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If you’re still running 23mm tyres on your road bike, it could be time you made the jump to 25s, or even wider

For many years 23mm wide tyres were the default choice for road bikes. Many racers used 21s or even narrower. In the last few years 25mm tyres have become the most popular option for both professional and amateur riders, and some riders have gone wider still. If you’ve not yet made the switch, it’s about time you did. Here’s why.

Comfort

Wide tyres can provide more comfort than narrow tyres, all other things being equal.

With a larger chamber of air between you and the road, a wider tyre allows you to drop the pressure without running the risk of a pinch flat (where the inner tube gets punctured as a result of being sandwiched between the wheel rim and the ground). The lower pressure increases the amount of cushioning you get from the road, improving your comfort.

That’s pretty straightforward, right? You’d expect a wide, soft tyre to be more comfortable than a narrow tyre that’s pumped up hard.

Check out road.cc's tyres review archive

Why is comfort important? Well, we all want to feel comfortable when we’re riding because life’s just better that way, but there’s also a performance aspect to feeling good on the bike. You can get more from your body when you’re comfortable than you can when you’re feeling battered and bruised. “Smoother is faster”, as Specialized is fond of saying.

Zipp Tangente Speed tyre

Zipp Tangente Speed tyre

We check out the bikes at a lot of top-level races and we reckon that about 75% of riders in last year’s Tour de France had switched to 25mm tyres, maybe even more. That’s for standard road stages, not going over the cobbles when riders go even wider.

Surely, though, the flip side is that wider tyres are slower? Well, no. It’s not as simple as that.

Rolling resistance

You’d like your tyres to roll as easily as possible but a certain amount of energy is lost through rolling resistance, which is the energy is takes to flex the tyre body where it touches the ground. Lots of factors determine rolling resistance, such as tyre width, profile, air pressure, material quality, and the thickness of the tyre casing and tread.

“Wider tyres roll faster,” says Dave Taylor, Marketing Manager at tyre brand Schwalbe. “The answer lies in tyre deflection. Each tyre is flattened a little under load. This creates a flat contact area.

“At the same tyre pressure, a wide and a narrow tyre have the same contact area. A wide tyre is flattened over its width whereas a narrow tyre has a slimmer but longer contact area.

Schwalbe tyre contact area  - 2

Schwalbe tyre contact area - 2

Contact area of a wide tyre © Schwalbe

“The flattened area can be considered as a counterweight to tyre rotation. Because of the longer flattened area of the narrow tyre, the wheel loses more of its roundness and produces more deformation during rotation. However, in the wide tyre, the radial length of the flattened area is shorter, making the tyre rounder and so it rolls better and therefore quicker.”

Schwalbe tyre contact area  - 1

Schwalbe tyre contact area - 1

Contact area of a narrow tyre © Schwalbe

As Dave Taylor says, that’s when the wide tyre and the narrow tyre are pumped up to the same pressure. In truth, though, you’re likely to run a lower pressure in a wider tyre, increasing the size of the contact area. That will increase the rolling resistance above the level it would otherwise be, but according to figures from another tyre brand, Continental, a 20mm tyre with 160psi, a 23mm tyre at 123psi, a 25mm tyre at 94psi and a 28mm tyre at 80psi all have the same rolling resistance.

“In practice, the energy saving is even greater than in theory as the elasticity of the tyres absorbs road shocks, which would otherwise be transferred to the rider and so saves energy,” says Dave Taylor.

Aerodynamics

As usual, it gets more complicated when it comes to aerodynamics. It’s obviously true that a narrow tyre has a smaller frontal area than a wide tyre, but it’s useful to think of the tyre and rim together rather than just the tyre in isolation.

Wheel rims have generally started to get wider over recent years, partly because of the trend towards wider tyres. Zipp’s 58mm-deep 404 Firecrest carbon tubular, for example, has a maximum width of 27.5mm.

“Our wider rims allow the use of wider tyres,” says Zipp. “Tyre choice depends on what factor you want to prioritise: aerodynamics, CRR (coefficient of rolling resistance), grip, comfort, traction....

“You can still use narrow tyres on Zipp rims if your primary objective is aerodynamics, but if you want the ride qualities that a wider tire provides, the Zipp Firecrest and Firestrike rims do an exceptional job of supporting those tyres in their intended design profile.”

Zipp 404 Firestrike tubular   - 4

Zipp 404 Firestrike tubular - 4

Reynolds, Bontrager, Shimano and countless other brands have moved towards wider rims too. The Reynolds 46 Aero, for instance, is 46mm deep and 26.2mm wide.

“The current trend toward creating wheels with wider rims stems from the trend toward increasing the diameter of tyres, particularly in competitive road racing,” says Paul Lew, Reynolds’ Director of Technology and Innovation. “Wider rims offer better mechanical support to large-diameter tyres and are needed to help separated airflow reattach to the rims.”

Tour Tech Tejay Van Garderen BMC TeamMachine-011

Tour Tech Tejay Van Garderen BMC TeamMachine-011

Run a 25mm tyre on many narrow rims and you get an ice cream effect: a big, bulging scoop of tyre sitting on top of a skinny cone of a rim. The mismatch between one element and the other doesn’t result in a high level of aerodynamic efficiency. However, wider rims have been designed specifically for use with wider tyres, the rims and tyres work together aerodynamically. Airflow that is separated by a wide tyre is able to reattach better to a wider rim than to a narrow rim, reducing drag.

Even if fitting a wide tyre on a narrow rim doesn't improve the aerodynamics, you might consider it a swap worth making for other reasons, such as extra comfort.

Check out Paul Lew’s short article: Is Wider Better?

Why not go super-wide?

If this is true, why stop at 25mm? Why don’t we use 35mm or 45mm tyres on a sporty road bike?

Well, for a start they won't fit in most road bikes; a few still struggle with 25mm tyres. Second,  a super-wide tyre wouldn’t work aerodynamically with existing wheel rims. And third, wider tyres would add to a wheel’s rotational weight and dull the acceleration.

For all these reasons, it seems that 25mm tyres have become the new 23. Or have they? Specialized has tacked on an extra millimetre and is making its super-quick Turbo S-Works and Turbo Cotton tyres in a 26mm width, and rolling resistance tests conducted on behalf of Velonews magazine found them to be the fastest-rolling tyres tested

The 28mm versions of the best-rolling tyres will be faster still, and over the next few years they'll fit more and more new bikes as manufacturers expand their ranges of bikes with disc brakes.

Riders whose bikes will take them report that the 28mm versions of the fastest tyres really are another step up in comfort. For many of us they might yet turn out to be the best option. 

Read more: Your guide to road cycling tyres + 13 of the best options
Read more: Check out the full road.cc tyre review archive

Mat has worked for loads of bike magazines over 20+ years, and been editor of 220 Triathlon and Cycling Plus. He's been road.cc technical editor for eight years, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a past winner of the Cycling Media Award for Specialist Online Writer.

34 comments

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KiwiMike [1303 posts] 1 year ago
2 likes

"And third, wider tyres would add greatly to a wheel’s rotational weight and dull the acceleration"

 

By how much, and by how much?

Casting about the internet, I'm finding lots of people saying they can tell the difference, and lots of articles saying losing 250-500g from a wheelset has an undetectable sub-0.5% impact on energy required to get up to speed.

Schwalbe's new Pro One tubeless adds 40g per tyre going from 23 to 28mm. So assuming an 80kg rider/bike package, that's added 1/1000th of the mass. Or 0.1%. If my maths is gooder.

Has anyone ever done a double-blind proper case-controlled study of whether people can actually tell the difference weight/accelleration-wise between sensible tyre sizes i.e. 23mm and 28 or these days 30mm?

Wider is more comfy/grippier, hands-down.

 

 

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Thelma Viaduct [57 posts] 1 year ago
0 likes

I've just gone from folding 28mm Continental Grandsport + tubes to 30mm Mavic Yksion Tubeless with stans tape and sealant and saved around 100g per wheel.

So basically got more comfort, no chance of pinch flats, more resistance to other punctures. Would be interested in seeing rolling resistance tests.

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700c [1139 posts] 1 year ago
1 like

If you're buying a whole new bike/ wheelset, then yes it makes sense to consider speccing wider rims and tyres designed for it. 

Simply sticking 25's/ 28's onto an older, narrow rim may well off-set any marginal improvements in rolling resistance by being both maginally less areodynamic and marginally heavier.

The comfort argument I get, but the idea that somebody would seek out a minute rolling resistance improvement but discount any resulting weight increase sounds like being selective with the science! 

 

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Al__S [1246 posts] 1 year ago
5 likes

I'm a tart that like tyres with coloured sidewalls- quite a fan of the Vittoria Rubino Pro. But the daft gits (applies to most of the manufacturers) seem to only do colours in 23mm

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Initialised [323 posts] 1 year ago
0 likes
Al__S wrote:

I'm a tart that like tyres with coloured sidewalls- quite a fan of the Vittoria Rubino Pro. But the daft gits (applies to most of the manufacturers) seem to only do colours in 23mm

That's why I stuck with 23mm for so long

Thelma Viaduct wrote:

I've just gone from folding 28mm Continental Grandsport + tubes to 30mm Mavic Yksion Tubeless with stans tape and sealant and saved around 100g per wheel. So basically got more comfort, no chance of pinch flats, more resistance to other punctures. Would be interested in seeing rolling resistance tests.

I've just gone from Mavic Yksion 30mm (tubed) to Specialized Roubaix Tubeless 23/25 and the difference in speed is amazing without much loss in comfort. This is on Mavic Allroad Rims (19mm internal). It's hard to explain, it feels as if the bike wants to go faster the whole time. I had a similar feeling changing from a 28mm beaded Espoir to an Espoir Elite 23mm on 14mm internal rims.

But... it's a feeling and an anecdote. What we need is science.

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BBB [456 posts] 1 year ago
2 likes

Comparing completely different tyres in context of tyre width debate obviously doesn't make any sense.  GP4000s in 23mm will be always faster then Gatorskin in any width.

Going wider isn't necessarily about riding a fraction of mph faster but at least just as fast with much more comfort, improved tyre lifespan, lower puncture risk (from foreign objects) due to reduced pressure, more cushioning for you wheels.

I'm still surprised how many people put 100 PSI in their tyres.

I wouldn't dream about riding on more than 60-70PSI. Pneumatic tyres were invented tho offer suspension not to emulate solid wheels...  3

As for the extra few extra grams being a problem... Really?...

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Smthers [1 post] 1 year ago
0 likes
Al__S wrote:

I'm a tart that like tyres with coloured sidewalls- quite a fan of the Vittoria Rubino Pro. But the daft gits (applies to most of the manufacturers) seem to only do colours in 23mm

Same here, but with Michelin Lithion 2's.

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ChetManley [40 posts] 1 year ago
1 like

25mm? 30-32mm is where it's at!

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issacforce [212 posts] 1 year ago
1 like

Can't fit 25mm tyres end of, and am happy with 23mm on other bikes that can fit 25mm

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Arceye [21 posts] 9 months ago
2 likes

I can fit 25mm and did once. 

My 17 mile commute to work increased by 2 minutes with 25mm tyres.

Granted they were different brands of tyre between the 23 and 25.

However it does prove to me that the blanket "25mm tyres are faster" statement is BS.

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Yorkshire wallet [1344 posts] 9 months ago
0 likes

Just built an aluminium winter commuter up with 35s running at 70psi and I can't feel a massive difference in comfort over carbon road bike on 23s. Maybe a slight pothole difference but nothing much else.

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Bungle73 [7 posts] 8 months ago
3 likes
Arceye wrote:

I can fit 25mm and did once. 

My 17 mile commute to work increased by 2 minutes with 25mm tyres.

Granted they were different brands of tyre between the 23 and 25.

However it does prove to me that the blanket "25mm tyres are faster" statement is BS.

Err how does that "prove" anything when you just admitted that they were completely different tyres?? That fatter tyres have less rolling reisistannc has been scientifically proven.

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Morat [263 posts] 8 months ago
1 like
Yorkshire wallet wrote:

Just built an aluminium winter commuter up with 35s running at 70psi and I can't feel a massive difference in comfort over carbon road bike on 23s. Maybe a slight pothole difference but nothing much else.

 

Try them at 45 PSI and report back!

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Arceye [21 posts] 3 months ago
0 likes

This entire article clearly shows there are no real advantages to a wider tyre except the possible comfort which negates all other advantages instantly. 

Point 1. Comfort

"Wide tyres can provide more comfort than narrow tyres, all other things being equal."

With a larger chamber of air between you and the road, a wider tyre allows you to drop the pressure.  MEANING ALL THINGS ARE NOT EQUAL !!

Point 2. Contact Patch

The contact patch on the wider tyre is shorter but wider when pressures are the same, however the pressures would not be the same which the artical clearly shows. In other words, No advantage here either.

Point 3. Aerodynamics

Wider tyres REQUIRE wider rims otherwise they are LESS aerodynamic, so without the rims they are a dissadvantage. 

 Extra point. 

Wider tyres squirm around on rims which are not wide enough which can be scary when cornering at high speed. 

 

The more truthfull statement would be "wider tyres can give more comfort"   and that is the end of the advantages.

All other possible advantages require specific circumstances which then undo the comfort gains. 

From a personal experiment I have used both 23 and 25mm tyres on the same rims/bike for my 17 mile commute, with 25mm tyres adding 2 minutes and costing me an extra 25Watts average.

Will I use 25mm tyres? sure I will, when I am doing long rides and comfort is more important than time.

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wellsprop [316 posts] 3 months ago
1 like
Arceye wrote:

From a personal experiment I have used both 23 and 25mm tyres on the same rims/bike for my 17 mile commute, with 25mm tyres adding 2 minutes and costing me an extra 25Watts average.

Will I use 25mm tyres? sure I will, when I am doing long rides and comfort is more important than time.

25W loss because of 2mm difference in tyre width, measured on a commute?

I assume you are measuring your power using a conventional crank based power meter? If this is the case, the "cost" of the 25 Watts has nothing to do with the tyres, as the power is measured at the crank, that simply means the average power at the cranks was reduced by 25W (hence the 2 minute increase).

If you rode at the same power in both tests with 23mm and 25mm tyres (in a controlled environment) before using some fancy equations to equate the difference in time to the difference in rolling resistance (just trying to derive the equation is blowing my mind) and came out with a value of 25W, then I'd love to know your equation as I'm working on reducing rolling resistance and aerodynamic forces on bikes as part of my engineering dissertation!

Unfortunately, your methodology of experimenting doesn't sound incredibly robust, so I doubt you could substantiate the 25W being entirely due to the tyre width and not other factors (traffic, variable performance etc).

https://roadcyclinguk.com/gear/using-wider-tyres-road-bike.html/3#Bj60tI...

I don't know why the link to the results in the above linked article isn't working - it had a graph showing the results and the 28mm came out on top.

The wider contact patch is also beneficial, it reduces the tyre deformation (thus reducing rolling resistance), whilst simultaneously making it less likely that your tyre will skid. (Pneumatic tyres don't follow the classical friction model - hence why wider tyres do give more grip, regardless of F=μ*R remaining constant).

Aerodynamics does play a massive role however, a wide tyre on a narrow rim will not only feel horrendous and squirm but it'll also be aerodynamically rubbish as the flow will separate over the bulbous tyre and won't attach to the rim - unlike wider tyres on wider rims.

I have no doubt that in a controlled environment with an extremely smooth surface (velodrome), super high pressure skinny tyres are the most efficient, however, in reality, it does seem that 25 and 28mm tyres are outperforming 23's (and smaller) due to their ability to absorb bumps (increasing efficiency of power transmission), grip better and having a lower rolling resistance.

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Arceye [21 posts] 3 months ago
0 likes
wellsprop wrote:

 

25W loss because of 2mm difference in tyre width, measured on a commute?

I assume you are measuring your power using a conventional crank based power meter? If this is the case, the "cost" of the 25 Watts has nothing to do with the tyres, as the power is measured at the crank, that simply means the average power at the cranks was reduced by 25W (hence the 2 minute increase).

25 Watts MORE average power at the crank but still 2 minutes slower. 

 

Marketing BS doesn't work on me, if my real life experience is different from a book written by the people who sell tyres/wheels or represent the people who sell tyres/wheels, I will always believe my real life. 

25mm tyres make me feel like I am towning an anchor around.

 

However, I do accept without question, wider tyres offer more comfort when at lower pressures and more comfort gives less fatigue, which in turn gives better rider performance for longer times.

After a long ass ride on 25mm tyres I feel less fatigued by comparison to 23mm tyres with the same average power output, but the journey will have taken longer.

 

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rnick [130 posts] 3 months ago
0 likes

I rather miss the days of finding ever narrower tyres, which were pumped up to impossibly high pressures, often with the help of a garage airline. At least they looked fast and felt fast.

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simonmb [491 posts] 3 months ago
1 like

I recall going out on a pair of Continental Supersonic 20mm at around 170psi. Only did it twice. Felt fast (was no faster)... and uncomfortable (was uncomfortable). Best kept to track use. Currently luxuriating on plush 25s and even thinking of going up to 28s. Comfort, rather than speed,  dear boy.

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Bahrd [14 posts] 3 months ago
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KiwiMike wrote:

Has anyone ever done a double-blind proper case-controlled study of whether people can actually tell the difference weight/accelleration-wise between sensible tyre sizes i.e. 23mm and 28 or these days 30mm?

Wider is more comfy/grippier, hands-down.

I think there are two things:

1. perceptible difference

2. measurable gain

The former is clearly subjective and - as such - a subject of countless discussions. But the latter - since it can be measured in a reproducible way - can have a merit and thus be of importance for pro riders.

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hawkinspeter [905 posts] 3 months ago
0 likes

Personally, I think the difference between tyre widths is probably less than losses from running tyres either too hard or too low for the road surface. Thicker tyres may well have less rolling resistance, but aerodynamics will make more difference at speed.

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fenix [703 posts] 3 months ago
0 likes
Yorkshire wallet wrote:

Just built an aluminium winter commuter up with 35s running at 70psi and I can't feel a massive difference in comfort over carbon road bike on 23s. Maybe a slight pothole difference but nothing much else.

Too many variables there. Just change the tyres and you'll feel the difference.

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fenix [703 posts] 3 months ago
0 likes
Arceye wrote:

I can fit 25mm and did once. 

My 17 mile commute to work increased by 2 minutes with 25mm tyres.

Granted they were different brands of tyre between the 23 and 25.

However it does prove to me that the blanket "25mm tyres are faster" statement is BS.

That does sound odd. Out of interest what tyres were they?

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BehindTheBikesheds [626 posts] 3 months ago
0 likes

Roll down tests are a simple/simplistic way to see differences so long as you wear the same kit and keep the same body position and there's no change in wind speed.

I still reckon the fastest tyres I've had were a pair of 23mm Maxxis Xenith Equipe legere's (the older version). Pure slicks that meant you could go around corners at ridiculous speeds in the dry and on a newly laid bypass surface felt like you were Tony Martin and a wind on your back.

Mind you they were fag paper thin, lock them up and you might as well bin them because you'd get a puncture sooner rather than later. I got maybe 500 miles out of mine on the rear but jesus they were fast.

My favourite all around tyre is still a 32mm specialized pro, really fast rolling, comfortable and superb puncture resistance, shame Spesh stopped making them (Have 4 left in my stash!), Giant P-SL2 tyre in a 28mm is up there as well.

currently have Veloflex Vlaandaren 27mm and 25mm Conti Compeition (r/f) on my racing bike. Good compromise of speed/comfort/PR and durability.

Getting tyre pressures right also has a big knock on affect.

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jterrier [115 posts] 3 months ago
4 likes

This is like science vs feel, basically. I put tubeless 30mm s-ones on my bike, run at 60r/55f. These replaced the old 23mm tubed schwalbes run at 100/100. The difference was massive, my confidence went through the roof, i got more comfy for longer, so i went faster. The science to some extent is irrelevant if the effect on the user is to make them feel more confident. Feel vs science.

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P3t3 [411 posts] 3 months ago
1 like
Arceye wrote:

This entire article clearly shows there are no real advantages to a wider tyre except the possible comfort which negates all other advantages instantly. 

On real road surfaces wide supple tyres at lower pressure are faster. The very processes that make it more comfortable are also what make it faster. It's more efficient to absorb the bumps into a low hysteresis tyre system than it is to lift the vehicle and absorb the resultant energy into the wobbly bits of the rider.

It's the supple part that is important, this isn't going to work for a heavy cased marathon tyre. The pseudo science about contact patch is a bit of a nonsense explanation, on a flat surface with the same absolute pressure the narrow tyre is going to bend more and so hysteresis losses are higher. In reality this effect has a very minor contribution to rolling losses once you add in a rough surface e.g chipseal.

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joeytwobastards [1 post] 3 months ago
1 like

I love this article, and articles like it, because 23mm tyres are now really cheap  1

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Rapha Nadal [574 posts] 3 months ago
0 likes

I've found that the combination of 23mm tyres on 17mm internal wheels are very fast. Faster than 25's on the same wheels from my experience.  100psi front & rear because I'm 93kg. 

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Coodsta [113 posts] 3 months ago
0 likes

 I've become a total convert to wider tyres over teh last few year , so much so that I've sold my road bikes and now just use a cross bike. Skinniest tyre Inow ride is a 32mm conti gator skin, but my usual is a 38mm. Now admittedly I'm a 45 year old who's hung up his racing wheels, but I've not noted a massive difference in my strava times and, I can  go play on the gravel roads in the New Forest.  I can't say I've noted a difference in weight etc, but  I could lose  at least 5kg before i need to worry about being a weigth weenie. 

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ChrisB200SX [496 posts] 3 months ago
0 likes

My standard road bike (carbon) commuter is in the shop for everything to be upgraded, so I commuted on my Planet X Stealth this week...

The FLO60 wheels with 23mm Conti 4000 S II tyres absorb just about everything, I was genuinely shocked at the difference. I had old 23mm Vittoria Zafiro on the front of the road bike and 23mm Conti SuperSport on the rear on Shimano RS500 rims.

Tyres are essentially the same width but the FLO rims are wider internally. I've discounted the frame, seatpost and ISM saddle so i'm currently assuming it's mostly the tyre and wheels that are making such a stark difference, it's night and day without even changing to a 25mm tyre!

Road bike will come back with carbon post, FLO30 rims and 23mm Conti 4000 S II tyres, so we'll see how that feels in comparison, should give me an idea of what is making the most difference to comfort. If it is more comfy I can see myself going for longer rides and probably regaining some KOMs.

I've got some 30mm deep Shimano RS31s and 25mm gatorskins to use during winter, will be interesting to see if they are also more comfy.

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check12 [124 posts] 3 months ago
0 likes

Just out of interest, if you don't mind, where did you get your flo30s from?

 

 

ChrisB200SX wrote:

My standard road bike (carbon) commuter is in the shop for everything to be upgraded, so I commuted on my Planet X Stealth this week...

The FLO60 wheels with 23mm Conti 4000 S II tyres absorb just about everything, I was genuinely shocked at the difference. I had old 23mm Vittoria Zafiro on the front of the road bike and 23mm Conti SuperSport on the rear on Shimano RS500 rims.

Tyres are essentially the same width but the FLO rims are wider internally. I've discounted the frame, seatpost and ISM saddle so i'm currently assuming it's mostly the tyre and wheels that are making such a stark difference, it's night and day without even changing to a 25mm tyre!

Road bike will come back with carbon post, FLO30 rims and 23mm Conti 4000 S II tyres, so we'll see how that feels in comparison, should give me an idea of what is making the most difference to comfort. If it is more comfy I can see myself going for longer rides and probably regaining some KOMs.

I've got some 30mm deep Shimano RS31s and 25mm gatorskins to use during winter, will be interesting to see if they are also more comfy.

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