which tire on rim

Back by popular demand, the general all-things Road forum!

Moderator: robbosmans

Post Reply
Timmy269
Posts: 243
Joined: Tue Nov 25, 2014 2:34 pm

by Timmy269

Which tire size would be the best on a rim with internal width 15mm en external width 21mm.

I doubt between the Specialized Turbo S-Works 24mm or 26mm.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



bm0p700f
in the industry
Posts: 5777
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

Either.

User avatar
Beaver
Posts: 796
Joined: Wed Aug 18, 2004 6:06 pm

by Beaver

The narrower the better. Best performance would even have a 20mm tire, but comfortwise nobody likes to ride these anymore.

A wide tire on a narrow rim looks like a light bulb - the flanges are bent and a high pressure is needed to make it roll and be stable. If you run a low pressure for comfort it will feel squishy and have a higher rolling resistance.

But also 15mm inner width rims are hard to get these days, so this will adjust over time. ;) 21mm inside will be more common in the future. Problem is that older frames won't fit these and narrower rims will have to stay availiable for a certain time.

User avatar
vejnemojnen
Posts: 406
Joined: Fri Nov 08, 2013 7:11 pm

by vejnemojnen

Get a new wheelset with 19mm inner width rims, and use 23-24mm tyres. :beerchug:

please, read this:

https://intheknowcycling.com/2016/04/03 ... eel-sizes/

zefs
Posts: 436
Joined: Sat Aug 05, 2017 8:40 pm

by zefs

Best for what use? wider tires for comfort, narrow for aerodynamics. I would go wider for the comfort since if you care about aerodynamics you need to optimize the rest of the setup and tires would be at the end of the list for aero gains.

alcatraz
Posts: 4064
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

If you are a heavier guy I doubt you will be pleased with any tire on such narrow rims.

If you are a light guy then do 23/25.. or 25/28.. front/rear.

Just a suggestion. It helps to keep weight down and aero up while preserving some comfort.

Timmy269
Posts: 243
Joined: Tue Nov 25, 2014 2:34 pm

by Timmy269

So my rims are to narrow for tires +25mm.
I didn't know that they are so narrow, that the rims today are minimal 19mm internal width.

I don't need more comfort but I have read that everybody fits larger tires on the rims, because it benefits less resistance.
Now I have the 24mm sworks on them.

alcatraz
Posts: 4064
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Wider tires come with an aero penalty.

If you are a lighter guy you might actually become slower by fitting wider tires. Then pehaps the aero penalty is greater than the rolling resistance benefit.

Optimal is to use a rim width that suits your body weight and tires that suit that rim width. 15mm internal is maybe optimal for 40kg riders with 19c tires on. :lol:

So in essense, only go as wide as you need. Wider is not always better. It's just a lazy interpretation of what some some people observe is happening.

bm0p700f
in the industry
Posts: 5777
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

your rims are fine with 30mm tyres it just wide tyres will ballon a bit. that has performance implications but its not unsafe. your question was is o.k with 26mm and yes it is.

Since both tyres will ballon i dont think there is going to be performance gain with the 24mm.

User avatar
Beaver
Posts: 796
Joined: Wed Aug 18, 2004 6:06 pm

by Beaver

The differences are not huge and people rode 23/25mm tires on 15C for years, it's just not the best performing combination.

And a wider tire has a lower rolling resistance on the same rim at the same high pressure. But because of the higher volume the tire gets less comfortable and people run lower pressures which compromises handling and rolling resistance. For 28mm comfort and 25mm speed you could run a 25mm tire on a 21C rim with low pressure. A 28mm tire on a 15C rim is of course possible and will be more comfortable, but performs worse - higher rolling resistance and a squishy feel.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



Post Reply