Frames with adjustable drop outs?

[ishaw]

I've just gone and bought something I shouldn't have. I've not got it in hand yet, but the frame appears to have adjustable drop outs, allowing the use of different wheel sizes. It's coming with 27.5 wheels, so no issues there, but I'm wondering what impact running different wheel sizes on the same frame will have on it?

Anyone had any experience in using the same frame with different sized wheels?

I think it was a bit of a bargain, hence the purchase of something when I should be selling stuff. I plan to use it as a 27.5er, though I think the forks it has fitted are 26er that have managed to run a 27.5 wheel.

When I get it, I'll know more, hoping to be a bit more knowledgeable before it arrives, as any info will help me decide on the build, whether to keep it 27.5, drop to 26, change the forks etc.

Speaking of forks, are rock shox csus the same for 26, 27.5 and 29? I think they are, certainly a 29er Sid I have had the same length stanchions as a 26er if memory serves. Wondering if I could just buy a set of 27.5 lowers for a Reba and swap them out, along with the air side damper (or accept change in travel)?

 

[stevet1]

I'm wondering what impact running different wheel sizes on the same frame will have on it?

Well of course BB height will increase by half the increase in wheel diameter. If you just change one wheel to a different size then BB increases by
1/3 of the above figure if its a front wheel
2/3 for the rear wheel
If you change both wheels then head angle remains the same but the amount of trail will change, hence why forks in the bigger wheel sizes have different (larger) amounts of rake. This is a bit of a hot topic with some manufacturers and suspension guru's claiming that actually less rake is still a good thing as it promotes more stability at speed.
Best thing to do is experiment.