But... I've never really liked the appearance. The proportions are all wrong. With the extended, braced seat tube, the amount of exposed seat post relative to the seat tube is much too low. I much prefer mountain bikes with a strongly sloping top tube and a lot of exposed post, like a vintage Kona or WTB frame. I'm sure Surly has a reason for this brace, and I'm guessing it involves a 300 pound rider with the grace of a water buffalo who lands jumps while seated. Since I'm a 175 pound, careful old guy who rarely jumps, I think the brace is overkill.
I bought this KM nearly two years ago for not much money with the idea of doing a brace-ectomy. I finally got around to it this winter break. I had picked up an angle grinder at Harbor Freight earlier this year with this project in mind:
I did my first cuts with the cut off wheel on the upper part of the brace, mostly to practice. I'll be chopping of most of this part of the seat tube:
I was worried about cutting into the main tubes, so I left quite a bit of excess material:
After some grinding:
Marking my main cut:
Not particularly square, but I evened it up later with the grinder. It doesn't support a bearing, so it doesn't need to be perfect:
Getting smoother. You can see a vent hole under the brace:
I cut a new slot on the back of the seat tube, with an oversized bottom hole to prevent a stress riser here. Yes, it's off center. It's tough to get a hole started on round tube.
To fix the hole, I threaded in a bolt that was also attached by JB Weld, then cut it off and ground it flush:
Ready to paint:
Post painting. You can see some roughness where I should have filed it better, and the paint gloss wasn't a great match. I ended up roughing over the paint with a steel-wool like sanding pad. That took down the gloss, evened out my tape line, and made the frame's roughness less apparent.
Done! It looks good enough from a few feet away, the overall proportions of the bike are much improved. I ended up taking off about two inches, shortening the seat tube from 590mm to 540mm.
If I crack my seat tube six months down the road, I'll admit this was a mistake. But until then, I'm pretty happy with my modded KM.
Howdy, could the people get an update on how this mod has/had held up? I'm thinking about doing something similar on an older aluminum full suspension frame (though only down to the gusset).
ReplyDeleteI've since the sold the bike, but it was fine as long as I had it. The seat tube is still longer than most other 21" bikes, so I don't see any future concern.
DeleteLooks great! How is she holding up? And how much did that angle grinder at Harbor Freight cost you? Any changes or other tips you might have for me? In pursuit of trying to turn my Surly Instigator into the perfect hooligan play bike, I am thinking about doing the same thing.
ReplyDeleteIIRC my angle grinder was about $40~50. It still works fine several years later, no regrets from that HF purchase. Their drill bits, on the other hand...
Delete