Do slicks make a big difference to speed

[stevebills]

I was interested to no if I ran slicks that can haddle around 125 psi would this make a difference on a e-bikes or not?
I no e-bikes are heavy beast so surely slicks may help a bit.

 

[flecc]

Yes, but much depends on what you change from. If running good quality tyres like Continental or Schwalbe road tyres at present, slicks may make very little real world difference.

If changing from ersatz Chinese tyres, the benefit can be much greater, especially so if the existing tyres are offroad knobblies with poorly designed tread block placements.
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[overlander]

I run slicks right now and they do run smooth but any time gained is offset with the bike upside down changing the inner tube.

 

[Tex]

i notice a not insignificant range and speed difference (est. 15% ++) from my 100psi 32/700c slicks c.f. my Schwable Marathons 2.0's at 65psi. i alos like the "faster" feel of the narrow slicks (see pics below)

 

[Mussels]

I've not noticed much difference between tyres, even the studded winter knobblies. However my riding is a lot of stop/start stuff so if I had longer runs it might be different.

 

[piotrmacheta]

I lose about 2mph off my top speed when changing from slicks (on 700c wheels) to mountain bike knoblies on 26" wheels.

 

[BLACKPANTHER]

I think the bigger difference is due to width rather than tread pattern. I recently took the knobblies off the missus' mountain bike and replaced then with the standard road tyres that came with the Aurora. After the 1st ride she said she couldn't believe how much faster and easier it was to ride. I you want more speed, go thinner.

 

[stevebills]

i notice a not insignificant range and speed difference (est. 15% ++) from my 100psi 32/700c slicks c.f. my Schwable Marathons 2.0's at 65psi. i alos like the "faster" feel of the narrow slicks (see pics below)

I been getting 28 to 30 mph max with hard peddling on the flat with no headwind with this 600T on slicks and how does your 850xli compare?

 

[andrewgardner]

Wider tires roll faster than narrower ones: Riders have argued for years that narrower tires – especially on the road – roll faster and are more efficient than wider ones when in fact, the opposite is true. According to Wheel Energy, the key to reducing rolling resistance is minimizing the energy lost to casing deformation, not minimizing how much tread is in contact with the ground. All other factors being equal, wider casings exhibit less 'bulge' as a percentage of their cross-section and also have a shorter section of deflected sidewall a look at this..

 

[stevebills]

I found this info

Why do wide tires roll better than narrow ones?



The answer to this question lies in tire deflection. Each tire is flattened a little under load. This creates a flat contact area.

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

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

Rolling resistance:
At 2 bar a 60mm wide tire rolls as well as a 37 mm tire at 4 bar.

 

[Streethawk]

There's a lot of things affecting rolling resistance, tyre width, tread, pressure, the compound of the rubber, what its running on and contact patch. There are knobbly MTB tyres out there that roll pretty fast, Schwalbe Racing Ralph's for example, but TdF riders all use 18-23c tyres which have the lowest rolling resistances.

I rode 23c tyres for 18 months on my road bike. Bloody horrible, needed 120psi to avoid pinching and at that pressure had no give at all. Might as well have been solid.

 

[flecc]

in the wide tire, the radial length of the flattened area is shorter, making the tire rounder and so it rolls better.

This is the line that Schwalbe take on this issue, so I'm not surprised that the source is the USA.

As Streethawk says though, this is not a simple one factor issue, there are numerous factors involved and I don't see race bikes using wide tyres.

I agree that some knobbly tyres can roll well, resulting from a good tread block pattern of distribution, keeping the wheel at a constant height as it rotates.
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[Mussels]

As Streethawk says though, this is not a simple one factor issue, there are numerous factors involved and I don't see race bikes using wide tyres.

Like most aspects of bikes the UCI restrict tyre width so racers can't use wider tyres, killing innovation yet again.

Edit: bigger tyres are heavier and require more energy to get rolling, I much prefer them though due to the state of normal roads.

 

[piotrmacheta]

Tyres with knobbles create more wind resistance as they rotate. Maybe this would be noticable with a wider tyres.

 

[flecc]

Like most aspects of bikes the UCI restrict tyre width so racers can't use wider tyres, killing innovation yet again.

Good point, I'd hadn't thought of the retrograde UCI influence.

If Formula 1 administration was the same, Lewis Hamilton et al would be racing on narrow tyres and wearing leather flying helmets and goggles.

Still don't think the cycling race crowd would use fatter tyres though, due to weight, wind resistance and probably lower tyre pressure drag factors. Larger diameter wheels are a better route for maximising roundness and minimising rolling resistance to satisfy the Schwalbe thesis.

Bring back the Penny Farthing!
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[stokepa31_mk2]

pro time trial riders tend to go as low as 19mm width but on some of the classics like paris - roubaix you will see tyre widths of 25mm this is generally to make the ride more comfortable. tyre deflection is also influenced by the psi rating of the tyre too so if you can get a very high pressure narrow tyre you will ofset more of the deflection. rims are also just as important to rolling resistance both in weight and drag.

its a complicated area but as a rule thinner and higher pressure = faster.

downside is less comfort, more punctures and the potential to batter ones crown jewels lol

 

[mikep]

I've just picked up on this thread and thought I'd comment on my experience.

My BH came with 700x38 Cheng tyres which seem to roll OK at about 75psi, but the worry was more the durability/puncture resistance of the tyres.

SJS were selling a pair of 700x50 Schwalbe Marathon Supremes at about half price, so tyres and tubes were changed and run at just under 5 bar.

Result, speed/effort little difference, the main difference came with the feel of the bike and how it cornered, an amazing improvement, and the added comfort! With the Supremes it would possible to change the suspension forks for rigid, and get rid of the suspension seat post and still have a more comfortable ride over the original tyres.

 

[Deleted member 4366]

I run all my bikes on Schwalbe City Jets. They give a significant increase in speed, range and reduction pedalling effort compared with normal treaded road tyres. They're a huge amount more efficient than block pattern tyres, but not as good off-road, nor are they as good in the wet as other tread patterns.