30mm tires for 'performance' oriented road riding

I am competitive in P12 races on 28mm tires mounted to 23mm internal width rims. They are 31.5mm WAM and I typically run them around 62psi.

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Even with Chung’s method, you have to be pretty meticulous how you do the runs. You have to use the same wheel and bike, meaning remounting the tires which is a pain, and you need to do it on a day with the least wind possible, and an appropriate venue (car traffic in particular is going to be a problem). The smaller the effect, the more meticulous with data collection you have to be, and this is supposed to be on the order of a couple of watts at 35 km/hr.

When I have a nice day on the weekend where I can ride during the day as opposed to going out to ride or run at night during the weekdays, I just don’t have the drive to go to a suitable course with my van, bike and tools and do aero testing instead of riding my bike with my mates.

My solution is multiple bikes with different tire sizes, but I will be on the 25s when chasing speed. Need all the help I can get.

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Absolutely. Same bike, same clothing, same riding position.

But what’s the “fun” about science work without meticulousness? :wink:

I happen to have one of the starting / end points of a suitable course (~ 20 minutes lap time) less than 3 minutes of riding from my front door. I don’t need to touch the brakes on that course, not even at the turn-around point although it involves some climbing / descending. I found that it’s best to do those runs at night. Not only is the traffic even less of a problem, on most days that’s also the time of day when the wind stops or at least becomes a constant breeze without any gusts.

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Specialized has the S-Works Turbo RapidAir in 700 x 30. I have those installed tubeless on some Roval Terra CLs (gravel wheels) and have put at least 3,000km on them. Mostly training, but a little road racing. Never had a flat or any other issue with them. If I wanted a fast 30mm tire I’d be happy to buy them again.

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One of my favorite road setups is still a lightweight 28 mm (printed width) tubeless tire on an Enve 4.5 AR. That rim has a 25 mm internal width, and the inflated tire width ends up matching almost exactly with the 30.5 mm external width.

Pretty light, still very aero, great handling, fantastic grip. Couldn’t ask for more. Everything else seems small now.

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I’ve really enjoyed the set of 32mm GP5000 (tubed) tyres I’ve been using. I’m probably 4-5k km in and I can only remember one puncture, but most of those km were out of town (less glass, etc). There is a “suspension losses” reduction on the crumbling chip-seal roads here, but for me the real benefit is comfort and confidence. Riding on hot mix then I’m sure they’re slightly slower than 25s at 100psi, but I don’t have much of that near me (Adelaide hills).

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Another vote for GP5K TR in 28mm, my set weighed 275g each, mounted on 23mm internal rims they come up at 30.5mm. I’m using Bontrager RSL51 so the tyre width matches the rim width very well.
I’ve not noticed a lack of grip cornering but as the weather has started to turn here and roads are wet I do get some wheel spin on steep climbs on wet roads. On Vittoria Corsa’s I don’t.

Vittoria just know what they’re doing when it comes to grip. I’ve been using the N.EXT’s and Open Pave’s recently and there’s plenty of grip even when riding on a layer of wet leaves. Conti tyres in particular are just nowhere near the same levels of wet grip.

The testing suggests that they don’t roll quite as well as the competition and also Corsa’s are terrible for punctures but when it comes to grip they’re great.

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I agree, unlike a couple of watts of rolling resistance the grip is actually perceptible in the real world. The Open paves were my go-to in winter for years - great tyres. I’m giving the NEXT ago this winter, the grip is great, but already had my first puncture on them though it did seal pretty quickly so will see how they go.

If my bike’s specified max tire size is 30mm, but I see a decent amount of space left over, am I okay trying out 32mm? The wheel’s internal width is 19mm. I’d be inclined to do this during the winter slippery season, but this is probably when the most crap would stick to the tires and potentially hit the frame.

Am I the only one to notice a huge worsening of the “handling” in cornering with increase width of tires ?
I have 2 bikes with GP5000 : 1 with 25mm tube type (73/78psi, 17 internal width rim), 1 with 32mm tubeless (40/44psi, 22 internal width Rim). Cornering with the 32mm feels very weird and difficult.
Is the pressure too low ? But If I increase the pressure I do lose the confort profit of large tires.
Kind to read your thoughts and advice about that.
(NB : possible bias but can’t explain everything : geometry isn’t strictly identical : Cannondale supersix evo vs SuperX)

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The bike geometry is likely having an effect - the SuperX has a slightly higher bottom bracket and slacker headtube angle, so I wouldn’t expect it to corner quite as well as the SuperSix. You’d really need to try both tires on the same bike.

You could try increasing the pressure on the 32 mm tires as an experiment to see if the handling was affected.

Some manufacturers are very conservative with tire clearance claims. Canyon claimed that my Endurace could only fit 30 mm tires, but the supplied tires measured 32 mm and there was plenty of room. I aim for a minimum of 4 to 5 mm clearance at all points, but I ride in a dry area and can get away with less.

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I don’t know how heavy you are but 40psi does sound low for 32mm tyres - I run 45mm gravel tyres are 35psi. I’m 80kg and I run my 30mm tyres at 60psi.
And yes your bike geo will very likely be affecting this as well.

The tyre pressure sounds too low to me unless you’re very light.

However, it could also be due to using a CX bike on the road, I’ve never been a fan of it myself as it feels quite skittish and unsteady due to the high BB.

I’m gonna’ run some Pirelli P Zero Race 30mm clinchers with latex tubes. as I recall, stated weight figures on those tires were lighter than comparable Continental, Shwalbe, Vittoria, etc.

Sorry, a bit late for this response maybe, but…

Continental GP5000 have lower rolling resistance than the Pirellis, and in 28mm will like plump up a to 29/30mm on your rims, so will probably be more aero than the 30mm Pirellis on you wheels (which may well end up at 32mm or wider once fitted).

Ignore the relatively small weight difference - aero and rolling resistance are far more important.

Am I the only one to notice a huge worsening of the “handling” in cornering with increase width of tires ?

As you increase tyre width, you also increase tyre height, which lifts the bike and has the effect of increasing fork trail, which results in the bikes steering/handling response slowing down.

This will be the same for every bike, but the effect will be more noticiable on some bike more than others as head angle, wheelbase and fork offset will all feed into how noticable the change is.

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even with 30’s on my wheels the front tire is about 1mm narrower than the front rim’s external width and rear tire is about 0.5mm wider than rear rim’s external width so still sound aerodynamics.
the bike is a titanium all road/light gravel with room for 40mm tires, I just figured going as big on tire size while avoiding any ‘aero penalties’ would just work (and look) best with the bike and it’s geometry.

Does the bike on 32s feel more stable at speed and on non-technical sweeping corners? Bigger tire will increase fork trail which helps the bike feel stable at speed but slower/sluggish to turn in.

If you’re comparing a Super Six with 25s to a Super X with 32mms though you’re comparing apples to meatballs. The Super Six is Shorter, has a steeper HT angle, lower BB, less fork trail, is shorter in wheelbase. CX bikes always feel like garbage in the corners on the road to me. Kind of makes sense. Elite CX races they’re doing like 17mph, no need to compromise to make the bike also turn well at 30, that’s why gravel bikes exist.

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No, I absolutely also do.
Riding a 35mm René Herse on 23mm inner width rims. I feel like a drunk truck driver but it’s so nice on cobbles that I want to keep it.