Aero Disc wheelset for 25mm tires

Discuss light weight issues concerning road bikes & parts.
bikesrdangerousmmk
Posts: 104
Joined: Thu Jul 30, 2015 3:54 am

by bikesrdangerousmmk

Where are you gents and ladies currently leaning for performance and value ? Looking to build a race frame from parts primarily for crits and fast rides lasting no more than an hour.

bikesrdangerousmmk
Posts: 104
Joined: Thu Jul 30, 2015 3:54 am

by bikesrdangerousmmk

Anyone have experience with the Reynolds Ar(x) 58/62, HED Vanquish, or I9.65?

by Weenie


bm0p700f
in the industry
Posts: 4775
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

Well a 25mm tyre is going to be a width that wont be 25mm and that will depend on the internal width of the rim.

So lets give an example. The conti GP5000. On a 20mm internal width rim the 25mm tubeless tyre is 26mm wide. So ideally the rim external width needs to be 27mm or a bit wider. Tyres with bigger bead to bead distance need even wider rims but then the tyre spreads more.

So the answer depends entirely on the tyre your thinking about using.

alcatraz
Posts: 2057
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

I'd stay around 50/60mm and focus on tubeless. Here are my thoughts.

You need grip and low rolling resistance, low weight and aero are secondary since it's mostly flat and you'll be riding in a group.

Decide what real tire width suits the riding you'll do. By that I mean, hows the road quality? How much do you weigh? Are you in need of extra grip?

Smooth roads - 65kg rider - normal grip = ~23-25 mm front tire.

Rough roads - 80kg - normal grip = ~26-28mm front tire.

Get a rim that matches the chosen tire width. The width at the brake track is more important than any bulge at the middle. Go too wide and you lose out on aero, go too narrow and you miss out on rolling resistance.

Note that 26mm doesn't mean 26C and so on. It's all about the real width.

If you find yourself struggling more with acceleration than to keep pace, maybe tubular could be better. Slightly higher rolling resistance but easier to accelerate.

bikesrdangerousmmk
Posts: 104
Joined: Thu Jul 30, 2015 3:54 am

by bikesrdangerousmmk

Thanks. Leaning toward using Pro Ones or Conti 5000s. Will have decent road quality for their use.

What actual width are you typically seeing for one of those tires in nominal 25 width when inflated on a 19 vs 21mm internal rim?

alcatraz
Posts: 2057
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

All brands are different in real width. There is no typical other than they usually measure wider on modern rims.

There are exceptions though. Vittoria measures narrower. A 25c vittoria is narrower than a 23c Conti.

Pick your tire, then ask around what size you need in order to obtain a certain ideal width for you. You need to decide what your ideal rim/tire width needs to be and think carefully because you can't easily change it later. Optimum rolling resistance lies around 90-100psi on smooth roads. Lower on rougher roads. If you are used to pumping over 100psi you'll have a hard time deciding your ideal width.

Don't be the guy that reads the number off the tire and try different brands, then compare. To fairly compare two tires they should be of similar real width. :D

Also worth thinking about is you'll have more weight on your rear tire. To stay within 90-100 psi you might need a wider tire there compared to the front.

bikesrdangerousmmk
Posts: 104
Joined: Thu Jul 30, 2015 3:54 am

by bikesrdangerousmmk

alcatraz wrote:
Tue Jan 29, 2019 2:55 am


Pick your tire, then ask around what size you need in order to obtain a certain ideal width for you. You need to decide what your ideal rim/tire width needs to be and think carefully because you can't easily change it later. Optimum rolling resistance lies around 90-100psi on smooth roads. Lower on rougher roads. If you are used to pumping over 100psi you'll have a hard time deciding your ideal width.

Don't be the guy that reads the number off the tire and try different brands, then compare. To fairly compare two tires they should be of similar real width. :D

Also worth thinking about is you'll have more weight on your rear tire. To stay within 90-100 psi you might need a wider tire there compared to the front.
Hey, see above. Looking at conti 5000 or Pro Ones if you have specific input there. Appreciate your time.

alcatraz
Posts: 2057
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

They are both brands that measure wider, conti possibly moreso than schwalbe. Still probably not enough to warrant a difference in choice between those two.

Check the real measurements on www.bicyclerollingresistance.com

Both tires have been tested there.

25c-5000tl on a 17c rim measured 26.8mm

25c pro one on a 17c rim measured 27mm

If your rim is wider than 17c you can expect the tire to increase in width too.

Lets say you get a 25mm rim thats 18c. That means if you ride smooth roads and don't weigh over 75kg you should get a 23c tire to obtain a 25.5-26mm measured width. 5000tl and proone would appear to balloon similarly.

Sure a ~26mm tire on 25mm rim isn't perfect but it's pretty good.

For the rear wheel you might want to run a 25c tire or a wider rim to get a bit more support.

bikesrdangerousmmk
Posts: 104
Joined: Thu Jul 30, 2015 3:54 am

by bikesrdangerousmmk

Great info. Thanks.

bikesrdangerousmmk
Posts: 104
Joined: Thu Jul 30, 2015 3:54 am

by bikesrdangerousmmk

So, after looking at your link (and others, including: https://www.aero-coach.co.uk/gp-5000-tubeless-data ), and based on my weight being around the 80kg mark, I think I'm going to need to go with the 25s, which makes me think I'm looking for a rim more in the ~30-31mm width range. I know the Hed Vanquish and the newer i9.65 (https://industrynine.com/road/i965-disc) look like they could fit the bill.

Does anyone have any experience with those rims/wheels or other recommendations to check out? Thanks.

Marin
Posts: 3431
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

I'm almost 80kg (in WInter) and my "fast road" wheelset is 26mm wide at the brake tracks. I rund 23mm Pro Ones on the front that measure 25.5mm inflated - perfect match to the rim. 25mm in the rear, comes out to around 27mm.

Do you need a tire that says 25mm on it or do you want to ride a tire that is 25mm wide and aero? If the latter, you'll need a tire labeled 23mm unless you get something like a Veloflex which run true to size.

Don't forget that very wide wheels are slower at low yaw angles - there's a reason pro teams run narrow setups in TTs.

bm0p700f
in the industry
Posts: 4775
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

Between the conti and the schwalbe the conti gp5000tl is the better tyre in every way.

I have already told you how wide they are and suggested a rim width. On my Borg45disc rims they are just under 26mm wide for a 25mm tyres and the rim is 26mm wide. Obviously I would suggest these but there are others of course.

bikesrdangerousmmk
Posts: 104
Joined: Thu Jul 30, 2015 3:54 am

by bikesrdangerousmmk

Anyone have something to quantify different between actual 23 vs 25 vs 28 on the same and series of rims? I’ve seen a couple charts (can’t find them again) that showed a difference of around 3-5 watts max between an actual conti 4k 23 vs 25 and actual 25 vs 28. I’m not sure at what speed they were testing though. This was also on rims that were in the 28-31 mm wide range.

bikesrdangerousmmk
Posts: 104
Joined: Thu Jul 30, 2015 3:54 am

by bikesrdangerousmmk

bm0p700f wrote:
Tue Jan 29, 2019 7:48 am
Between the conti and the schwalbe the conti gp5000tl is the better tyre in every way.

I have already told you how wide they are and suggested a rim width. On my Borg45disc rims they are just under 26mm wide for a 25mm tyres and the rim is 26mm wide. Obviously I would suggest these but there are others of course.
Those looks very nice.

by Weenie


bikesrdangerousmmk
Posts: 104
Joined: Thu Jul 30, 2015 3:54 am

by bikesrdangerousmmk

Marin wrote:
Tue Jan 29, 2019 7:42 am
I'm almost 80kg (in WInter) and my "fast road" wheelset is 26mm wide at the brake tracks. I rund 23mm Pro Ones on the front that measure 25.5mm inflated - perfect match to the rim. 25mm in the rear, comes out to around 27mm.

Do you need a tire that says 25mm on it or do you want to ride a tire that is 25mm wide and aero? If the latter, you'll need a tire labeled 23mm unless you get something like a Veloflex which run true to size.

Don't forget that very wide wheels are slower at low yaw angles - there's a reason pro teams run narrow setups in TTs.
What rims are you using?

Other main concern beside being an aero weenie is being sure the setup will handle lots of turns without being squirrelly.

Post Reply
  • Similar Topics
    Replies
    Views
    Last post