Running 27.5 on a 29'er Sight Frame..?

Author	Message

Jasonfitzz

O+ FL

Posted: Dec 16, 2020 at 5:41

Quote

So I've got a 2021 27.5 Norco Sight Frame on order from a local shop, and have all the parts purchased to build the frame up. Going to a 170mm fork and a 55mm stroke coil shock.

However, there's questions about when (or IF) the frame will show up, but I could get a 29'er frame much sooner. I'm not interested in riding a 29'er (I'm super short and just didn't enjoy the feel of the higher BB).

Wondering if building a 29'er frame with 27.5 wheels would make the BB way too low, or throw off the geo too much. The 170mm fork would offset the front wheel difference a bit.

Any insight or help would be appreciated, thanks!

Currently on a 2019 27.5 Carbon Norco Sight, would be moving most my parts over to the new frame.

sdaly

O+

Posted: Dec 16, 2020 at 7:35	Quote
Hardly seems worth it to spend all that money on a new bike to screw it up and set it up to negatively effect the performance

Jasonfitzz

O+ FL

Posted: Dec 16, 2020 at 11:07

Quote

sdaly wrote:

Hardly seems worth it to spend all that money on a new bike to screw it up and set it up to negatively effect the performance

I totally agree, but I mean that's entirely the point of the thread, to determine if it would or would not negatively impact the performance significantly.

I know the fork height difference from the 160mm (stock) to the170mm is 10mm, and the wheel difference would be approximately 19mm from what I've found. So a net difference of 9mm difference up front (stack height).

In lowering the front end 9mm I'd be increasing the head angle, but because the rear axle would be lowered too, I'm not sure what the actual outcome/head angle will be. I'm also thinking the BB would be lowered but not sure how much.

My intuition is that it would throw it off too much, but I just thought I'd throw it out there to see if anyone (bike nerd) would know the real outcomes.

Thanks!

sdaly

O+

Posted: Dec 17, 2020 at 5:23

Quote

Sounds like you already know the answer. Why would they go through all the R&D cost, and manufacturing expense of offering 275/29 options when they could just sell one frame compatible with both wheel sizes? This would also be a HUGE pro for marketing as well, to be able to run both sizes or even mullet...there must be a good reason for the extra cost/effort on their part.

Not to mention you're only upgrading from a 2019 frame, so any marginal gains could easily be lost from doing something goofy to it. It's not like you're upgrading from a 10+ year old bike

mrpercussive

Posted: Dec 19, 2020 at 19:45	Quote

Jasonfitzz

O+ FL

Posted: Dec 21, 2020 at 5:52

Quote

mrpercussive wrote:

Very cool, thanks for sharing!

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