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so I have converted my disc brake Road Bike to rim brake. My road bike frame is thru axle but it has a slot for rim brake so i decided to go for rim brake and I removed the rotors from the hub and planning to put a colored bolts for the rotor slot (just for the design). Is this build okay?

Close-up of front brake; it is printed SHIMANO Rear triangle showing rear wheel and rear brake Close-up of rear brake; it is branded ULTEGRA

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    Could we have some photos please ? use edit to add them. I'm looking for a brake track on the rim, and proper caliper mounting holes, and that your pads match your rim.
    – Criggie ♦
    Aug 10, 2021 at 19:39
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    If you know how to do it it is fine. It is quite expensive to have someone to do it for you.
    – Vladimir F Героям слава
    Aug 10, 2021 at 21:47
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    Without meaning offense, I wonder if there is a language barrier here. If the shop actually said that the rim is fine for rim brakes because it's an "alloy", they are mistaken. It needs a brake track. You can make a carbon rim with a rim brake track. For that matter, I bet you could make wood or steel rims with brake tracks, but they probably don't work as well. The rim you linked to that you said you ordered is clearly a rim brake rim. However, you can't simply transfer the spokes, you need to calculate the correct spoke length for the new rim and the old hub.
    – Weiwen Ng
    Aug 10, 2021 at 23:00
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    @Kant - spokes are specific lengths to match the geometry of a rim. Unless the new rim has the exact same profile, which unlikely, then you'll need different spokes too.
    – whatsisname
    Aug 11, 2021 at 6:22
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    Also why are you doing all this in the first place?
    – whatsisname
    Aug 11, 2021 at 6:23

1 Answer 1

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It is of course in general OK to but rim brakes on your bike IF the frame supports them and IF the rim has the braking surface. You will need the right brake levers and cables. If your disc brakes were mechanical, they may or may not use the right actuation ratio - depends on the kind of rim brakes (road, V-brakes, cantis,...).

But I do not think we can say more from your brief description.

Thru axles are irrelevant. Or at least they do not interfere with rim brakes in any way.

Update: Your old wheel rim does not appear to have the braking surface and is thus incompatible with rim brakes.

Update2: The new Cosmics should be OK.

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  • And from what I've understood from an engineer explaining on YouTube, the holding power on a QR is 10X higher than that of a thru-axle.
    – Carel
    Aug 10, 2021 at 17:31
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    @Carel: it's not really meaningful, as QR are plenty capable of holding the wheels in. The main difference is in the failure mode if the QR or TA is improperly installed, TAs are more tolerant of user error.
    – whatsisname
    Aug 10, 2021 at 20:26
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    Good job pointing out that disc rims typically don't have brake tracks that rim brakes would grasp on. I had wondered about this myself.
    – Weiwen Ng
    Aug 10, 2021 at 21:32
  • Thank you for helping sir and the other guys as well 😅☺️
    – Kent
    Aug 10, 2021 at 21:47

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