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Any Reason I shouldn't get this size?

727 views 11 replies 5 participants last post by  GPRider08 
#1 ·
Found an '07 Stumpy FSR S-Works frame on eBay which seems to be going for a good price. Problem is, it's an XL, and at 5'11", a large/19" typically fits me well. However, I looked at the measurements of my last bike and compared them with those of this frame, and the TT is nearly identical. 615mm actual TT length for the '08 Rockhopper, versus 618mm for the Stumpy. So, it seems the reach would be ideal. Any other key sizing issues I should consider? Not too worried about standover, but it seems to actually be lower on the Stumpy.
 
#5 ·
i am 5'11 also and i am kinda with apat13. i am in the middle of medium and large... if you are more of a speed demon then go with the large but if you are looking for maybe some technical stuff that needs a bike to be a little bit mroe manueverable then go with a medium....i don't see xl being a reasonable option.
 
#6 ·
I figured so, but thought I would ask. It seems the top tube length is really close to what I'm used to (only 3mm longer). I just didn't know if there were other measurements I should be looking at.
 
#7 ·
GPRider08 said:
I figured so, but thought I would ask. It seems the top tube length is really close to what I'm used to (only 3mm longer). I just didn't know if there were other measurements I should be looking at.
Standover , if you cant stand over the bike without harming the "boys" .
 
#8 ·
I decided against it, though standover wouldn't have been much of an issue. I think I'll go to the LBS and hop on an XL Stumpy sometime, just to see.
 
#9 ·
Because of the design of the Stumpy frame, standover will actually be lower than on your Rockhopper - but that is only one of many measurments to consider. In reality, the overall significant measurements between the two frames are drastically different.

Seat Tube: 483mm -> 533mm = 50mm (full 2.1 inches longer)
Effective Top Tube: 615mm -> 638mm = 23mm (almost 1 full inch longer)
Wheelbase: 1101mm -> 1151mm = 50mm (full 2.1 inches longer)
Head Tube Length: 120mm -> 176mm = 56mm (2.2 inches longer, current steerer would be too short).

The seat-tube being much longer means you would simply run less post showing, but the 1" difference in Top Tube length is drastic. It would require you to run a super short stem (40mm) to obtain the right cockpit feel, which in turn would compromise the handling on a bike that was designed around a 90-110mm setup. Your weight distribution would be too far to the rear, making it track horribly on the climbs and making front suspension performance suffer on the descents. The longer wheelbase would make the bike more stable on long fire-road descents, but you will greatly sacrifice technical handling as a result, especially with that shorty stem. Finally, the over 2" divverence in head tub size would mean that your current fork would not fit, and you would either have to get a new steerer or a new fork. On top of that, this would be the same as raising your handlebars 2" compared to the positioning you are used to, again creating too much of a rear weight bias. All in all, the XL would ride like a completely different machine compared to your rockhopper: sluggish, awkward positioning, and a strong weight bias towards the rear wheel. To compensate for the weight bias you would have to run extra pressure in the rear to stiffen it up to overcome pedal forces, while running less pressure in the front because there is no weight on it. The result would be a bike that was very springing in the back and very soft in the front - so brake dive, packed up suspension, and bottom outs become a real concern as well.

Hope this helps.
 
#10 ·
Thanks. The two primary measurements I'm familiar with are toptube and standover. As you said, the TT isn't a big deal. However, I thought the TT was shorter on the Stumpy versus the RH. Turns out I was looking at the 21" RH versus the 19", so I can see now there is a substantial difference.
Regarding the other info, I wasn't completely sure what those other measurements would affect. This will help me a lot, as most likely I'll be buying used.
 
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