Recommendations for 27.5 plus open mold frames?

Discuss light weight issues concerning mountain bikes & parts.

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apctjb
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Joined: Mon Oct 30, 2017 11:27 pm

by apctjb

Looking to build a light weight (<20lb) hard tail for my wife. Primarily going to be used in Baja where the trails are sandy so would like to run larger tires (2.5" or larger)

I have purchased open mold road frames (and been happy with them) but looking online its hard to tell what the max tire size the hardtail frames can handle.

So looking for recommendations for 27.5 hardtail frames that can accommodate larger tires. (2.5-2.8"). What's out there?

Thanks

by Weenie


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silvalis
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Location: Aus

by silvalis

Have a look on aliexpress. There are a few boost HT frames on there that aren't on ebay.
Chasse patate

apctjb
Posts: 59
Joined: Mon Oct 30, 2017 11:27 pm

by apctjb

Another question.

Is it possible to use a 29'er frame with 27.5 rims and high volume tires? As 27.5 plus wheels end up being close to the diameter of 29 wheels running low volume tires seems like you could, but perhaps I am missing something?

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LeDuke
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by LeDuke

I've seen a couple of 27.5+/29er Boost frames out there. As suggested, check AliExpress.

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silvalis
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by silvalis

apctjb wrote:
Mon Dec 25, 2017 9:25 pm
Another question.

Is it possible to use a 29'er frame with 27.5 rims and high volume tires? As 27.5 plus wheels end up being close to the diameter of 29 wheels running low volume tires seems like you could, but perhaps I am missing something?
Yes and no. Depends on the frame in question (if the stays curve, etc) and of course the rim.
You'd have to do some experimentation - and play around with plus tyres, like try 2.8" instead of even 2.5WT (although thats probably not worth while)

And don't forget that if you go from a 29er frame that runs 2.35" tyres you're going to drop your bb 10mm or so going to a 650b/2.8"
Chasse patate

apctjb
Posts: 59
Joined: Mon Oct 30, 2017 11:27 pm

by apctjb

And don't forget that if you go from a 29er frame that runs 2.35" tyres you're going to drop your bb 10mm or so going to a 650b/2.8
Perhaps a dumb question but if a 650b with 2.8 tires has the same diameter as a 29er running 2.3 then why would the bb height be any lower? Just not understanding why, thanks.

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silvalis
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by silvalis

Because, despite what the marketing told you early on going from a 29 to a 27.5+ will shrink your wheel diameter and drop your bb anywhere between 5 and 15mm
Chasse patate

apctjb
Posts: 59
Joined: Mon Oct 30, 2017 11:27 pm

by apctjb

Because, despite what the marketing told you early on going from a 29 to a 27.5+ will shrink your wheel diameter and drop your bb anywhere between 5 and 15mm
Okay; if diameter is less then makes sense.

I had read that a 2.8 on a 650b rim was the same diameter as a 2.3 on a 29 rim but perhaps that is not the case. Do any of the tire manufacturers give actual dimensions for the profile of their tires mounted on different width rims? I would like to draw this all up in CADD and verify.

by Weenie


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