DIY Rear Suspension to Hard Tail Conversion



Bryches

New Member
Aug 14, 2007
4
0
0
I'm fairly new to the bicycle world past knowing how to ride one, haha. I recently started using my older mongoose 21 speed this summer to get to work and around campus. I have found from personal experience and the internet that it is much more inefficient than a road bike so I have been trying to improve it without spending a lot of money since it mostly sees road. I inflated the tires more and adjusted the rear suspension to as stiff as I can get it. It improved a lot. I thought the other day about simply removing the rear shock / damper assembly and replacing it with a rigid metal link that I can machine at work. I'm thinking this will make a much rougher ride but more efficient bike on the road. Plus I can switch back and forth depending on what kind of riding I will be doing. The thing is that I'm no expert in bike design so I am wondering how altering the bike like this will change the stresses in the frame. Obviously a factory hard tail has different geometry than what mine would have. Just want to make sure it's not going to snap while im riding it, haha. Any thoughts? Thanks in advance.
 

cruisin

New Member
May 21, 2007
93
0
0
You will add to the stress but only time will tell if it will break. And be aware aluminium often breaks without warning.
 

Bryches

New Member
Aug 14, 2007
4
0
0
I'm pretty sure the frame is steel, it's kinda heavy. Aluminum is much more fun to machine but I can make the link out of steel if im worried about it breaking.
 
Jun 6, 2006
1,696
6
38
Don't go too firm on the tires if they are mountain size. That will result in bouncing the bike or the suspension more. As a roadie I know that bouncing your bike into the air on minor bumps is just as inefficient as articulating the suspension. Don't use 75 psi unless you get some 1.25's.

If you machine your own link, why not put some sort of polyurethane bushing around the mounting bolt? It would take the more extreme shocks while staying rigid during normal use.
 

dabac

Well-Known Member
Sep 16, 2003
2,294
284
63
52
Bryches said:
.. I thought the other day about simply removing the rear shock / damper assembly and replacing it with a rigid metal link ... I am wondering how altering the bike like this will change the stresses in the frame. Obviously a factory hard tail has different geometry than what mine would have.


The point of concern isn't the geometry, but the strength of the shock mounts. If you replace the shock with a solid link they will receive a much more sudden load than when there was a shock there when you go over bumps.

GS suggestion of using some sort of rubber bushing would be a good one, if you can swing the machining. Otherwis you'll simply have to chance it, ride it and inspect frequently.