A friend let me borrow his Jet 9, a great bike! In fact he wants to get a nicer bike & sell me this one cheep. Unfortunately, the seat tube on the Niner is way too steep. The tip of the saddle can only be 4 cm behind the bottom bracket. My current 26er bike has the saddle 11cm back of the BB & i like the fit. I have never seen a 7 cm set back seat post.
Any ideas on how to make this work?
Thanks.

you might be over thinking this. if the bike is your size, just ride it like it is for a while. tweek from there. it's really not a fair comparison between the geometry of that bike and your current 26er.

You do know that there is some adjustability of saddle position where the seat attaches to the seatpost, right? The horizontal position of the saddle relative to the bottom bracket is not something that most people even think about and you probably won't even notice since the geometry of the Niner will be so different anyway.

I am kind of a old school bike geek who did plenty of riding before the mountain bike existed. I have read plenty of books on bike fit. It's pretty important to me that my bikes are set up correctly. Why would body position on a niner be different than on a 26? Not trying to argue, just trying to understand.

because the wheel size is a huge variable in geometry. increasing the wheel size greatly changes the way the bike handles, niners are amazing. i have a jet9 and also love it. but hey, you have read a few books 20 years ago, i'm sure you know more about the subject than the best 20er company out there right?

They steepen the seat tube to fit fatter tires and suspension travel with the bigger wheels and the same wheelbase compared to a 26. That puts more weight on the front end which can be a good thing if you know what you're doing. Otherwise it just makes endo's easier.


A setback post and the saddle all the way back can get you 4 or 5 cm without much trouble. That should be close enough.

Top tube length and stem length can play a big role in how the bike fits and feels right now as well. I agree on getting some miles in and getting used to the bike as it is. I personally like having the seat as far back as possible. I have trouble lifting the front tire over rocks and obstacles. So having the center of gravity further back to me is a plus. I'm not sure how the 29er geometry works with that.

Just get a set back seat post cheap easy and it will get you the fit you like.

The jet 9 and CVA rear suspension is amazing as you have found out. If you can get that bike for cheap jump on it and buy a new seat post.