravel, and >50 if its all off-road. I've ridden a lot of road miles on wide tires and prefer 25-28 almost all the time, and at that width there are lots of less expensive/almost as good-just as good alternatives to RH tires. I think 44mm RH-EL's are a fine choice for a checkpoint, but it wouldn't be my first choice for a road bike

Koyote 04-08-21 09:31 AM


Originally Posted by Koyote (Post 22005844)
I'm curious: do you race or participate in a group ride in which you have difficulty maintaining the pace?


Originally Posted by bigevil (Post 22005869)
​​​​​​T
Is this one of those "you're fitness isn't good enough to tell the difference" arguments? Bottom line no my fitness and skills likely aren't good enough. I'm a newcomer to the sport but I do ride 3x week building speed/FTP over past few months (not to mention at 124lbs small changes definitely make a big difference). That said I'm more curious about the article and its points more even than my personal experience.
.

No, not at all.

If you're not racing or struggling to keep up with faster riders, maybe just ride the fatter tires because they're more comfortable. Because they are definitively more comfortable.

wphamilton 04-08-21 09:37 AM

I clued into this around 10 or 12 years ago. While it was absolutely true that my wider tires were slower, at any pressure, it was because I'd buy the most inexpensive durable wide tires that I could find. By wide I mean 32's. Even when I wanted more supple 32's they couldn't be found, unless you were willing to pay 5-10 times the price for them.

I came to realize that if width and pressure make a difference - and I still don't doubt that they do- it's much less difference than the makeup up tire makes.

stevel610 04-08-21 09:48 AM

I am a fan of wider tires- don't ride less than 32's. As has been stated I find higher quality rides nicer. Though I think width and the higher weight do affect efficiency.

If you sign up for BicycleRollingResistance.com professional service you can change the rates to match your weight and speed. GP5000's go from 10 watts to 24 watts for me. I think this is nice to know though having a consistant method provides a better tire to tire comparison.

cbrstar 04-08-21 09:56 AM

Because I BMX maybe I have a different perspective. A big change in the world of BMX was tires going from 20 x 1.75 to 20 x 2.5. If I have a low amount of tire pressure lets say 40 psi then the smaller tire feels much faster. I could be wrong but I believe it is because the larger tire has a lot more flex/deformation because the volume of air pressure is much lower. The small tire is at 80-90% air capacity where as the bigger is a little less then 40%. This allows the bigger tire to make more contact with the road. But if I take the bigger tire and fill it up to 100 psi which takes the flex away and the tire is making less contact the rolling resistance is going to decrease and feel the same as the small tire.

With cars it's well known that lighter wheels = better performance. Some call it "un-sprung wheel weight". The bigger tire is going to have more rubber and more air volume so it's going to be a tiny bit heavier. But again other things are going to effect this like rim weight. Or the bigger tire being made from lighter material then a smaller tire. Also if the PSI matches the riders weight, as I am a bit heavier and need that extra PSI to not flatten out the tire. I think some people would notice the difference in wheel weight and others won't.

Cyclist0108 04-08-21 09:58 AM


Originally Posted by scottfsmith (Post 22005887)
I don't trust any tire company testing their own tires against the competition.

They aren't a tire company. They are a boutique vendor. The tire company that makes the tires is Panaracer. The Rene Herse people come up with the tire specs and test the prototypes and final products. They do have a stake in the outcome, and they do publish their results in their in-house publication (Bicycle Quarterly). But Jan is also a PhD-level scientist, and the results they publish have been corroborated by completely independent testing. (Bicycle Tire Rolling Resistance, for example, comes to mind.)

70sSanO 04-08-21 10:01 AM

If I recall the premise is that real life roads are not the perfectly smooth surface of a drum and the width and pressure maintains contact and rides more smoothly than a harsher narrower and higher pressure tire that bounce off the bumps.

Except for those competing, tires are usually a compromise for everyone else. Comfort, handling, durability, etc. all factor in since most of us don’t replace them monthly to maximize performance.

The bottom line, regardless of which side of the forever ongoing argument you are on, is to ride what you want. There are also psychological advantages to riding a tire you really like. I’m sure that on descents, improved body position would more than offset for perceived speed differences, but that doesn’t really matter.

The only problem with these threads are the passion in which some people feel a need to convince others that their position is correct. The problem with that is no one really cares who thinks what.

John

tyrion 04-08-21 10:29 AM

The BQ claims/results hardly surprise me - fat tires don't have a rolling resistance penalty, aero isn't very significant under 20 mph, and weight is weight (the article basically sidestepped weight). Seems to agree with most of the recent "real world testing" that's come out.

The most surprising thing was that the pedestrian $54 650x47 WTB Horizon was only 1.07 kph slower than the $84 RH 700x28 extralight with latex tubes at 400 watts - this is at 38 kph+ where I thought the fat tire would have more aero impact.

woodcraft 04-08-21 10:30 AM

In all tests shown in the article, the 28mm tires (the narrowest tested) are faster than wider ones.

dmanthree 04-08-21 10:42 AM

This discussion, wide vs narrow vs high pressure vs low pressure or any combination of them will never end. Way, way too many variables to arrive at a definite conclusion for all riders.

I'll stick with my trial and error method that always works, but always pay attention to any real quantitative analysis that can shed some light on new tires, methods, etc.

bigevil 04-08-21 10:44 AM


Originally Posted by Koyote (Post 22005914)
No, not at all.
If you're not racing or struggling to keep up with faster riders, maybe just ride the fatter tires because they're more comfortable. Because they are definitively more comfortable.

fwiw I'm def potentially not even experienced enough to know the real difference of any of these yet. But I did just spend a small fortune on the wheels and just want to make sure the tires I throw on are optimal. Especially as I'm set to start training with a coach and digging into longer road rides.

Pratt 04-08-21 10:45 AM

Not that will in any way settle this debate, in fact, probably the reverse, but you can find out if more or less pressure is faster in your tires by "brushing" with a friend.
Start out coasting eat the same speed, next to each other on a nice down hill. Then repeat with more or less pressure in your tires, and no change to your friend's. Similarly, keep the weights, positions, etc. unchanged from trial to trial. You should be able to see the effect easily. You can call sprinting back up the hill for another run "intervals."

tyrion 04-08-21 10:58 AM


Originally Posted by woodcraft (Post 22006040)
In all tests shown in the article, the 28mm tires (the narrowest tested) are faster than wider ones.

Testing was done "on a very smooth road". On rough roads the fatter, lower pressure tires would have an advantage.

icemilkcoffee 04-08-21 11:14 AM

Not that again. That 'debunking' has already been debunked:
https://www.bicyclerollingresistance...000-comparison

They tested the same GP5000 tire in 23,25,28, and 32mm against their rolling road drum, and found that the wider width tire only gives you better rolling resistance when pumped up to the same pressure as the narrow tire. Nobody does that in real life. Because that wide tire, pumped to the same pressure as the narrow tire, will actually be stiffer than the narrow tire! If you pump each tire to the manufacturers' recommend 15% drop (ie. the height of the tire is squished in 15% when you get on the bike), they are roughly the same, with a small edge going to the narrower tire.

Conclusion: used as intended (ie. wider tire gets lower pressure), there is no benefit with the wide tire. Once you take into account aero and weight, the wider tire is going to be the loser.

In the end, the simplest rule of thumb is this: Light rider= narrow tire. Heavy rider= wide tire.

Sy Reene 04-08-21 11:32 AM

Strange 'real world' testing IMO as regards tire pressure effects. They tested using knobbies on very smooth roads to draw conclusions?


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