Hi guys, This bike has a bent subframe (Pic here: http://imgur.com/gallery/SGLwBBZ) and I was wondering if it would be okay to ride it like this? And if there is a way I could possibly fix it? I have tried using a long prybar but it didn't budge. I was thinking of maybe cutting one side of the subframe to make it easier to bend, bending it where I want, then slip some square stock over where I cut and welding it in place. Is that a good idea or no?
Riding with a bent subframe will affect the rider position. If bad enough, can be an issue with comfort and if really bad, handling. That said, if a rider notices the subframe is not straight when riding, I wouldn't recommend they continue to ride the bike unless it bent in a race. Last is better than DNF.
As for straightening, pictures of the frame itself referenced with straight edges and plumb lines are needed to determine possible repairs. Generally speaking however, this will be done with hydraulic pullers or spreaders within a jig of some type.
While cutting to accomodate bending is possible, cutting is normally done to replace sub-assemblies (subframe) with replacements that are straight. If the capability to cut and weld is there, a fabricated subframe may be a better option.
Quote from: Falken Hawke on March 06, 2019, 12:25:57 AM
Riding with a bent subframe will affect the rider position. If bad enough, can be an issue with comfort and if really bad, handling. That said, if a rider notices the subframe is not straight when riding, I wouldn't recommend they continue to ride the bike unless it bent in a race. Last is better than DNF.
As for straightening, pictures of the frame itself referenced with straight edges and plumb lines are needed to determine possible repairs. Generally speaking however, this will be done with hydraulic pullers or spreaders within a jig of some type.
While cutting to accomodate bending is possible, cutting is normally done to replace sub-assemblies (subframe) with replacements that are straight. If the capability to cut and weld is there, a fabricated subframe may be a better option.
Thanks for the reply. If the method I suggested before will.work, I will probably just go with that. I'm not trying to sink a lot of money into this bike and I'm not looking for perfection, just enough so it looks mostly straight. I don't really notice it is bent while sitting on the bike, it's mostly just toward the very back of the bike where it is twisted and shifted over a little
Actually I might just cut it where the bottom and top part meet and bend everything into place then re-weld it. I think it should bend pretty easy if I do that
The subframe of my bike is bent slightly from when it was crashed. After I redid the front end, I had planned on asking a shop what they thought I should do about it. I brought the bike in for inspection, but forgot to mention it. I had planned on asking when I picked the bike up, but they never mentioned or asked about it and it had passed inspection, so I just left it as is. Been riding it for going on 3 years now with no issues. :dunno_black:
If I HAD to fix it, I would probably have a shop just cut the whole thing off and weld on a "new" one though. Trying to straighten the bent one sounds like an exercise in futility to me. I doubt you'd ever be able to get it perfectly straight again.
Good news: I cut the welds where the 2 parts of the subframe meet and bent everything back and welded it up and it looks much better! Not perfect, but it was all I could do with what I had. I'm pretty happy with it! (Pic: http://imgur.com/gallery/5diktBr)
mrdrprof,
That repair looks pretty good. Nice DIY approach. Let us know how it holds up after a few thousands miles.
Kenner
Quote from: Kenner on March 28, 2019, 09:07:10 AM
mrdrprof,
That repair looks pretty good. Nice DIY approach. Let us know how it holds up after a few thousands miles.
Kenner
Thanks! I've put a little over 100 miles on them and they seem to be good so far so I'm hoping they'll hold up for a long time. If they don't then I will replace the subframe