Can I replace a rigid fork with a suspension fork on a Mongoose Alder bike. 27.5 enter image description here.

If so, what particular forks? Under $100.00

  • 2
    On a BSO like this, I wouldn't bother. You're better off saving up for a better bike.
    – Batman
    Feb 24, 2017 at 20:57
  • 1
    What do you hope to gain by adding suspension? If your riding is mostly road, then a rigid like this is fine. Suspension forks are heavy and will impact negatively on your climbing and general acceleration. If you want more comfort, then experiment with dropping your tyre pressure by 5 psi at a time till it feels better without being a drag to ride.
    – Criggie
    Feb 25, 2017 at 1:26
  • Yep - 27+ is about using tires instead of shocks. If you need shocks, you probably want to also go 27 or 29er.
    – mattnz
    Feb 25, 2017 at 2:07

1 Answer 1


Technically yes. You would need to get a fork with a straight steerer (looks like its standard 1 1/8") that was long enough for the frame, probably a 9mm QR dropout (although you wheel is a solid axle, not QR). You would be best with a fork of 80 or 100mm travel or you would upset the bike geometry.

However, a fork will probably cost as much as the bike, and a good fork that makes the upgrade worth while will cost twice as much. Unless you have a fork from a donor bike or lying around, its not worth it as it would be cheaper to buy a used bike with suspension.

  • 3
    Good answer but it's also worth pointing out that in addition to being QR and straight (not tapered) 1-1/8, it would need to be a 27.5+ fork. A strange combination if it can be had aftermarket at all. Feb 24, 2017 at 22:05
  • 1
    @Nathan - Thanks, really good point. Finding straight steerers is getting harder, finding QR's is getting hard, finding those two old features together with this years fad is likely impossible.
    – mattnz
    Feb 25, 2017 at 0:22
  • The easiest way find such a fork is likely to cannibalize one from another similar bike at walmart.
    – Batman
    Feb 25, 2017 at 15:16

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