Is it feasible to jerryrig a motorbike saddlebag as a bike pannier?

Question

There’s a used rear bike rack and a used motorbike saddle bag people are selling in my area. I already set up a time and date to pick both up before I realized that this bag was for motorbikes, but I think I may still be able to make it work.

This saddlebag is long (~22 inches, 56 cm) and the gap between the bags is a lot longer than the width of a standard bike rack. I think with enough zip ties etc I may be able to attach these bags to a rack, but idk how good of an idea this is. The weight distribution and size may be a problem for instance, I don’t see any bike panniers this long.

Has anyone happened to have done this before? Or anyone here that’s ever used a bike pannier or rack have any ideas why this should or might not work?

I appreciate y’alls time. Here’s the images

I tried to find measurements for the bag, all I found was the 22 in but I can ask the seller to measure it for me

Answer 1

Motorbike kit is surprisingly similar in general design to bicycle kit, but is generally more stoutly build.

A motorbike pannier will be used at speeds of 50-100 km/h and has to survive the driving rain at that speed, compared to a bike that might do 20-30 km/h

The downside of this robustness is that motorbike parts are heavier and tend to be larger. The size might work for carrying larger loads, but the underlying challenge is the weight.

A motorbike has anything from 3 to 300 horsepower (2,000W to 220 kW) where a cyclist is well under 1 horsepower (750W) so the extra mass is less important on a motorbike.

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I suggest that if you can back out of the purchase without penalty, do so.

If you're stuck with the bags, look at ways to adapt them to your bicycle. Ideally in a way that is reversible, so that a future motorbike owner might undo some stitching and get them back to original. I'd suggest not cutting anything if you don't absolutely have to, and if you take off any fittings, then store them for future reuse.

Its possible you will have to extend your rear rack, or adjust hooks. Motorbikes do not suffer from "heel strike" in the same way it affects cyclists.

Good luck!

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Based on photos you may be okay. That rack is definitely for a bicycle so should hold up to 20-25 kg. Your bike frame should have a couple of holes down by the rear axle for the struts. You will ideally have a pair of threaded holes in the seat stays to connect the front of the rack - some bikes don't have these.

The velcro straps can rest on top of the rack but there's no "clamp" to hold them down or to stop the whole bag-set from sliding off the back. I don't see any hooks on the rear of the bags to clip on top of the rack's side rail.

Cable ties can help, but they're generally not rated for holding a lot of weight, and can suffer from UV degradation. Even the black outdoor ones will fail in time.

Those bags are not small either - You'll definitely feel them in a headwind.

If it were me I'd still try and back out of the sale as unsuitable first. If you're stuck with them, then it may be possible to make them work by modifying them, and possibly extending the rack so it goes further backward, though this can make the bike feel weird with too much rear-weight.

Answer 2

It's going to depend on a couple of things we don't know.

They'll go on the rack with a bit of fiddling - some spare double-sided velcro straps might help stabilise them by adapting existing straps, or perhaps ladderlock straps of the same width. You may need to trim straps or at least tie the slack out of the way until you're happy. I'd get some thin bungee cord to tie to the inside straps on the panniers and loop round the hooks low on the rack.

The biggest issue is whether you've got the heel clearance. That depends on the size of your feet, the length of your chainstays, and the dimensions of the bags.