Goblin Cockpit Fit
So I've been riding my 20" green Goblin now for about 2 months and what a stellar machine! Handles great and climbs/descends like a skinned cat! I actually just bought the frame and fork together and built the rest of the bike up from a used component set, so it barely resembles a stock Goblin. I really like the handling and it's climbing ability a LOT but even after a fair amount of saddle time, getting fit by a good friend who is top notch mechanic, and a few changes in riding style I'm still noticing a fair amount of discomfort. I'm about 5'11" with a 33" inseam, so I'm not having much issue with the standover height of the frame, but I feel really leaned over on the bike and I have a fair amount of lower back pain after about an hour in the saddle. I also don't feel really comfortable standing and pedaling as I do seated. My stem is about 100mm and my bars are 685mm according to my measurements. I recently rode a friend's 2013 19" Rumblefish and was really impressed with the whole cockpit feel. I know the Goblin is meant to be more of an XC race bike and the Trek is supposed to be a trail bike, but I'd love to have the more comfortable, upright riding position with the wide bars. So, basically what I would like to ask is, would a cockpit feel similar to the Rumblefish be achievable on my Goblin? Or would the longer top tube and other geometry restraints prevent me from obtaining the shorter reach, wider bar, upright position feel that I would like to have? I'm just trying to figure out if it is even feasible before I drop $100+ on a shorter stem/wider bar combo.
I am the same height as you and I ride a 18 inch Goblin..I ride a medium in all my mountain bikes..I run a 90mm stem..I still use a flat bar but you could go with a bar with maybe a 2omm rise or so...I like my bars narrow and run pretty narrow bars..I think my current ones are 620 mm..On my All mountain rig I am running a 70mm stem with a 30mm rise bar...every bike I have bought has come with a 100mm stem standard and I have had to get a shorter one as I experienced the same issues you described...by changing out the stem I eliminated all most all of those issues..I still get a little pain in the back on real long rides on a hard tail on rough trails..just goes with a HT..
Forgot...by setting up the Goblin cockpit almost identical to my Stumpjumper they feel very similar out on the trail.
I am 5'11" with a 32" inseam. I ride bikes with ~600mm top tube which is usually a medium. 100mm stem, 660mm bar. I think the top tube of the 20" frame may be too long for you.
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A couple of thoughts:
1. Get a shorter stem
2. Get a zero setback seatpost
3. Move your seat forward
All of these should shorten the effective top tube length and make it easier on your back. A higher rise stem also can help - Salsa has some 15 and 25 degree stems that you can find on eBay. If you buy one, make sure it isn't a model that has been recalled by Salsa, as they were known to crumble. See their website for more information.
Goblin Cockpit Fit
A 20 inch frame with 622mm top tube might be a little long for you but not crazy long. However, In my opinion and experience, most 5-11 riders would be on an 18inch. I would bet a 90mm 17 degree stem and a zero setback seat post would make your geometry more comfortable. But I might contact Airborne per below and ask what it would cost to get you onto an 18inch frame. From Airborne's website:
We will work with you via phone and/or email to determine the size of Airborne bike that fits you best. You may need to purchase additional items to fine-tune fit once you have received your bike, such as a longer/shorter stem, longer seatpost, wider bars, etc. If you can't dial your fit in after purchasing these items, please contact us and we can work with you to get a different size.
I'm 5 9 and I ride the Med. The fit feels perfect. You might want to switch if you can.
The 20" you are talking about is my former personal Goblin frame/fork that you bought from me, correct? Glad you are enjoying it! Sorry to hear about the back issues.
At 5'11" with a 33 inch inseam I personally think the 20" isn't the *wrong* size for you, unless you have something else going on like short T-rex arms or some sort of physical issue. Truthfully you are right at the height/size where you could ride either size (18 or 20) depending on personal preference or set-up.
Before you decide to buy a different size frame, I'd recommend looking at maybe a shorter stem and a zero-setback post (like a Thomson).
Also, often lower back pain can be addressed by doing core-strengthening excercises.
Hope that helps!
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I have nearly the exact same physical dimensions and bike. I have been dealing with some of the same issues. I moved to an 80mm stem and that helped dramatically. I MAY even try out a 70mm. However, I'm running a Thompson set back post and think it pushes me back a little further than the stock one.
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