I bought a pannier rack but it seems way too narrow to fit on my MTB bike (in terms of the axle width), I can sort of push apart the two legs (of the rack) but even then the spacing is only 10CM (when streched) between both legs which seems a 2-3cm too narrow for what is required.

Potentially this has been bent during transit - but I'm not entirely sure and thought to confirm in case I bought a wrong item.

Is there a standard set of sizes? What are they?

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  • 2
    Can you add a photo of your rack? It sounds far too small. or possibly its a rack for the front wheel.
    – Criggie
    Commented Aug 3, 2021 at 2:21
  • That rack looks like it could be flexed by 2-3 cm without damaging anything. Commented Aug 4, 2021 at 12:51
  • Yup seems to strech fine to about 10cm, but any further than that and it feels like it could be reaching a critical point of breakage. Not something I'd personally want to risk considering a load could potentially further stress it. None the less I've gotten a refund for this from the seller. Commented Aug 4, 2021 at 19:26

2 Answers 2


That rack has been crushed, presumably during shipping. For a rear wheel it should be somewhere between 120mm and 135mm between the axle mounts, with perhaps 5-10mm additional tolerance for going outside the dropouts.

A front rack would be a little bit less - most front dropouts have an OLD of 100mm.

That yours measures at about 70mm means something's off. Check the angles between each side and the deck - it should be symmetrical. Or stand the rack so both axle mounts are on the floor which should leave the deck level side-to-side.

Whether you can cold-set the rack depends on if it is steel (maybe) or aluminium (probably not) If you just bought it, talk to the shop and ask about what happens with shipping damage.

Since you paid retail-new price, you expect a good useable part to arrive. Is a different matter if it came from the $1 bucket at the local swap meet.

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    Yeah I think it's quite likely to be either damaged in transit or just a manufacturing defect. It is aluminium which makes me cautious about applying too much force. Helpful answer, thanks! Will probably be sending this back. Commented Aug 4, 2021 at 11:34

Tubus has some nice technical drawings for all of their racks: https://www.tubus.com/en/products

They also state the allowed width. For the classic model rear racks it’s from 150mm to 180mm. For the newer models it’s 140mm to 170mm. It doesn’t look like they are offering “wide” or “narrow” racks.

Pletscher states all kind of dimensions but not the allowed width.

I don’t think there is a “standard” size. But rear dropout spacing pretty much only goes from 126mm to 142mm (157mm for super boost). The mounting holes for racks will have a similar deviation (just add ~20mm or so for the seatstay width) so it’s relatively easy to support all of them.

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