Tire width and pressure for feather light riders

Discuss light weight issues concerning road bikes & parts.
eyedrop
Posts: 101
Joined: Wed Jan 27, 2016 5:33 am
Location: Prescott, AZ

by eyedrop

25 and 28c tires are basically the new standard, and there is plenty of evidence showing that they offer improved RR and comfort over the same 23c tire.

But what about with super light weight riders? All of the tests Ive seen are done using normal 150-200lb riders.

Im only 105lbs, and I noticed my 25c tires seem too wide for me. My pressure needs to be super low, which makes the tires feel squishy and not very efficient. It also makes the bike handle slow, and the bike has a general lack of road feel. The thinner tires feel faster on turn in. The 25c do roll nicely and are super comfortable, and I feel more grip for sure. But the bike just doesn't feel racey or efficient. The bike comes alive and feels aggressive with the 20c tires.

I feel like Im going faster on 20c or 23c tires, which despite the narrow width, I still only need 70-80 PSI for my weight. The comfort really isnt bad at all. A bonus is the 20c tires are super light weight and more aero on my wheels. So in my case, why run wider tires?

It seems like every article I read just toots the 25c horn, with no regards to what the weight of the cyclist is.

Any comments on this? What kinds of sizes and pressures do the world class Junior cyclists run?

alcatraz
Posts: 724
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

I'm wondering the same thing. I'm on 23's and weigh 125lbs.

Isn't that already optimal for me?

/a

by Weenie


sungod
Posts: 1462
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

crr will vary with road surface, material, different rim width, variation in tyre load and pressure, plus tyre construction itself if you're looking at different makes/models

on top of all that, there's the aerodynamic impact, could be worse if the tyre is wide and the rim narrow, i.e. what you gain on crr you may lose in drag, especially as the latter increases exponentially with speed

unless you've got a lot of reliable data on different tyres, i'd just go with what you feel best on

chiumomo
Posts: 75
Joined: Tue May 29, 2012 1:38 pm

by chiumomo

alcatraz wrote:I'm wondering the same thing. I'm on 23's and weigh 125lbs.

Isn't that already optimal for me?

/a


What pressure you run? I weigh 130lbs and I use Veloflex Carbon 23mm pump to 105-115psi when racing.
I did try to use the wider 25 mm Arenberg tubular but it always feels sluggish and slower, especially when out of saddle, feels like I have a flat tire sometimes. :noidea:

PinaF8
Posts: 186
Joined: Mon Jan 23, 2017 8:05 am

by PinaF8

I'm 135 on 25mm Conti GP4k S2 wrapped on Enve 4.5ses. I inflate them F90/R95, I could go softer but due to some poor road conditions I prefer a little more psi. I find it a bit subjective and psi will vary depending on training/racing conditions.
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Geoff
Posts: 5093
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

I am 132 (today, 128ish, race-weight). I prefer 23s, as well. For general road use, I like the 'feel' of them better than 25s for that purpose. I run them 100/115 front/rear for good conditions, and 10-20 psi softer in the wet.

I think the reason for 25s was originally the deeper rim beds of the new deep carbon wheels, which would cause pinch flats on the rears. I still run 25s on deep rears.

Today, people are running wider and wider tires for comfort and better rolling resistance (the softer, higher-volume tires roll better in the real world than hard, narrow tires), apparently finally figuring-out what tubular riders have known for decades. I think that 27s are great on pave wheels, but on regular roads, they are another hipster fad. I'll stick to my 23s and (and not put a chain on my wallet, either).

pdlpsher1
Posts: 1410
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

I'm 136 lbs and run 23mm front and 25mm rear Conti 4000S II. Both at 90psi. The weight diff between a 23mm and 25mm is less than 10g. I love the ride and handling using diff tire widths for front and rear.


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alcatraz
Posts: 724
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

chiumomo wrote:
alcatraz wrote:I'm wondering the same thing. I'm on 23's and weigh 125lbs.

Isn't that already optimal for me?

/a


What pressure you run? I weigh 130lbs and I use Veloflex Carbon 23mm pump to 105-115psi when racing.
I did try to use the wider 25 mm Arenberg tubular but it always feels sluggish and slower, especially when out of saddle, feels like I have a flat tire sometimes. :noidea:


I run 100-110 psi in the front and maybe 120-130 psi in the rear. I used to run 120-130 in both but I had an accident where I lost the front grip in a tight switchback and I think I probably went too high in front where I don't have as much weight.

/a

gsindela
Posts: 88
Joined: Fri Feb 10, 2017 8:48 pm
Location: Geneva, IL, USA

by gsindela

2015 Storck Scenero G3, Force 22, Ultegra wheels, Zipp AL bars, stem, post

AJS914
Posts: 1891
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

You guys run a lot of pressure. I'm a 200 pound guy (91 kg) a run 90-100psi in 23mm Conti GP4000s. I never get pinch flats. If I weighed 130 pounds I'd be trying 80-90 psi.

23mm Conti actually measure 25mm on my old school narrow rims. I tried 25s (measure 28mm) and handling was worse so I went back to 23s.
Last edited by AJS914 on Mon Apr 24, 2017 8:35 pm, edited 1 time in total.

bbqpork
Posts: 27
Joined: Fri Apr 24, 2015 4:38 pm

by bbqpork

I am 140lbs, riding on HED Jet4/6+ with 25mm Victoria Corsa G+ @ 75/85 psi.
Note: The tires measure 29mm in this setup.

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toshi
Posts: 258
Joined: Tue Jul 04, 2006 1:32 am

by toshi

136lbs/62kg. Rubino III 23s on old Scirocco 35s (15c internal 20.5 external). 85psi rear, 75psi front.

Hexsense
Posts: 340
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

even at 145lbs i use front at 60-70psi for 25c only. I could also run 23c at 70-75psi but my inner rim width is a bit too great and 23c on 21mm inner looks a bit unsafe.
For your weight i would probably go for 23c front and 25c rear at almost the same pressure of around 60-75psi -- test for yourself as rim also play big role to pressure needed if your rim get reasonably aero with 25c tire at all.
But if your rim is also very narrow then maybe 20c front and 23c rear or 23c on both and lower pressure for front wheel.
I don't recommend 20c in the rear at all. You are blessed that you can run low pressure which roll nicely on bad road unlike high pressure tires which will bounce you all over the place. Take advantage of that as light riders tend to suffer from bad road and cross wind more than heavier guys.

Hexsense
Posts: 340
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

Another add: big tire at low pressure do roll well straight line.
But handling in corner might suffer if the rim inner width is not big enough to provide solid stable platform for the tire. Increase pressure solve this problem but that's far from ideal and kill the reason to use wide tire in the first place.
Ideal combo would be 23c (or 25c) on 19mm inner width rim and 25c (or 28c) on 21mm inner width rim.
https://intheknowcycling.com/2016/04/03 ... eel-sizes/
Last edited by Hexsense on Mon Jun 12, 2017 4:41 am, edited 1 time in total.

by Weenie


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TonyM
Posts: 1809
Joined: Thu Jan 22, 2015 4:11 pm

by TonyM

My Veloflex tires state 6 to 9 bars. I suppose at least 6 bars in order to have an adequate handling when cornering.

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