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Project write up - Modifying my bike from All Mountain to Mini-DH

while your DIY attitude is applaudable, cutting that cross-brace like that is pretty scary.

It might be the engineer in me talking, but you have undoubtedly weakened that part of frame, and now, subjecting the frame to greater loads/forces by riding dh with it. That sounds like a recipe for disaster...
 

thom9719

Turbo Monkey
Jul 25, 2005
1,104
0
In the Northwest.
while your DIY attitude is applaudable, cutting that cross-brace like that is pretty scary.

It might be the engineer in me talking, but you have undoubtedly weakened that part of frame, and now, subjecting the frame to greater loads/forces by riding dh with it. That sounds like a recipe for disaster...
I'm not worried. (I'm an engineer too!) Keep in mind, that is a prototype rear end. Even with the trim out, there is still more material than the current production offering. That brace is just to add stifness to the rear end. Even if it snaps in half it *shouldn't* cause a catestrophic frame failure. On top of that, I've got access to a lot of NDI equipment as well. I'll keep an eye on it, but I'm honestly not worried about it at all.

-KT
 

?????

Turbo Monkey
Jun 20, 2005
1,678
2
San Francisco
Why did you cut the tabs off of the other frame instead of just drilling 2 new holes higher up on the mount?

Otherwise cool idea. I love riding my motolite for all but the steepest and roughest trails. It feels a lot faster on moderate downhills. The downside is that it also feels flexy compared to a downhill bike.
 
Aug 4, 2008
328
4
Also the way you mounted tabs... I would have gone and used some different material. Cutting tabs off a frame just seems... Wrong?
 

thom9719

Turbo Monkey
Jul 25, 2005
1,104
0
In the Northwest.
Why did you cut the tabs off of the other frame instead of just drilling 2 new holes higher up on the mount?
I raised the location of the hole about 8mm. That would not have left sufficient edge margin on the tab. I figured using the removable plates would allow me to make a few different plates to change the geometry in the future.

Also the way you mounted tabs... I would have gone and used some different material. Cutting tabs off a frame just seems... Wrong?
Haha, yeah it was hard to wreck a frame! Actually the main reason I did it that way was to save time and money. I was under a big time crunch to get this done before a race on the weekend, so I didn't have time to locate/order/buy any material. Metric drill bits are also expensive. Using the plates from the other frame made my life much easier. That being said, I did eventually find some material and a drill bit and make some plates that bring the geometry back to stock in case I ever wanted to have it back in the normal settings.

-KT
 

RMboy

Monkey
Dec 1, 2006
879
0
England the Great...
Awsome project mate. i commend you...:-)

I wish more people would do this. Some of the engineers on here could turn out some great things.

You just got to be sensible. Thats the only thing :P
 

thom9719

Turbo Monkey
Jul 25, 2005
1,104
0
In the Northwest.
I wish more people would do this. Some of the engineers on here could turn out some great things.
I've always been interested in the DIY stuff. I love the homemade suspension mods. One of these days I'm going to finally build a carbon frame at home. I'm not sure how far down the road before that happens, but it will eventually.

-KT
 

Matt 891

Chimp
Apr 14, 2008
58
0
Salem, VA
A riding buddy recently broke his 4th (!!) mission frame. Warranty will be here soon he says.. :think:

project is awesome though, bro. hope it rides like you hoped
 

Mike.rider

Monkey
Jun 14, 2003
641
0
renton, WA
I've always been interested in the DIY stuff. I love the homemade suspension mods. One of these days I'm going to finally build a carbon frame at home. I'm not sure how far down the road before that happens, but it will eventually.

-KT
Carbon you say, I know a guy who's a materials engineer that knows all about that stuff...
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
2,005
Seattle
I wish more people would do this. Some of the engineers on here could turn out some great things.
Got some drawings in the works. Haven't had time to work on them for a while, but hopefully before too long... ;)
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
2,005
Seattle
Realistically it's going to be a bit before I'm in a position to build anything, but I've got the drawings in the works. It's not anything too crazy, just a fairly clean steel DH bike. I've been riding a one off steel DH bike for a while now (not my design) and love it, I've just got some ideas for little tweaks to improve it.