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Hi I currently ride a decent spec 2003 mongoose full suspension but I find that the seat stay is slightly too narrow to run my maxxis high roller 2 2.3 tyre without it rubbing on the frame. In theory if I was able to find an appropriate length seat stay of I wider fitting even if it's not for my frame would I be able to swap out the seat stay and thus run my wide tyres? I don't see an issue as long as the seat stays are the same length and have the same shock fitting and attachment to chain stay.

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  • Good luck! Finding another piece that matches your fittings and is wider is unlikely. There's no standardization here, not even between Mongoose models. Nov 5 '16 at 11:45
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    I have actually found a seat stay online for a 2005 kona that has the same fittings and is a good 15mm wider. Chain reaction clearance of old parts. I'd never pay £200 for it but I was thinking at £7.99 I might give it a go
    – Dave L
    Nov 5 '16 at 11:51
  • For that price - totally go for it! Just be careful taking the old one off so that you can reuse any rubber fittings and bushings, and can revert if the new one doesn't fit.
    – Criggie
    Nov 5 '16 at 22:21
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seat stay this is what I was thinking of swapping out

enter image description here

enter image description here

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EDIT: This answer supposed that the rear chainstay was welded to the frame. As such its inapplicable to this question, but being left for completeness.


That's a lot of work to cut off the old seat stays and weld in new ones. Plus you'd have to either cut them off an existing bike, or make the new seat stays up out of fresh steel.

Getting it done by an experienced and qualified framebuilder would be safest, but I'd be surprised if it was cheaper than a whole new bike.

The details of your suspension aren't obvious from your question - can you add a pic showing what you want to try?

Do you have rim or disk brakes? With rim brakes, the bosses will have to line up correctly, and with disk brakes it depends if your rear caliper is mounted to the seat or chain stay. Doubt that you have caliper brakes.

Remember, in 2003 a 2.1" tyre was huge. Noone anticipated tyres would become bigger-than-huge.

Your final option might be to trim your tyres a bit - removing some of the knobs might help fit in the frame. Or simply return to 2.2" or 2.1" tyres.

I'd strongly advise AGAINST trying to cold-set your frame with any sort of jack or puller - that is likely to crease the frame and decrease the structural strength required.

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    Hi it's a mongoose full suspension frame running hydraulic disc brakes front and back. I'm not sure how to load photos up on here at all but the seat stay chain stay and rear dropouts are a bolted together 4 piece set where the chain stay is bolted to the rear dropouts at the bottom and the seat stay is bolted to the dropouts at the top and connects to the pivot point on the rear shock. The rear caliper is bolted to part of the dropout which also looks to be removable
    – Dave L
    Nov 5 '16 at 11:29
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    Criggie - I think he was suggesting transplanting a different rear triangle onto his bike rather than widening the one he has. Also Gazzaloddis were available in 2003 so 2.1s weren't that huge.
    – DWGKNZ
    Nov 5 '16 at 11:29
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    Going to be better/safer/stronger to just swap the entire bike. Bikes less than about $1k are usually replaced and not upgraded... the economics just don't usually work out unless you have a large selection of nearly free parts and an equally large amount of free time and know-how. HOWEVER, if the tires 'nearly fit'... you can try cutting off the knobbers, on the left and right sides, to increase the clearance without modifying the frame.
    – david1024
    Nov 5 '16 at 14:27

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