Boost wheels on non-boost frame. Dangerous?

[Zak]

Hi

A long story short. I have had a 1100g wheelset build for 7,5 kg XC hardtail build. It has turned out the frame is a non-boost frame and the rearhub is boost. The wheel can with a light push with one finger fit into the carbon frame since the rear-triangle is quite flexible. But is it safe to ride the bike with this very light pre-tension on the reartriangle.

My first thought is it will be fine since the pre-tension is so small compared to the forces on the rear-triangle when riding. But is there some safety issues I'm not aware of? The build is for a light 45 kg rider.

I can ofcourse get the wheel rebuild but then I have to invest in a new expensive hub and so on. So if it can be avoided it would be great.

Thanks

[protocol_droid]

Which hubs did you go with? Extralite?

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[Zak]

Yes Extralite hubs and Duke rims

[Karvalo]

Consider that when you simply slot the wheel in, the extra 6mm means the stays and dropouts are angling away from each other. As you say, this part could well be pretty easy. However, if you then fit and tighten a thru axle (assuming you can get the threads to engage properly in the first place since they're no longer aligned) you're forcing the dropouts back to parallel, putting what I would imagine is a very concentrated stress on the stays just forward of the dropout where you're now bending them in a zigzag.

It doesn't sound good to me.

[F45]

I did this for a while, 148mm hub in a 142mm carbon hardtail frame. Never had a problem.

[02GF74]

I would not do that. My concern would be additional stress on the frame and not knowing if the wheel is centred since it is unlikely that each side will move out by the same amount.

.... but as you see, someone has ridden a bike like this without any problems... so up to you.

[Bumbabambuee]

I have done this on 2017 model of Pivot 429SL after a "recommendation" from an official Pivot dealer, who also happpens to be my friend. Probably he wouldn't have recommended it for some random guy but told me it has been done many times and SHOULD be good to go.

Now after running it for 3 years, some of my own observations:
- Frame is all good
- You must of course use longer thru axle
- The threads fit fine
- You must re-adjust rear brake and derailleur
- Rear brake is where you notice the slight misalignment. Real struggle to get it rub free. Similar sitiation as the rotor would be very slightly bent