Tech The case of wider rims for road bikes

Gok

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Dec 22, 2016
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As the thread name suggests:

Looking to hear from TCC members who have gone with wider rim wheelsets.
- Do you feel a difference between 15C, 17C, 19C; especially when running 25 mm or 28 mm tires (Talking to caliper brake gang)?
- Can you squeeze in a wider tire in the limited clearance, road calipers have to offer just by going with a wider rim (By changing the tire profile)?
- Any suggestions on specific brands (budget friendly)?
 
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Karl

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I had Shimano R500 wheels (15mm internal rim width) on my Surly. I put 35mm tires on them and it worked but looked like a light bulb shape. Bought some wheels with 18mm internal width and it looked like it was a better fit for the tires. Not sure I could tell if there was much difference in the ride between the 15 and 18 rim width. Most of the difference in ride came from running lower pressures. I now have Gravel King 700x43s on the Surly and they also fit OK on the 18mm rims. (Shimano XTR mtb brakes so I have to undo the cable to open them wide enough to get the tire through).

On the Cannondale CAAD road bike, I used to ride with 23mm Gatorskins on my R500s (15mm internal) and run them at 100 psi. A bit harsh. I switched to 28mm Gatorskins and dropped to 80psi and the ride was much smoother. When I put 18mm internal rims with the 28s, I didn't notice much difference from the 15mm internal as long as the PSI was dropped to 80 or so. I now have Hunt Aero Race wheels with 18mm internal rim width on my new bike and Gatorskin 28 tires. Very comfortable ride.

I can get the 28s on my Cannondale with little to no problem clearing the brakes (Shimano 105s). I doubt you'd be able to go to 30s or 32s and get past the brakes or clear the frame.

Still haven't gotten up the courage to go tubeless, but everyone says they will give you the best ride because you can run them at much lower pressures.
 
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OreoCookie

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Dec 2, 2017
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I wouldn’t want to put anything narrower than 28 mm on my bike.The difference in comfort between 25 mm and 28 mm tires run at equivalent pressures is substantial. Plus, you can run at much lower pressures in case you want to maximize grip rather than minimize rolling resistance. The limiting factor will be frame clearance. As a rule of thumb: the older your frame, the more limited your clearance will be. If you have rim brakes, the clearance will be smaller compared to an equivalent disc frame. In my disc frame I am sure I could fit 32 mm tires in the front, but in the rear 30 mm is probable the absolute limit (with my 28 mm tires, I have small clearance, so if I were to pick up debris from the road with even wider tires my frame would get scratched).

I don’t have experience with narrow wheels, though, but clearly, the wider your wheels, the wider the profile of your tire tends to be.

And note that what matters in reality is the actual width rather than the quoted width. Especially up until last year, tires tended to be actually wider than what was quoted on the box.

Lastly, I really recommend spending money on good tires. More expensive tires tend to be more supple and offer substantially better grip when you need it and lower rolling resistance. The difference is significant even if the tires look almost the same. Gatorskins are much slower than GP5000s. My Vittoria Corsa give me a magic carpet ride, my Corsa Controls offer great grip in the corners during the off season.
 

MattRyuu

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Apr 23, 2019
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Went to 28 from 23 and boy, what an amazing difference. I did a substantial amount of research on this topic and one of the better sources was intheknowcycling.com as a starting place for rim research. As @OreoCookie said, the big thing is frame clearance. The regulars around here recall my issues with getting the calipers to fit around some pretty wide and deep carbon rims I bought. Also will echo getting good tires. The GP5000s are comfy and fast.
 
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speedwobble

Speeding Up
Jun 26, 2017
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The bicycle rolling resistance website who tests tyres with a drum also has measurements of actual width. Only one tyre on one rim, but it's better than nothing. If you're pushing it with frame or brake clearance on a road bike, you might be better off with a big 25 (Conti GP4000s etc.) or narrow 28 than a regular or big 28. You don't want to buy something that won't fit. I think Specialized also make 26s if you are in between.
 
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TheAussieinJapan

Speeding Up
Apr 15, 2014
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Nerima Ward
I’ve got Continental Gatorskin Hardshell 32s on my new Trek Domane with 21mm rims and it’s amazing how much more noticeable the ride comfort is over my Continental 25s and is even faster as I'm rolling right over bumpy stuff and not losing any speed Or stopping peddling over anything rough.

Tyres being the main contact point with the road I don’t mind spending a little more money but I also like value. Continental 4000’s are great value now that the new model is out, however I think the extra sidewall protection on the GatorSkins are a good choice.


The other tyres I used WTB but they might not have a lot of 28mm.
 

Slowburner

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Sep 27, 2019
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I happened to watch this today, a comparison of narrower race tyres versus wider gravel tyres, by Global Cycling Network which was pretty good. They ran both sets at different pressures, and their guy spun them up to 45kmph and they measured the power required to do so. Interestingly, he couldn’t manage the distance on the low pressure wide tyres. And this one, which is right on topic wider rims and wider tyres
 
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speedwobble

Speeding Up
Jun 26, 2017
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The GCN video is interesting in that the road tyre is also faster on the smooth gravel they test. Deflection from the uneven surface does not slow it down. Only one test of course, and the ride quality will no doubt be worse.
 

sean-e

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Mar 4, 2019
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大田区
Looking to hear from TCC members who have gone with wider rim wheelsets.
- Do you feel a difference between 15C, 17C, 19C; especially when running 25 mm or 28 mm tires (Talking to caliper brake gang)?
- Can you squeeze in a wider tire in the limited clearance, road calipers have to offer just by going with a wider rim (By changing the tire profile)?
- Any suggestions on specific brands (budget friendly)?
A while back I was curious about this too and measured it. On my prime pro road wheelset with a 17mm internal rim width, a conti gp 4k in 28mm measured 30mm wide. On my HED Ardennes Plus wheelset with a 21mm internal rim width, the same tire measured 31mm wide. So, not much difference 🤷‍♂️
 
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TheAussieinJapan

Speeding Up
Apr 15, 2014
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Nerima Ward
I happened to watch this today, a comparison of narrower race tyres versus wider gravel tyres, by Global Cycling Network which was pretty good. They ran both sets at different pressures, and their guy spun them up to 45kmph and they measured the power required to do so. Interestingly, he couldn’t manage the distance on the low pressure wide tyres. And this one, which is right on topic wider rims and wider tyres
Check out this podcast which has a bit more detail that covers more than rolling resistance. The GCN episode was good, but this podcast below was one that gave me a lot to think about for tyre choices.


“Can’t quite allow yourself to believe that a 30mm tire at 70psi might be faster than a 23mm one at 100psi?“