I use Schawlbe Durano Plus 700X23C on Bontrager TLB 622 X17 ERD rim and want to change to a thinner tire as a 21C Can I make this tire change on the same rim? If this is possible wich tire brand? TKS

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    As the two widths are so close to each other, I suspect you'll be ok, but strictly speaking you should check whether the rim supports the smaller width.
    – PeteH
    Commented Dec 5, 2016 at 10:39
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    As an aside, why narrower? Most are moving to wider as they have been measurably shown to be faster and more comfortable.
    – Rider_X
    Commented Dec 5, 2016 at 17:37
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    You should get a ruler and measure the external rim width, from one braking surface to the other. You'll have to "eyeball" it, but you should come within 2mm or so. The internal width will be about 5mm less than the external. 15mm internal width would be about the max you should attempt with a 21mm tire. Commented Jan 4, 2017 at 23:37

1 Answer 1


If 17mm is the internal width, 21mm tires are probably a bad idea. According to Sheldon Browns (admittedly conservative) chart, 25mm is the lowest recomended width on 17mm rims. You could also probably contact Bontrager and ask for this specific rim though.

As an aside, I'm not totally sure why you'd want to use 21mm tires. Barely anyone makes them anymore, they're less comfortable and have higher rolling resistance.

  • I can't find the specs anywhere, but in my experience rim manufacturers often quote the external rim width, vs internal. Commented Dec 5, 2016 at 18:16
  • If TLB was a typo for TLR, then looks like it's something like this (www.trekbikes.com/us/en_US/equipment/cycling-components/bike-wheels/bontrager-race-tlr-road-wheel/p/11063/) rim, which is listed as 23mm outer, 17.5 mm internal. If 17mm is external, the inner width would almost certainly be 14mm or lower, so just fine.
    – Jamie A
    Commented Dec 5, 2016 at 18:32

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