How much do tires affect speed?



JoelTGM

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Oct 21, 2010
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I used to get flats every week on the crappy trails I rode, so I got thick tires with kevlar in them, and since then I've never had a flat. Nowadays I ride a paved trail though, so I don't think I even need them anymore, and the other day at the bike shop I was putting together these basic commuter bikes with thin tires and I realized they were lighter than my bike. So what do you guys think about this subject? Do lightweight road tires make much of a difference to the average joe on a bike? I've had trouble keeping up with this guy on a mountain bike before, although he was much stronger than me, but it still makes me question whether or not tires affect speed much. The reason I'm asking this is because I LOST my road tires because I'm an idiot, so I can't just swap the tires out to see what the difference is.
 
If you're riding a road bike and concerned about speed, there can be a significant differential from tire to tire in terms of wattage required to sustain the same speed. Said another way - for the same effort (aka wattage at the hub or crank), you will be going noticeably faster on some tires than others. Vittoria, to name one manufacturer, makes some of the "fastest" tires on the market today...

It is also true that putting more air into your tires decreases rolling resistance/increases speed for the same effort. However, it doesn't sound like you're riding on very smooth pavement...
 
It's smooth pavement that I ride now, but I used to ride gravel so that's why I got these thick tires. So do you think thinner and lighter tires could maybe give me +1 km/h to my average speed or something like that? that'd be significant enough.
 
Definitely!
Put some relatively high performance 700x25 tires on your bike and you'll think you died and went to heaven with the increase in performance you'll see versus your thick, heavy tire set-up. If you don't see 3kph+, I'd be suprised...
 
man I'm tempted... I wish I knew where the heck I put those tires. I can't really afford new tires because I just had to buy all new gear after an accident, and just today I left my seat pouch unzipped, so a couple tools fell out. I dunno we'll see.
 
tires make a huge difference. I'm a clyde so my body weight is a ton but i definately notice a difference with lighter tires. I used to have Armadillos on road bike because they could handle higher pressure than cheapo tires which i needed weighing 235 lbs and they had kevlar in them. They weighed close to 500 grams. I then switched to continental gatorskins which are also pretty flat proof but also have a kevlar bead instead of steel so they are the "folding" version. those tires only weigh about 250 grams, it's a very noticeable difference. Gatorskins are pricey but panaracer pasela TG are pretty nice and light and only about $25 each
 
Originally Posted by Yojimbo_ .

I found this on the web after an exhausting 10 second search.

http://www.terrymorse.com/bike/rolres.html
Good matrix. I do not use a wattage meter or any form of tracking wattage in my training. How noticable is 20 watts? I recently purchased a pair of Hutchinson Top Speed at a good price and have not put them to the pavement yet. I purchased them because of my luck with the Fusion line in the past. Both of these tires are in this case study with the Top Speed coming in last. Should I even be concerned seeing as the tires in this study all appear to be premium tires?
 
Originally Posted by davereo .



Good matrix. I do not use a wattage meter or any form of tracking wattage in my training. How noticable is 20 watts? I recently purchased a pair of Hutchinson Top Speed at a good price and have not put them to the pavement yet. I purchased them because of my luck with the Fusion line in the past. Both of these tires are in this case study with the Top Speed coming in last. Should I even be concerned seeing as the tires in this study all appear to be premium tires?
Here's the source:

http://www.rouesartisanales.com/article-1503651.html

20 watts is noticable... however, I didn't notice a mystical jump in speed for the brief time that I spend on Vittoria Open Corsa CX's rather than the Conti Attack/Force combo I was running at the time. The only thing I noticed was that I ended up on my ass for the first time in years courtesy of lack of mid corner grip and a batch of punctures with the CX's.

What's more noticable are punctures. The link I pasted included a reference to puncture resistance and I can say first hand from experience with Vittoria open CX's and the Schwables that came with my Cannondale that the verdict of low resistance to punctures is correct...

On tires with a fairly high thread count casing (ie ones that are supposed to be more supple) a reasonable reduction in rolling resistance can be had by switching to latex tubes.

Tire pressure is a compromise. Do you run 9+ bar and bounce all over the place or do soften things to a more reasonable pressure. Of course this depends on whether you ride on really smooth roads that won't cause your "wedding tackle" to be battered and bruised...

... but a good tubular inflated to 170psi when ridden on concrete sounds Godly.
 
The entire tire round-and-round is tired...

Ok - got that out of the way. Here's my take on tires after reading a lot and riding some more:

Tubulars with latex are going to be fantastically light, fast and supernatural in power-transfer and spin up - just don't get a flat unless you ride with a support vehicle ALL THE TIME. Changing a tubular on the side of a road - no fun. Also - if you're riding clinchers you'll have to switch everything. Also - latex tends to blister more easily, but is more resistant to puncture...?? Less or more?

On the topic of inflation - some deflection in the tire is a good thing when not riding on smooth or very smooth surfaces, where very smooth would be track conditions (velodrome). Meaning that letting the tire deflect over road imperfections will give a smother roll and more comfortable ride - less fatigue to the rider = faster. So riding a tire rated at 145, filled to 145psi will rattle over chipseal and gravel, letting it out a bit to say ~ 120psi will roll more smooth...

More than strict wattage comparisons, weight and the rest of the list of variables associated with how great a tire can preform is the condition of road, type of race and style of rider on them. A crit will call for a better cornering tire where a century through the country will be less corners and more rolling.

I am currently riding Vittoria on Mavic Ksyrium Equipe - and I weigh in at 195lbs but can climb like a goat, according to my coach.
 
Originally Posted by MichaelVahlsing .

The entire tire round-and-round is tired...
Hey, that's pretty good. Think of it yourself?

Anyway, thanks for the contribution. Y'ever consider the saying, "if you're not part of the solution, you're part of the problem"?

Just to let you in on a little secret, everything you said has been said on this forum MANY times over - nothing evolutionary, revolutionary, nor earth-shattering in your effort...

Oh yeah, welcome to the forum...
 
Originally Posted by tonyzackery .




Hey, that's pretty good. Think of it yourself?

Anyway, thanks for the contribution. Y'ever consider the saying, "if you're not part of the solution, you're part of the problem"?

Just to let you in on a little secret, everything you said has been said on this forum MANY times over - nothing evolutionary, revolutionary, nor earth-shattering in your effort...

Oh yeah, welcome to the forum...
lol kind of alienator's job don't you think?
 
20 watts for someone riding at 200w reduces his speed from 20mph to 19mph.

20 watts for someone riding at 400w reduces his speed from 27mph to 26.5mph.

Going from trail tires to road tires might save 20watts, but there is little chance that changing between different road tires will save or cost you 20 watts.
 
Originally Posted by finnrambo .



lol kind of alienator's job don't you think?
LOL! The ol' alien one was a fairly capable and gracious ambassador who always warmly welcomed omniscient newbs to the cycling forums. That's been my recollection of his legacy. That jive with yours?/img/vbsmilies/smilies/biggrin.gif
 
Hello:
Can some body explain "TPI" or rubber compound, how it makes the difference in price and in performance,AND WHAT OPINION do you have about tufo tires,i just put a pair
and I instantly notice a hell of a positive difference they can handle 175-220 psi/img/vbsmilies/smilies/icon14.gif
Thank´s
Rondevouz
 
Threads per Inch is use to describe the casing fabric of a tire. Finer TPI is supposed to imply a thinner and more supple casing, ie, more of a race tire. For multi-layer casings, eg, Conti, believe the total TPI of all the layers is often advertized, ie, 120 tpi/ply x 3 plies = 360 tpi.

Bottom line, don't think the TPI indicates much about the quality or puncture resistance of a tire, or tells you if the tire is right for your needs. Same goes for any description of rubber compounds. Conti and Michelin, maybe others, have some good selection info on their websites which compares their various offerings.

Ultra-high pressure tires sound cool, but may not mean anything in real-world performance on real roads (vs a smooth board track). Also, if you're talking clincher tires, the rim has pressure limits.....believe Mavic rates many of their rims @ 140 psi max.
 
dhk2 hits a good point with the rim pressure issue. You don't want to be around when a rim separates! It gets damned ugly fast.

If you're riding on roads with any debris (and no support, car/team/otherwise), you might want to consider reducing your air pressure. A slightly softer tyre will roll over some sharp items, whereas a highly-inflated tire, being hard, will provide resistance, and may puncture. If you're training, watch your HRM to see how hard and smart you're training, not necessarily how fast you're traveling. Race day is the time for increased tyre pressure.

just my 2¢ worth
 

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